Although Anthony Fokker toyed with the idea in 1934 no authorities quite know where the twin-engine interceptor originated. But this military hybrid has written a history during the first three war years that makes any earlier history unimportant. Actually, the twin-engine fighter came into military being only after the undersized Bristol Blenheim, nominally a bomber, served admirably as a defensive weapon during the abortive British campaign in Norway.
Of the planes actually designed as twin-engine fighters before the war, the Focke-Wulf 187 garnered the most publicity and almost as much official German favor as the Messerschmitt's souped-up racing plane. Appropriately named Zerstörer, or destroyer, it has a top speed at sea level of 360 mph and an initial rate of climb only slightly under a mile a minute. More important, it carries a sizable arsenal along into the upper skies, with six machine guns or four machine guns and two shell-firing cannon mounted in the fuselage nose. Powered by either Mercedes-Benz 601 liquid-cooled engine developing takeoff output of 1,150 hp, or Junkers Jumo Diesel developing 1,050 hp, the Fw-187 has a ceiling of 38,500 feet altitudes at which our bombers have been operating so effectively. Any failing that the Zerstörer may have can be found in its apparent good qualities. Its terrific speed combines with obviously heavy weight to make it a poor match for skidding Spitfires which have challenged it repeatedly over England. Germany has solved that problem neatly during recent months by sending the Focke-Wulf 187 to the Russian front as an aid to the rapidly fading Heinkel 113 and Messerschmitt 109. From a spotter's standpoint, the Fw-187 is genuinely interesting because of its apparent similarity to the RAF's Westland Whirlwind. Wing is low cantilever type with straight leading edge, marked taper on trailing edge, squared wing tips. Engines are encased in surprisingly compact liquid-cooled nacelles which are square on the bottom. Mounted beneath the low wing, they descend little further than the thickness of the wing. Extremely long and flat, the nacelles extend further forward than the fuselage nose, simplifying recognition from either side or plan views. Fuselage is long, thin, and low when viewed head-on, with cockpit well forward of wing leading edge. Tail unit, though not distinctive in itself, supplies main point for distinction between the Whirlwind and the Zerstörer. Single tail has high, triangular fin, narrow triangular rudder with very little taper. Tailplane has marked sweepback, very little taper, and is mounted on the fuselage far forward of the fin and rudder.
In contrast to the much-publicized, little used Zerstörer, the Westland Whirlwind spent its entire life in the dark. Actually introduced in 1938, it served on several fronts but was not revealed publicly in this country until early this year just before all production of the type was suspended. Used on night interception, the Whirlwind has been effective against bombers because of knock-out firepower packed into the fuselage nose, but its lack of maneuverability in a dogfight made it a complete bust in daylight operations. In power plant and size, the Whirlwind is not quite so big as the Focke-Wulf, which may explain its longer survival in competition with more maneuverable types used on the European front. It is powered by two 885 hp Rolls-Royce Peregrine engines which, according to enemy sources, develop total speed of 353 mph at 16,400 feet. The Westland has a wing span of 45', is 31' 6" long, and measures 11' 7" in height. Its greatest tactical value is packed into the fuselage nose in the form of four Oerlikon 20-mm cannon. American designers find the Whirlwind interesting because of the incorporation of Fowler-type flaps into the low wing.
Spotters, on the other hand, find it appealing because identification can be confined to the last part of the usual WEFT system. The horizontal tailplane is mounted almost at the top of the wedge-shaped fin and rudder forming an easily recognized cruciform. The low wing can also be spotted with little difficulty because of its straight center section extending well beyond the nacelles, sharp taper on the trailing edge, slight sweep-back on leading edge. Engines are encased in extremely long nacelles which extend well aft of the wing trailing edge. In some views, the twin radiators, buried between fuselage and nacelles, can also be seen. The fuselage is almost a perfect match for that of the Focke-Wulf, except for the prominence of the Whirlwind's nose-mounted cannon.
Last to join the twin-engine interceptor parade, America has actually produced two planes in this class which will out-fly, out-fight, outmaneuver anything of this type ever sent into the air. Already in service over Australia and Alaska and in several other vital sectors, the Lockheed P-38 has more than won its designation as Lightning. Actual performance figures cannot be published but the P-38 is at least fifty miles per hour faster than the two previously-mentioned planes. Built specifically for sub-stratosphere operations, the Lightning climbs at slightly less than a mile a minute with more diversified armament than any plane in its class. It has a wing span of 52', is 37' 10" long, measures 9' 10" in height. It is powered by two 1,150-hp Allison liquid-cooled engines and is equipped with exhaust-driven turbosupercharger.
The Lightning will, of course, give more trouble to German pilots than to German plane spotters, The low wing tapers almost equally on leading and trailing edges and has sharply-rounded tips, Engines are encased in perfectly streamlined nacelles which continue all the way to the tail as slender booms. Prominent air scoops on both sides of each tail boom are visible in both plan and profile views. The fuselage extends slightly forward from the nacelles but terminates at the wing trailing edge. The tail is twin type with inset, egg-shape fins and rudders. Horizontal tail-plane has straight leading and trailing edges with perfectly rounded tips.
Still experimental, and reportedly modified considerably after extensive tests by the Navy, the Grumman Skyrocket ranks as America's dark-horse in the war race to produce superior fighting craft. No performance details are available but the Skyrocket has exceeded 400 mph in some tests. Structurally, it resembles nothing ever before produced in this country, and its potential tactical assignments may be equally unorthodox. It can, first of all, be distinguished from all other twin-engine fighter types by its radial engines, mounted beneath the low wing which can be spotted by typical Grumman square tips and generally straight leading and trailing edges. The fuselage begins at the trailing edge of the wing and is extremely thick and short. The twin fins and rudders can be spotted by perfect hexagonal shape and the tailplane by marked dihedral and straight leading and trailing edges. Although not yet accepted by the Army or Navy, the Skyrocket is officially designated as the XF5F-1.
There are, of course, many other twin-engine fighters on the flying line and on the drawing board, with the Bristol Beaufighter, in its two versions pictured elsewhere in this issue, still ranking with the best. Germany has the relatively ancient Messerschmitt 110 and its successor, the Messerschmitt 210. The former has a speed of about 340 mph and a ceiling of 32,000 feet, and the latter develops considerably greater top speed with Daimler-Benz 601N engines. Britain, of course, has more than one plane of this type on the secret list. Three of these in particular so far outclass everything but the P-38 that Germany's 210 hardly rates consideration.
This article was originally published in the December, 1942, "Complete Spotter's Guide" issue of Air News magazine, vol 3, no 6, pp 38-39, 98.
Air News was published on newsprint in 10½" × 13½" format.
The original article includes 4 photos: FW-187, XF5F, P-38, Whirlwind.
Photos credited to European, Rudy Arnold, Press Association.