Schreder HP-18 explained

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.^[1]

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^[1] 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

• EAA Airventure Museum, Oshkosh, Wisconsin^[2]
• National Soaring Museum, Elmira, New York^[3]
• US Southwest Soaring Museum, Moriarty, New Mexico^[4]

References

• Schreder Designs webpage
• R Johnson, A Flight Test Evaluation of the HP-18W Sailplane, Soaring, July 2003

External links

• HP-18 Reference Info Link

Notes and References

1. Web site: HP-18 HP Aircraft, LLC. 2008-07-24. Activate Media. 2006. dead. https://web.archive.org/web/20080303025015/http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=165. 2008-03-03.
2. Web site: Bryan/Harris HP-18 Sailplane. 28 March 2011. dead. https://web.archive.org/web/20110719095807/http://museum.eaa.org/collection/aircraft/Bryan_Harris%20HP-18%20Sailplane.asp#TopOfPage. 19 July 2011.
3. Web site: Sailplanes in Our Collection. 26 February 2011. National Soaring Museum. 2011. May 16, 2011. https://web.archive.org/web/20110516142717/http://www.soaringmuseum.org/collection.html. dead.
4. Web site: Sailplanes, Hang Gliders & Motor Gliders. 26 May 2011. . 2010.