The Boomerang - EAA Chapter 40

BOOMERANG
Burt Rutan Uses Airframe Asymmetry To Achieve
Aerodynamic Symmetry In His New Personal Airplane
BY JACK COX
f
O
n Thursday, August 1, 1996
the aviation world got its first
look at Burt Rutan's new
Boomerang when it came b l a z i n g
down runway 18/36 at Oshkosh, right
in the middle of the afternoon air show
and right on cue from his brother, Dick,
who was providing a running commen-
tary on the PA system. In the quarter of
a century since his first appearance at
Oshkosh in his VariViggen we've
come to expect the unusual from Burt,
but when he rolled his latest creation
up on its side to show off its planform,
we knew he had stepped up to an entirely new level of aeronautical exotica.
Symmetry has always been a hallmark
of aircraft design, but here flashing before us was an airframe that except for
its two vertical fins, appeared to be totally asymmetrical. How could this be?
There were two fuselages, one larger
around and longer than the other . . .
each had an engine on the nose, but the
left one was back several feet behind
the one on the r i g h t . . . the horizontal
tail was longer on the right side than
the l e f t . . . and, strangest of all, the
wing was shaped like a boomerang. A
forward facing boomerang. How could
anything shaped like that fly straight
and be controlled?
Obviously it could be, because Burt,
his wife, Tonya, and son, Jeff, had just
flown 1,505 nautical miles non-stop
from Mojave, California in six and a
half hours - and here was Burt making
a tight, smooth turn around the north
end of the airport and preparing to
make a second pass in review before
the huge Convention crowd. The perfectly normal landing that followed
further confirmed the controllability of
the airplane, but as it taxied onto the
West Ramp parking area and more
structural details came within view,
even more elements of asymmetry became obvious. The landing gear . . .
well, it was just all out of whack! The
nose gear was offset to the left of the
centerline of the fuselage — the right
fuselage, the one with the windows —
and the mains, amazingly enough,
were not in any common plane. The
right one was mounted further back
than the left one, and it retracted forward. The left main, out on the smaller
fuselage or boom, retracted backward.
How could the airplane roll straight
and how could it lift off on its staggered main gears without suddenly
veering off to one side or, at least, dipping a wing when one main came off
before the other?
Even the dam cabin doors turned out
to be different. After the Boomerang
came to a halt and the engines were shut
down, the big, almost round right windshield popped inward, then slid
backward out of sight — and up stood
g Burt to acknowledge the cheers and
E greetings of the crowd. As the winds' shield had retracted, a built-in step had
2 popped out of the side of the fuselage
SPORT AVIATION 19
and Burt used it to deftly climb out of
the airplane. Quickly ducking under
the right wing, he strode back to open
an airstair door that swung down to allow Tonya and Jeff to emerge from the
rear cabin. After a round of greetings
that included EAA President Tom
Poberezny and FAA Administrator
David Hinson, we had the opportunity
to peer into the 53 inch wide cabin . . .
and see even further examples of asymmetry. To the right of the airstair door
opening, and on the right side of the
cabin, was an aft-facing seat. Straight
ahead, on the left side of the cabin, was
a forward-facing seat; and to the left toward the rear of the fuselage was a
third seat. It faced forward and con-
tained a man-sized stuffed bear Burt
had brought back from a trip to Russia
a few years ago. Shortly before the
Boomerang's departure from Mojave,
one of Burl's employees had sneaked
inside and stuck a plastic overlay on the
right rear cabin window that from the
outside looked like one of Hollywood's
conceptions of an "alien" gazing out at
the strange sights of planet Earth. To
the culprit who committed the deed:
Right on! It looked perfectly appropriate in the Boomerang.
Up front in what can be termed the
cockpit, since it is effectively separated
from the aft cabin by the wing's spar
carrythrough, the right main gear wheel
well and a large instrumentation console, were two seats slightly staggered
so that the occupant's shoulders would
not rub together. Departing from the
usual practice, the pilot's seat was on
the right. Just below each windshield
were smaller round windows that allowed nearly vertical views downward.
