kbuf737
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

JT8D On Takeoff

Wed Feb 18, 2004 10:53 am

Question on the JT8D during takeoff.

What is that common popping noise one hears during take off of any aircraft powered by JT8Ds. I notice it on 727s 737 Classics and DC9s.
The tower? Rapunzel!!!!!!
 
chdmcmanus
Posts: 372
Joined: Wed Mar 21, 2001 12:53 am

RE: JT8D On Takeoff

Wed Feb 18, 2004 11:15 am

That's the rubber bands between the squirrel wheel and turbine snapping under the stress.

Sorry, I couldn't resist.

ChD  Laugh out loud
"Never trust a clean Crew Chief"
 
kbuf737
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

RE: JT8D On Takeoff

Wed Feb 18, 2004 11:20 am

gotta love early technology.
The tower? Rapunzel!!!!!!
 
Air1727
Posts: 318
Joined: Mon Aug 25, 2003 10:57 am

RE: JT8D On Takeoff

Wed Feb 18, 2004 12:49 pm

Pressure differential between the high pressure air surrounding the exhaust and the low pressure high speed air on exit. During high end thrust, the boundary disturbance becomes so high you hear anomolies like popping or snapping sometimes. With higher bypass powerplants, the bypass/exhaust air mixture is more pronounced causing less disturbance.
In the Alaska bush I'd rather have a two hour bladder and three hours of gas than vice versa.
 
sovietjet
Posts: 2546
Joined: Sat Mar 15, 2003 12:32 am

RE: JT8D On Takeoff

Thu Feb 19, 2004 7:55 am

Not just JT-8s. Listen to a Tu-134 with the D-30SeriesII engines takeoff.

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