|(NOTE: This was a paper written by Don
Mitchell (year unknown) and provided to TWITT by Richard Avalon of U.S.
Pacific, a distributor of Mitchell B-10 and
plans. It is a unique perspective on how Don thought about the use
of flying wings. For those interested in more on Mitchell designs,
you can contact Richard at:
firstname.lastname@example.org or on the web:
Also see his mini-autobiography.)
DON MITCHELL SHORT BIO
Don Mitchell is a
veteran of the aviation industry, thoroughly trained and schooled in engineering
He has co-designed and
built four of the outstanding sailplanes and power gliders in the country.
He has gone through
the “N.C.” procedure for approved type certificate for aircraft on seven
occasions and knows the workings of the Civil Aeronautics Administration
as well as many of the men in it. (ed. - This gives
some idea of the time period.)
Any references or additional
information regarding Mr. Mitchell’s background are available upon request.
The National Air Races
held annually at Cleveland, Ohio are a thrilling air show a valuable source
of aircraft improvement.
In 1946, to encourage
the design and development of light aircraft the Goodyear Tire & Rubber
Company created and spon-sored the “Goodyear Trophy Race” as part of the
National Air Races.
This booklet is submitted
in a sincere effort to obtain a sponsor and co-owner for the racer herein
described. It is a project that vigorously breaks away from the exhausted
It is not, however,
a flight of the im-agination, but rather one based on sound advanced aerodynamics
with practical data proving this type of aircraft is without parallel.
It is a project that
not only will admirably perform its main purpose of winning races, but
one that can be used as a nucleus for the design of cheap, safe, high performance
light aircraft, military pilotless jet drones, target ships, and practical
The reader will recognize
within these covers the outline of a project that will have an immediate
satisfaction and profit to the sponsor, designer, and to the aircraft industry
as a whole.
85 H.P. at 2570 R.P.M.
72 Sq. Feet
400 lbs. **
100 lbs. **
Tandem (Two Goodyear tires and wheels- 5.00-5)
Brake on rear wheel
No dihedral. No wing twist.
** 500 lbs. minimum weight empty required for Goodyear Race.
Sitka spruce spars and ribs. Three-ply plastic
bonded mahogany plywood skin.
Molded plastic bonded mahogany semi-monocoque
pod (nacelle). Plexiglass bubble canopy.
This airplane meets all of the regulations and
requirements for the Goodyear Trophy Race.
WHY THIS RACER?
. . . It is ultra modern and sensational in appearance;
. . . It has sparkling, exciting performance;
it has the ability to smash records;
. . . It has eye appeal and fires the imagin-ation
- qualities necessary for wide-spread and
. . . It has the “New Look” in aviation;
. . . It has terrific potentialities besides racing;
. . . It will be the first flying wing to compete
in the National Air Races;
. . . It has a basic control method destined to
bring a new era to aviation.
Winning races is the
prime purpose of a racing airplane. THIS flying wing will do that -- and
It will bring instant
publicity. Publicity poured out by papers, magazines, radio and newsreels;
by articles elaborating on the future possibilities of the ship, its natural
adaptability to civilian light planes, to military jet drones, to radio
target ships, to roadable aircraft; by articles on the fantastic simplicity
of the structure, on the safety and efficiency of the control method.
The publicity will continue
indefinitely because this racer stimulates and excites the imagination
with its many wonderful possibilities.
It will bring lasting
fame and honor to the sponsor for having foresight and vision to back a
ship years ahead in design.
The conventional airplane
has been developed to a remarkable degree in the past fifteen years, but,
it has been apparent for some time now that any real advancement must come
through a new overall design change; one that inherently embodies the characteristics
of lower drag, less structural weight, higher strength, simpler construction,
better blended design, and more compact form.
THIS PROPOSED RACER
HAS ALL OF THESE CHARACTERISTICS. They give to the ship more
speed, acceleration, maneu-verability, safety and lower cost. Characteristics
unobtainable at any price in conventional aircraft.
The heart of this racer
is the external control surfaces functioning as elevators and ailerons
(ailevators). Only through the use of these ailevators
can a compact, rugged, superbly blended design such as this be accomplished.
Only through the use
of ailevators can stability, safety, and controllability be accomplished
in a flying wing without sacrificing any high speed advantages.
The thin, swept, cantilever
wing, small cross section nacelle, tandem landing gear, and advanced cooling
arrangement of the Continental C-85 pusher engine installation gives this
ship a clear forty five mile per hour high speed margin over the best racers
built to date in the same class.
The super compact design
of the ship combined with the ailevator control makes for lightning and
precision maneuverability. Visibility is excellent due to the bubble canopy
and the absence of engine or bulky fuselage in front of the pilot. These
are of the utmost importance in aircraft.
The tandem landing gear,
aside from being more streamlined, is safer in taking off or landing. The
center of gravity is so low in relation to the ground contact points that
nosing over is eliminated even when landing with the brakes set.
A small skid midway out on the wing keeps the wing tip up off the ground
in ground handling.
