M.Hardy. Gliders & Sailplanes of the world

Slingsby HP-14C

  During the 1960s the traditional wood and fabric construction for sailplanes was increasingly challenged in Europe by glassfibre and to a lesser extent by metal construction, and so Slingsby, to remain competitive, acquired ДальшеMore>>> a licence to build the American Bryan HP-14 all-metal high performance single-seater, designed by R. E. Schreder, while their own first all-metal design, the T53, was on the drawing board. All-metal construction rather than glassfibre was chosen because it involved considerably fewer man-hours for assembly than wood, and metal was easier and less critical to repair than glassfibre. The Bryan HP-14, of aluminium construction, made its first flight in prototype form on 24 June 1966 with a 'butterfly'-type V-tail of 90° included angle, and this aircraft, flown by its designer, won the 1966 US National Soaring Championships. The HP-14T version with a conventional T-tail first flew on 19 May 1968, and over 100 of both versions were built by Bryan Aircraft Inc and amateur constructors supplied by them with kits for the HP-14, which had all skins, ribs and bulkheads formed and welded parts welded ready for assembly. The first of two Slingsby-built HP-14s was completed and flown in May 1967, but the type was redesigned by Slingsby's to suit British conditions and airworthiness requirements, the revised version being known as the HP-14C. The V-tail was replaced by a conventional fin and rudder with a fairly low-set all-moving tailplane, the wing span was increased to 18m (59ft 0 1/2 in) and the cantilever shoulder wings moved back 6in to give a wider cg range and a roomier cockpit, the structure was redesigned to meet ARB requirements and a tail braking parachute was fitted. The original rack-and-pinion flap operating mechanism was replaced by a pneumatic system with two jacks to lower the flaps to 90°, when they serve as air brakes; on the US-built HP-14s the flaps could be hydraulically operated if the customer desired. The HP-14C prototype first flew on 11 April 1968 and the three HP-14Cs were built by Slingsby, two for the British team at the 1968 World Championships in Poland, and one for the Spanish team, but these were all that could be built before the firm's main factory area was destroyed by fire on 18 November 1968. Five more under construction were not completed due to loss of jigs in the fire, and were later stored, but six HP-14C kits were supplied to Australia and one to Finland, one more being built from a kit by W. J. Provins of Scarborough. Another HP-14 built by Southdown Aero Services Ltd of Lasham had a V-tail of 50% greater span than the American version, and was later sold to the USA as N8838, where it was converted into an HP-14T with a T-tail.
  The Bryan HP-14 has an aluminium wing structure, with plain aluminium ailerons, and no spoilers are fitted. The fuselage is an aluminium monocoque, with a steel tube frame around the cockpit, and there is a manually retractable monowheel and a fixed steerable tailwheel; the monowheel has a hydraulic shock-absorber and brake. The pilot sits in a semi-reclining position under a long Plexiglas canopy consisting of two fixed pieces and a hinged section; a 90-channel transceiver and an oxygen system can be fitted.


Data: HP-14C
Span: 59 ft 0 1/2 in
Length: 23 ft 10 1/2 in
Height: 3 ft 11 in
Wing area: 146.2 sqft
Aspect ratio: 23.9
Empty weight: 639 lb
Max weight: 840 lb
Max speed: 135 mph (in smooth air)
Min sinking speed: 1.64 ft/sec at 52 mph
Best glide ratio: 44:1 at 60 mph



Bryan HP-15

  One of America's foremost sailplane designers and pilots is Richard E. Schreder whose HP-8, built and flown by himself, won the US National Championships in 1958 and 1960; this was followed by the single-seat high performance HP-10, produced in kit form by Helisoar Aircraft Inc of Danbury, Connecticut, by the HP-11 and HP-11 A competition single-seaters, the HP-11 being placed third in the 1963 World Championships, and the Standard Class HP-12 derived from the HP-11. The HP-11, HP-11A and HP-12 were built by Airmate at Toledo, Ohio - a company formed by Mr Schreder - and his next design, the HP-14 high performance single-seater, was produced in kit form by Bryan Aircraft Inc of Bryan, Ohio, which firm had also produced plans of the HP-11A for homebuilders; the HP-14 was also licence-built in modified form by Slingsby Sailplanes Ltd as the HP-14C. The 1970 World Championships were held at Marfa in Texas and Schreder designed the HP-15 for this contest to take full advantage of the high-lift Texan thermals; it was also intended to meet the new Standard Class rules which had come into force in 1969 allowing a retractable undercarriage and fixed-hinge flaps on 15m span sailplanes. A very high aspect ratio of 33 and (for a sailplane) the high wing loading of 7.99 lb/sq ft were chosen to ensure high speed performance, and the HP-15 was of all-metal construction. The two-spar wings had only three ribs in each, plastic foam covered by rolled-to-contour metal skins and with plastic leading edges filling the intervening spaces; the ailerons droop in conjunction with the metal flaps. The fuselage is an aluminium monocoque and incorporates an aluminium butterfly tail with an included angle of 90°; this V-tail was a characteristic of previous Schreder designs. The retractable monowheel has hydraulic shock-absorber struts and the tailwheel is steerable. Flight trials of the HP-15 - it first flew in the summer of 1969 - showed it to have difficult handling characteristics and it did not, in the end, fly in the 1970 World Championships nor did it go into production.