The most arresting sight in the cockpit,
however, was the instrument panel —
or, more precisely, the lack of same. A
few digital readout gadgets, a Garmin
GPS/COM, transponder, circuit breakers and switches were clustered around
the top of the panel. . . there was not a
steam gage in sight. . . but, otherwise,
there was just a bare expanse of gray
nothingness. Only a large door on the
left side hinted at the possibility that
something might lurk inside that would
bear at least a semblance to a conventional instrument panel.
BACK TO THE BEGINNING
Actually, this was not my first exposure to the Boomerang. I had been
20 OCTOBER 1996
allowed a look at it a couple of years
ago while it was still in the early stages
of construction, with all the airframe
components built, assembled and sitting on the gear, but with all the
systems yet to be installed and the finishing of the outside surfaces still to be
done. At that time, Burt was really excited about the new construction
method he had employed to build the
fuselage and boom. As one of the pioneers in the use of composite materials
to build primary structure in aircraft,
It has been such a hard nut to crack
that he and fellow composite guru,
Brandt Goldsworthy, have been periodically sequestering themselves on
remote beaches to brainstorm potential
new techniques. About four years ago
they finally came up with what they
thought was a workable scheme, and
the Boomerang became the test bed for
it. Burt had been wanting to build himself a faster, longer ranged, pressurized
personal airplane to replace his Defiant
prototype, so the project became a way
Burt was also one of the first to realize to kill two birds with one stone.
The new construction method is still
the limitations of the methods and materials then in use. While well-suited to in the patent process, so Burt is not dihomebuilding where one's time and la- vulging any trade secrets at this time.
bor are chalked up to education and He did reveal in his forums at Oshkosh
recreation, composites have been '96 that it involved filament winding
frightfully labor-intensive (and thus and that some unique means of vacexpensive) in a production situation. uum bagging were employed, but
For years Burt has sought a new way beyond that he was waiting for the
to build with composite materials, with lawyers to do their thing. The process
the ultimate goal of a machine-run has subsequently been improved upon
layup and a single cure of everything, and is currently in its third iteration on
including all hard points and cutouts the Vantage, a single engine corporate
for windows, doors, access holes, etc. jet that Scaled Composites has de-
signed and is building for a customer.
At the time of my initial look at the
Boomerang in 1994, Hurt and his crew
of volunteers (the airplane was built after hours and on weekends in a corner
of Scaled Composites' main facility at
Mojave) were still marveling that they
had been able to build the fuselage in
just one all-night work session, and the
boom in just seven and a half hours!
The Boomerang's unusual configuration and the reasons for it were the
major topic of conversation during that
early visit. Just how he figured he
could make something so configurationally crooked fly straight was the
puzzle and he was getting a great kick
out of everyone's attempts to figure it
out. I certainly couldn't.
As I later came to understand the
reasons for the Boomerang's odd
shape, they sprang from Burl's desire
to retain the safe engine-out handling
characteristics of his centerline thrust
Defiant, without having to cope with
its problem of identifying a dead engine, as well as the noise and reduced
efficiency of its pusher prop. A conventional twin layout with its often
deadly asymmetrical thrust problems
after losing an engine was not even
considered. It could have been an option if counter-rotating engines and
props, such as were used in the Beech
Duchess and the last models of the
Twin Comanche, were readily available (and cheap) today, but that is not
the case. The problem, then, that Burt
had to address in the design of the
Boomerang was to somehow figure out
a way to use two tractor engines, so as
to avoid any performance degradation,
and still be able to counter the combined P-factor of two props turning in
the same direction at full throttle at
minimum airspeed . . . or, much worse,
one engine dead and the other at full
throttle at minimum airspeed . . . and
still come up with an airplane as safe
as the Defiant.
