Lightweight Gas Conversion?
 

I have been searching around the forum, but haven't really found what I was looking for. So here goes...

I am looking for a lightweight 35-40cc gas conversion. Absolute power is not as important as power to weight. I would like it to swing a 20x10 or 20x12 prop around 6800-7000 rpm on a full tuned pipe. Rear exhaust would be preferable but not essential. Is there a suitable candidate to look at or is this simply an impossible wish list? I am willing to change carbs if necessary and it will get an EI conversion. Some light port work and general clean up is fine as well. Low cost is not as important as getting something that is not really available at the moment.

The Brillelli 46GT is close to what i want, but is a bit heavy for my goals. If there was something that weighed about 5-6oz less than the 46GT and made around 85-90% of the power that would be perfect...


Thanks,
Mark

RE: Lightweight Gas Conversion?
 

Try a Brillelli 36 its the right size and is rear exhaust

RE: Lightweight Gas Conversion?
 

What about a G38 on ignition?

RE: Lightweight Gas Conversion?
 

Brillelli 36 - I had looked at it but concluded that it would be a bit light on power. I was just running some prop/power calcs and if I can get 6800rpm from a 20x10 I would get around 20lbs static thrust, which should be lots for me. I'm not sure that it will do that, however. Last time I talked to Scott he had no pipe data on the 36. Maybe that has changed since, I will have to see if he has more info now.

G-38 - I was under the impression that they were a bit heavy and underpowered. Do they respond well to a pipe?


Thanks,
Mark

RE: Lightweight Gas Conversion?
 

If you shop around you can get a good running G-62 for less than $300.00.
You won't need a pipe and they will last for ever.

I have one in a 108" Mr. Mulligan and it is impressive.

You can do a little research and come up with the weights.
I'll bet it's not that much more. And maybe even less if you go to full EI.

By the way the G-62 is a chainsaw engine and will turn 10,000rpm.

The only replacment fo cubic inches is cubic feet.

RE: Lightweight Gas Conversion?
 

Mine spins a 18x10 MA Schimatar at 8700. Never tried it on a pipe. It's sitting in my DR1 right now. I had it for sale a while back. It has an aftermarket cup mount, throttle linkage, and muffler. If I had an engine stand, I would pull it off, fab up a header real quick and throw a pipe on it. I have some laying around. I bet you could get that 6800 on the 20x10. My OS 1.60FX used to spin a Zinger 20x6 at about 7700. The 38 and 1.60 spin the 18x10 about the same, so I'm guessing it would be close. I don't think I have any 20" props laying around. I look later and if I do, I'll slap it on and see what it does.

RE: Lightweight Gas Conversion?
 

The G-62 weighs 4lb even, with ignition and no muffler. I have one sitting on the shelf right now. It would definitely kick ***** for this airframe, but it is way too heavy.

I want this engine for a 2M pattern plane and the weight is an issue for that application. I am not competing with it, but I want to stay close to the 5kg limit to retain the flying characteristics. If I can get a 20x10 to around 6800-7000rpm and keep the weight down around 5kg, it would be perfect for me. I will get in touch with Scott at Brillelli and see if he has any newer test data on the 36GT with a pipe.

Thanks,
Mark

RE: Lightweight Gas Conversion?
 

If you really want some good advice contact Ralph at Rcignitions.com
He has a small Q&A forum that's worth reading.

He's been doing this a long time.

http://www.rcignitions.com//index.ph...ntact&Itemid=3

928.635.2455

Don't call him for a couple of weeks though. It will give him time to finnish up my project:D

RE: Lightweight Gas Conversion?
 

Ralph is a great resource, my G-62 is a conversion by him and his work is superb. I will have to check in with him regarding an EI G-38 for this application. It may be a great choice after he is done working it over and removing material. Good thing I am in no hurry to build the plane, it will be awhile before I have the engine sorted out...

Mark

RE: Lightweight Gas Conversion?
 

Here's a pic of a G38 that Ralph did. I found in an ad here. I'm going to test the 38 on a pipe here soon. Just give me a week or so.