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Author Topic: CO2 motors surgery  (Read 1815 times)
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danmellor
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« Reply #25 on: November 14, 2012, 05:00:39 PM »

Puzzling! If the O ring seal is good, a small dent to the threads shouldn't make any difference. I would try playing around with new O rings and making sure it's all very firmly screwed into position.

Dan.
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GM
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« Reply #26 on: November 14, 2012, 06:12:38 PM »


In line with Dans' thoughts, I would be almost certain that the adaptor is not screwing down far enough to compress the O ring sufficiently.

You can test this by fitting the adaptor to the bottle and making a reference line across the adaptor and the bottle. Remove the adaptor and then remove the O ring. Refit the adaptor. 

The reference line on the adaptor should now no longer line up with the reference line on the bottle. Ie, the adaptor should have screwed on a bit further.
You may find that the screw itself is damaged elsewhere or that the end of the bottle is still slightly swaged out (or in).

Working the adaptor on and off again a few times without the O ring might just polish up the bits on the bottle that are binding. Enough for you to know where to clean them up.

Alternatively, try using TWO O rings??

G.
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Kiwi
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« Reply #27 on: July 15, 2013, 05:12:31 AM »

A question I have seen asked elsewhere but have never seen an intelligent answer to.
 Is it possible to use nitrous oxide bulbs in place of CO2? The replies I have seen just go on about it's dangers etc, this is of not an answer to the question and is akin to teaching your grandmother to suck eggs!
I am well aware of the risks, the same as I am aware of the risks with ether based fuels, petrol fumes, solid fuel rocket motors, lipo batteries, steam engines and every other fuel used by modellers, what I really would like to know is what are the differences between liquid CO2 and liquid N2O when used in a Telco or similar as N2O bulbs are easier to get hold of locally.
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danmellor
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« Reply #28 on: July 15, 2013, 03:18:12 PM »

I remember seeing an article in Aeromodeller saying that it was perfectly possible to use them instead of the more usual CO2. Without driving myself mental trying to find it,(LOTS of mags...!) I don't recall any disadvantages being mentioned... I'd give it a go, if I were you! Keep an eye on lubrication, just as you would with CO2 and let us know the results!!

Cheers,

Dan.
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g_kandylakis
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« Reply #29 on: July 17, 2013, 03:12:24 PM »

There is a very comprehensive book on CO2, written by Klaus Joerg Hammerschmidt, one of the very experts on CO2 motors in Europe. The only drawback, it is written in german... Still a valuable reference...

Published in 1992, it appears to be still available:
https://www.webshop.neckar-verlag.de/index.php?id=3&no_cache=1&tx_nvshop_pi1[obj]=details&tx_nvshop_pi1[prod_id]=98

Anyway, in it it says that N2O has been tested and has given more or less identical results to CO2. Being about 20% more expensive, it makes no real sense using it. There is mention that there are no dangers involved, for health or environment.

In short, it is possible to use it but K.J.H. colud not find any advantage following the test and enquiries he made...

George
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Robmoff
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« Reply #30 on: July 17, 2013, 05:34:02 PM »

A question I have seen asked elsewhere but have never seen an intelligent answer to.
 Is it possible to use nitrous oxide bulbs in place of CO2?

I tried this when Telco motors were current, and I had a use for N2O in a whipped cream maker at home. The results were very similar to CO2; I had the impression that power was very slightly down but duration of run increased, but variation between bulbs of either type was more than the difference between types.
If you have some, give it a try.
Rob
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« Reply #31 on: July 18, 2013, 07:17:01 AM »

Cost would probably be the deciding factor.  CO2 bulbs are not cheap here.  Even paintball canisters seem to be more costly than in other countries.  IIRC, a replacement Soda Stream bottle runs abou 9 Euros.

I'll try to find a distributor for N2O bulbs to compare.

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There is mention that there are no dangers involved, for health or environment.
have to disagree on that.  It is misused due to the euphoric effets it has when inhaled, which can lead to further problems and it has a MAJOR (negative) impact on the greenhouse effect (check on the EPA site) - but let's not get into THAT mess, just use discretion if using N2O

Pete
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Kiwi
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« Reply #32 on: July 19, 2013, 04:00:39 AM »

Thanks for that, it conforms with what I thoughtthe story would be, when I build my next CO2 model I'll try N2O as they are easier to find. Nice to  get an answer that treats us as mature people insread of the usual diatribe
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Pete Fardell
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« Reply #33 on: September 08, 2013, 09:27:55 AM »

Well the problem of the leaking adaptor is now resolved, thanks to Derek Knight! himself. I returned it to him and he sent it back with the end of the thread re-cut, so that it now seals onto the gas bottle perfectly. What's more, as a bonus, he's engraved my name on it. To "deter thieves" he says! Pretty cool, eh?

Thanks Derek!
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Re: CO2 motors surgery
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danmellor
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« Reply #34 on: September 13, 2013, 04:05:48 PM »

Pretty cool indeed! Glad it's sorted out...

Cheers,

Dan.
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