At Oshkosh this summer, Burt used
a chalk board to illustrate the thought
process he went through to come up
with the configuration of the
Boomerang, and it was probably the
best non-technical explanation he has
thought up to date. He began by drawing the planform of a conventional
light twin with engines mounted out on
the wings and briefly discussed why
such aircraft are actually asymmetrical
with both engines running. That, he explained, was because as the angle of
attack increases, the P-effect moves
both of the engine's thrust lines to the
right. Then he began to suggest solutions, which involved moving the
engines around to minimize the P-effect, and literally through a process of
elimination of bad effects, ended up
with the Boomerang configuration. He
conceded that there probably were
other configurations that might work
equally well if P-factor were the only
consideration, but thought that when
other requirements such as a baggage
area capable of handling luggage for
five and items as long as skis, fuel capacity for transoceanic range and high
performance on relatively low horsepower, he couldn't come up with
SPORT AVIATION 21
about where the wing needed to go
through the boom, so-o-o-o, that's why
the wing ended up in the shape of a
boomerang. To get the center of lift
where it needed to be relative to the
CG, the left outboard w i n g had to
sweep forward; and the right wing,
which had to lift the much heavier
This spartan panel in a high performance
twin makes sense only when one leams
that the "glove compartment" at the left
folds down to serve as a table for a
Macintosh Power Book laptop computer
that is actually the instrument panel.
anything better than the Boomerang.
In essence, what Burt designed into
the airframe was something akin to the
offset thrust line most of us are familiar with in single engine airplanes,
although much more complex. In
homebuilts like the T-18, the engine
thrust line is canted off to one side and
down to counter P-factor . . . or, in
simpler terms, the engine is put on
crooked so it will make the airplane fly
straight. Burt did the same thing in the
Boomerang, but he manipulated the
entire airframe to create a straight flying airplane.
The resulting configuration is something else! Burt wanted the thrust lines
of the two engines as close together
as possible, so he arranged the
Boomerang's body parts in such a
manner that the longitudinal dynamic
centerline and the entire CG box,
which is seven inches wide and four-
teen inches long, are outside the
airplane! The longitudinal center line
is just a few inches off the left side of
the fuselage (the one with the windows), and the CG box is just outside
the first window behind the left windshield. It is the placement of the
engines (actually the props) relative to
these reference points that takes care of
the P-factor problem — in conjunction
with other things like the twist in the
section of wing that lies between the
fuselage and boom that negates the ef22 OCTOBER 1996
The Boomerang's split rudder/brake
pedals. Each half actuates a separate
brake on the main gear wheels.
View forward from the airstair door. The
console at the left contains the computer that talks to the Macintosh Power
Book instrument panel. With its time
flown off just prior to Oshkosh '96, the
Boomerang was still very much in the
developmental stage when this photo
was taken. No time had been available
to upholster the cabin — which just
gave everyone at Oshkosh a better
look at how the airframe was built.
fects of the upwash from the right prop
and the downwash from the left one.
As can be seen in the accompanying
planview, the left engine is further
away from the dynamic centerline than
the right, which is just another factor in
taming the P-factor of two counterclockwise turning propellers (as well
as cutting down on noise). The props fuselage, had to sweep forward from
want to twist the airplane one way at the centerline of the boom. Really
minimum speed and Burt has positioned aerodynamic forces to keep
them from doing so.
A resulting challenge of this engine
disconcerting, at least visually, is the
ter of balancing the airplane, a task
made more difficult by the fact that the
carbon fiber structure was so light. The
To provide the necessary down force
to counter the pitching moment of such
an unusual wing, the horizontal tail had
to be positioned wa-a-y to the rear.
