Combat Cousins of the Jap Zero

Some of the same experts who, during the Battle of France termed our lend-lease lighters winged coffins, referred to their air-cooled engines as built-in headwinds and wept bitterly at their lack of armor, dreadnaught gun-power and self-sealing tanks, are now asking just as loudly for a plane with precisely these characteristics — specifically, a plane that will outclimb, and turn inside of, the Jap Zero.

Fortunately for our national sanity, a specimen of the main subject of this journalistic tirade, the Mitsubishi Zero, is now in our possession. Having taken off from a carrier somewhere off the Aleutians, the ship was apparently forced inland by US fighters, where it ran out of gas. What the pilot, unfamiliar with the Alaskan terrain, supposed to be a smooth landing surface below turned out to be muskeg, a combination of brush moss and mud. Five days later the pilot was found, his neck broken, but the Zero was still in one piece, having suffered only a bent prop and other superficial damage.

The ship was crated and sent to the Navy's North Island station near San Diego, where it was quickly repaired and made ready for flight tests. While complete official specifications have not been released as yet, there are enough available data to indicate that the Zero is no aero-miracle. A formidable adversary, it is far from the type of airplane in which we would like to send our men to battle. In the words of Under-Secretary of War Patterson, "The Zero would not be tolerated in the US Army Air Forces." This appraisal is graphically substantiated by the Pacific air war box score. The Nipponese have lost five men for each American fatality and three ships to our one. Many of our own pilots have been able to land crippled fighters and walk or float away. Zeros shatter to bits when hit or forced to land on rough terrain.

The Zero is outweighed some 1,700 pounds maximum on takeoff with chief naval opponent, and there is a difference of approximately a full ton between it and the standard Army types. This disparity is chiefly accounted for by guns, armor, self-sealing tanks and devices for easy maintenance and pilot safety.

The Zero weighs less than 5,100 pounds maximum on takeoff with its disposable wood and fabric tank, lacks any of the US ship's safety devices and has applied every structural trick in the book to spare weight and lighten the structure.

The result is a fairly fast, quick-climbing, maneuverable airplane. There is a rumor to the effect that the Zero is a copy of several export US aircraft. Several features of the engine and airplane have been directly borrowed, but for the most part it is a home-grown product.

The Japanese high command, having seen their natural resources dwindle from the protracted war in China, knew that, for the quick victory which was vital to the continuance of their imperialistic policy, they had to achieve a series of stunning air blows. They watched the lessons of Europe's war add armor, guns, built-in rafts, etc, to US airplane designs. The obvious weakness was this increase of wing loading, the great weight that every square foot of wing had to carry.

In a turn, centrifugal force increases the weight of an airplane. The tighter the turn, the more the airplane weighs. There is a limit to how much weight the wing will sustain; as a result the airplane with the lighter wing-loading has a greater differential between its actual weight and the maximum the wing can sustain. Hence, the lighter airplane can make the tighter turn at the same speed.

This tighter turn has one advantage in a dogfight. The ship with the inside track on a turn has a longer opportunity for deflection shooting. This term, roughly, indicates a side-long burst of fire at an enemy, fired at a leading angle from the banked position, This is generally the equivalent of leading a bird in wing shooting.

The two-fifths loss differential indicates the great price that Japan is paying for the privilege of a tight turn and higher rate of climb. That the price is too high and that some of the newer Jap types have fallen below the Zero's general performance level may be caused by the addition of some safety measures.

Outzeroed — in 1917 and 1938

As early as five years ago, ships were produced in this country that were capable of outperforming the current Mitsubishi on many points. Among these were the Curtiss-Wright 21 interceptor, the Hawk P-75A and, in some phases, the Vought-Sikorsky V-143. Like the current Zero, they too were lightly armed and lacked such devices for the promotion of pilot longevity as armor and self-sealing tanks. Still, their performance stacked up at least decently against the Zero we know today and flew rings around contemporary Jap ships.

