RCGF 26cc Beam Mount V2 - RC Groups
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Jul 17, 2016, 12:13 AM
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RCGF 26cc Beam Mount V2


I was looking for a gas engine between 25 to 35cc for a Cermark Pitts ARF. I want to keep the weigh down around 10lbs. I tried the Evolution 33gx but it is 48oz, Dle 30 will work at 38ozs. Then I came across the RCGF 26 BM for $209.00. Claims it weighs 33ozs which would put the Pitts at 10lbs. Bought the engine from Joe at RCGF USA in Arizona. Shipping was fast, engine came packaged well. I'm going to do a review of my experience with this engine and RCGF. Hope it's good, I have heard good things about RCGF.
Last edited by DMHIGHFLYER; Jul 17, 2016 at 12:19 AM.
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Jul 17, 2016, 12:43 AM
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So first thing out of the box is the small exhaust port. The muffler mounting holes center to center is 29mm. I new this before buying it looking at the engine specs. The DLE 20 is 34mm thoughts Pitts mufflers will not mount up. The RCGF 20 is 29mm also so it looks like JTec has one that would work.

Also the exhaust port it self is small for a 26cc. The included muffler mounting holes c to c are 32mm so not a great fit but are large anough to work.

Comes with a off brand spark plug and carb. Looks exactly like a Warbro, also has a RCGF ignition, not a Rcxel.
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Jul 17, 2016, 01:41 AM
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rgcf engines are good engines, I have the 26 and a 20 love them both
Jul 17, 2016, 01:46 AM
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So the 26 BM looks nice and well built out of the box. Wanted to check the weigh, engine, ignition and muffler. Weigh is 33ozs as stated, the engine is 19.8ozs.

I'm using a NGK plug instead of the supplied plug. Also as stated in this months RC Magazine all RCGF engines are test run by Joe at the U.S. Facility. This engine has never seen fuel. So that in mind, I'm going to run it on a test stand before mounting it to the plane.

Another thing is this engine has two piston rings. It also comes with a spinner adapter which works well.
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Jul 17, 2016, 08:36 AM
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I did the same, my engines have started and run consistantly my 26 is 3 years old now, I have to use a starter on the first start after that it hand starts
Jul 17, 2016, 06:47 PM
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Quote:
Originally Posted by DMHIGHFLYER
So the 26 BM looks nice and well built out of the box. Wanted to check the weigh, engine, ignition and muffler. Weigh is 33ozs as stated, the engine is 19.8ozs.
It looks like 25.8ozs to me (1 pound + 9.8ozs) not 19.8ozs.
Not being picky but I have the RCG20 which the RCGF26 is essentially a bored out version of (34mm piston diameter vs. 32mm on the RCG20) and my engine(s) weigh more than 19.8ozs (or 565 grams), more like 730gr (25.7ozs).
The 2 piston rings will keep good compression for longer but full power will be down slightly, you can always remove the bottom ring.
Jul 17, 2016, 07:26 PM
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You are correct, 25.8 ozs Also the crank case is wider, 67mm vs 60 mm on the 20cc.

I have the engine on the stand and it fired right up. It will hand start fairly easy with the prop at the 1:00 position as stated in the manual. I have ran several tanks through it at this point. Running 32:1 with Klotz synthetic oil.

I'm going to run about a gallon through it before I mount the 26bm. Carb seems fine, good throttle response. One thing is the vibration, this thing shakes rattles and rolls not sure what the deal is but, I have a lot of gassers and none of them have a vibration like this. Running a balanced 16x8 Master Air Screw for brake in.
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Jul 17, 2016, 08:43 PM
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What kind of rpms have you seen so far with the 16x8?

The 20's I have (DLE and RCGF) will both turn that prop (and a 17x6) up into the 8500 range.
I was thinking (hoping?) the 26 would be into something like an 18x6?
Jul 17, 2016, 10:09 PM
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Well I have a gallon through it now. So with a 16x8 at 6800 ft asl it turns at 7900rpm. Due remember my altitude, 6800 ft. So I was hoping to get 8500 with a 17x6, but will see.

Also I seem to have some sort of leak, un burned gas, oil coming from the head gasket. Looks like the two back bolts. See pics.
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Jul 18, 2016, 12:06 AM
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Quote:
Originally Posted by DMHIGHFLYER
You are correct, 25.8 ozs Also the crank case is wider, 67mm vs 60 mm on the 20cc.
RCGF had two beam mount RCGF 20 models, the 20 BM (Beam Mount) and 20 SBM (Sport Beam Mount), not sure which one you are referring to.

WRT air and oil leaks: are you sure it is from the crankcase or is it from the exhaust? you should be able to see the difference in the colour of the oil, oil from the exhaust will be darker (after combustion).
Normally tightening the jug bolts will rectify leaks, if it doesn't you may have to remove the jug (cyl. head), check for breaks in the head gasket and if it is due to an uneven surface on the crankcase or jug just sand a bit with a 400 to 800 grit sandpaper.
If it is a major job, contact your supplier for a warrantee repair.

Can you please check the following for me - the distance between the front jug bolts and the distance between the side bolts, you can measure the total distance including the bolts, thanks.
Jul 18, 2016, 01:49 AM
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If it's burned oil, then as above regards out of exhaust.
If unburned, maybe a spit out of carb after choking.
I reckon if the base gasket was leaking, maybe more than a few spots
Agree with ahicks regard props, I run 17x6 (16x8 would be ok) on 20cc engines.
The 26 is almost 33% larger, would be leaning to 18" prop.
(have a 26 bm as yet un-run, so no prop test yet)
Have a few RCGF engines, no probs with any as yet.
Jul 18, 2016, 10:22 AM
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Clipped Wings, the distance between the front bolts is 33mm center to center. The side bolts are 40mm.
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Jul 18, 2016, 03:45 PM
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Ran another 16ozs of fuel through the 26bm today. I tightened the four jug bolts and the muffler after the engine was warm. Once I have the engine on the airplane I will use red rtv gasket sealant and thread lock on the muffler bolts. It does look like the cylinder gasket is leaking though. I'm going to pull it off and see what's up.

Also tuned for max rpms with the 16x8. The best I can get is 7900 rpm. I'm thinking about ordering a 16x8 and a 17 x6 ACP and see if some more rpm is possible.
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Jul 18, 2016, 05:22 PM
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Quote:
Originally Posted by DMHIGHFLYER
Clipped Wings, the distance between the front bolts is 33mm center to center. The side bolts are 40mm.
Excellent, thank you!
Jul 18, 2016, 11:45 PM
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This evening I removed the head on 26bm looking for the leak. There was nothing coming out of the muffler, so I moved onto the cyclinder head. The un burned oil gas mix was coming out of the back of the gasket. Not sure if RTV gasket sealant would work on this application. Going to order another gasket and also a smaller 20cc BM muffler that will fit the 26bm.

Oh yeh, I have a sheet of gasket material and some 400 grit sand paper. May try making my own gasket and also sand any uneven stops. Also I had the engine running very rich, maybe to rich. It could have leaded to the leak also
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