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Pilot`s Notes Airacobra Pilot`s Notes

Pilot`s flight operating instructions for ARMY MODEL P-39Q-1 AIRPLANE

8. ENGINE FAILURE DURING TAKE-OFF.

Should the engine fail during take-off, put the nose of the airplane down and maintain flying speed. Raise the landing gear if the ground is not level ahead and fully lower the flaps. Then turn the ignition switch off and land straight ahead.

ATTENTION

Drop belly tank or bomb before a forced landing.

NOTE

Dropping Belly Tank. - When It Is necessary to drop the belly tank In (light, pull the release handle and at the same time lift the airplane gently from the falling tank by pulling back slightly on the stick. DO NOT PULL THE NOSE UP SO SHARPLY THAT THE TAIL DROPS ENOUGH TO STRIKE THE TANK.

9. CLIMB.

The best climbing speed of this airplane is as follows:

a. Altitudes up to 5000 feet 162 IAS

b. Altitudes 5000 feet to 10,000 feet 160 IAS

c. Altitudes above 10,000 feet 158 IAS with a drop of one mph for every 1000 feet additional altitude.

10. FLIGHT OPERATION.

a. To increase engine power during flight, set the mixture control lever (figure 5) in the''AUTO-RICH" position, adjust the propeller control lever (figure 5) to the desiredrpm and Increase manifold pressure as desired.

b. To decrease engine power during flight, adjust the throttle (figure 5) to the desired manifold pressure, adjust the propeller control lever (figure 5) to obtain the desired rpm, and then readjust the mixture control lever as necessary.

11. GENERAL FLYING CHARACTERISTICS.

a. Fuel selection was noted "reserve tank" for "take-off." After take-off proceed as follows:

(1) After about 20 minutes switch to belly tank ("AUX")andrun it dry.

(2) Run "right tank" dry.

(3) Run "left tank" dry.

(4) Switch to "reserve."

NOTE

"Left tank" will partially refill in flight due to vent return lines.
WARNING    Never turn selector valve to "AUX," (belly tank) when it Is not installed.

b. In cruising flight, the following gages and their respective readings give the most satisfactory indication of the engine's performance:

RPM ............................................1600 to 2400

Oil Inlet Temperature.......................60°C (140°F) to 80°C (176°F)

Oil Pressure (Pounds Per Square Inch)..60 to 70

Coolant Outlet Temperature.................100°C (212°F) to 120°C (248°F)

CAUTION

In the event any of the above-mentioned opera, tion gages appear very Irregular, it is recommended that the engine be throttled down. Then, if the cause of the irregularity is not apparent, land the airplane and have the trouble investigated and corrected.

When flying with the auxiliary (or belly tank) it will be noticed that the airplane Is slightly unstable when making a sharp bank at slow speeds. It is therefore recommended that the pilot maintain his flying speed and avoid sharp turns and banks with auxiliary tank.

12. ENGINE FAILURE DURING FLIGHT.

Should the engine fall during flight the altitude at which the airplane is flying will greatly determine the action of the pilot.

Ignition switch, booster fuel pump and fuel selector mustbe turned "OFF." Drop belly tank or bomb before landing.

a. If flying at a reasonably high altitude, proceed as follows:

Judging from the landscape determine the best place to land and put nose of airplane down sufficiently to maintain flying speed 130 mph IAS to successfully reach point where landing Is to be made. The pilot must decide whether or not it is advisable to lower the landing gear.

If the field is rough, leave the landing gear retracted. If field is smooth, extend landing gear. If in doubt leave it retracted. Use full flaps and land straight ahead.

b. If the airplane is flying at a rather low altitude it is recommended that the pilot proceed as follows:

Ignition switch, booster fuel pump and fuel selector must be turned ''OFF."

Leave landing gear retracted, and keep nose of the airplane down to help maintain flying speed - 130 mph IAS. As the airplane nears the ground it is advisable to lower the flaps and land with as high an angle of attack as possible (that is, tail down).

13. STALLS.

This airplane has good stalling characteristics (about 105 mph flaps "UP" or 90 mph with flaps "DOWN"). The airplane will mush considerably at stalling speeds. The stall occurs first at the center section of each wing panel and progresses outboard. To recover, allow the speed to build up sufficiently or approximately between 130 and 140 mph so as to completely unstall the center section.

14. SPINS.

Deliberate spinning is not recommended. However, if a spin occurs, rapid recovery can be made as follows:

a. PRERECOVERY.

(1) Throttle must be off.

(2) Propeller control must be in the low rpm position.

(3) Stick full back.

b. RECOVERY.

(1) Apply full opposite rudder when spin is at its slowest.

(2) Wait until rudder effect is noticeable, then apply full forward stick and ailerons against the spin regardless of ammunition load in the wings.

c. The spin is usually oscillatory in rate, and it is mandatory that the opposite rudder be applied when the spin is at its slowest.

d. If the procedure above is followed, the airplane, will recover in one-half turn. If the procedure is not followed closely, the airplane may not recover.

15. ACROBATICS.

a. Normal loops, slow rolls and Immelmans are all done with ease.

b. Cage flight indicator before doing acrobatics.

16. DIVING.

a. It is necessary to trim nose heary when diTlng this airplane, otherwise the airplane will make a severe pull-out as speed is attained. Also when diving, the airplane will tend to yaw to the right, and left rudder must be used to overcome this. The maximum permissible diving speed is 523 mph. 475 mph is the maximum recommended indicated air speed.

b. To decrease the possibility of the engine malfunctioning and missing considerably, upon opening the throttle, after pull-out from POWER OFF DIVES, the following precautions will be rigidly observed:

"DO NOT CLOSE THE THROTTLE TO ALLOW A MANIFOLD PRESSURE OF LESS THAN 20 INCHES HG DURING DIVE."

WARNING

PULL-OUTS FROM DIVES ARE TO BE STARTED AT 10,000 FEET MINIMUM ALTITUDE.

17. NIGHT FLYING.

a. The operation of the fluorescent lights is as follows:

(1) For visible light for map reading, etc., shutters should be full open.

(2) For fluorescent light (invisible) to Irradiate instruments, rotate the knurled knob until the shutters are closed.

NOTE

PROPERLY SET FOR THIS POSITION (IRRADIATION OF INSTRUMENTS) THE INSTRUMENT PANEL AND THE INSTRUMENT FACES ARE NOT LIGHTED. ONLY THE MARKINGS (FIGURES, HANDS, POINTERS, KNOBS, ETC.) WILL BE VISIBLE.

b. When lowering the landing light a sharp nibbling on the control stick is felt. Do not lower landing light over 130 mph Indicated air speed.


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