Maggie Muggs Site

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larry cottrill
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Re: re: Maggie Muggs Site

Post by larry cottrill » Wed Nov 16, 2005 6:26 pm

Zippiot wrote: a wierd thing that i cant explain is that the closer i bring the shop vac to the opening of the jet, the more the flames curl back towards the shopvac. my only explaintion is that the back of the jet is making high pressure from the heat and the shop vac with its high speed moving air is making low pressure. a vacume making a vacume...
Well, it probably isn't quite as simple as that. I think it's more like only a little of the flow is making it through the flameholder, with most of the air just pressurized in front of it. The air is stalled at the flameholder - that is, you don't get more flow, no matter how much pressure you add beyond that point. Instead, the diffuser just fills to overflowing with turbulent, high-pressure air. Then, the air you're driving into it mixes in with the turbulence just inside the intake, and mostly overflows along with it. The speed of the air inside the diffuser is fairly slow and turbulent, so combustion easily forms there. And, yes, once it gets out, it would feel the influence of the flow stream closer to the blower and be pulled in toward it.

Just what you said, I guess, but in more detail (of a mostly speculative sort ;-)

Good observations on your part, though!

Remember that Maggie has the crude flameholder she does precisely because she's supposed to work at the very lowest range of practical flight speeds. Reasonable efficiency is unattainable, and is considered a non-issue in this design.

L Cottrill

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re: Maggie Muggs Site

Post by Zippiot » Thu Nov 17, 2005 6:57 am

i found a nozel (check spelling) for the shp vac, now it shoots out much faster more concentrated air. all i can say is who needs hair on their left arm...or their legs...?

edit: now a few mins later, i realize that there are a few second degree burns on my left hand...
currently on the phone with the doctor
Sailing Student- How do I know if my life jacket is tight enough?
Me- Can you breathe?
Sailing Student- Yes
Me- Then its too loose!

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re: Maggie Muggs Site

Post by Mark » Thu Nov 17, 2005 5:01 pm

I'd be interested to know how the hydrogen manufacture accident came about, did you have it confined in a pipe or large balloon with oxygen or what? It would a good cautionary tale to stress the importance of hearing protection.
Presentation is Everything

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