EF-UK Issue 82 - British Electric Flight Association - ef

ELECTRIC FLIGHT U.K.
ISSUE No. 82 AUTUMN 2005
THE MAGAZINE OF THE
BRITISH ELECTRIC
FLIGHT ASSOCIATION
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Electric Flight - U.K.
Issue 82 - Autumn 2005
"To Encourage and Further all Aspects of Electric Model Flight in
the British Isles and Elsewhere" - B.E.F.A. Constitution
CONTENTS
BEFA Committee 2005/6 ........................... 4
Chairman's Chatter .................................. 5
Current Lines ........................................... 6
Letter to the Editor .................................... 7
New-2-U ................................................... 9
Readers’ Models ....................................... 19
Let it Out! ................................................ 22
Fillip for a Filip ........................................ 25
Chester Electric Fly-In 2005 ..................... 33
A-10 Warthog .......................................... 36
3rd Annual PANDAS Fly-In .................... 39
Some LiPo Experiments ........................... 45
TLC from your TLO ................................. 50
Event Calendar ....................................... 60
For Sale / Wanted .................................... 63
New to Electric Flight? Start Here ............ 65
BEFA Sales ............................................. 66
Advertisers Index ..................................... 66
Cover Photo: The cover photo is the outstanding Bell 47G helicopter of Ross
Mortimer taken at Middle Wallop on 3rd July 2005. The photograph was taken
with the model coming in to land after an extremely scale flight. It is built from
the Century Helicopters kit and uses a Hacker C50-16XL motor, Jeti Advance 75
Opto plus speed controller, and normally 2 x 3S4P (8000mAh) LiPo packs for 35
min flight time. Ross has made a lot of effort in finishing the model with cockpit
detailing, pilot and weathering of the painted surfaces..
NEXT ISSUE. The copy date for the Winter 2005 issue is 15 November 2005,
with the magazine due for publication by 23 December 2005.
DISCLAIMER
B.E.F.A. and Electric Flight U.K. wish to point out that the content, techniques and opinions
expressed in this magazine are those of the individual authors and do not necessarily represent the
views of either the Editor of this magazine or B.E.F.A. and its committee.
© All information in this magazine is copyright of the authors. Any request to use information
from this magazine is to be made to the editor (contact details overleaf).
All reasonable care is taken in the preparation and compilation of the magazine, but B.E.F.A. and
its committee cannot be held liable for any error or omission in the content of this magazine or any
subsequent damage or loss arising howsoever caused.
To allow proper appreciation of the photographs used, colour copies of them will be posted on the
B.E.F.A. website after publication of this magazine. If you can, check them out at www.befa.org.uk
E.F.-U.K.
3
BEFA Committee 2005/6
Chairman
Robert Mahoney
123 Lane End Road, High Wycombe, Bucks. HP12 4HF
EMail: befa@rlmahoney.co.uk
Secretary
Peter Turner
37 Church Street, Horsley, Derbyshire. DE21 5BQ
Tel: 01332 881 265, Email: peter@alport.fsnet.co.uk
Membership Secretary
Bob Smith
1 Lynwood Avenue, Tollesby, Middlesborough, Cleveland. TS5 7PD
Email: bob.smith007@ntlworld.com
Treasurer
Bob Smith, details as Membership Secretary
EF-UK Editor
Jan Bassett
111 Plantagenet Chase, Yeovil, Somerset. BA20 2PR
Tel. 01935 472743, E-mail: editor@befa.org.uk
Events Co-ordinator
Terry Stuckey
31 Dysart Avenue, Kingston-upon-Thames, Surrey. KT2 5QZ
Email: terrystuckey@blueyonder.co.uk
Competition Secretary
Bob West
51 Haweswater, Huntingdon, Cambs., PE29 6TW
Tel. 07970 238 704, Email: robertj.west@tesco.net
Midlands Representative
Roger Winsor
14 Butler Gardens, Market Harborough, Leics. LE16 9LY
Email: Rogerwinsor7@aol.com
Northern Representative
Bob Smith, details as Membership Secretary
Southern Representative
Dave Chinery
251 Station Road, Hayes, Middx. UB3 4JD
Email: DavidDchinery@aol.com
South West Representative Jan Bassett, details as Editor EF-UK
Indoor & Free-Flight Rep.
Gordon Tarling
87 Cowley Mill Road, Uxbridge, Middx. UB8 2QD
Email: gordon.tarling@ntlworld.com
Technical Liaison Officer
Alan Bedingham
17 Highcliffe Close, Wickford, Essex. SS11 8JZ
Email: bbba18333@blueyonder.co.uk
Public Relations Officer
John Thompson
19 Park Avenue, Liversedge, West Yorks, WF15 7EQ
Tel. 01924 515 595, Email: johnty99@ntlworld.com
Webmaster
Jan Bassett, details as Editor EF-UK - (www.befa.org.uk)
Safety Adviser
David Beacor
34 Chestnut Close, Brampton, Huntingdon, Cambs., PE28 4TP.
Please enclose an SAE with all correspondence to the committee.
4
E.F.-U.K.
Chairman’s Chatter
Dear members,
Welcome to the autumn issue of your Electric Flight U.K. Magazine. Time does
fly when you are having fun.
I would like to give you the membership some time to think if you could help with
the working of your Association! At the 2006 AGM we will need new people for the
position of Editor and Secretary. As the present incumbent's have given indications
that they would like to stand down. Please talk to me if you can help the Association
in any way.
It's sad to report that some monthly magazines get the dates and places incorrect
for BEFA events in their Diary dates pages. If you have use of the internet please
use the BEFA pages or phone the organizer of the event to confirm date and place.
I took the photograph below at the recent Aspach event. The model is the awesome
Horten IIIe of Franz Schmid. Looking at the photo you wouldn’t believe it has a
10.5m (34 ft. 5 in.) wingspan and weighs 19.4kg (42.8 lb.). There will be more
from Aspach in the next issue.
That's all for now so KEEP THE WATTS UP!
Robert Mahoney
E.F.-U.K.
5
Current Lines
from the Editor
Erratum
Due to a mistake at the printers, Fig 1 was printed twice on page 61 of issue 81,
Summer 2005. The lower image should have been Fig 2, included below.
Content
A big thank you to all the contributors to this issue. You may notice that this
issue is thinner than normal, due to the lack of items submitted. Not only does it
mean less pages, but much more work for me in seek items. If this magazine is to
survive more contributors are desperately required. Have a quick think whether
you can send me any of the following:
•
•
•
•
General or Technical Articles including Hints & Tips.
Product Reviews, New products & items of interest.
Electric Flight Event write-ups.
Photographs of your models.
Please send Digital photo files or photographic (6” x 4” or bigger) prints to the
editor. If you supply a return address, photographic prints supplied will be returned,
unless specified otherwise. Digital photos should be sent at the highest resolution
possible, in colour, and uncompressed or low compression format. Please do not
send inkjet prints as too much quality is lost in the multiple conversions - please
send the photographs by email or CD. Please send as many details of models as
possible, preferably at least span, power train, battery & flight performance.
Notice
I am standing down from the position of Editor at the next AGM in March 2006.
At that point I will have produced 20 issues of EF-UK during my 5 years as Editor.
The BEFA will a volunteer to take over as Editor - could it be you?
Regards
Jan Bassett
6
E.F.-U.K.
Letters to the Editor
Firstly a letter on VarioPROP propellers from Malcolm Mackendrick
Following the article on Variable pitch propellers by Don Stanley in the last
magazine. I have a bit of experience of 3-bladed VarioPROPs- I own 5.
The first was used to find out the best pitch & diameter for an AXi 2808/20
motor which needed a smaller diameter propeller for an SRX 250 model.
Having found out the best size I bought 4 fixed pitch propellers that size (8” x
6”). With my own made hubs and made 2 very successful 3-bladed propellers
- one rigid & one folder (used in pushing mode on a flying wing).
I now have a Blenheim bomber using two 3-bladed propellers (8.2” diameter)
running in left & right handed. I also have an untested 2m span, own design,
bomber which also uses left & right handed 10.5” diameter 3-blade
VarioPROPs.
Setting up is easy as you just put one propeller on a motor & adjust the pitch
to draw the desired amperage. Then reversing the motor you do the same
with the other propeller.
Moreover the running costs of VarioPROPs are low as the replacement carbon
blades cost from • 1.50 to • 3.30 each depending on hub size and diameter. I
broke all 6 blades on the Blenheim taking off with the retract switch in up
position. I had switched on the model while it was sitting on the runway &
the wheels did not lift until they were more lightly loaded.
The hubs are not usually damaged and are also very attractive with the
appearance similar to full size aircraft propeller hubs.
I too have several VarioPROPs and I’m impressed by the extremely good build
quality and range of propellers that can be built. Three sizes of hubs are available
for 2, 3, 4 and 5-blades and for various shaft diameters.
The 6A hub is the smallest with blades for 5.1” to 9.6” propellers and folding
blade holders for any blades with 6mm wide roots and up to 350W.
Next is the 8B hub with 7.9”
to 10.4” blades, plus folding
blade holders with 38mm and
42mm spacing for 8mm roots
and up to 700W.
The 12C hub is the largest
with 10.1” to 15.0” blades and
folding blade holders for 8mm
root blades with a 48mm An 8B, 2-blade, hub with CAM 10” x 6” folder blade &
holder (left) and a 9.7” scale blade (right).
spacing and up to 2.2kW.
E.F.-U.K.
7
Next another letter by Malcolm Mackendrick illustrating potential problems with
LiPo packs.
Since my last report on my LiPo battery experience, in Issue 81, I have
calculated from logged flying times the number of cycles – i.e. discharges
and recharges that my batteries have had. I only started logging individual
battery cycles since the beginning of July 05.
The two 3S2P, 3200 mAh, carbon plate backed packs have done between them
182 cycles unlogged & another 16 logged separately. Their present capacity
has reduced to 2495 mAh for the battery purchased in June 04 & 3203 mAh
for the battery bought in August 04.
The total logged air time for these 2 packs has been:
6 hours 20 minutes in an Eco 8
1 hour 45 minutes, in series, in a big 80” (2m) model with an AXi 4120/18
5 hours 18 minutes in a Playboy (also in series), and
13 hours 37 minutes in a Crossfire
A total of 27 hours in the air.
7 packs of 1600 mAh 3S1P batteries purchased at different times have between
them done 375 unlogged cycles. I have now discarded 4 of these as being well
below par at 392 mAh (purchased June 04) 445 mAh (August 04), 534 mAh
(February 05) & the one deliberately shorted out (June 04).
I cannot separate the usage of these 1600 mAh packs, however, the total
flying time has been 34 hours and 7 minutes. In 3 of the models these packs
are used in they are connected in parallel. The remaining 3 packs were bought
in July 05.
I do not generally fully discharge to 3 volts/cell on each flight, just to a
conservatively set timer. Most flights are about 10 minutes as that is enough
time before boredom or neck-ache sets in!! Besides the landings are part of
the fun.
I will report on total individual battery cycles when I have enough data.
The capacity reduction of LiPo batteries is a well known problem, although there
is very little data on the actually life and it’s relation to discharge C factor. To be
able to really build any evidence the data needs to identify the number of cycles
and at what average discharge C they were at. Potentially it is even more difficult
than that as most cells have a increased rating for short durations and the profile
of current draw may be important.
Probably the only realistic way of coming up with any meaningful data is to cycle
the cells under controlled conditions “on the bench”. Different charge / discharge
profiles could be used, although the time & cells required would be exorbitant.
8
E.F.-U.K.
New-2-U
A Brief Round-up of New Items of Interest.
If you are a manufacturer or retailer that has something new they want to
share with the readers, please send details to the Editor (addresses on page 4).
Above is the latest 2005 Kontronik catalogue, which is now available, as are all
the products in it. In fact it is rather more of a New Products Catalogue, as most
of the established and familiar products are not mentioned do in fact remain
available. It is a dual language catalogue with a full English language treatment.
As the cover suggests, emphasis is put on their serious venture into outrunner
motors, with the launch of the KORA range - KORA 10, 15 and 25. Each is the
same diameter with 3 different lengths to yield power handling of 300W, 400W
and 600W respectively. The KORA 25 can also handle 1000W for take-off and
aerobatic manoeuvres. Each size is available in 6 winds to give various RPM/V
ranges and to suit differing cell counts.
The mechanical arrangements are rather different to most established outrunners
as there is a large diameter, ball-raced, ring bearing supporting the open
end of the can, with a resultant improvement in dynamic rigidity.
For the smaller, lower power, range Kontronik have introduced a German
manufactured “Dancer” group of 4 outrunners. The MICRO Dancer is their tiny
E.F.-U.K.
9
entry into the 400 class weighing 46g, handling 120W and capable of taking
gearboxes. The remaining 3 are based on a common diameter of 32.5mm but in 3
lengths. The MINI, MAXI and EVO Dancers cover the power range of 100W to
250W and can swing propellers up to 14” diameter.
Two new brushless controllers enter the range with the cost effective, LiPo
compatible, “Fit and Fly”, PIX range (18A & 30A). Additionally, 2 new 55A JAZZ
controllers with 18-cell and 30-cell ratings and both having BEC outputs - a first.
