(PART 2 OF 2 PARTS)

A Design Study In Advanced Ideas By Anthony N. LaNave, EAA 18984 R.D. 5, E. State Road, Alliance, Ohio

points (3) and (4) in the extreme outboard wing rib. The navigation light (5) is attached to wing tip (1).

Continued from June SPORT AVIATION

Fig. 16 is a cross-section view of the wing spar prior to seam welding. A British designer, Mr. Duncanson, had a similar design. The spar he designed was of rolled Dural reinforced externally by corrugation or hat sections. The inner portion of the spar was utilized as a gas tank. The Dural ribs were riveted to the corrugations. The spar which I have designed and illustrated in Figs. 16 and 17 is of two halves, (1) of rolled 4130 steel with a small flange (5) turned outward at the seam joint. The corrugations (2) are placed internally and the sections of the corrugation (3) that touch the outer wall of the spar are electrically spot-welded at regular intervals throughout the entire length of the spar. Small strips of felt or antisqueak are adhered to the corrugation and spaced at regular intervals of one or two feet apart throughout the entire length of the inner wing spar only. This is to protect the gas tank that will be fully described in Fig. 21. Fig. 17 shows the two halves of the spar after being seam-welded by using the atomic process. The spar requires no heat-treating or normalizing. The wall thickness of the outer shell of the spar and corrugation should be determined by stress analysis.

Fig. 18 shows the typical attachment of the trailing edge in the aileron area to the spar. An extruded angle (2) is atomic-welded to the outer wall of spar (1) and correctly positioned by a jig so that it will pick up wing rib (6) of the aft portion of wing (3). Rib (6) is bolted to the extruded angle (2) by two bolts, one passing through each flat area of angle (2). Aileron (4) is attached to the aft portion of wing (3) by inserting piano wire in the mated hinge extrusion attached to aileron (4) and the aft portion of the wing. The aileron travel is 2/3 up to 1/3 down. This

ratio makes less rudder action permissible. Stainless steel cover plates (5) extend from the extruded angle (2) to the forward extruded angle as shown in Fig. 25. Fig. 19 shows the installation of wing tip (1). The wing tip (1) is attached to the outer flange of spar (6) and at 8

JULY 1965

Fig. 20 illustrates the installation of the right hand gas tank. Left hand tank and its installation is identical to the right hand. The gas tank (1) is of welded aluminum in the S.O. condition. One baffle (2) is placed in the center of the tank to restrict the flow of gasoline from one half of the tank to the other half. In this manner, if the plane makes a steep bank with a half supply of gasoline, the gasoline will be held in four spaces evenly distributed along the inner spar. This eliminates the danger of gasoline flowing to the low side of the plane, making it difficult to raise the lowered wing. The gas tank (1) is inserted into spar (4) and protected from chafing against the corrugations (2) in Fig. 16 by felt strips (4). The gas tank (1) has a metal disc (3) that is larger in diameter than the tank, welded to the outboard end of the tank. This will serve to fasten the tank from side movement and also serve as a spacer between the inner and outer wing-attach angles. Figs. 21 and 22 show methods of attaching the inner wing spar to the fuselage. Fig. 21 is a view looking aft and shows bulkhead (3). This view shows the location of the spar in respect to the bulkheads of the fuselage. Fig. 22 is a side view of the spar locating between stations (3) and (4). The sheet metal brackets (2) are riveted to bulkhead (3) and sheet metal brackets (6) are riveted to bulkhead (5). The support fitting (4) is of 4130 and atomic-welded to spar (1). Fitting (4) is bolted to the fuselage structure laterally at points (7) and vertically at points (8). Bulkhead (3) is not positioned vertical to the center line of the ship but is positioned off-vertical with the bottom of bulkhead (3) toward the front of the ship. To correct this condition, the artist placed block (9) to take up the gap after placing the spar. This would be overcome by extending the sheet

metal fitting to replace block (9). Figs. 23 and 24 show the method of attaching the motor mount to the wing spar. Fittings (2) and (3) as shown in Figs. 23 and 24 are atomic-welded to spar (1). Fittings (2) and (3) have bushings (6) and (7) welded into place and reamed to allow support for the attaching bolts. Upper motor mount fitting (4) and lower motor mount fitting (5) are bolted to fittings (2) and (3) through bushed holes (6) and (7). Left and right motor installations are alike. Fig. 25 illustrates the method of attaching the leading edge and trailing edge of the wing to the wing spar and also is a typical cross-section of the wing construction. The

