Flight, April 1934
THE COMPER "STREAK"
LT. COMPER and those associated with him are to be congratulated on their enterprise in challenging the French constructors for the Deutsch de la Meurthe Cup. With the withdrawal, announced last week, of the Italian entries
for, it is believed, the reason that the machines and engines could not be sufficiently developed and tested in time for the contest, Great Britain will be the only non-French challenger, and the Comper "Streak" will be the only British entrant. What makes the British challenge so courageous is the fact that the "Streak" is fitted with the de Havilland "Gipsy Major" naturally-aspirated engine, which is of but 6.125 litres capacity, while the French machines will be able to call upon all the power that can be got from supercharged engines of the full 8 litres capacity permitted by the Coupe Deutsch regulations. This means that Comper will have to face competitors with more than twice his power at their disposal. Comper's performance estimates indicate, however, that his machine should not be nearly so inferior to the French as the difference in power might lead one to imagine. The effect of engine power is cumulative, and the larger and more powerful engines require correspondingly more fuel in a given time, which means that the machine itself must be larger and of greater wing area if the landing speed is to be kept down to reasonable limits. Everyone in British aviation will wish Flt. Lt. Comper all possible good fortune in his plucky attempt to wrest the Coupe Deutsch from the French defenders.
Last year Flt. Lt. N. Comper, Chief Engineer and Technical Director of the Comper Aircraft Co., Ltd., put a "hotted up" "Gipsy Major" engine into one of his little high-wing monoplanes, and in the face of very great handicap and serious competition raced it for the Coupe Deutsch de la Meurthe in France. The story of his gallant fight was recorded in FLIGHT for June 8, 1933. In our issue of FLIGHT for May 11, 1933, we were able to publish a general arrangement drawing showing a development of a new machine called the "Streak," designed chiefly for races of this nature - which, incidentally, Flt. Lt. Comper's experience in France had shown him to be desirable. The original "Streak" was, we believe, designed with the idea of competing in the International Air Races which a committee attempted to organise at Portsmouth last year. Unfortunately, these races did not mature, and the "Streak" never, therefore, came out. This year Flt. Lt. Comper has again decided to compete in the French event, and on Thursday, April 12, the machine was flown successfully.
During the first flight of the "Streak," made by Flt. Lt. Comper himself, the new machine proved itself perfectly balanced, and it was found that control and stability were good. One possible exception was formed by the ailerons, which were found to be surprisingly sensitive. So much so, in fact, that flutter developed. In this connection it should be pointed out that the mass balances designed for the ailerons had not yet been fitted, and it may be that when this has been done the trouble will disappear. The flutter occurred at high speed only, and modern theory indicates that in nearly all cases a tendency to flutter can be cured by mass balances.
Since January, 1930, when we were able to publish the first full description of the Comper "Swift," which at that time was fitted with the A.B.C. "Scorpion" engine, a great deal of development has taken place. As our photographs show, subsequent development was the production of a "Swift" with a Pobjoy engine, then a "Swift" with a "Gipsy Major" engine, and more recently a low-wing high-performance monoplane called the "Mouse" (see FLIGHT for September 28, 1933).
Flt. Lt. Comper, with his Technical Assistant, Mr. A. A. Fletcher, have by their experience with this latter machine, been able to produce the "Streak," and this machine is in effect a modified "Swift" fuselage put on to a scaled-down "Mouse" wing. The result is a very up-to-date high-performance machine, which may equally well be used for racing or for the fast transport of things like Press photographs. Points which will immediately be noticed, besides the general clean lines, are the retractable undercarriage and the modification of the top decking of the fuselage behind the "Gipsy" engine, to new curved lines. As in the "Mouse," the wheels of the undercarriage are stowed slightly below the bottom of the wing when the undercarriage is retracted, forming an excellent safety device in the case of forced landings on soft or bad ground. The "Mouse" has already been landed with the wheels retracted without any damage whatsoever other than bending the airscrew tips, and even that may be avoided if the airscrew is so mounted that it stops in the horizontal position. Landing the machine like this, while it is true it may result in slight damage to the bottom of the fuselage, does remove any possibility of the machine turning over and damaging the occupants, a matter of no small importance in the case of the "Streak," which has a wing loading as high as 18.75 lb./sq. ft. (91,54 kg./m2).
Structurally the fuselage differs in its main essentials very little indeed from the "Swift." It consists of spruce longerons, rigidly braced by spruce struts in W form with three-ply gussets of ample size, and the whole is fabric covered. Modifications have, of course, been made to the bottom longerons in the centre portion of the fuselage, where it is placed over the wing.
