(PART 2 OF 2 PARTS)

Continued from June SPORT AVIATIONFig. 16 is a cross-section view of the wing spar prior

to seam welding. A British designer, Mr. Duncanson, had asimilar design. The spar he designed was of rolled Duralreinforced externally by corrugation or hat sections. Theinner portion of the spar was utilized as a gas tank. TheDural ribs were riveted to the corrugations. The sparwhich I have designed and illustrated in Figs. 16 and 17is of two halves, (1) of rolled 4130 steel with a smallflange (5) turned outward at the seam joint. The corru-gations (2) are placed internally and the sections of thecorrugation (3) that touch the outer wall of the spar areelectrically spot-welded at regular intervals throughoutthe entire length of the spar. Small strips of felt or anti-squeak are adhered to the corrugation and spaced at reg-ular intervals of one or two feet apart throughout the en-tire length of the inner wing spar only. This is to protectthe gas tank that will be fully described in Fig. 21.

Fig. 17 shows the two halves of the spar after beingseam-welded by using the atomic process. The spar re-quires no heat-treating or normalizing. The wall thicknessof the outer shell of the spar and corrugation should bedetermined by stress analysis.

Fig. 18 shows the typical attachment of the trailingedge in the aileron area to the spar. An extruded angle(2) is atomic-welded to the outer wall of spar (1) and cor-rectly 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 theextruded angle (2) by two bolts, one passing through eachflat area of angle (2). Aileron (4) is attached to the aftportion of wing (3) by inserting piano wire in the matedhinge extrusion attached to aileron (4) and the aft portionof the wing. The aileron travel is 2/3 up to 1/3 down. Thisratio makes less rudder action permissible. Stainless steelcover plates (5) extend from the extruded angle (2) to theforward extruded angle as shown in Fig. 25.

Fig. 19 shows the installation of wing tip (1). The wingtip (1) is attached to the outer flange of spar (6) and at

ADesign Study

InAdvanced Ideas

By Anthony N. LaNave, EAA 18984R.D. 5, E. State Road, Alliance, Ohio

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

Fig. 20 illustrates the installation of the right handgas tank. Left hand tank and its installation is identicalto the right hand. The gas tank (1) is of welded aluminumin the S.O. condition. One baffle (2) is placed in the cen-ter of the tank to restrict the flow of gasoline from onehalf of the tank to the other half. In this manner, if theplane makes a steep bank with a half supply of gasoline,the gasoline will be held in four spaces evenly distributedalong the inner spar. This eliminates the danger of gaso-line flowing to the low side of the plane, making it diffi-cult to raise the lowered wing. The gas tank (1) is insertedinto spar (4) and protected from chafing against the cor-rugations (2) in Fig. 16 by felt strips (4). The gas tank(1) has a metal disc (3) that is larger in diameter thanthe tank, welded to the outboard end of the tank. Thiswill serve to fasten the tank from side movement and alsoserve as a spacer between the inner and outer wing-attachangles.

Figs. 21 and 22 show methods of attaching the innerwing spar to the fuselage. Fig. 21 is a view looking aft andshows bulkhead (3). This view shows the location of thespar in respect to the bulkheads of the fuselage. Fig. 22 isa 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-weldedto spar (1). Fitting (4) is bolted to the fuselage structurelaterally at points (7) and vertically at points (8). Bulkhead(3) is not positioned vertical to the center line of the shipbut 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 placingthe spar. This would be overcome by extending the sheetmetal fitting to replace block (9).