leading edge (1) and trailing edge (2) are attached to spar (3) as described in Fig. 18. Fabrication of this wing is simplified by breaking down the wing into three separate parts. The leading and trailing edges would be easier to fabricate because the inner areas are more accessible. To service and repair, or periodically check this type of wing is more feasible than a conventional wing. Fig. 26 is an exploded view of the empennage group. Fig. 2 will show this assembly in perspective. The boom (1) is constructed of rolled Dural riveted to five bulkheads evenly spaced to maintain stress and contour. Stringers may be added to meet stress requirements. Having the tail cone (2) detachable at point (3) allows desirable accessibility for installation of the stabilizers (4), rudder tab and bumper assembly (6) and the rigging of tail surfaces (5), (6) and (7). The navigation light (9) is installed into the tail cone assembly (2). The stabilizer (4) and elevators (5) are interchangeable left or right. The elevator trim tab (7) is located in the left and right elevators. Control surface (5) serves as the elevator, rudder, or a combination of both, dependent on movement of the unit. Empennage surfaces (4) and (5) are placed at a 45 deg. angle from the horizontal plane. This angle tends to give the empennage group decided dihedral favorable for anti-spin characteristics. Ventral fin (8) is suggested as shown but installed only if proven necessary. Spins are easily overcome by twin-engine aircraft. Assembly (6) serves a dual purpose. It attaches to the boom and rotates on point (11). On one engine failure, the pilot can trim the plane by rotating assembly (6) from the cockpit by operating rudder trim tab control (1) as shown in Fig. 5 and its installation in Fig. 1. Assembly (6) also serves as a bumper on nose-high landings. A small roller (10) similar to a fiber roller skate wheel would prevent excessive wear. Assembly (6) is internally braced by a welded steel tube structure. Dural skin forms the external shape and contour. Fig. 27 is a cross-sectional view of the control unit that actuates the novel tail design as described in Fig. 26 and shown in Fig. 2. The control unit is located at and attached to station (5) bulkhead, as shown in Fig. 11. Installation of the control unit in the fuselage is shown in cutaway in Fig. 1. The two castings (1) are bolted to station (5) bulkhead and suspend the control unit between them. The control unit is composed of two assemblies. Assembly (4) is formed by welding two steel tubes (3) to steel sleeve (2). Assembly (5) is formed in the following manner. The steel-formed rudder horn (8) and steel elevator horn (10) are bolted to steel ring (6) which is welded to hollow steel shaft (7). The control unit is complete when hollow steel shaft (7) is inserted into hollow steel sleeve (2) and secured there by retaining collar (13). Assembly (4) can only revolve on axis X-X. Rudder cables attach at point (11). The Dural push-pull tubes to the elevator bell cranks attach at point (10). The elevator push-pull tube from the control unit to the pilots' control column attaches to a swivel-type clevis (12).

Fig. 28 is a perspective view and best suited to describe the operational function of the control unit. Fig. 28, in relation to the airplane, is to be viewed looking aft. for clarification purposes, the control surface (5) in Fig. 26 will be referred to as an "elevudder." The first operational function to be explained will be elevator control. The Dural push-pull tube (1) is a direct interconnector from the base of the control column in the cockpit to point (12) at the control unit. The Dural push-pull tube (2) is a left hand direct interconnector from point (10) of the control unit to the bell crank at the base of the left "elevudder." Tube (3) is a right hand assembly and serves the same purpose as tube (2). The nose of the airplane is raised

by the pilot pulling back on the control wheel in a conventional manner, causing tube (1) to move forward. This action directs the control unit to revolve on X-X axis, causing tube (2) and tube (3) to move forward an equal distance. Tube (2) and tube (3), being pinioned to bell cranks attached to the base of the "elevudders", will cause the left and right "elevudders" to revolve in an upward and inward motion, causing the tail to go downward and nose to raise upward. Rudder control is accomplished in the following manner. Left rudder cable (4) and right rudder cable (5) are direct interconnectors between the rudder pedal assembly in Fig. 8 and point (11) on the control unit. For a right turn, the pilot depresses the right rudder pedal, causing cable (5) to move forward and cable (4) to move aft. This action directs the control unit to revolve on Y-Y axis, causing tube (3) to move forward and tube (2) to move aft. Tube (2) and tube (3), being pinioned to bell cranks attached to the base of the "elevudders", will cause the right "elevudder" to revolve downward and outward, and the left "elevudder" will revolve in an upward and inward motion, moving the tail to the left, causing the nose of the airplane to turn right. The control unit can revolve on X-X and Y-Y axis simultaneously. The pilot can select the "elevudders" to function as elevator control, rudder control, or any combination of both. SUMMARY —GENERAL DESCRIPTION Topic A

