FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1957
1957 - 0541.PDF
Like a fencer's mask, P.I A number WG 760 wears its strange intake guard on a sunny day at Warton. Ranged alongside is WG 763 occupying as they do positions appropriate to those of an unsweptwing (i.e., parallel to the transverse axis) they straddle the tips of the wing from what might be termed the leading to the trailingedges. To a considerable extent, therefore, aileron loads introduce pure bending in the wing, substantially reducing torsional defkc-tions and consequent aileron reversal. Although the ailerons were originally horn-balanced they will be inset in future wings. In order to achieve optimum flow and isobar patterns over thewing English Electric incorporated fore-and-aft slots in positions akin to wing fences. These "saw-cuts," which were developed onthe S.B.5, give less drag than fences and are not so susceptible to damage. A single large section of flap occupies each trailing edge fromthe fuselage to near the inner end of the aileron. On the P.I A an area-increasing pattern has been adopted, and each flap sectionmoves out parallel to the longitudinal axis of the aircraft; were the flaps to mort along the chord-line of the wing their inner endswould immediately foul the fuselage. To British Messier went the onerous task of designing theundercarriage. The steerable nose gear of the P.I A is very short and turns through 90 deg as it retracts forward to lie flat under theintake ducting. The main legs are attached roughly in the geometric centre of each mainplane and retract outwards.Consideration of the relative inclinations of the hinge axes and the main-wheels explains why the latter turn through some 60 deg inorder to lie within the thin wing. Accommodation of the main units within the wing was accomplished only by employing muchsteel in the leg fork and by choosing a tyre pressure of 280 lb/sq in. A unique feature of the arrangement is that the retracted wheelsare enclosed by large doors hinged inboard of the wheel wells, i.e. on the same side of the well as the leg. The arrangement has giventhe P.I a very wide track and excellent stability on the ground— although, short of employing a variable-incidence wing, it isdoubtful if the maximum desirable ground angle can be employed to permit the optimum lift coefficient of the wings to be realized.Tyres, wheels and Maxaret-equipped brakes are by Dunlop. Selected powerplant was the Armstrong Siddeley Sapphire,probably with a dry rating of about 7,500 lb thrust. Martin-Baker supplied the Mk 4 ejection seat, Irvin the braking parachute andmuch equipment came from the English Electric Group. The three P.I A airframes were constructed at Preston in productionjigging. The first machine, which bears the serial number WG 760, flew from Boscombe on August 4, 1954, in the hands ofMr. Beamont. Since that date WG 760 and its sister ship WG 763 (of whichmore anon) have completed more than 500 successful flights. The two prototypes have been flown by all kinds of pilots fromthe Services and elsewhere, who have found them completely straightforward flying machines presenting no special conversionproblems. Pilots of the Central Fighter Establishment have re- ported very favourably on its behaviour. On its first flight WG 760 exceeded the speed of sound withoutthe pilot being aware of the fact. A few days afterwards data- reduction on a later flight showed that the machine had gonesupersonic in a climb, although position-error in the airspeed system had caused the Mach-meter to record a maximum of 0.95.No special effects had manifested themselves, and Beamont, who was flying, was surprised when given the news. Notwithstand-ing a claim promoted in respect of the French Gerfaut, it seems that this was the first occasion on which a conventional fighterexceeded the speed of sound without diving or employing reheat (afterburning) or rocket boost. From October 1954 supersonicflying was conducted as a matter of course. The second P.I A, WG 763, took to the air in July 1955 anddiffers from its data-gathering predecessor in having two 30mm Aden guns mounted in the forward fuselage, firing from blast tubeshigh on each side of the nose. It also carries additional operational equipment. Gun-firing tests in special rigs began at the company'sexperimental base at Warton in 1953. Owing to the fact that the muzzles of the guns are situated well back from the engine intakeno surging or compressor-stalling has been experienced in air- firing trials. The latter began more than a year ago and haveranged over a very wide band of speeds (including supersonic) and altitudes. From 1954 flight trials with the two P.I As have been backedup by the most extensive tunnel testing ever conducted on a British aeroplane, and by a tremendous programme of data re-cording and electronic computing with which every facet of the behaviour of the aircraft has been fully explored. One of theresults of this may well be that the design has been made to offer an extremely stable platform for the launching of weapons, with-out the need for recourse to auto-stabilization. This statement is not meant to imply that auto-stabilization is not fitted, but itunderlines the difference between the inherently rock-steady flight of the P.I and the rigidly controlled trajectory of several trans-atlantic fighters which are forced to rely on auto-stabilization about two or three axes in order to fly at all. Few would be bold enough to deny that the question of fighterarmament is still somewhat in the melting pot. While all are agreed that, for most purposes, the ultimate weapon for such air-craft is the guided air-to-air missile, it is prudent to retain at least the capacity for operating with conventional weapons. Thus,although there is no doubt that guided weapons will form the main armament of the definitive P.I fighter, the aircraft has alsobeen planned to carry guns, and, no doubt, spin-stabilized rockets. It would be logical for special provision to have been made forpermitting the type of armament carried to be changed rapidly and easily during field service. All the equipment associated withthe various types of armament is likely to be available in package form within the time scale of the aircraft, thus fulfilling a majorrequirement of the weapon-system doctrine. Most of the flying with the two P.I A prototypes has beencarried out from the company's, airfield at Warton. Both air- craft have, however, used smaller airfields, and it is known thatthe eventual production aeroplane will be well suited to the types of airfield from which it will be required to operate (i.e., the presentR.A.F. or NATO operating platform. One of the P.lAs has made a number of G.C.A. landings. Operating largely over the Irish Sea (Flight, March 1) super-sonic flights have been made at altitudes down to well below 10,000ft (the startling minimum may not be quoted), and virtuallythe whole flight envelope of the P.I A must now have been explored. English Electric P.1B Two Rolls-Royce Avon
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
