de Havilland DH.83 Fox Moth
В 1931 году главный конструктор фирмы "de Havilland" А.Е. Хэгг разработал модель DH.83 Fox Moth для удовлетворения запросов на легкий транспортный самолет с хорошими характеристиками и низкой ценой. К стандартным компонентам Tiger Moth (бипланная коробка,
хвостовое оперение, шасси и силовая установка) он добавил новый деревянный фюзеляж с фанерной обшивкой, открытой кабиной пилота и размещенным перед ней закрытым салоном для трех пассажиров. Прототип с мотором Gipsy III мощностью 120 л. с. (90 кВт) впервые взлетел 29 января 1932 года. Позднее эту машину отправили в Канаду для испытаний на поплавках и лыжах, проведенных совместно с фирмой "Canadian Airways Ltd". Эти испытания прошли успешно, в результате чего восемь из 98 выпущенных в Британии Fox Moth экспортировались в Канаду в 1932-1935 годах. Еще два экземпляра собрали на фирме "de Havilland Aircraft of Australia".
Многие из этих самолетов были оснащены моторами Gipsy Major, некоторые имели закрытый фонарь кабины пилота. Японцы собрали один самолет со звездообразным мотором мощностью 150 л. с. (112 кВт) под именем Chidorigo. Он летал в авиакомпании "Japanese Aerial Transport Company". После Второй мировой войны фирма "de Havilland Canada" построила 52 экземпляра DH.83C с рядом изменений, включая триммеры на рулях высоты, увеличенный фонарь кабины пилота и мотор Gipsy Major 1C мощностью 145 л.с. (108 кВт). Другой экземпляр DH.83C (вариантов DH.83A или DH.83B не было) построила фирма "Leavens Bros Ltd" в 1948 году.
de Havilland DH.83 Fox Moth
Тип: легкий транспортно-пассажирский самолет с одним пилотом
Силовая установка: перевернутый рядный поршневой двигатель de Havilland Gipsy Major мощностью 130 л. с. (97 кВт)
Летные характеристики: максимальная скорость 182 км/ч на оптимальной высоте; крейсерская скорость 154 км/ч на оптимальной высоте; начальная скороподъемность 184 м/мин; практический потолок 3870 м; дальность полета 579 км
Масса: пустого самолета 499 кг; максимальная взлетная масса 939 кг
Размеры: размах крыльев 9,41 м; длина 7,85 м; высота 2,68 м; площадь крыльев 24,25 м2
Полезная нагрузка: до трех пассажиров в закрытой кабине
Flight, March 1932
D. H. "Fox Moth”
A New Economical 4-5 Seater with 120 h.p. Gipsy III Engine
CARRYING pilot and, for short flights, four passengers on a single "Gipsy III" engine of 120 h.p. must be regarded as very economical flying indeed. The new de Havilland "Fox Moth" does this, although normally it is intended for pilot and three passengers, with which load the machine carries fuel for a flight of some 360 miles. Add to this that the new machine will be marketed at less than ?1,000, and it will be seen that the day of cheap flying is not as far away as many appear to think.
The "Fox Moth" owes its inception very largely to Mr. Hagg, Chief Designer of the de Havilland Aircraft Co., Ltd., whose few spare moments are often spent in yachting. Getting to and from the coast quickly, and en famille, has been a very real problem, but with the "Fox Moth" it disappears. Mr. Hagg is himself a pilot, and the little cabin has accommodation for the rest of the Hagg family and the considerable quantities of luggage, etc., which the week-end cruiser needs to take with him. If the machine so admirably meets the requirements of its designer it will meet those of numerous other family men, for whom the "Puss Moth" just falls short of the desired seating capacity.
As a joy riding machine the ''Fox Moth'' should become extremely popular because, by carrying a smaller quantity of fuel than standard, it will take up four paying passengers. The accommodation is not, in that case, luxurious. In fact, it is, as far as the front seats are concerned, rather cramped, but as joy ride flights are usually of very short duration, this should not be really important, and the economy of the machine is such that its operation should net a very substantial profit.
Yet another form in which the "Fox Moth" will have much to recommend it is as the private machine of the man or woman who employs a professional pilot. If real comfort is desired, it can be provided by having but two seats in the cabin, these of the armchair variety, and so placed as to give very ample leg room.
With its cabin stripped, the "Fox Moth" should be a most economical carrier of freight and mails on routes where the volume of traffic is not large enough to justify the operation of a larger and more powerful machine, and finally with three seats and the full amount of fuel the machine should be well suited for air taxy work.
From the foregoing it will be realised that in the "Fox Moth" the de Havilland Aircraft Company have produced a machine with a great variety of uses, and as it has been found possible to get the production cost down to a very low figure, the machine can be marketed at ?995, which must be considered very good value indeed, in whatever form the machine is used.
Getting the Cost Down
The question will naturally be asked: How has it been possible to reduce the price to less than ?1,000? The answer is by using wood construction, and by incorporating as many parts as possible from existing de Havilland types. For example, the wings are, with the exception of minor changes in the roots of the lower plane, the standard wings of the "Tiger Moth." The tail organs are standard "Puss Moth" and "Gipsy Moth." The whole engine unit is identical with that of the "Puss Moth" and "Tiger Moth." Practically the only new large component is the fuselage, and that is of the all-wood type, with flat sides and bottom, covered with plywood.