Such a long fuselage and boom, however, would result in a lot of wetted
area, so it was desirable to provide each
with a low drag pressure recovery (dolphin-like) shape. That, in turn, made the
aft ends of both the fuselage and boom
too small in cross section to support a
single, sufficiently large vertical tail, so
smaller twin vertical tails were used instead . . . which was serendipity at its
(or prop) placement was the little mat-
engines could have been placed sideby-side and still handled the P-factor,
but then the airplane would have been
much too nose heavy with just the pilot
and front seat passenger aboard. To
also allow carriage of three souls in the
cabin, baggage in the aft part of the
boom and over a thousand pounds of
fuel, the left engine had to be moved
back a considerable distance. Unfortunately, however, that placed it just
fact that the center of dihedral is the
centerline of the fuselage! This is
why the wing looks so different from
various angles.
finest because having a vertical tail in
each propeller's wash made the low
speed/high power handling just that
much better. The horizontal tail had to
be extended out to the right (and not to
the left of the boom) to compensate for
the large amount of overhang of the
right engine ahead of the wing.
,
rums, because he was willing to cast
aside convention and pursue what initially appeared to be purely nonsensical
paths to solutions. This sort of unconventional, original thinking is, of course,
what has made Burt one of the truly
great aircraft designers of all time.
nitions — no mags — and both have
close fitting Formula One-like shrouds
over the cylinders to make the best use
of every molecule of cooling air that
comes in through the inlets. To avoid
NUTS AND BOLTS
an engine start and you will see the in-
A couple of days after his arrival,
Burt gave me a tour in and around the
Boomerang to point out all the nuts and
bolts items. The two pointed ends of the
airplane contain turbocharged, fuel injected 360 cubic inch Lycomings, but
they are not alike in the placement of
their accessories. The engine in the nose
of the 30.6 ft. fuselage is a 210 h.p.
TIO-360-C1A6B he robbed from the
Catbird, which is now hanging from the
ceiling of one of the buildings at Mojave. The engine on the nose of the
boom is a 200 h.p. TIO-360-A1B built
24 years ago for a SIAI Marchetti S.210.
What clever engineering nuances
caused Burt to use two different dash
number Lycomings? None at all, actually. He used 'em because ". . . that's
what I had or could get cheap."
This nose-to-tail domino effect in the
design and placement of the various airframe components was roughly the
sequence Burt had to follow in creating
the Boomerang configuration. It was
only possible, he said in one of his fo-
The Boomerang was designed to
use two of Michael Zoche's 300 hp
diesel engines, so Burt wasn't too particular about what he hopes will be
temporary substitutes. Both engines
are fitted with Jeff Rose electronic ig-
the cracking and chafing so common to
air cooled engine baffling, the inlets
are actually part of the shrouds. Watch
lets moving as the Lycoming shudders
to life. At Oshkosh '96, both Lycomings were fitted with new 3-blade
Hartzell constant speed, feathering
propellers.
Back behind the engines, the airframe, as previously noted, is all
carbon fiber. All, that is, except the
vertical fins and wing tips, which contain antennas so are made of fiberglass.
Fuel is carried in three 57 gallon tanks;
one in each outer wing panel and an-
other in the portion of the wing that
extends between the fuselage and
boom — and up over the top of the
boom. Actually, the "tanks" are just
sealed portions of the wing. The outer
panels are almost completely wet. The
center section is considered the aux
tank and fuel pumps mounted behind
the engine in the boom transfer fuel
between the tanks as needed.
The Boomerang's electrically actuated retractable landing gear was
designed and built in-house rather than
adapting some existing lightplane gear.
The dual wheel mains and the single
SPORT AVIATION 23
Climb Comparison
10,000 ft Altitude
Lancair 4P
Boomerang
Baron 58P
-1500
-1000
-500
0
500
10001500
Rate of climb after Engine Failure
nose wheel are fitted with 5:00 x 5
tires and a spare is carried in the baggage compartment in the boom. Each
wheel of both the mains has its own
Cleveland disc brake, and each one
of these four brakes is plumbed to
separate segments of the pilot's rudder/brake pedals. These pedals are split
in half vertically and each half operates
independently of the other. The left
half of the right rudder/brake pedal actuates the brake on the left wheel of the
right main, and the right half of the
pedal actuates the brake on the right
wheel of the right main. Similarly, the
two left pedal halves actuate the brakes
of the left main. The reason for such an
unusual system is redundancy. There is
2000
2500
3000
Max Rate of Climb
no nose gear steering; ground steering
is by differential braking, so Burt
wanted the redundancy of two completely independent braking systems
on each main gear. While the system is
mechanically complex, the pilot never
pays it any mind. He simply stomps on
each set of pedals as he would in any
airplane. One can feel a spongy left or
right main wheel brake, however, Burt
says, because one half of the pedal will
feel firmer than the other. While the
system has worked well so far, Burt
says he would not use it again. He
wishes he had installed nose gear steering and may, in fact, retrofit the
necessary mechanism in the future.