The new 2005 Kontronik catalogue is available for £1 from Alan Fry, ImporTekniK,
29 Braiswick, Colchester, CO4 5AU.
Hacker Brushless Motors have been busy creating 2 new ranges of 12-pole outrunner
motors, the A20 and A30 series and the X-series brushless controllers developed
for them. The A20 has a 20mm diameter stator and is available in Short, Medium
and Long versions with 2 winds being available for the M & L motors.
The Hacker A20-S, A20-M and A20-L motors
Motor
Wgt
Battery
A20-34S
1500
29g
2 LiPo
2-6
8
8” x 3.8”
A20-30M
980
42g
3 LiPo
4 - 11
14
9” x 4.7”
A20-26M
1130
42g
3 LiPo
4 - 11
15
9” x 4.7”
A20-22L
924
57g
3 LiPo
6 - 14
17
10” x 4.7”
A20-20L
1022
57g
3 LiPo
6 - 15
19
10” x 4.7”
Both series are supplied
with a comprehensive
mounting kit, comprising a
standard bulkhead mount,
a plywood mounting disc
and an unusual post mount
for a single mounting hole
in a bulkhead (extremely
useful for models with an
arrow shaft fuselage).
10
Amps
Cont. 15s
RPM/V
Propeller
The hardware supplied with A20 & A30 motors:
mounting screws, shaft circlips, shaft collet, various
mounts and a propeller adapter
E.F.-U.K.
The A30 has a 30mm diameter stator and additionally features EXtra Long versions
and a total of 9 different winds.
The Hacker A30-S, A-30M, A-30L and A-30XL with hardware supplied
Motor
Amps
Cont. 15s
RPM/V
Wgt
Battery
A30-28S
1140
70g
3 LiPo
< 15
25
9” x 6” to 10” x 4.7”
A30-22S
1440
70g
2 LiPo
3 LiPo
< 20
< 16
32
28
9” x 6” to 10” x 4.7”
7” x 6” to 8” x 3.8”
A30-16M
1060
105g
3 LiPo
< 22
33
10” x 4.7” to 11” x 4.7”
A30-12M
1370
105g
3 LiPo
< 25
35
8” x 3.8” to 9” x 4.7”
A30-12L
1000
145g
3 LiPo
4 LiPo
< 25
< 15
37
27
9” x 6” to 10” x 7”
TBA
A30-10L
1185
145g
3 LiPo
4 LiPo
< 29
< 20
40
30
9” x 4.7” to 10” x 4.7”
TBA
A30-12XL
770
180g
3 LiPo
4 LiPo
5 LiPo
< 25
< 18
< 14
37
28
22
13” x 8” to 14” x 7”
TBA
TBA
A30-10XL
900
180g
3 LiPo
4 LiPo
5 LiPo
< 30
<21
<17
42
32
25
12” x 8” to 13” x 6.5”
TBA
TBA
A30-8XL
1100
180g
3 LiPo
4 LiPo
<35
<25
45
33
TBA
Helicopter
E.F.-U.K.
Propeller
11
To drive these new motors Hacker have introduced the X-series of brushless
controllers. They are available in 5 versions with the ratings as shown below. All
are designed to operate on 2 - 3 LiPo or 5 - 10 NiCd/NiMH cells.
The Hacker X-7, X-12, X-20, X-30 and X-40 Brushless Controllers
Amps
ESC
Size (mm)
Weight
Current
BEC Load
X-7
29 x 23 x 9
10g (0.36oz)
7A
2-3 Servos
X-12
42 x 24 x 9
15g (0.53oz)
12A
2-3 Servos
X-20
42 x 24 x 9
16g (0.57oz)
20A
2-4 Servos
X-30
51 x 24 x 10
24g (0.85oz)
30A
2-4 Servos
X-40
81 x 28 x 10
45g (1.6oz)
40A
2-4 Servos
The prices for these new motors and controllers are not know at present, but
Hacker products are available in the UK from Gordon Tarling, 87 Cowley Mill
Road, Uxbridge, Middlesex, UB8 2QD (visitors strictly by prior appointment only).
Telephone and fax on 01895 251551, email sales@hackerbrushless.co.uk
You can also check out Gordon’s website at www.gordontarling.co.uk
Another previously unannounced item
available from Gordon Tarling is the
Alti 2 Altitude Data Logger (shown left).
Alti 2 is a small device, which can be
fitted into almost any model and will
store a record of the model’s altitude.
When you get home, the Alti 2 is
connected to your PC and the data
downloaded via the supplied software
(screen shot opposite). You can then
analyse your model’s flights and
performance. For example, if you are flying a glider and want to optimise the
model’s climb rate, the Alti 2 allow you to choose the best propeller for the job.
Alti 2 is powered by the receiver battery and could be connected to a spare channel,
12
E.F.-U.K.
which then enables flight markers to be entered into the data record in order to
make later analysis easier. Sample rate of the unit is adjustable from one sample
every 0.1 seconds to one every 6 seconds. Recording time of the standard unit
varies according to sample rate selected - from 14 minutes to 13 hours is possible.
Specification
Weight
9g
Dimensions
38 x 18 x 13mm
Memory capacity
Standard version 8180 records
BF version
32720 records
Power Supply
4.4 to 9.6 Volts DC
Current consumption
15mA
Resolution
0.5m
Max altitude
3000m relative to start height
No of flights (on/off cycles)
unlimited
Alti 2 is supplied complete with serial interface lead for connection to PC, with
software and full operating instructions supplied on CD. You will require Adobe
Acrobat Reader in order to read the instruction file.
Prices: Alti 2 Standard £ 99.95, Alti 2 BF (more memory) £ 119.95
Contact details for Gordon Tarling are on the opposite page.
E.F.-U.K.
13
Permagrit have recently added a couple of new tools to their range: Firstly are
the CB140 and CB280 Contour Blocks.
Also released is a Permagrit Sanding Block and various grades of Sanding sheets
design to fit it. The sanding sheets can of course be used with your own blocks to
obtain almost any sanding shape you require. If the sanding sheets are as durable
as their other products these could be a real winner.
Details on all Permagrit products can be seen and purchased online on their
excellent website at www.permagrit.com.
Alternatively they can be contacted on telephone 01529 455 034, fax 01529 455
514, email sales@permagrit.com or at Perma-Grit Tools, The Old Forge,
Osbournby, Sleaford, Lincolnshire, NG34 0DN.
14
E.F.-U.K.
This page features 3 new products available from Tony Hill of All Electric RC
(www.allelectricrc.co.uk).
Right is the 3D Piranha, a wild
performer! If you can fly a
manoeuvre, this model can
perform it!
Very light built up interlocked
construction and ARTF. The
best motor is a Vortex 28/26/1200
(or similar) on a 3S LiPo pack
around 900mAh.
This model kit is ONLY available from
All Electric RC and excellent value at only £39.99
Left is the Prodigy 3D, a Pattern - 3D
hybrid with superb performance!
The ideal motor is stated as the
Vortex 28/30/950 or similar sized
outrunner running on a 3S LiPo
pack of 1600mAh.
It is an ARTF kit of all built up
construction and has a 37½”
(95cm) wingspan.
You will see this advertised at
£124.99, but from All Electric
RC it is only £99.99
Below right is the new Pro-Peak Prodigy II charger. It has a variable rate charge
from 100mA to 5A and discharge between 100mA and 1A. It is capable of charging:
1 - 5 Li-Poly or Li-Ion Cells
1 - 14 NiCd or NiMH Cells
1 - 6 Lead cells.
It has a 2-line, 16 character
display and can do multiple
charge/discharge cycles.
The All Electric RC price is
£49.99.
See the All Electric RC range
on their website (above) or
you can contact them at
AllElectricRC@hotmail.com
or telephone 01782 788 778.
E.F.-U.K.
15
Electric-Planes.co.uk announce the arrival of the Mountain Models Etana, which
was awarded Best New Product at Southeast Electric Flight Festival (USA) 2005.
The Etana is a 44" (112 cm) wingspan aerobatic airplane with a wing area of 418
sq.in. (27 dm2) and is 45” (114 cm) in length. It’s large control surfaces makes it
3D capable. The Etana was carefully engineered to eliminate coupling in knife
edge allowing the less experienced pilot to knife edge with ease.
The Etana assembles quickly and easily. The laser cut kit is almost foolproof with
interlocking pieces designed with AutoCAD. Much of the fuselage and wings are
assembled before you start gluing. The wings plug into a carbon fibre spar and
the tail surfaces are airfoiled for good control response. The landing gear is prebent 6061 T6 aluminium and the wheels and pushrods are included with the kit.
Both a front firewall mount and a GWS style stick motor mount are provided. The
mounts bolt onto the fuselage, allowing easy swapping.
The Etana is designed to fly with a brushless motor capable of 150 to 200W with a
10” to 12” propeller. The prototype has flown well on an AXi 2808/24 propped to
pull 15A (150W) and has performed well. At these power levels, a 3S 2000mAh
LiPo battery pack is recommended. The flying weight is approx. 24 oz. (680g) plus
whatever battery pack you fit.
In addition to the kit, you will need two Naro Max BB servos, two Naro Standard
servos, two 6" (150mm) servo extension cables, two 12" (300mm) servo extension
cables, and two rolls of lightweight covering. If your transmitter does not have
two aileron servo mixing, you will also need a Y lead.
The price of the Etana kit from is Electric-Planes.co.uk £69.99. More information
on the Mountain Models range stocked by Electric-Planes.co.uk is available from
their website http://electric-planes.co.uk/ or telephoning 01229 824 740 (ask for
Mark - closed Thursday & Sunday) or email at enquiries@electric-planes.co.uk
16
E.F.-U.K.
Also recently added to electric-planes.co.uk is the Stevens Aero G-400x “Stella”.
Bill Stevens spent a considerable amount of time developing the unique aerodynamic
design of the Stella - every feature from the wing's transitional foil to fuselage
shape have been engineered to produce a model that is free of undesirable pitch
and roll coupling. This low wing design with intelligent fuselage shape allows for
efficient high and low speed knife edge performance. In fact Knife Edge loops are
standard fare in this models aerobatic diet.
Perhaps the most desirable feature of the Stella is in it's versatility. We all are
aware just how important a background in precision flying is when learning 3D
aerobatics. The Stella allows the novice pilot a solid platform that tracks large
clean loops, hammerheads, cubans, split S, point rolls, slow rolls, rolling circles,
Immelmans, humpty bumps, spins, and anything else you can dish out at it.
With the flick of your dual rate switch the Stella transforms into an aggressive no
compromises 3D machine to allow you to work out your harriers, hover, torque
rolls, blenders, waterfalls, parachutes, walls, etc ... without the need for re-propping,
mixing, or modifying the CG.
So far all we have discussed is Stella's flight performance. It seems unfair to end
here without telling you about the build performance. This kit flies off your
workbench in short order (2 evening frame up is average) thanks to the 100%
laser cut parts assembly. Each part is meticulously designed to interlock utilizing
the proven Stevens AeroModel Truss-Loc™ system.
They support their intelligently engineered model designs with clear concise plan
sheets backed by extensive photo illustrated instruction manuals...this is not a
build but a pleasurable assembly!
The Stella has a wing span and overall
length of 36½” (93cm) with a wing area
of 350 sq.in (22.6dm2). Typical flying
weight range is 14 to 16½ oz. (400 - 465g).
Unsurprisingly the Stella features
Aileron, Elevator, Rudder and Throttle
controls needing Naro servos throughout.
For a budget power system it can be fitted
with a GWS EPS350C or D motor set
with an 8-cell pack of KAN 650 and a
12” x 6” silent flight propeller.
For ultimate performance they
recommend a Tornado 2025-4200 with
5.33:1 gearbox, 3S LiPo around 1600mAh
and an 11” x 4.7” silent flight propeller.
The kit price is reasonable £60
E.F.-U.K.
17
The final new offering from electricplans.co.uk is the Tiny-X. The Tiny-X was
designed with a fully symmetrical airfoil and
to use the inexpensive GWS products allowing
you to fly aerobatics in confined spaces.
The kit includes 71 laser cut parts and a full
supply of Sig & Dubro hardware. 2 sheets of
CAD plans with written instructions allow
the Tiny-X to be built FAST & flown WILD.
The Tiny-X is capable of very tight low speed turns and for the more adventurous
types it will loop, roll and fly inverted. Full aerobatic flight times with a 7 cell
300mAh Nickel Metal Hydride battery pack are in the 7 minute range.
The model features a 27” (69cm) span and a wing area of 220 sq. in. (14.2dm2).
The flying weight is intended to be between 6½ and 7 oz. (185 - 200g). The
recommended motor set is the GWS IPS-DX2BB-A with a p” x 7” slowfly propeller.
It has Aileron, Elevator and Throttle control and requires micro radio equipment.
Recommended battery packs are 7-cell 300mAh NiMH or 2S LiPo under 1000mAh.
The kit is available for £45, see page 18 for contact details.
The Multiplex EasyGlider, electric and
sailplane versions, are
now available in model
shops. An ideal start
point for beginners to
RC. The electric model
is complete with motor,
gearbox & propeller. It
has a 1.8m (71”), 2piece, wing, GRP joiner
with Aileron, Elevator,
Rudder & Throttle
controls.
