Junkers R53 (oz16368)

About this Plan

Junkers R53. Free flight scale model for electric power with KP01 motor, or miniature diesel engine.

Quote: "I found a 3-view of this aircraft in the September 1971 issue of Air International, and had it photocopy enlarged to A4 size, from there taking it to the size required with the aid of proportional dividers. I was visiting family in the US at the time, so this was a tabletop job without the benefit of T-square, let alone a 'proper' drawing board. I built the model using an American ceiling panel as a building board - not as good as Celotex insulation board, but better than solid timber - and cheap - a 4ft x 2ft only costs a couple of dollars.

The fuselage, wing panels, etc, in frame, were carefully stowed in a cardboard box of minimum size and hand carried, with some care, when we flew to visit friends in Arizona. There, in Payson, (Alt. 5,000) and completed, lightly sprayed in silver, a KP01 example, test flown in the town park - not an easy thing to do, as the whole area is heavily forested.

The model was one of a series which I had built to explore the capabilities of the KP01 motor, and was the largest, heaviest, and craggiest of the variety so far tested. Stability was good, the glide ideal - not too floaty - and the climb and height reached during the power run, moderate. In fact a success, since it was probably 'top weight' in all departments, yet flew well and looked good in the air. I had thinned the wing from true scale thickness to reduce drag - with the full thickness wing I would judge that the KP02 would be required, indeed, for a more lively performance, that unit might be considered for this model - if it would fit. Anyway, I left the original with my friend Jim Gray.

As drawn, it can be built in either of two forms for small electric, such as the KP01, or small diesel such as the Mills 0.4cc. If you propose to use the KP01, then you should know that you build to a strict weight limitation. At 125 grams, my models, (I built two), would reach some forty feet height, fly out the charge and land. My target weight had been 112 grams and I didn't make it, perhaps mainly due to the silver auto spray I used to get some resemblance to the bare metal finish of the original aircraft. I had also used tissue and dope. The use of Airspan, without dope, should be distinctly beneficial, whilst the selection of 6 lb /cu ft balsa, rather than the more loosely measured 6 to 8 lb balsa I used, would also pay off.

It may be also that the wood sections for leading and trailing edges could be reduced, whilst controlling the depth of the sliced ribs more accurately than I did, to further ensure lower AUW and gain better climb..."

Junkers 53 from Flying Scale Models, May 2000.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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