De Havilland DH 60
The hoped-for boom in private flying after the 1914-18 War did not materialise and the Government realised after a few years that the only way to get people into the air would be by subsidising the flying clubs. Both the Air Ministry and the Daily Mail offered prizes for the best single and two-seat lightplanes, but the resulting Light Aeroplane Competitions at Lympne produced machines that were really far too small and light for club and training work.
Realising this, de Havilland got down to the task of designing and building a really practical little two-seater. They determined that it would have to sell for not more than £600, be simple and safe enough for anyone to fly, and have folding wings so that it could be towed behind a car and kept in a reasonable-sized garage.
As no suitable engine was available, de Havilland got an engine designer friend of his, Frank Halford, to cut a Renault V-8 engine in half, making an inline four out of it. Halford had such a four-cylinder engine running in just nine weeks - the Cirrus. The only entirely new major component was the crankcase. The cylinders and head were identical to those on the old V-8s, as was the five bearing crank, which now had to carry but half the former loads.
The result of these combined endeavours was the prototype DH 60 Moth, G-EBKT, with 44.7kW / 60 hp Cirrus engine, which de Havilland flew for the first time on February 22, 1925, from the company's Stag Lane aerodrome.
The Moth's construction was robust but definitely simple. The Moth was all carpentry: wood spars and ribs and inter-plane struts; wooden longerons for the fuselage, ply-covered to make it as strong as a box. To fold the wings, you pulled forward the pins that locked them to the center section, inserted a wooden jury strut to prevent the top wing from sagging, then folded them back on hinges at the rear spar and clipped them to the body - it took just two minutes. The Cirrus sat high up on a forward extension of the top wooden longerons, with its four cyl-inders and valve gear exposed to the slipstream. The engine was fed by gravity through a copper pipe from an airfoil-shaped 24-gallon tank fitted in the center section of the top wing. A long exhaust pipe ran back past the two open cockpits, and this plus the engine's slow rotation speed made the Moth extraordinarily quiet.
You spoke to the other occupant through a gosport tube. There were no brakes, but the swiveling tail skid was connected to the rudder, so you could steer easily across the meadow. The little Moth spanned 30 feet, weighed just 770 pounds empty (1,350 loaded), could better 90 mph and cruise at 80, climbed at 430 fpm, touched down at 40 and enjoyed a very light wing loading.
The Moths were powered by engines ranging from the 60 hp A.D.C. Cirrus I to the 105 hp Cirrus Hermes.
DH60 Genet engine
de Havilland invited the London press for demonstration rides a few days after the first flight; he entered (and himself flew) Moths in all the air races, including the King's Cup; with his wife as passenger, he set an altitude record in a later Gipsy Moth at almost 20,000 feet.
His first sales breakthrough came from the British Government which ordered Moths for five flying clubs (the first flying clubs in the world) then being set up with state subsidies. The Moths cost £2 15s. an hour to operate; with the subsidy, the clubs needed only to charge 30s. an hour dual and £1 solo. Twenty pounds would get you a private pilot's license. By contrast, a new Moth cost £885 to buy in 1925.
de Havilland steadily developed the airplane, adding automatic leading-edge slats to the top wing and restructuring the fuselage in steel tube. He improved its Cirrus engine, and then, when the stock of war-surplus motors from which the Cirrus was concocted ran short, got Halford to design a new but similar engine, the 100 hp Gipsy. It was fitted in the D.H.60G Gipsy Moth, which was used by many of the record-breaking pilots of the thirties, including Amy Johnson, as well as for club and private flying.
The first Moth was flown by Alan Cobham from London to Zurich and back in a single day on 29 May 1925; and in 1927 Moths accomplished the London-Cape Town return flight and won the first prize for aerobatics at the Copenhagen International aeroplane meeting.
As production of the early models tapered off, the improved DH-60M Gipsy Moth was introduced in 1928. The Gipsy featured a welded steel-tube fuselage, folding wings, and engine options up to 120 hp. Three years later the engine underwent a major modification. In order to lower overall height and improve forward visibility but to raise the propeller shaft height, the engine was inverted as the Gipsy III.
This new DH60 became the DH60G-III Moth Major but still with wooden fuselage. As a result of interest being shown in de Havilland's D,H.60M “Metal Moth" as a cheap introduction to combative military operations, de Havilland built in November 1930 what they described as a "D.H.T. (Training) Moth". Essentially a D.H.60M with a de Havilland Gipsy II engine with an inverted fuel system, aircraft No 1672 was complete by December 5.
Following review, the company decided that it could be further improved; anchorage of the front and rear lift wires was repositioned, allowing unhindered access onto the walkway and the root ends of the upper mainplanes were cut away to improve the upward view.
Designated as a D.H.60T Moth Trainer and registered G-ABKU on April 1, 1931, it was despatched to the Aeroplane & Armament Experimental Establishment (A&AEE) at Martlesham Heath under de Havilland's test marks E.3, but was dismantled in July and "reduced to redundant stock".
Moths were also built at Lowell, Massachusetts, fitted with Wright-built Gipsy engines and sold by the Curtiss Flying Service Organization. The Moth Aircraft Corporation became a division of Curtiss-Wright, and production was moved to Robertson, Missouri. Nearly 200 Moths were built in the U.S. before the deepening Depression killed the venture in 1931.
To assist hangerage, the wings folded to reduce the width to 9 ft 8 in.
The DH60G was also built under licence by Marane Saulnier of France. The DH60G III Moth Major, similar to the Gipsy Moth but with the engine inverted.
