PIPER J3 CUB PERFORMANCE DATA ============================= [This information is copied from the 1946 J3C-65 owner's handbook.] FLYING HINTS The Piper Cub Special represents more than 15 years of diligent aircraft engineering and manufacturing experience. Its simplicity of design and construction, its low operating and maintenance costs, its inherent stability, ruggedness, and its outstanding safety and ease of flying, have made it the most popular airplane in aviation history. The Piper Cub Special is the time-tested product of millions of hours of flying under all conceivable conditions both in the military and in peace time. There are hints on starting, flying, stopping, and other related topics that are important to the owner who wants to conserve his airplane -- keep it in maximum airworthy condition -- and enjoy a full measure of flying satisfaction. First, each pilot should become familiar enough with his Piper Cub Special that he can accomplish a satisfactory pre-flight inspection. This check is simple and requires only a few minutes. See Section IX for check list. Daily check of airplane prior to flight should be the first in a number of safe flying habits the pilot should acquire. A. BEFORE STARTING ENGINE (1) Make routine check of gasoline supply. Visible fuel gauge is integral part of gas tank cap; it will not show number of gallons but will show proportion of fuel in tank by length of rod which extends upward from cap. A full tank of 12 U.S. gallons will be indicated by 11 inches of rod extending beyond cap. Keep gas gauge rod clean and smooth with crocus cloth for accuracy and freedom of movement. (2) Check oil level in engine sump by removing oil cap and gauge. Oil stick should indicate oil level up to index mark of 4 quarts. (3) Check freedom of movement of flight and engine controls. B. STARTING ENGINE (1) Chock wheels, or have occupant who is familiar with controls set brakes in cabin. (2) Ignition switch OFF. Verify. (3) Set throttle approximately 1/10 open. (4) Push fuel shut-off ON. (5) Turn propeller through several times. (6) Turn ignition switch ON. (7) Start engine by pulling propeller through with a snap. CAUTION -- Always handle propeller as if switch were "ON." Stand as far in front of propeller as possible. Use both hands and grasp one blad approximately midway from tip. Do not overgrasp blade. Do not wear long, loose clothing. Make sure footing is sure to preclude possibility of feet slipping. (8) If engine does not start, turn switch OFF. Turn primer knob to unlock, pull out, pump three or four times, then reseat primer and lock by turning in opposite direction. In extremely cold weather a few strokes of the primer as the engine starts will enable it to keep running. NOTE -- Avoid excessive priming as it causes raw gasoline to wash lubricating oil from engine cylinder walls. Do not prime warm engine. (9) Repeat starting procedures 6, 7. (10) If engine loads up and refuses to start, turn ignition switch "OFF,", open throttle wide and turn propeller through backwards several times to unload excessive gas mixture in cylinders. Then close throttle and repeat starting procedure. C. ENGINE WARM-UP (1) As soon as engine starts, advance throttle slightly to idle at 700 R.P.M. Check engine instruments. If oil pressure gauge does not indicate pressure within 30 seconds, stop engine immediately, check and correct trouble before any further operation. Oil temperature during operating should not rise above 200° F. and oil pressure should not fall below 30 pounds. With engine warm, idling speed should be 550-600 R.P.M. (2) Rev engine up to 2100 R.P.M. on both magnetos. Switch to LEFT and RIGHT magnetos. R.P.M. drop should not be over 75 R.P.M. CAUTION --Do not operate engine on either single magneto for more than 30 seconds at a time, as this tends to foul the non-operating spark plugs in the ignition circuit of the magneto that is switched off. D. STOPPING ENGINE (1) Never cut switch immediately after landing as this causes engine to cool too rapidly. (2) Idle engine, especially in high temperature operating conditions, for several minutes. It is advisable to switch to each magneto for 30 second intervals to allow gradual cooling of engine. This helps to prevent overheating of spark plug insulators and will lessen tendency for "after-firing." (3) Check for carburetor heat OFF during idling. E. TAXIING (1) Open throttle to start airplane in motion; then close throttle to a setting sufficient to keep airplane rolling. Do not keep throttle advanced so that it is necessary to control taxi speed of airplane with brakes. This causes unnecessary wear and tear on brakes and tires. (2) Taxi slowly (speed of a fast walk) controlling direction with rudder which is connected to a steerable tail wheel. Use brakes only for positive, precision ground control when necessary. (3) Taxi upwind with stick back; downwind with stick foreward. When ground winds are in excess of 15 M.P.H., turn into wind using ailerons in direction of turn; apply ailerons away from the turn when turning downwind. This procedure helps to prevent the wind "picking up" a wing during windy, gusty conditions. Always make ground turns slowly. F. GENERAL FLYING (1) For takeoff use full throttle, heading into wind. Airplane loaded will become airborne at approximately 39 M.P.H. Best climb speed is an indicated 55 M.P.H. (2) Indicated R.P.M. for cruising speed of 73 M.P.H. is 2150. Take-off R.P.M. is 2300. Do not fly at full throttle over 3 minutes. (3) Use CARBURETOR AIR HEAT when engine runs "rough" and tachometer shows drop in R.P.M. which may be due to ice forming in carburetor. Tachometer should recover to within 50 R.P.M. below normal when using carburetor heat. Push heater to "OFF" position, and if icing condition has been cleared, R.P.M. should return to normal. Continued use of carburetor heat will only cause increased fuel consumption and loss of power. (4) Maximum permissible diving speed is 122 M.P.H. G. APPROACH AND LANDING (1) Push carburetor heat ON prior to throttling back for glide, or for any other flight maneuver. (2) Glide between 50-60 M.P.H. depending upon loading of airplane and gust conditions. NOTE -- "Clear" engine by opening throttle gently, every 200-250 feet of descent during a long glide so that engine temperature will be maintained. Throttle action on the part of the pilot should be smooth and gentle at all times. H. PARKING AND MOORING (1) After termination of flight, enter flying time in aircraft and engine log books. (2) Turn ignition and fuel OFF. (3) Chcok the wheels of airplane. (4) If airplane is not to be flown for some time, it should be hangared or tied down. Use good quality 1/2" - 5/8" diameter rope. Secure to lift assist handle at aft end of fuselage; also at upper end of both front wing lift struts where they attach to wing. Make sure that rope passes between aileron cable and lift strut. Mooring ropes, when airplane is tied down, should have no slack. (5) Lock aileron and elevator controls by wrapping front seat belt completely around rear control stick, tighten and buckle. (6) Under excessively wind conditions, airplane should be tailed into wind for mooring. [Here is my older information.] These are the only numbers I could find. They are for a J3 Cub with an 85HP engine rather than 65 hp, so some adjustments may be necessary. The source is http://www.evergreenfs.com/planedata.htm Speeds ------ Best rate of climb (Vy): 65 mph (57 kt) Best angle of climb (Vx): 55 mph (48 kt) Cruise: 70 mph (61 kt) Never-exceed (Vne): 122 mph (106 kt) Best Glide (Vglide): 60 mph (52 kt) Stall (Vs): 38 mph (33 kt) Maneuvering (Va): 70 mph (61 kt) Approach: 50-60 mph (44-52 kt) Power ----- Take off: full Climb: 50 rpm below full Cruise: 2300 rpm Approach: 1200 rpm Practice stalls: 1200 rpm Distances --------- Take-off: 450-800 ft Landing: 200-800 ft Fuel ---- Total fuel: 12 gal US Usable fuel: 12 gal US Grade: 80/87 GPH: 5 gal US/hr