The fairing over the rear part of the fuselage is of doped fabric over a light framework of spruce stringers. Between the fireproof bulkhead and the pilot's windscreen a sheet aluminium cover over the main fuel tank forms the top front decking and continues an excellent line back from the engine fairing.
The wing is made up as a complete unit with box-section plywood and spruce spars; an ingenious joint allows the webs to be continuous, although the centre portion of the spar is horizontal and the outer portions of the wing beyond the undercarriage housings are turned up to give a 5 deg. dihedral angle. The ribs have solid three-ply webs with double spruce booms, and the three-ply covering over the whole wing removes any necessity for separate drag bracing. The ribs on either side of the undercarriage recesses are of laminated spruce, and steel tubes carry the drag stresses in the region of these recesses. The aileron spars are channel section spindled from spruce, with a three-ply web across the jaws of the channel. The ribs are constructed much in the same way as those of the wing, and a three-ply covering is also used. Our sketch shows the small fibre gear wheels in the wing which transfer the motion of the aileron control cables from the control column via external rods and levers to the ailerons themselves.
The tail plane has spindled spruce spars, spruce and plywood ribs and is fabric covered, the elevator also being of the same construction. The rudder and fin, however, have steel tube posts with flanged steel plate ribs, spot welded to sleeves which are pinned to the posts, the leading edge and trailing edge also being steel tubes. The controls are by cross-shafts, rocking levers and cables, following normal practice. The tail skid is a straightforward one composed of leaf springs. In the pilots cockpit a large dashboard carries the usual range of Smith's instruments, including one of their latest Turn and Bank Indicators, and a Reid & Sigrist pitch level.
Our artist's impression of the centre-section, which carries the pilot's controls, shows how well placed are items like the operating handle for the undercarriage on the starboard side and the brake lever on the port side. In order to assist the pilot as much as possible without increasing the drag of the machine, transparent windows have been let in either side of the fairing below the wind-screen, and by them his view is quite considerably enhanced.
The engine mounting, carrying the special "Gipsy Major" engine, is a straightforward one of square-section welded steel tubes. The fuel system consists of a central tank mounted in the fuselage in front of the pilot, carrying 29 gall. (132 litres), and two wing tanks in the centre portion of the wing either side of the fuselage, having a capacity of 8 1/2 gall. (38.6 litres) capacity each. The engine is supplied with fuel by dual pumps of de Havilland manufacture. The cowling round the engine is of sheet aluminium. It is particularly neat and gives the fore part of the machine very clean lines, at the same time providing adequate cooling. The side panels of the cowling are on vertical hinges at the front end and are secured, as are the top and bottom detachable panels, by the new Thompson-Boothby cowling clip. The oil tank, in keeping with Comper practice, is cooled by a direct air inlet on the port side, carrying cold air from the outside of the machine through a tube running through the middle of the tank, and exhausted by a vent placed where the starboard wing root joins the fuselage. The engine drives a Fairey metal propeller.
The undercarriage differs but slightly from that fitted in the Comper "Mouse." Only one compression leg is fitted either side of each wheel, and these legs are of the type now so well known, which is designed and manufactured by Mr. G. H. Dowty, of Aircraft Components Co., Cheltenham. Our artist's sketch explains clearly the neat manner in which the locking pins are withdrawn when it is desired to raise the landing gear. Each unit comprising the structure carrying the compression legs and ultimately the wheel itself is, of course, entirely separate from the other except that a cross shaft enables the sprocket and chain drive in the cockpit to raise and lower both wheels simultaneously. Dunlop wheels and tyres are fitted, the former being the A.H.6 16-in. type and the latter 6-in. by 6 1/2-in. medium pressure, and the brakes are Bendix.
Flight, May 1934
A NEW SPORTS MODEL
The Comper "Kite" is a two-seater version of the Comper "Streak," but is being produced in response to numerous requests for a two-seater "Swift"
RARELY if ever in the history of flying has the secret of a new aircraft type been so closely guarded as that recent maintained by the Comper Aircraft Co., Ltd., of Heston. Usually, some sort of rumour leaks out, and quite a number of people know when an aircraft firm is about to bring out a new model. In the case of the Comper "Kite," the announcement has come as a complete surprise, and the "Streak" with which Flt. Lt. Comper will challenge the French constructors for the Coupe Deutsch was generally looked upon as the latest Comper type. Hot on its heels now follows the "Kite," which is in effect a two-seater version of the "Streak." The manner in which the firm came to decide on the production of the "Kite" is interesting and deserves to become known.