A low manufacturing cost is a definite factor to consider on the basis of commercial aviation competition. Special attention has been given to the following items: 1. Tooling is approximately 12 percent of the initial cost of the average lightplane. Tool design personnel have stated that this design would allow below-average tooling costs. (Continued on next page) SPORT AVIATION

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DESIGN STUDY . . .

(Continued from preceding page)

2. Fabrication . . . sub-assembly of this design could be

similar to the planning found effective for military aircraft. Interchangeability must be maintained.

3. The final assembly phase could be expedited by omitting large assemblies. For example all cabin area adjustments and installations would be completed prior to installing the plastic wind breaker. Topic B

The ease of serviceability and low cost of maintenance are essential. The omitting of any hydraulic system or large electrical actuating units lower maintenance costs. Quick change of battery, radio and other equipment without major rework are desired by the average plane owner. Topic C Design in general:

1. Controls . . . the outer wings have ailerons provided full length of their trailing edges. This large aileron surface allows desirable aileron control at "near stall" speeds. The entire aileron can be "drooped" and utilized as a large flap surface and still maintain aileron control. The Stinson L-5 "Sentinel" employed this design. As previously described, no rudder control will be necessary during flight. The brake system is actuated by depressing only one brake pedal. Full travel of the brake pedal will operate both brakes. Half travel and a movement of the control wheel to the left or right will automatically select either left or right brake for taxiing. 2. Power plants . . . two 60 hp Lycomings were intended for this two-place design. Two 80 hp Lycomings were intended for the four-place plane of this design. Fig. 2 illustrates the ease of accessibility to the power plants by installing hinged cowling fastened down to the wing area by Dzus buttons. Engine odors, noise and vibration have been removed from the cabin area. Propeller blast is removed from the nose of the plane and placed more efficiently as a pusher. This gives the tail surfaces quick response to control. The tear-drop shape of the fuselage allows the power plants to be placed very close to the center line of the airplane, thereby creating one of the factors allowing this design to maintain flight on one engine.

3. Cabin area . . . no step is required to enter or leave the cabin because the seats are at hip level to the

SAFETY U.S. GENERAL AVIATION LANDING GEAR EXTENSION

Many accidents occur when the normal landing gear system becomes inoperative and the pilot is not familiar with the operation of the emergency gear extension system. Know your emergency landing gear procedures and help prevent accidents. REMEMBER You may have to operate the alternate landing gear extension system on your next flight. Civil Aeronautics Board

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JULY 1965

average person. Left and right doors are provided. The visibility offered is practically unlimited. The head rests and seat backs can be adjusted for comfortable tilt. Seats can be adjusted fore and aft for proper distance to the rudder pedals. The seat cushions can be removed if a seat-pack type of parachute is desired. Safety belts roll out of sight when not in use merely by tugging and releasing, similar to a

window shade principle. Each seat contains two arms folded up that can be released and dropped to form arm rests. Fluorescent spotlights could be used to accentuate the luminous instruments for night operations. The landing light is installed forward of the nose landing gear. The plastic nose assembly is made in four pieces and can easily be changed. Fairing is provided and installed for aerodynamic purposes over the area where the boom is attached to the fuselage. *

ALERT OLD PILOTS AND BOLD PILOTS

You have no doubt heard it stated that there are many old pilots, but very few old, bold pilots. One very important factor in eventually attaining the status of an old pilot is an understanding of the relationship of alcohol to pilot skill and judgment. Alcohol, even in small amounts, has an adverse effect upon both. Avoid it for at least 24 hours before flying. REMEMBER Alcohol decreases pilot judgment, attention, vision and neuromuscular coordination. Altitude increases these effects. While alcohol may make you a bold pilot, it can prevent you from becoming an old pilot. Civil Aeronautics Board