The pusher engine installation
has better streamlining and higher propeller efficiency. The engine is
completely enclosed within the beautifully streamlined housing. Cooling
air is taken in at the leading edge of the wing, forced around the four
cylinders and ejected rearward through an annular slot at the propeller
A blower is installed
at the propeller end of the engine shaft for moving the air through the
ducts. This installation reduces cooling drag by more than 50% over conventional
methods. The air outlet, besides boosting propeller efficiency, helps to
control the boundary layer over the aft part of the nacelle resulting in
a marked reduction of the overall drag of the ship.
THIS RACER WOULD BE THE FIRST FLYING WING TO
PARTICIPATE IN ANY RACE IN THE U.S.A.
This flying wing racer
is not big EXCEPT IN PERFORMANCE total length being only about nine feet,
span eighteen feet, and the height to top of nacelle a mere forty-three
inches. This compactness is realized through making it a flying wing. Its
safety and top performance realized through the use of the AILEVATORS for
complete and exacting controls at low as well as high speeds.
The detailed design
and engineering have been meticulously worked out to a point where construction
of the actual ship could be started immediately.
Its spontaneous acceptance
will bring a new, a safer, a more practical era to aviation.
Will YOU be the sponsor?
THE MITCHELL EXTERNAL “AILEVATOR”
CONTROL METHOD FOR FLYING WINGS
Why haven’t there been built commercial versions
of flying wings? such as:
In the face of the many
basic aerodynamic and structural advantages of flying wings we still find
that commercial versions are not in existence. Here is the reason:
All of the control methods
used to date on flying wings are completely inadequate and incapable of
meeting the requirements for safe precision control and stability at both
high and low speeds.
It has always been a
simple problem to:
.......1. Make flying
wings controllable at low speeds (high angle of attack).
.......2. Make flying
wings controllable at high speeds (low angle of attack).
But, it has not been
possible to make the same flying wing safe and controllable at both high
and low speeds.
The Mitchell external
“ailevators” solve this basic problem in a simple, straightforward, efficient,
and direct manner, thereby removing all of the barriers standing in the
way of practical civilian flying wings.
Ailevators are external
central surfaces much smaller in area than the main wing. They are located
slightly below the trailing edge of the main wing and towards the tips.
There is a passageway for free airflow between the leading edge of the
surface and the trailing edge of the main wing.
Ailevators are not a
part of the main wing. They are independent surfaces located so that they
favorably influence the airflow over the main wing. At high and medium
speeds they cut down the drag on the main wing by smoothing out the airflow
leaving the trailing edge.
The external surfaces
are used as ailerons and elevators, hence the word AILEVATORS.
Wing tip stalling of
conventional flying wings takes place when the ship attains a moderate
angle of attack. When it occurs, elevator effectiveness is lost and, as
a result, the ship is unstable and uncontrollable. Slots, twist (washout),
or change in airfoil toward the tips do help this condition but do not
conquer it, and in themselves present serious structural, aerodynamic,
and production problems.
PREVENT WING TIP STALLING AT ALL ANGLES OF ATTACK without the use of
any of the complicated stall aids mentioned above. They do this partly
by controlling the boundary layer over the wing due to the favorable airflow
between the trailing edge of the wing and leading edge of the surface,
and partly by lowering aerodynamically the angle of attack of the wing
preceding the surface when the ship is brought up to medium and high angles
The technical aspects
of the control method are quite involved and will not be gone into at this
time, however complete information on the control system is available.
The money required for the construction of this
shin must and would be kept to a minimum. Naturally the smaller the in-vestment
the greater the profit in winning races.
The major cost items are:
1. AIR FRAME....................................................................
Mr. Mitchell has on
hand all of the material for the air frame except a few pieces of plywood.
He has pulleys, cables, rod ends, bolts, tubing and miscellaneous parts.
2. WHEELS, BRAKES, TIRES...............................................$50.00
For this racer these
items can be obtained through the Goodyear Tire & Rubber Company at
3. MOTOR, EXTENSION SHAFT.......................................$987.00
The Continental 85 h.p.
engine lists for $787.00. It is not necessary, however, to use a
new engine, and., if desired, a satisfactory
reconditioned one may be obtained at considerably less cost. The extension
shaft is a simple machine shop job and need not run over $200.00.
The maximum performance
of any ship is to a large extent determined by the choice of the propeller.
This ship, being a pusher installation, cuts down on the choice of available
propellers. However, the Sensinich Propeller Company has a wood pusher
propeller design that would be satisfactory to start with. The cost of
this propeller is $65.00 each. Several other propellers would have to be
made and tried in flight to obtain the one for maximum performance. For
this reason $800.00 is set aside for propellers.
5. PLEXIGLASS BUBBLE....................................................$50.00
The canopy is of simple
design and could be molded by Mr. Mitchell or he could have it done at
minimum cost through his personal connections with a leading aircraft plexiglass
6. LABOR - SHOP - MACHINERY.................................$3,300.00
This is a small ship
and the room required for construction would be minimal.