Although a fairly large number of Comper "Swifts" were built and sold, it gradually became evident that no single-seater, no matter how appealing in its flying characteristics, would ever command a very large sale - certainly not one running into hundreds. One has often heard it stated that the "Swift" was an extremely nice little machine, but the admission was usually accompanied by the wish that Comper would produce a two-seater "Swift." If one thinks of the general lay-out of the "Swift," it at once becomes obvious that to turn it into a two-seater would be almost impossible. The high-wing arrangement, with the fuselage "hump" supporting the centre of the wing, precluded any sort of arrangement in which the passenger could get a reasonable view and fairly easy access to his cockpit. From a weight-carrying point of view, the "Swift" would have carried the equivalent of another person easily, even remaining in the "Acrobatic" category while doing it. But space was the difficulty.
Then Mr. Comper produced the "Streak" as an out-and-out racing type. With the exception of the initial wing flutter, which came as a complete surprise in view of the great stiffness of the wing, and which has since been completely cured by fitting ailerons of narrow chord and provided with mass-balances, the "Streak" proved to have quite remarkably good flying qualities. Not only is the speed excellent for the power of the engine fitted, but the controllability and manoeuvrability are far better than would be expected in a racing type, while the take-off and landing resemble those of an ordinary touring machine.
A Good "Kite"
With the demand for a two-seater "Swift" in mind, and with the high performance and general handiness of the "Streak" an established fact, the decision to introduce the "Kite" was a logical one. The more difficult type, the racer, had already been found to have good qualities. The low-wing arrangement lent itself very readily to the addition of a second seat. The chain of argument was complete. The only point to be settled was the choice of engine. Because of its low specific weight, and with very good service of the "R" type in many "Swifts" in mind, the choice fell on the new Pobjoy "Niagara" of 90 h.p. The "R" engine, it will be recalled, was fitted in "Swifts" which made some famous long-distance flights, such as England-Australia, England-Cape Town, Madrid-Manila, and twice over the Andes mountains. The Comper company is so satisfied with the running of the "Niagara" that it expects equally good results from it in the "Kite."
Having followed the logical steps which led to the introduction of the Comper "Kite," we may devote a little attention to the features which promise to make it a very popular type as soon as it is on the market. High performance is the first notable characteristic. The performance figures are, of course, at present the calculated figures, but in the past Flt. Lt. Comper has not been very far "out" in his estimates, and the fact that the machine so nearly resembles the "Streak" should be a further reason for close prediction. With a maximum speed of 155 m.p.h. (250 km/h), it is estimated that the cruising speed will be about 140 m.p.h. (225 km/h). That the "Kite" will be a useful as well as fast sports type is indicated by the fact that with full load of pilot, passenger and luggage, the range at cruising speed is calculated to be some 700 miles. This range should be ample for the requirements of most owners, and will allow of quite long flights against strong head winds. With a tare weight of 670 lb. (304 kg.) the gross weight will be approximately 1,200 lb. (544 kg.), so that the ratio of gross to tare weight is 1.76, the machine carrying 76 per cent, of its own weight as disposable load.
In general construction the "Kite" will be identical with the "Streak" described and illustrated in FLIGHT of April 19, 1934. The only exception will be the nose portion of the fuselage, which will be extended to take the Pobjoy "Niagara" engine. The passenger will sit approximately over the centre of pressure, so that the trim will not be affected.
Our general arrangement drawings show the lines of the "Kite," and also the main areas. An impression of how the machine will look when flying is given on page 462. No illustrations and no figures can give a real impression of how the machine will handle, but the behaviour of the "Streak" promises well for the new sports type, the first appearance of which will be awaited with interest.
