Go Back  PPRuNe Forums > Aircrew Forums > Military Aviation
Reload this Page >

Tornado F3 - asymmetric engine configuration ?

Military Aviation A forum for the professionals who fly military hardware. Also for the backroom boys and girls who support the flying and maintain the equipment, and without whom nothing would ever leave the ground. All armies, navies and air forces of the world equally welcome here.

Tornado F3 - asymmetric engine configuration ?

Old 20th Dec 2020, 12:07
  #21 (permalink)  
 
Join Date: May 2006
Location: front seat, facing forwards
Posts: 1,150
Received 9 Likes on 4 Posts
Originally Posted by Buster15
The engine cycle was optimised for fuel efficiency and range. That is why it had the high bypass ratio.
Yes, I know. It was a very focussed aircraft/engine design which showed up when you took it outside its originally intended domain.
just another jocky is online now  
Old 20th Dec 2020, 12:21
  #22 (permalink)  
 
Join Date: Feb 2006
Location: Hanging off the end of a thread
Posts: 30,833
Received 1,714 Likes on 742 Posts
Originally Posted by Peter G-W
I remember starting the APU with a guy deep inside the right hand intake. He came out in far less than 30 seconds and didnít require a ladder
That was always my fear on Jags, I used to let people know in no uncertain terms I was down the intake.
NutLoose is offline  
Old 20th Dec 2020, 13:02
  #23 (permalink)  
 
Join Date: Aug 2015
Location: England
Posts: 342
Received 6 Likes on 6 Posts
Originally Posted by just another jocky
Yes, I know. It was a very focussed aircraft/engine design which showed up when you took it outside its originally intended domain.
That is quite true. However, its inherent design did allow it to become pretty flexible and adaptable to role changes over its 40+ year life cycle.
But the laws of physics will always apply.
Buster15 is offline  
Old 20th Dec 2020, 13:09
  #24 (permalink)  
 
Join Date: Aug 2009
Location: West of Suez
Posts: 335
Received 0 Likes on 0 Posts
Originally Posted by Peter G-W
I remember starting the APU with a guy deep inside the right hand intake. He came out in far less than 30 seconds and didnít require a ladder
Thankfully, it is almost Christmas and somebody will buy me a new keyboard.
AnglianAV8R is offline  
Old 20th Dec 2020, 14:07
  #25 (permalink)  
 
Join Date: Dec 2013
Location: UK
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by just another jocky
Yes.

Never heard of his assertion; I'm not sure there was anything you could do with the RB199 to make it perform better at altitude....other than replace it with a better engine.
There were a number of programmes ongoing throughout the life of the engine to improve performance and reliability. Need to get my post count to 10 before I can post pictures/urls as I found some info about this on Flight Global via the 'Wayback Machine'.
iranu is offline  
Old 20th Dec 2020, 14:27
  #26 (permalink)  
 
Join Date: Dec 2013
Location: UK
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Peter G-W
I remember starting the APU with a guy deep inside the right hand intake. He came out in far less than 30 seconds and didnít require a ladder
He wouldn't have required a ladder coming out the other end either. .
iranu is offline  
Old 20th Dec 2020, 14:49
  #27 (permalink)  
 
Join Date: Feb 2006
Location: Hanging off the end of a thread
Posts: 30,833
Received 1,714 Likes on 742 Posts
Having done a little deep strip on the RB199 you wouldn’t get in the aircraft if you saw the state the innards got to.
NutLoose is offline  
Old 20th Dec 2020, 16:04
  #28 (permalink)  
 
Join Date: Dec 2001
Location: Here 'n' there!
Posts: 566
Received 3 Likes on 1 Post
Originally Posted by Peter G-W
I remember starting the APU with a guy deep inside the right hand intake. He came out in far less than 30 seconds and didn’t require a ladder
Pete, wasn't me down there - coz you are still alive!!!!!

Question? I'm sure the TAT probe was only down the Port intake. Not sure what it fed but why only one? Never thought about that!

