Enya .09 II Questions

sosam117 wrote:
In that short section are three pipes -- the two on the outer diameter send the pressure towards the middle tube where there are holes in that center tube to send the gasses out the final hole in the cone of the muffler.

See the photo of the "silent" M154 muffler that I have cleaned up and while cleaning it I was able to unscrew the end cone off.

No, that is not the SM154 muffler. The one shown is for a larger engine. The SM154 (i.e. .15 size) has no tubes on the inside, only a flat baffle with a hole, similar to the OS .10FP and .15FP engines.

Greenman38633 wrote:Ok purchased.    I’ll let you know when I get it and on.  Thanks for the heads up

Ok got it in the mail today and installed it. It sure is bigger than the other one. Should make a Good deal of difference. Thanks

Here it is

Greenman38633 wrote:

It looks good, @Greenman38633 .

Just my personal opinion, but in life there are no perfect answers, just suitable compromises to make things work. If it is a little down on back pressure for idle tells me that you set idle a touch higher.

The other muffler, original for the 1965 .09-III TV, could be possibly stuffy at highest RPM on smaller props. Depending on your flying style, may still be OK, say on a 7x6 or 8x4 prop. And, as you suggested, opening up the priming port baffle or removing the baffle leaving priming holes exposed could reduce back pressure if need be.

I have a 1965 OS Max .10R/C with a muffler for the larger .20 engine. The original muffler is as rare as hen's teeth. It fits perfectly, but has a larger chamber than the original, about akin to your new Enya muffler on the .09. Haven't benched it yet, but have confidence that it will still work with the larger chambered muffler. Perhaps an up side is that it will not rob top end RPM's as much as the original muffler.


Gift from a friend, Dane in Los Vegas, NV.

This engine similar to the III came with a ganged exhaust baffle for idle, which light weight at 3.1 oz. is ideal for that anemic .049 aircraft, converts them to decent sport planes.



The neat thing with either the unmuffled Enya with ganged exhaust baffle or OS with ganged exhaust baffle is that being one sided exhaust, the noise from them is the same as an unmuffled .049, but at lower throttle (half and below) sound like it is muffled.


If noise is not a problem at your flying field, or they permit unmuffled half-A's, these unmuffled baffle plate engines are the least restricted at top RPM.

I haven't compared the running performance of the .15 muffler with the stock one, I've just found it unnecessarily large, but hopefully it will run just fine. If there is an issue with low fuel draw, one can also vary it a little bit by adjusting the spraybar position. From the pictures it seems to be pretty far in already though.

The last time a used the .09 engine regularly I used the stock .09 muffler and 7x4-7x5 props (see below). I've tried MAS and APC props, but the Rev-up wooden props were my favourite.

The MAS 8x3 didn't work well for RC flying, in my experience, it required full throttle all the time in order to have any forward speed.

In my notes I have it doing about 14500rpm on the APC 7x4 prop and 10% nitro (20-25% all castor), same numbers for the plain bearing and BB versions. So not very powerful, but lightweight and reliable.

Kris, I don't have a later IV to compare. I think Enya must have tweaked the porting in the cylinder a bit and may be the carburetor as well. And, regarding an 8x3 prop, found it interesting that not all props in same sales dimensions perform the same. My Enya literature that came with my .35-V TV specs the earlier IV and single ball bearing one. With the IV, Enya reduced the 8x4 prop to a 8x3 and 7x6 to 7x5 (depending on mode of flying).

It would be interesting one of these days, if someone who was tearing down both would make side-by-side comparisons to notate differences between the two, besides what side exhausted from.

I don't have an electric starter, so I hand flip. Found in hand flipping, the III TV likes lower inertia wood props, but had a harder time hand starting and getting a good needle setting with the heavier plastic props. It became easier to hand start in the field with a 7x6 wood. Once started, needling became normal. With the plastic props, it was harder to find the right setting.