There’s a 40mph breeze here today, so just to satisfy my idle curiosity I put the MVVS 160 glow into my pattern plane in a direct replacement for the OS 160 which normally lives there.
Both motors are on simple aluminium beams with the bolt spacings arranged so that either motor can slip easily onto four rubber isolation bobbins bolted through the firewall.
The OS has an old RFP61 carb, type 86(big hole, butterfly “barrel”) and an OS pump siliconed into the backplate. The pump operates on the same principle as the Perry VP30.
The MV has the same mods. After problems with the original needle roller conrod, it now has the conventional bronze bushed one, which I think is now the standard offering in the glow version.
Both engiines use OS 4-stroke plugs, and Hatori 907 side-to rear manifolds into the Aeroslave c/f pipe.
The fuel used is 10% nitro,18% Klotz/EDL oil.
My current favourite prop is the Engel carbon 18*11, which to me seems to be a good compromise between the speed of the APC 17*12 and the slowness of the APC 15.5*12 four-blade.
The OS will hold a steady 8300 rpm peak with the above setup; in fact it starts about 200 more then drops back(perhaps Bla-Bla’s right, might benefit from an airscoop)
Idle is an easy 1700rpm, with a smooth fuss-free transition.
The MV idle and transition are very similar, but the peak is lower, at 7900. I didn’t experiment with different pipe lengths, but got the feeling that this was all that the motor would do
My tentative conclusion would be that the MV will cope with pattern requirements ,provided that the model is at the lighter end of those available(and is itself quite a bit lighter than the OS), but go for the OS if you think you need the extra power.
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