RE: DNU Twin modification (CAD)
The Grish 5.5 x 3 tractor and pusher props work well on Cox twin engine projects. Also you might try the Cox 6 x 2 black pusher prop along with the Cox 6 x 3 black tractor ...... the 6 x 2 prop is the one as used on the RTF Cox PT-19 Ukie models. The Cox 6 x 3 tractor prop is actually much closer to 2" in pitch if you put it on a pitch gauge, as is the case on almost ALL of the (underpitched) Cox props. Technically the black 6 x 2 prop used on the Cox PT-19 model is actually a 'left-hand tractor' prop, but most people simply call it a pusher prop ..... same goes for the Grish 'pusher' props, it all has to do with the prop's 'hub design'.