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Wild (possibly heretical) notion

Old 10-20-2007, 10:37 AM
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digital_trucker
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Default Wild (possibly heretical) notion

I just wondered how possible it might be to convert a PAW 03, 049, or 06 to glow? With all the talk about glow-to-diesel conversions, the notion just struck me. At 1.6 oz for the 03 and 2.6 oz for the 049/061, figuring in that conversion should lighten them up even further, it mightn't be such a bad notion at that.
Old 10-20-2007, 11:02 AM
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Jim Thomerson
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Default RE: Wild (possibly heretical) notion

You might talk with PAW about it. Story some years ago in Aeromodeller that they developed a high performance 1/2 A glow engine for an American ARF manufacturer. Suppose the deal fell through. Might be a good time for PAW to introduce a 1/2A glow engine to the market.
Old 10-20-2007, 11:50 AM
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Default RE: Wild (possibly heretical) notion

Depends on the cylinder head setup. Many diesels of this type use a fin jacket that wraps up and over the head and has the contra piston threads in it. Very few use a separate head that screws in or down. So at the very least you'd need to make a new fin jacket that incorporates the internal head shape as well as the glow plug threading to take a regular plug. Or a fin jacket that has an open head to allow a Cox head to fit.

For the smaller sizes the hole for the element in a regular plug shape is large enough that it's hard to achieve a proper compression ratio.

So all in all yes it can be done but it would need some fairly major machine work. You couldn't just mod an existing head for them.
Old 10-20-2007, 12:05 PM
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Default RE: Wild (possibly heretical) notion

I've never seen one of those particular PAWs in person, so I don't know how the head attaches. Obviously the best bet would be to use a turbo plug instead of a regular short plug. Depending on how the thing goes together it should be a fairly simple matter of just making a head (and shims).
Old 10-20-2007, 12:30 PM
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Default RE: Wild (possibly heretical) notion

For a time, PAW DID offer glow versions of their 1.49 and 2.49 engines. These were not successful, and were soonn dropped from sale. I have one of the 2.49 glows (obtained very second hand) and while it starts and runs well, it has very little power in comparison to similar glow 15s such as OS , Enya and ASP. I suspect that this experience may make PAW reluctant to dip their feet into the glow market again-but there's no harm in asking.
I have all the Aeromodellers right up to the last one produced (before AMI took it over) and I did not recall any mention ever being made of a high performance glow 049 being developed by PAW. Tony Eifflander DID produce a few tuned twin ball raced 80 diesels for his own use-for attempts on the UK 1/2A C/L speed record.

'ffkiwi'
Old 10-20-2007, 12:51 PM
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Default RE: Wild (possibly heretical) notion

DT, that's a pretty cool idea. I'll have to take a look at my .03 and see how difficult it would be. I imagine that the process would be something like Bruce says. You'd be better off to make a boring tool with a combustion chamber shape in the end. Or would that be called a reamer?
Old 10-20-2007, 02:00 PM
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digital_trucker
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Default RE: Wild (possibly heretical) notion

pt - all depends on how the head is, I guess. If the head is seperate from the cylinder it should just be a matter of a replacement head (using a turbo plug, of course). Maybe you could post some pics of how that lil' sucker goes together?
Old 10-20-2007, 03:32 PM
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chevy43
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Default RE: Wild (possibly heretical) notion

Ok here it goes: WHY!!!!! They run great as diesels!!! They swing nice big props too. As much as I like to modify I still have to tell myself "DON'T FIX IT IF IT AINT BROKE"

Heresy! Heresy! Get me a stake and a pile of wood!!!!
Old 10-20-2007, 04:36 PM
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Default RE: Wild (possibly heretical) notion

If they are iron / steel engines, you'll probably just end up with a 1/2A clunker on glow fuel.
Old 10-20-2007, 05:28 PM
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Default RE: Wild (possibly heretical) notion

..it was just a thought...

cp - aren't Cox engines iron engines? Well, steel anyway...

I just had a notion they might turn faster for alla youse go-fasters out there...besides, I still think PAW would be a good candidate to fill the gaping hole in the 1/2A arena

YES durnit, I want a REAL 1/2A modern engine. There's just something magically delicious about .049 displacement. I'm going off to eat my lucky charms and hide from chevy.
Old 10-20-2007, 05:34 PM
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Default RE: Wild (possibly heretical) notion

They are iron and steel. The porting is good enough for diesel but not very good for glow. The extra heat generated by glow fuel doesn't have a direct path to travel and in my opinion that is a problem. It would be possible to do, but I don't think it would work out that well.

For those that are not familiar with diesels built as diesels they typically have an extra long cylinder liner at the top, well past the top of the piston. This is to allow the contra piston to be fitted and seal well, no o-rings needed. In the case of the PAW 55 and 80 the outside of the cylinder is threaded and the cooling fin "head" unit screws onto the cylinder. A glow head to replace the contra would have to be made of steel.
Old 10-20-2007, 05:54 PM
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Default RE: Wild (possibly heretical) notion

Here's some diesel engine soft porn for you guys.
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Old 10-20-2007, 06:57 PM
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Default RE: Wild (possibly heretical) notion

Oh well, was just a thought...
Old 10-20-2007, 07:03 PM
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Default RE: Wild (possibly heretical) notion

OOOOOOHhhhhaaaaa, the wet slippery insides of a PAW 55!!!! I love it!!!
Old 10-20-2007, 07:28 PM
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Default RE: Wild (possibly heretical) notion

She's actually an 80. She not a, uhm, virgin. She's been around, so to speak, before she found me. Runs well and smells nice. I just got her an accessory, a muffler to quiet her down to keep the neighbors from talking about what goes on around here.

If my fiancee was reading this, I'd be slapped right about now. But, she let's me spend some time on engines every now and again so I can't complain.
Old 10-20-2007, 08:35 PM
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Jim Thomerson
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Default RE: Wild (possibly heretical) notion

ffkiwi, there was a two part article on a visit to the PAW plant. I think it was in the last year or so that Aeromodeller was independent. I will have to look around in the shop and find mine. I think the mention of the glow engine was in the second part. Don't recall if there was a picture.
Old 10-20-2007, 08:58 PM
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Default RE: Wild (possibly heretical) notion

Uh huh. I've got to check the port timing on mine. Personally, I've got no problem at all modding a steel cylinder. Good thing I'm far enough away from Chevy he can't slap the back of my head for saying that.[sm=lol.gif]
Old 10-20-2007, 09:04 PM
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Default RE: Wild (possibly heretical) notion

In reply to Digital Trucker, the Cox engines' piston is reasonably light because of the ball socket design. With a conventional wrist pin type steel piston, I don't think you can make the piston as light as the ball socket type, [which really hurts rpm potential]. The glowplug would really need to be countersunk deeply, the tool to wrench it would have to be thin.
Old 10-20-2007, 09:32 PM
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Default RE: Wild (possibly heretical) notion

I don't care if you could convert any diesel to glow - youse guys will never get your grubby paws on my PAWs!

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