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Old Jul 29, 2005, 04:43 PM
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JetCat under high G loading!

Hello All,

This is my first post here and I appreciate all of your input. An aircraft we are building now may in the near future use JetCat P80s. These jet engines would be under serious G loading, probably close to 40 to 60 Gs. Is anyone familiar with P80s or know how they would react to this high stress (turbin/fan displacement, fuel issues, etc. )? Thanks for your help!

Slopilot
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Old Jul 29, 2005, 05:32 PM
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Quote:
Originally Posted by slopilotAero
Hello All,

This is my first post here and I appreciate all of your input. An aircraft we are building now may in the near future use JetCat P80s. These jet engines would be under serious G loading, probably close to 40 to 60 Gs. Is anyone familiar with P80s or know how they would react to this high stress (turbin/fan displacement, fuel issues, etc. )? Thanks for your help!

Slopilot
Have you asked JetCat themselves???

Dave
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Old Jul 29, 2005, 06:50 PM
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Yes I have and they have not done tests to that extreme. So it is unknown to them what happens at those levels of stress.

Slopilot
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Old Aug 02, 2005, 08:22 AM
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As I understand it, problems start with some really wacky aerobatics like the chicken flop, and it will kill the engine.
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Old Aug 02, 2005, 08:32 AM
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I'm highly doubtful you could get anywhere near 40-60G's with an airplane without stalling long before or ripping the wings off.
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Old Aug 02, 2005, 08:37 AM
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Well...you could file it from a single block of unobtanium.
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Old Aug 02, 2005, 08:39 AM
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40-60G's?????? err, care to share how you would pull something off like that?
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Old Aug 02, 2005, 10:02 AM
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That is...if you have a file made of HARDENED unobtanium. Otherwise, how else will you do it?
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Old Aug 02, 2005, 10:33 AM
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Quote:
Originally Posted by easytiger
That is...if you have a file made of HARDENED unobtanium. Otherwise, how else will you do it?
Man, you've been diging in the dust of that old ware house waaaaay too long!
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Old Aug 02, 2005, 11:22 AM
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I found some scraps of unobtanium in the loft of the warehouse the other day, but I keep wearing out dremel bits trying to make a really quality toothpick like I wanted.

I do believe that the Jetcat warranty becomes invalid after 30g...at which point the turbine has become a flat circle of metal about 1/16" thick, but you will have to check that with Bob Wilcox or John Redman.
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Old Aug 02, 2005, 02:18 PM
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Wow... Thanks guys for all your sarcasm. However, I understand your assumption that this will be on an airplane. The intention would be to put them on the end of rotor blades and I'm just curious if the JetCat has been tested at these levels. Intuition would tell me it probably wouldn't work but you never know. Thanks for your help!

Slopilot
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Old Aug 02, 2005, 03:46 PM
THAT'S WHY
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That would sound way better than pulse jets.
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Old Aug 02, 2005, 09:12 PM
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Nah, a twin pulsejet helicopter would sound WAY COOL!
Anybody ever do a FF one with jetex on the rotor tips? There was an ARF one back in the Fifties, from england. Totally cool.
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Old Aug 02, 2005, 09:57 PM
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I would think that even if it did run at those speeds, the wear from that much force would cause serious problems with the bearings.
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Old Aug 03, 2005, 08:59 AM
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There was a guy here in OKC that had a Hiller hornet at Sundance airpark. Saw him fire (litterally) up once. He never tried to fly it. Those ramjets were loud.

There is an alternative to stressing the jet cats to a constant 30G's, mount the engines on the fuselage and duct the exhaust to the tips like the Hugges XH-17
http://1000aircraftphotos.com/Contri...lborg/3138.htm

This way you can just gang up more engines as needed for the load you need to lift.

Tom
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