P.Lewis British Aircraft 1809-1914 (Putnam)
Flanders F.4
During 1912, the Flanders concern produced four monoplanes for the Military Wing of the R.F.C. to an order from the War Office. The design, designated F.4, was a development of the F.3 Monoplane. Three of the machines, Nos. 265, 281 and 422, were given tapered wings, while the fourth aircraft, No. 439, received a pair with constant chord. Although based on the 1911 monoplane, the new design was a great improvement in many ways, especially in the coil-spring undercarriage, which was completely revised and made far stronger to enable it to withstand the rigours of military usage.
Two wicker seats in tandem were fitted and the engine installed was the eight-cylinder 70 h.p. Renault. The four-bladed propeller was made up by simply superimposing two standard pairs of Regy blades on the same shaft. Conventional controls were used, with warping of the wings, the rudder being hinged to a vertical post without a fixed fin.
The first of the monoplanes was ready at the end of June, 1912, and the batch of four were put through their tests by F. P. Raynham before their acceptance by the R.F.C. Performance was found to be very good indeed, with a speed range of 26.2 m.p.h., a figure which was better than any of those attained by the various designs officially entered in the 1912 Military Trials.
The Flanders Monoplanes were unable to show their worth in service, as the ban on monoplane flying by the Military Wing of the R.F.C. came into force during the following October. However, at the Naval and Military Aviation Day held at Hendon on 28th September, 1912, a modified Renault-engined Flanders Monoplane was present, in which a single upright support was used for the cabane, and whose undercarriage utilized horizontal struts from the sides of the fuselage to carry the shock-absorbing struts of the undercarriage,
SPECIFICATION
Description: Two-seat tractor military monoplane. Wooden structure, fabric covered.
Manufacturers: L. Howard Flanders, Ltd., Richmond and Brooklands, Surrey.
Power Plant: 70 h.p. Renault.
Dimensions: Span, 40 ft. 6 ins. Length, 31 ft. 6 ins. Wing area, 240 sq. ft.
Weights: Empty, 1,350 lb. Loaded, 1,850 lb.
Performance: Maximum speed, 67.2 m.p.h. Landing speed, 41 m.p.h. Climb, 1,000 ft. in 3.5 mins., 1,500 ft. in 5.5 mins., 2,000 ft. in 8 mins.
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M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
FLANDERS F.4 monoplane
The War Office ordered four F.4 monoplanes in late 1911, and these were built in the new works at Townsend Rd., Richmond, before being taken to Brooklands for final assembly and flight trials. The first machine was flying there by 7 July 1912 in the hands of F.R Raynham, the others being transferred there progressively until 1 January 1913, when the last machine made its first flight.
The earlier type of fuselage structure was discontinued and a conventional type of box girder now constituted the primary structure, and a decking was provided around the two cockpits. The undercarriage of the first machine failed to satisfy the rough field requirement, when tested at Farnborough in September, and the machine was returned for modification.
A strengthened undercarriage structure, with separate legs and half axles, was attached direct to the bottom longerons, and was sprung by four rubber cords on each leg. Larger wheels, which did not castor, replaced the original design on all four aircraft. The engine was now air-cooled, thus dispensing with radiators, and a four-bladed propeller was used.
The general configuration was otherwise similar to the earlier F.3 aircraft except for a pair of parallel chord wings fitted to the fourth machine. Steel tapes, chains and sprockets were used to operate the warp control.
Power: 70hp Renault eight-cylinder, air-cooled vee with integral fan and ducting. 2:1 reduction gear driving four blades consisting of two separate 8ft 6in Regy propellers.
Data
Span 40ft 6in
Chord 8ft 6in tapering to 5ft 9in
Area 240 sq ft
Area tailplane 25 sq ft
Area elevators 18 sq ft
Area rudder 10 sq ft
Length 31ft 6in
Height 9ft tail up
Weight 1,350lb
Weight allup 1,850lb
Speed range 41-67mph
Four aircraft built, serial Nos.265, 281, 422 and 439
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Jane's All The World Aircraft 1913
HOWARD-FLANDERS. L. Howard-Flanders, Ltd., 31, Townsend Terrace, Richmond, Surrey. School: Brooklands. Established February, 1912, by Howard-Flanders, whose connection with aviation dates from the pioneer days. Richmond Works opened April, 1912. Capacity of the works at end of 1912 was sufficient to turn out from 25 to 35 machines a year.
F 4 1912. B 2 1912. S 2 1913. F 5 1913. B 3 1913.
2-seater 2-seater single-seat 2-seater 2-seater
military biplane. monoplane. monoplane. biplane.
monoplane.
Length...feet(m) 31? (9.50) 31? (9.50) 28 (8.50) 31 (9.45) 31 (9.45)
Span....feet(m) 40 (12) 40 (12) 35 (10.70) 39 (11.90) 40 (12)
Are..sq.ft.(m?) 240 (22) 390 (36) 190 (17.75) 250 (30) 390 (36)
Weight,total...
.......lbs.(kgs) 1850 (839) 1500 (680) 1180 (585) 1600 (726) 1650 (748)
Weight, useful...
......lbs.(kgs) 500 (227) 450 (204) 350 (159) 600 (272) 600 (272)
Motor......h.p. 70 Renault 40 A.B.C. 80 Gnome 80 Gnome 80 Gnome
Speed, max...
