8/4/2019 P47N Performance Test

1/3

8/4/2019 P47N Performance Test

2/3

There were o control force reversal tendencies noticed over an IAS range of 150 to 400 mph. Below 150mph IAS and with high power, uncoordinated use of aileron and rudder will cause the rudder forces todecrease and in extreme cases will become negative. Recovery is accomplished by coordinating thecontrols, reducing the power and increasing the speed by nosing down.

D. Stability.

Qualitative stability tests were not made but there appeared to be no undesirable static ordynamic stability characteristics. With full external wing tanks the directional stability seemed decreased.

With full auxiliary tank the longitudinal stability appeared to be neutral especially in the climbing attitude,becoming normal again when auxiliary fuel is used up.

E. Trim.

Flight Adjustable trim tabs are provided for all three controls and there is sufficient trim for allnormal flying. Above 54 Hg manifold pressure, right rudder trim is insufficient for speeds below 150 mph IASbut the forces are not great and may be maintained by the pilot.

As in earlier model P-47s, large changes in trim are necessary for changes in airspeed.

F. Maneuverability and Aerobatics.

Maneuverability and aerobatic characteristics are similar to earlier P-47s in the cleanconfiguration. With wing tip tanks filled the rate of roll and radius of turn of the P-47N is poor. No aerobaticswere performed at the high gross weights (wing and belly tanks), but the rate of roll was slow for thiscondition.

G. Stalling Characteristics.

There was no bad stalling characteristics noticed on the P-47N. All stalls were preceded by slightbuffeting 6 or 7 mph above the stalling speed and as speed decreased the buffeting increased until the stallwhich usually resulted in dropping the left wing. There was no tendency to spin after a stall and the airplanewould recover by itself after airspeed was regained.

H. Longitudinal stability of the P-47N decreases with an increase in altitude and becomes objectionalat high altitudes.

I. Noise and Vibration.

The noise level of the P-47N was low for a fighter type of airplane and was not objectionable.Slight vibration was noticed at 2250 rpm but at rpms above or below 2250 rpm the vibration was negligible.

J. Approach, Landing and Wave-off.

Approach is made with 50% rated power, full flaps, 0 rudder and aileron trim and approximately5 nose up elevator trim. Recommended IAS for approach is 140 mph with a minimum of 120 mph. There isno ground looping tendencies due to the locked tail wheel. Going around is not dangerous but flaps should

not be raised below 400 ft. and then gradually.

K. Vision.

Visibility in taxiing, take-off and climb is poor but no worse than earlier P-47s. Landing visibility isgood with the exception of power landings. No distortion was noticed in the windshield, canopy or bullet-proofglass.

L. Cockpit Layout.

Access to the cockpit is made from the left side where suitable steps and handles are provided.Controls should be unlocked before entering cockpit because the control lock is a strap latch arrangementwhich extends across the bottom of the seat and would be difficult to unlock after the pilot is seated. Some

difficulty is experienced in unlocking controls before entering cockpit.

With few exceptions, the cockpit is similar to earlier P-47s. Pilots of D series Thunderbolts willfeel at home in the N model. In general, all the controls and instruments are well laid out for a fighter typeaircraft. Some of the differences noted from earlier model P-47s are:

8/4/2019 P47N Performance Test

3/3

The main switch panel is located on the left side of the cockpit, just above the flaps and landinggear levers. An internal wing fuel and oil quantity gages are provided, the auto-pilot controls and instrumentsare added to the front panel and the manual primer had been replaced by an electric switch.

The P-47N is better than average for comfort since the cockpit is large and does not cranp thepilot. Heating appeared normal although no long range flights at high altitude were made. Ventilation isprovided by two cold air inlets, one on each side of the cockpit just below the arms. However, at low altitudeson warm days the cockpit is too hot and air conditioning would be required to provide cool air under theseconditions. For long range flight and auto-pilot is provided and for leg comfort the rudder pedals may be

folded aft enabling the pilot to place his feet through the spaces thereby provided.

M. General Functioning.

Due to the high power consistently used during the tests, considerable maintenance trouble wasexperienced with this specific airplane. Some of the more common malfunctions were:

Oil leaks, exhaust collector rings burning off, tachometer generator leads breaking off and in oneinstance the valve push rods broke off. With the exception of one burned out generator no trouble wasencountered with the electrical and hydraulic system.

The emergency system for the extension of gear and flaps is satisfactory. No emergency systemis provided for the brakes, For bailing out, the canopy may be jettisoned.

V Performance Data

A. All performance data has been corrected to NACA standard atmospheric conditions. Observedflight test data for all tests are tabulated in Appendix II of this report. Performance curves corrected tostandard conditions are grouped in Appendix I of this report.

B. Airspeed Calibration.

Airspeed calibrations were obtained by flying with a P-51 pacer airplane and were run for each ofthe three drag configurations tested. The resulting curves are plotted in Figure I of this report. Althoughthere was a slight difference in calibration for the airplane with the auxiliary tanks installed it was less than 1mph and the position error correction of the P-47N airplane is given in the following table.