The Model Engine World EZE series engines

(Last Update February 18, 2002)


The EZE series of engines evolved from a design called the "Little Dragon" by Roy L Clough Jr, which originally appeared in Model Airplane News for October and November, 1950. Their developer, Tom Crompton, has evolved the basic design over many years and more than thirty engines with the goals of achieving an engine that could be built with minimal equipment by inexperienced model engineers, yet would start easily, handle well, provide reliable power for small models and last a couple of flying seasons without employing exotic materials, or material treatments.

A photograph showing the evolution of the series appeared on the back cover of the British publication Model Engine World of January, 1997. John Goodall, then editor of MEW, asked Tom to share his work with the readers by presenting plans and building instructions for one of the series. Judging from the readership response as evidenced from the "letters to the editor" column, there is significant interest and appreciation of this type of design, so the first article has been followed by others in the series. It is worth noting that each engine is completely described in a single issue - a fact perhaps appreciated by the faster workers. To date, the series comprises:

  • EZE-1: MEW Nov 1998, Rear Rotary Valve (RRV) induction, glow plug ignition.
  • EZE-2: MEW Jan 1999, Front Rotary Valve (FRV), compression ignition (aka "diesel").
  • EZE-3: MEW Sep/Oct 1999, Side Port Induction, compression ingnition.
  • EZE-RV: (no published plans) Reed valve conversion of the EZE-1.

The engines share common parts and are totally fabricated (ie, there are no castings required). Like the "Little Dragon" from MAN in the 1950's, their main stationary components are machined from 3/4" square aluminum bar stock, requiring only turning and drilling operations, although minimal milling facilities, such as a vertical slide for the lathe saddle, would make life simpler for some operations. Cylinder liners and crankshaft are steel, with cast iron used for the piston and contra-piston (diesel verson).

Depending on the builder's working pace and experience, an example can be completed in a week or two of evenings. Complexity wise, the design is a step up from Roger Schroeder's "Simple Single" design that appeared in SIC, issues 49 through 54 (these can be ordered from the SIC Web site) . This RRV engine also employs a crankcase machined from 3/4" square bar stock, but uses a Cox .049 Cylinder/piston assembly, virtually assuring the first time builder of a long lasting, strong running engine. Tom's designs may well be considered the next step from Roger's in that they give the builder the total "built it all myself" satisfaction.

My research as shown that Roy Clough's design has proven very popular and durable over the past half century. From Scott Bashiers, writing in Engine Collectors Journal, issues 114 (12/94) and 117 (6/95), we learn that the basic design was reworked by John R Walker who was using it as a high school machine-shop project in 1956. He subsequently wrote three books titled Projects for Metals with his FRV adaptation (called the "Shrimp") appearing in volume I. All ECJ back issues are available from Tim Dannels at the Model Museum. Back issues of MEW are available from John Goodall in the UK. Currently, MEW appears quarterly under the new editorship of Mr Andrew Naham. Contact Andrew, or visit his website for postal rates to your location.