Last edited by Hot 'n' High; 20th Dec 2020 at 16:16.
Hot 'n' High is offline  
Old 20th Dec 2020, 18:56
  #29 (permalink)  
 
Join Date: Aug 2015
Location: England
Posts: 342
Received 6 Likes on 6 Posts
Originally Posted by NutLoose
Having done a little deep strip on the RB199 you wouldnít get in the aircraft if you saw the state the innards got to.
You have to remember the the RB199 really was pushing the boundaries of what was possible given the technology at the time and the way the aircraft was being operated. The engine itself is pretty tolerant to the thermal and mechanical loads. And of course there were two of them.
Buster15 is offline  
Old 20th Dec 2020, 20:07
  #30 (permalink)  
 
Join Date: Mar 2010
Location: Along the A43
Age: 57
Posts: 37
Likes: 0
Received 0 Likes on 0 Posts
Left and right hand engines rotated the same way, they need airflow coming in at the optimum angle, which could have been facilitated in one intake, but not so in the other, hence the fences to present the airflow at a better angle (but with some energy losses).
We did not learn in 2 generations of aircraft that you need a convergent-divergent nozzle on a fighter jet's engines to work well at altitude. Think Spey Phantom vs J79 Phantom. RB199 vs anything. Not worth it if you stick to low level, the weight and complexity will not pay off vs the marginal advantage, but as soon as you switch from Norfolk Land Shark to fighter mode, con-di nozzle is the way.
bridgets boy is offline  
Old 21st Dec 2020, 00:48
  #31 (permalink)  
 
Join Date: Dec 2013
Location: UK
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts
Here's the info regarding RB-199 post introduction development:





Iirc the original 'on wing' time was around 100 hours due to the original Mk101 being immature, but that grew considerably throughout the engine programme as the Mk 103/104 came into service and there were some engines which were hitting well over 1000 hours before the GR4 was scrapped. The 1980s XG engines and other varients all contributed to the success of the EJ200.
iranu is offline  
Old 23rd Dec 2020, 12:40
  #32 (permalink)  
 
Join Date: Aug 2015
Location: England
Posts: 342
Received 6 Likes on 6 Posts
Originally Posted by iranu
Here's the info regarding RB-199 post introduction development:





Iirc the original 'on wing' time was around 100 hours due to the original Mk101 being immature, but that grew considerably throughout the engine programme as the Mk 103/104 came into service and there were some engines which were hitting well over 1000 hours before the GR4 was scrapped. The 1980s XG engines and other varients all contributed to the success of the EJ200.
That is really interesting.
Yes the Mk101 had a number of issues. In particular the Oil System which was not all attitude and so for inverted flight, it had a couple of accumulators to maintain oil supply. That was completely revised on the 103. In order to increase on-wing life, some 101's were do- rated.
Certainly the Mk103 was a better engine in most areas but as expected, the equiaxed high pressure turbine blades still suffered from thermal fatigue.
Introduction of the single crystal blades greatly improved reliability.
Nevertheless, the engine was operated for a great deal of the time at its temperature limit due to the high proportion of time spent at low level.
Surprisingly, the GR4 programme did not include any engine enhancements despite the additional weapons capabilities.
Buster15 is offline  
Old 2nd Jan 2021, 15:54
  #33 (permalink)  
 
Join Date: Sep 2001
Location: UK
Posts: 770
Likes: 0
Received 3 Likes on 2 Posts
There was another asymmetric aspect to the Mk 104 engines in the F3 and that was the surge boundaries. At the tested conditions (21 AOA in a turn, and either slam max dry to idle and when just sub-idle reslam to max dry or slam max dry to sub idle, sweep the wings by one angle change then immediately reslam to max dry) for a given standard of DECU software one engine would always surge at a consistently higher airspeed than the other ie. was the 'critical' engine for surge. However, we did see that following one software upgrade (cannot remember which one) the critical engine swapped from one side to the other with no hardware changes inside the intakes at all. I never did hear a convincing explanation for this.
LOMCEVAK is offline  
Old 4th Jan 2021, 20:08
  #34 (permalink)  
 
Join Date: Aug 2015
Location: England
Posts: 342
Received 6 Likes on 6 Posts
Originally Posted by LOMCEVAK
There was another asymmetric aspect to the Mk 104 engines in the F3 and that was the surge boundaries. At the tested conditions (21 AOA in a turn, and either slam max dry to idle and when just sub-idle reslam to max dry or slam max dry to sub idle, sweep the wings by one angle change then immediately reslam to max dry) for a given standard of DECU software one engine would always surge at a consistently higher airspeed than the other ie. was the 'critical' engine for surge. However, we did see that following one software upgrade (cannot remember which one) the critical engine swapped from one side to the other with no hardware changes inside the intakes at all. I never did hear a convincing explanation for this.
How interesting. Can you remember approximately when this was. And was it a repeatable event.
And when you say 'sub-idle' can you recall the actual NH.
And lastly, and I apologise for testing your memory, were both engines pilot levers moved in the same way at the same time.
Thank you and thank you for your post.
Buster15 is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.