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New kind of conversion for weed whackers

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Old 02-26-2012, 06:47 PM
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nateprice215
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Default New kind of conversion for weed whackers

Hey:

After months of testing, trial and error, I have finally made my echo 21cc engine run very well on gasoline with a glow plug for ignition. Now, this is not continuous (on board) glow, but the igniter is applied for 10 seconds and removed and the engine runs well.

Iam asking this group if there is interest in buying this type of conversion. The benefit this has over the flywheel and spark ignition is mostly weight (about a pound ), which is significant. You do get some advance in the ignition with the glow, not as much as electronic ignition, but then I don't have to carry an ignition system and battery on board either.

Iam putting a post here to see if there is interest in buying these from me. So far Ihave got this to work well on echos. I am going to be designing the conversion for ryobi or homelite next. I started with the hardest one first since the echos have the angled spark plug.

thanks,
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Old 02-26-2012, 06:53 PM
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Default RE: New kind of conversion for weed whackers

Hi, are you using something different than the gas/glow systems already described herein and using a plug adapter from several sources? I have an Echo 16cc and a Rhino (Cox Beaver) running that scheme. Thanks
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Old 02-26-2012, 07:12 PM
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Default RE: New kind of conversion for weed whackers



Are you running just gasoline/oil or gas/glow? Do you have the glow plug powered during flight or just for starting? Myfuel is 40:1 gas/oil mix (the normalstuffweed whackers drink) and i made a custom glow plug adapter that is only ignited forstarting thanks

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Old 02-26-2012, 07:24 PM
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Default RE: New kind of conversion for weed whackers

Is this a special glow adapter?
What I am asking I guess is it a special depth adapter with a different glow plug to make use of the E85 gasoline available or is it a gas/glow fuel mix system? Do you have any pictures or maybe a video to show us?

John
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Old 02-26-2012, 07:42 PM
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Default RE: New kind of conversion for weed whackers


Quote:
ORIGINAL: nateprice215



Are you running just gasoline/oil or gas/glow? Do you have the glow plug powered during flight or just for starting? My fuel is 40:1 gas/oil mix (the normal stuff weed whackers drink) and i made a custom glow plug adapter that is only ignited for starting thanks

I am using gas/glow, and I have the glow plug powered just for starting. Your system uses 10% ethanol gasoline and no methanol?
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Old 02-26-2012, 07:48 PM
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Default RE: New kind of conversion for weed whackers

That is right, no methanol just gasoline/oil mix at the normal ratio. here is video: http://youtu.be/7GfKySURoeA

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Old 02-28-2012, 05:18 PM
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Default RE: New kind of conversion for weed whackers

Ok, so I guess this is not as popular as I thought it would be. Has this already been done? I thought the only way to make a glow plug work with just gasoline was with constant power to the glow. I guess you could always run gas/glow mixture but then you must still buy the expensive glow fuel. I thought this would generate much more interest.
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Old 02-28-2012, 05:42 PM
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Default RE: New kind of conversion for weed whackers

I am interested, do you have an idea what the conversion "kit" will cost? Thanks.

Sincerely, Richard
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Old 02-28-2012, 05:53 PM
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Default RE: New kind of conversion for weed whackers

The kit is just the adapter machined from 316SS and gasket. You can use your own glow plugs, Irecommend the OS #6 or LC3. Iam charging 50 bux
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Old 02-28-2012, 08:21 PM
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Default RE: New kind of conversion for weed whackers

Do you plan to make other styles to fit engines with the straight plug applications?
There are some engines I have with non slanted plugs. Do these take a different type stainless adapter?
You have tried and recommend the OS #6 and LC3 plugs. Would there be any advantage to using an OS 4 cycle plug, or is it just the higher heat range of the #6 plug that makes this possible?

John
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Old 02-29-2012, 07:17 PM
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Default RE: New kind of conversion for weed whackers

Iactually tried the os "F" plug and it did not work so well. Ibelieve it overheated since it has a nose that stick out into the combustion chamber. That is one difference between gas and glow engines; the temperature. Either that or the fact that it was hitting the piston. Since the os "F"plugs were a little more $, Idecided to make this work for less $.

