Bucker Jungmann (oz2654)

About this Plan

Bucker Bu 131 Jungmann. Free flight power scale model of the 1930s German basic training aircraft. 36 in span for 1.5 cc power. Scale is 1/8.

Quote: "WHILST ON HOLIDAY in Socarno, Switzerland, in 1965 I was surprised to see that Bucker Jungmanns were still in service as primary trainers with the Swiss Air Force at the local airfield. I spent a morning there and took several photographs of these machines in their attractive yellow and black colour scheme – reminiscent of the splendid Tiger Moths and Blackburn B2s I remember from pre-war days. It was obvious that a similarly attractive and stable model could be produced.

Returning to England I made a fruitless search for available data, but discovered that one was on the British Register at Jenkins Farm in Essex. Descending on this establishment one miserable wet day that December, at the kind invitation of the machines' owner, Ron Fautley, I then spent the entire day taking measurements and photographs from which I later prepared three view drawings which indeed form the basis of this month's Aircraft Described feature.

The model was built early in 1966 and enjoyed considerable competition success in the late sixties. It won the Super Scale Trophy in 1967; being second the previous year.

Being built some eight years ago some of the structure is somewhat dated in design and does not incorporate my latest thinking on this subject. (The BE-12b, for instance, published last March was designed several years later and can be regarded as more in line with my present practice.) Nevertheless, there has been considerable demand for the publication of this design and it is presented as built in 1966 with only a few minor amendments.

All areas and airfoil sections are to exact scale and the structure is as accurate as possible, only notable non-scale feature is the fact that the upper wing has +1° of incidence as opposed to —1° on the full-sized machine as there is no need for a free-flight model to have good inverted performance and with the rather small wing area the extra lift generated is very useful. The engine thrust line is also, by necessity, anything but scale. The only major structural deviation is the large section wing trailing edge. With a relatively small thin wing like this there is really no other sensible practical solution. Thanks to a long nose and sweepback there is, for once, no problem with getting the CG far enough forward. In fact, for once I had to use tail ballast.

This is not a light aeroplane and combined with its large fuselage, in relation to the small wings, requires a lot more power than one normally associ-ates with a 36in. span scale model. It needed all the power of a Mills 1.3 cc engine for take offs on my original. If fitting a modern engine use something of equivalent practical power. Although a relatively fast flyer it is very stable..."

Update 28/06/2016: article pages, text & pics added, thanks to RFJ.

Supplementary file notes

Article pages, text & pics.

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