Pitcairn Pcab Engine Wright Hp

the change in the rotor pylon from four legs to three legs, elimination of the outboard flying and landing brace wires on the wings, and a slightly shorter landing gear.

The fuselage construction was welded steel tubes of varying diameters and wall thicknesses. The aluminum tubing fuselage on the PCA-1 was abandoned because of the difficulty of repair. The longerons on the PCA-2 were the familiar square shape that Pitcairn had used on all the Mailwing airplanes. The forward part of the fuselage around the cockpits was built with single tubes forming "vees" and "N's" to carry the loads from the landing gear, the wings and rotor pylon. Aft of the cockpit, the open bays formed by the longerons and cross members, were braced with two 3/16" diameter steel tubes welded diagonally from corner to corner of the bay and crossing each other in the center of the bay in the form of an"X." The engine mount was not removable from the fuselage, but was welded on as an integral part. Provisions were made in the engine mounting ring to install rubber bushings to absorb the engine vibrations. Deep fairing was built onto the fuselage to make the widest point as wide as the overall diameter of the engine. The frame for the tail surfaces was also welded steel tubing. The main beams of the tail surfaces where the hinges attached were of eliptical tubes. The airfoil section was added to these surfaces by building up the shape with small diameter steel tubes welded together and into the assembly. The entire tail group was bolted down to the fuselage and was wire braced. The horizontal stabilizer assembly could be adjusted in flight to trim the autogiro with varying loads.

The fixed wings had a total span of thirty feet and were built up in two panels bolted to the fuselage at a large dihedral angle. An M3 airfoil was selected. The left and right panels were built of spruce and birch, the main beams being built-up box assemblies.

The rotor blades were generally rectangular in plan form. The chord of the blade was of two widths; the one outboard being larger than the inboard. Transitional section of increasingly longer ribs faired the inner, narrow chord to the wider outer chord. The tip was curved with its thickness tapering into a rather sharp edge at the tip. Drain holes were provided at several places along the trailing edge of the blade to ventilate the inside to expel any moisture that was present as the result of condensation. These holes also prevented air pressure being built up from the centrifugal pumping caused by the rotation of the blade. The outer chord width was 22 inches; the inboard 53A feet had a chord of only 14-25/32 inches, the transition required three feet from inner to outer. The main member was a round tube of 4130 steel, 2Vs inches in diameter straightened to a close tolerance, heat treated and hand polished. Approximately fifty plywood ribs, an average of three inches apart, formed the airfoil. A Pitcairn #4 air foil was developed. It was a modification of the Goet-ingen 429. Ribs were routed from five-ply wood having alternate layers of mahogany and birch and were one quarter of an inch ihick. Each rib had a stainless steel collar riveted onto one side, and these in turn were fastened to the steel spar. Some of the early blades had these collars soldered to the spar, but this was later changed to spot welding. The welding process was especially developed by Pitcairn engineers so that the maximum strength in the weld could be developed without reducing the strength of the spar tube in the process. The blade was covered to a point just aft of the spar tube with thin plywood that had been preformed to the leading edge shape. The trailing edge was formed into a stainless steel "vee" of thin sheet which was nailed to the ribs on earlier models. Later a steel tail was formed for each rib and the wood rib cut off blunt about three inches from the end of the rib. The stainless steel trailing edge was provided with slip joints so that one section of the trailing edge telescoped into the other if the blade flexed fore and aft. As the entire blade was finished in doped fabric, the slip joints were covered with small leather patches so as not to wear out the trailing edge fabric. The fabric was held down to the ribs by rib stitching in the same manner as an airplane wing.

Each blade was attached to the hub through a flapping hinge which permitted the blade to flap up and down in balancing the forces of lift and centrifugal tension. The result of the two forces caused the blade to assume a "coning angle" above the horizontal. This angle varied, depending on whether the blade was advancing into the air stream or retreating from it. Just outboard of this flapping hinge a vertical hinge was installed. This permitted the blade to lag back as the drag was higher going into the air stream and to move forward as the drag decreased while the blade traveled with the airstream. To somewhat control the "hunting" of the blade as it traveled around the circumference of its circle, the blades were connected together with a steel cable about eight feet from the center of rotation. To prevent heavy shock loads in the blades as

'["he tail group for the Pitcairn PCA-IA with the horizontal tail in The tail group for the Pitcairn PCA1-A with the horizontal tail the normal position, (Pitcairn Photo) deflected as it would be to deflect the air through the rotor for aerodynamic rotor start. (Pitcairn Photo)

'["he tail group for the Pitcairn PCA-IA with the horizontal tail in The tail group for the Pitcairn PCA1-A with the horizontal tail the normal position, (Pitcairn Photo) deflected as it would be to deflect the air through the rotor for aerodynamic rotor start. (Pitcairn Photo)

they did their leading and lagging, a hydraulic shock absorber which was actually a reworked hydraulic door closer was installed between the cable and the blade spar. At the hub, on either side of each vertical hinge pin, two rubber blocks were installed to take up the shock if the blades were put in motion with their hydraulic damper at the extreme end of its travel. To prevent the blades from dropping all the way down on their flapping hinge and striking the aircraft when they were at rest or slowing down. A "droop" cable was run from a small cone or tower mounted on top of the hub to a point just inboard of the lead-lag damper.

The hub itself was mounted on bearings which were in turn mounted on a stationary axle or mast. This mast was fitted into the tripod or "pylon" which attached to the fuselage and lifted the autogiro into the air when the rotor provided sufficient lift.