Idid get the ryobi 31cc to run with my adapter, but it was not optimum, Ithink Iwill tackle the ryobi next. The other neat advantage my adapter has is that it increases the compression ratio since it is displacing more volume than the spark plug it replaces without any machining. Iwill try to post some prop data to support this.

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Old 02-29-2012, 09:21 PM
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Default RE: New kind of conversion for weed whackers

let me know when you get the ryobi adapter to work i would be insteristed in that michael
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Old 03-30-2012, 03:51 PM
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Default RE: New kind of conversion for weed whackers

I'm sure you have a lot of time in designing this adapter. However I think $50.00 is to much to generate a lot of interest. Think volume and lower that price and I think you may generate a lot of interest.
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Old 03-30-2012, 04:34 PM
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Default RE: New kind of conversion for weed whackers


Quote:
ORIGINAL: stgrlee

I'm sure you have a lot of time in designing this adapter. However I think $50.00 is to much to generate a lot of interest. Think volume and lower that price and I think you may generate a lot of interest.
I think perhaps an explanation on how the law of physics is defied, glow plugs need catalytic action (or external power) to keep the element hot. This normally comes from alcohol fuel or an external battery.
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Old 03-30-2012, 08:42 PM
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Default RE: New kind of conversion for weed whackers

Iwould say the energy needed for combustion of gasoline with a glow plug comes from compression and the latent heat of the glow plug coil. Now, if you are running methanol in part, that is a different story. Iam runninga gasoline engine on a glow plug without the mentioned constant external power. About the price, Ishould lower it Isuppose. Iam working on more conversions at the moment.
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Old 03-31-2012, 04:04 PM
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Default RE: New kind of conversion for weed whackers

Lets see if we can explain this a litttle better for you. A glow plug keeps glowing after initial heating because of the catalytic action between the nichrome wire in the element and the alcohol fuel. Similarly between a ceramic element and propane/butane gas.
With standard gasoline there is no catalytic action.
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Old 03-31-2012, 05:38 PM
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Default RE: New kind of conversion for weed whackers

Ithought OS glow plugs (#8, for example) were made of platinum not nichrome, right? Iam running regular gasoline with an OS #8 with no external power.
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Old 04-01-2012, 04:57 AM
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Default RE: New kind of conversion for weed whackers

The catalytic reaction of a glow plug is between the platinum plating on the nichrome glow plug element and the methanol in the glow fuel.

In this case of the original poster, the secret is in using a stainless steel adapter which has very poor heat transfer and the OS #6 - (old OS#3(hot)) glow plug. The glow plug heat is maintained by its relative isolation thermally. A prolonged idle and sudden acceleration may be a different story?


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Old 04-01-2012, 04:46 PM
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Default RE: New kind of conversion for weed whackers

That starts to make sense given thermal conductivity rates.
Missed the bit about stainless steel originally.

http://www.engineeringtoolbox.com/th...ity-d_429.html
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Old 04-01-2012, 05:09 PM
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Default RE: New kind of conversion for weed whackers

About the prolonged idling and sudden acceleration; Ihad good luck so far. Iwill try to make an adapter from bronze and see if the performance is different. Iran it today and it was idling very well. The first run went very bad due to overproping (15x10) then Ireduced the compression ratio and put in a 13x10 and it is humming along.
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Old 04-01-2012, 06:30 PM
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Default RE: New kind of conversion for weed whackers

I once ran a little Fox .15 control line engine on regular gas with 20% Klotz Benol oil. I also used an OS #6. The engine ran fine. It did not die when I removed the glow plug igniter. There was a little drop in RPM though. In flight (it was on an R/C plane) it performed well, but the needle was very sensitive. The engine liked to lean out and die in flight. It would do this with glow fuel as well if I did not set it rich enough of the ground. I venturi on the Fox is too big IMO. Anyway, gas with a glow plug does appear to work. I am just not sure if the OS #6 will last as long on gas as it would on glow.
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Old 04-23-2012, 03:52 PM
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Default RE: New kind of conversion for weed whackers

Here is another video of it installed and running on my tiger 60, Ihave flown twice now and it ran great.

http://www.youtube.com/watch?v=vSzr0EYX7zM


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