The Addyman Zephyr was a one-off, single-seat sailplane designed and built by Erik Addyman in the UK for his own use in the 1930s.

Design

Erik Addyman designed and built the single-seat Zephyr, his first design, in 1933. It was intended as a light wind sailplane, combining a wing of modest aspect ratio with a nacelle cockpit and an open truss girder fuselage of the kind more common on primary gliders. It was a wooden-structured, largely fabric-covered aircraft. The two- spar wing had a straight leading edge and constant

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

out to a little over half span, where the trailing edges of the ailerons, hinged at a slight angle to the spar, curved inwards to the wingtips. It was braced from above with pairs of wires from the spars to a central, inverted V-strut pylon and below by wires to the lower nacelle

longerons In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

. There were no flaps or air brakes. The central wing rib was continued rearward with the upper member of the open, flat, converging

Warren girder A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or s ...

fuselage, whose lower member joined the keel of the

plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

- and fabric-covered nacelle just aft of the wing trailing edge. This placed the open single cockpit just forward of the wing leading edge. A central keel skid formed the main

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

, with assistance from a tail bumper. A narrow-span, triangular tailplane, wire braced above and below, carried longer-span elevators with rounded tips and a cut-out for the deep, rounded rudder hinged to small, triangular fin. The Zephyr flew for the first time in 1933.

Operational history

Only one Zephyr was built. Based at Harrogate, where Addyman was honorary secretary of the Aircraft Club, it was often launched with a tow from a horse. He flew it from many fields in central and north-western England up to the early part of World War II; from 1940 there was a government ban on recreational glider flying. The Zephyr seems not to have flown again, though substantial parts of it still (2010) exist in store.

Specifications

References

{{reflist, refs= {{cite book , title= British Gliders and Sailplanes, last=Ellison, first=Norman, year=1971, publisher=A & C Black Ltd, location=London , isbn=978-0-7136-1189-2, page=79 {{cite book , title= Wrecks & Relics, last=Ellis, first=Ken, year=2010, edition=22, publisher=Crecy , location=Manchester , isbn=978-0-85979-150-2, page=265 {{cite journal, date=March 1934 , title=Horse-towed flight , journal=Sailing and Gliding , volume=5 , issue=3 , pages=34 , url=http://www.lakesgc.co.uk/mainwebpages/Sailplane%20&%20Glider%201930%20-%201955/volume%205%20No.%203%20Mar%201934.pdf , url-status=dead , archive-url=https://web.archive.org/web/20110930180132/http://www.lakesgc.co.uk/mainwebpages/Sailplane%20%26%20Glider%201930%20-%201955/volume%205%20No.%203%20Mar%201934.pdf , archive-date=2011-09-30 {{cite journal, date=March 1933 , title=News from the Clubs - a light wind sailplane , journal=Sailing and Gliding , volume=4 , issue=8 , pages=93 , url=http://www.lakesgc.co.uk/mainwebpages/Sailplane%20&%20Glider%201930%20-%201955/volume%204%20No.%208%20Apr%2028%201933.pdf , url-status=dead , archive-url=https://web.archive.org/web/20110930180017/http://www.lakesgc.co.uk/mainwebpages/Sailplane%20%26%20Glider%201930%20-%201955/volume%204%20No.%208%20Apr%2028%201933.pdf , archive-date=2011-09-30 1930s British sailplanes Aircraft first flown in 1933