Foo 2 (oz1998)

About this Plan

Foo 2. Free flight rubber power contest. There is some disagreement about the span of this model, as the plan is ambiguous, shows no centreline on the wing. Either 23" or 30" span, depending how you read it.

Update 29/06/2020: Replaced this plan with a clearer copy (patterned background removed) thanks to TonyP.

Update 3/8/2026: Added build notes, thanks to Andrew Longhurst.

Quote: "Hi Steve, Some stuff you may want to add to the Foo 2, from this extract from my column in SAM 35 Speaks. Edit by all means. Regards, Andrew.

A strange conundrum surrounds this little plane which first appeared in the June 1943 Aeromodeller. Is it 23ins span or 30ins? There is no centreline shown so shall we assume that the whole of one wing is shown, or shall we assume that as two ribs are shown closer together than the others this indicates the centre line is between the two?

The greater weight of evidence points to it being 30ins. If the span were only 23ins the tailplane would be almost 50% of the wing area and the fin 20%. This tail volume is a bit unusual but could be accommodated by a rearward CG. Then there is the prop specified at 11ins. In 1943 a typical 24ins model would have a 9ins prop, An 11incher is more typical of a 30ins span job. Everything points to the larger wing being correct except those close together ribs in the flat panel which are difficult to explain. This particularly as the 1ins spacing bears no relation to the fuselage width which is 2ins. Well, maybe it does as this might be a drafting error and the narrow gap should be on the right-hand end of the half wing instead of in the middle. That then makes everything fall into place because the middle double bay becomes 2 ins and that fits the fuselage. Was the draftsman all at sea or was he working from a messy pencil sketch supplied by the designer who might well be a teenager. Maybe he had been on air raid warden duty all night and was half asleep.

Whilst building one sees other things, like there is no flat bit on the top of the fuselage on which to mount the wing and no indication of where it should be. The fuselage is on the short side, so the large tail is welcome but with twin fins it’s going to be relatively heavy. A requirement for nose-weight raises its ugly head. I chose an Alan Wiggs carved spade-blade 12in to whittle down to 11inches incorporating a nice elliptical shaped blade. In the end it worked out the same weight as an 11ins plastic prop but will probably work slightly better. I glued the Tomy in as near the front as possible anyway.

In the end, with the wing LE placed 4ins from the front the CG came out at 60% of the average chord, just right for the 30ins wing. The smaller wing would ideally need a CG further back but maybe a bit more incidence would do. At every step it becomes more obvious that this was never intended to be 23ins span but we shall see.

First outing was a false start as there was a problem with the prop shaft. Some test glides with the large wing were possible and showed up some under elevation corrected back home later with two 1/8 square runners along the top longerons where the wing LE sits.

Back on the meadow in cool overcast conditions and a 6mph breeze, a 25g x10st of 1/8 motor powered firstly the larger wing version. On 300 turns it turned a little tight to the right as I had built in too much right thrust. A .5mm shim in the right side of the noseblock sorted this out and away it went. Building up the turns to 800 it ended up flying very nicely climbing high and gliding pretty well.

So now to fit the smaller wing. We decided it would end up significantly under elevated. To our surprise on 300 turns it powered away exactly as it did with the larger wing and the glide was only just noticeably steeper. As the power flight was so good we decided to go with tail weight rather than more incidence. With a blob of Bluetac on the back it performed exactly as it did with the large wing. Moving the CG back turned out to be correct for what was now an oversize stab. It turned out that which wing you use doesn’t matter at all! The smaller wing will probably climb higher but not glide so well.

This is a really nice easy to trim but sadly ignored and forgotten design. With its tapered tips and twin fins it looks charmingly period and clearly it was desperate to fly its dear little heart out. I find it sad that its possible it will never be built again by anyone. A ray of hope is that a full-size plan is on Outerzone and it’s free to download. Tempted?"

Supplementary file notes

Build notes.

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