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Thread: Effect of the loss of Glycol?

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    Default Effect of the loss of Glycol?

    Could someone please explain to me the result I would expect on a Spitfire Merlin engine following the loss of glycol? Being a coolant, would I be correct in assuming that loss of glycol would lead to the engine overheating and seizing?

    In an incident I'm looking into, a pilot returned to base with a glycol leak. He got down again okay, but the aircraft stopped in the middle of the runway, blocking it for other pilots.

    Thanks
    Steve
    41 (F) Squadron RAF at War and Peace, April 1916-March 1946
    http://brew.clients.ch/41sqnraf.htm

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    Hi Steve,

    You are correct in your assumption that loss of glycol would result in the inline Merlin overheating. Glycol was probably used as a coolant because of its anti-freeze properties.

    Infact ester glycol IIRC is the coolant pumped around the LRUs in the AI 24 radar in use today.
    Per Speculationem Impellor ad Intelligendum

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    Hi Andy

    Thanks for your prompt reply. Much appreciated.

    Regards
    Steve
    41 (F) Squadron RAF at War and Peace, April 1916-March 1946
    http://brew.clients.ch/41sqnraf.htm

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    Glycol was used because of its low freezing temperature, high specific heat (ability to remove heat per pound of Glycol pumped around) and its lubricating properties. It is usually a mixture of pure Glycol and water.

    To expand a little on Andy's response: the exact effect would depend in part on the size of the leak. A pin-hole would produce a gradual loss of coolant, and a gradual increase in operating temperatures. This would suddenly go critical once the coolant started to boil, with a rapid temperature increase leading to the engine seizing. A large leak, like a large piece of flak through a cooler, could result in the engine seizing within seconds.

    An added risk with any Glycol leak is a potential for engine and engine bay fires. This results from the engine bay temperatures increasing, plus the possibility that atomized Glycol, from a pin-hole leak or from boiling off coolant, can be ignited when you get just the right ratio of Glycol and air, with little or no water present. I've seen this go off like a bomb in mobile equipment fires (my day job).

    Before anybody panics about the Glycol in their AI24 exploding, I should point out that today there are fire-proof Glycols available. Glycol now comes in phospate bases or ethylene bases, one of which can even be used to put out fires (can't remember which is which at the moment). This is a fairly recent development (last 30 years or so). I believe most automotive applications today still use the cheap, burnable stuff.
    Last edited by Bill Walker; 3rd August 2008 at 17:48. Reason: added last para

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    Hi Bill

    Thanks for your detailed reply.

    Considering your day job, I'll stick to my aerospace contracting, a nice desk-job away from the dangers of anything but the boss exploding!! :-)

    Steve
    41 (F) Squadron RAF at War and Peace, April 1916-March 1946
    http://brew.clients.ch/41sqnraf.htm

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    But Steve, then you miss all the romance and glory! I'm off tomorrow to look at a freshly burnt manure spreader, on top of a large manure pile, in Arizona. Forecast highs of 106F, and rain.

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    Okay, we're getting way off topic here and risk Ross killing this thread but, come on, you've come this far - tell us what you do for a living!
    41 (F) Squadron RAF at War and Peace, April 1916-March 1946
    http://brew.clients.ch/41sqnraf.htm

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    Ethylene glycol, that sounds more like it, thanks Bill. It's been a while since I've worked on the ADV (F.3)
    Per Speculationem Impellor ad Intelligendum

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    Steve - check your inbox.

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