The "Fox Moth" is the D.H.83 of the de Havilland series, and is a biplane with staggered and back-swept wings. The sweep-back is slightly less than in the "Tiger Moth," and the span is a little greater as the fuselage and top centre-section are wider.
The pilot is placed aft of the wings, and as the top of the fuselage is narrow in front and slopes down to the inverted engine, the view is good.
The cabin is arranged, in the first machine, with a deck chair seat for two across the back, and a single swivelling "bucket" type of seat in front. The passenger can sit facing aft or he can face forward, but his face is then rather close to the engine bulkhead, and the leg room is somewhat restricted.
There is a door in each side of the cabin, and the covering is curved outward to give extra elbow room for the passengers. The curvature extends to the windows, and with the front windows open there is a strong draught clearing the cabin, while with the rear windows open the air is extracted quite gently and without undue draught. Due to the effective silencer and the padding of the cabin, the noise is by no means excessive, and conversation can be carried on without shouting. A telephone is provided by means of which the passengers can converse with the pilot. This telephone is of the single-hand type, with earpiece and mouthpiece mounted together.
The hammock seat in the first machine could be improved by padding the front cross bar of it, but this and other minor points will doubtless be attended to in the production machines.
In the air the "Fox Moth" is much like the "Tiger Moth" in its handling, and pilots appear to be agreed on the pleasant flying qualities of that machine. The glide is flat as a result of the clean design, but the machine can readily be sideslipped if there is risk of overshooting.
From the structural point of view there is little to call for comment in the "Fox Moth." The undercarriage is of the divided type, and the wheels are carried on stub axles, while universal joints are provided everywhere, so that the diagonal bracing struts take no bending loads and are consequently kept very slender and of low air drag. The telescopic struts are substantial, but have to be so in any case, and altogether the undercarriage seems to be a very practical piece of engineering. Bendix wheel brakes are fitted, and a castoring tail wheel enables full use to be made of the individual operation of the brakes, the machine swinging around "on a saucer" when manoeuvring on the ground.
The wings, as already mentioned, are the standard "Tiger Moth" wings, with the exception that the lower plane roots have been slightly altered to permit of folding. The lower wing roots are slightly drawn up at the trailing edge, thus reducing interference and eddy making. The top centre-section contains the streamline petrol tank, and affords gravity feed to the engine.
The plywood covered fuselage of the first machine is of normal construction, but in subsequent machines extensive use will be made of dished steel washers. Experiments have indicated that by inserting these between the nuts and the metal plates, a shrinkage of the wood does not result in any slackness which might reduce the strength of the structure. The plywood is specially protected. First a fabric covering is put on it with cellulose dope, and then an external coat of dope is applied, so that moisture cannot penetrate to the wood.
The tare weight of the "Fox Moth" is about 1,050 lb., and as the gross weight is 2,050 lb. the normal tankage of 25 gallons gives a disposable load of 790 lb. for pilot, passengers and luggage. The maximum speed is approximately 110 m.p.h., and the cruising speed 90-95 m.p.h.
Flight, November 1932
The De Havilland Aircraft Co., Ltd.
Stag Lane, Aerodrome, Edgware, Middlesex
CAPT. GEOFFREY DE HAVILLAND is one of the oldest (aeronautically speaking) British aircraft designers, having designed his first aircraft somewhere around 1908, and having been actively engaged on aircraft design and construction ever since. The present company has been in existence since shortly after the war, and has branches in many of the Dominions overseas.
It was the "Moth" which started the de Havilland Company on its post-war career as specialists in civil aircraft, and more particularly in aircraft suitable for the private owner, and more "Moths" have been built and flown over the world than any other type of aeroplane.
The standard "Moth" with Gipsy II engine is already a familiar sight in almost any country, and needs no description here. A fairly recent version of it is the Gipsy III "Moth," which is offered as an alternative to, and not as a substitute for, the older model. The Gipsy III "Moth" is fitted with the inverted Gipsy III engine, and the view forward is thereby greatly improved. The very clean nose also improves the performance somewhat.
Designed as a "family machine," or for air taxi work, etc., the "Fox Moth" (Gipsy III) is mainly of wood construction, and is remarkable for the high ratio of gross weight to tare weight. In its standard form the machine has seating for the pilot in a cockpit behind the wings and three passengers in the cabin. If desired it can be supplied with four seats in the cabin, but the accommodation is then slightly cramped.
Three standard tankages are provided: 25 gall. (114 litres), 40 gall. (182 litres) and 50 gall. (228 litres). The total permissible weight is 2,070 lb. (940 kg.), and the range will, of course, depend upon the tankage. The pay load also depends upon the tankage, and is 605 lb. (276 kg.) for the smallest tankage and 391 lb. (179 kg.) for the largest tankage. The range varies from 438 miles (705 km.) to 876 miles (1 410 km.).
When the ''Fox Moth'' is fitted with the Gipsy III engine, the maximum speed is 108.5 m.p.h. (175 km./h.) and the cruising speed 92 m.p.h. (148 km./h.). If the new Gipsy Major engine is fitted, the maximum speed is increased to 113 m.p.h. (182 km./h.) and the cruising speed to 96 m.p.h. (155 km./h.).