The Twin-Star II is
also now becoming
available in shops.
Like the original
1420mm (56”) span
but a two-piece wind,
lots of improvements
and moulded in EPP.
18
E.F.-U.K.
Readers’ Models
Your chance to show the members your model(s).
Above is the J. P. Special of Mike Moore (Hereford), which he has named the
“Raptor”. The model has a span of 1.56m (61½”), a wing area of approx. 24.2dm2
(375 sq.in.) and a flying weight of 1530g (54 oz.), giving a wing loading of around
63.3g/dm2 (20.7 oz./sq.ft.) and a wing cube loading of 12.8 (= Scale model).
Power is provided by 3 x Speed 400 motors in parallel with Graupner Grey 6” x 4”
propellers, a BEC controller and a 7-cell, Sub-C, 2400 mAh pack.
Initial “take-off” current is 30A, producing about 250W. This produces a thrust of
approx. 800g (28 oz.), giving a thrust:weight ratio of ~52%. After the initial surge,
the steady thrust at full throttle is 680g (24 oz.) and the thrust:weight is 44½%.
Mike says that at full throttle he gets Port: 10900 RPM, Centre: 11500 RPM and
Starboard: 11000 RPM. He has tried umpteen motors and can not get them to
synchronise.
Mike also says that it flies well none the less, with very little swing on take-off and
that can be controlled easily with the rudder.
(Editor: I think Mike is missing the point of multi-motor models. The whole idea
is that the motors on models and full size are never synchronised and one of the
best things is the beat pattern produced due to this. I wouldn’t worry about the
5% difference between the motors - vive la difference)
E.F.-U.K.
19
Above is Mark Christensen looking pleased with himself after another morning’s
flying on the sands in Wales. A July day with 3 miles of beach and no one around.
The other wise standard Twin-Jet “Blue Shark” has had Day-Glo covering added
to the inboard, front, upper surface of the wings. This greatly assists with reducing
the orientation problems that come with delta configurations.
Below and at the top of the next page are photographs of Fred Keegan’s LF1
Zaunkönig (“Wren”), from a plan by Phil Kent. At the bottom of the next page is
a photograph of the original aircraft taken at the RAeS Garden Party in 1950.
20
E.F.-U.K.
The Zaunkönig was designed by Professor Dr.Ing. H. Winter and was built as an
essay by the aeronautical students of the Technical University of Brunswick. It
first flew in April 1945 and was painted in German Grey-Green camouflage. The
flaps and slats gave a safe landing distance of 88 yds. (80m) and an unstick distance
of only 55 yds. (50m). The slats prevented the tips from stalling and the aircraft
could be flown semi-stalled at 31 mph (50 kph) with only the centre of the wing
stalled. It was intended to have a variable incidence wing and tailplane, but the
necessary fittings were never installed.
The original aircraft was fitted with a Zundapp Z9-92 4-cylinder inline air-cooled
engine rated at 51 hp at 2.350 rpm for take-off and driving a Schwarz two bladed
wooden propeller. It had a span of 26’ 4¾” (8.02m); length 19’ 10¾” (6.08m),
height 7’ 10¼” (2.38 m) and a wing area of 91.38 sq.ft. (8.49m2). The empty weight
was 553 lb. (251 kg) and maximum loaded weight was 776 lb. (355kg). The
performance was impressive with maximum speed 87.5 mph (141 kph); econ cruise
53 mph (85 kph); initial climb 562 ft/min (2.85m/s); approx ceiling, 12550’ (3820m);
range. 218 miles (350 km); take-off - flaps up 45mph (72kph), flaps down 31mph
(50 kph); Landing - engine off, flaps up 44mph (71 kph), flaps down 37 mph (60kph)
The model was designed for 5 channel control and an OS 30 FS. The latter has
been replaced with a 650 motor, 3:1 gearbox and an 8-cell 2400 mAh pack. It is
approx. 1:6 scale with a span of 53¾” (1.37m) and a wing area of 365 sq. in.
(23.5dm2). The flying weight is 4 lb. 9
oz. (2.07kg) giving a wing loading of 28.8
oz./sq.ft (88g/dm2). (Editor: The Wing
Cude Loading (WCL) is 18.1, which is a
little above the full size CL of 14.2 at
maximum load). The model is painted
with Humbrol No 25 Matt Blue with a
final coat of Plasti-kote clear Acrylic.
E.F.-U.K.
21
Let it Out!!
by John Thompson
Some years ago I went to the World Scale Champs in France and one of the fliers
from an Eastern bloc country had a Sopwith Triplane. The large ‘horseshoe’ cowl
contained a 25cc two stroke that had been fitted with a large alloy silencer.
The open end of the horseshoe is the only outlet for any cooling air entering the
front of the cowling, but in this case it was partly covered by the silencer. Now in
the colder climate of the Ukraine this may have worked, but in the 40° temperature
in France the engine just cooked, so he never completed a single flight all week.
It is important that air entering any engine installation should have an exit, and
that exit must be of bigger area to allow for heat expansion. Next time you are at
the Nationals look at a speed control-line model, they have close fitting cowl with
a slot at the front and a larger opening at the back. I have seen several model kits
both electric and IC which did not allow for this.
Recently I was flying my ‘Diablotin’ that also does not show any cooling arrangement
on the plan. It flies well on five LiPo cells, but on this flight the power began to
fade prematurely. Opening and closing the throttle made no improvement but
suddenly a stream of smoke appeared behind it!!
22
E.F.-U.K.
Recalling the horror stories about these cells, the throttle was closed and a rapid
arrival arranged. Approaching the model with caution the visible part of the
E.F.-U.K.
23
battery was in ashes, with soot everywhere. Nothing was burning so the broken
propeller was used to lever the bits out. The battery I am using consists of a three
cell pack with a two cell pack in series, and the latter had burst open, while the
former was still intact although somewhat charred.
Having witnessed last year the complete destruction of a large model whose LiPo’s
had been mischarged it was surprising that mine had survived, if somewhat
scorched. The answer seems to be ventilation. One cell of the pack had somehow
blown, but the arrangement of cooling air would seem to have dispersed the Oxygen/
Hydrogen gases before they could do much damage.
This conclusion was reached on internal inspection of the airframe as traces of the
sooty deposits could be seen along the line that the air would take. One is to the
underside under the wing, and the other through the cockpit.
My Devil pilot is covered in soot and now has a smoked canopy (see bottom of
previous page). Luckily I used a separate RX battery so kept control, and everything
still works, but there are a few burnt holes in the wing covering (shown above).
What caused it? I don’t know. The cells have been in use for a year, the packs are
charged separately on two ‘Prodigy’ Chargers at 1C, and the Torcman motor only
takes 20A static, well within the limit of the 2600s.
24
E.F.-U.K.
Fillip for a Filip
by Nick Fitton
Some time ago I wrote about ‘an incident’ I had in my Chipmunk, G-AOTR, when
confusion over the ‘You have control’ - ‘I have control’ convention nearly turned
me into a CAA statistic and my wife into a wealthy woman. Another bit of fun was
when I tried to do a Derry turn - not a Derry wing over, mind,. a Derry turn.
I knew the probable outcome so I started at 6000' needing fully half that to sort out
the resulting shambles. Derry turns are best left to the likes of the Extra, Sukhoi,
Harrier, Jaguar and the like, all of which have low roll inertia and eyeball twizzling
rates of roll. Or maybe just leave them to better pilots than me!
The reader may have the impression that much of my Chipmunk time was spent
in sheer terror. Actually most was pure pleasure, but just occasionally....................
RWY 04 abeam the port wing. I don’t like five mile VC10 approaches, especially in
a Chipmunk with a fifty year old Gypsy Major engine. The graveyard just before
the perimeter fence reinforces the point. The C of A has just been completed so the
engine will at it’s most unreliable.
Accordingly, the handling pilot has been told to do a glide approach via a descending
turn on to short finals. In well co-ordinated movements he reduces power to idle,
drops back to 60ish, selects flaps & trims- all this whilst holding a balanced turn.
Perhaps not the way it’s taught now, but the delightful handling of the Chipmunk
encourages it. Although I am PI, I have no worries, as this handling pilot seems
to know his stuff. It’s not easy landing an unfamiliar tailwheel aeroplane.
A little high, but better that than too low. Crossed controls into a gentle sideslip
whilst keeping the turn going, checking back to correct the nose drop. A nice coordinated turn now, full flap selected, speed reducing to fifty-five and I relax, looking
up at the top wing. I put my feet lightly on the rudder pedals because my knees,
damaged by forty years of Squash and Tennis, want to stretch. This simple act
probably saved our lives.
There are seminal moments in ones life - you know the kind of thing - holding your
new born for the first time, first solo, the Kennedy assassination etc. Now I
experienced another.
In the same instant as fright alarms the mind I sense the aeroplane go quiet, the
left wing teetering on the edge of ‘departing” as they say. I feel the stick hit my
right inner thigh, precisely where it shouldn’t be with the aeroplane in this attitude
and at this height. No time for the “I have control” bit - full top rudder, stick
central and easing forward (at this height one doesn’t ram the stick forward).
A spin, even an incipient one at this height will be irrecoverable - the aeroplane
has full tanks and my flame resistant flying suit won’t do much for me at 1200°C.
E.F.-U.K.
25
Feed in the power gently - one doesn’t ram the throttle forward either, as she has
the engaging habit of rich cutting. We’re flying again and I tease her towards the
runway. Much too fast to stop before the end, so full power & away we go.
The circuit is flown in silence as we realise that by rights we should be carbonised
on the 04 threshold. In relieved anger I fly a slipped, curved, glide approach as it
should be done, centralising the controls as the aeroplane settles on to the runway,
pedalling to counter the swing.
Why angry? Because I’m angry with myself, not the handling pilot. As PI I
should been monitoring his actions, especially at that critical phase of flight.
In silence we get out of the aircraft. I’m shaking. “Jesus Christ” says he, quietly.
He’s not swearing, he’s giving thanks.
Having recovered our composure we went aloft again that day, and he did it more
or less right. Most agricultural landings I experienced in the Chipmunk were at
the hands of pilots being checked out. Personally, I never did a really bad landing.
Anyone believe that?
I put in this little opener to capture your attention. If you are a modeller as well as
a full size pilot, remember the old canons of aviation wisdom: “Maintain thine
airspeed lest the ground arise and smite thee” and “All aeroplanes bite fools.” I’ve
lost six friends over the years because they thought they knew best.
Like my Chipmunk that near fatal day, my modelling career has taken a nosedive.
These days I have this irresistible urge to downsize, a better term being “downcash”.
I get more pleasure now trying to get a lot out of a little. I’ve been down the
‘chasing technology’ and ‘more Watts/lb.’ routes, and whilst it has been inspiring
(and expensive) I question whether it is aeromodelling in the Aeromodeller Magazine
sense of the word.
Surely one can get more fun per £ with simple Speed 400 models. Let me illustrate
the point. My Speed 400 Tucano flies for 8 minutes on an 8-cell KAN 1050 pack.
It is aerobatic and fast - a delight to fly in fact, and if you take care to build the
26
E.F.-U.K.
wing truly flat, the stall is a non event. It cost peanuts to make, doesn’t suffer
from hangar rash (too small), it doesn’t need to be assembled on site and can sit on
the car seat beside me.
Being so light it has little kinetic energy, so in heavy landings it suffers
proportionately less than it’s larger, faster cousins. Sheet construction translates
into low build times and ease of repair. What justification is there for an 85+%
efficient brushless motor and associated ESC costing maybe £60? Ditto LiPo. A
45% efficient Speed 400 at £3.95 produces a fast pleasant model aeroplane, which
is what it is all about.
(Editor: Some people like to have more fun per £, for others they just want to go
even faster and for longer - Brushless & LiPo is the best way to achieve this..)
I have always found it relaxing watching birds of prey and seagulls soaring. I
especially like watching them hovering stationery on a strong wind, and on landing
when they mimic aircraft in almost every way – actually the other way round,
except that with real aeroplanes the feathers don’t rise at the stall!
So I keep coming back to powered gliders. Having assembled the Filip 600 Sport,
I liked the build quality of the RCM Pelikan kits and so the logical choice was the
Filip 400 Aileron.
In keeping with the downcashing philosophy I want to use the same packs, motors
and ESCs for most of my future models. This is bad news for suppliers. Mr Emms
will however be pleased to learn that I intend building another Filip 600 Sport or
similar, when the spirit moves me.
The level of performance required for the Filip 400 meant the choice of power train
was never in doubt. It had to be geared, and it had to be the Cosomotech epicyclic
gearbox. From the flying weight and wing area I calculated the stall speed (4.4*
Sqrt wing loading in ozs./sq.ft.) as 13 mph, and hence the pitch speed at 26mph,
which is 2 x stall speed which is OK for a powered glider.
(But not for a Speed 400 aerobatic model when I want 3 x stall speed) This gave me
an RPM figure, hence the prop pitch. MotoCalc gave me the prop thrust, which I
wanted to be not less than ½ flying weight.
Building the Model
At about 23 ozs. flying weight the Filip 400 is not in the “Highlight” and “Simply
the Best” league, but it comes close and is capable of winning competitions.