Data: HP-15
Span: 49 ft 2 1/2 in
Length: 23 ft 2 1/2 in
Wing area: 75 sq ft
Aspect ratio: 33.0
Empty weight: 331 Ib
Max weight: 600 lb
Max speed: 150 mph (in smooth air)
Min sinking speed: 1.6 ft/sec at 45 mph
Best glide ratio: 45:1 at 54.5 mph



Bryan HP-18

  Schreder's latest design to appear is the Standard Class HP-18, which made its first flight in 1975; it is designed for sale in kit form for homebuilt construction and assembly, and about 170 had been built or were under construction by early 1979. It is of all-metal construction with machined aluminium spars for the cantilever shoulder wing and precut hard foam wing ribs spaced at 10cm intervals; the HP-18A differs in having carbon-fibre spars but has similar wing rib construction. Camber-changing flaps and ailerons occupy the entire trailing edge, and up to 200lb of water ballast can be carried. The design also incorporates certain improvements over the Standard Class RS-15 to which it is generally similar, such as new wing tips, a removable tailwheel, better gap seals and improved streamlining. The HP-18 has a slightly longer fuselage than the RS-15, with a circular instead of oval section, and this is supplied as a pre-formed Kevlar pod, aluminium rear fuselage and the V-tail; the pilot sits under a two-piece flush canopy. A retractable Tost monowheel with a mechanically-expanding brake is supplemented by a steerable tailwheel. One HP-18, C-GOIY, has been modified by its Canadian builders Don Band and Peter Masak to have winglets of glassfibre and balsa and Wortmann FX-60-126 section at the wing tips.


Data: HP-18A
Span: 49 ft 2 1/2 in
Length: 23 ft 6 in
Height: 4 ft 0 in
Wing area: 114.7 sq ft
Aspect ratio: 21.1
Empty weight: 420 lb
Max weight: 920 lb
Max speed: 150 mph (in smooth air)
Max aero-tow speed: 120 mph
Min sinking speed: 1.70 ft/sec at 45 mph
Best glide ratio: 40:1



Bryan RS-15

  To meet the Standard Class specifications of OSTIV - the Organisation Scientifique et Technique Internationale du Vol a Voile - Mr Schreder designed the 15m span RS-15 single-seater, which first flew in 1973 and is especially intended for simple and rapid assembly by homebuilders; it is licensed in the amateur-built Experimental category. No jigs are required, and most major components are prefabricated, thus reducing assembly time for a builder with no more than average mechanical aptitude to approximately 500 man-hours. The cantilever shoulder wings are all-metal except for polyurethane foam plastic ribs spaced at 4in intervals. The main-wing spar caps are machined from aluminium plate and up to 200lb of water ballast is carried inside the wing box spars. Plain ailerons are featured, and these can be linked to the optional trailing edge flaps/air brakes, which are of aluminium sheet bonded to foam ribs. The monocoque fuselage is built in two main parts: a prefabricated glassfibre forward pod, complete with bulkheads, floorboards and a moulded pilot's seat, and a 6in diameter tail boom of aluminium tube with an all-metal V-tail which can be folded upwards for towing or storage. The retractable monowheel has a hydraulic shock-absorber and brake, and there is a fixed steerable
tailwheel, also with a shock-absorber.


Data: RS-15
Span: 49 ft 2 1/2 in
Length: 22 ft 0 in
Height: 3 ft 10 in
Wing area: 113 sqft
Aspect ratio: 21.4
Empty weight: 440 lb
Max weight: 940 lb
Max speed: 150 mph (in smooth air)
Max aero-tow speed: 120 mph
Min sinking speed: 2.10 ft/sec at 50 mph
Best glide ratio: 38:1