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Oddities in Recent Aircraft Design

THAT aircraft designers have not been resting on their laurels of late is amply proved by the accompanying illustrations, showing new and ingenious ideas in aircraft design as exemplified by certain leading French and German types.
Letort Let7 AirplaneLetort #7 Airplane: Crew: Three Length: 11.06 m (36 ft 3 in) Wingspan: 18.05 m (59 ft 3 in) Height: 3.70 m (12 ft 2 in) Wing area: 62.3 m2 (670 ft2) Empty weight: 1,660 kg (3,650 lb) Gross weight: 2,450 kg (5,390 lb) Powerplant: 2 × Lorraine-DietrSalmson AirplaneFokker AirplaneCaudron Airplane
These photographs have been selected from a collection of some fifty or more photographs, depicting nothing short of marvelous development in French airplanes. And no doubt the same holds true of British, Italian, German, and other planes which are engaged in the war of the skies at the present time.

The first photograph of the accompanying collection shows how stream-lining has been carried to the extreme in the latest Letort plane. The engine housing or nacelle for the V-type stationary engine on either side terminates in the fantastic prow-like end as shown, while the cylinder housings and the engine exhaust both end in stream-lined tapers. The majority of the guy wires are en-closed in stream-lined casings, and even exposed pipes, joints, and other members are stream-lined. The rear gunner, it will be noted, is located in a cockpit clear of the upper plane which is cut away at the center.

In this manner he is enabled to bring his machine gun to bear on targets at the rear, over the sides, and overhead, alone or in conjunction with the machine-gunner sitting in the front cockpit.
The second photograph is a front view of the Letort biplane; which, aside from its fantastic stream-line engine nacelles, has several novel features. In the first place, it is a three-seater twin-engined machine intended for photographic and reconnaissance missions. Its planes are back-staggered; that is to say, the upper plane is farther back than the lower one, and the struts rise backward instead of forward or perpendicularly.

A circular form of radiator is employed on this No. 7 model of the Letort type, between the cylinder casings of the engine nacelle. The forward cockpit is occupied by an observer, who operates the Lewis gun when necessary, as well as a camera which is aimed through a well in the forward end of the nacelle. Behind the observer is the pilot, and still farther behind comes the rear gunner.
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It is only when the linen covering is re-moved from the airplane fuselage that one realizes how much equipment is carried by present-day fighting machines. In the third photograph, for instance, is one of the Salmson two-seater reconnaissance and artillery-spotting machines of the French which are now beginning to appear at the front in large numbers with the French and the American forces. This view shows the fuselage with its full equipment, prior to being covered. The radial 250-horse-power Salmson engine, control stick, belt tube for the forward machine gun, screen-protected fuel tanks, extensive wiring, wireless generator, and so on appear in this view. Attention is also I directed to the delicate framing of the fuselage, each member of which is in itself far from strong, yet when combined with the others it goes to make a rigid and remarkably strong structure.
The fourth photograph is of the present Fokker scout, the latest creation of Herr Fokker, the Dutch aircraft engineer residing in Germany. This single-seater' biplane is the successor to the treacherous but speedy Fokker triplane which was being employed in fair numbers but a few months ago, and which was the mount of Baron Von Richthoffen on his last and fatal flight. The bracing of this latest Fokker is odd and interesting, since it eliminates practically all guy wires. Another feature is the small plane just below the forward body and between the wheels, which must furnish some lifting effort and thus brings this machine almost, if not quite, in the class of triplanes. In this machine Fokker has abandoned rotary engines in favor of the stationary, six-cylinder Mercedes, with the V-shaped radiator.
The fifth photograph depicts a Caudron twin-engined bomber or reconnaissance plane, which, although modified considerably, can still be traced back to the Caudrons of the early days of aerial fighting. It appears that the engines in this instance are the eight-cylinder, 300 hors-power Hispano-Suiza, a large number of which are being turned out in France both for speedy work and for the larger, multiple-engined machines. The V-shape of the engine is taken advantage of as far as possible; the engine cover in each case is of triangular section, and the struts are arranged in V-form to offer support to the engine. Some of the more important guy wires are enclosed in stream-lined covers to reduce wind resistance.

Note: French spelling for the Letort is Letord

Scientific American 1918, Volume CXIX Number 12, September 21