Building the Little Dragon
Background
In 1950, the magazine Model Airplane News published a two part article describing a simple 0.06 cuin engine for home construction called the Little Dragon. The designer and author was Roy Clough Jr. Roy appears to have been the man called on when something out of the ordinary was required; engines, free-flight helicopters and ducted-fan designs, Roy did them all. His concept for the project was that is should be:
"..a project any amateur machinist can tackle with full confidence of good results. It does not require any special tools, special talents, or extreme precision. A large part of the total time spent in developing the design was devoted to eliminating awkward machining jobs, delicate operations, and tricky assemblies. If the reader owns a small lathe and can center a piece of stock with 1/64", he need have no qualms about being able to turn out the job."
Roy's design was the basis for a number of derivative designs. Taking the Little Dragon as his starting point, Tom Crompton developed a series of simple glow and diesel engines which he called the EZE. The appeared in the English magazine Model Engine World. Further detail on these is available on the EZE Construction Pages of this web site.
Having been asked to develop a simple engine for home construction on minimal equipment for Model Engine Builder magazine, I began examining the features other designers had adopted in this same quest. Naturally, the LD was one of the engines considered. Knowing that readers of the Model Engine News Web Magazine would find descriptions of the types examined of interest, my thoughts were collected and placed on a page titled Design for Beginners page.
Although I had no pre-existing bias against the design, as I began to look closely at it, I found a number of aspects that I questioned in a beginners' engine design (click here to read what I objected to). Having published this, I found my criticisms of the design were weighing heavily on my mind, although I did not retract from them. There was obviously only one answer: build an example of the engine as close as possible to the published plans and see if the things I envisioned as problems were real of imagined.
The pages referenced show the machining of all components in considerable detail. They were built from my own CAD plans drawn to the original design. Registered Members of Model Engine News (ie, those who have bought the MEN Only CD) may download these plans from the Members Only Area.