In Northern Ireland, and especially in the West of County Tyrone we experience
windy conditions a-plenty as evidenced by the number of wind farms, so maybe
the ultra light Highlight and STB are not really suitable for our conditions.
(Update. Since the bulk of this article was written I have come to the view that
the Filip 400 is also to light for N Ireland conditions, hence my intention to buy a
Filip 600 Sport).
E.F.-U.K.
27
The RCM Pelikan Filip 400 as designed. This photograph is of another Filip 400 as
Nick didn’t provide any photographs with his article.
The Filip 400 aileron is, not surprisingly, the aileron equipped version of the “basic”
two-channel Filip 400. It is available with either a V or T tailplane, and has an
optional air brake- actually a spoiler. Rather strangely, the wing tip dihedral of
the two channel version is retained for the aileron version, albeit at a reduced
angle. More on this later.
Puffin’s mail order service deserves special mention. I live in Omagh in the far
west of N. Ireland, but if I ring my order through at a reasonable time of day it
usually arrives on my doorstep the following morning. On one occasion I rang my
order through at an unreasonable time and it arrived with the early morning post.
Flawless service - thanks Puffin.
Less appreciated was the fact that the sticky tape used to stop the components
from rattling round in the box had stuck to the glass fibre fuselage, and it was hell
to remove! The instructions start out well but rapidly head south. I got the
distinct impression that the ailerons had been added as an afterthought, and that
the instructions had been hastily and minimally revised to suit.
Fuselage
First job was to mate the gearbox to the motor. You must get this 100% right,
first time, no compromise. The pinion is a tight interference fit on the shaft of the
MIG 400 motor. Clean the shaft and pinion bore to remove all traces of oil. Using
a pin apply a high shear strength adhesive to the pinion bore, working from the
top and wetting the entire circumference.
28
E.F.-U.K.
Be careful to apply only the bare minimum because if you overdo it excess adhesive
might run back into the motor bearing. I wrap thread around the shaft at the
bearing to absorb any excess adhesive.
Making sure everything is square press the pinion on to the shaft (careful!) ensuring
it is placed in the exact position to ensure full length engagement with the planetary
gears. To achieve this I made up a simple jig using squared graph paper.
Push the pinion on in small increments because you do not want to have to slide it
back and forwards along the shaft to find the correct position, which would require
the use of a pinion puller and lots of swearing.
Remember that the adhesive is curing rapidly from the moment air starts to be
excluded from the gap. Allow it to cure for as long as you can before subjecting the
bond line to any load. At a guess it’s probably near full strength after a day, but I
don’t load it at all until the model is ready for pre first flight power checks.
The motor gearbox combination is mated to the ply nose former and test fitted to
the fuselage. RCM Pelikan have cut the nose to the correct angles of down and
side thrust, but this fact is not stated in the instructions. Neither can I decipher
that point in the instructions where they attempt to explain how to mount the ply
former in the nose - I got the bit about cleaning / sanding the inside of the nose at
what will be the bond line, but after that I got lost.
My own technique is to clamp the motor/gearbox/former unit to the nose using the
spinner as the clamp, allowing it’s back face to mate accurately with the nose
edges. This technique achieves a virtually perfect fit.
RCM Pelikan supplies a ventilating spinner and to get the entrained air to cool the
motor I drilled a number of small holes around the periphery of the nose former.
Now comes the fun of fitting the wing bolt mounting. My first instruction is to
throwaway the instructions. Unless you are ET neither you nor I have 10" long
fingers. You have to cut a hole at the point where the wing seats on the fuselage,
but the instructions don’t say this.
This cut out also facilitates fitting the elevator and rudder servos, which you will
probably want to mount under the wing centre section. This is also where the Rx
has to go because it has to receive the wing servo plugs. A useful benefit is that it
places the Rx a long way from the ESC, in my case a Rondo.
Mounting the elevator and rudder servos in this position allows the battery pack
to be Velcro fixed to the floor thus permitting plenty of room for CG adjustment.
To achieve adequate, accurate and repeatable control surface movement, you have
to bond the control rod outers to the fuselage sides, and over a considerable length.
You will not enjoy this job. I managed it by placing a cautious finger on the outer
and pinning it to the fuselage side (the outer, not my finger), then ran medium
cyano along the outer.
E.F.-U.K.
29
This can have several outcomes: (1) the outer will be well attached with a cyano/
skin gap-filling compound. (2) if you are really clumsy the inner will be permanently
internally bonded to the inner surface of the outer (I like that!) (3) you and the
aeroplane will be inseparable and (4) the result will be as hoped for, which I what
I achieved. Another way of doing it is to use thick discs of blue foam pushed down
the fuselage.
Tailplane/rudder
Rudder is easy and needs no comment.
The tailplane is fixed to the fuselage using the “captive nut bonded to a drilled
hardwood insert, epoxied into the top of the fin” system, but using the bits supplied
leads to inaccurate location and high bending stresses in the nylon fixing bolt. My
system uses a piece of ½” square soft balsa strip (ex Twin-Jet spine), skinned on
one face with 1/32" ply and sanded to an approximate “D” section.
This is squeezed into the top of the fin and bonded in place with cyano. With the
tailplane temporarily in place and accurately aligned the hole can be drilled. The
beauty of this system is that the soft balsa gives slightly, allowing the captive bolt
to “find it’s own position” in relation to the bolt, thus relieving stresses.
Filip advise that the forward end of the tailplane be located with a dowel or something
(I had virtually abandoned the instructions at this stage) but a small self tapping
screw directly into the fibreglass is easier and better.
The Wing
The only jobs here are (1) install the servos, (2) fit the central locating dowel and
(3) attach the wing tips at the correct angle. For (1) I used the masking tape/
cyano method, (2) no problem and (3) - a doddle you might think, but because the
tips are set up at an angle and swept back the spruce spar cannot be continued
across the discontinuity.
RCM Pelikan’s solution is to epoxy a piece of loose fitting spruce across the gap. I
did this with trepidation, as I don’t like discontinuities in wing spars.
To carry the aileron cables there are tubes placed in the tips and main wing
panels. To make your life a little more difficult the two ends do not line up, and if
you get epoxy in there as well you are b**gered vis-a-vis pushing the cables along
the wing. Work out your own salvation!
Electronics installation
No real problems here. Just a comment on my choice of ESC. I elected to use a
Rondo unit, available ex my stock, thus maximising fuselage space and minimising
cost. This ESC can only drive three servos and I had four, indeed five if I chose to
use the mid wing spoiler. This latter problem was eliminated by opting to go for
spoilerons.
30
E.F.-U.K.
My thinking was that if this ESC were installed in a high speed aerobatic model
with three servos, it would not be electrically overloaded if installed in a 4 servo
gentle model like the Filip 400. I’m sure ESC designers build in a fiddle factor,
and so far I have had no problems.
A comment here on the Rondo ESC. The 3 leads leading to the Rx are soldered
directly into the PCB and as such produce a weak joint, intolerant of vibration,
bending etc. I had one of the leads let go and it was most difficult to solder it back.
Rx sits aft of the wing bolt, thus putting it a long way from the ESC. The battery
pack is Velcro attached to a false floor epoxied into the fuselage, thus allowing
ample room for CG adjustment and easy removal.
Flying
First flight was scary. The model went into a marginally controllable roll to the
right, controllability improving as the speed built up. I was glad to have the
rudder available otherwise it would have been a bin bag job. The problem turned
out to be a washed in warp in the left wing: bearing in mind RCM Pelikan’s
quality I had assumed the wing would be true. Silly boy.
A session at home with the smoothing iron eliminated the warp, and the control
surfaces were set up with double deflection. The right rolling tendency was
eliminated, but the roll rate was still very soggy, rudder being necessary to achieve
satisfactory response. Maybe this is a good thing hones one’s flying skills and all
that sort of thing.
Pitch stability and response were satisfactory, as was the action of the spoilerons,
especially with some down elevator mixed in.
Climb rate is excellent, prompting some club members to ask what type of brushless
motor I am using: the answer “a £3.95 ferrite” has the desired effect. I conveniently
leave out the bit about the £50 gearbox- well, they didn’t ask, and with a 10” x 8”
propeller poking out of the front it should have been obvious: can’t really expect too
much intelligence in I/C types!
Aerobatics reveal the ability to loop from straight and level but rolls of any type
are a non-starter. It won’t spin either, which is probably a good thing as a VNE
dive might result. I once did this spinning a Rollason Condor, the recovery ending
up past the vertical and in excess of VNE - scary!
Development
I came to the conclusion that the sluggish roll rate was due to the high degree of
stability conferred by the upturned wing tips. Additionally, because the ailerons
are set into the tips the rolling moment produced by aileron deflection would lower
than would be the case were the tips flat (think about it).
My solution was crude. I sawed the tips almost completely through, cracked them
downward and pinned them flat to align with the main wing panel. The resultant
E.F.-U.K.
31
gap between main panel and tip was packed with balsa wood dust and thin cyano
dripped on. If you do this at home wear a mask and deactivate the smoke alarm.
The result is a slight improvement in roll rate but it’s still a bit Queen Mum for
my liking. I took the opportunity to re-cover the entire wing with red Airspan
because I hate the “starved horse” look prized by so many modellers. I also feel the
original Oracover exerts too strong a shrinking force on the lightweight structure
and that this is what caused the wing warp.
However, whilst out flying recently I experienced severe wing tip flutter followed
by detachment, whilst pulling gently out of a loop. I was sufficiently close to
observe that the wing tip appeared to be in a resonant twisting mode, leading me
to suspect that the use of Airspan had compromised rigidity.
The bond line between the main wing panel and tip was OK, but it seemed more as
if the structure had shattered. I intend re-covering with good old tissue and dope
to restore stiffness. I also suspect that lack of rigidity might contribute to the poor
roll rate, the wing tip twisting in response to aileron movement.
Perhaps aeroelasticity is too grand a concept at Filip 400 speeds! A few closing
comments. I dislike RCM Pelikan’s choice of colours, (yellow tips and spoiler
plate, red main wing, blue canopy), so my model is now unashamedly red, white
and blue, with the Union flag on it’s tail.
I dislike even more the instruction manual. RCM Pelikan needs a serious rethink
on this one.
The Filip 400 Aileron is a delightful model when used in its intended role i.e. a
summer day soaring. High speed passes with pull ups are not a good idea, and
neither are aerobatics. If you want that go to the Highlander, Pelikan, or 600
Sport and see John’s eyes light up!
Looks-wise it is quite superb, especially in my non-dihedral version. Gliders with
turned up tips look a bit toyish to me.
Here is the Filip data:Span:
1.6m (63")
Current:
8A
Weight
680g (24 ozs.)
Motor volts:
8.5 V
Area:
29.2dm2 (453 sq. ins.)
Power load:
45 W/lb. (input)
Loading:
54.75g/dm2 (7.6 oz./sq.ft.)
Prop. RPM:
4700
Power:
MIG 400 (Puffin)
Pitch speed:
35 mph (56 kph)
ESC:
Kontronic Rondo 400
Thrust:
50% of weight*
Gearbox:
Cosmotech epicyclic 4.5:1
Stall Speed
13 mph (21 kph) (calc)
Propeller: 10” x 8” Aeronaut folder
Rate of climb: 750 ft/min (3.8m/s)*
Pack:
* = MotoCalc prediction
32
8 x KAN-1050 NiMH
E.F.-U.K.
The Chester Electric Fly-In at
the Roodee 2005
by John Thompson
Sunday June 19th dawned hot and sunny so the signs were good for this annual
event. My driving into the City was more careful than last year when a speed
camera caught me out. The Roodee was humming with activity and it was reported
that 250 cars were parked, fortunately for us fliers, not all contained models.
The flying soon got under way with a wider variety of aeroplanes than you would
get at the average IC meeting. Unfortunately I decided to get some flying in the
morning and take pictures later in the day, not a good idea as you will see.
Several models caught my eye including a Latecore flying boat, Quadriplane, and
even a Wright Flyer made a brief hop. One of my favourite aircraft is the DH 108
Swallow, and Richard Jones’s of the ‘Plane Crazy’ club, had his scratch built one
which performed well on a Mega 22/30/2 and 16 cells. His unusual Horton 9C
sported two similar Megas and 32 cells to fly in a convincing manner. Both these
impressive bungeed models flew regularly during the day.
E.F.-U.K.
33
My Grumman Cougar from the Airworks kit had made its first flight (in my
hands) the week before and the foot released bungee had behaved impeccably,
although landing a DF model without elevator got the adrenaline going.
34
E.F.-U.K.
Sods law however came to the fore, and apart from the line breaking and whacking
my leg, somehow it got caught in the LE causing the model to slew over, so aborting
the flying. Later the small RX in my Micro-Bipe suffered from the proximity of all
the TXs and it got slightly damaged as well.
Unfortunately early afternoon brought thunder, lightning and hailstones, so flying
was suspended and quite a few families set off home. Later it cleared a little and
the prize giving was brought forward. In the past prizes have been awarded for
various categories, but this year
only one was given.
