Flight Test Engineering Branch
Memo Report No. Eng-47-1726-A
28 March 1944
HAMP, AAF NO. EB-201
Flight tests have been conducted at Wright Field on the Japanese Mitsubishi Type 0 MK2-SSF Hamp Airplane, AAF No. EB-201, at the request of the Technical Data Laboratory, Engineering Division. The tests were made in order to compare the Japanese Hamp fighter with AAF fighters and in part to verify tests made in Australia by the Special Duties and Performance Flight of T.S.-7, Directorate of Technical Services, Melbourne.
From 9 January 1944 to 10 March 1944 approximately 36 hours were flown on the airplane of which approximately 14 hours were flight test time flown by Lt. Col. H. Estes, Jr., Capt. R. C. Hoewing and Capt. C. E. Lundquist. The remaining 22 hours were mainly P? flight time, required because of the difficulty of maintenance on the airplane.
The airplane is equipped with a Nakajima Sakae 21 aircooled, 13 cylinder radial engine and a three blade, hydraulically operated, constant speed propeller with setting of 27.5° and 47.0° at the 42 inch station and using a modified Clark Y airfoil over the greater part of the blade and a low drag section at the tip.
No horsepower data is given because no correlation could be obtained between variouos sources of data on engine power output for given conditions of engine RPM and manifold pressure.
The Japanese Hamp, AAF No. EB-201, is a low wing single engine fighter of all metal, stressed skin design. The fuselage is in two sections, joined aft of the pilotís compartment, the forward section is of the semi-monocoque construction, the rear section is full monocoque. The wings are integral wit the forward section of the fuselage.
The airplane is highly maneuverable, has a fair rate of climb, and good visibility; however, its speed in level flight is low, it is lightly armed, has no armor protection for the pilot, and the fuel tanks are not self sealing. The cockpit layout is fair, leg room is insufficient for an average sized man and application of the brakes with fully extended rudder is impossible.
The principal results are as follows. All flight tests were performed at rated power and no data is available at maximum emergency power, 2600 RPM and 40" Hg. manifold pressure.
|a.||Maximum speed at low critical altitude = 9,300 ft.|
(2400 RPM and 36" Hg. man. press.) = 310 MPH
|b.||Maximum speed at high critical altitude = 15,300 ft.|
(2400 RPM and 36" Hg. man. press.) = 308 MPH
|c.||Rate of climb at sea level|
(2400 RPM and 36" Hg. man. press.) = 3260 ft/min.
|d.||Rate of climb at low critical altitude, 7000'|
(2400 RPM and 36" Hg. man. press.) = 2980 ft/min.
|e.||Rate of climb at high critical altitude, 15,000 ft.|
(2400 RPM and 36" Hg. man. press.) = 2180 ft/min.
III Condition of Aircraft Relative to Tests
A. The gross weight at take-off was 5835 lbs. with a c.g. located 0.075 inches forward of the main spar, approximately 31% M.A.C., landing gear down. Gross weight included pilot, 1?? Gallons of fuel, 52 quarts of oil, and 200 lbs. ballast for ammunition.
B. The fuselage guns were uncovered but the gun ports located in each wing were covered with a fabric patch. The radio antenna arrangement is shown in the photographs in Section X. The droppable fuselage tank was not attached during the performance flight tests and as the fittings are internal they produce no appreciable drag.
C. The armament consists of two 7.9 mm machine guns mounted on the upper fuselage and synchronized to fire through the propeller arc and a 20 mm Oerlikon cannon mounted in each wing and firing outside the propeller arc.
D. The airplane was flown with best power mixture, carburetor cold, cowl flaps flush, fuel tanks and oil cooler shutters closed, landing gear and flaps up, and cabin closed.
E. Best power mixture may be visually determined by means of an exhaust temperature gauge located in the cockpit. It was determined that a temperature of 67°C ± 20°C corresponded to best power mixture below 20,000 ft.
