SLOT-WING PLANES BRING PATENT ROW; Handley Page Declares Curtiss Entry in the Safety Contest Infringes His Device. COUNTER-CHARGE IS MADE But American Concern and Heads of Competition Seek to. The two-seat Handley Page 'Hendon' became a related development of the single-seat Hanley but this ultimately abandoned aircraft program resulted in just six prototypes completed with a first-flight conducted during 1924. Handley Page Ltd Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 1921-05-14 Filing date 1921-05-14 Publication date 1922-05-14 Application filed by Handley Page Ltd filed Critical Handley Page Ltd. Independently of Lachmann, Handley Page Ltd in Great Britain also developed the slotted wing as a way to postpone the stall by delaying separation of the flow from the upper surface of the wing at high angles of attack, and applied for a patent in 1919; to avoid a patent challenge, they reached an ownership agreement with Lachmann.
Flight, March 1930
HANDLEY PAGE TYPE 39Guggenheim Competition Machine
ONE of the articles in last week's issue of THE AIRCRAFT ENGINEER (Monthly Technical Supplement to FLIGHT) was by Mr. Russell, who is in charge of the Handley Page wind tunnel, andДальше>>>dealt with the subject of lateral control by means of automatic wing-tip slots and normal ailerons, interconnected slots and ailerons, and slot and 'interceptors.' In the Handley Page type 39 biplane built for the Guggenheim safe aircraft competition, the Handley Page slot is used in addition to give extra lift, not as in the early Handley Page experiments by mechanically-operated slots and flaps, but by automatic slots and flaps extending over the entire top plane. Thus the pilot is relieved, in this machine, of the work of operating the lift slots. To the best of our knowledge, this is the first time that the slot has been so employed on an actual machine (as distinct from wind tunnel model experiments), and this fact entitles the Handley Page 'Gugnunc,' as it is usually called, to inclusion in FLIGHT'S gallery of new aircraft. That the machine did not win the Guggenheim competition, and that lawsuits and other forms of unpleasantness attended its appearance in America, is neither here nor there, and need not be taken into consideration when trying to form an idea of the merits of this particular use of slots.
The automatic wing tip slots have proved themselves, and have, although they may not represent the ultimate solution of the problem, 'come to stay,' at least for some considerable time. But, in addition, the slot may be used as a 'lift slot' as well as a 'stability slot,' and it is of interest to discover whether, when so used, the slot is likely to become generally adopted. It has been pointed out in FLIGHT that when one comes down to fundamentals it is found that in effect what the slot enables one to do is to reduce the area (for a given landing speed) by reducing the chord only. The wing span is determined by considerations other than landing speed. For taking off and for climbing the span cannot be reduced beyond a certain limit if induced drag is to be kept down. That being so, it might be thought that the lift slot would not be likely to have very great advantages, and that a machine with automatic wing tip slots only could be designed to do all that the lift-slotted machine can do. It is not certain that this is necessarily quite true. For instance, a speed range of 3-36 to 1 (as the 'Gugnunc' has) is not easily achieved in an unslotted machine, and if one did manage to attain it, the machine would in all probability have a gliding angle so flat that it would be difficult for a pilot of only moderate skill to bring it into a small field. The 'Gugnunc,' when flying at large angles of incidence, has a very steep gliding angle because of the higher drag of the wing with slots open, and can, therefore, be brought down more a la Autogiro. Put in another way, with the system of lift slots a pilot of moderate skill can bring the machine down steeply without thereby reaching a high speed, much as the skilled pilot sideslips an ordinary machine. To us it seems that this may be one of the chief features in favour of the lift-slotted aeroplane. That a substantial undercarriage of long travel is needed to take care of the vertical component of such a descent is obvious, but experience with the 'Gugnunc' machine seems to indicate that such an undercarriage can be produced.
The price paid for the ability to make steep descents in safety, and at fairly low speed, appears to be extra horsepower when flying slowly, and, more important still, during a climb. In the illustration on p. 270, of horse-power available and horse-power required with wings normal, and with slots open and flaps down, the horse-power required curve is not continued beyond a forward speed of some 75. ft./sec. (51 m.p.h.), which is probably below the speed corresponding to greatest rate of climb. However, enough of the curve is included to show that the distance between horse-power required and horsepower available curves is smaller than for the normal wing. Roughly, it looks as if the power reserve available for climb would be 55 h.p. for the 'normal' wing, and 40 h.p. for the wing with slots open and flaps down. The curves, it should be pointed out, were not 'estimated' by us, but were supplied by the Handley Page company.
In the 'Gugnunc' the slots extend over the whole span of the top plane, as do also the trailing edge flaps, but near the wing tips the slots are of the usual automatic type, not linked to the flaps, the latter being ordinary ailerons. Over the inner portion, however, the slot is still entirely automatic in action, but is connected to the trailing edge flap, the automatic opening of the slot pulling the flap down. The increase in lift thus obtained is shown in the other graph on this page. The lateral stability at large angles which is a result of fitting automatic wing tip slots is retained in the 'Gugnunc' by the fact that the middle portion (lift) slot, is loaded by the flaps, which tend to keep it closed, and therefore, opens later than the wing tip slots. The fundamental wing section used is R.A.F. 28.
