Pomilio (oz2357)

About this Plan

Pomilio. Free flight sport power model, for Bambi or similar engine, also shows CO2 power installation.

Free pull-out in June 1986 Aeromodeller. The model dates from 1954 originally, according to the article text.

Quote: "Pomilio. Got a spare small diesel, glow or CO2 motor? Then try this little charmer by Vic Smeed, designed originally for the Allbon Bambi.

This little model was possibly the first free flight design for the Bambi engine, and in fact the original model in the photos is fitted with a prototype Bambi - note the knurled screw compression adjustment, modified for production engines. The reason for the model never having been published was that the late Eddie Keil was considering kitting it, but the initial interest in tiny engines (there were also the Kemp 0.2cc Hawk and the .32cc Kalper) did not develop into a mass market at that time and very few kits were ever produced for the weenies, though of course the Kalper had enough power to fly most of the .5 to .75 cc kits.

Experience has shown that designs (several were published in plan form) for the Bambi are ideal for conversion to modern CO2 power and there are examples of tiny diesels resurfacing after languishing in drawers for twenty years or more. There are also many Cox .010 engines around, plus the .020, which latter should give this model quite hot performance! A suggested nose for CO2 radial mount engines has been added to the drawings.

Construction is simple, even if the fuselage is a little different from usual. Its ancestry goes back to machines like the Banshee (oz1192) and perhaps more directly to Ray Acord's Champion, which used sheet cruciform crutches covered with nylon or silk simply draped on and attached to the crutch edges. producing a very light but remarkably strong and stiff structure. This model takes the method a little further by using thin sheet covering in the 'handling' area and tissue for the remainder, enabling a notional cabin to be incorporated if required. The result is a slightly 'different' looking model which most people seem to find quite pleasing.

One of the crutches has to be in two parts; it doesn't really matter which one, though if it is the vertical one it may lead to economy in cutting and it means that the upper part of the fuselage may be constructed with the horizontal crutch pinned to the sections of former. However, cutting the full profile and attaching the horizontal crutch one side at a time is just as easy. It is, in fact, fairly difficult to get the structure far out of alignment, provided the parts are accurately cut and their positions marked.

Positioning the front bulkhead for radial mount of CO2 motors needs to be fairly accurate to ensure that the thrust line is close to that intended, and this is a matter of accurate cutting of the crutch ends. If CO2 power is intended, incidentally, the grade of balsa selected throughout can be softer and therefore lighter than should be used with glow or diesel engines.

The 1/32 sheet fuselage covering can be applied (grain vertical) though the bottom of the cabin front may be easier and stronger in card. Sand all over and check that everything has been completed ready for covering; this applies especially to the short lengths of 1/8in sq under the tailplane leading edge which are easy to overlook and thus leave a weak spot.

Lightweight Modelspan is adequate for the fuselage but heavyweight can be used. It can be attached dry or wet, but in the former case water shrinking will be required. Four panels will be enough; stick the upper ones to the tail end first and work forward, trying to keep any looseness running down from the after end of the wing platform to a minimum. It's actually surprising how much will shrink out with water and dope, but the pieces of tissue are in any event so small that a second attempt would hardly break the bank. If the edges are stuck down evenly a smooth and pleasant shape will result.

The wing and tail can also be covered with lightweight Modelspan or, for a CO2 version, Jap or similar tissue. Both structures are fairly sturdy and warps should not be a problem.

There is little to say further, except after doping, fuel-proofing etc assemble the model and check that it balances on the line of the centre (top) spar before trying hand-glides. Depending on the amount of power, slight down and/or right thrust may be needed; the safest pattern is wide left power turns and wide right glide turns, but you can experiment. Little models like this tend to bounce!"

Supplementary file notes

Article.

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