Interestingly, one of the reasons for
Efficiency & Speed Comparison
Cruise at Best Altitudes
120
140
180
160
200
220
240
260
Cruise Speed ~ KTAS
-•-Baron 58P 650 BMP
-•- Boomerang 410 BMP
-A- Defiant 360 BMP
-«-Malibu310BHP
24 OCTOBER 1996
-O Cessna 421 750 BMP
-O- Duchess 360 BMP
-£-King Air C90 1100 BHP
280
mounting the right main gear further
back than the left was to keep the airplane from tipping back onto its tail
when passengers enter the cabin before
the pilot and front seat passenger climb
aboard. The right main is also closer to
the CG than the left one, so it has a different orifice for the air oleo strut,
more strut pressure and more air pressure in the tires than the left main.
The Boomerang's control system is
also unique, with the ailerons somewhat difficult to characterize. They
function normally as ailerons, but also
move down eight degrees to serve a
flap function, and up three degrees past
zero to increase cruise by about eight
knots. Flaperons is probably the correct term, but Burt thinks of them as a
means of centering the drag bucket all
across the speed range of the airplane.
The linkage is certainly different. The
right aileron is connected by push rods
to the right side-controller stick in the
cockpit, and the left aileron is connected to the left stick. A push rod
connects the two sticks to make the
system conventional in its operation,
but a servo motor is mounted on that
connecting push rod that can make it
longer or shorter. When the flaps are
lowered, both sticks move inboard and
when they are raised, the sticks move
outboard, but not with enough force to
detrim the airplane or induce roll.
The 36.25 ft wing has a laminar
flow airfoil that was originally designed by John Roncz for the Catbird.
John was involved in some other project at the time Burt was designing the
Boomerang, so Burt tweaked the airfoil himself to make the reflex work
properly and to get more fuel volume.
It's a 16% section. Wing area is 101.9
sq. ft and the wing loading is 41 pounds
per square foot. The aspect ratio is
13.5 to 1.
As alluded to several times already,
the Boomerang's baggage compartment is in the portion of the boom aft
of the wing. A large oval-shaped door,
currently attached with quick-release
fasteners, allows full sized suitcases to
be stowed, along with skis and other
long items. The rear of the compartment has space for a tool kit and the
aforementioned spare tire.
COMPUTER GAMES
There are three areas of intense
technical interest in the Boomerang:
JIM KOEPNICK
the airframe configuration, the new
type of composite construction, and
the instrument panel. Remember the
previously noted "glove compartment"
door on the left side of the panel? It actually opens out to create a table for a
Macintosh Power Book (laptop) computer which serves as the "instrument
panel." Burl's son, Jeff Rutan, is a
computer software engineer for
Hughes Aircraft and with his friend,
Art Ortez, a computer hardware engineer for Hughes, has developed a
system that monitors every function of
the Boomerang, including a lot of information pilots have never had access
to before — things like angle of attack,
which is calculated by measuring
speed, weight and the strain on the
wing spar, and percent of power, which
is calculated from manifold pressure,
rpm, altitude and temperature. Sensors
were mounted all over the airplane and
wired back to a computer in the mid
fuselage. That computer, through a
normal Macintosh serial port, talks to
the Power Book, so when Burt climbs
in to fly the airplane, he simply pulls
down the door/table, plugs in his Mac
and runs a program that displays the
desired parameters and helps with
flight management. He would have al-
properly closed.