The nations have chosen their philosophies of battle and design. If the Japanese change theirs, they have to go back to their last point of design departure and catch up to us. The following set of figures indicates some interesting facts about the comparative efficacy of the designs. These figures are fair comparisons, as the Japanese for the most part used radial air-cooled engines just as we do, and for the most part followed the same structural procedures.

The first set of comparisons is between the Standard Jap fighter in current use and two. US types built four and five years ago respectively: If we had chosen to continue along these lines for the period between, we would probably have caught up and surpassed the opposition. Further evidence of this can be secured by comparing performance data between the last of our lightweights and its Japanese contemporary. The old Curtiss Hawk 75, the last fixed landing gear fighter, could have been considered a contemporary of the Mitsubishi 96 that made itself such a nasty reputation in China. The 75 was followed by the 75A, which the US Army put into service as the P-36. This same type was exported to England and France under lend-lease and was discovered to have the basic weakness of being too light. The French pilots pulled the same tactics on the Messerschmitts that the Japanese are trying on our ships. Results, so far, are about parallel.

Plane:Mitsubishi 00C-W 21V-S 143
Engine:Kinsei
1,000 hp
Wright Cyclone  
1,000 hp
P&W Wasp Jr
750 hp
Span:35 feet35 feet33' 6"
Length:27 feet27 feet26 feet
Armament:two 7.7 mg
two 20 mm cannon  
two .30-cal mg
two .50-cal mg
two .30-cal mg
two .50-cal mg
Speed:315 mph310 mph320 mph
Climb:4,000 ft/min5,200 ft/min3,000 ft/min
Range:600 miles600 miles950 miles
Turning Circle:  440 yards440 yards500 yards
Wing Loading:24-25 lbs/sq ft25.2 lbs/sq ft23.4 lbs/sq ft
Weight:4,750 lbs
(fighting weight)
4,300 lbs4,350 lbs

The following tables compare the performance of the four ships: The new types that face the opposition in the East are, for the most part, more powerful ships. An interesting note is their increased wing area in proportion to their size. This indicates that the weight held necessary for pilot security has not been pared. Rather, it has been taken into account and the basic design has been laid around this 2,000 additional pounds of weight.

We were plainly able to outperform the opposition five years ago. If they, in turn, fail to even the box score, despite their sacrifice of safety for performance, our basic national philosophy for combat is surely indicated to be panning out better. All other things being even, the ultimate result, while it may be some distance away, is reasonably plain.

Plane:Mitsubishi 96  Mitsubishi 97  Curtiss Hawk 75
(Fixed gear)
Curtiss 75A
(P-36)
Engine:Kinsei
750 hp
Kinsei
850 hp
Wright Cyclone
840 hp
Wright Cyclone
900 hp
Span:36 feet40 feet37' 3.5"37' 3.5"
Length:24' 6"25 feet28' 7" 28' 7"
Height:9' 4"9' 2"9' 3"9' 3"
Weight:4,300 lbs4,500 lbs5,700 lbs5,690 lbs
Armament:two 7.7 mgtwo 7.7 mgone 50-cal,
one 30-cal mg
and 550 lbs of bombs  
or 2 more .30-cal mg
one 50-cal,
one 30-cal mg
and 550 lbs of bombs
or 2 more .30-cal mg
Speed:250 mph265 mph280 mph303 mph
Climb:2,300 ft/min2,800 ft/min2,340 ft/min2,600 ft/min
Range:440 miles 974 miles1,380 miles1,040 miles
Turning Circle:  460 yards500 yards480 yards550 yards
Wing Loading:20 lbs23 lbs22.5 lbs24.1 lbs

This article was originally published in the January, 1943, issue of Air News magazine, vol 2, no 1, pp 56-57, 72.
The original article includes 4 photos.
Photos credited to British Combine, Hill & Knowlton, Vought-Sikorsky, Curtiss-Wright.