Model Engine Plans for Home Construction

Model Engine Plans for Home Construction

With this thread, I'm creating an area on this website where plans for model engines which can be constructed at home may be found. With the invaluable assistance of my good friend Ken Croft, I've already been privileged to make the Motor Boys Planbook and the Members-Only Plan Book available elsewhere on the site, and the plans for the Weaver 1 cc diesel also appear here in a separate article.

This new page will confine itself to plans for engines not captured in any of the above pages. For convenience in locating a particular plan, the entries will appear here in alphabetical order rather than in the order in which they were received. 

Any reader having access to hi-res (i.e., legible) plans not included either here or elsewhere on this website is hereby cordially invited to submit them to me for publication along with a clear and representative photograph of a complete example of the engine in question and any construction guidance which may be available. As always, I reserve the right to confirm the suitability for publication of any material submitted and to write my own commentary on the engines represented by the plans. 

I also remain open to the submission of additional articles on various aspects of the home construction of model engines in general. If accepted for publication, any such submissions will be added to the Technical Topics pages on this website. Once again, I reserve the right to edit any such submissions.

The following is an alphabetical listing of the plans which presently appear here. More will be added as additional plans are received.

Holly Buddy 2.5 cc diesel

Sugden Special 2.5 cc diesel

Details of each of these engines follow below.

Holly Buddy

We'll start off with the Holly Buddy, a really nice-looking radially-mounted 2.5 cc diesel that has been very cleverly designed to be easily built entirely without castings. Those of us who are familiar with 1950's rock 'n roll icons will appreciate the play on words in the engine's name!

This engine was designed by Ed Holly, who published a photographic essay on its construction on the Home Model Engine Machinist website. That essay remains available online through the link provided. Here I'm making Ed's own pdf commentary available along with the plans for the engine. Hopefully a few of you will have a go at building your own examples! Click here to bring up Ed's commentary along with the plans for the engine.

Designer Ed Holly was kind enough to send an example of this engine to my good mate Maris Dislers. A detailed review and test of the engine appeared in issue no. 980 (January 2019) of "AeroModeller" magazine. Maris found that while the Buddy is no powerhouse by present-day standards, its general handling and running qualities were very good indeed. In his view it compared quite favorably with such well-regarded 2.5 cc sport diesels of the early 1950's as the FROG 250 and the David-Andersen "twin stack" 2.46 cc model. As such, it appears to be a very suitable powerplant for use in a re-creation of a retro-classic model.


Sugden Special

Next up is a classic from 1950's England - the famous 2.5 cc Sugden Special. Designed by professional dentist and skilled machinist Dave Sugden (who subsequently became a fellow resident of Canada), this engine formed the central subject of a series of construction articles by Dave Sugden which appeared both in the pages of "Aeromodeller" magazine (beginning in December 1954) and later as several chapters in the 1958 "Model Aero Engine Encyclopedia" from the same publisher. The plans for the engine were also published at the same time, with arrangements also being put in place to make sand-cast crankcases available for the use of home constructors. 

Subsequently, my late and much-missed mate Ron Chernich wrote a most informative article on the Sugden Special which may still be accessed on Ron's now-frozen "Model Engine News" (MEN) website. As if this wasn't enough, Ron also published a very comprehensive article based on his own experiences in constructing an example of the engine. That article too remains accessible on MEN. There's plenty of guidance available to prospective constructors!

More recently, I've had a few inquiries from various readers regarding a source of the plans and castings for this very well-designed and strong-running powerplant. Thanks to the kindness of Ken Croft in supplying a hi-res scan of the plan, I'm now able to make it available here. I've also created a pdf file containing the original construction article for the engine.

The construction of this engine requires the builder to somehow obtain an example of the main crankcase casting. Currently I have no information regarding where or even if these castings may be obtained. There is a possibility (and it is no more than that) that my fellow Canadian and former casting supplier Andrew Coholic may be inspired to produce a further batch if there is sufficient interest. 

The illustrated example of the engine was constructed by Andrew from one of his own castings and was very kindly presented to me. I plan to publish a test in due course. Meanwhile, Andrew's video of this example running may be viewed here.



More plans will be added to this page as and when they are received. 


Except where otherwise attributed, all content © Adrian C. Duncan

Coquitlam, British Columbia, Canada

Page established December 2018