PROPOSAL FOR A GOODYEAR RACER

By Don S. Mitchell


(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 U-2 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:  mitchellwing@earthlink.net or on the web:
home.earthlink.net/~mitchellwing/.  Also see his mini-autobiography.)

DON MITCHELL SHORT BIO

Don Mitchell is a veteran of the aviation industry, thoroughly trained and schooled in engineering and construction.
     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.

INTRODUCTION

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 conventional design.
     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 roadable airplanes.
     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.

DSM

SPECIFICATIONS

Top Speed                                              245 M.P.H.
Landing Speed                                         55 M.P.H.
Engine                                                    Continental C-85
                                                                 85 H.P. at 2570 R.P.M.
Pusher Installation
Span                                                           18 feet
Area                                                            72 Sq. Feet
Sweepback                                                40 Degrees
Total length                                                  9 Feet
Nacelle height                                           43 Inches
Weight empty                                         400 lbs. **
  Ballast                                                     100 lbs. **
Landing Gear                                          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.

CONSTRUCTION

MATERIAL:

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?

Because,

. . . 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 
       lasting publicity;

. . . 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 much more.
     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 spinner.
      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:

......................Lightplanes

......................Roadable Aircraft

......................Sailplanes

......................Executive Transports

     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.
     EXTERNAL AILEVATORS 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 of attack.
     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.

COST BREAKDOWN

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.................................................................... $60.00
     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 cost.

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.

4. PROPELLERS...............................................................$800.00
     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 molding company.

6. LABOR - SHOP - MACHINERY.................................$3,300.00
     This is a small ship and the room required for construction would be minimal.
 

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