Bill Macleod was thrilled when
on his first visit to the Roodee
he was awarded the prize for
‘Most Impressive Model’ with
his ‘Pou de Ciel’ powered by a
Typhoon 15 on 3S2P 2400 LiPo
cells and 7” x 4” propeller.
A raffle followed with all the
Traders generously donating
items, and BEFA giving a free
years membership.
All in all a good days flying,
thanks Chester for another well
organised event.
E.F.-U.K.
35
A-10 Warthog
by Ivan Goodchild
Having designed and built several large scale electric models including Sally B the
B17, we were looking for an unusual model for our next project. Tony had already
built his excellent 5.2m (17’) Lancaster and the bomber scene was now well served.
Whilst attending an LMA event at Duxford, we found a book by Peter Smith on
the history and development of the A-10 Thunderbolt affectionately known as the
Warthog. A trawl through the various aviation web sites indicated that the only
models currently available were either very small GWS foam types, a small combat
models version or a large Turbine model made by Mobira in the States.
Having acquired a copy of the basic design drawings, 1/6th scale would produce a
3m (9’ 10’) wing span, 2.8m (9’ 2”) fuselage, which would be in keeping with the
size of models suitable for displays. The complete design was then evolved on the
CAD program using the interlocking technique and presented to Ian Hull at SLEC
to CNC all of the parts required for the model. The basic design being completed
over a 6 week period to the following specification.
Wing Span
3m
Fuselage length
2.8m
Wing Chord:
0.6m inner panels,
Dihedral:
7° on outer panel to anti stall tips with 3° washout.
Wing section:
Semi-symmetrical with under camber
Wing incidence:
+2°
Tail plane incidence
0°
Ailerons:
Differential 25° up, 15° down
Split Ailerons:
60° up, 40° down
Fowler Flaps
0 to 40°
Slats:
Inboard - for use at high angles of attack.
Elevator:
45° up, 30° down
Twin Rudders:
±45°
Undercarriage:
Retracts with 9” ground clearance
Wheels:
Main 5” (12.7 cm), Nose 3½” (8.9 cm)
Information coming to us from ducted fan sources indicated that we would need a
larger elevator than for an equivalent prop aircraft for this model. The geometry
of the fans, wing and tail plan coupled with the overall balance would require fine
tuning so a detailed C of G design and calculation was necessary. Jan’s recent
article is spot on in this respect and the position can be very accurately projected.
36
E.F.-U.K.
The overall weight of the model was set at a maximum of 12kg (26½ lb.) giving
around 27 oz./sq.ft. (82 g/dm2) wing loading. At this design weight we needed a
thrust to weight ratio of at least 0.5 to 0.6. This required the use of the latest
technology for the fans, motors and batteries. Aeronaut had just had designed a
new Turbo 4000 120mm fan which their tests showed would generate between 35
and 42N (7.9 to 9.4 lb.) of thrust.
Discussions with their designer indicated that the best motor would be a Plettenberg
300/40/A2S 8-pole motor powered by either a 9S or 10S LiPo pack. Maximum
current draw would be between 40 and 55A for take-off and then throttled back to
under half for flight.
Further discussions were had with Thunderpower in the States and we settled on
their 5S3P 6000mAh packs for the batteries. We therefore had an available thrust
of 70N+ (15+ lbs.) giving us the ratio we sought with a maximum flight time of
around 15 mins. In this regard we are indebted to Gordon Tarling for his assistance
with the manufacturers.
Our past experience with the standard retract systems available suggested they
were less than adequate for this model and we settled on the Eurokit Pro Line
system which has proved very good indeed. In addition Tony at Unitracts made
the oleos for us.
The A-10 was designed to be highly manoeuvrable at low level and low speed with
an apparent low speed take off. The design therefore reflected this criteria to
demonstrate its low speed, low level, capabilities as we were not aiming at an F-15
flight envelope
E.F.-U.K.
37
The
aircraft
was
designed around an
internal interlocking box
structure into which all
the equipment was fitted.
The fuselage shape being
conventionally
constructed around it
using balsa, liteply &
birch ply with carbon
reinforcing as required.
The wing was made in three sections the inner which housed the retracts, Fowler
flaps slats and bomb release gear, and two tip panels. The whole model was
covered in 27 g/m2 (0.8 oz./sq.yd.) glass cloth from Cherbourg models our usual
light and ding proof method and sprayed with matt enamel from Humbrol. The
colour scheme to be international camouflage as per 81st TFW at Bentwaters.
All metal servos are used throughout. The ailerons, split ailerons, elevator and
rudder are Multiplex digital. The flaps, nose wheel steering and slats are Hitec
HS85MG, and the bomb release, Supertec mini. The radio system used is a Futaba
9FC transmitter with 9ch PCM receiver with 2 x 1700mAh NiCd 6V batteries.
The test flight was undertaken at RAF Honnington on a glorious sunny day with
wind of 12 knots 30° off the main runway. We kept it on the runway for about
60m, to assess the ground speed and steering slight up elevator and off she came
true scale. Like all large models with a large wing area she was very stable
requiring very little control input to fly with a few small trim adjustments.
After a few circuits we lined up on finals decreased the power and she virtually
glided down the glide path. We used the split ailerons to slow her down on the
runway, but we will fit some electro-brakes from Kavan in due course. We used
2.8Ah from the batteries for the test flight with a drop of just 0.3V per pack.
Since the test flight we flew it at Bickley up the grass hill into a 20 knot wind and
it lifted off in about the same distance. We met Klauss at the event and he advised
on a mod to the ducting for the fans. We have adjusted the tail cone to give
slightly less than the 90% swept area recommended and have increases the air
pressure by around 15%.
At the time of writing we have not
retested but expect the straight line speed
to have increased.
For anybody contemplating a large
electric model - please make it. They are
a joy to fly and much easier than the
small models
38
E.F.-U.K.
The 3rd Annual PANDAS
Electric Fly-In, 17th July 2005
(PANDAS = Pontefract and District Aeromodellers)
by John Thompson
This event is becoming more popular every year, and the hot weather brought out
33 flyers and a host of spectators. Trade support from Concept Models, FVK, RBC,
plus Mugi was welcome, together with a couple of “car booters”, and all provided
items for the raffle. Thanks Lads. In fact one well known trader, who was booked
in at the NEC on that weekend, had asked me if we could change the date so he
could attend.
The new PANDAS tent was put to good use, this time to keep the sun out, and a
free barbecue laid on by the good ladies Barbara and Kath under an awning for the
same reason. Unusually for this site the grass had been cut short so take offs
were easily accomplished.
Club Chairman Trevor Jones booked in all the TXs and started the proceeding off
with the usual warnings about flying on a site with public access.
Most of the flyers had brought at least two models, and such a variation you would
not see on the average IC meet. Several flying boats were searching for water,
including a couple of twins, and unusually didn’t find any. Multi engines were in
abundance, from a B36 down to a couple of Mosquitos, electrics make it so much
easier with no asymmetric problems.
Unknown Flying Boat
E.F.-U.K.
39
A large Lancaster that took 1st in Scale
Fun flyers large and small with big props were everywhere, cavorting and prop
hanging in the light wind. The cross section was so vast it would be difficult to
highlight individuals.
With the calm conditions and hot sun we had ideal conditions for a good days
flying and we made the most of it! With my lesser involvement in the running I
was able to make seven flights with three models. Would have been four if an
aileron servo had not stripped in transit.
The event was so easy going that later the TX control was self-service and everyone
waited their turn without a quibble.
Second in scale, and in my opinion best model, was a superb Aichi Val from the
American Skyhawk kit. Built and flown by David Muir of Harrogate. Adequately
powered by a Twister 60 driving a 14” x 6” CAM propeller from 4 x 3200 Flightpower
LiPo packs, it is finished in tissue and dope with David’s usual immaculate detailing.
Pete Nicholson and Alan Wales did a synchronised take off with their Hangar 9
ARTF Mustangs, and put in an impressive flying display. Powered by AXi 4130/
16s, they differed in that Alan used 20 x GP3300s while Pete had 6000 mAh LiPo
to swing the 16” x 10” propellers. Alan’s had also been re-covered to an all silver
finish and was placed 3rd in Scale.
The highlight of this year for PANDAS Members was the Eric Johnson Trophy, a
superb silver salver resting on a stand made by Pandas member Peter Waite.
Eric is one of the founder members and over a few decades has probably taught
dozens of modellers to fly. Unfortunately he has been in poor health for a while,
and in fact was taken into hospital the day before for more tests, so was unable to
attend. Gladly he is now out and about again. The award is in recognition of all
40
E.F.-U.K.
Mark Haig’s Aichi Val - 2nd in Scale
his efforts over the years and is for the best Pandas member at this event. Eric’s
son Kevin kindly accepted the trophy, and presented it to Tony Waite for his
immaculately built and flown electric conversion of a ‘Wot Four’.
Awards of bottles of wine were made in the usual categories, though regrettably
the corresponding certificates had gone missing. If the winners contact me, I will
get duplicates sent on. All in all an excellent, easy-going, days flying.
Pete Nicholson’s and Alan Wales’s Hangar 9 Mustangs
E.F.-U.K.
41
Above is the Hangar 9 Mustang of Alan Wales
Below is Pete Nicholson’s, Hangar 9, F4U Corsair
42
E.F.-U.K.
Top is a model of the Cri Cri by Mark Haig
Bottom, Tony Waite with the Eric Jhoston Trophy presented by Kevin Johnson (behind)
E.F.-U.K.
43
Above: A line up of the Warbirds in attendance
Below: The traders, spectators & control tent (with good separation) on a glorious day
44
E.F.-U.K.
Some LiPo experiments
by Peter Vivian
As a complete newcomer to Electric Flight I found essential reading of opinions
from books / articles etc., conflicting and confusing and I became convinced that I
should carry out my own experiments with charging, using and re-charging of
LiPo batteries.
I used all Hi-Energy LiPo batteries from the same dealer, purchased the same
day, one a 2S2P pack giving a nominal 7.4v and capacity of 4000mAh and the
other, made up of identical cells, a 3S2P giving nominally 11.1v and 4000mAh.
I labelled the cells of the 2S2P pack A, B, C, and D, whilst I labelled the 3S2P cells
E, F, G, H, I, and J. Cells A and C were in series and in parallel with series pair
B and D. Likewise Cells E, G and I were in series and in parallel with the series
string of cells F, H and J.
I connected C//D to E//F to give the series / parallel connections I required for a
nominal 18.5v 4000mAh pack. Positive output of the battery was then of course
taken from A//B and negative from I//J, as shown.
I discharged at different rates running an AXi 4120/14 motor at different speeds
for current drain and propeller experiments etc., and hence different currents
between 8 and 32A were used until the motor stopped (Editor: hopefully using a
suitable voltage cut-out to prevent damaging the cells).
I did this 4 times, recharging the 7.4v battery and the 11.1v battery separately at
1C on a Mercury EX charger, Lithium setting. I checked the off-load voltage after
each discharge and it varied between 16.8v and 17.3v.
E.F.-U.K.
45
Some say that 3.0v per cell is said by some to be OK, others say 3.5v minimum so
I should have obtained 15.0v by some standards (which I did) or 17.5v minimum
according to others (which I did not), and hence according to some I had overdischarged apparently. (Editor: All the LiPo manufactures I’ve seen agree that
the minimum off-load voltage is 3.0v/cell, I don’t know where the 3.5v/cell came
from. They also agree that the minimum on-load is 2.5v/cell at the rated
discharge, which should give 3.0v/cell once off-load).
After the 4th set of experiments and hence four discharges and 3 charges I carried
out the balance checks advocated by Andrew Gibb in his Lithium Battery book.
This has to be done by disconnecting both the parallel connections at points X and
Y and the series connector (above) then measuring each cell individually, and
found the following:
Measuring the cells open circuit i.e. off load, the 2S2P battery gave figures for
individual cells:
Cell A
3.11 v
Cell B
3.44 v
Cell C
3.13 v
Cell D
3.43 v
All OK by some standards, but a 10% difference is too great according to others.
The 3S2P battery gave cell figures
Cell E
3.60 v
Cell F
3.56 v
Cell G
3.56 v
Cell H
3.56 v
Cell I
3.58 v
Cell J
3.57 v
These latter were good, but why were these cells so different from Cells A, B, C and
D when they were being used in series/parallel, all together at one time?
(Editor: There will always be resistance and capacity differences between cells
and series strings of cells. When packs are used in parallel the cells with the
lowest resistance will discharge at a faster rate than those with higher resistance.
Further higher capacity cells will have a higher terminal voltage as they have
more remaining capacity. Thus you get differences in terminal voltage across
each of the cells in a pack regardless of shape. Where packs are made of selected
“matched” cells the differences will be much smaller and the problem are reduced).
However, I recharged. I charged each cell of the 2S2P battery individually, at 1C
in accordance with the book, and had the following results:
Cell A
1515
3.1
4.15
Cell B
1715
2.1
4.15
Cell C
1674
2.8
4.15
Cell D
1741
2.2
4.15
mAh
hours
volts
(Editor: I am amazed that it took 2.1+ hours to charge these cells at 1C. Even
allowing for the ramp up in voltage, and the decline in charging current once the
maximum voltage has been reached, I would expect a maximum charge duration
nearer 1.5 hours. It looks more like you are charging at 1A and not 1C. Interesting
that your cells are not getting to the normal 4.20v)
46
E.F.-U.K.
