YULspotter
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Question About Thrust Reverser Types

Tue Aug 15, 2006 10:56 am

Hello.

Need some help on thrust reversers.

I have seen three different types on commercial aircraft. Two of which I believe I know the names of but not the third one. I did some research but can't seem to find anything.

There's the classic clam shell ...

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Photo © Dan Brownlee



There's the translating cowl ...

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and then there's this one ...

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Can someone help out. Thanks

YULspotter
 
tinpusher007
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RE: Question About Thrust Reverser Types

Tue Aug 15, 2006 11:04 am

I believe the one on the Trent powered A330's are called 'target type' or 'bucket type' reversers. I've heard both terms for this type. They open similarly to the calmshell type, but like the translating cowl type, they only reverse the fan air.
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BH
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RE: Question About Thrust Reverser Types

Tue Aug 15, 2006 1:19 pm

I have also heard the "target type" or "bucket type".I guess as long as it works i'm happy.
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crownvic
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RE: Question About Thrust Reverser Types

Tue Aug 15, 2006 1:28 pm

Although the function is similar to the translating cowl, you forgot to mention the "Cascade" type. This is what is on the later 727's (not re-engined) and many other early generation airliners (BAC-111, Trident, TU-134, TU-154B2, DC-8-50/61).
 
DreamsUnited
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RE: Question About Thrust Reverser Types

Tue Aug 15, 2006 1:31 pm

I have oftentimes wondered what that type of reverser that was too, I am only fermiliar with the cascade and the clamshell ones... nice question.

-Josh

Wait! Is there a difference between the translating and cascade reversers? I though that the cascade's were on most airliners ie the Boeing airliners except the 717...

[Edited 2006-08-15 06:35:48]
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FriendlySkies
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RE: Question About Thrust Reverser Types

Tue Aug 15, 2006 2:24 pm

Quoting Crownvic (Reply 3):
Although the function is similar to the translating cowl, you forgot to mention the "Cascade" type. This is what is on the later 727's (not re-engined) and many other early generation airliners (BAC-111, Trident, TU-134, TU-154B2, DC-8-50/61).

I believe Avon-powered Caravelles with reversers also featured this type.
 
N231YE
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RE: Question About Thrust Reverser Types

Wed Aug 16, 2006 9:18 am

This gets kind of confusing...

I've heard that this was a Target/Bucket:

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That this was a Clamshell:

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Photo © Frank C. Duarte Jr.



That this was a Cascade/Translating Cowl:

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Photo © Normando Carvalho Jr.



And that this was a Petal:

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Photo © Alexander Watts



I've read this in several books on the 737, 727, and even a book on Jet Engines (Modern Aircraft Engines-I believeis the name). But as I have seen on A.Net, the names very widely...
 
jetlife2
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RE: Question About Thrust Reverser Types

Wed Aug 16, 2006 11:19 am

The third type are called "blocker doors".

This can get confusing because there are some engines which use a combination of translating cowl plus blocker doors, in which case the blocker doors are a subassembly not the only element. See here for more detail

http://www.aviationindustrygroup.com/index.cfm?format=1257
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F14D4ever
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RE: Question About Thrust Reverser Types

Wed Aug 16, 2006 11:37 am

Quoting Jetlife2 (Reply 7):
there are some engines which use a combination of translating cowl plus blocker doors, in which case the blocker doors are a subassembly not the only element

The translation of the cowl only exposes the cascade. It does not by itself divert air through the cascade. The blocker doors are the requisite pieces which accomplish the diversion of airflow through the cascade, thereby producing reverse thrust.

So a so-called 'cascade' reverser consists of both the namesake cascade and the blocker doors.

This type of reverser is used with the CF34-8, CF34-10, CF6, and CFM56, among others.
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MesaMXORD
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RE: Question About Thrust Reverser Types

Thu Aug 17, 2006 4:52 am

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On the CF-343B1 (Pictured) the Translating cowl slides back exposing the Cascade Vanes, while the cowl is sliding back it pulls the blocker doors (red arrow) up to divert the fan air.
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YULspotter
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RE: Question About Thrust Reverser Types

Thu Aug 17, 2006 10:24 am

O.K. so this is called a blocker door or petal type of reverse thruster.


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Now I can sleep well at night.
Thanks everyone for helping to clear this up.

YULspotter
 
3DPlanes
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RE: Question About Thrust Reverser Types

Sat Aug 19, 2006 8:58 am

Quoting YULspotter (Reply 10):
Now I can sleep well at night.

Careful now, lest the bogeyman come calling... Cascade reversers use blocker doors as well.

For the Mech types, do petal reversers block the bypass all the way around? It seems like they'd need to or else a sizeable amount of bypass air would still go out the back.

But, if they do, how do they ensure that all the blocked air goes out the open petals? Since (unlike cascade systems) the open petals are small in relation to the intake, it seems like you'd get some air going back out through the fan.

Curious the amount of interest folks have in thrust reversers... Must be the mechanicals and such, like with landing gear.
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Yikes!
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RE: Question About Thrust Reverser Types

Sat Aug 19, 2006 12:11 pm

Missed in the above:

The cascade/sleeve/petal/other types of reversers deflect only high-bypass flow. Core flow continues in the traditional vector. But core thrust on high-bypass engines during landing roll contribute to only about 25% of total engine thrust.

Clamshell type reversers re-direct the total flow of low-bypass engines, are very noisy and are high-maintenance.

High-energy reverse thrust is most effective at high forward speeds. Reverse thrust does not reduce landing roll if used in conjunction with autobrakes. Reverse thrust does reduces brake wear.

Whereas brakes are cheaper to replace than engine parts, I tend to use a deceleration strategy that enables me to clear the runway where I want to, usually resulting in a fixed autobrake value and idle reverse.

For what it's worth.
 
2H4
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RE: Question About Thrust Reverser Types

Sat Aug 19, 2006 1:15 pm



I just wanted to point out just how professional this forum is. The original poster's question is asked and addressed fairly regularly, but rather than scold the new member for not using the search function, a polite and interesting discussion resulted.

Welcome to Tech/Ops, YULspotter....you'll love it here!  Smile




2H4


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HAWK21M
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RE: Question About Thrust Reverser Types

Sat Aug 19, 2006 5:36 pm

Quoting Yikes! (Reply 12):
Clamshell type reversers re-direct the total flow of low-bypass engines, are very noisy and are high-maintenance

The Fact they are used must have some Benifits too.Any list.
regds
MEL
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