Rays Bird (oz14079)

About this Plan

Ray's Bird. Radio control sport model.

Quote: "Ray's Bird, by Dr Mike Hawkins. Gentlemen's aeroplane for .40 - .60 motors and three function R/C.

My friend Ray Smith lives in Tampa, Florida. He is a retired electrical engineer and, like many retired people, only has a limited amount of spare time for his hobby of building and flying model aircraft.

When we are young, we go for the 'roaring forties', but as time goes on, many of us come to appreciate a simple, reliable model preferably with a four-stroke engine, that can be built reasonably quickly and be made ready for flight with the minimum of time and bother. Stable flight and the ability to putter quietly around a beautiful Florida flying site, takes preference over aerobatic ability. It was to this specification that I drew up Ray's Bird.

Ray built it, we flew it and liked it. I don't know how many hours flying it has done so far, but the only untoward incident was when the elevator push rod broke. This was quickly sorted out and when David Boddington, together with John Scrivener (he of the Grumman Duck) visited Tampa in November '97, I was there and we were able to go flying together at TRAC (Tampa Radio Controlled Aircraft Club).

David was able to fly my Bucker Student (Aviation Modeller International June 1996), which now lives in garage and he also had stick time on Ray's Bird. From the grin on his face, I felt he was enjoying the Bird, simple model though it be and afterwards, he asked for the plan. So here it is.

Specification:
Type: 3 channel, cabin type model
Motor: .40 to 60 four stroke engines.
Wingspan: 72 in.
Weight: about 6-1/2 lbs.
Suitability: for beginners or old fogeys, alike.

The engine installs on a dural plate so it may be easily changed. The wing can be one piece or folding. Ray drives a Dodge van, roughly the size of a double-decker London bus, so he chose the one piece wing. The simple brass hinges on the undersurface of the wing have been in use for ten years on my Radio Queen.

I designed the Bird with a fixed tail, but Ray built it with a detachable one, so I have shown this on the plan. He has never unbolted it, as far as I know.

Construction: Experts are not going to need to read this, but the model is very suitable for the non-expert, to whom these notes may be a help. The wing is designed to be built flat on the board, yet have about 2 1/2 degrees of washout. This is very simple to build and difficult to describe but nevertheless, I will try. The aerofoil was not designed on my computer, but works in spite of that.

Start with the lower leading edge sheeting and glue on the leading edge and lower 1/4 in square spar. Decide whether you want the one piece or folding wing. The folding version uses two small brass box hinges screwed to pieces of 1/4 in ply glued to the root rib. The wing folds, lower surface to lower surface. It is fixed by a short aluminium strap,on top, between the two halves. Undo one screw only to fold it up. I have used this system on my Radio Queen which is now over 10 years old.

Then add the ribs, which, because of the slight taper of the wing, will overlap the trailing edge at the outer part of the wing. Trim them off to match the plan and add the notched trailing edge, which should be 1/16 in above the upper wing surface, to be flush when the capping strips are added and about 3/16 in clear of the building board at the outer end.

Complete the upper leading edge sheeting (4 x 1/16 x 36) and add the cap strips. When thoroughly dry and set, take the wing off the board and cut away the undersurface of the outer ribs, using a mini-plane. Hey presto - 2 1/2 degrees of washout. This really helps the flight charactersitics and gives a gentle stall.

Fuselage: As drawn on the plan, the left side of the formers show attached structures, the right side, the outline of the former alone. Attach the undercarriage tubes to the formers with plenty of stout thread and epoxy. Add the extra tube on F4 if there is any likelyhood of using floats later. Make sure your tank will fit in the tank bay. Start with the basic frame..."

Rays Bird from Aviation Modeller International, August 1998.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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