Quarter Scale Bentley BR2 Rotary Aero Engine

Mick Knights completes his aero engine.

- Mick Knights

Now for the finishing touch, the propeller. There is a drawing for what's described as a 'cooling club' with the Hodgson set of drawings. I'm sure that its effective in cooling the engine and would be relatively easy to produce from a suitable piece of timber but, to be honest, visually I didn’t find it very appealing.

The general thinking on the subject, from those in the know, is that a 28 inch diameter prop with a pitch of 28 x 10 is the ideal configuration for this particular engine. Propellers of the same configuration and with a sympathetic profile to the WW1 originals are readily available off the peg from online outlets such as 'Prop Guy' for around the £70 mark. The only problem with a ready-made version is the diameter and thickness of the central hub, which are quite a bit smaller than the ¼ scale mounting hub on my BR2 and so would look totally out of place and would spoil the overall appearance.

There is a detailed drawing of the propeller for the Blackmore version. However, my woodworking skills do leave a lot to be desired and I wouldn't really know where to start in order to fashion such an intricate and complicated form - let alone have both blades in complete balance. I don't think that I'd want to be around any propeller that I'd fashioned, when the engine was running!

On the subject of balancing both blades, the Blackmore build notes recommend adding extra coats of varnish in order to make the lighter blade heavier and thus bring both into balance - now that would definitely take me way outside my comfort zone.