LIGHT PLANE TYPES
The American Aeronca. An Intere,sting Low-Powered Single-Seater.
WITH the advent of the medium-powered twoseater machine, the small-engined ultralight, single-seater aeroplane, of which so much was expected at the time of its inception in 1923, fell out of favour in this country. The reason for this is not far to seek ; at the time of its introduction, in an experimental form, the number of people likely to require the ” pip-squeak” machine was limited to a few who were already able to fly, and the fact that it was a single-seater obviously precluded any instruction being given on it to others who were not pilots. The small demand, therefore, did not justify its development and production on commercial lines. So English manufacturers concentrated on the more practical twoseater type which has led up to the 100 h.p. high performance, go-anywhere craft which we know so well to-day, and which is rather misnamed “light aeroplane.” In America, however, the latter type of machine by no means holds the monopoly of popular favour in the private flying movement. Single-seaters of low-engine power are made and used in not insignificant numbers, and since some firms have been marketing them for some years now, it appears that in the U.S.A. there must be a definite market for them. One machine of note
is the little Aeronca, a monoplane of 26 h.p. This is made by the Aeronautical Corporation of America, and a” sample” machine is now in this country, having been acquired by Lieut.-Colonel M. 0. Darby, of the A.D.C. concern.
Both airframe and engine are made by the same firm, and throughout the whole machine considerable ingenuity has been displayed to make it simple, yet practical. The most interesting feature of the Aeronca is the fuselage. This is of welded steel tube, and is triangular in section. One longeron runs along the top to form the backbone which carries the tail unit, and to which are attached the roots of the main planes. The whole is devoid of any wire bracing, and the design appeals to one as being easy and cheap to make in quantities. The main planes are of orthodox construction, comprising spruce box spars, with spruce compression and form ribs with wire cross bracing ; as with the fuselage, the covering is of fabric. The ailerons differ from usual practice in being of metal, the covering being of light gauge aluminium sheet. The wing root attachment is of simple pattern, consisting of a sheet metal fitting which registers with a lug on the top longeron. Substantial bolts, suitably pinned, secure the whole, while
THE AMERICAN AERONCA—continuued.
flying loads are taken by four streamline wires, and landing wires brace the wings to a simple ” V ” cabane placed above.
The empennage is made on normal lines, being a metal framework covered with fabric. The fin and tailplane are braced witIltRafwires. All controlling surfaces are operated by cables.
The cockpit is placed immediately below the wings, and owing to the triangular section of the fuselage and the low sides, the view is surprisingly good. This is increased by a window set in the planes at their roots.
The undercarriage of the Aeronca is of the simplest possible design. All landing shocks are taken by the two Goodyear airwheels, and there is no other medium of absorption whatever. The wheels run on spindles which are anchored to three simple steel tubes, bolted to the forward part of the fuselage, just in front of the cockpit.
Turning to the engine, one finds, as elsewhere in the machine, that simplicity is the keynote. Of the horizontally opposed two-cylinder type, it has side-by-side valves and detachable aluminium heads. The plugs area placed in the head in such a position as to be subjected to the maximum amount of air flow. A ribbed sump in the crankcase base carries 3 gallons of oil. A noticeable point of the power unit is the manner in which the crankcase is made to give a streamline form which blends into the fairing. The petrol tank (carrying 8 gallons of fuel) is positioned just behind the engine ; feed to the carburetter is by gravity.
The makers state that the power output is 26 h.p. at 2,500 r.p.m.
Once in the air the motor can be throttled down to 2,000 r.p.m., at which speed the machine will cruise comfortably without loss of height.
In the air the machine handles in a quite normal way, and has a top speed of approximately 80 m.p.h., and a cruising speed of 60 m.p.h. It lands at 27 m.p.h. According to Mr. A. S. Thorn, who is at the present time demonstrating the Aeronca, the take off run is about 75 feet, and its rate of climb 700 feet per minute. Its range under normal conditions amounts to 240 miles.
It is understood that the Aeronca may possibly be marketed in this country in the near future (after it has been passed by the Air Ministry), and that its price will be low.
There is certainly a market now awaiting a machine of this type, which would provide an opportunity for a large number of qualified pilots to put in flying time at low cost. Moreover, although many people demand a machine of high performance with which aerobatics and long-distance flights may be carried out, there are plenty of others who wish to indulge only in sedate aviation, and who would welcome the return of the lowpowered craft for this purpose.
The specification is as follows :—Span, 36 feet ; chord, 4ft. 2ins. ; overall length, 20ft. ; height, 7ft. Gins. ; area orawings, 142 square feet ; weight (empty), 398 lbs. ; useful load, 274 lbs. ; wing loading, 4.73 lbs. per square foot ; power loading, 25.8 lbs. per h.p.