Sopwith Swallow (oz2426)

About this Plan

Sopwith Swallow. Scale parasol WWI fighter for KP 01 electric power.

Update 24/02/2021: Added article, thanks to algy2.

Quote: "Sopwith Swallow. Our latest full-size plan - Bill Dennis designed this 25-1/2 in scale beauty especially for KPO1 electric power. Trish Dennis flew it at the Nationals.

HERE IS a simple scale model designed expressly around the new Derek Knight electric motor. Trish wanted to have a go at free-flight scale after some success with duration models, but she didn't fancy diesels, rubber or CO2. The advantage of just switching on and launching are self-evident. With any new power unit, it takes a little time for the optimum size of model to be arrived at; it is noticeable how much larger CO2 models are these days than when the Telcos first appeared.

I designed this model to a similar size as my Bristol 77 published in the May issue of Aeromodeller. At the Nationals it flew well and placed third, but it was a little underpowered; this was partly as a result of excess weight and partly because of the large cowling which blanked off quite a lot of the standard propeller.

I have retrospectively modified the structure to make it lighter - probably to the tune of half-an-ounce. This will do the trick, but it would also be interesting to experiment with propellers, distributing more area out towards the tips.

I have also dispensed with the small amount of non-scale dihedral after seeing Brian Downham's Morane Parasol of similar layout flying perfectly well; some elliptical dihedral usually creeps in anyway.

Get building: Construction is almost entirely conventional, so I will not bore you unnecessarily. The only real design problem was how to arrange wing attachment. The full size wing was a one piece structure, so there is no possibility of using detachable panels, and no serious scale modeller should consider strapping a wing on with elastic bands. The solution was to fix the wing permanently to the removable top decking, which was held in place by internal bands. No locators are used because they often cause damage in a hard 'arrival'.

Engine cowlings for rotary engines are always tricky. Trish was lucky to have one expertly vac-formed for her by a friend, but other options are papier-maiche or conventional balsa construction.

Cover the model with Jap tissue, and steam-shrink and dope carefully. The areas to receive roundels are sprayed white from an airbrush or aerosol can. The roundels are outlined with this colour dope in a mapping compass and filled in with a brush.

To mask off the roundels, stick masking tape onto a window, overlapping by 1/4 in, draw a circle to fit the roundel, peel off, cut out and stick on. The underside should be given a couple of coats of a pale beige car aerosol, and the top sprayed with your idea of PC10; cowling and sheet areas are mid-grey.

The serial number is drawn with a Rotring pen on white decal sheet, using a combination of straight-edge and careful freehand. There are various 'lift here' and 'Swallow' labels, and these are from white Letraset, ref no.1570.

For rigging, use the rubber core from shirring elastic. Take a suitable length and stretch it between the fingers of one hand. Then with a sharp modelling knife, in a shaving motion separate the outer thread winding into half-inch intervals, whereupon it can be easily pulled off.

The model is very stable; it flew 'off the board' in a safe left-hand circuit. The only excitement during trimming was when the model was chased and knocked out of the sky by a passing horse, luckily without damage.

Finally, documentation. A reasonable three-view and several photographs appear in Harleyford's splendid 'Sopwith -A Man and His Aircraft', and there are two superb photos in Chaz Bowyer's 'Sopwith Camel - King of Combat'."

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