The Development of the Light 'Plane

The Development of the Light ‘Plane

G. G. 0. MANTON.

JUST over six years ago a stir was caused in the aviation world when an aeroplane was successfully flown, powered with an engine of only 400 c.c. capacity. The machine in question was known as the “Wren,” and its diminutive power unit was an ordinary A.B.C., taken from a motor cycle. Up to the time of its appearance the prevailing opinion was that no machine was safe or practical unless powered with a motor of at least 45 h.p. and consequently when the ” Wren ” not only flew, but flew wonderfully well a mild sensation resulted.

Civil flying was in a very anaemic state in, 1922-1923 and private aviation, owing to public apathy and lack of suitable machines, was practically non-existent. The advent of an aeroplane of so simple a construction as the “Wren,” which called for no very great skill or expense to keep in trim and to run, was bound to arouse considerable attention and there were few of us who have been interested or associated with aviation during the last decade who were not intrigued with the possibilities which such a machin,e offered. Thus, it was that other machines of similar type were evolved by the majorityof our leading manufacturers so that when a competition was organised in October, 1923 no less thsii, twenty-eight ” pip-squeaks ” of the air figured in the list of entries. All these planes were of the single-seater type, and, due to the rules of the competition, none was powered with an engine of more than 750 c.c. capacity. It should be mentioned that in every case motor cycle power units were adopted and considering that they were never designed for aero work, the results obtained were noteworthy. During the six days occupied by the competition, for instance, Bert Hinkler covered 1,000 miles on an Avro monoplane and had no trouble whatsoever. His engine was a 750 c.c. Douglas which drove a geared-down chain-driven propeller. There were others, of course, who were n,ot so fortunate and there were a good many “bursts,” but the Avro was not the only craft to put up a good show. A prize was oftered for the highest average speed over the 124miles course, and this was secured by the Parnall ” Pixie,” a particularly attractive little machine also fitted with a Douglas engine, and Captain, Macmillan., her pilot managed to lap at 76 m.p.h. in weather which was far from ideal. Other outstanding performances were made in respect of petrol consumption and altitude, notably by the “Wren,” which tied with a Blackburne-engin,ed A.N.E.C. monoplane in averaging 87 m.p.g., while the latter also secured the height award by a climb to 14,400 feet. Altogether the results of the contest proved conclusively that it was possible to build an aeroplane of no more than 10 h.p. which would carry its pilot quite easily and the next step was to produce a two-seater on similar lines, and in due course a n,umber

appeared in another competition held at Lympne aerodrome in the following year. In this contest it was deemed advisable to raise the stipulated engine size to a maximum of 1,100 c.c. capacity. Motor cycle engines were again in evidence, but to a lesser degree, owing to the introduction of a new fiat-twin aero engine—the Bristol “Cherub.”

The ” Cherub ” showed itself to be an exceptionally fine little motor ; it was reliable, powerful (it developed 32 h.p. at 3,200 r.p.m.), and weighed slightly over 90 lbs., and it was significant that the more important prizes were carried off by machines which were” Cherub” engined.

The principal award went to the Beardmore “Wee Bee,” a machine of the high-wing monoplane type, which with full load had a speed range of from 39 m.p.h. to 71 m.p.h. and another winner (for greatest distance covered) was the C.L.A.2 biplane. This plane was of particular interest, as it was of private construction, having been built by the staff at Cranwell R.A.F. college to the design of its pilot, Lieut Comper. It covered a distance of 762 miles and its actual flying time was 17 hours, 53 minutes. Incidentally the latter has now left the Air Force and is engaged in the manufacture of a light 2-seater monoplane bearing his name.

On the whole the 1924 competition was enlightening, but somewhat disappointing, for though the perforthances of the winning machines were good, there were a good many retirements, and the consensus of opinion was that while a reasonably efficient single-seater plane might be built with an engine of about 10 h.p., a twoseater of very little higher power could not be made to function satisfactorily.

In the meantime the De Havilland Co., had been quietly at work on the first of their now famous” Moth.” Here was a machine essentially for the private owner, for with its folding wings, which solved the housing problem, dual-control, robust 4-cylinder air-cooled 27-60 ” Cirrus ” engine it was easy to handle, cheap in upkeep and capable of serious touring work. From its inception it was a great success and, it is safe to say, that it not only set the fashion in light aeroplanes but laid the foundations of the movement as we know it to-day. Again the trend of design changed, and the ..kvro ” Avian.”, the Blackburn ” Bluebird,” the Westland Widgeon,” the Sinamonds ” Spartan ” appeared in due course as healthy rivals to the “Moth.” With each succeeding year improvements are added to these fine little machines ; the power of the engines is being raised, the cockpits made more luxurious and detail refinements added, so that to fly in them is to experience a de luxe form of travel. How quickly and to what extent their development will be made in years to come only the future can tell, but is certain that the light plane has been a potent factor in the ushering in of the air age. Nevertheless, great as one’s admiration must be for the present day light aeroplane, there remains a certain feeling of regret that its success brought about the abandonment of those little single-seaters of six years ago. A few of them, in the hands of private owners, are still going strong and there are many who envy them in possessing them, for these diminuitive craft make a definite appeal to the sportsman. However, there are indications that the single-seater low-powered sports plane will shortly make its “come-back “—the GlennyHenderson is perhaps the precursor—and it is certain that it will be welcomed.