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Century Helicopter . MTA Hobbies . Model Rectifier Corp

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Gasser Model RC Helicopters > Plug reading
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

I put tanks two trough five through my Predator today. Flew great. I started off with both needles at about 1.5 out, after tank three was done I turned the LS in about a screw driver width. The heli seems to be running pretty smooth. I can't beleive how little fuel I've used so far. It was easily over an hour in the air but I've used about 1/3 gallon. My last flight was about 20 minutes with 1/5 tank still left. The muffler is getting quite a bit of black oil residue splatter on the back and I can see light oil smoke in the exhaust. My temp measurements were max 170F right around the exaust port.

Headspeed is low, I'm guessing 1300-1350. I did some light aerobatics, loops, rolls a few auto's never really pushed the machine or engine. My throttle curve is quite flat right now, I don't get above 30% until near full throttle. Never felt like it was working hard except a few climbs, even then not a hard grunt just chugging up hill a bit. There is not a lot of power/punch at full throttle, still too rich for that.

Anyhow I wanted to get everyone's opinion on my plug now. The black stuff around the edge flaked right off. The side electrode looks to have a bit of a black shine to it. Do I need to lean this out a bit before I stick the piston ring?

BTW - auto's are cool, better than I though it would be with the light RT710SG-3D blades. The gear noise is pronounced, makes it sound like a turbine coming in!



...yep...
04-20-2008 05:31 AM
 
 
FCM
Elite Veteran
Location: Back in Blighty!

What oil and mix are you using? The centre electrode looks hot and dry and the outer looks clogged up with oil residue. What engine RPM is 1300 rotor rpm?

My guess is that you are overloading the engine a bit as the carbi adjustments sound good.

Paul.
04-20-2008 07:30 AM
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

4oz. of Lawnboy ashless to ~128oz of 87 octane pump gas.

Gear ratio is 6.28 so engine would be running somwhere between 8000 and 8500 RPM.

I really don't think the engine is getting hot at all but perhaps I do need to speed things up a bit since I'm out of the power band ??

Really lovin' the gasser

...yep...
04-20-2008 06:41 PM
 
 
xcellgasman101
Elite Veteran
Location: WOODWARD, OKLA....

What engine?? 231 or 260, the 231 will like a higher rpm, the 260 likes around 10500rpm,,,

Yes way to low of a head speed,, you should be 1650, to 1700 for around 10,500 rpm on the engine,, this will bring your heli to life, for aerobatics,, Now if you wanted to, you could go to around 1550 for just hovering and easy ff, but I would bring the head speed up to around 1650 if I were you,, IMHO,, XGM/VGM

John Crotts
www.soonerhelicamproductions.com
04-20-2008 07:08 PM
HOMEPAGE  
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

Hanson G260PUH - the Hanson that Century sells

...yep...
04-20-2008 10:04 PM
 
 
AceBird
Elite Veteran
Location: Utica, NY USA

Quote 
Headspeed is low, I'm guessing 1300-1350.

Why??

Get it up at least 1500-1600 or stop guessing...

Ace
What could be more fun?
04-21-2008 12:49 AM
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

I do need to get someone out with me to tach the HS. I suppose I was leaving the HS low with the intention of taking it easy on the heli. Probably would be better to step it up and get the fan spinning.

...yep...
04-21-2008 12:59 AM
 
 
FCM
Elite Veteran
Location: Back in Blighty!

Yes, get the speed up and don't guess - get it tached. You should find the engine and heli will be fine after this. Leave the needles as they are, run it for a good two tanks, mixed hovering forward flight and then pull the plug and see.

Paul.
04-21-2008 01:52 AM
 
 
madmcphil
Heliman
Location: Portsmouth, UK

Reading the plug!

For sure the absolute best way to check a plug is by looking at its colour. Fettle with carb setting very carefully until you get a nice sandy brown colour. If your plug is black and wet you know your rich and if its white and light light brown your too lean. On a gasser 1/8th turn on a needle makes a big difference, so smaller changes are a good idea.

I used to race two stroke motorcycles in the British Champs and my engineer always demanded I do a plug chop before bringing the bike back to the pits. The plug chop gives a perfect reading on the plug when engine is under maximum RPM and load. Granted on a heli this isnt so easy to do. If you can do it, this is the way....

Take the heli off, hover for a while, then free fly around for a bit, put the heli back in a stable over and ram full throttle and pitch, then at max revs, kill the engine (not throttle hold but thottle cut) and autorotate and land. Take the plug out ASAP and you will have a perfect reading of what your engines is doing. Sandy brown is what your aiming for.

I run Castrol TTS (fully synth oil) through my G26 and have done from day one at a mix of 40:1. Its a very good oil.

Hope this helps!

p.s jschenck's plug looks bang on the button for a low performance setting. Little leaner should do no harm for the engine, but dont go much leaner.
08-11-2008 12:22 PM
HOMEPAGE  
 
 
shawmcky
Senior Heliman
Location: Isle of Wight,United Kingdom

NGK Plug Guide

If you look on the NGK web site there is a very useful guide that shows the correct plug colours you should be aiming to achieve.
This guide can be used for any make of plug.
08-12-2008 01:17 PM
 
 
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Gasser Model RC Helicopters > Plug reading
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