| Rate of climb is uncorrected for coolant shutter position as this correction involved a maximum of 2 to 3% change in rate of climb which is within the limits of experimental accuracy.
III. Condition of Aircraft Relative to Tests
All preliminary flight tests were conducted at the fighter configuration (wing racks installed but without rocket racks) at a take-off weight of 9484 pounds with c. g. at 26.3% MAC, MAC wheels down. This weight includes full fuel and oil, six .50 caliber machine guns and ballast for 1880 rounds of .50 caliber ammunition.
The airplane was equipped with a Packard built Rolls Royce model V-1650-9 engine, supplied with water injection for use at war emergency power, Bendix Stromberg PD18C-3A carburetor, and four bladed Aero-Products propeller H20-162-29M5, design No. 86892. All power figures are based on power curve from Eng. Spec. No. AC-10356 and MX100, dated 29 November 1944. At the present time the V-1650-9 engine has not been calibrated and all power curves are computed from calculated power curves.
All flights were made with wheels retracted, wing flaps neutral, coolant scoop automatic, canopy closed and mixture auto-rich.
IV. Flight Characteristics
A. Taxiing and Ground Handling
The ground handling characteristics of this airplane are very good, and directional control is easily maintained.
The tailwheel, when in the locked position, is steerable through a twelve degree angle which is desirable. It is conveniently unlocked by pushing the stick full forward.
The brakes operate satisfactorily and are effective when applied from all rudder positions.
Visibility straight forward is obstructed completely by the nose when in the three point position, but, in general, the visibility, as well as taxiing characteristics, is the most desirable of any airplane with conventional type landing gear.
Take-off characteristics are normal for this type airplane. The airplane tends to swing slightly to the left on take-off when the throttle is opened rapidly, however, sufficient trim is available to compensate for this. Sufficient trim is not available for maintaining the desired climbing speeds in high powered climbs.
Ground roll for take-off is relatively short, and the initial angle of climb is steep.
Throughout the entire speed range the airplane is statically and dynamically stable longitudinally. Lateral stability is neutral and the airplane is both statically and dynamically stable directionally. The airplane has a slight tendency to hunt longitudinally and this condition is aggravated by rough air. These qualitative tests were made with c. g. location at 26.3% MAC.
D. Trim and Balance
The airplane has trim tabs on all control surfaces and may be trimmed satisfactorily for all flight conditions except high power climbs. Any variation in airspeed and power requires a change in trim. Any nose heaviness, from extended landed gear, open coolant shutter, or external wing flaps, may be easily corrected for by use of the elevator trim control.
The airplane has good control characteristics and coordination is easy throughout the speed range. At both high and slow speeds the controls are very effective with moderate forces. Controllability throughout a stall is also very good.
The airplane is very maneuverable with excellent control during acrobatics. In both gentle and light runs, the controls are light and very effective. When pulled in moderately in a turn, it gives warning of the approaching stall by a slight buffeting and vibration of the controls.
The rate of roll of the airplane is especially good with moderate control forces..
G. Stalling Characteristics
The airplane has very good stalling characteristics in the clean configuration, power off. The stall is straight forward and is proceeded slightly by mild buffeting and stick vibration. The nature of the stall is relatively mild, with effective control throughout. No accelerated stalls were attempted.
H. Spinning Characteristics
I. Diving Characteristics
At relatively high speeds the controls are very effective with moderate forces. At extremely high speeds a distinct rumble is heard which probably develops around the coolant shutter. Considerable rudder trim is necessary for changes in speeds during the dive.
J. Single Engine Operation
Not applicable to this airplane
K. High Altitude Trials
The stability does not appear to change at high altitude, and the surface controls operated satisfactorily. Elevator trim freezes above 30000 feet and the aileron and rudder trim tabs freeze above 25,000 feet.
The cabin heater was disconnected during the tests because of fumes given off when it was in use. The cabin temperature was satisfactory up to 30000 feet without the heater, but above this altitude the cockpit becomes increasingly colder and a heater is needed for comfort.
The entire canopy frosts over when descending from altitude but as neither the defroster nor cockpit heater were operative, they could not be evaluated.
L. Approach and Landings
Landing characteristics of this airplane are very good. There is very little floating tendency and on normal landings the rudder and elevator are effective throughout. The landing flaps operate very quickly and should be handled carefully on the approach. There is noticeable nose heaviness when gear and flaps are lowered, accentuated by opening of the radiator scoop, but this is readily trimmed out with the elevator trim tab.
M. Night Flights
N. Noise and Vibration
The noise level is slightly lower because of the tight fitting canopy. Vibrations develop when running at high powers and this condition may be due to the water injection system operating improperly. The propeller also starts a noise cycle which sounds much like two propellers being out of synchronization. Though noticeable, the noise is not loud enough to be objectionable.
O. Vision and Cockpit Layout
Visibility, in general, is very good, excepting slight distortion noted in the side panels and in the rear of the canopy.
Objections to the cockpit are few. The idle cut off should be placed where it can be more easily reached. Its present location requires considerable reaching and is quite awkward to operate. The oxygen regulator should be relocated where the pilot can watch its operation, and be able to select the desired amount of oxygen with more ease. Its present location requires considerable twisting in order to read its settings which wearing an oxygen mask.
Cockpit ventilation on warm days is inadequate.
V. Shipboard Tests
A. No ship board tests performed.
VI. Performance Data
A. Airspeed, Altimeter, and Free Air Temperature Calibration
1. The airspeed, altimeter, and free air temperature position corrections are shown in Figure 1, Figure 2, and Figure 3 respectively. The location of the flush static holes and pitot head will be shown in the addendum to this report.
B. High Speed
1. Curves of speed vs altitude are given in
Figure 4 and Figure 5 at a take-off gross weight of 9484 pounds.
2. High speeds in level flight at 3000 RPM (“dry”, war emergency power) mixture auto-rich, coolant scoop in automatic, at a gross weight at take-off of 9484 pounds are presented in the following table: