HP-18
An HP-18 dis-assembled prior to display at the Paradive Flight Gallery in Habonim
Role Club (formerly 15 metre) class Sailplane
Manufacturer Homebuilt
Designer Richard Schreder
Number built 180 kits sold[1]

The HP-18 is a Richard Schreder-designed metal Racing Class sailplane that was offered as a kit for homebuilding during the 1970s and 1980s.[2]

Design and development

The HP-18 is a flapped (15-meter) sailplane featuring a V-tail and 90-degree flaps for glidepath control. The fuselage is composed of a prefabricated composite forward fuselage and a semi-monocoque aft fuselage, and features steeply reclined seating and a side-stick controller[2] although modifications using a conventional stick have been made.

Major features:

  • Very low cockpit with reclining seating position
  • Sidestick (changed to conventional stick by some homebuilders)
  • Two-piece canopy (changed to single piece forward opening by some homebuilders)
  • V-tail that folds upwards for easy storage
  • Wing structure composed of spars with caps pre-machined from solid aluminium plate and aluminium wing skins bonded to closely spaced foam ribs
  • Fiberglass fuselage pod, wing tip skids and tail fairings
  • Aluminium tail cone
  • Winglets added by some homebuilders
  • Water ballast carried inside the hollow aluminium wing spars
  • Typical Schreder trailing edge flaps/airbrakes partially interconnected with the ailerons

Variants

As most homebuilts, the HP-18 has been constructed with many variations in detail. Perhaps the most significant version is the Super HP-18 developed by Canadians Ed Hollestelle and Udo Rumpf, which features a modified wing airfoil, winglets, a front-hinged canopy, conventional control stick and higher ballast capacity.

Aircraft on display

Specifications

General characteristics

  • Crew: One pilot
  • Length: 23 ft 2.4 in (7.07 m)
  • Wingspan: 49 ft 2 in (15.00 m)
  • Wing area: 113 sq ft (10.5 m2)
  • Aspect ratio: 21.4
  • Empty weight: 470 lb (213 kg)
  • Gross weight: 970 lb (446 kg)

Performance

  • Maximum speed: 150 mph (240 km/h, 130 kn)
  • Maximum glide ratio: 38
  • Rate of sink: 126 ft/min (0.60 m/s)

References

  1. ↑ Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 23. Soaring Society of America, November 1983. USPS 499-920
  2. 1 2 Activate Media (2006). "HP-18 HP Aircraft, LLC". Archived from the original on March 3, 2008. Retrieved July 24, 2008.
  3. ↑ "Bryan/Harris HP-18 Sailplane". Archived from the original on July 19, 2011. Retrieved March 28, 2011.
  4. ↑ National Soaring Museum (2011). "Sailplanes in Our Collection". Archived from the original on May 16, 2011. Retrieved February 26, 2011.
  5. ↑ US Southwest Soaring Museum (2010). "Sailplanes, Hang Gliders & Motor Gliders". Retrieved May 26, 2011.
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