rmh

YES- the muffler will make a considerable change in power
Guessing?
No- - a few year back i tested most of the ZDZ engines coming into the USA- ( for the folks who imported em) as well as Evolutions DA's and also made up ignition conversions on ST2300 engines .
Opinions are opinions and everyone has one.
The short story is that on ANY gasoline engine, the exhaust system plays animportant role .
Pipes ALWAYS produce more torque- which results in more rpm - there is NO max torque rating which means anything unless the exhaust system used is factored in.
do emwrong tho and you loose power .
The in cowl small thingys are typically the worst power robbers .
Why?
in a nutshell -theses designs are simply air pumps - and respond just like a table fan.
restrict output and input decreases. No exceptions
The free flowing exhausts empty the chamber quicker (faster flow) which allows the crankcase to pull in more and flow into th e chamber faster - filling it more completely - no exceptions.
A correctly setup pipe , extracts the spent charge faster, earlier , again creating a strong extraction from the crankcase into the chamber - it also stops spillage of fresh gasses out the exhaust -resulting in MORE fresh fuel charge ( density is higher ) and the result is of course - more power .
There are lots of goofy explanations about pipes but the bottom line is - they simply provide for a stronger faster filling of the chamber - period.
Oh yeh -they don't push burnt gasses back into the chamber.
If your model simply does not allow for a full pipe - there are a few (very few ) decent mini exhausts which are not bad - typically tho you need a long header to make any of em work
IF you simply must have the muffler in the cowl- make the muffler as large as possible with a smallish outlet - this is the most effetive setup for least power loss with most noise reduction.
IF you need more power with your ignition engine - switch to alky and 5% nitro and 20-1 synthetic (compatible type) oil.
Now you can use a carb with double the flow and power goes WAAAAY up so does fuel consumption. No exceptions.
I did this with the 2300 Tigres and power, starting etc., was excellent - I did use more oil -of course - 20%
The best of the small engines I tested and used were the 26 Evolutions on a full pipe - best design. on 18x6 props we turned these 8800 on the ground and 10,000 in the air (internal ignition tach)
This new engine should be great for smaller designs whre optimal power per pound is not required -

GallopingGhostler

(deleted as rmh's edited explanation is excellent.)

computermonkey

My Feedback: (90)

A pretty good explanation on tuned pipes, not written by me.

cloudancer03

My Feedback: (22)

Your missing the point.it's gas! A welcomed change nitro fuel caused me to go mostly electric.gas is cheap, readily available, and no mess.you can bet that other companies are going to do the same.amen.I like electrics but now I can fly gas easier than ever. Naturally there will be fine tuning.

GallopingGhostler

I concur. When I procure mine, I'm just leaving it stock. I figure the manufacturer knew what they were doing with the exhaust system and will modify the plane to suit.

vertical grimmace

My Feedback: (1)

I think I will just run mine stock! lol

Mikola

really ? it's an exclusive engine for helis however you have plenty of 20/22cc airplane gas engines outhere
it should be cheaper than GT22 because it's a glow engine version converted to gas but I do expect nothing from tower monopolies

http://www.infinity-hobby.com/main/p...e3f02ecd3485cc

Ernie Misner

>>> It's not like glow fuel at 5:1 that looks like you just dumped oil all over your plane. >>>

Good point. We're talking 20:1 here and that's only 5% ? oil compared to 18-20% oil in glow fuel?

FlatSpin

It may not be like glow fuel residue, but it is a significant amount of a gummy, black coating of goo that is not as easy to wipe off as glow residue. "Goo" is the best way to describe it. I have about 24 flights (~3 ½ hrs) on it so far, and the black residue has decreased a lot, but there is still a fair amount of it all over the airplane after a day of flying. I’m not complaining about it, but this engine in NOT like a typical gasser that only puts out small specks of black stuff. All-in-all, I absolutely love this power plant! After a couple of gallons, I may decide to reduce the oil ratio to 25:1 and see what that does. Yeah, I know, I know...voiding the warranty, replacing parts, etc. but I’ll save that discussion for another day. Besides, Pete did say there were still experimenting with oil ratios.

