Flight, January 1923

THE PARIS AERO SHOW 1922

HANDLEY PAGE, LTD., CRICKLEWOOD

   As already mentioned, the only British machine exhibited at the Paris Aero Show - the Handley Page "Hanley" Torpedo 'plane, with slotted wings - was greatly handicapped, owing to being placed in an unfavourable position under the gallery. Nevertheless, most of the general public, and certainly all the representatives of foreign Governments who visited the Show, ultimately found their way to the Handley Page stand, and were greatly interested in the unusual design. Incidentally an interesting comparison was afforded by the Pierre Levasseur Torpedo 'plane, which is somewhat similar to the Blackburn "Swift." Although considerably smaller than the P. Levasseur machine, the "Hanley" lands much slower, and, as a matter of fact, we believe that it is intended further to reduce the wing area, as the landing speed is lower than it need be. The "Hanley" will then be an extraordinarily small machine for the load it carries - an important consideration for a machine to be housed on board a ship.
   As regards details of the "Hanley," a very full description, illustrated by scale drawings, sketches and photographs, was published in our issue of November 30, 1922, and consequently there is little need to repeat the description here. Suffice it to place on record that the machine was exhibited, and that the slotted wings and ailerons attracted a great deal of attention from those who follow closely the latest developments in aeronautics. It is now generally realised that sooner or later the slotted wing is bound to play an important part in aviation developments, although at the present time it must be considered to be mainly in the experimental stage. Future progress will be mainly a matter of full-scale research and experiment, which cost a great deal of money, and it may be some time yet before the full advantage of the slotted wing discovery is realised. In the meantime, it may be stated that, in addition to the "Hanley," several other types are now being produced at Cricklewood, although no detailed reference to them is permissible at the moment.

Flight, July 1923

Gothenburg International Aero Exhibition 1923

THE MACHINES

Handley Page, Ltd., Cricklewood

   THE Handley Page exhibit is one of the most interesting machines in this section, in that it represents what may be said to be the first "production" example of the application of the Handley Page slotted wing to a service-type machine. It is, of course, not the first appearance, as a similar machine was exhibited at the last Paris Salon.
   The machine in question is the "Hanley" No.143 torpedo carrier, and is intended for duties with the fleet. As we have pointed out elsewhere, the designing of a machine for this class of work presents several problems which are by no means easy to solve. In the first place dimensions must be kept down to a minimum, folding wings being a desirable feature, and, secondly, the machine must combine low landing-speed and quick get-off for safe "deck work," and at the same time possess a high degree of manoeuvrability for its duties when once in the air. Several designers have given a great deal of attention to this somewhat complicated question, and of the special machines which have been produced to attain this end, the Handley Page incorporating the slotted wing is not only one of the most modern, but the practical tests which have been carried out up to the present appear to promise an entirely successful issue.
   We do not propose here to go into the theory of the slotted wing, as this would entail a somewhat lengthy article in itself, and this subject has already been dealt with on more than one occasion in FLIGHT. We will, however, briefly set forth the general features of the "Hanley" as a whole, together with the following notes referring in particular to the slotted wing. It may be mentioned that a detailed description of this machine appeared in FLIGHT for November 30, 1922.
   The wing section used is 0/100 or a slightly modified form of R.A.F./3, with front slot. In the original wing the auxiliary aerofoil is pivotted about a point towards the nose.
   There is a 50 per cent, increase in lift on opening the slot, enabling the speed to be reduced by more than 12 m.p.h. on a machine with 11 lbs./sq ft. loading.
   Slotted ailerons are also used to increase the rolling moment of the machine, thereby considerably improving the lateral control at low speeds.
   In the latest development of this wing, however, there is a slight modification. Here, instead of the pivotted thick section for the auxiliary aerofoil, one of the single surface type has been adopted. By moving this aerofoil forward to open the slot and backward to close same, several advantages accrue. The main features are the increase in area obtained (this can be of the order of 10 per cent.) and the non-movement of the centre of pressure on opening the slot, due to the forward movement of the auxiliary aerofoil balancing the backward movement of the centre of pressure. With the first type of auxiliary aerofoil, on opening the slot the centre of pressure moves back and has to be corrected by tail adjustment. This has now been entirely eliminated. Not the least important quality of the slotted wing is that it renders a machine practically "un-stallable."
   Turning now to the general design of the machine itself. It is a tractor biplane with a rectangular section fuselage, built-up on more or less orthodox lines, being of girder construction with spruce longerons and struts, braced by streamline wire and tie-rods.
   In the nose of the fuselage is a tubular structure, entirely separated from the main portion of the fuselage by a metal-covered bulkhead, for the mounting of the Napier "Lion" engine. The oil tank is mounted behind the engine, but the petrol tank is located in the fuselage behind the bulkhead.
   A number of rubber-proofed floatation bags are housed within the fuselage aft of the pilot's cockpit, for the purpose of keeping the machine afloat should a descent be made upon the water.
   Built as an integral part of the fuselage is a lower plane centre section, extending outwards for a short distance on each side of the fuselage and braced thereto by sloping struts. On this section are mounted the lower wings, which are hinged at the rear spar so that they can fold back. The mechanism for operating the slot is carried on the front spar of the centre section, and also the fitting for locking the wings.
   The upper wings are carried by a top centre section supported on the fuselage by sloping struts, Apart from the slot gear, the main planes are of more or less orthodox construction, the spars being box form, of spruce, and the ribs of the lattice type. The slotted ailerons are fitted to both upper and lower planes.
   The tail plane is of the trimming type, adjustable during flight, to which is hinged the divided elevator, whilst the rudder has a triangular balance working in a cut-out portion of the vertical fin. The controls are of the standard type.
   The undercarriage has been specially designed to accommodate the torpedo, and, in consequence, is of comparatively wide track. The pilot's cockpit is located just aft of the trailing edge of the top plane. In addition to the usual instruments it is "furnished" with a few extra "gadgets" connected with the slot control and torpedo gear.
   On the whole it is a most interesting machine, calling for a thorough inspection.

