Turbines, Turbofans, Turboprops, oh my!

[freightdogfred]

Weeeeellll, actually, the old 707s & DC-8s (sorry I just had to) had Rolls-Royce Conway 43 engines with low-bypass TURBOFAN and JT3C-6/7 TURBOJET engines. Followed by later series with JT3D-7 low-bypass TURBOFAN engines.....and my glasses are not taped - (yet)!

Weeeeeellll, you are correct but incomplete as well...As far as the DC-8 is concerned. The series of DC-8 corresponded to the powerplant, as well as some wing and fuselage changes.

DC-8-10's,20's and 30's- straight pipe JT4A's
DC-8-40's- Rolls-Royce Conway's
DC-8-50's- JT3D
DC-8-60's- JT3D-3 or -7, depending on model
DC-8-70's- CFM-56, which are hi-bypass fan engines.

As far as any shaft inside an engine reaching a core temp of 10,000 degrees, I'm sure NASA would be interested in some of this metallurgy for future use on the shuttle. Methinks maybe a few too many zeroes here.

Good explanations mostly on the turbojet/fan/prop. But what can the resident aces here tell me about a
PROPFAN? (a little different than a "turboprop')

 

[Timebuilder]

I rememeber GE touting the propfan design over a decade ago. I'm not sure whatever happened to it.

Perhaps, like the first Eclipse engine, it didn't meet up with expectations.

 

[Loafman]

Stay away from Garretts. I don't trust anything that you have to back up first to go forward...

 

[Smoking Man]

The RR Dart 532-7r (G-1, YS-11, F-27) is able to get about 525 push form exhaust, 1850 from the prop. The prop is shaft driven but you are not required to turn it on your post flight unless you need to verify that the prop has passed all of the prop locks. There should be a stripe on the hub and the props to show position at about 1 degree blade angle.

The P&W 119B&C that we have on the dorks, The only thing that I can find says "recuperates 100% jet thrust" 2180 SHP. (Free Turbine).

 

[Deftone45075]

Stay away from Garretts. I don't trust anything that you have to back up first to go forward...

I've had a captain who would always give the plane to me with one or both still on the locks, passengers love it when you have to slam it into reverse quickly on the take off roll.

However, they are pretty good when it comes to reliability.

 

[metrodriver]

The modern fan engine gets most of its power out of the fan, like the turboprop out of the propeller, so you can say the fan engine is a truboprop with a big casing around it. And about 15 0r 20 years ago they mounted a fan engine backwards, without the fan shroud on a md80 developement and called it a fan jet, like a turboprop powered md80. The project got halted, but I can't recall why, maybe vibration

 

[Deftone45075]

That would have been interesting to see.

 

[LR25]

Didnt the Convair 990 have a fan on the aft turbine?

 

[metrodriver]

The prototype MD 81 was equipped with a GE unducted fan engine. It had two counterrotating fans with the blades directly attached to the turbine disks, resulting in a very fast spinning fan. It was cancelled because of the high noise levels, but they were predicting a 35% reduction in fuel consumption. To see pictures go to http://www.sukhoi.fsnet.co.uk/md81uhb.htm

 

[Timebuilder]

That's the one.

The TV commercials made the thing sound like the wave of the future. Wonder what it sounded like?