Structurally the 'Gugnunc' is a perfectly normal machine, which does not call for any special comment. Its tare weight is 1,362 lb., and the gross weight is 2,150 lb. The maximum speed has been officially measured to be 112-5 m.p.h., and the minimum speed is 33-5 m.p.h. The initial rate of climb is 570 ft./min. The engine fitted is an Armstrong Siddeley 'Mongoose' of 150 h.p. The wing loading is 7-3 lb./sq. ft., and the power loading 13-75 lb./h.p. The value of the Everling High-speed Figure is 18-9, which is quite good, and indicates that the drag coefficient at top speed {i.e., minimum drag with slots closed and flaps up) is fairly small.
H.P.20 | |
---|---|
Showing open and closed slots and depressed aileron | |
Role | experimental monoplane |
National origin | United Kingdom |
Manufacturer | Handley Page |
First flight | 24 February 1921 |
Number built | 1 |
The Handley Page H.P.20 was an experimental monoplane modification of a de Havilland DH.9A, built to study controllable slots and slotted ailerons as high lift devices. It was the first aircraft to fly with controllable slots.
Development[edit]
Frederick Handley Page obtained his master patent for controllable slots on the edge of an aircraft wing on 24 October 1919.[1] He knew the lift coefficient of all wings increased linearly until the stall was approached, then fell away; he argued that if the stall could be delayed, higher lift coefficients could be reached. In Germany Gustav Lachmann had the same idea, though through a wish to avoid the dangers of stalling.[2] Rather than going to litigation an agreement was reached in which Lachmann, working with Prandtl at the advanced Goettingen air tunnel acted as consultant to Handley Page. Lachmann heard about the Handley Page work when they modified a standard DH.9A with fixed slots and demonstrated it dramatically at the Handley Page airfield at Cricklewood on 21 October 1920. That machine was retrospectively designated the H.P.17. The first aircraft with pilot controllable slots, designed by Handley Page and wind tunnel tested by Lachmann was called the X.4B in the company's contemporary notation but became, retrospectively, the H.P.20.[3] The Air Ministry met the cost.
Like the H.P.17 it used a D.H.9A engine, fuselage and empennage, but fitted with an entirely new wing.[3][4] The H.P.20 was a high-wing monoplane, using a thick wing with a straight leading edge but taper on the trailing edge. It was a semi-cantilever structure bolted to a small cabane on the fuselage and braced to the lower fuselage longerons with a pair of steeply rising struts on each side. The heaviness of early cantilever wing structures is shown by a comparison of the loaded weight of the H.P.20 (6,500 lb) with that of the loaded standard biplane DH.9A (4,645 lb including fuel for over 5 hours of flight and a 460 lb bomb load).[5] The undersurface was flat and the front edge cropped to allow the full span slats, when closed, to form the true leading edge. The slats were hinged ahead of the wing and at their leading edges; their rotation formed the slots. In addition, slots opened in front of the ailerons when they were lowered. This was done via a groove in the wing just in front of the aileron hinge, narrowing towards the top surface.[3]
The spans and wing areas of the DH.9A and H.P.20 were about the same,[6][7] so the wing chord of the monoplane was about double that of the biplane. As a result, the tailing edge extended aft beyond the DH.9A's pilot's cockpit and so the H.P.20 was flown from what had been the gunner's position.[5] There was a small cut-out in the trailing edge to enhance the pilot's view. As there was no upper wing to house the fuel, the H.P.20 had a slightly round-ended cylindrical tank mounted high over the centre section to provide gravity feed. Because high angles of attack were used in landing and take-off with the slots open, the undercarriage was lengthened,[5] as it had been on the H.P.17.[8] There was an airflow direction indicator mounted on a little boom which projected forward of the starboard wing.
The H.P.20 was first flown with slots closed on 24 February 1921 at Cricklewood.[3] About a month later it was flying with controllable slots. In one test it landed at 43 mphh (69 km/h) at a wing loading of 11 lb/ft2 (54 kg/m2),[9] about the same as a Cessna 152. This corresponds to a lift coefficient of 1.17. Aerodynamic loads made the slats hard to operate reliably. After manufacturer's tests, the Air Ministry agreed to take on the aircraft, but the Ministry's pilot made a heavy landing at Cricklewood during acceptance flights and the H.P.20 remained there for repairs until final delivery in February 1922.[3]
Specifications[edit]
Data fromBarnes & James 1987, pp. 229
General characteristics
- Crew: 1
- Length: 30 ft 0 in (9.15 m)
- Wingspan: 47 ft 6 in (14.5 m)
- Wing area: 500 sq ft (46.4 m2)
- Gross weight: 6,500 lb (2,950 kg)
- Powerplant: 1 × Liberty 12-N water cooled V-12 , 400 hp (300 kW)
References[edit]
Bibliography[edit]
Handley Page 0/400
- ^Barnes & James 1987, pp. 211
- ^Barnes & James 1987, pp. 215–6
- ^ abcdeBarnes & James 1987, pp. 212–5
- ^Flight 10 November 1921 p.732-3
- ^ abcFlight 1 June 1956 p.679
- ^Barnes & James 1987, pp. 229
- ^Jackson 1978, pp. 118
- ^Barnes & James 1987, pp. 211–3
- ^Jackson 1978, pp. 115
Handley Page Slots App
Note[edit]
Wikimedia Commons has media related to Handley Page H.P.20. |
- Barnes, C.H.; James, D. N. (1987). Handley Page Aircraft since 1907. London: Putnam Publishing. ISBN0-85177-803-8.CS1 maint: ref=harv (link)
- Jackson, A.J. (1978). de Havilland Aircraft since 1909. London: Putnam Publishing. ISBN0-370-30022-X.CS1 maint: ref=harv (link)
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