After resting for 24 hours the individual cells gave:
Cell A
4.06 v
Cell B
4.08 v
Cell C
4.08 v
Cell D
4.08 v
Excellent
However, the 3S2P battery I re-charged in parallel pairs, again at 1C. This is a
tricky operation requiring some considerable soldering experience and not to be
undertaken lightly, the LiPo cells are very easily turned into scrap. In essence
each pair of cells, E/F, G/H and I/J has to be electrically isolated from the other.
The results were:
Cells E+F
3504
4.0
4.15
Cell G+H
3487
4.0
4.15
Cell I+J
3482
4.0
4.15
mAh
hours
volts
After resting for 24 hours the individual cells gave:
Cell E
4.09 v
Cell F
4.09 v
Cell G
4.08 v
Cell H
4.09 v
Cell I
4.08 v
Cell J
4.08 v
(This operation is much
simplified if the packs are
soldered in a more suitable
pattern to start and
balancing leads are soldered
to each cell terminal and
then fitted to an appropriate
connector.
Most LiPo cells are now
supplied with balancing leads
which saves that effort. For
balancing leads to function
correctly the cells must be
wired in parallel first and
then in series as shown.)
So, finally a maximum variation over the 10 cells of 0.03v, some 0.7%, satisfactory
I think but note that of the cells of battery 2S2P the Cells A and C took much
longer to re-charge - because they started off at a much lower voltage presumably.
But how did those cells get so much lower when in use with 8 other cells? I can
only think that they were different as supplied perhaps? Remember, the 3S2P
cells were re-charged in parallel pairs so should take twice as long - they took a bit
less actually (Editor: If charged at 1C they should take the same time as when
not connected in parallel. Remember 1C for a 4000mAh pack is 4A. BEFA advises
that a maximum of 0.75C (3A in this case) should be used when charging paralleled
packs as there will be differences between the individual cells).
E.F.-U.K.
47
Next, I ran the AXi motor at a steady 5250 rpm with a 12” x 10” propeller (50 mph
equivalent) and it drew 11A (just under 3C). After about 15 minutes the speed and
current dropped a little, 10A & 5000 rpm (presumably the voltage fell off) so I
raised rpm back to 5250, which again drew 11A. I had to throttle up slightly every
half-minute or so in order to maintain 5250 rpm and 11A and after 20 minutes the
motor stopped. This was equivalent to 3667 mAh, about 90% of nominal - pretty
good I think. (Editor: New Kokam cells typically deliver 100% capacity at cut-off)
After cooling the pack for ~5 hours I separated the cells and checked them off-load:
Cell A
2.71 v
Cell B
3.07 v
Cell C
2.89 v
Cell D
2.80 v
Cell E
3.53 v
Cell F
3.49 v
Cell G
3.34 v
Cell H
3.47 v
Cell I
3.42 v
Cell J
3.48 v
Wow, all the experts tell me never to discharge to below 3 volts or even higher!!
(Editor: The reason for the limit is that the cells can be permanent damaged
when discharged to too low a voltage. You may not notice immediate problems,
but it is likely that the cell capacity may reduce because of this.)
Now, A, B, C, and D make up the 2S2P, 7.4v, battery and the others make up the
11.1v battery. Why did the 2S2P battery discharge to such a low level, a dangerously
low level? How was it possible?
(Editor: As I commented earlier this is probable due to differences in capacity (C)
of the cells being used despite them being marked the same. Cells from different
batches can be considerably different in actual C value. The problem could be
being masked by having 2 lower C cells and 3 higher C cells. The lower C cells are
exhausted, with voltage dropping fast, but the higher C cells still have charge
and maintain a high voltage. The controller only sees the total voltage which is
being “propped up” by the higher C cells. The best way to check is to charge and
then discharge the cells individually. This will show the true C of the cells (at
that discharge current) and they can be assessed without the associated issues)
Anyway, I recharged them all in parallel pairs and obtained the following data
Cells A+B Cells C+D
3450
3626
5.5
4.0
4.15
4.15
Cells E+F
3539
3.7
4.15
Cell G+H
3608
3.5
4.15
Cell I+J
3621
4.0
4.15
mAh
hours
volts
However, after over-night resting and separating the cells I checked each one
individually and had the following results:
48
Cell A
4.08 v
Cell B
4.09 v
Cell C
3.97 v
Cell D
4.09 v
Cell E
4.09 v
Cell F
4.08 v
Cell G
4.09 v
Cell H
4.09 v
E.F.-U.K.
Cell I
4.09 v
Cell J
4.09 v
So cell C was very much the odd one out. However, I recharged just that one and
it took 95 mAh and ended up giving 4.08v the next day.
Interesting to note that the A//B pair took by far the longest to charge up and took
in far less Ah. Is there a problem with cell C? Higher than usual internal resistance
perhaps? They were all brand new. If I had not bothered to check individual cells,
if I had just recharged as I had with the first 4 discharge cycles because some
"experts" tell me that to discharge to no lower than 3.0v per cell is OK, i.e. 15volts
from 5S2P, I could have been another LiPo statistic.
One of the most important results of these experiments is that after a theoretical
20 minute flight it took in total 21 hours to totally recharge the battery to a
strictly correct balanced standard for LiPo cells, not the about 2 hours some "experts"
tell you. Not the way to get plenty of flying time unless you spend a lot of money
on very many battery sets - at about £150 a throw.
(Editor: Using a correctly wired pack and a balancing charger (or balancing
circuit of some kind) the charge time is no longer than a conventional charge, i.e.
about 90 minutes. There are several suppliers that make dedicated LiPo balancing
chargers, but these are relatively expensive as they are dedicated. The cheaper
option is a LiPo balancer that is connected whilst using any LiPo charger. These
limit the voltage across each cells ensuring that they all get to the same 4.20v at
the end of charging. Currently I know of units by Orbit and Thunder Power, but
there may be more units out there, I sure there will be soon if not now.)
Now, if I change to NiMH then I understand from Andrew's writings, if I interpret
them correctly, that I can re-charge an 18v battery in one hit in about 1½ - 2
hours. More weight, more bulk, but a lot less money so 2 or 3 packs would not be
unreasonable, and a lot safer and less complex - as long as I can fit them in the
aircraft! And it is said that a bit of voltage out-of-balance is not too serious. True?
Probably. What do you think?
But, the LiPo can run at 5C with no problems and 10C in short bursts. Generally
NiMh appear to run about 4C maximum for continuous running, and only then if
they are Hi-Drain type (how do you recognise these?)
(Editor: You can buy 5S2P Kokam 2000mAh 15C cells for around £137
(www.islandrc.co.uk), where 18 GP 3700 cells will cost £108 from Overlander.
The LiPo pack is more expensive but you get slightly more capacity and they are
rated as 15S (30A) continuous and 20C (40A) peak, or 60A/80A for 2P. You can
charge NiMH cells in under an hour, but it is best to charge them more slowly.
At 1C a LiPo should be charged in 1.5 hours so not a huge saving there. GP3700
cells are equivalent to NiCd cells up to around 40A (~10C), not much different to
LiPo. The difference is that GP3700s don’t mind you taking 200A in small doses.)
Any comments anyone cares to make (to Peter on 01276 21 304 or PGLV@aol.com)
would be appreciated but, based upon years of ignorance, it would appear to me
that NiMH is the way to go. Cheaper, more forgiving - but double the weight!
E.F.-U.K.
49
TLC from your TLO
by Alan Bedingham
I’ve got several things to talk about this time, one of them quite technical I’m
afraid, but then I am the TLO aren’t I?
Battery Storage
I talked about this last time, the difference is that now I can relate from personal
experience because I’ve done no flying at all from September last year till June
this year as a result of a combination of bad weather and poor health keeping me
away from the flying field. So how did my batteries stand up to this long period of
idleness?
The NiCd flight packs were fine. They were stored discharged in a warm room
and took nearly a full charge straight away. Half a dozen flights later and they’re
back to their usual capacity.
The NiCds in my transmitter were stored nearly fully charged and still showed a
reasonable voltage when I turned the transmitter on. I ran them through 3
discharge/charge cycles on my Schulze and they were down to half their rated
capacity. Not good. I should tell you that these are AA size Sanyo KR1100AAUs
that I’ve had for at least 3 years, probably the best NiCd in terms of capacity you
can get for their size and ideally suited to transmitters.
I didn’t want to just throw them away unless they were completely done for, (yeah,
I know, tight as a duck’s ….) so I tried a trickle charge of 100 mA for 14 hours to
try to get all the cells in the pack at the same state of charge. A discharge now
showed 0.9Ah, nearly back to normal. Running 3 discharge/charge cycles again
brought them consistently up to just above 1Ah, almost as good as new. Winner!
There’s three lessons here :1) Always discharge NiCd packs before long term storage.
2) Don’t give up on a pack that seems to have died, try trickle charging it to
level the cells out.
3) A charger that can discharge as well as charge is well worth buying. I
discharge my flight packs when I get home from flying as a matter of routine.
All my NiMH packs died, generally by losing most of their capacity. Nothing I
tried would revive them, even dumping very high currents into them from a
capacitor just in case crystals (called dendrites by the way, lovely word isn’t it?)
had grown between the plates. I’m no longer a member of the NiMH fan club.
The LiPo pack had been fully charged before storage. I put it on the charger and
it put 200mAh into the 1500mAh pack, that’s only a 13% loss of charge in 10
months! Amazing. Now I recharge the pack when I get back home from flying
50
E.F.-U.K.
knowing that it won’t need to be topped up even if I don’t fly for a week or two.
This is just the opposite to what I’m used to with NiCd cells, they seem to self
discharge quite quickly.
The lead-acid car battery I use for field charging seemed low on voltage even though
I’d religiously given it a top up charge every fortnight. It still had a few months of
the four year warranty left, so, nothing ventured, nothing gained, I took it back to
the supplier. He called out the Rep. who took it away for testing.
A couple of days later I got a ‘phone call, the manufacturer had found one cell down
and would I like to come in and collect the brand new replacement they’d left for
me. Another winner! Mind you, it’s a bit optimistic to expect a lead acid to last 4
years given the way we treat them, 2 years is good, anything more is a bonus.
This all bears out what I was saying last time about battery storage, the only new
information is that, based on a sample of one, it looks like storing LiPo fully
charged isn’t a problem.
Brushless Motors
Talking to people, I get the impression that there is some confusion about the
advantages and disadvantages of brushless motors in their various forms versus
brushed motors so I thought it might be a good idea to run through all the motor
types for you, starting with the typical ferrite ‘can’ motor like a Speed 400 or 600.
They’re called can motors because the casing is pressed out of steel the same way
that a tin can is. Ferrite because the magnets are made of sintered ferrite. This
is an iron based powder bashed together in a mould – sintered. This makes them
very cheap to manufacture, you can get a Speed 400 for around £4 which is less
than two pints of beer — at least around here it is!
They’re made in millions for use in cars and power tools and hairdryers and such.
The bad news is that the magnet material isn’t very powerful so they only get good
efficiencies if they run at high speed. The brushgear is a bit wimpy for the sort of
currents we like to use and wears rapidly. We tend to run them direct drive at
quite low speeds so the efficiency is usually in the 50-60% range.
The next step up is to use better, more powerful magnets, either Samarium Cobalt
or, more commonly nowadays, Neodymium, both called ‘rare earth’. The motors
available to us using these magnets are usually designed specifically for our use
with machined cases, ball raced shafts and big, chunky brush gear. They cost
more but you gain durability and, due to the stronger magnets, much better
efficiency at low revs, easily reaching 75-80%.
Up again to the standard brushless motors that turn the whole design inside out.
The magnets are now on the rotating shaft and the windings are stationary inside
the casing. The brushgear is replaced by complex electronics inside the speed
controller that does the switching of the coils to make the magnets on the shaft
rotate. Cooling is very good with this layout, allowing relatively small motors to
E.F.-U.K.
51
take high currents and produce high power compared even to a brushed rare earth
motor. The bad news is that they often need a gearbox to get enough torque to
swing a reasonable size propeller, somewhat reducing the weight advantage.
Efficiencies can go to 90%, reduced a bit by the gearbox losses.
A bunch of clever people in Germany decided that what they needed was a brushless
motor that didn’t need a gearbox and so the outrunner motor was born. What
they did was to leave the magnets on the shaft but put them outside the coils to get
more torque and use more of them to reduce the running speed, a sort of
electromagnetic gearbox. It turned out that cooling wasn’t a problem, so very
small and light motors could produce quite high power outputs. The bad news
was that efficiencies were not as good as a standard ‘inrunner’ brushless and
gearbox, in the 75-80% range, but this is offset by the low weight.
In short, if you want cheap, go for a ferrite can motor. For not a lot more and a
significant gain in efficiency and durability, get a brushed rare earth motor. For
the ultimate in efficiency get a geared brushless which will cost a lot more because
of the gearbox and the complex speed controller.
