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AJCoholic · 03-15-2010, 07:28 AM

I was perusing over at RCU jets forum... there is a thread on the small 4 lbs thurst Jet joe turbine and as usual, the are having issues (how long has this been going on? maybe 6 years now?)

A fellow who had his baby joe running had a flame out, and upon inspection found this:

http://www.rcuniverse.com/forum/m_84...page_22/tm.htm

You have to see post #527, enlarge the photo.

The turbine nut has stretched so its actually an oval! Wild stuff... never have I seen any nut like that before.

AJC

*SpaceCowboy* · 03-15-2010, 11:37 AM

Thanks for the info Andrew.

I guess that nut missed the tempering process.

It is the old story , "you get what you pay for".

.

lilphil26 · 03-15-2010, 12:09 PM

SOOOOOOOOOOOOOOOOOOOOOOOOO glad I bought a Wren instead of jet joe 1400. Im looking forward to the jetcat p20

**Max** · 03-15-2010, 03:45 PM

Scary!

Do you guys think that is metal creep caused by centrifugal force or a softening of the metal due to high temperature?

Jeremy300 · 03-15-2010, 05:24 PM

Quote:

Originally Posted by Max

Scary!

Do you guys think that is metal creep caused by centrifugal force or a softening of the metal due to high temperature?

Quite simply...it is a poor choice of material for the nut.

Jeremy

YoungestPiperCub · 03-15-2010, 10:22 PM

Combination of a material that yields at a lower melting point then that of the exhaust. One it was softened the metal would start to stretch the further it stretched the bigger the force the worse it gets.

Guest · 03-15-2010, 10:24 PM

Good think I'm not putting that in my Firebird, the fun police might get upset..... oh wait, it's Jet Joe, they don't produce squat for thrust, might be ok, even though they're a proven timebomb

Guest · 03-15-2010, 10:46 PM

How hot would that be getting?

Guest · 03-15-2010, 10:47 PM

Quote:

Originally Posted by can773

How hot would that be getting?

In a Jet Joe it's anyone's guess......... In a proper running turbine, that section should probably not ever exceed 800*C

Guest · 03-15-2010, 11:41 PM

Thats what I thought, I wonder if they just used a low alloy carbon steel...that would not be very good

Should be high nickel, like Inconel, Incoloy...maybe a Titanium or some stainless varieties would be good too.

He's lucky there must not be much axial load or that would have went bye-bye

03-15-2010, 07:28 AM	#1
AJCoholic RCC Supreme Contributor I am: Andrew Coholic Join Date: Sep 2002 Location: Timmins, Northern Ontario Radio of choice: JR 12X, 28X Feedback: 47 / 100% Posts: 12,277 Total Props: 61	wow, you have to see this turbine nut pic... Remove this ad - become a site supporter! I was perusing over at RCU jets forum... there is a thread on the small 4 lbs thurst Jet joe turbine and as usual, the are having issues (how long has this been going on? maybe 6 years now?) A fellow who had his baby joe running had a flame out, and upon inspection found this: http://www.rcuniverse.com/forum/m_84...page_22/tm.htm You have to see post #527, enlarge the photo. The turbine nut has stretched so its actually an oval! Wild stuff... never have I seen any nut like that before. AJC __________________ Andrew Coholic -MAAC #26287L 1/2A to giant scale, IMAC, SAM, R/C sport, turbine jets, Heli's... if its got a wing or two and an engine - I like it!
	.

03-15-2010, 11:37 AM	#2
SpaceCowboy ~~BANNED PEOPLE~~ I am: Mike B. Join Date: Nov 2002 Location: Brentwood , Ontario Radio of choice: FAVOURITE - JR X9303 # of RCs: 7 Feedback: 2 / 100% Posts: 1,517 Total Props: 2	Re: wow, you have to see this turbine nut pic... Thanks for the info Andrew. I guess that nut missed the tempering process. It is the old story , "you get what you pay for". .
	.

03-15-2010, 12:09 PM	#3
lilphil26 RCC Expert Contributor I am: The cookie monster Join Date: Oct 2008 Location: Whitby, ont Radio of choice: Futaba baby!!! # of RCs: 911 Feedback: 8 / 90% Posts: 764 Total Props: 7	Re: wow, you have to see this turbine nut pic... SOOOOOOOOOOOOOOOOOOOOOOOOO glad I bought a Wren instead of jet joe 1400. Im looking forward to the jetcat p20 __________________
	.

03-15-2010, 03:45 PM	#4
Max Administrator ★ Site Supporter ★★ Administrator ★ I am: Max P. Join Date: Feb 2007 Location: Aurora, Ontario Radio of choice: JR and Spektrum Feedback: 77 / 100% Posts: 19,799 Total Props: 232	Re: wow, you have to see this turbine nut pic... Scary! Do you guys think that is metal creep caused by centrifugal force or a softening of the metal due to high temperature?
	.

03-15-2010, 10:22 PM	#6
YoungestPiperCub RCC Supreme Contributor I am: Kevin King Join Date: Apr 2007 Location: Waterloo, Ontario Radio of choice: 12x # of RCs: ??? Feedback: 17 / 100% Posts: 2,123 Total Props: 44	Re: wow, you have to see this turbine nut pic... Combination of a material that yields at a lower melting point then that of the exhaust. One it was softened the metal would start to stretch the further it stretched the bigger the force the worse it gets. __________________ Kevin King MAAC - 76804 ---------------------------------------------------------------------- -----Youtube Channel-----
	.

03-15-2010, 10:24 PM	#7
Guest Guest Join Date: Sep 2002 Feedback: 0 / 0% Posts: 0 Total Props: 57	Re: wow, you have to see this turbine nut pic... Good think I'm not putting that in my Firebird, the fun police might get upset..... oh wait, it's Jet Joe, they don't produce squat for thrust, might be ok, even though they're a proven timebomb
	.

03-15-2010, 10:46 PM	#8
Guest Guest Join Date: Sep 2002 Feedback: 0 / 0% Posts: 0 Total Props: 57	Re: wow, you have to see this turbine nut pic... How hot would that be getting?
	.

03-15-2010, 11:41 PM	#10
Guest Guest Join Date: Sep 2002 Feedback: 0 / 0% Posts: 0 Total Props: 57	Re: wow, you have to see this turbine nut pic... Thats what I thought, I wonder if they just used a low alloy carbon steel...that would not be very good Should be high nickel, like Inconel, Incoloy...maybe a Titanium or some stainless varieties would be good too. He's lucky there must not be much axial load or that would have went bye-bye
	.

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