User avatar
N328KF
Topic Author
Posts: 5810
Joined: Tue May 25, 2004 3:50 am

GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 12:53 am

With the GEnx and Trent 1700 replacing the CF6 and RB211, respectively, on many civil airframes, what are the chances we will see either of these engines being used for re-engining projects in the place of those two engines, as well as the TF39? Candidates include the KC-10, E-4, C-5, etc. (I obviously don't see them touching SAM 28000/29000.)
When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' -Theodore Roosevelt
 
TheSonntag
Posts: 4303
Joined: Wed Jun 15, 2005 7:23 pm

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 1:07 am

Since B52s still use the TF-33 (JT-3Ds), just like many E3-A Awacs, I really doubt C-5s will be re-engined, as military projects tend to use the "old crap" quite long time (which is great).

But thats just my opinion
 
SATL382G
Posts: 2679
Joined: Sat Aug 14, 2004 12:02 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 2:01 am

Quoting TheSonntag (Reply 1):
I really doubt C-5s will be re-engined,

It's happening as we speak, with CF6 though.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
TheSonntag
Posts: 4303
Joined: Wed Jun 15, 2005 7:23 pm

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 3:42 am

Quoting SATL382G (Reply 2):

Ok, didn't know that. Whats the original engine? JT9Ds? If so, why are they re-engined? Wasn't the C-5 the first airplane ever to use high-bypass Turbofans?
 
whitehatter
Posts: 5180
Joined: Sat Jun 12, 2004 6:52 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 4:13 am

The GENx and Trent 1700 would not be ideal for the existing systems of the C-5. Purely for commonality reasons the CF6 is the ideal powerplant as the TF-33 is a close relative.

The RB211 was originally proposed for the B-52 but nothing came of it, specifically the -535E4 variant from the 757.
Lead me not into temptation, I can find my own way there...
 
SATL382G
Posts: 2679
Joined: Sat Aug 14, 2004 12:02 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 4:15 am

Quoting TheSonntag (Reply 3):
Whats the original engine? JT9Ds? If so, why are they re-engined? Wasn't the C-5 the first airplane ever to use high-bypass Turbofans?

The C-5 has been flying all these years with the TF-39, the first high bypass turbofan. The C-5 is the only airframe to use the TF-39. The TF-39 found more success as a marine powerplant (LM2500) than it ever did as an aircraft engine.

They are being reengined because the TF-39, being on one airframe only, was never seriously developed. The CF6, which sprang out of the TF-39 program, was and is in service on a number of commercial airframes. The benefit of the reengining to the C-5 is more power, better fuel economy, and ease of maintenance.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
whitehatter
Posts: 5180
Joined: Sat Jun 12, 2004 6:52 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 4:36 am

Quoting SATL382G (Reply 5):
They are being reengined because the TF-39, being on one airframe only, was never seriously developed. The CF6, which sprang out of the TF-39 program, was and is in service on a number of commercial airframes. The benefit of the reengining to the C-5 is more power, better fuel economy, and ease of maintenance.

There's also the worldwide availability of a parts bin for the CF6. Being able to source a part quickly in peacetime operations cuts costs down.

There are plenty of civilian operations with CF6 overhaul capabilities worldwide.
Lead me not into temptation, I can find my own way there...
 
GDB
Posts: 12653
Joined: Wed May 23, 2001 6:25 pm

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 4:43 am

I've always been surprised they did not do a CF-6 fit when the C-5B was in production in the 1980's, retro-fitting C-5A's when they were re-winged too.

I guess they needed more airlift quickly, both new production and getting the original C-5A's fixed however.
 
DfwRevolution
Posts: 8572
Joined: Sat Jan 09, 2010 7:31 pm

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 7:39 am

Quoting WhiteHatter (Reply 4):
The RB211 was originally proposed for the B-52 but nothing came of it, specifically the -535E4 variant from the 757.

I believe Boeing also pitched a modernization program with CFM56 re-engine, as well.
 
SATL382G
Posts: 2679
Joined: Sat Aug 14, 2004 12:02 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 12:29 pm

Quoting WhiteHatter (Reply 4):
Purely for commonality reasons the CF6 is the ideal powerplant as the TF-33 is a close relative.

TF-33 is a P&W powerplant and unrelated to the GE CF-6.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
aeroweanie
Posts: 1577
Joined: Fri Dec 03, 2004 9:33 pm

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 12:51 pm

Quoting SATL382G (Reply 2):
It's happening as we speak, with CF6 though.

With the 20-year old CF6-80C2 to be exact...
 
User avatar
RayChuang
Posts: 8004
Joined: Sat Jun 24, 2000 7:43 am

RE: GEnx/Trent 1700 For C-5?

Wed Oct 12, 2005 11:30 pm

If I remember correctly, the engines the C-5's will get are the same engines used on the E-4B and VC-25A: the GE F103 turbofan, essentially a military version of the CF6-80 turbofan used on 767's, 747's and A330's.
 
GDB
Posts: 12653
Joined: Wed May 23, 2001 6:25 pm

RE: GEnx/Trent 1700 For C-5?

Thu Oct 13, 2005 2:13 am

I understood that the TF-39 was a GE product.
 
F14D4ever
Posts: 306
Joined: Sat May 07, 2005 3:20 am

RE: GEnx/Trent 1700 For C-5?

Thu Oct 13, 2005 5:25 am

Quoting RayChuang (Reply 11):
If I remember correctly, the engines the C-5's will get are the same engines used on the E-4B and VC-25A: the GE F103 turbofan, essentially a military version of the CF6-80 turbofan used on 767's, 747's and A330's.

You did well from memory.

FWIW, there are turbomachinery differences between the F103 variants found on the E-4B and VC-25A. The E-4B and the KC-10 have military versions of the CF6-50, which utilizes a 3-stage booster. The VC-25A has an F103-102 which is a CF6-80C2B1, running a 4-stage booster. So while they are all called F103 by the USAF, they're NOT all CF6-80's.

To further discriminate, the C-5M will get a variant with the civilian nomenclature CF6-80C2L1F, which has the Full Authority Digital Electronic Control (FADEC).
"He is risen, as He said."
 
TheSonntag
Posts: 4303
Joined: Wed Jun 15, 2005 7:23 pm

RE: GEnx/Trent 1700 For C-5?

Thu Oct 13, 2005 9:16 am

Are there really differences between military and civilian engines? Obviously there are, but why? To make C-5s more FOD resistant, or are there other reasons?

Is the TF-33 of the Awacs identical with the JT-3D, or are there differences, as well?
 
F14D4ever
Posts: 306
Joined: Sat May 07, 2005 3:20 am

RE: GEnx/Trent 1700 For C-5?

Thu Oct 13, 2005 9:35 pm

Quoting TheSonntag (Reply 14):
Are there really differences between military and civilian engines? Obviously there are, but why? To make C-5s more FOD resistant, or are there other reasons?

In the case of the CF6 / F103 I believe it's entirely a matter of nomenclature.
"He is risen, as He said."

Who is online

Users browsing this forum: No registered users and 14 guests