Flight, April 1926

THE AVRO "GOSPORT”
A New Training Machine of "504" Type

   PERHAPS one of the most remarkable features in the development of aeroplane design is centred around the world-famous Avro "504" biplane - which is a sort of "Peter Pan" of the aeroplane world. After Mr. A. V. Roe had produced his triplanes, during 1909-1910, he designed in 1911 a tractor fuselage biplane - one of the first aeroplanes of this type in the world to be produced - which was developed into the original "504" in 1913. Since that time this type has been multiplied to the umpteenth power, yet, although vastly improved aerodynamically, outwardly this aerial Peter has not appreciably grown up! This may be appreciated by comparing the accompanying illustration of the original "504" - which startled the aviation world in the summer of 1913 at Brooklands and Hendon - with the companion picture of the latest development of this type (the 504 R. "Gosport"), which we are able to describe this week.
   It is the opinion of the house of Avro that the "light aeroplane" is unsuitable for the serious training of pilots. They have, therefore, designed this new type 504G., which, while being lighter in construction than other Avro training machines, is yet sufficiently strong to withstand the rough handling to which a training machine is subject. This machine is the outcome of their long and unparalleled experience in the production of training aircraft, and every quality essential for training purposes is incorporated in the design.
   The fuselage is similar in construction to that of all Avro training machines, and is in the form of a wire-braced girder. This method has been proved in practice to be very strong, and at the same time to provide the best facilities for repairs in case of damage.
   The instructor and pupil (or pilot and passenger) occupy two cockpits, which are arranged in tandem, and all machine and engine controls are duplicated in each cockpit. A particular feature, and one which is essential in a practical training machine, is that the machine can be flown equally well, and landed with equal safety, from either cockpit. If desired, special seats can be fitted in order that the Irving seat-type parchute may be used.
   The main planes are built up on two spars of solid silver spruce spindled to a suitable "I" section. The ribs are of the same material, and the whole structure is cross-braced with high-tensile steel wire.
   The top main planes differ slightly from the bottom planes in that the inner portion is tapered to suit the centre-section plane, which has been cut away at both leading and trailing edges as far as the main spars. As a result of this alteration both instructor and pupil have a much better overhead view - a distinct advantage in a training school, where often several machines are in the air at the same time.
   The contour of the ailerons has been altered in such a way that they now harmonise perfectly with the elevators. All controls are particularly light, and very sensitive, and the machine responds immediately to the slightest touch.
   The fixed tail plane is in two sections, and an elevator is hinged to the trailing edge of each tail plane. Both tail-planes and elevators are interchangeable port or starboard. The rudder is of the balanced type.
   The interplane struts are of solid silver spruce carefully streamlined, with bracing ties of flexible steel cable, and the lift cables are in duplicate.
   The undercarriage is similar to that fitted to the famous Avro 504K training machine, and has been specially designed for training purposes. The shock absorbers consist of rubber cord in tension and are built to withstand very heavy landing shocks. The most important feature of this undercarriage, however, is the long main skid, which not only protects the tip of the propeller in the case of a faulty landing by a pupil, but in a similar occurrence often prevents the machine turning over on its back, with serious consequences. The tail skid is sprung by rubber pads in compression.
   The petrol and oil tanks are fitted inside the fuselage above and forward of the front seat. Petrol is pumped to the engine by means of a hand-pressure pump, which may be operated from either cockpit.
   The engine fitted is the new model 100 h.p. Monosoupape with "Y" metal pistons, which obviate the necessity for obturator rings.
   In conclusion, it should be mentioned that every part of this machine is absolutely standardised in order to ensure complete interchangeability.
   Its performance as a training machine is beyond comparison, and because robustness of construction has not been sacrificed for the sake of lightness, it is economical in operation.
   The name "Avro" has always been the hall-mark of the best training aeroplanes; the word "Gosport" at once brings to mind the most thorough and scientific system of training that has ever been devised, and which was, from the outset, operated by the earlier 504 type of Avro aeroplane. For these reasons, this, the latest training aeroplane, has been rightly named the Avro "Gosport."
   The principal characteristics of the "Gosport" are as follows
   Span 36 ft 0 in.
   Chord 4 ft 9-75 in.
   Gap 5 ft 5 in.
   Overall Length 28 ft 11 in.
   Overall Height 10 ft. 4 in.
   Area of main planes 320 sq. ft.
   ,, ailerons 40 ,,
   tail plane 26 ,,
   ,, elevators 10 ,,
   „ rudder 9 ,,
   Dihedral angle 2-5°
   Angle of incidence 4°
   Weight empty 1,107 lbs.
   Useful load 569 lbs.
   Weight laden 1,676 lbs.
   Weight per square foot 5-24 lbs.
   Weight per horse-power 15-52 lbs.
   Speed range 35-87 m.p.h.
   Climb to 10,000 ft. 24 mins.
   Service ceiling 13,000 ft.
   Duration (cruising) 2 hours.