Blast pipe

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Blast pipe

Post  mikero on Mon 18 Jul 2016, 10:19 am

Has anyone tried altering the size or shape of the blast nozzle on their Foden? Mine is not making steam as well as I would like and wondered if there were any 'fixes' out there.

Mike

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Re: Blast pipe

Post  LiveSteam on Mon 18 Jul 2016, 12:14 pm

Mike I dont know how long you've been running your foden but have you checked the chimney is clean, I was gobsmacked at how much crud my agri had around the blast pipe and it made a large difference to the draw once it was all cleaned up.

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Re: Blast pipe

Post  mikero on Wed 20 Jul 2016, 1:47 pm

The chimney is not too bad, I just wondered if the shape of the hole made any difference to the flow of the exhaust. A straight hole would not give a particularly clean flow, whereas a venturi shape might but then how big?

Mike

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Re: Blast pipe

Post  gwr1475 on Wed 20 Jul 2016, 5:35 pm

I have thought about making a bigger one.   Mine does have a very strong blast.

What size is yours?

mark

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Re: Blast pipe

Post  mikero on Wed 20 Jul 2016, 11:58 pm

It's the standard pipe that came in the kit. Some of the locomotive men in the club suggested boring it out and making a series of threaded inserts to find out which performs best.

Mike

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Re: Blast pipe

Post  ejparrott on Thu 21 Jul 2016, 1:34 pm

I use threaded inserts on my engines, and the club engines where I've got my paws on them. Shape wise, they are tapered internally up to the hole which itself is parallel at whatever chosen size. Some people have previously advocated convergent/divergent nozzles, as in taper smaller up towards the top internally, then taper back out again, but they don't work any better and in some cases are worse. Stick with mine or just a plain parallel hole.

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Re: Blast pipe

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