Re: Has anyone ever ran a 2s through a 4s muffler?
hi Paul (and Dave)
I've fashioned some pretty minimal muffler arrangements on 2 stroke engines all in the name of preserving a scale, cowled-in appearance - and seen a lot of other similar efforts and they have been successful in terms of flight performance and no damage to the engine.
If you read through old Clarence Lee reviews of two stroke engines in RCM he would typically make comments that 'x' muffler robbed 500 or 1000 rpm compared to another muffler and comment on relative noise but I don't think I ever read a comment to the effect of a 'poor' muffler threatening damage to the engine.
More important than the size of expansion chamber of the muffler is good air cooling of the engine - if the engine is mounting on its size, I would just leave open the cowl inlet directly in front of the engine cylinder and open up a good size exit hole - 2,3 times the inlet cowl hole - at the bottom of the cowl, where it doesn't detract from appearance.
I looked at the instructions for your plane..... .074 to .15 engine on a high drag model, so with a .15 size two stroke I would think you will have plenty of power to spare despite a less than efficient muffler arrangement in the name of appearance.
I'm not familiar with the MVVS .15 engine you have but I understand that some of their engines were high rev'ing, race engines, so in the interests of further protection from overheating I would not try to run it over lean and would use a fuel with some castor oil lubricant.
just my thoughts, others may differ
how about some pictures?
good luck,
Michael
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