Airliners-India

Spiderguy252 · Posted: Sat Oct 09, 2010 9:00 pm Post subject: Rear Half of 732 Fuselages

I've always wondered why the rear half of 737-200 fuselages.....

are always a tad bit on the dirtier side?
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Nimish · Posted: Sat Oct 09, 2010 11:01 pm Post subject:

Looking at the pictures seem like the engines are really inefficient throwing up plenty of unburnt carbon/ oil which goes and sticks/ dirties the a/c behind the engine...
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HAWK21M · Posted: Sat Oct 09, 2010 11:25 pm Post subject:

The B732 uses Bucket type T/R mounted at an Angle to the Engine Aft.
This causes exhaust airflow when T/R is deployed to strike the Aft areas of the Fuselage.If not regularly cleaned,will tend to look dirty.
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iflytb20 · Posted: Mon Oct 11, 2010 11:35 am Post subject:

Just adding to what MEL said.

You can see how much the reverser buckets angle towards the fuselage.
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iflytb20 · Posted: Mon Oct 11, 2010 8:05 pm Post subject:

Just adding a bit more to my reply Wink

The 732s had/have what are called "Hot Reverser". In such a system, it is the exhaust which is deflected to provide deceleration. Add to that the fact the the low bypass JT8Ds were not the "cleanest" engines around in terms of exhaust gives us the soot type accumulation on the aft fuselage.

Modern day planes have "Cold Reverser". In in it is the fan air and not the exhaust air which is deflected to provide deceleration.

A bit of a trivia about the development of the 737-100s and -200s. When they were designed, they took the clamshell type reverse thrust straight from the 727. The clamshell type reverser deflect the exhaust vertically up and down. Now in a 727 the engines sit at a higher height and had no problems in using them. But when they fitted them on to the 737s, they had an "exciting" result. When activated, the reverser tended to lift the plane off the runway [as the engines sat a LOT closer to the ground] and there by reduced wheel brakes.

Now as the 737 was not expected to do vertical takeoffs and landings, it was back to the drawing board as far as the reverser were concerned. Finally they came up with the bucket type reverser in which the airstream is deflected by 35 degrees from the vertical. Not only did this prevent the "harrier type landings" but also reduced the chances of FOD.

PS: I think i should shut up now Razz

PPS: I hope this helps Wink

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sumantra · Member Joined: 28 Oct 2007 Posts: 4685 Location: New Delhi

Wow - fantastic explanations with a nice pic!
Thanks a lot, Raj!
Cheers, Sumantra.

Spiderguy252 · Posted: Tue Oct 12, 2010 11:15 am Post subject:

Thanks for the info and the pic, Raj.
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Yeah.

HAWK21M · Posted: Tue Oct 12, 2010 7:38 pm Post subject:

http://www.youtube.com/watch?v=sdVFVGom7es&feature=related

http://www.airliners.net/aviation-forums/tech_ops/read.main/196193/
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ALT STAR · Member Joined: 24 Dec 2009 Posts: 70

Nice pic of the buckets there ...
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HAWK21M · Posted: Wed Mar 16, 2011 11:31 pm Post subject:

Theres a long story to why the angle of TR deflection was chosen too.

Earlier the Buckets were mounted Vertically to open in the 12 Oclock & 6 Oclock positions,however the lower thrust was striking the ground & lifting the MLG off the ground so invariably contributing to reduced braking efficiency hence the tilt was introduced.
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rutvij · Posted: Fri May 20, 2011 12:10 am Post subject:

Wonderful Info there, iflytb20 and MEL. Now that i have started reading about it, its all going in! Smile

Thanks!

HAWK21M · Posted: Wed Sep 26, 2012 4:49 pm Post subject:

http://www.b737.org.uk for great stuff on the type.
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