A "one off" specimen DH60M was built in the United Kingdom in 1929 for the 1930 Round Europe Touring Competition as G-AAXG (later ZK-AEJ), the metal fuselage Moth was fitted with a 120 hp Gipsy II engine. The fuselage was basically a "rounded off 60". The elevator and rudder were same as the later Tiger, however the wings provided a slightly different profile. The differences with the rest of the DH.60 clan come with the engine installation, a standard Gipsy II of 120 hp, two inches lower than the standard, and a slimmer than usual wing tank. A 15 gallon tank was made to fit into a faired over front cockpit.
The DH60T was a strengthened DH60M with a welded steel fuselage for export and military use and powered by 120hp. Capable of carrying 4 20 lb practice bombs under the fuselage. Compared to the civil DH60, to assist escape from the front cockpit, the rear flying wires were angled forward to the front wing root fitting The cockpit doors were also deepened. But the centre section struts still enveloped the front cockpit so to meet specification 15/31 for a new trainer these were moved forward: this markedly improving egress with a parachute. To reduce the effects of centre of gravity and centre of pressure changes caused by the now forward staggered upper mainplanes, the wings were swept back 19 inches, measured at the tips. A 120-bhp Gipsy III inline motor was installed with the sloping line of the upper engine cowl enhancing the visibility for the instructor in the front cockpit. Eight DH60Ts were built but now called the “Tiger Moth”. Then it was decided that the dihedral of the lower wings needed to be increased to reduce damage during training. This aircraft was redesignated and became the DH82.
Altogether some 2058 versions of the DH-60 Moth series were built, from Cirrus Moth to Moth Trainer, in England during the seven years of production, with an additional 150 built by Moth Aircraft Co. of Lowell, Massachusetts, from Cirrus Moth Trainer. And some 685 were of the “G” variant, 595 of these being built at Stag Lane, and the rest overseas. Amy Johnson flew from England to Australia in one, the then Prince of Wales bought one, at the peak of its popularity about three new aircraft were produced each working day at Stag Lane.
The Moth was selected by all the British Flying Clubs formed under the Air Ministry scheme. In addition to the home markets, many civil examples were exported and military models delivered to air forces as tandem two-seat trainers, including those of the UK, Australia, Irish Free State, Sweden, Finland, Japan and Canada. Moths had been licence-built in Australia, Finland and elsewhere. Other engines fitted included the 63.3kW Cirrus II, 67kW Cirrus III (as installed in the D.H.60X) and 56kW Armstrong Siddeley Genet (as the Genet Moth).
The RAF ordered 134 Moths. By 1939 most of these original aircraft had been retired but with the outbreak of war the RAF impressed at least 146 civilian owned Moths. They were used for a wide range of miscellaneous communication activities.
During 1929-36 and 1939-43, fourteen DH60Gs were used by the New Zealand Air Force for training and utility work. One, ZK-ADT Huia, was owned by National Airways Corp during April-September 1947.
DH60 Cirrus Moth
Engine: ADC Cirrus 1 four-cylinder, 60 hp
Prop: 6 ft 4 in (1.93 m) dia 2-blade
Wingspan: 30 ft / 9.14 m
Length: 23 ft 8 11 in / 7.23 m
Height: 8 ft. 9.5 in
Wing area: 243 sq.ft / 22.58 sq.m
Weight empty: 770 lb
Gross weight: 1,240 lb / 562 kg
Max speed: 91 mph.
Cruising speed: 80 mph / 129 km/h
Typical range: 320 miles / 515 km at 80 mph
DH 60 Moth
Engine : DH Gipsy I, 99 hp
Length : 23.819 ft / 7.26 m
Wingspan : 29.035 ft / 8.85 m
Wing area : 225.291 sq.ft / 20.93 sq.m
Max take off weight : 1351.7 lb / 613.0 kg
Max. speed : 79 kts / 146 km/h
Wing load : 5.95 lb/sq.ft / 29.0 kg/sq.m
Range : 278 nm / 515 km
Crew : 2
DH 60 Moth
Engine 120 hp de Havilland Gipsy II
Length 23ft 11 in
Wing area 243sq.ft
Gross wt. 1,750 lb
Empty wt. 920 lb
Maximum level speed 105mph (91kt)
Normal cruise speed 85mph (74kt)
Initial climb rate 720 fpm
Range 320 miles
Ceiling 18,000 ft
D.H.60G Gipsy Moth
Engine:1 x de Havilland Gipsy I inline, 75kW/ 100 hp
Take-off weight: 748 kg / 1649 lb
Weight: 417 kg / 919 lb
Wingspan: 9.14 m / 30 ft
Length: 7.29 m / 23 ft 11 in
Height: 2.68 m / 8 ft 10 in
Wing area: 22.57 sq.m / 242.94 sq ft
Max. speed: 164 km/h / 102 mph
Cruise speed: 137 km/h / 85 mph
Ceiling: 4420 m / 14500 ft
Range: 515 km / 320 miles
de Havilland DH60G Gipsy Moth
Engine: de Havilland Gipsy I, 85 hp
Price 1929: 650 pounds
Speed: Maximum level 102 mph
Altitude: Maximum ceiling 14,500 ft
Range: 320 miles
DH60G-III Gipsy Moth
Engine: Gipsy III, 120 hp
Engine: Gipsy I, 100 hp
Max speed: 102 mph
Range: 320 miles
Engine: Gipsy III, 120hp