Dave

Ernie Misner

What kind of oil Dave?

ScottMcM

My Feedback: (66)

I just ordered one of these beauties. I hope to put it on my H9 Pawnee.

FlatSpin

I'm using Pennzoil, air cooled 2-cycle. From what I have read, it is a good quality dino oil. I added some ammonia to my 409 cleaner and that seems to cut thru the goo better.

Dave

David DeWitt

My Feedback: (289)

The engine is running great, just can't keep the muffler tight. The long bolts that runs thru the center of the muffler keeps getting loose and on the last flight today fell off and is lost. I guess I will try to find a one piece muffler as a replacement.

flyinwalenda

My Feedback: (5)

I noticed the main muffler bolt lossens up just like the ones on the glow engines and the sections start to leak like a sieve . I'll have to give it the same treatment I do to the glow mufflers. Would be nice to be able to really seal the sections and the bolt openings as it really pushes out the gunk even when everything is tight.

flyinwalenda

My Feedback: (5)

I ran four tanks through it using a 10X6 prop and now have switched to an 11X6. I ran four tanks through it and leaned out the high end a little more on each tank. On the third tank I was able to hand start it ! Then I ran it up to full throttle for a few seconds to get an rpm reading . On the fourth tank I leaned it out a little more and the transition really improved and it even idled well. Next step will be to install a 13X6 and run a few tanks through it using that prop. So far so good !

www.youtube.com/watch

[youtube]http://www.youtube.com/watch?v=vFn3_m_QXW8[/youtube]

FlatSpin

Yeah, this thing vibrates a little more than a glow and is noticeably louder. I put red RTV around the muffler body (still used the skimpy O-rings with it) and used blue Loctite on all of the screws and muffler bolt. No more leaks. I had to retighten the muffler bolt today after 4 flights but the screws holding it to the engine are still tight. Are you guys having any issues with the amount of black residue it produces?

Dave

Ernie Misner

>>> I'm using Pennzoil, air cooled 2-cycle. From what I have read, it is a good quality dino oil. >>>

Is the Pennzoil just for break in? I think it would run cleaner with a good synthetic. Sure have heard a lot of good things about the Pennziol air cooled oil though.

Kmot

My Feedback: (24)

When I get around to running mine I intend to use the Evolution synthetic. Will be interested to see if the break-in 'goo' is the same as the other oils you guys have been using.

Spridal

My Feedback: (17)

I'm running Redline full synthetic and after 18 tanks the black goo has not gone away.

motomike

My Feedback: (4)

Scott be sure to report how it works. I was thinking the RCGF 15cc would be a good match. I have seen on the Pawnee 40 thread where someone has used the 15cc with good results. Thought the 10 cc would be a bit small.


Mike

ScottMcM

My Feedback: (66)

Will do. I had the choice of the Evolution 10cc or a DLE20.....I plan to try the 10cc first. I have no doubt that the DLE will fly it. I'm hoping that, with the big wing, the 10cc will do the job. Also, the Pawnee is a 40 class airframe, calling for a .40-.52 two stroke glow engine.I'm thinking/hoping the 10cc Evolution should work nicely.

airborneSGT

My Feedback: (15)

Was this engine tested at all with the pitts muffler by Horizon?

FlatSpin

Has the amount of goo diminished very much with synthetic? I will try the Stihl Ultra on my next gallon of gas.

Dave

FlatSpin

There is a huge size, weight, and power difference between the Evolution 10cc and the DLE 20. I fly at ~6800 ft elevation in Colorado and the 10cc is easily the power equiv of an OS 55AX w/MACS muffler, if not a little more. It swings a 12-13" prop. The DLE is a 1.20 equiv and is a lot bigger and heavier than the 10cc. If the Pawnee is a 40 size plane, I am not sure a DLE would fit on it and ground clearance will be an issue w/17" prop. But as they say... there is no substitute for horsepower!

Dave

ScottMcM

My Feedback: (66)

I once put a G20ei on the nose of a 40 size stick. It was fun until the airframe began to fall apart[]....I prefer not to try the DLE on the Pawnee for the same reason. I believe that the Evolution 10cc will do the job. Will let you guys know...