For really light weight and reasonable efficiency get an outrunner, a bit cheaper
than a standard brushless motor. The cost argument is relevant because I often
talk to people who want to dip their toes in the water and replace a Speed 400 with
a brushless. This is really not a sensible thing to do, you’re going to spend nearly
a hundred quid to get a little plane to fly a bit better for what is really quite a lot
of money. It’s far more sensible to spend the money buying a bigger brushless for
a bigger ‘plane since the cost difference between little brushless motors and big
ones isn’t that much. If you want to make your Speed 400 size ‘plane fly better,
get a brushed rare earth motor.
Glitch Busting
I know I’ve been through this before and you’re all probably yawning by now, but
I still get queries regularly on this subject, so it might be worth repeating for the
newcomers amongst us.
We electric fliers are worse off than the oily fan drivers simply because we’re
carrying around our own personal interference sources in the ‘plane and they
won’t go away. I’m talking about motors, speed controllers and battery wiring.
Suppression can help here on brushed motors - make sure you fit capacitors to the
terminals. In general, any capacitor is better than none, but I use a set of values
that apparently are optimum for suppression at 35MHz. They are 0.47 mF (marked
474, Maplin part no RA52G) across the terminals and .047 mF (marked 473,
Maplin part no RA47D) from the terminals to the can.
The 10:1 ratio is important as is the type of capacitor — they need to work well at
high frequencies for best results. Most good brushed rare earth motors will have
them fitted already, usually on a little PCB inside the case.
52
E.F.-U.K.
Speed controllers are less obvious. All speed controllers nowadays have some sort
of computer in them running at several MHz and that produces high frequency
(electrical) noise. Not only that, they’re busily chopping up the high motor current
into square waves that are notorious for producing high frequency noise.
This applies to brushed and brushless controllers with, if anything, the brushless
controllers being the worst, at least a brushed controller on full throttle doesn’t
have to do any chopping of the motor current. Brushless outrunners are particularly
bad, the controllers have to run at very high frequencies.
This noise can easily be in the same band as we’re using for the radio link, and to
cap it all, the wires going to the motor and the battery make pretty good antennas.
The further away you can get the receiver from the noise, the better. The best
possible layout is, from the front of the ’plane :Motor
Speed Controller
Flight Battery
Servos
Receiver and it’s battery
My battery packs always have very short (20-30mm) leads, not the usual 100150mm they’re generally supplied with. Two reasons – one, the less the tangle of
wiring , the less the electrical noise – two, if you’re using gold bullet connectors,
it’s possible, if you’re distracted, or a bit careless, to connect the two battery
connectors to each other.
The first hint will be the smell of burning fingers as the battery does it’s best to
turn it’s wires into electric fire elements, the second will be the cells themselves
exploding. What’s really nasty about this scenario is that by the time you’ve
realised what you’ve done, the wires are glowing red hot and there’s no way you
can pull them apart again! All you can do is watch as your beloved toy gets
destroyed. It sounds unlikely but, I can assure you, it has happened!
While I’m talking about connectors, those dreadful Tamiya connectors that battery
packs always seem to be supplied with can cause problems too. They seem to lose
conductivity in a surprisingly short time and get in a state where they look all
right but are only making intermittent contact. You can imagine the sort of
glitches this can cause if you’re using the speed controller’s BEC to power the
receiver!
What happens if you’ve done all these good things and you still get glitches?
Well, it happened to me!
The ‘plane is a Vermont Belle with an AXi 2820/10 outrunner and a Jeti speed
controller on eight cells drawing around 38A. Every now and then I would get an
E.F.-U.K.
53
almighty glitch, all controls slamming to the end stops for a fraction of a second,
more common was a slight twitch, not enough to worry about. Clearly this couldn’t
go on, that major glitch might happen when the ‘plane was in a position to cause
damage to property, or worse, people.
The equipment layout was good, the receiver was a high quality JR R700, where to
go next?
First suspect was the BEC output from the controller. I hooked up an oscilloscope
to the BEC output and got clean DC with not a trace of ripple at all motor speeds.
Hmm, must be airborne RF noise. Let’s try putting ferrite rings on the input and
output of the speed controller and wrapping it in aluminium foil to make a Faraday
cage. That didn’t work either.
I’d heard good reports of the Schulze Alpha receivers, so I bought one. They have
a signal processing circuit that replaces a dodgy pulse train with the last good one,
a bit like the way PCM receivers work. Put it in and set the antenna up as
recommended with half in the ‘plane and half hanging free underneath.
It seemed better, but I could feel an odd effect when I was flying. It’s hard to
describe, the nearest I can get is a sort of ratcheting feel to the controls as the
receiver replaced the signal I was sending with the one before.
Obviously the interference was still getting through and the Schulze was trying
it’s hardest to help me out, but I really didn’t like the feel of the aeroplane any
more. Then the penny dropped.
I’d had big problems with my Pondside flying boat that has a really dreadful
equipment layout and I’d solved that by fitting a vertical whip antenna using a
piece of plastic tube with the receiver antenna running up it. Fitted one to the
Vermont Belle and put the JR receiver back in and all I got was minor glitches and
the ‘plane now felt fine.
One of my oily fan friends (who used to be a BT engineer) noticed it and asked me
why I’d done it. I explained and he the told me that even the oily fan drivers got
random glitches in some parts of the field. Pardon?
It turns out that our field lies between two mobile ‘phone masts and when they
talked to each other certain parts of the field were hit by quite powerful signals
that swamped our signals even though they’re way off our frequencies.
The Vermont Belle suffered badly because it had a particularly noisy installation
due to the outrunner motor. All that grief caused by people saying ‘I’m on the
train’! Ah well, more lessons learned!
Cubic Wing Loading
I’ve heard of this before but not really dug into it much until an article in The
Ampeer Flier reminded me. It’s a way of estimating how well an aeroplane will fly
that is independent of size, unlike wing loading.
54
E.F.-U.K.
Wing loading is the weight of the aeroplane divided by the wing area and is generally
thought of in ounces per square foot – at least it is if you’re as grey haired as me!
The trouble is that the optimum wing loading varies with the size of the ‘plane,
varying with Reynolds number and scale effects.
The idea of cubic wing loading (CWL) is to give a number that is independent of
size and therefore can be a useful way to estimate if your next project is going to be
a lead sled or not.
The calculation is simple if you’ve got a scientific calculator – divide the weight of
the ‘plane in ounces by the wing area in square feet raised to the power of 1.5
(might be easier to cube it and then take the square root (Sqrt)). The answer is a
number that should be between 7 and 20 for the ‘plane to fly well, low numbers for
floaters, high numbers for something closer to a lead sled.
CWL =
Weight
(Wing Area)1.5
Some examples :A full size Cessna 154 has a CWL of 13 but a wing loading of 167 oz./sq.ft. A scale
model with a wing loading of 167 oz./sq.ft. would not fly very well!
My Vermont Belle is very light for it’s size so let’s see what we get. Wing area is
565 sq. in. – divide by 144 ad we get 3.92 sq.ft. Cube this and take the Sqrt and we
get 7.76, divide this by the weight of 50 oz. and we get a CWL of 6.44, a very low
number – very similar to my 2.5m Silent Dream glider. The wing loading of the
Vermont Belle is 12.7 oz./sq.ft., the Silent Dream is 14.2 oz./sq.ft., quite different
really, but the similarity of CWLs suggest that they should feel as light as each
other in the air, and they do.
My Bristol M1C came out heavier than I’d like, carrying out the same calculation
gives a CWL of 12.5, comfortable, but could be lighter. The wing loading is 26.6
oz./sq.ft. These are very different ‘planes which would be hard to compare using
any other criteria, I feel this concept has some merit, what do you think?
Don’t let the smoke out!
Editors comment
I have been using this system for quite a while, although calling it Wing Cube
Loading (WCL), and I think it works extremely well.
I even produced an online WCL calculator that is available on my personal website.
It is as simple as entering the wing area (sq.in.) and weight (oz.) and clicking the
calculate button. It then displays the metric wing area and weight, wing loading
and WCL. Try it at www.ef-uk.net/data/wcl.htm
There is an article written by Bob Boucher on Understanding Scale Speed, which
is interesting and explains how to get a scale model to flying like the full size.
E.F.-U.K.
55
It is available on the Astroflight website (www.astroflight.com) under Articles
on Electric Flight and then Understanding Scale Speed.
The ratios, relevant here, that Bob Boucher recommends are:
Model Weight = (Full Size Weight)
Scale3
Model Wing Loading = (Full Size Wing Loading)
Scale
The above doesn’t include the WCL and it is not referred to in the article. However,
if you’re fair at mathematics you’ll be able to demonstrate that the scale factors
(for weight and wing area) above result in the same WCL for full size and model.
As always there are a exceptions to any rule. The main exceptions are Fighter
aircraft and modern jets. To illustrate the full size Hawker Sea Fury has a wing
span of 38’ 5”, an area of 280 sq.ft., a max mass of 12500 lbs and 2480 hp. This
gives a WCL of 42.7 (ouch!). Using the above for a 1/10th scale we have 46” span,
wing area of 403.2 sq. in., a weight of 200 oz. (12.5 lbs.), giving a wing loading of
71.46 oz./sq.ft. and need 0.78 hp (585W).
If the model was built to the above it would give a model with a flying speed that
appears scale. The full size Sea Fury has a stall speed of 105 knots, clean, at
12500 lbs. This would be 33 knots for the 1/10 scale model and certainly a
challenging hand launch. With scale power the model’s take-off run would also be
scale - can you live with a take-off run that is 100m+ long?
Bob Boucher recommends that aircraft with very high WCL values are built to
around half the scale weight and power figures determined above. For my example
this gives a weight of 6¼ lb. and a power of ~300W. This would give a wing
loading of 35.7 oz./sq.ft and WCL of 21.3, which is much more sensible.
This is more what would expect for this size of model (although the weight could
still be reduced). I hand launch my Easy-Jet which has a WCL of 20.5, however,
in calm conditions it can be very marginal.
I’ve produced a couple of graphs with WCL values for full size and model aircraft
to show the range of figures that are common.
My recommendations are:
For scale models aim for the original models WCL value. Where the WCL is
excessive, reduce the weight and power required by half and an acceptable
WCL is should be achieved (perhaps reduce to 1/4 for a Sea Harrier).
For hand launching avoid a WCL much above 15.
For non-scale models, the guideline WCL figures that I work to are: Gliders
under 4, Powered Sailplanes & Trainers 6 to 7, Aerobatic 9 to 10, Scale-like 12
to 13 and Racers can be 15 and over.
56
E.F.-U.K.
E.F.-U.K.
57
58
E.F.-U.K.
E.F.-U.K.
59
Electric Flight Calendar
If you would like details of your event to appear in these pages please send full
details to the Editor EF-UK, contact details on page 4. Please bear in mind that
this magazine is quarterly so ensure that the details are sent in good time.
For last minute information on events please check out the events list on the
BEFA website (www.befa.org.uk). Dates, times and, even, locations of events
can change at the last minute. You are strongly advised to check on events with
the given contacts before setting out on your journey to any event.
All BEFA flying events require proof of BMFA (or equivalent) insurance
and an ‘A’ Certificate to fly. For fixed wing models, any of the fixed wing ‘A’
certificates are acceptable. For helicopters, a helicopter ‘A’ certificate is required.
All flying models must have been satisfactorily flown at least twice
since build or repairs before flying at a BEFA event. NO TEST
FLIGHTS ON THE DAY.
October 2005
2nd
Unlimited Scale Competition at the Pontefract and District
Aeromodellers flying site, Pontefract Racecourse, Pontefract Park
Junction 32 of the M62, Yorkshire. F4C flying schedule, low-key
static element. Contact Philip S Kent on 01274 873 069.
15th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre, Ninelands Lane, Leeds, LS25 - off the A63 LeedsSelby Road. Flying from 2pm to 5pm. Separate slots for Slowfly,
Aerobatic, Scale and Helicopters. Sub 350 and equivalent brushless
motors only. Any legal frequency. Proof of BMFA membership
essential. No free flight or IC. Spectators £1 on balcony Pilots £5.00
(Juniors £2.00). Contact John Thompson on telephone 01924 515
595, email him at johnty99@ntlworld.com or see the Northern Area
website http://members.aol.com/bmfanorth
November 2005
6th
60
BEFA Technical Workshop at the Royal Spa Centre, Royal Leamington
Spa, Warwickshire. The doors will open for traders to set-up their
stands at 8am, with the doors opening to the public at 9.30am. All
the usual features:
Technical Presentations. The talks are still being finalised, keep an
eye on the website (www.befa.org.uk) for more details. Any traders
wishing to attend that have not received an invitation should contact
the Secretary, Peter Turner (see page 4), for details and to reserve
your free tables.
E.F.-U.K.
Traders’ Fair. The list of traders is being prepared - see the website
for the latest list. Confirmed to date are All Electric RC, Elston Models,
ImporTekniK, Inwood Models, ModelPower.co.uk, Phoenix Models,
Puffin Models & RobotBirds.
Bring & Buy Stall. As usual the Bring & Buy stall will be set-up in
the Foyer. Items can be registered and left at the stand from 9.00am,
but trading starts only once the main doors open.
If selling items please complete a copy of the registration form overleaf.
