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RCGF 15cc petrol

Started by Brian Cooper, October 15, 2010, 16:50:56 pm

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Brian Cooper

RCGF 15cc petrol engine.

After 4 hours of running time.
Running on fully synthetic oil @ 50:1 mix.. .  and at 3,500 ft up in the Spanish mountains.  :)

The engine starts easily and runs well, but by heavens, it´s a bit noisey... especially on the smaller props.

APC  13x7 . . . . . .  . . . . 11,300 rpm
G-Sonic 14x7 . . . . . . . . .10,100 rpm
APC 14x6 . . . . . . . . . . .  9,600 rpm
Wood 15x6 . . . . . .  . . .  9,300 rpm
G-Sonic 15x8 . . . . . . . .  8,300 rpm  :af
Master Airscrew 14x8 . . 7,900 rpm
APC 14x10 (pattern) . . . 7,800 rpm
Just Engines 16x8 wood . 6,700 rpm.

The G-Sonic 15x8 helps to keep it quiet and it also pulls better then the higher revving props.

B.C.



gavin mack

Which silencer are you using?
Gravity never loses, The best you can hope for is a draw
It takes 2 years to learn how to talk, and a life time to control your mouth.

stukno


Why are you testing it up a mountain in Spain?

stu k

Brian Cooper

Quote from: gavin mack on October 15, 2010, 18:43:22 pm
Which silencer are you using?


The silencer (amplifier..??) is the standard one which came with the engine.

B.C.

TonyKing

Quote from: stukno on October 15, 2010, 21:04:11 pm
Why are you testing it up a mountain in Spain?

stu k

Because with an engine as noisy as this one you have to run it as far from civilisation as possible!

(The silencer outlet bore is approximately twice the size of the inlet).   :o
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Brian Cooper

Quote from: stukno on October 15, 2010, 21:04:11 pm
Why are you testing it up a mountain in Spain?

stu k


Because it was bought for a buddy who lives in Spain.  Fortunately, the area where he lives is very remote and he has no issues with the noise upsetting anyone.  :xx

B.C.

brand1068

Geeze they're not That noisey :)

I have one in the wife's cub with a 14x8 great little motor.

Hand starts like a dream every time - unlike my crrc.

Chris

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dogshome

8400 13*8 master after 20 mins.
Not schneurle  ported and v noisy, but very easy handling.
肉(ròu)包(bāo)子(zi)打(dǎ)狗(gǒu) (meat+bun(2nd and 3rd)+hit+dog)
Literally: To hit a dog with a meat-bun

dogshome

8,800 on Graupner Sonic 13*8 and pitts muffler with restrictors in outlets.

Not noisy  :)

Revs-up like a fun-fly glow engine also  :co
肉(ròu)包(bāo)子(zi)打(dǎ)狗(gǒu) (meat+bun(2nd and 3rd)+hit+dog)
Literally: To hit a dog with a meat-bun

paulinfrance

I 'tweaked" mine a little bit, I get 8,500 rpm on an APC 14 X 8 Prop, I have tried from 5% down to 3% petrol mixes with no difference, I also changed the timing from 32° down to 28° to stop it vibrating so much.
Mode 2 THE only way to fly

dogshome

No vibes here! Little thing keeps on trucking. Not the most powerful, but very reliable absolutely no trouble. I've never had to change plug or carb gaskets!...

In fact it has never quit, always goes on the starter and is a pleasure :-)
肉(ròu)包(bāo)子(zi)打(dǎ)狗(gǒu) (meat+bun(2nd and 3rd)+hit+dog)
Literally: To hit a dog with a meat-bun

paulinfrance

I ran up a friends RGCB 20cc Monday and it doesn't vibrate like mine does,,,
Mode 2 THE only way to fly

Engine Doctor

I made an exhaust baffle that fits in the pipe on my RCGF 15. I looked on line and found the pics of items similar to the ones supplied by just engines and turned some up. It really reduced the noise and doesn't appear to have reduced power that much . Maybe 100 or 200 rpm down on max . Run on ground for 20 min and doesn't appear to over heat . I also upped the prop from 15 x 6 to a 15 x 10 wooden will test fly this summer . I also fitted a baffle in my DLE 30 . It reduced the noise really well with no adverse effects . Provided the silencer doesn't crack and  fall apart like the DLA silencers supplied with the 50 it should be ok. Half the trouble is the thin gauge ali used for the standard supplied muffler (amplifier )The otherhalf is the lack of any baffles !
Take off's are optional ,landings are not !

paulinfrance

Got any pictures of your baffles ?.
Mode 2 THE only way to fly