Little Dragon (oz13702)


Little Dragon (oz13702) by Roy Clough 1950 - plan thumbnail

About this Plan

Little Dragon. Model aero engine.

For more details on the Little Dragon engine (and 8 more pages of build notes) see:

First published in MAN, Oct 1950.

Quote: "LITTLE DRAGON. Part one, by Roy L Clough Junior. THE Little Dragon glow engine is 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 in, he need have no qualms about being able to turn out the job. On the other hand, the skilled builder who has a good 'touch' for this sort of thing will discover he has an engine which requires absolutely no apologies on the score of being homemade.

The motor is a basic design, as old-engine hands will recognize by the drawings. It has great amounts of leeway at every step of construction. This means there is plenty of room for the correction of errors, which should appeal to the amateur, and equally of importance, it allows the experienced motor builder to 'soup-up' the design as he sees fit. For example, the weight of the original came out at 2 oz, complete with plug and prop. Skilful shaving-down by experienced machinists can reduce this figure greatly, but this has nothing to do with the operating characteristics. Port areas and valve timing are laid out with an eye to obtaining maximum startability and a good rate of speed with average construction and internal fits, but the experienced worker who is capable of doing very good work will find it possible to increase the porting and degree of valve opening to obtain an extremely hot engine.

The original Little Dragon was turning the plastic prop shown in the photo at 8,000 rpm, 5 mins. after it was assembled. It did this on a break-in mix of 3 parts O&R No.2 and 1 part castor oil. This is the performance the average builder can reasonably expect. For experts, and with one of the hot Francisco Lab fuels 10,000 rpm is a reasonably conservative estimate.

The mounting of any engine uses up time and energy and in too many cases is finicky and bothersome. We have tried to get around this and come up with something that is simple, quick, and practical. The two-stud mount is our answer. Simply press the studs against a piece of plywood to mark it for drilling, set the engine in place and run on a couple of nuts. No muss, no fuss, and no bother..."

Direct submission to Outerzone.

Quote: "Attached are photos [mainpic, 003] of what may be the only diesel in existence, again given to me by David Owen and built by Ron Chernish. My notes make interesting reading. Ed,"

Supplementary file notes

Article (MAN 1950).


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Little Dragon (oz13702) by Roy Clough 1950 - model pic

  • (oz13702)
    Little Dragon
    by Roy Clough
    from Model Airplane News
    1 cc
    Engine Diesel Glow
    clean :)
    complete :)
    got article :)
  • Submitted: 09/03/2022
    Filesize: 172KB
    Format: • PDFbitmap
    Credit*: EdHolly
    Downloads: 734

Little Dragon (oz13702) by Roy Clough 1950 - pic 003.jpg
Little Dragon (oz13702) by Roy Clough 1950 - pic 004.jpg
Little Dragon (oz13702) by Roy Clough 1950 - pic 005.jpg
Little Dragon (oz13702) by Roy Clough 1950 - pic 006.jpg

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  • Plan File Filesize: 172KB Filename: Little_Dragon_oz13702.pdf
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  • Supplement Filesize: 485KB Filename: Little_Dragon_oz13702_notes_ed_holly.pdf
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