Townend ring
Encyclopedia
Chord (aircraft)
In aeronautics, chord refers to the imaginary straight line joining the trailing edge and the center of curvature of the leading edge of the cross-section of an airfoil...
cowling ring fitted around the cylinders of an aircraft radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
to reduce drag and improve cooling.
Development
The Townend ring was the invention of Dr. Hubert Townend of the BritishUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
National Physical Laboratory in 1929. Patents were supported by Boulton & Paul Ltd
Boulton & Paul Ltd
Boulton & Paul was a British general manufacturer from Norwich that became involved in aircraft manufacture.Jeld Wen Inc, bought Boulton & Paul Boulton & Paul was a British general manufacturer from Norwich that became involved in aircraft manufacture.Jeld Wen Inc, bought Boulton & Paul Boulton &...
in 1929. In the United States it was often called a "drag ring". It caused a reduction in the drag of radial engines and was widely used in high-speed designs of 1930-1935 before the long-chord NACA cowling
NACA cowling
The NACA cowling is a type of aerodynamic fairing used to streamline radial engines for use on airplanes and developed by the National Advisory Committee for Aeronautics in 1927...
came into general use. It was also said to generate forward thrust from the expansion of the air as it passed over the engine, adding 10 to 15 mph to the aircraft's top speed.
Examples of aeroplanes with Townend rings were the Douglas O-38
Douglas O-38
-References:*The complete Encyclopedia of World Aircraft Editors: Paul Eden & Soph Moeng, , 1152 pp.-External links:...
, Vickers Wellesley
Vickers Wellesley
The Vickers Wellesley was a British 1930s light bomber built by Vickers-Armstrongs at Brooklands near Weybridge, Surrey, for the Royal Air Force...
, the Westland Wallace
Westland Wallace
The Westland Wallace was a British two-seat, general-purpose biplane of the Royal Air Force, developed by Westland as a follow-on to their successful Wapiti. As the last of the inter-war general purpose biplanes, it was used by a number of frontline and Auxiliary Air Force Squadrons...
and the Gloster Gauntlet
Gloster Gauntlet
-See also:-References:NotesBibliography* Crawford, Alex. Bristol Bulldog, Gloster Gauntlet. Redbourn, UK: Mushroom Model Publications, 2005. ISBN 83-89450-04-6....
. Early claims portrayed it as a superior design to the NACA cowling, but later comparisons proved aircraft performance worse when using a Townend ring at airspeeds above 250 mph.