Once in flight and in the cruise
mode, the Mac monitors all engine and
system functions, including angle of
attack, lift coefficient and control surface position, as well as performance
data such as indicated and true airspeed, pressure altitude, etc. The really
unique thing about the program is that
it automatically records the history of
the flight, which can later be studied at
home. Even while in flight, it can be
ready entered the particulars of his
flight at home, so the Mac already
knows how much fuel, baggage and
people are aboard, where the flight is
going, etc. The in-cockpit preflight begins with a glance at an icon on the
screen that consists of a planform diagram of the Boomerang, with little
boxes that glow red or green to show
the status of such things as fuel quantity, whether the landing gear is down
and locked and whether the doors are
Range & Speed Comparison
3^ ^ou1
^ 9ftn
o
Q.
W
s
-•- Baron 58P 6 seats 870 Ib fuel
-•- Baron 58P 4 seats 1140lbfuel
-A- Eloomerang 5 seats 1 008 Ib fuel
-10 - -•- L.ancair 4P 4 seats 561 Ib fuel
Q) *-t*U
<n
\
\
>
N
*\
^
\^ X ^
O2200)
O)
& 9nno ^uu
3
180200
\
400
600
800
1000 1200 1400 1600 1800
2000
Range With IFR Reserves ~ Nautical Miles
Note: The three data points are for 75%,
65% and 50% Power
SPORT AVIATION 25
instructed to recall on the screen the
last minute, the last 10 minutes or the
last 20 minutes of data so that, for ex-
ample, you can tell if a reduced oil
pressure has been a gradual process or
has just suddenly dropped. Another
nice feature is the ability to "compress" the bar graph-like data into a
single vertical row of symbols, so that
you can tell at a glance if any function
has changed. If the symbol moves out
of line, you instantly notice it.
The computer program, while
presently working fine, is still a work
in progress and probably always will
be. Jeff is constantly thinking up ways
to improve the presentation of data,
and Burt is always coming up with
new uses for it. He expects to ultimately have the computer set the flaps,
for example, and will have it control
the pressurization when that system is
installed.
Burt's pressurization, system, incidentally, will be different than
anything normally seen in aircraft. It
will be very simple, inexpensive and
require little attention from the pilot.
TRIALS AND
TRIBULATIONS
BOOMERANG MODEL 202
(Source: Burt Rutan)
Engines - Lycoming TIO-360A1B (200 H.P.) On Boom
Lycoming TIO-360C1A6D (210 H.P.) On Fuselage
Five-Place Seating/1 Bed - Boom Baggage
Cabin Pressurized To 7,000 Ft. At 22,000 Ft. Altitude
Weight Empty - 2,370 Lbs.
Maximum Fuel -1,007 Lbs.
Maximum Cabin Payload -1,000 Lbs.
Payload At Maximum Fuel - 865 Lbs.
Maximum Gross Weight - 4,242 Lbs.
•,••-:
j
Span-36.7 Ft. • Length - 30.6 Ft. • Wing Area - 101.7 Sq. Ft.
Aspect Ratio -13.2
Electric Retract Gear • Full-Span Aileron Reflex
Vmax - 283 Knots True (326 MPH) @ 18,000 Ft.
Max. Cruise @ 22,000 Ft. (75% Power) - 264 Knots (304 MPH) @ 1,500 Nautical
Miles Range
Economy Cruise @ 24,000 Ft. (50% Power) - 210 Knots (242 MPH) @ 2,100
Nautical Miles Range
Range Includes Takeoff, Climb And 45 Minute Reserve
Max. Climb - 1,900 FPM (2,900 FPM @ 2,800 Lbs.)
Stall Speed - 88 Knots At 4,200 Lbs. or 73 Knots ® 2,800 Lbs.