Figs. 23 and 24 show the method of attaching themotor mount to the wing spar. Fittings (2) and (3) as shownin Figs. 23 and 24 are atomic-welded to spar (1). Fittings(2) and (3) have bushings (6) and (7) welded into place andreamed to allow support for the attaching bolts. Uppermotor 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 leadingedge and trailing edge of the wing to the wing spar andalso is a typical cross-section of the wing construction. The

8 JULY 1965

leading edge (1) and trailing edge (2) are attached to spar(3) as described in Fig. 18. Fabrication of this wing is sim-plified by breaking down the wing into three separateparts. The leading and trailing edges would be easier tofabricate because the inner areas are more accessible. Toservice and repair, or periodically check this type of wingis 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 bulkheadsevenly spaced to maintain stress and contour. Stringersmay be added to meet stress requirements. Having thetail cone (2) detachable at point (3) allows desirable ac-cessibility for installation of the stabilizers (4), rudder taband bumper assembly (6) and the rigging of tail surfaces(5), (6) and (7). The navigation light (9) is installed intothe 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 sur-face (5) serves as the elevator, rudder, or a combinationof both, dependent on movement of the unit. Empennagesurfaces (4) and (5) are placed at a 45 deg. angle from thehorizontal plane. This angle tends to give the empennagegroup decided dihedral favorable for anti-spin character-istics. Ventral fin (8) is suggested as shown but installedonly if proven necessary. Spins are easily overcome bytwin-engine aircraft. Assembly (6) serves a dual purpose.It attaches to the boom and rotates on point (11). On oneengine failure, the pilot can trim the plane by rotatingassembly (6) from the cockpit by operating rudder trimtab control (1) as shown in Fig. 5 and its installation inFig. 1. Assembly (6) also serves as a bumper on nose-highlandings. A small roller (10) similar to a fiber roller skatewheel would prevent excessive wear. Assembly (6) is in-ternally braced by a welded steel tube structure. Duralskin forms the external shape and contour.

Fig. 27 is a cross-sectional view of the control unitthat actuates the novel tail design as described in Fig. 26and shown in Fig. 2. The control unit is located at and at-tached to station (5) bulkhead, as shown in Fig. 11. Instal-lation of the control unit in the fuselage is shown in cut-away 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 hollowsteel shaft (7). The control unit is complete when hollowsteel shaft (7) is inserted into hollow steel sleeve (2) andsecured there by retaining collar (13). Assembly (4) canonly revolve on axis X-X. Rudder cables attach at point(11). The Dural push-pull tubes to the elevator bell cranksattach at point (10). The elevator push-pull tube from thecontrol unit to the pilots' control column attaches to aswivel-type clevis (12).

Fig. 28 is a perspective view and best suited to de-scribe 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. 26will be referred to as an "elevudder." The first operationalfunction to be explained will be elevator control. TheDural push-pull tube (1) is a direct interconnector fromthe base of the control column in the cockpit to point (12)at the control unit. The Dural push-pull tube (2) is a lefthand direct interconnector from point (10) of the controlunit to the bell crank at the base of the left "elevudder."Tube (3) is a right hand assembly and serves the samepurpose as tube (2). The nose of the airplane is raised

by the pilot pulling back on the control wheel in a con-ventional manner, causing tube (1) to move forward. Thisaction directs the control unit to revolve on X-X axis, caus-ing tube (2) and tube (3) to move forward an equal dis-tance. Tube (2) and tube (3), being pinioned to bell cranksattached to the base of the "elevudders", will cause theleft and right "elevudders" to revolve in an upward andinward motion, causing the tail to go downward and noseto raise upward.

Rudder control is accomplished in the following man-ner. Left rudder cable (4) and right rudder cable (5) aredirect interconnectors between the rudder pedal assemblyin Fig. 8 and point (11) on the control unit. For a rightturn, the pilot depresses the right rudder pedal, causingcable (5) to move forward and cable (4) to move aft. Thisaction directs the control unit to revolve on Y-Y axis, caus-ing tube (3) to move forward and tube (2) to move aft.Tube (2) and tube (3), being pinioned to bell cranks at-tached to the base of the "elevudders", will cause theright "elevudder" to revolve downward and outward, andthe left "elevudder" will revolve in an upward and in-ward motion, moving the tail to the left, causing the noseof the airplane to turn right. The control unit can re-volve on X-X and Y-Y axis simultaneously. The pilot canselect the "elevudders" to function as elevator control,rudder control, or any combination of both.