The landing gear was similar to the PCA-1. The main gear was originally fitted with 30x5 high pressure tires which were changed to "semi-balloon" 850x10 tires. The tread was widened to thirteen feet, six inches. The bracing arrangement was the same as the PCA-1. A long-travel oleo shock strut was used. As in the PCA-1, the tail landing gear was a full-swiveling tail skid with rubber cord shock absorber.

The PCA-2 employed a mechanical rotor starter to bring the rotor up to the necessary takeoff rpm. This was mounted on the pad normally used by the engine starter. This required another means of starling the engine. A "Heywood Products" air starter injected compressed air directly into the engine cylinder. Air forced the piston down and turned the propeller to start the engine. A small air compressor mounted on the accessory pad developed 500 psi air pressure which was stored in a small tank. When released with a handle in the cockpit, air was delivered to the proper eylinder(s) in the firing order. Priming fuel, if used, was injected into the air line with a primer. No electrical system was installed. If position lights were desired, a dry "hot-shot" battery powered the lights. The battery was not rechargeable.

The fuel system consisted of two tanks. One 13-gallon tank just ahead of the passengers supplied fuel to the engine by gravity. Another 39-gallon tank was installed just below the cockpit floorline (actually under the passenger's seat). An engine-driven fuel pump kept the gravity tank full as long as fuel was available in the 39-gallon tank. All the while fuel was being delivered to the gravity tank a fuel pressure gauge in the cockpit showed fuel pressure. When the main tank fuel was exhausted, fuel pressure dropped to zero. The engine would continue to run because fuel was arriving from the gravity tank. The small tank had no fuel quantity gauge. It was necessary to constantly scan the pressure gauge because at the second the needle dropped to zero the upper tank was full for the last time. It was considered that a "safe" twenty minutes fuel remained with time to make a landing. The quantity gauge on the main tank was not a constant-reading type. It was necessary to pull a plunger out of the instrument panel and release it. This caused the fuel quantity to show on the quantity gauge.

The engine oil tank carried six and one half gallons and was mounted on the fire wall.

A conventional control stick rising from the floor operated the elevators and ailerons for pitch and roll control. Rudder pedals gave yaw control through a rUdder at the rear of the fuselage. All controls were cable operated.

Just inboard of each rudder pedal was a similar pedal which operated the mechanical

Pitcairn Autogyro PlansPitcairn Fuel Gauge

Pitcairn PCA-2 accident at an air show in Philadelphia in 1932, The pilot had just demonstrated ii "dead stick" landing to the aowi He took off with the fuel shut off. Enough fuel was in the lines and carburetor to get the autogiro airborne. The pilot turned the fuel 011 when the engine stopped and stroked the wobble pump. The engine came back on at full throttle, rolling the autogiro onto ifs side. (Pitcairn Photo)

Pitcairn Mail Wing Plane
Pitcairn PCA-2 taking off from a dock in New York City. (Pitcairn Photo)

wheel brakes using a cable. It was necessary to move one's feet from the rudder pedals to the brake pedals when taxiing or taking off when brake or rudder control was needed. The Mail-wing used the same system. It became critical on the Mailwing for the pilot to slide his feet to the proper pedal at exactly the right time on takeoff as the rudder became active and on the landing as it became useless, it was not as critical on the PCA-2 with its nearly-zero landing speed.

The PCA-2 came through the same factory, was groomed by the same fine craftsmen, and was designed by the same engineers as the Mail-wing suit had a family resemblance. But, as said earlier, it was learned from the experience at Pitcairn with the Cierva C-8 that the autogiro should not be a conventional airplane with rotor on top. It was built, like the Mailwing, to be flown by professional pilots. It proved to be a fine aircraft and saw service for many years with the Horizon Company, Fairchild Aircraft Company, Morgon Oil Company, Tri-State Airways, Champion Spark Plug Company, Standard Oil Company, Beech Nut Standard Oil of Ohio, Detroit News, Pure Oil, Silverbrook Coal, as an advertising tool of Lee Tire Company, and others. The US. Marine Corps purchased a

PCA-2 designated the XOP-1 and gave it service tests in Nicaragua. They thought it had some attributes, however, fitted with military gear very little payload was available. No further orders were forthcoming.

Among the PCA-2's early accomplishments was a flight across the United States when this was still a feat for fixed wing aircraft, an early flight across the straits of Florida to Cuba, and after installation of a special auxiliary tank on across Central America. One PCA-2 was looped as an everyday attraction by an airshow. Using the PCA-2 as a camera platform several newspapers were able to bring back unusual news pictures, among them the pictures of the ocean liner Moro Castle burning off the east coast of New Jersey on a very foggy day. One PCA-2 was landed and taken off from the White House lawn by Jim Ray when Harold Pitcairn was presented with the Collier Trophy by President Herbert Hoover.

The other^ariations of the PCA-2, differing only in the engine that was installed, were produced but not in quantity. A PCA-3 mounted a Pratt and Whitney Wasp Jr. engine, delivering 300 hp. The PA-21 used a Wright R-975 plant with 450 hp. In all, about 24 of all of the PCA-2

Photographs New York 1930
PCA-2 Pitcairn Autogiro over New York City, 1930. (Aero Service/Pitcairn Photo)
Windmill Plane

The author pulling Ihe Pitcairn PCA-2 Autogiro up at Ihe end of a crop dusting run When the dust hopper gate is shut, the dust cloud under the autogiro will magically drop hack into the crop field the autogiro has just left.

(GttS Pascjuarella Photo)

1930 Dusting Plane

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