26 OCTOBER 1996
Not too long after my first look at
the Boomerang at Mojave in June of
1994, the project went on hold due to
the press of business at Scaled Composites. It sat in its walled-off corner
collecting dust until the Memorial Day
weekend of this year. At that point, according to Burt, he suddenly realized
that he would have three new airplanes
he has designed at Oshkosh '97 — and
four if he managed to complete the
Boomerang by then. The three other
designs are customer's airplanes, and
he really didn't want the Boomerang
competing against them for attention,
so he made the decision on the spot to
dust off the oF Boom, try to enlist as
much volunteer help as he could get
and start a crash program to get it completed and ready to fly to Oshkosh '96.
Unfortunately, "crash" turned out to
be a bad choice of terms.
With lots of help from his friends,
Burt had the Boomerang ready to fly in
mid-June, and he and Mike Melvill
made the first runway hops on June 17.
"One of the biggest problems I had
with this project," Burt recalled at
Oshkosh this summer, "was convincing people that it was a serious project.
Everyone seemed to think it was some
kind of bizarre experiment rather than
a serious attempt to build a better, safer
twin. Despite the doubters, I had every
confidence in the design and that was
probably best shown by the fact that
we made the first runway flights in a
35 knot, 30 degree crosswind. Mike
made the first flights and had no trouble at all keeping the airplane going
straight. On my first lift-off, I just sat
there fat, dumb and happy, doing nothing on the rudders, and let the airplane
drift across the runway. The next time
I paid more attention and had no trouble. Both of us were amazed how well
the Boomerang handled a crosswind."
Two days later, on June 19, Burt
and Mike made the first flight out of
the pattern. They began working
through their test card, but had to cut
the flight short when the oil temperature on one engine began to rise. The
landing was uneventful, but on rollout
the left main gear suddenly retracted.
Mike, who was flying, held the airplane straight as long as he could with
the right main brakes, but when they
began to fade, the Boomerang veered
off the runway and ran out into the
desert sand. Unfortunately, the nose
gear and right main were wiped out
when they plowed into a concrete base
for a runway light. . . and next came a
berm that nearly put the airplane up on
its nose and over on its back. It didn't,
however, and when the stricken bird finally came to a halt, Burt and Mike
just sat there for a second contemplating the unthinkable: "42 days until
Oshkosh '96, and here we sit on our
belly in the sand and dust!"
Burt admits that when he climbed
out of the Boomerang and saw the
curled prop blades and what appeared
to be structural damage to the bottom
of the fuselage and boom, he resigned
himself to hauling the airplane back to
its hangar, locking it up and forgetting
about making Oshkosh '96. In fact, he
later had it aimed in that direction
when one of his employees ran out and
said, "Don't put it down there, it's not
air conditioned and we can't work on
it." Real friends are always there when
you need them most, and Burt quickly
found that his were not going to let
him give up on his dream of flying the
Boomerang to Oshkosh.
When the airplane was brought back
into the shop, cleaned up and thoroughly examined, the s t r u c t u r a l
damage was found to
be largely limited to
the nose gear and
right main. Ironically,
the left main that had
retracted was undamaged. The damage to
the carbon fiber structure turned out to be
largely superficial,
and, in fact, had held
up a lot better than the
metal parts. The right
main gear leg, which
was a very sturdy
welded steel tube component, was literally
bent around the bottom of the carbon fiber
bulkhead behind it,
with nothing more
than scratched paint
on the bulkhead!
The engines, of
course, were the biggest
question mark. The
mixtures had been
pulled and the fuel shut
off before the airplane
went off the runway, -'
but they were still windmilling when they Burt Rutan with his EAA Freedom of Flight Award, presentbegan chopping sand. ed at Oshkosh '96 for his lifetime of aviation and space
The brand new Mc- achievements.
