akjetBlue
Posts: 777
Joined: Wed Dec 03, 2003 1:59 am

What Happened To This Engine?

Thu Sep 16, 2004 7:32 am

I was wondering if anyone could shed some light on what happened to the idea of using this engine on civil comerical aircraft? The few people who I talked to and even knew about it said that it was very efficent and quiet. Even Embraer had an aircraft design using an EMB-120 with an extended hull with similar (but smaller) engines on the back positioned in the same manner...


View Large View Medium
Click here for bigger photo!

Photo © Malcolm Clarke



Anyone rememeber this? Any info would be apperciated...

Thanks,
-Philzy
Save a horse! Ride a Cowboy!
 
Klaus
Posts: 20622
Joined: Wed Jul 11, 2001 7:41 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 7:40 am

According to many previous threads on the matter, the UDF program got cancelled due to the end of the oil crisis and due to several technical problems. Safety in case of blade separation and generally excessive vibration and noise seemed to be among those...

The question is if the UDF could even compete against modern high-bypass turbofan engines any more...
 
User avatar
yyz717
Posts: 15689
Joined: Mon Sep 10, 2001 12:26 pm

RE: What Happened To This Engine?

Thu Sep 16, 2004 7:45 am

The UDF engine was test flown on a 721 and the above M80. I also recall reading about some resistance from airlines due to the "propellor look" of the UDF.
I dumped at the gybe mark in strong winds when I looked up at a Porter Q400 on finals. Can't stop spotting.
 
CcrlR
Posts: 2187
Joined: Wed Aug 15, 2001 9:24 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 7:48 am

It's a unducted fan engine. it's like the same thing as putting the blades inside, but they are out too and they counterrotate. Embraer did the same thing too.

here is the same thing with Boeing

View Large View Medium
Click here for bigger photo!

Photo © AirNikon

"He was right, it is a screaming metal deathtrap!"-Cosmo (from the Fairly Oddparents)
 
whitehatter
Posts: 5180
Joined: Sat Jun 12, 2004 6:52 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 7:49 am

Efficient it was not.

The program was abandoned due to the early test data indicating a lot of design work and testing would be needed before anything viable could come of it. Ducted fans are much more efficient at higher speeds.

Boeing (or a related company) also fitted a 727 with a similar engine.
Lead me not into temptation, I can find my own way there...
 
FriendlySkies
Posts: 3540
Joined: Fri Aug 13, 2004 3:57 pm

RE: What Happened To This Engine?

Thu Sep 16, 2004 9:43 pm

The program proved to be too expensive, the engine was too loud (louder than a turbofan if you can believe it), and passengers get freaked when they see a prop...why, I don't know, but props have some magical ability to scare passengers.
 
User avatar
Luxair
Posts: 836
Joined: Tue Jan 30, 2001 12:17 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 10:34 pm

Just a question who came up in my mind, wasn't there
a Russian built Aircraft using such a kind of counterrotating
engines, I remember that I've seen it a few years ago but can't remember the details anymore, maybe somebody knows more about?
 
boeingnut
Posts: 390
Joined: Tue Oct 30, 2001 5:46 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 10:45 pm

You're probably thinking of the Bear. Big Soviet turboprop bomber, used four engines, each with two counterrotating propellers. Thing was fast for a prop plane. It was meant to be the Soviet equivilent to the B-52
Excuse me, but what does God need with a starship?
 
User avatar
Luxair
Posts: 836
Joined: Tue Jan 30, 2001 12:17 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 10:59 pm

Boeingnut, you're right regarding the "Bear" but it wasn't that plane. The one I mean is more recent must be in the 90's!!! It was a high wing design as the IL-76 but a lot smaller and if I'm remember correct than it was more like a regional jet let's say more the size of a RJ-100 but than with only 2 engines instead of 4. I will try on Google to find something and let you know.
 
User avatar
Luxair
Posts: 836
Joined: Tue Jan 30, 2001 12:17 am

RE: What Happened To This Engine?

Thu Sep 16, 2004 11:25 pm

Ok, I found something about, the plane I mean, is an AN-70
with 4 counterrotating engines, thus I have to correct myself on the fact that it was a 4 engined AC and not a 2 engined one  Smile/happy/getting dizzy The AN-70 is a prop driven one and the above mentionned ones are Jet driven, is that correct?
 
User avatar
rg828
Posts: 568
Joined: Sun Jan 25, 2004 5:12 pm

RE: What Happened To This Engine?

Thu Sep 16, 2004 11:47 pm

Even Embraer had an aircraft design using an EMB-120 with an extended hull with similar (but smaller) engines on the back positioned in the same manner...

Its actuall the CBA-123, jointly developed by Embraer and FMA of Argentina.


View Large View Medium
Click here for bigger photo!

Photo © Malcolm Clarke



Its just a normal pair of Garret turboprops in pusher configuration, not a UDF.

RG
I dont know the key to success, but the key to failure is trying to please everyone
 
BR715-A1-30
Posts: 6525
Joined: Thu May 30, 2002 9:30 am

RE: What Happened To This Engine?

Fri Sep 17, 2004 3:40 am

The Engine was called the GE-36 It was scrapped before it even had a chance to be ordered. Another project off the drawing board.
Puhdiddle
 
RareBear
Posts: 540
Joined: Thu Jan 29, 2004 4:11 am

RE: What Happened To This Engine?

Fri Sep 17, 2004 4:05 am

Lockheed flew a Gulfstream GII in 1987 with an unducted propfan engine mounted on the left wing, with a counterweight on the right. It was a test program to develop the 6-blade Dowty propellor for the C-130J program.
Illegitimus non carborundum
 
Areopagus
Posts: 1327
Joined: Thu Sep 20, 2001 12:31 pm

RE: What Happened To This Engine?

Fri Sep 17, 2004 4:13 am

Its just a normal pair of Garret turboprops in pusher configuration, not a UDF.

Well, what distinguishes a turboprop from a UDF? The swept scimitarlike blades? New C-130s have them. Blades driven directly off the turbine without gearbox? The Pratt competitor to the GE-36 had a gearbox.
 
keesje
Posts: 8865
Joined: Thu Apr 12, 2001 2:08 am

RE: What Happened To This Engine?

Fri Sep 17, 2004 4:16 am

Heavy construction behind hot combustor, hot air exhaust around the blade angle adjustment mechanisms ... complex

A fan in front of the hot section would provide compressed cool air around the combustor, even if the plane is on the ground, maybe not a bad place after all..

 Smile
"Never mistake motion for action." Ernest Hemingway