SUMMARY —GENERAL DESCRIPTIONTopic A

A low manufacturing cost is a definite factor to con-sider on the basis of commercial aviation competition. Spe-cial attention has been given to the following items:

1. Tooling is approximately 12 percent of the initialcost of the average lightplane. Tool design personnelhave stated that this design would allow below-aver-age tooling costs.

(Continued on next page)

SPORT AVIATION 9

DESIGN STUDY . . .(Continued from preceding page)

2. Fabrication . . . sub-assembly of this design could besimilar to the planning found effective for militaryaircraft. Interchangeability must be maintained.

3. The final assembly phase could be expedited byomitting large assemblies. For example all cabinarea adjustments and installations would be com-pleted prior to installing the plastic wind breaker.

Topic BThe ease of serviceability and low cost of mainten-

ance are essential. The omitting of any hydraulic system orlarge electrical actuating units lower maintenance costs.Quick change of battery, radio and other equipment with-out major rework are desired by the average plane owner.

Topic CDesign in general:

1. Controls . . . the outer wings have ailerons providedfull length of their trailing edges. This large aileronsurface allows desirable aileron control at "near stall"speeds. The entire aileron can be "drooped" andutilized as a large flap surface and still maintain ail-eron control. The Stinson L-5 "Sentinel" employedthis design. As previously described, no rudder con-trol will be necessary during flight. The brake sys-tem is actuated by depressing only one brake pedal.Full travel of the brake pedal will operate bothbrakes. Half travel and a movement of the controlwheel to the left or right will automatically selecteither left or right brake for taxiing.

2. Power plants . . . two 60 hp Lycomings were intendedfor this two-place design. Two 80 hp Lycomings wereintended for the four-place plane of this design. Fig.2 illustrates the ease of accessibility to the powerplants by installing hinged cowling fastened downto the wing area by Dzus buttons. Engine odors,noise and vibration have been removed from thecabin area. Propeller blast is removed from the noseof the plane and placed more efficiently as a pusher.This gives the tail surfaces quick response to con-trol. The tear-drop shape of the fuselage allows thepower plants to be placed very close to the centerline of the airplane, thereby creating one of the fac-tors allowing this design to maintain flight on oneengine.

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

average person. Left and right doors are provided.The visibility offered is practically unlimited. Thehead rests and seat backs can be adjusted for com-fortable tilt. Seats can be adjusted fore and aft forproper distance to the rudder pedals. The seat cush-ions can be removed if a seat-pack type of parachuteis desired. Safety belts roll out of sight when not inuse merely by tugging and releasing, similar to awindow shade principle. Each seat contains two armsfolded up that can be released and dropped to formarm rests. Fluorescent spotlights could be used to ac-centuate the luminous instruments for night opera-tions. The landing light is installed forward of thenose landing gear. The plastic nose assembly is madein four pieces and can easily be changed. Fairing isprovided and installed for aerodynamic purposes overthe area where the boom is attached to the fuse-lage. *

S A F E T Y A L E R T

U.S. GENERAL AVIATIONLANDING GEAR EXTENSION

Many accidents occur when the normal landing gearsystem becomes inoperative and the pilot is not familiarwith the operation of the emergency gear extension sys-tem.

Know your emergency landing gear procedures andhelp prevent accidents.

REMEMBERYou may have to operate the alternate landing gear

extension system on your next flight.Civil Aeronautics Board

OLD PILOTS AND BOLD PILOTSYou 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 relation-ship of alcohol to pilot skill and judgment. Alcohol, evenin small amounts, has an adverse effect upon both. Avoidit for at least 24 hours before flying.

REMEMBERAlcohol decreases pilot judgment, attention, vision

and neuromuscular coordination. Altitude increases theseeffects. While alcohol may make you a bold pilot, it canprevent you from becoming an old pilot.

Civil Aeronautics Board

10 JULY 1965