Ok, I made my glow plug but I used a auto glow plug instead of a model plug. on straight 2 cycle mix the motor would run but not good. On haft 2 cycle and haft 15% nitro, motor ran good except it seemed like it would lean out after 3 seconds at full throttle, tried adjusting carb I"ll try some of your brews next.

Hi, Thanks for the offer! Yes I'd love to see the file. I have a TurboCAD program I am learning on I think can open Autocad. Send it to [email protected] I'll watch for it. You and your family have a Merry X-mas. Chris

WVARN, Every single cylinder engine will go through two resonance phases. The first one always seams to be around 3000-4000 rpm range. If you have a battery powered ignitoin with fixed timing you could test the engine at different timing settings for smoothest operation in your bad vibration rpm range. Then check your timing with a degree wheel. That should give you an idea if the timing on gas/glow is causing your problem. One other thing is that most all these two cycle engines dont have enough counterweight. One manufacturer uses tungsten added to the counterweights to help smooth the engine vibration. I dont know if when you were testing with ignition if you were using the flywheel and mag. The heavy flywheel will smooth out power pulses from the engine and in some cases its used to help balance the crankshaft.

BME,

Thanks for the comments. The Stihl didn't have the flywheel. I have a EI unit without the Syncrospark so I'll try your suggestion. As far as the counter balance weight is concerned is there any way to determine how much under weight it might be? If I installed a 3"dia X 1/2" piece of aluminum on the prop adapter and then removed material on the side opposite from the crank counter weight would this help? Any comments would be greatly appreciated.

Will

It might but it could also make it worse. The weight needs to be in the counterweight as close to the centerline as possible. This is why double counterweights are better than cantilever crank types. You can drill hole in the counterweight with a carbide bit and press in a plug of tungsten to increase the counterweight. The tungsten weighs about three times as much as the steel. If you dont like it drill out the tungsten and replace it with steel. Nothing to loose but time. Also place the tungsten as close as you can to the outer edge of the counterwight 180 degrees from the crankpin for maximum effect. You can press apart the crankshaft weigh everything and due the math to determine the amount of counterweight needed. Its a real pain in the butt and not any better than a little trial and error since its pretty close to where it should be.

Av8tor1977, is this your current mix - 1 part 10% oil & 10% nitro glow fuel to 2 parts high test gasoline, and with this mix did you make any carb mods? There is a lot of info. on this thread so maybe I missed something. I using a 45cc homelite and if this works out I will try it on a craftsman 55cc. Thanks

Hi,

Yes, that's the mix we are using. As far as the carb, the answer is "it depends". Some carbs will run rich enough with no modifications other than opening the mixture screws a bit; usually a half turn or so. Some carbs don't want to get rich enough unless you raise the lever for the metering diaphragm just a touch. Also note that we are using a good quality four stroke glow plug.

Good luck and have fun,
AV8TOR

Thanks

Let me know how that Homey 45cc turns out. I have one that I haven't converted yet...

Thanks,
AV8TOR

BME,

When you say that they are close, do you think that it is more or less than 10 grams? I don't mind experimenting, just looking for a starting point.

Thanks,

Will

av8tor1977, I did a test run the homey with a mix that is as close to yours as I can get for now. I dont have any 10 10 glow fuel. I used 16% oil and 33% nitro. mixed 107oz of gas 21oz of glow fuel. If I did this right it works out to 31.5 to 1 oil ratio and 7.45% nitro per gal, and your mix is 28 to 1 oil ratio and 5.13 nitro per gal If I did this right???????? The motor ran great once it was adjusted with power on plug. At wot and power off rpms stayed the same , but at idle it would load up after a couple of seconds. My plug coil is incased in a metal shell so maybe it cant hold the heat at low idle? But does that mix sound right?

hey guys. I just stumbled in here and found this thread. I have converted a 45 gas to glow and it runs great (better than it ever did on gas). I'm just using straight methanol and synthetic oil in a 20% 80% mix. works a treat. I'm going to cut the oil back to about 16% and give that a try.
Heres a little video that some of you may have seen.
[link=http://www.rcgroups.com/forums/showatt.php?attachmentid=1105340]Glow conversion.[/link]
No Nitro at all (it will stuff your carby diaphragm and valve plate) and only opened the needles about half a turn more than they required for gas. No other carby mods required.

Hi Rev, I'm interested in the moving the Glow plug deeper into the cyl. I believe this would help the low idle also. When you make one would you sell me 1 with a 14 mm metric thread for testing in a Poulan 25CC weed wacker motor? I'll buy it of course and pay the shipping. Have you ever thought of useing 2 glow plugs and seting them like the old MX bikes at a 45 degree angle?

You guys that are running Glow/Gas mixtures and find the Idle falls off...try holding a piece of leather or a leather glove over exhaust outlet. I did and it helped the glow stay there and the idle was just about a tickover at times. TRY IT AND SEE. What we need is a exhaust throttle to do the same thing. Nobody listens though?????????????? Capt,n

I would think a glow plug with more exposure to the fuel and a higher methanol content in the fuel would more advantageous. by utilizing the catalyst effect of the fuel on the glow plug, you could avoid the mechanical nightmare/extra weight and I'm sure, the choking effect of a throttle butterfly on the exhaust.

I should have said exhaust valve like a throttle plate. It would be coupled to the carb to close as carb throttle closes. Remember the old time glow engines had them. Real simple. Capt,n

Wiz310, What type syn. oil are you using?
Mike

Gday Mike. I'm using the coolpower blue. works fine for me.

wiz what did you do to the gas motor you changed to glo
as fare as carb-comp. so-on and ?

Brad

A real simple conversion mate. I took the ignition off of it and opened the mixture screws about half a turn extra. Added a glow plug adapter and a OS number 3 plug and away we go. 80% methanol and 20% cool power blue synthetic oil and she runs great. i know of another one thats been in service for quite a while in an extra 300 and its a powerhouse. Mine is going into a 1/3 Christen eagle (in a couple of days actually) and will be about twice what it requires. Turning a 22x8 at over 7K and developing an estimated 5 HP. I'll have some better figures when I get some gear together to record some parameters and results.
Cheers, Wiz.

Wayne,

Tell me more. Prop size? RPM? Reedie? Exact mix?

Have you posted on the 1/2A forum?

wiz310: Is 20% oil content needed for lubrication in a engine with ball and needle bearings? At 20% I would think that would eqaual out to be 1 quart oil to 4 quarts of methanol. Seems like a lot of oil? I bet the engine runs good though. Regards Capt,n

CaptinJohn, No I dont think it is required, but as it was its first ever run, I thought I would give in and load it up a little with oil, and cut back as required. It does spray a fair bit of oil around while running, but the next few runs I'll cut the oil in the mix back quite a bit.
It runs like a clock. there is a link in one of my earlier posts to a video of it running.
Cheers, Wiz.

Right on mate!! With less oil it may even run better and cleaner and cost less to mix fuel. That was a nice video...I watched it 3-4 times....make sure you got the parking brake on in the truck! Best Regards Capt,n

Well "converts" this is the beginning of a new year and new projects so it's time to go to the drawing board and start new dessign of planes for our "GAS/GLOW" 31 cc engines, well see what I can come with I'm trying to use some foam board with lite ply to make things faster and ligther so wish me good luck and will keep you posted.
Happy New Year and Happy Flying and Landings.
Aero Nut.