JT-8D Hush Kits

From:         lchiluku@ucsd.edu (R. & L. Chilukuri)
Organization: Univ of California at San Diego
Date:         17 Aug 95 04:58:54 
Followups:    1 2 3
Next article
View raw article
  or MIME structure

I am interested in information regarding JT8D hush kits. I've summarized
what little I know, together with questions that are intended to
stimulate discussion -:)

1. The JT-8D is a 1.7:1 bypass ratio engine and extremely noisy when
compared to today's high-bypass engines (5:1). Is the noise generation
predominantly due to the turbomachinery? or jet exhaust? or in the inlet?
What is the character (spectrum) of the JT-8D noise when compared to other

2. JT-8D's are installed on B737s, DC8-?, MD80s. ... and ??

3. The MD80s are extremely noisy during takeoff, but are acceptable during
approach and landing?

4. MD80s have been banned from John Wayne (Orange County) and in Switzerland
because of noise issues.. true?

5. P&W has kits available to reduce noise -- fixes within the turbomachinery
and a forced mixer. But P&W kits do not reduce noise sufficiently .. (true?
false? partly true?)

6. Nordam has a kit that includes a forced mixer to entrain freestream air,
in addition to an ejector?? I know very little about this design..

7. Nordam successfully meets Stage 3 noise regulations ????

8. Nordam's hush kit was not to blame in the recent grounding of B737s in
New Zealand.

9. What are the other competing hush kits and howe do they work?

10. What is the market for hush kits. Is it true that American is furious
with McDonnell Douglas because of all the noise MD80s that they are saddled
with (how many?).

11. What are the takeoff gross weights at which the various competing hush
kits are effective?

and on and on and on...

As you can see, I would appreciate discussion and any intelligence that you
guys can offer

Thanks in advance

Krish Chilukuri