Martinsyde F4 Buzzard (oz899)

About this Plan

Martinsyde F4 Buzzard. Free flight rubber scale model.

Quote: "Build this lovely little 1/20th scale Buzzard designed by one of the top Czechoslovakian scale men, Lubmir Koutny

This type was flown from the end of WWI to the Spanish Civil War. You can find documentation in "Fighters 1914-19" by Munson, Harleyford "Fighters WWI", but the best is in volume one of JM Bruce's "Fighters WWI". To put in the detail for a really competitive model it is essential to refer to at least one of these publications - but be careful not ruin a good model by making it too heavy.

I built it as 1/20 scale in 1972 and it was my best biplane in the WWI competition that took place in Trnava (Slovakia). It is the optimum size for rubber scale and flies even better than the SE5a. A strong climb after ROG to 10m, a steady climbing bruise, even in turbulent conditions, to 40m followed by a good glide. It regularly flies for 60 seconds.

Select only the best balsa for this model, light and strong. If you haven't got any, buy some! Also use a light glue, thinned if necessary. Pin out the plan and cover it with a non-stick, transparent sheet such as thin plastic.

Build the fuselage sides over the plan in the usual way. Use all the tricks you know to reduce the back-end weight. Notice that I tapered the longerons and used smaller uprights and spacers. It is a good idea to build in the two rear peg positions and give some CG adjustment. The front former is made from 1/4 balsa and the top fuselage is covered with rolled 1/32 sheet back to former 6. Rear of former 6 is stringered. The nose block is 3/32 hard balsa and a 1/4 plug, faced fore and aft with 1mm ply to locate the prop shaft. Finish off the nose block with details of the radiator.

Wings. Make the ribs and riblets from very light 1/2 balsa using the sandwich method. Pin the required number of balsa laminations between two 1mm ply ribs and sand carefully to shape. You can try sliced rib construction which should be lighter but the flying results will be the same. The spars should be from very hard balsa. Remember to build in 1 degree washout on the port wing and 2 degrees on the starboard wing..."

Supplementary file notes

Article pages, text and pics, thanks to RogerC.

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