Flight, July 1926

THE HANDLEY PAGE "HENDON"
New Slot-Control Machine Demonstrated

   SINCE Mr. Handley Page in this country and Dr. Ing. Lachmann in Germany first invented the slotted aerofoil more or less simultaneously, the progress made with this device has appeared somewhat slow, certainly more so than many enthusiasts had expected, and it is a somewhat curious fact that hitherto not a single commercial aeroplane in use in this country has been fitted with slotted wings. In Germany, on the other hand, at least three machines have been built incorporating this feature. The Udet firm of Munich produced a slotted-wing monoplane last year. The Albatros Works, of Berlin-Johannisthal, turned out a newspaper carrier, a biplane with slotted wings, early this year designed by Dr. Lachmann, and finally another Udet machine was entered at the eleventh hour for the German seaplane competition that is just coming to a close at Warnemunde. In this country, on the other hand, the slotted wing has so far been used on service type of aircraft only, of which the Handley Page Company has built several. One of the latest to be produced at Cricklewood is the "Hendon," a torpedo carrier fitted with Napier "Lion" engine. Hitherto regarded as one of our "secret" machines the "Hendon" has now been "released," and on Tuesday of last week, July 20, a demonstration took place at Cricklewood, at which a number of representatives of the press, as well as certain foreign Air Attaches, and others interested, were present.
   The "Hendon" was piloted by Handley Page's chief test pilot, Capt. Wilcockson, who took up a number of passengers from among the visitors present. The machine certainly flew remarkably slowly when the wing slots were open, and the pilot put it through a number of evolutions to show the effectiveness of the lateral control. His flat turns were particularly impressive. It was noticed that in taking off with slots open and flaps down, the "Hendon" climbed at a very steep angle, but apparently the rate of climb was not out of the ordinary, and in point of fact, we are informed that the rate of climb is better with slots closed, although the angle of climb is then not so good.
   When flying slowly the machine was approximately on an even keel, which was also its attitude when descending along a flight path steeply inclined to the horizontal. This is, of course, explained by the fitting of trailing edge flaps interconnected with the slots, since the effect of the flaps is virtually to increase not only the camber, but angle which the wing chord forms with the centre line of the machine. In descending at an angle which would certainly correspond to a stalled condition on a normal machine, the "Hendon" appeared to be under perfect lateral control, and whatever may be the merits of the slotted wing for giving increased lift (and this is a subject upon which opinions seem to differ very considerably), there cannot, we think, be any question that the slot-cum-flap lateral control does very definitely provide that extra safety in the stalled condition which results from ample lateral control.
   The diagram printed on p. 460 shows how the slots and flaps on the "Hendon" are arranged. The auxiliary aerofoil, which is of the single surface (i.e., flat sheet) type, is divided into a long centre portion and two shorter end portions. The centre portion may be described as providing a "lift slot," while the end portions are "control slots." By this is meant that the central slot and the central trailing edge flap, used in conjunction, give extra lift, while the end slots, the auxiliary aerofoils of which are inter-connected with short trailing edge flaps, are, of course, used to obtain powerful lateral control.
   In flight with lift slot partly open, the two aerofoils of the control slots are slightly less open than the main slot, and with the lateral control "full on," one control slot closes altogether, while the other opens fully, i.e., its aerofoil moves out level with the lift slot aerofoil. In taking off and landing when maximum lift is required, all slots are open and all flaps down, although the control flaps still retain a further movement for lateral control, and in this condition lateral control is obtained mainly by raising the flap and closing the slot on the rising side, thus decreasing the lift on that side. We understand that in a more recent arrangement an even more effective control action is obtained, but even with the present arrangement there can be no doubt that very powerful lateral control is obtained, and we understand that it is claimed that this is not accompanied by the usual necessity for a very powerful rudder, as the forces on the two sides are approximately balanced as regards yawing moments.