User avatar
Faro
Topic Author
Posts: 1491
Joined: Sun Aug 12, 2007 1:08 am

Garrett TFE731 Was Already A GTF 37 Years Ago?

Thu Jun 25, 2009 11:35 am

Off the Wiki, the Garrett TFE731 introduced on Learjets and Falcon in 1972 was a Geared Turbofan design. My question is why was it the only one? Or was this first GTF implementation much less attractive/efficient than what PW is proposing with their PW1000G? It seems strange that the benefits of GTF were already available 37 years ago but were only adopted on one (very highly successful) engine...

Faro
The chalice not my son
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: Garrett TFE731 Was Already A GTF 37 Years Ago?

Thu Jun 25, 2009 1:42 pm



Quoting Faro (Thread starter):
My question is why was it the only one?

I'm not sure why it didn't show up on other biz-jet engines. Small jets tend to have lower bypass ratios, where the GTF advantage isn't as large, so it's easier for a non-GTF to compete with a GTF. It's the diameter mismatch between the fan and the turbine that causes the fundamental problem that the GTF is trying to resolve. On a biz jet engine, that mismatch isn't near so bad.

Quoting Faro (Thread starter):
Or was this first GTF implementation much less attractive/efficient than what PW is proposing with their PW1000G?

I would hope the efficiency is better on the PW1000G because of the higher bypass. However, the major achievement of what Pratt has done is the scale up. Gearboxes at the biz jet size aren't really any more challenging that gearboxes on turboprops, which have been around for a very long time. It's the scale-up to the power levels required for modern turbofans that's been the challenge, and has consumed decades of research at Pratt.

Tom.
 
trex8
Posts: 4577
Joined: Sat Nov 02, 2002 9:04 am

RE: Garrett TFE731 Was Already A GTF 37 Years Ago?

Thu Jun 25, 2009 7:45 pm



Quoting Faro (Thread starter):
Off the Wiki, the Garrett TFE731 introduced on Learjets and Falcon in 1972 was a Geared Turbofan design. My question is why was it the only one? Or was this first GTF implementation much less attractive/efficient than what PW is proposing with their PW1000G? It seems strange that the benefits of GTF were already available 37 years ago but were only adopted on one (very highly successful) engine...

I'm no engineer but everything I have ever read about the history of GTFs says it was all about getting the gearboxes reliable enough
 
Fly2HMO
Posts: 7207
Joined: Sat Jan 24, 2004 12:14 pm

RE: Garrett TFE731 Was Already A GTF 37 Years Ago?

Fri Jun 26, 2009 7:11 am



Quoting Trex8 (Reply 2):
everything I have ever read about the history of GTFs says it was all about getting the gearboxes reliable enough

and light enough... and not explosive...
 
User avatar
Faro
Topic Author
Posts: 1491
Joined: Sun Aug 12, 2007 1:08 am

RE: Garrett TFE731 Was Already A GTF 37 Years Ago?

Fri Jun 26, 2009 10:51 am



Quoting Tdscanuck (Reply 1):
I'm not sure why it didn't show up on other biz-jet engines. Small jets tend to have lower bypass ratios, where the GTF advantage isn't as large, so it's easier for a non-GTF to compete with a GTF. It's the diameter mismatch between the fan and the turbine that causes the fundamental problem that the GTF is trying to resolve. On a biz jet engine, that mismatch isn't near so bad.

Thanx for the input; I guess Garrett -now Honeywell- should be commended for their foresight and enterprising design. Given the range of aircraft on which the TFE731 was fitted, I doubt that it was unreliable, too heavy or explosive. Just an innovative, fuel-efficient small fan engine.

Faro
The chalice not my son

Who is online

Users browsing this forum: VIflyer and 24 guests