Pilot's Operating Handbook for the Piper PA-22 Tri-Pacer

welded together to form a rigid structure. A number of highly stressed members are of chromemolybdenum steel (4130). Other members are of 1025 steel. Repairs to the fuselage can be made in the manner approved by the F.A.A. Advisory Circular 43.13-1, and repair facilities for this type of construction are available universally. The fuselage is made corrosion resistant by the application of a coat of zinc chromate, followed by a sealer coat of nitrate dope. A third coat of dope-proof lacquer is sprayed on the fuselage members wherever fabrics comes in contact with the structure. If the air- plane is to be used in salt water areas, the fuselage can be metallized prior to applying the zinc chromate and dope; at the same time the interior of the tubing is coated with linseed oil to prevent internal corrosion. The wing framework consists of riveted aluminum ribs mounted on extruded aluminum spars with tubular drag and compression struts and high strength stainless steel drag wires. Aluminum sheet is used to form the leading edge and the aileron false spar. An ash wing tip bow provides a light tough member which can withstand considerable wing tip shock without failing. The wings are attached to the fuselage at the wing hinge fittings on upper fuselage members, and by means of the lift struts which bolt to the lower fuselage members and to the wing spar fittings. The lift struts can be adjusted in length by turning in or out the forked fittings at the lower ends. This adjustment is used to set the rigging of the wings. Any lifting of the airplane at the struts should be done at the extreme end of the strut and not in the center, to prevent bend- ing the struts. 7 | SECTION The Piper Tri-Pacer IV. Landing Gear and Brakes: The Tri-Pacer main gear incorporates Cleveland 600x6 wheels, Model C-38500-H, fitted with hydraulic brakes, Model C-2000H-7, and 4-ply 600x6 tires. The brakes are actuated by a hand brake control located under the center of the instrument panel. The brake handle is connected by a cable with a master cylinder which is mounted under the pilot's seat. A parking brake valve is attached to the forward side of the firewall with the control located on the left side of the instrument sub-panel. In applying the parking brake, first pull the brake handle back, next pull out the parking brake control, then release the brake handle. To disengage the parking brake simply push in its control. Also incorporated in the main gear are hydrasorb shock units, consisting of automotive type hydraulic shock absorbers combined with light shock cords. The nose gear uses a rugged oleo strut bolted to the engine mount at the firewall. The nose wheel is the same as the main wheels except for the absence of a brake drum, and is Model C-38501-H. The nose wheel is steerable through a 40° arc by the rudder pedals which actuate steering rods attached to steering arms at the top of the nose wheel unit. 8 The Piper Tri-Pacer V. Control System and Empennage: SECTION 1 The units which make up the empennage are the fin, rudder, stabilizers and elevators. They are all constructed of tubular steel with steel channel ribs. The control surface hinges have bronze bushing inserts and should be oiled with light oil occasionally. Cad- mium plated steel tie rods brace the stabilizer to the fin and fuselage. The tail brace wires should not be used for lifting or handling the airplane. Caution must be exercised in using the stabilizers for lifting or lowering the tail of the airplane. The stabilizer adjusting mechanism is easily damaged by application of excessive handling loads on the stabilizer. On the Tri-Pacer, steering during ground handling should not be done with the rudder, which may become distorted if mishandled. A steering handle is provided with each airplane, anchored in the baggage compartment, and should be used for moving the plane on the ground. The Tri-Pacer is equipped with conventional dual wheel flight controls. The flap control handle is located between and ahead of the front seats. The flaps have three positions-up, one-half down, and full down. The full flap position is used for maximum effect in landing and take-offs, while the half flap position is used when inter- mediate results are desired. The stabilizer adjustment control is located overhead between the front seats and is connected to the stabilizer adjustment mechan- ism at the stabilizer by an endless cable. A permanently automatic tension adjustment, which. consists of an idler pulley held in place near the rear main pulley by a tension spring, maintains correct tension on the stabilizer cable and prevents cable slippage. The system normally requires no attention except for lubrication and inspection. In the control system of the Tri-Pacer, the rudder pedals are connected directly to the nose wheel for ground steering, and the aileron cables are interconnected with the rudder cables to provide automatically coordinated aileron and rudder controls for simplified handling in the air. The interconnection incorporates a spring, lo- cated behind the baggage compartment, and is arranged so that al- though in level flight a movement of the ailerons results in proper 9 | SECTION The Piper Tri-Pacer rudder action to give coordinated turns, still the controls can be crossed if desired to obtain slips or skids. VI. Fuel System: Two eighteen gallon fuel tanks located in the wings provide fuel storage in the Tri-Pacer. The tanks are drained individually according to the position of the fuel selector valve on the left forward cabin wall. The rear fuel line from the right tank has a low point under the right front seat at which point is located a quick drain gascolator. The drain in this gascolator, which should be checked frequently for water or sediment, is reached through an opening in the right landing gear belly fairing. An electric fuel gauge for each tank is located on the lower right side of the instrument panel. 10 The Piper Tri-Pacer SECTION The main fuel strainer, through which all fuel going to the car- buretor flows, is located on the lower left engine side of the firewall. It is provided with a quick drain and should be drained regularly. Fuel screens are provided at tank outlets, in the strainer and at the carburetor. The engine primer pump on the right side of the instrument panel takes fuel from the main gascolator and pumps it directly to all four cylinders of the engine. To prevent malfunctioning of the en- gine, the primer must be locked in at all times except when in use. An idle cut-off is incorporated in the mixture control so that full extension of the control stops the flow of fuel at the carburetor. The cut-off should always be used to stop the engine. An eight gallon reserve fuel tank which fits under the rear seat is available as optional equipment. The fuel from this tank is pumped by an electric pump under the co-pilot's seat to the fuel strainer for the right main tank. From the strainer the fuel passes up the main supply line to the right tank. To use the reserve fuel supply, first use the right tank until it is at least half empty, preferably completely empty; this must be done while sufficient fuel remains in the left tank to continue to operate the engine until the right main supply is replenished. When the right tank is half full or less, switch the selector valve to left tank and pull. the reserve fuel knob. The reserve fuel will then be pumped into the right tank, in a period of about 25 minutes. Then turn the reserve pump off. Fuel should not be pumped from the reserve tank to the right main tank while the selector valve is at the right tank position. VII. Electrical System: The master switch for the electrical system is located on the master switch fuse box under the left side of the pilot's seat. In the "up" position of this switch the main fuse is engaged; the “down” position is for the spare fuse, and the central position is "off". The starter button is located on the bottom of the master switch fuse box. The starter cannot be operated unless the master switch is on. Circuit breakers for the radio, lights and generator are in a bracket under the left side of the instrument panel. These units auto- 11 12 STABILIZER ADJUSTMENT CRANK CONTROL WHEELS AILERON HORN CONTROL COLUMN- ELEVATOR HORN -STABILIZER ADJUSTMENT MECHANISM AILERON HORN- SECTION The Piper Tri-Pacer AILERON & ELEVATOR CONTROLS TRI PACER