Kawanishi N1K George performance

[alejandro_]

I am looking for a speed-altitude diagram and climb rate chart of this aircraft. I have tried several websites and manuals (TAIC) but I have found nothing. Does anyone know where I could find this information?

Thanks.

 

[alejandro_]

I found some data in an article in Air Enthusiast (April 1973):

N1K1-J:
334mph at 9.842ft
363mph at 17.716ft
355mph at 18.373ft

N1K2-J:
359mph at 9842ft
369mph at 18373ft

 

[alejandro_]

During the final months of WWII, an allied test pilot was given the task of performing the initial evaluation flight of an N1K1-J Shiden found intact in the Philippines by advancing Allied forces. The aircraft was flown with the fuselage and underwing guns removed, and was in excellent mechanical condition apart from the brakes, the starboard brake being virtually ineffective. The primary purpose of the flight was to check out the airraft preparatory to full tactical trials, but at the end of the landing roll the starboard oleo leg collapsed and the Shiden was so badly damaged that it could not be flown again. The test pilot's report follows.

The N1K1-J possessed excellent take-off, climb and high speed characteristics, and afforded good vision from the cockpit, but from the pilot's viewpoint was inferior to the J2M3 Raiden, not impressing one with that feeling of confidence normally associated with a good, substantial aircraft. The cockpit layout was, in general, very good with the flight instruments well grouped. The airspeed, rpm and manifold pressure gauges were mounted high on the instrument panel and easily read during the take-off run. All cranks and controls were readily to hand and easily operated with the exception of the undercarriage and flap controls.

This fighter was fairly comfortable for a pilot of normal stature, but an objectionable feature was the rigging of the stick which was both too high and too far forward for comfort. The aircraft appeared well ventilated, although this may have been due to the removal of the fuselage guns, there being no ventilating system installed in this particular aircraft. The rudder bar was very narrow and the operation of the brakes difficult with full rudder. The narrow cockpit canopy did not allow much movement of the head, but the cockpit, being mounted high in the fuselage, provided good vision over the nose, vision for taxying being particularly good for a tailwheel-equipped fighter and better than that for either the J2M3 or Ki-84. All round vision could be considered excellent.

The N1K1-J was flown from a macadam runway and taxying and ground handling in general proved poor owing to the ineffective brakes. The rudder was of little help for taxying but this was improved with the flaps extended due to the fact that the throw of the rudder was increased from 23 deg to 33 deg with flaps down. If the power was applied gradually take-off was normal with little tendency to swing, but the aircraft was tail heavy and the tail did not come up very readily. The take-off run was short and the aircraft left the ground easily at about 105 mph, the undercarriage retracting slowly with little change in trim.

The initial climb was excellent. At 2350 rpm and indicated speed of 140 mph the stabilized rate of climb indicated approximately 2200 ft/min at 8000 ft. The aircraft was then tested from the stall up to 360 mph indicated, and the rudder proved light and effective at all speeds while the ailerons were found to be effective but slightly on the heavy side at all speeds up to about 320 mph. The rate of roll was good up to 360 mph at which the ailerons became extremely heavy. The controls were unbalanced in that the rudder and elevators were much lighter than the ailerons and could be considered as too light. The rudder and elevators were fitted with trim tabs for which the controls were positioned on the port side of the cockpit. These controls were excellent. There were considerable changes in rudder trim with speed and power.

The stability of the N1K1-J at cruising speed was excellent. This was checked at 7000 ft with 2100 rpm, oil and cowl flaps closed and an airspeed of 189 mph indicated. Directionally and longitudinally it was statically and dynamically stable and laterally was just about neutrally stable. The aircraft was stalled both clean and dirty and revealed a serious port wing stall under all conditions, the stall coming without any warning other than when the cowl flaps were open, the stall then being preceded by vibration. The N1K1-J was stalled clean at 100 mph, with cowl flaps open 20 deg at 104 mph, with undercarriage down at 100 mph and with both undercarriage and flaps down at 85 mph.

As this particular N1K1-J had apparently previously been crashed and rebuilt, and the repairs were of unknown quality, no rough manoeuvers were attempted, but it appeared that the aircraft could easily be damaged as a result of rough handling of the overly light elevators. It performed a snap 1/3 port roll at 125 mph in a 2G turn to port or starboard, it executed rolls and Immelmans rather sloppily but turned well as a result of its good rate of roll and light elevators.

On the approach the undercarriage and flap handle had to be returned to neutral or else there was no brake pressure, and there was too much change in trim as the flaps were lowered and speed was lost, but in other respects the approach was very straightforward with excellent vision for the pilot. The aircraft was easy to land with all oleos being soft and the tail came down readily, but the one landing was made crosswind and while the N1K1-J was stable in the landing run, it was obvious that it should not be operated from prepared runways owing to its poor brakes.

The Homare power plant appeared to be generally very satisfactory, easily starting up from cold but loading up when hot. It was found to run smoothly at all rev settings. The mixture control was similar to that found on the North American T-6 with positive lock fitted, and the airscrew operation was hooked in to the throttle and functioned very well, this automatic airscrew-throttle arrangement undoubtedly being advantageous in combat. Engine cooling was not good, cowl flaps having to be opened up fairly wide in normal climb, and cylinder head temperatures were very dependent on cowl flap openings.

The flight lasted for 1 hr 45 min, and the conclusions were that the N1K1-J had the following favourable features: good vision, good stability, good take-off qualities; good performance; a high diving speed and a good instrument layout. Its unfavourable features were: poor stalling and accelerated stalling characteristics; ineffective brakes and rudder brake action; weak undercarriage; complex gear and flap system; poorly balanced controls and heavy ailerons at high speed.

Air Enthusiast, April 1973.

 

[msxyz]

Is there a similar evaluation report done for the N1K2?

Quite a few Shinden Kai were captured (at least 3 are preserved in US museums alone) and I seem to remember that one was also flown in a few air shows till the early '60s. I'm curious if moving the wings down the fuselage did improve the flight and stall characteristics, among the other things. The Shindens used laminar flow wings which give much less warning when they're about to stall but this alone says little of the stall behavior. Planes like the P51 and the J2M also used laminar flow wings and had no adverse stall behavior.

As for performance data, Mick Spick, in the "Illustrated directory of fighters", reports that a captured Shiden-kai reached 670km/h (416mph) at an altitude of 5,800m. This figure is consistent with similar data from post war evaluations of several captured japanese fighters using the troubled Homare engine. When properly maintained and with the 100+ octane fuel needed to sustain high manifold pressures, the Homare could be used to its fullest potential (1800-2000 HP depending on model).

 

[Laurelix]

N1K2-J Prototype with Derated Ha-45-21 engine test flght results:
3800kg loaded
611km/h at 6000m at military power
6:20 to 6000m at military power

Production version with proper fixed if issues Ha-45-21 (1990hp take off, 1825hp at 1750m, 1625hp at 6100m)
3800kg loaded
635km/h at 60000m at military power , 658km/h at War Energency Power
5:37 to 6000m at military power