The HP-16 involved major changes in Schreder’s HP-15 design, with a different wing similar to the RS-15 of much lower aspect ratio and grater area. The aluminum wing skins are bonded to foam ribs, including rivet use and construction time. The HP-16 retains the very effective 90 degrees Schreder flaps. One belongs to the National Soaring Museum. Structure: all-metal except for foam wing ribs.
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 high aspect ratio of 33 and 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.
The wing was later retired and the fuselage re-winged.
Wing span: 15.0 m / 49 ft 2.5 in Wing area: 6.97 sq.m / 72 sq.ft Wing section: Schreder 69-180 Aspect ratio: 33 Length: 7.07 m / 23 ft 2.5 in Empty Weight: 150 kg / 330 lb Payload: 122 kg / 270 lb Gross Weight: 272 kg / 600 lb Wing Load: 39.02 kg/sq.m / 8 lb/sq.ft Water Ballast: 0 Max speed: 150 mph / 130 kt / 241 km/h (in smooth air) Stalling speed: 30 kt / 56 km/h Max rough air speed: 98.5 kt / 183 km/h Best glide ratio: 45:1 at 54.5 mph / 47.5 kt / 88 km/h MinSink: 0.49 m/s / 1.6 fps / 0.95 kt at 45 mph / 39 kt / 72 km/h No. Built: 1 Seats: 1 Structure: Metal
The all metal HP-14 was developed from the HP-13 which was essentially a HP-11 fuselage with the Wortmann airfoil used on the HP-12, with extended span. That wing was later mated to an improved fuselage to become the HP-14. The HP14 used lower wing loading and reduced aspect ratio in an attempt to maximize performance in weak conditions. 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 HP-14 features a folding V-tail and 90-degree flaps for glidepath control. 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 Richard Schreder, won the 1966 US National Soaring Championships.
HP-14 at 426 kph – pilot John de Jong
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.
More than 40 of all versions were built in the U.S. and by Slingsby in Great Britain. The ship has appeared with all three tail styles: the original had the Schreder V- tail, Slingsby produced the HP14C version with 18 m. wing and conventional tail, and the HP14T version used the C wing with a T-tail. 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 Slingsby HP-14Cs are ATC’d. Slingsby, to remain competitive, acquired 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.
Slingsby HP-14C
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 0.5in) 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 HP14C adopted a rechargeable pneumatic system to ease aerodynamic operating loads at high speed. 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.
Slingsby HP-14C
The HP-14 was produced in kit form by Bryan Aircraft Inc of Bryan, Ohio.
As with many homebuilts, a number of builders have made design changes to their ships. In some cases these have been substantial. Andre Krutchkoff built his SHP-1 with his own design of fuselage with T-tail. Paul Bikle produced a modified HP14 (the T-6) with a 17.37 m./ 57 ft. span wing and control system modifications. Otto Zauner constructed an 18 m. model (called the Zauner OZ- 4) which has been modified substantially to have tip extensions with winglets to give a span of 19.2 m. / 63 ft, and a gross weight of 386 kg./ 850 lb.
HP-14C Span: 18.0 m / 59 ft 0.5 in Length: 7.28 m / 23 ft 10.5 in Height: 1.19 m / 3 ft 11 in Wing area: 13.58 sq.m / 146.2 sqft Wing section: Wortmann FX-61-163 Aspect ratio: 23.9 Empty weight: 290 kg / 639 lb Max weight: 381 kg / 840 lb Water ballast: None Max wing loading: 28.1 kg/sq.m / 5.75 Ilb/sq.ft Max speed: 135 mph / 117 kt / 217 km/h (in smooth air) Stalling speed: 29.5 kt / 55 km/h Max rough air speed: 104 kt / 193 km/h Min sinking speed: 0.5 m/sec / 1.64 ft/sec at 52 mph / 45.5 kt / 84 km/h Best glide ratio: 44:1 at 60 mph / 52 kt / 96 km/h
The all metal HP-12A is a modification of the original HP-12 of R. E. Schreder, which was a one-of-a-kind built to fly in the 1965 World Championships at South Cerney, England.
The Standard Class HP-12 was derived from the HP-11. The HP-11, HP-11 A and HP-12 were built by Airmate at Toledo, Ohio-a company formed by Mr Schreder.
The all metal HP-11 was produced in 1962 in time for the 1962 U.S. Nationals, in which Schreder placed third and made the longest flight, 754.8 km/ 469 miles; he later placed third in the Open Class at the 1963 World Championship at Junin, Argentina.
The HP11A, an improved version, has a retractable wheel. Some significant modifications were made in a number of the kit- built HP-11s including, for example, the Kohler Alpha which mated a new fuselage on to the wings of an HP-11. Michael Bowlus used the tail of an HP-18 and the wings of an HP-11, reduced to 15 m., to develop his BZ-1, which first flew in 1984.
One HP-11 belongs to the National Soaring Museum.
One of America’s sailplane designers and pilots is Richard E. Schreder who built the HP-10, and 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 Richard E. Schreder.
Bryan Aircraft Inc of Bryan, Ohio, also produced plans of the HP-11 A for homebuilders.
The all-metal V-tail HP-10 was flown by designer R. E. Schreder in the 1961 U.S. Nationals, winning the Stroukoff Trophy for a 57 kph/ 31 kt/ 35.5 mph 229 km/ 142 miles Goal & Return flight.
The HP-10 was modified by Steve du Pont.
Helisoar bought the production rights and produced the HP-10 in kit form. Some ships were modified with fiberglass Hoerner wingtips made available by Helisoar.
The R. E. Schreder designed all metal HP-9 was intended to fly in the Standard Class at the 1960 World Championships, but was not completed in time. It has an all-moving horizontal tail, retractable wheel, airbrakes and Fowler flaps which increase the wing area to 13.35 sq.m/ 143.7 sq.ft when extended, reducing the sink to 0.64 m/s/ 2.11 fps./ 1.25 kt. @ 76 kph/ 41 kt/ 47 mph.
R. E. Schreder built the improved all-metal HP-8 in 1958 and won the Nationals with it in that year again in 1960. He set world records with it in all three speed categories in 1959, and two of these were raised again by the same ship flown by George Moffat. The solo example belongs to the National Soaring Museum.
R. E. Schreder’s first sailplane, the HP (for High Performance) 7, first flew in 1957 and was destroyed in an aerotowing accident right after the 1957 U.S. Nationals.
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