IV Flight Characteristics
A. Taxiing and Ground Handling - Faulty brakes and the difficulty of applying the brakes when full rudder is applied makes taxiing extremely difficult. The brake bands are said to be too small for the airplane and it is thought that if the brakes were satisfactory the taxiing and ground handling would be fair.
B. Take-off - because of faulty brakes all torque correction must be made by use of rudder; therefore must be applied slowly. The rudder becomes effective at approximately 30 MPH indicated airspeed. The take-off roll is short, initial climb is steep and visibility over the nose is good.
C. Stability - Although no stability tests were made, the airplane appears to be stable in all flight conditions.
D. Trim and Balance - The elevator trim tab is adjustable by means of a control wheel located on the left side of the cockpit. Aileron and rudder trim tabs are fixed and while change in rudder trim is not excessive, an adjustable trim tab would be desirable, especially in climbs.
E. Controllability - All controls are satisfactory from stall to 225 MPH indicated. Above this speed the control forces become heavy with the ailerons becoming extremely heavy above 250 MPH indicated airspeed.
F. Maneuverability - The Hamp is very maneuverable at indicated airspeeds of 150 to 250 MPH; above this range the aileron forces are too heavy and the rate of roll is decreased. The radius of turn is short and the zooming characteristics are good. The ship is very good for aerobatics and is superior to AAF fighters in this respect.
G. Stalling Characteristics - The stalling characteristics of this airplane are very good. The indicated stalling airspeed with power off is 72 MPH, with landing gear and flaps down abd us 76 MPH with landing gear and flaps up. With power on and the cowl flaps partially open it is impossible to obtain a complete stall.
H. Spinning Characteristics - Not performed.
I. Diving Characteristics - The airplane handles normally but its diving speed is slow, due to the extreme light weight. The control forces, particularly the aileron control forces, become excessive above an indicated airspeed of 250 MPH. Both cylinder head and oil temperatures get too low for safe operation in prolonged dives.
J. Operation of Reduced Number of Engines - Not applicable.
K. High Altitude - No cockpit heater was provided; however, no discomfort was felt even at high altitudes. The elevator trim tab and ailerons were found to freeze at high temperatures, possibly due to congealing of the lubricants at the low temperatures encountered.
L. Approach and Landings - The approach for landing was made at indicated airspeeds from 95 to 100 MPH. Vision was good and landing could easily be made in a three-point position. There was a slight ground looping tendency, usually to the left, which could easily be controlled by the rudder of brakes.
M. Night Flying - Not performed.
N. Noise and Vibration - The noise level was considered normal and no vibration was noted.
O. Pilots report on Vision and Cockpit Layout - Vision was considerably better than in AAF fighters. Visibility was fair for taxiing and good in climb, level flight and glide. Vision to the side and below and above was good, vision to the rear was satisfactory although the airplane was not equipped with a rear view mirror. The cockpit layout was fair. The flight and instrument arrangement was good. The landing gear and flap control levers were located on the right rear side of the cockpit and their operation was awkward. There was not sufficient leg room for the average pilot although the cockpit was probably sufficiently large for the average Japanese pilot. Rudder application was extremely difficult and the use of a rudder bar made it impossible to apply the brake when the rudder was fully extended. There was ample shoulder and head room even for a large pilot.
P. Crew report on Layout of Individual Stations - Single place airplane.
V Ship Board Tests Ė Not applicable
VI Performance Data (2400 RPM, 36" Hg. man. press. and at a gross weight of 5835 lbs. at take-off).
A. Airspeed and Altimeter Indicator Calibration (See Fig. 1 and 2)
Airspeed and altimeter indicator correction with pilot-static head #4586 (see fig. 1 for descriptive symbol inscribed on head) located 25 inches inboard of left wing and with static holes located 13 inches from leading edge of wing.
B. Maximum Speed (vs Altitude) (See Fig 3.)
High Speeds in level flight at 2400 RPM, cowl flaps at flush position.
* Low blower critical altitude
C. Climb Data (See Fig. 4)
Rate of climb at 2400 RPM, cowl flaps flush.