Please do not complete a separate form for each item, although multiple
forms can be used if more space is needed. It is also essential that
items are labelled with a minimum of your name & the asking price.
Raffle. The committee will be asking traders for raffle prizes as
normal. The draw will take place prior to the last technical talk.
Tickets. The ticket prices for the Technical Workshop have remained
the same as for 2004:
£6 in advance*
£8 at the door
Mail orders for advance tickets must include an SAE for return of
the tickets. Please also include a contact telephone number in case of
queries. Requests should be mailed with a cheque, payable to B.E.F.A.,
to: TWS Tickets, 111 Plantagenet Chase, Yeovil, BA20 2PR
Alternatively advance tickets may be purchased from the BEFA website
at www.befa.org.uk/tws.htm using PayPal. Alternative online
payments methods are available, contact the Editor for details. (*When
purchasing online there will be an additional charge of 15p per ticket
and handling fee of 55p per order added to the cost of the tickets. This
is due to the fees payable to PayPal and to cover postage of tickets) .
Ticket orders received before 30 October 2005 will be posted. After
that date the tickets will be available for collection at the door as
otherwise they may not arrive on time. Any questions on ticketing
should be made to the Editor (see page 4).
19th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre. See October 15th for details.
December 2005
10th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre. See October 15th for details.
January 2006
15th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre. See October 15th for details.
E.F.-U.K.
61
62
E.F.-U.K.
February 2006
19th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre. See October 15th for details.
March 2006
19th
BMFA Northern Area Indoor RC Flying at the Garforth Squash &
Leisure Centre. See October 15th for details.
July 2006
2nd
Ebor Silent Flight meeting on the York Racecourse.
9th
Chester "Roodee" Electric Fly-In (date changed to avoid Ebor event)
FOR SALE / WANTED
Member's Sales & Wants
For Sale by Ken Paulson. For more information contact Ken on 01332 881 584.
• Futaba FF8 Transmitter with manual, carry case & neck strap all in very good condition, price £120.
• Graupner Speed 600 7.2V with Kruse Synchro-Gear belt drive 2.25:1,
Teutonic Perfection - £25
• Master Airscrew gearbox with 7.2v 600 motor, only £10
Neil Stainton is selling the following items. All are plus postage or can be picked
up from Leamington Spa. Contact Neil Stainton on 01926 314 011 or email him at
Neil@ITpartnership.com
• Schulze 6-636+ 8A charger for 1-36 NiCd / NiMH cells & 1-11 LiPo cells.
V8 software: £179
• New Blade Runner indoor helicopter, including 27Mhz R/C, LiPo
battery & charger: £49
•
•
•
•
Hornet Helicopter FP VGC, with carbon blades: £35
GWS PG03 gyro: £19
Blue Arrow 4.3g servos, new, boxed £8.95 each
Blue Bird 3.4g quality micro servos with coreless motor £11.95 each
Dennis Hey is selling CD-ROM motors £ 2.00 each, or 2 for £3.00, postage
included. Contact him at dennis@hey13.freeserve.co.uk or 01943 862 761.
E.F.-U.K.
63
Wanted: A Mini Laser 3D kit preferably not started, but a built model in good
condition also considered. Contact Gareth Hodges on 01873 830 808 or email him
at Gareth.Hodges@btopenworld.com
Neil Stainton wants a Highlight Electric Fuselage, any condition. Contact Neil
at Neil@ITpartnership.com or on 01926 314 011
Gareth Hodges wants a Hacker B20-15L and 4:1 Gearbox, must be in good
condition. Call Martin on 01873 830 808 or at Gareth.Hodges@btopenworld.com
For Sale by Martin Collins. Call 01908 583 545 or
email kartman.nascar24@btinternet.com. Can
be collected from Milton Keynes
• KYOSHO T-33 in Thunderbirds aerobatic
colours. Comes with the motor & fan unit
installed (I was told it was a WeMoTec fan but
I cannot confirm it). Good condition apart from
a couple of missing decals. Price £60 (no offers).
• RIPMAX ARTF SPITFIRE fitted with AXi 28/
20/10 and model motors brushless controller.
The Spitfire has 2 mini servos in it (aileron/
elevator) and comes with an 8 cell 2400 Sanyo
pack and 11" x 7" propeller. Just fit your
receiver to make it a flyer, selling due to house
move and other projects it has only 6 flights
from new on it, price is £200
The items below are for sale by Trevor Wain, contact at trevorwain@tiscali.co.uk
or on 01332 792 508.
• Puffin Models Elegant, 2.6m glider / electric glider. Flown twice, but
other interests took over - no equipment fitted. Offers around £100.
• Kontronik Smile 40-6-18 opto, brushless, speed controller, 40A 624V with Kontronik 4mm silver connectors on the output and Schulze 3.5mm
connectors on the input and has been used twice. He would like to exchange
for the same or very similar with BEC or sell for £65.
Jim Horne has a WeMoTec Midi-fan with Aveox 36/24/2 sensorless brushless
motor for sale - £70. Email Jim at HORNEGb@aol.com or phone 01388 819 638
Peter Vivian would like to contact any others in his approximate area (Camberley,
Surrey) who are also new to Electric Flying, with a view to mutual assistance and
support. Peter returned to model aircraft fairly recently after a 55-year break,
with an interest mainly in building and experimenting (definitely NOT ARTF!).
He would like to meet up with others having similar interests. Contact Peter by
email at PGLV@aol.com or on 01276 21 304
64
E.F.-U.K.
New to ELECTRIC FLIGHT?
START HERE . . . . .
You may be taking up Electric Flight for the first time or you may be converting
from another discipline. Whatever your situation, help and advice is available.
BEFA has prepared an information sheet which details further sources of
information which you may find useful when just joining the hobby. To receive a
copy, please send a Stamped Addressed Envelope (S.A.E.) to Robert Mahoney,
address on page 4.
BEGINNER'S GUIDE
A Beginner’s Guide to Electric Flight is available, which explains many of the
‘Mysteries' of Electrics’ and will, hopefully, set you off on the right foot. Please
send £3.00 per copy required to The Editor of EF-UK at the address on page 4.
Please add £1.00 extra for overseas postage and remit in Sterling. Cheques should
be made payable to BEFA.
TECHNICAL HELP SERVICE
Technical help is now available again for the use of all members. We regret that
no telephone service is available, but all questions in writing (or email) will be
answered by our Technical Liaison Officer (TLO). Please refer your queries to our
TLO, to the postal or email address on page 4. If sent by post, please ensure that
you include an S.A.E. for a reply.
CONNECTIONS SERVICE
Requests are frequently received from members who wish to be put in contact
with other members living in the same area. The easiest method of doing this is
to place a free 'wanted' advert in the classified section of this magazine.
Alternatively, a request may be made IN WRITING to the Membership Secretary
who is allowed to divulge such information to members ONLY. Please supply as
much information about your location as possible and please remember to include
an S.A.E. for your reply.
B.E.F.A. MEMBERSHIP
Membership of the Association is open to all. Those who are not members of
BMFA (our national controlling body) will have a subscription to EF-UK membership
with none of the other benefits. Overseas members are very welcome and will be
classed as full members if they belong to their own national controlling body.
CONTACT
For full details, please send an S.A.E. to the Membership Secretary (address on
page 4) requesting a membership application form. Those with Internet access
may visit the B.E.F.A. website at www.befa.org.uk where you will find all the
membership information you should require and a application form.
E.F.-U.K.
65
B.E.F.A. Sales
BEFA Round, Coloured Rub-down Decals - Ultra-thin & light - 50p each
EF-UK Back Issues - Issues 71 to 73 and 75 to 81 are available to BEFA members
at £3.00 each, or £5.00 each to non-members. These prices include UK P&P,
overseas rates on application. Reprints of earlier issues may be available to special
order at slightly higher cost, contact the Editor for details (see page 4).
EF-UK Index. A comprehensive index of EF-UK, from issue 28 to date, is available
by sending a £1 coin to cover copying and postage cost.
Binders:- are available to hold 8 to 12 issues of Electric Flight U.K. Produced in
dark blue with gold lettering on the spine, these cost £4.50 each including U.K.
postage. Please add £1 for European postage and £2 for Worldwide postage.
Please send all orders to The Editor of EF-UK at the address on page 4.
Sweat Shirts & Tee-Shirts: Stock of these is now almost all gone - please
contact Robert Mahoney regarding remaining stock, sizes and prices.
PLEASE REMIT IN STERLING ONLY,
WITH ALL CHEQUES MADE PAYABLE TO B.E.F.A.
Advertisers Index
BEFA Sales ................................................................. 66
Fanfare.............................................. Inside Back Cover
For Sale / Wanted ....................................................... 63
ImporTekniK ..................................................... 58 to 89
New-2-U ............................................................... 9 to 18
RC Groups / E-Zone ......................... Inside Front Cover
Traplet ............................................Outside Back Cover
EF-UK advertising rates are £25 per inside or outside cover page,
£20 per full page, £10 per half page, all per issue.
Contact the EF-UK Editor for more details (see page 4).
66
E.F.-U.K.
– MAIL ORDER –
SPORTS ELECTRIC FLIGHT
FANS AND GEARBOXES
www.fanfare.f9.co.uk
GEARBOXES
FANS
Morley ‘Jet Elec’ Fan .............................. £15.00
WeMoTec Micro-Fan (280/300/330) ..... £14.00
WeMoTec Mini-Fan (400/480) ............... £28.00
WeMoTec Midi-Fan (540/ 600/930) ....... £38.00
MOTORS
MPJet Brushless motors; 9 motors; outrunners,
inrunners & geared; 280 to 700 .... £37.00 to £58.00
WEP Turbo 10 ....................................... £55.00
Fanfare Silver 16T & 20T ...................... £34.00
Fanfare Powermax 40T ........................ £38.00
Speed 600 8.4v BB SP .......................... £17.00
Speed 600 8.4v Race ............................ £22.00
RE 380 / Rocket 400 ................................ £5.00
Speed 480 BB ........................................ £21.00
Pro 400 .................................................... £5.00
Pro 480 HS ............................................... £6.00
Pro 480 HS BB ......................................... £8.00
MAXCIM BRUSHLESS
Max Neo 13Y 1430 rpm/v ................... £160.00
Max Neo 13D 2470 rpm/v .................... £160.00
Maxu 35D, 21 Cell Controller ............... £140.00
Maxu 35C, 25 Cell Controller ............... £180.00
Superbox 1.6 to 4.28:1 ......................... £50.00
Monsterbox 4 to 6.8:1 .......................... £60.00
Motor Mount ........................................... £12.00
Master Airscrew - 2.5, 3, 3.5:1 ............................. £18.00
MP Jet Planetary - 3.33 & 3.8:1 - 400 / Pro 480 ...... £28.00
MP Jet Planetary - 3.33 & 3.8:1 - Speed 480 ........ £28.00
MP Jet Planetary - 3.33 & 3.8:1 - 540 / 600 ............ £28.00
MP Jet Plastic BB - 4 & 5:1 - 280 / 300 ...................... £8.00
MP Jet Plastic BB - 3, 3.5 & 4:1 - 400 / Pro 480 ......... £8.00
MP Jet Plastic BB - 2.33, 3.5 & 4:1 - Speed 480 ..... £10.00
MP Jet Plastic BB - 1.75, 2.33 & 2.8:1 - 540 / 600 .. £15.00
Mini Olympus ............................................ £8.00
Olympus ................................................. £12.00
MOTORS / GEARBOXES
Speed 400 FG3 ..................................... £17.00
SpeedGear 400 4:1 Inline ...................... £38.00
SpeedGear 480 3.45:1 .......................... £55.00
SpeedGear 600 2.8:1 ............................ £52.00
SpeedGear 700 2.7:1 9.6v .................... £70.00
SpeedGear 700 Neo .............................. £92.00
Mini-Olympus & RE380 .......................... £12.00
Olympus & 540 ...................................... £19.00
Jamara 600 2.9:1 ................................... £24.00
Jamara 650 2.9:1 ................................... £26.00
PROPS
M.A. Folding
M.A. Wood Electric
CHARGERS
Speed 1 Pulse / Pk
Det 4-8 cells ........................................... £27.00
Speed Ex Digital
as above with discharge ...................... £55.00
Simprop 25 cell .................................... £100.00
Wheels, Wire, Servos, Fuses, Caps,
Powerpole, 4mm & 2mm gold conns.
Carbon Folders
(Perkins)
Slimprops
APC Electric
(full range available)
12x8 ................ £14.00
15x12 .............. £15.25
10x6/10x8 ......... £4.00
11x7/11x9 ......... £4.25
12x8/12x10 ....... £4.50
13x8/13x10 ....... £5.00
7x4 .................... £6.00
8x4 .................... £6.00
11x8 .................. £9.00
8x4, 8x6, 9x6 .... £3.50
5½” - 12” dia . £3 to £4
13 ” - 20” dia.£5 to £15
Selection of Graupner & Aeronaut
folding & fixed props.
FANFARE • 18 HILLSIDE ROAD • TANKERTON • WHITSTABLE • KENT • CT5 3EX
‘Sports Electric’ Helpline - Phone / Fax: (01227) 771331 - E-mail: john.swain1@virgin.net
Now online at - www.fanfare.f9.co.uk