.....m.p.h.(km) 67 (108) 56 (90) 82 (132) 70 (115) 68 (110)
Speed, min...
.....m.p.h.(km) 41 (66) 38 (61 ) 45 (73) 42 (68) 40 (65)
Number built
during 1912 4 1 - - -
Remarks.--F 4 climbing speed 1000 feet (305 m.) in 3? minutes, 1500 in 5? mins., 2000 in 8 mins. B 2 climbing speed 200 feet (61 m.) per minute.
The four F 4 type were bought by the British Army during 1912.
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Журнал Flight
Flight, December 21, 1912.
THE FLANDERS MONOPLANE.
SOME few months since, we devoted an article to describing this extremely interesting monoplane in full. Changes in its design have taken place since then, but as they have affected the detail of the machine more than the general ensemble, let us confine ourselves more particularly to its new features.
Of the Flanders monoplanes, readers may recall, the War Office ordered four. Two of these have been delivered to the Royal Flying Corps at South Farnborough; one is, at the time of writing, at Brooklands, being tested and adjusted prior to being flown over to Farnborough; and the fourth has yet to emerge from the firm's works at Richmond.
The main point of difference of this present 70-h.p. Renault engined monoplane from the 60-h.p. Green engined machine we have previously described lies in the landing gear. The early machine was fitted with a central front skid and swivelling wheels that were supported by a deformable triangle of steel tubing, the resiliency being provided by a compression spring which formed the longest side of the triangle. This chassis, although serviceable enough for landing on and taking off from quite rough surfaces, did not satisfactorily withstand the severe rolling test that is imposed by the War Office on machines before they are handed over to the Royal Flying Corps Landing on and rising from a ground is rather different from rolling over it at, say, 20 miles an hour, for whereas the old type of Flanders chassis could alight on and take off quite comfortably from the test ground on Laflan's Plain, when it came to rolling moderately slowly, the peculiar surface set the machine bouncing so lustily that eventually it gave out. The fault of that chassis, for that particular test, was its extreme resiliency.
The present chassis, however, has been found to be more serviceable, for not only is it stronger, but it is sprung in a manner that does not make the machine tend to bounce to the extent that the old type of landing gear did. Briefly, the undercarriage is composed of a long central skid of hickory - an excellent wood to use by reason of its tough fibrous nature - supporting the body through four V set pairs of ash compression struts. Further strength at the skid is provided by two more pairs of steel tubular struts, which run to the skid, and which are there with the primary object of supporting the warping gear. For the skid itself, it is protected in front on the underside by a steel plate, and at its rear the overhang is sawn longitudinally into three laminations, for that part needs to be flexible on account of its being adjusted to touch ground, and take some of the work from the light tail skid. On either side are the wheels revolving on axles that are hinged to the central skid, and which support the body by a clever form of compression-spring.
In designing a compression-spring of this "single-tube" type, which derives its ability to withstand compression by means of elastic shock absorbers in tension, the chief difficulty has been to overcome the weakness caused by having to split one of the tubes to allow for the travel of the crosspiece to which the tensional springs are attached. This Mr. Flanders arrives at by arranging a third tube over the section where the long slot is cut. If reference be made to one of our accompanying sketches, this detail will undoubtedly be more readily understood.
The wheels are 26 ins. in diameter, and are furnished with 4 in. tyres. Up to the present these wheels have been "disced in" with fabric, but in future models discs of aluminium sheeting are to be employed, as they make a much neater job.
For designers, especially, it is interesting to notice that Mr. Howard Flanders is gradually abandoning his highly original and workmanlike notion of constructing his machine about a central unit distinct from the fuselage. To this unit the wheel-base was attached. On it the main weight of the engine, pilot, and passenger rested, and to it the wings were braced.
The changes that he has made in the landing gear have no doubt given him cause to reconsider the usual plan of making the fuselage serve as the unit of assembly of all parts of the machine, and not merely as a streamline shield for the occupants and as a support for the tail.
In the machine under review, the fuselage is considerably stronger than in the earlier Flanders machines. The longerons are of ash, and they are built up to form a box girder by transverse and vertical members of spruce fitting into aluminium sockets.
Each crossbracing wire in the body is tightened by an ordinary strainer. A great deal of extra strength in the fuselage is arrived at by applying curved strips of three-ply wood to the longerons. These strips are screwed on, and not only strengthen the longerons in the bay between each pair of transverse struts, but render the fuselage much more rigid against torsion.
Regarding the wings, it is most noticeable how the thickness of the wing, the camber, and the angle of incidence diminish uniformly from the root to the tip. At the extreme tip the wing is practically flat and has no incidence. The advantages gained by this special formation, Mr. Flanders claims, are increased efficiency, increased stability, and a warp so well balanced that it renders it unnecessary to rudder when the wings are being flexed to readjust the machine's lateral balance.
From a service point of view, one of the advantages of the Flanders monoplane is its unusually large speed variation.
The second Flanders monoplane delivered to the Royal Flying Corps showed a variation of from 41 to 67 miles an hour. The advantage of being able to land and leave ground at 41 miles an hour and to maintain flight at 67 is too apparent to need any enlarging upon.
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