Focke-Wulf 190 (oz2648)

About this Plan

Focke-Wulf 190. 52in span semi-scale C/L stunt model. For .35 - .40 power.

Quote: "Another attractive fully acrobatic design from Claus Maikis. A semi-scale Focke Wulf 190.

WHEN I SAW Dave Day's Iroquois way back in June 1963 AeroModeller, I knew that I just had to build a radial cowl model one day. That day came three years ago, when my Domino design was just finished - and there was still a long winter in front.

There are some designers who claim that their stunt aircraft are built to exact scale dimensions, or at least as near as possible. What is the purpose of this? If the model lacks in performance - and it almost certainly will - the stunt judge will not give him any bonus points for his geometry. After all, we are flying aerobatics. My Focke Wulf 190 is not a scale model; I just intended to retain the overall shape of the full size. As with a caricature, concentration on the most specific detail - and sometimes even over-emphasis - will help expression more than the exact replica. The onlooker simply ought to get the impression of a Focke Wulf 190.

I did not want to deviate from typical 'stunt dimensions' other than to use a relatively short nose and even that was compensated for by renouncing the usual shaft extension. The nose seems to be rather 'chubby', but after checking, it has very little more frontal area than, for example, the Nobler (oz6212). Also there is hardly any more wood in the construction, so the increase in drag and weight will be negligible. The wing has a 15 per cent airfoil at the root and nearly 20 per cent thickness at the tip, both at 28 per cent chord. Thus, the airplane can be flown quite slowly, if you prefer.

Engine is my old reliable OS Max H40P. I made a new venturi with a 6.5mm bore, while the spraybar is from a Taifun Bison engine. This spraybar has threads on both ends and thus can be accurately fixed with the admission hole in the middle of the venturi. This hole is very small which certainly helps carburetion, while the thread is very fine, making for a non-critical needle. The knob of the needle is replaced by an angled piece of wire, which is much easier to operate and to check. My last venturis were made of nylon, because it is easier to obtain and faster to work on. I mention all this, because many big engines today are only available with an throttle, and I do not like to run my engines with a throttle fixed in the open position.

The 10 x 6 three bladed Tornado propeller looks best with this aircraft - alas I was not satisfied with the performance! A normal 10 x 6 two blader seems better, while I had best results with an 11 x 5 in propeller. If your engine can cope with the bigger prop, it should be preferred, but it has to be selected and reworked carefully (pitch and airfoil) in order not to overload the engine. Muffler is the original OS Max type. Though it absorbs quite a lot of power, it produces a somewhat metallic, biting sound..."

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