Cadet (oz3503)

About this Plan

CO2 Cadet. Free flight model. Scaled down vintage design for CO2 power.

Quote: "THE WRITE-UP FOR the original 1938 petrol-engine version of the Ben Shereshaw designed Cadet (oz1131) describes it as an intermediate-step model, a progression towards larger and more intricate 'gas jobs'. This craft was 87-1/2 in span and was powered by a 1/5 hp Brown Junior engine which, it is said, gave very creditable and stable flights averaging around ninety seconds.

This CO2 version of the Cadet is somewhat smaller, but should give equally as good a performance. The outline and general appearance have been maintained but obviously some of the structural design has had to be changed. The original was quite a chunky model; the fuselage longerons alone were from 3/8 in square.

This little version should not pose any problems for a modeller with some building experience, and it is probably a good choice for anyone wishing to get started in CO2 or the vintage scene.

Just for interest and to let you fellow modellers know (if you already didn't) how high-tech has crept into our hobby in more ways than one, I can reveal that the design, detailing and drawing of this model was carried out using a CAD unit; that is, a Computer Aided Draughting unit and plotter. The CO2 Cadet is untouched by human hand, so to speak.

Let's start with the fuselage! Select the longerons from 3/32 sq medium hard balsa, Try to match these for grain and weight. Before pinning anything down over your plan, cover it with a thin layer of polythene sheet, which will stop any glue from getting onto it. I used PVA adhesive for all the wood joints and araldite for the wood-to-metal bonding. There are no difficult curves to this fuselage, so no steaming or soaking of the longerons is necessary.

Start by pinning down the longerons and the straight centrepiece over the plan. Pin either side of the strips rather than through them. Now add all the 3/32 sq vertical spacers. These can be from a softer grade of balsa than the longerons, and should be cut so that they go into place with the slightest pressure. If they have to be forced in they will distort the longerons. The diagonal spacers have been left in to maintain character, but they are not really necessary for strength. They can be from 3/32 x 1/16 or even 1/16 sq.

A novel feature is the undercarriage springing which consists of the rear undercarriage leg sliding between two hardwood guides in the fuselage, with rubber strip to take the landing shocks. Make sure that the two parallel diagonal spacers are from hard balsa.

The second side is built directly on top of the first to ensure a matching pair. When dry, remove the frames from your board and carefully split them apart. Choose which faces are to be the outsides of the fuselage and lightly sand them smooth with the aid of a sanding block or fine sandpaper wrapped around a piece of wood or balsa.

I have tried to keep as close to the original design as possible which means that as there are no main formers in the fuselage, there are none in this miniature. Building up the fuselage is done using 3/32 sq cross pieces only..."

Supplementary file notes

Planfile includes article.

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