Cauley props that had ________
been initially installed
were junk when they
jerked to a stop, but it remained to be off the time, and it was during the next
seen whether the engines had been ru- two weeks that they were to learn that,
ined. Fortunately, they checked out O.K. indeed, the Boomerang was quite a re— very likely because it was sand the markable airplane. By the time he
airplane had bellied into — so it was arrived at Oshkosh, Burt was comback to all-night work sessions to get the pletely pumped . . . more excited about
Boom repaired in time to fly off its test a new design than we've seen him
time and get to Oshkosh by opening day. since the VariEze days. Though unWhat caused the gear collapse? It planned, he ended up spending much
turned out that the left main was not of his forum time talking about the
going completely over center in the Boomerang, so we'll give Burt the last
down and locked position, even though word by printing some of his comBurt and Mike were getting three ments here.
"The Boomerang is, dynamically,
greens in the cockpit. Amazingly, the
gear had held the airplane up during the most conservative airplane I've
the five crosswind runway flights made ever designed. It has twice the directwo days before, but simply gave way tional stability of any airplane I've
this time. Needless to say, a rework of ever built. In the air, you don't need to
the gear was the first order of business use the rudders at all. You can keep
your feet on the floor, even with an enwhen the repairs began.
On July 14, the Boomerang was gine out. It has good dihedral effect,
ready to fly again, and, thankfully, no too. You can raise a wing at any speed
further problems were experienced. with the rudders. It has superb roll."
"The airplane doesn't have a stall
Burt, Mike, Doug Shane and Dick Rutan were among those who helped fly characteristic. We haven't tested the aft
SPORT AVIATION 27
JIM KOEPNICK
CG yet, but we have gotten just little airplane. It flies beautifully. If you it is now. I would move the boom about
nibbles at full aft stick. It is kind of look at the trim tabs of the Boomerang, six inches further out. The airplane
Long-EZ like — you can fly it at full aft they are very small compared to those would be even more dynamically symstick at the CGs we've flown at so far." on most high performance twins. When metrical, and with the left engine
"If you're running full power on the you land it, you go out and look at the further out from the fuselage, it would
left engine and you've got the right tabs and they are all at zero. A be even quieter."
one feathered, you carry only about six Boomerang outruns a Turbo Baron by
(When asked if there were any plans
degrees of rudder. Now when you're about 30 knots and has twice the range. to produce the Boomerang . . . ) "No,
back at 80 knots, six degrees of rudder It flies about the same speed as a King I'm going to fly it for several years,
is a very light force. If you run full Air 200, but has twice the range."
just like I did the VariViggen and Depower on the right engine and have the
Back to Burt again . . .
fiant, then decide what to do with it."
"If I build another Boomerang, I'll
left one feathered (at 80 knots), it takes
"This really is, I believe, the best
about 12 to 16 degrees of rudder. You make it even more asymmetrical than configuration for a light twin."
^
hardly notice the difference. It's still a
very light force, and nothing like most
Range & Speed Comparison
conventional high performance twins
Cruise at Best Altitudes
where you would be pushing on rudder
A^
as hard as you can."
*^x
During one of the forums, Mike
^
Melvill was called on to make a few p*240"^ ^
comments on the Boomerang's handling characteristics, and this is what
he had to say:
"For such an unsymmetrical-looking airplane, it flies perfectly
symmetrically. To a pilot it is a totally
symmetrical airplane, no matter what
he does. If he pulls an engine back, it
just takes the tiniest amount of rudder,
and either way it seems to be about exactly the same in feel. To me, the roll
response in either direction appears to
be identical. We have made no corrections to the aerodynamics of the
28 OCTOBER 1996
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9C0
1100
1300
1500
1700
Range With IFR Reserves ~ Nautical Miles
Baron 58P 6 seats 870 Ib fuel
Baron 58P 4 seats 1140 Ib fuel
• Boomerang 5 seats 1008 Ib fuel
Defiant 4 seats 650 Ib fuel
19 00
21 C
-O- Malibu 6 seats 708 Ib fuel
O Cessna 421 6 seats 1450 Ib fuel
-£r Duchess 4 seats 590 Ib fuel
-0- King Air C90 6 seats 2266 Ib fuel