XFS-1 - Rubber model with contra-rotating prop. This X.F.S.1 plan appeared in the article titled: "Coaxial Aircrews"
Quote: - "CO-AXIAL AIRSCREWS by C.F. HEDGES & R. V. BENTLEY - One of the neatest co-axial propeller designs that we have yet seen which will no doubt be welcomed by the serious aeromodeller. The actual gearing is a little intricate but should present no especial difficulties to the model engineer. The photographs show the excellent form of construction used and the pleasing lines of the finished machine.
Before commencing the instructions I wouls advise anyone about to build this model to obtain the best quality material in order to obviate any weak spots. As will be noticed, weight has been cut down where possible in order to allow for places which need extra strength. On the original model the props and mechanism worked out lighter than was expected and this necessitated the addition of a slight weight on the nose in order to balance the model, but including this extra weight the finished model, with 1 oz. of rubber, weighs only 5-1/2oz, which you must admit is not bad for a job with two props and gears. To get to the building, we will commence with the fuselage.
If you have built a circular fuselage before, no difficulty should be found. The first thing is to cut out the formers as shown on the plan, using two laminations of 1/32in sheet, marking for stringer positions and longeron slots using the master diagram. Former No. 4 (three-ply) is for strength in order that the fuselage will not collapse when the wing fixture is cut away. Former No. 11 (three-ply) is for the rubber fixture and rudder control attachment. This fitting should be made as shown on the plan and fitted before the fuselage is assembled..."
Quote: - "Hi Mary and Steve, I'm sending an incomplete [complete now] article on coaxial propellers I have, written by C. F. Hedges and R.V. Bentley, which appeared in the May 1942 issue of Aeromodeller. The article gives a blueprint to build a contra-rotating propeller and a plan for one of the the typical beautiful streamlined and complex British rubber models of the era to use it. I hope Jeff finds it useful, even if it's not complete. Best regards Alcalaino"
Note this is not a full size plan, this is a cleaned up scan of the drawings as published in the magazine in 1942. Fuselage and flying surfaces are drawn at 1/3 scale, but the formers and ribs are shown at full size.
Direct submission to Outerzone.
Update 13/01/2018: Doh. Have added full article file now, including the missing first page.
Article pages, thanks to Sundancer, rchopper56.
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