Flight, July 1934
NEW AEROPLANES IN KING'S CUP RACE
Early this year (in Flight of May 10, 1934) we gave the first details of this new sports model, which has been produced by the Comper Aircraft Co., Ltd., of Heston. The one which Flt. Lt. E. H. Healy is flying in the race has been entered by Sir Norman Watson, the chairman of the company, and, in view of the present demand for a high-speed touring machine which is both light and cheap, its performance will be watched with particular interest. Basically, it is a two-seater version of the Comper "Streak" which Flt. Lt. Comper flew in the Coupe Deutsch, and is also flying in the King's Cup Race; but, whereas the latter machine has the ''Gipsy Major'' engine, the "Kite" will be powered with the new Pobjoy "Niagara." Structurally, the "Kite" is very like the “Streak” - that is to say, the fuselage is of spruce with strut bracings, and fabric-covered, while the wing, which also is mainly of timber, is ply wood-covered. Both the "Kite" and "Streak" will, of course, be in the "aristocratic'' class of machines having retractable undercarriages. The two wheels are mounted in pyramids of steel tubing, pivoted near the front spar of the wing, and interconnected by a tube across the fuselage. When in the retracted position, the two wheels are swung upwards and backwards about this pivot, coming to rest when somewhere about a quarter of the wheel remains exposed beneath the lower surface of the wing. Designers are by no means yet unanimous as to whether this is the best arrangement, or whether the fully retracted wheel is to be preferred. The adherents of the former system maintain that theirs is the best, because a fast, fairly heavily loaded aeroplane can, in a case of emergency, be landed on rough ground with the wheels retracted without any fear whatsoever of the machine turning over. This has been proved in practice, and has been done without any damage to the machine other than bending the metal airscrew.
POBJOY "NIAGARA," 90 H.P. ENGINE.
Span 23 ft. 6 in. (7,2 m)
Aspect ratio 5.8 to 1
Wing area 80 sq. ft. (7,4 m2)
Gross weight 1,360 lb. (612,4 kg)
Tare weight 750 lb. (34,0 kg)
Wing loading 16.8 lb./sq. ft. (82,0 kg/m2)
Power loading 15 lb./h.p. (6,8 kg/hp)
The Streak shortly after roll-out at Heston in April 1934.
CLEAN LINES: The "Gipsy Major" engine of the Comper "Streak" has been very cleanly faired in, but the cowling at the same time provides adequate cooling. Another view of the Streak before the addition of mass-balances.
RACY LOOKING: The two views of the new Comper "Streak" bring out the racy lines of this machine.
The head-on view, more particularly when the landing gear is retracted, shows how clean it is possible to get a machine of this nature.
J. Graham, Comper works manager, surveys the Streak, with Comper sitting in the cockpit, at Heston in April 1934.
THE COMPER "STREAK": In a recent issue of "Flight" we reported that a certain amount of aileron flutter had arisen. By giving ailerons a very narrow chord and fitting mass-balances, as indicated by the illustration, the trouble has completely disappeared.
Flt Lt Nicholas Comper at the age of 36, about to demonstrate the Streak for Flight’s photographer.
ROOT DETAILS: The finished "Streak" will in all probability be heavily filleted at the wing roots. Near the leading edge can be seen the exhaust for the cooling air which is led through the oil tank. The windows in the sides of the pilot's cockpit should also be noted.
Photo shows Flt Lt Nicholas Comper flying the Streak shortly after mass-balances were added to the ailerons.
This Comper Streak, which has a retractable undercarriage, may be the fastest machine in its class. It is to be flown by P. de W. Avery (No. 8).
The Streak demonstrates its smart take-off capabilities at Heston.
The Streak, bearing civil registration G-ACNC, makes a low flypast at Heston in April 1934 for the benefit of Flight’s photographer. Note how the retracted wheels protrude, and the glazed panel just below the windscreen affording the pilot additional vision forward and downward.
The Streak at the time of the 1935 King’s Cup race. Note the addition of undercarriage doors - presumably an attempt to coax extra knots out of the racer.
Types of Machine in the King's Cup Race (4) Comper "Kite," Pobjoy "Niagara" 90 h p engine.
A COMPOSITE PICTURE: Showing how the "Kite" will look when flying.
NEW SEATING ARRANGEMENT: The additional bay to carry the new engine mounting for the Pobjoy "Niagara" is also shown.
DESIGN AIDS TO SPEED (4) Shows how Flt. Lt. Comper arranges the aileron balance and pilot head on the wing tip of his "Kite."
DESIGN AIDS TO SPEED (7) On the rudder of both his "Streak" and "Kite," Flt. Lt. Comper arranges the mass balance as an arc working through a slot in the fin.
COMPER'S UNDERCARRIAGE: Both the Comper "Streak" and the new Comper "Kite" have their undercarriages retracted straight back by mechanical means.
RETRACTABLE: On the right is a perspective sketch showing the general details of one side of the retractable landing gear, and on the left is the mechanism whereby the locking pins are withdrawn preparatory to raising the landing gear.
FUSELAGE DETAILS: In these sketches our artist brings out very clearly the constructional details of the central portion of the fuselage. On the right, the lever which raises and lowers the undercarriage.
Comper "Streak". Gipsy "Major" engine.
Comper "Streak" Gipsy "Major" Engine
Comper "Kite" 90 hp Pobjoy "Niagara" Engine