Poppet (oz16763)

About this Plan

Poppet. Radio control sports aerobatic biplane model. Wingspan 43 in, for .30 to .40 engines.

Quote: "Modellers who make scale replicas of a chosen subject are a very patient bunch. They can spend hundreds, even thousands of hours on researching and building with meticulous attention to detail, and thoroughly rewarding it can be too. Then they take their creation out into the big, wide world where some 'anorak' will inevitably have to pass a comment to the effect that, of course, the full-size one

didn't have that, or something is in the wrong place, or something else is missing altogether. Usually based on the fact that they once saw one at 400 yards 30 years ago or, with even greater authority, their uncle once knew someone who mixed the paint for the tail wheel springs some time before the war.

I don't know quite where these people come from but they do seem to materialise around any model that looks remotely scale. Once a sense of mischief kicks in, it can be fairly easy to have some fun with them - or you can avoid these interesting conversations altogether and build a sports model that looks like an aeroplane, but without the complications of any full-size heritage to worry about.

With this in mind I readily undertook the task of building a very pretty biplane which was originally designed by Maurice Ashby (the Editor's daddy) in about the year 10 BC (before cyano). Obviously inspired by a Pitts Special it also has shades of Little Toot in it as well. The original model was much admired by the (then) very young Graham Ashby when he was still a little boy, and the memory of it has endured and left a lasting impression, so when the plan for it re-emerged recently, he just had to do something about it. The original has been re-drawn in a few places as a concession to modern construction methods, but the outline remains the same.

The model is at the small end of being medium sized and although the construction is relatively straightforward, there is quite a bit of it. The aircraft is all built-up, so don't expect to start building on a Monday and be flying by Wednesday evening. But if you are looking for a project to soak up a few hours of your time...

The best way to start building the fuselage is by cutting out all the plywood formers. Then drill all the holes for the engine mounting, fuel lines and throttle cable. Once you have all these components you can start the build in earnest. The construction is slightly unconventional m that the sides are not vertical but angled out towards the top. The sides themselves having a thin plywood doubler.

The top wing is mounted on a 1/8 ply cabane structure which is permanently glued into the fuselage. The wing itself is held in place with rubber bands. This is an area which can be modified to suit individual tastes. I'm sure many people would prefer a bolt on arrangement, but for the sake of the article I wanted to follow the original plan.

Once you have the basic construction with the formers and wing supports in place the tail and fin are added and when dry you can start planking the top half. It pays to make this from a fairly soft grade to aid shaping to the desired Et. This is quite time consuming but very rewarding when finished.

The undercarriage is secured to a plywood floor using bolts and captive nuts - and a spot of thread lock. The engine can be mounted upright, but the model cries out to have it inverted. Side mounting may prove difficult as, if the thrust line shown on the plan is to be maintained, a standard silencer may not clear the bottom of the fuselage. The engine on mine is inverted and the engine itself is the utterly superb MVVS 40. More on this later. Once the engine is in place, build the cowling around it..."

Poppet from RCM&E May 1998.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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