Flight, February 12, 1915.
THE EVOLUTION OF THE ETRICH "TAUBE."
Another machine, (c) Fig. 4, was a totally enclosed military monoplane built in 1912. The wings were of orthodox Etrich form, cable braced top and bottom, having a span of 12 m. The fish-shaped body was built up of wooden channel-section longitudinals, and wooden rings, covered with sheet aluminium from the nose to just behind the wings, and with fabric for the remainder. The wings were attached to the body high up, and the sides of the body underneath were cut so as to form windows. Inside the body were four seats, two pairs in tandem, the pilot being at the rear. The windows were of wire gauze and celluloid. A 60 h.p. Austro-Daimler engine was mounted high up in the nose of the body. The undercarriage consisted of a tubular axle and pair of wheels connected to the body by four tubular steel struts. Later this machine was altered, the seats were placed higher up, so that the pilot and passenger protruded above the body, whilst an additional wheel was mounted under the nose. Neither of these two machines showed to any particular advantage, and did not, therefore, form an important part of the Etrich programme.
Flight, April 26, 1917.
THE "TOTALLY ENCLOSED" AEROPLANE.
During the spring and summer of 1912 the Austrian Etrich firm built and experimented with an enclosed monoplane of the Taube type. As our illustration shows, this machine was very similar in general arrangement to the ordinary Etrich taube, with the exception that the body had been made considerably more roomy. Constructionally the body was of the girder type with a superstructure giving the covering an elliptical form in section. Windows of non-inflammable material were provided in the sides and nose, and as the engine was mounted very high up in the body, the view forward and downward was exceptionally free, considering that the machine was of the tractor type. The two seats were placed one behind the other, and the pilot occupied the rear one. Apart from the fact of it being enclosed, this monoplane was a departure from standard practice in other respects. For instance, the under-carriage was of the simple Vee type that is so popular on modern machines, but which had not become generally adopted at that time. The wings, which had the usual back swept and upturned tips characteristic of the taube, were attached to the body by a single tubular pivot, and provisions had been made for varying the angle of incidence during flight. This was accomplished by rotating a wheel mounted in the body to the right of the pilot.
For some reason no more machines of this type were built by the Etrich firm, whether this is due to the enclosed feature or to other causes. Probably the reason was that, like so many others, this new departure had too many unknown factors. On the face of it, it would appear that the centre of thrust was too high, being approximately in line with the intersection of the chord line and the resultant, while the centre of resistance of the body and that of the under-carriage were some distance below this point.