15 and 21 aero engines

[rpringle1028]

Thanks to MECOA for indicating that the bolts on the 21 engine are 4-40. I finally figured out that the bolts on the 15 are 3-48 (not a usually available size in Canadian hobby shops and hardware stores it seems).

Is there supposed to be a head shim/gasket and a backplate gasket on the 15 (Model 8301). The example I have does not have these, possibly indicating that the surfaces were machined and do not require these.

Rob

[MECOA]

Which 15 are we talking about? The 15R or the Torpedo 15?

Both should have cover gaskets, head shims maybe, maybe not.

[rpringle1028]

This is the Series 72, Model 8301.

I asked about the backplate gasket since this is a rear intake engine and the gasket would change the clearances between the crankpin/crankshaft and the rotor. I have made a backplate gasket from 1/64" auto gasket paper and a head /shim from aluminium from a pop can.

Thanks.