F-35 Cancelled, then what ?
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Chaps it now seems to go up and down 
Quote from the RAF News Feed ... Just published ...
I'm not FJ conversant/experienced ... so just a question of curiosity ...
What is the transition speed tolerance (from Engineborne vertical to Wingborne horizontal flight) for that damn great intake flap before it becomes a huge speed retarding spoiler ... does the intake flap have selective open/close settings or is it either fully open or fully closed ?
I still think it's an ugly looking aeroplane ...
Coff.
Quote from the RAF News Feed ... Just published ...
The UK's new, and only, stealth aircraft, the F35 Lightning, completed the first ever vertical take-off and landing.
What is the transition speed tolerance (from Engineborne vertical to Wingborne horizontal flight) for that damn great intake flap before it becomes a huge speed retarding spoiler ... does the intake flap have selective open/close settings or is it either fully open or fully closed ?
I still think it's an ugly looking aeroplane ...
Coff.
Last edited by CoffmanStarter; 21st May 2013 at 11:49.
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LO I find interesting that there seems to be the capacity to ensure the USMC can declare IOC with TR1 Hardware and 2B software at +/- the same time that the USAF declares IOC with TR2 Hardware and 3I software. With both of these configurations giving very much the same capability.
It is unclear to me if this means that all the presently available F35A's are to be upgraded to TR2 hardware to then have 3I installed or only new build aircraft when TR2 Hardware is available will be part of the IOC. Could get interesting in the training pipeline with the different software versions, yes I do know the simulator arguments.
It does make 3I a far more important software version than as I perceive it it was initially intended to be....
It is unclear to me if this means that all the presently available F35A's are to be upgraded to TR2 hardware to then have 3I installed or only new build aircraft when TR2 Hardware is available will be part of the IOC. Could get interesting in the training pipeline with the different software versions, yes I do know the simulator arguments.
It does make 3I a far more important software version than as I perceive it it was initially intended to be....
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Coff,
Perhaps I can help.
Yes, it goes 'up and down'. It's been doing that for some while, this was another step in the clearance programme from basic to operational flight clearances.
The aircraft transitions from pure jet borne (zero knots airborne) to pure wing borne flight (a lot faster) through a 'transition envelope' that reduces jet thrust as wing lift increases. As it does that, the lift fan intake door 'schedules' from the fully open position you see in that clip (about 80 degrees) down to a lower setting (around 30 degrees), which is maintained until the aircraft is ready to come off jet thrust altogether and shut down the lift fan. The door operation is fully automatic, as are almost all of the aircraft systems involved in executing the transition.
The lift fan intake door design was a major challenge, as the 'bi-fold' system used on the X-35 had some major drawbacks that appeared in flight test. The door needs to be able to allow maximum airflow into the fan in a variety of conditions, from the hover (from all directions without generating unwanted intake vortices) to around 250 knots, getting the air to execute a quick 90 degree turn down into the lift fan, again without excessive intake distortion. The solution was a team effort, but special mention goes to some very talented Brits who came up with the solution.
Sorry you think it's ugly - for my own part, I just see a beautiful solution to a tough problem.
Best Regards as ever to those doing their best to deliver the goods
Engines
Perhaps I can help.
Yes, it goes 'up and down'. It's been doing that for some while, this was another step in the clearance programme from basic to operational flight clearances.
The aircraft transitions from pure jet borne (zero knots airborne) to pure wing borne flight (a lot faster) through a 'transition envelope' that reduces jet thrust as wing lift increases. As it does that, the lift fan intake door 'schedules' from the fully open position you see in that clip (about 80 degrees) down to a lower setting (around 30 degrees), which is maintained until the aircraft is ready to come off jet thrust altogether and shut down the lift fan. The door operation is fully automatic, as are almost all of the aircraft systems involved in executing the transition.
The lift fan intake door design was a major challenge, as the 'bi-fold' system used on the X-35 had some major drawbacks that appeared in flight test. The door needs to be able to allow maximum airflow into the fan in a variety of conditions, from the hover (from all directions without generating unwanted intake vortices) to around 250 knots, getting the air to execute a quick 90 degree turn down into the lift fan, again without excessive intake distortion. The solution was a team effort, but special mention goes to some very talented Brits who came up with the solution.
