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RCG 15 CC Cylinder rotation

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Old 09-28-2012, 12:32 PM
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Roger Gray
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Default RCG 15 CC Cylinder rotation

I've seen the video of a RCG 15 CC gas engine running and was blown away when I realized the stock muffler was on on the back side of the engine above the carb. The owner had claimed to have made the 90 degree rotation to accomadate for a rear exhaust and logged 30 flights with no problems. Anyone else see this, or has anyone else done this with good results. I love the new generetion of rear carb and rear exhaust engines coming out today-great for my warbird needs!
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Old 09-28-2012, 12:57 PM
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Default RE: RCG 15 CC Cylinder rotation

Post a link to the video please, I would love to see it.

Thanks

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Old 09-28-2012, 04:34 PM
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Default RE: RCG 15 CC Cylinder rotation

X2!
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Old 09-28-2012, 07:32 PM
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Roger Gray
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Default RE: RCG 15 CC Cylinder rotation

Here is the link you requested on YouTube: http://www.youtube.com/watch?v=SgvW_...eature=related


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Old 09-29-2012, 02:28 AM
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Default RE: RCG 15 CC Cylinder rotation

I wish I had seen this a couple of months ago! I asked the tech at BP Hobbies and he (rudely) told me that it wouldn't work, and that rear-exhaust would not be popular anyway.
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Old 09-29-2012, 03:59 AM
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Default RE: RCG 15 CC Cylinder rotation

Neat. Picture of it running pretty much confirms it can be done. I was looking at the owner's comments, think there may be a typo. He's saying he turned the cylinder 90 degrees, then later says he turned it 180 degrees(?). I think he meant to say he turned the piston 180 degrees - so the ring end gap would work out - without snagging a port opening?


Rear exhaust not popular? That's a little out of touch...
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Old 09-29-2012, 05:57 AM
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Default RE: RCG 15 CC Cylinder rotation

Ok he did turn the cylinder and it did run. Bur here are the reasons you should not do it.
By turning the cylinder you block both of the intake ports. This will kill the power, the engine can’t breathe. What’s the point if the engine does not produce any power?
By turning the cylinder the pins that keep the rings from rotating come dangerously close to the edge of the ports.
I have tried to modify all of these engines and when we are successful it comes out as a new version.
The last and best reason not to do it is that it voids the warranty.
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Old 09-29-2012, 06:14 AM
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Default RE: RCG 15 CC Cylinder rotation

I was wondering about how those ports were lining up. The fact it's running means they aren't completely blocked. Curious about how much that did affect the power, ability to turn the same size prop it did originally? Potential for the ports to be cleaned up enough to get it to original power and still hold a good cylinder to crankcase seal reliably?

May have to get one just to mess with. Been looking for an excuse to get one anyway.

Gregg, is there any difference in the ports beam mount vs. stand off mounting?

Anyone asking about or expecting warranty after doing this is just being silly. You're obviously moving well outside the original engine's design criteria with this mod...
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Old 09-29-2012, 07:36 AM
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Default RE: RCG 15 CC Cylinder rotation

Yes there is a difference in the ports between the 15 beam and cross mount. The 15 beam has three ports while the 15 cross only has two. This is one of the reasons that the 15 beam makes more power. The ports in the cylinders match ports cast into the crank case.
The best choice to rotate the cylinder would be the beam mount, but it will require internal machining of the crankcase. If you ask me not worth the effort
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Old 09-30-2012, 05:37 AM
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Default RE: RCG 15 CC Cylinder rotation

The engine's rpm in the video sounded at bit subdued to a normal running beam mount 15cc.

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