Sorry you think it's ugly - for my own part, I just see a beautiful solution to a tough problem.
Best Regards as ever to those doing their best to deliver the goods
Engines
Good explanation, Engines. Thanks. Can I just clarify that the lift fan intake door isn't actually scheduling the power output from the lift fan, it's the guide vanes that do that, isn't it? During transition to conventional flight, the door is gradually closing to present a smaller surface area to the increasing airflow.
Last edited by Courtney Mil; 21st May 2013 at 12:37.
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CM,
Yes, sorry if I wasn't clear, I was answering Coff's question abou the lift fan door operation, and excluded the thrust control aspect.
You're right. Lift fan thrust is controlled by operation of the lift fan inlet guide vanes. The lift fan exhaust vane box is also used to help control thrust (by varying nozzle exit area), as well as vectoring the lift fan thrust angle.
The door scheduling does two things. First, it reduces door drag, so reducing power requirements and also door loading (so less weight of structure required). Secondly, and just as importantly, it improves the lift fan intake 'capture efficiency' - at higher forward speeds, the air doesn't really want to turn 90 degrees and go down the fan - having the door at 30 degrees makes it do that. (That was one of the shortcomings with the X-35 'bi-fold' design - it didn't work as well at higher forward speeds).
Hope this helps
Engines
Yes, sorry if I wasn't clear, I was answering Coff's question abou the lift fan door operation, and excluded the thrust control aspect.
You're right. Lift fan thrust is controlled by operation of the lift fan inlet guide vanes. The lift fan exhaust vane box is also used to help control thrust (by varying nozzle exit area), as well as vectoring the lift fan thrust angle.
The door scheduling does two things. First, it reduces door drag, so reducing power requirements and also door loading (so less weight of structure required). Secondly, and just as importantly, it improves the lift fan intake 'capture efficiency' - at higher forward speeds, the air doesn't really want to turn 90 degrees and go down the fan - having the door at 30 degrees makes it do that. (That was one of the shortcomings with the X-35 'bi-fold' design - it didn't work as well at higher forward speeds).
Hope this helps
Engines
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Thanks Engines ... all very clear ...
My question was prompted from a wish to try and understand how quickly the F35 could zip off in conventional wingborne flight ... as the most vulnerable position for a VTOL pilot to be in is the hover/transition. The Harrier was able to do this quite quickly.
Glad to hear British "Brains" are at work
Best ...
Coff.
My question was prompted from a wish to try and understand how quickly the F35 could zip off in conventional wingborne flight ... as the most vulnerable position for a VTOL pilot to be in is the hover/transition. The Harrier was able to do this quite quickly.
Glad to hear British "Brains" are at work
Best ...
Coff.
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Coff,
The best answer I can give to your question (how fast can the F-35 get from jet borne to wing-borne flight) is 'actually quite quickly'. (Sorry, but I don't know the precise answer).
It's important to note that the aircraft will rarely go from a hover to forward flight in an operational sortie, except if it has to abort a hover landing. All operational sorties will use a STO, not a VTO.
In a STO, the actual transition is controlled by a single selection made by the pilot after leaving the ground, using a switch on the left hand control 'inceptor'. The vehicle control systems systems then take over and do all the clever scheduling/door closing/flight control stuff. That takes a fixed time, I think it's under 15 seconds. All that time, the aircraft is climbing away at a fair rate.
Vulnerability is an interesting issue - a STOVL aircraft's timelines from arriving in the overhead to landing, and from starting takeoff roll to up and away are really quite short, in most cases a bit shorter than a normally loaded conventional jet. Yes, it's going more slowly during the transitions, but it usually occupies less airspace to do it.
Best regards as ever
Engines
The best answer I can give to your question (how fast can the F-35 get from jet borne to wing-borne flight) is 'actually quite quickly'. (Sorry, but I don't know the precise answer).
It's important to note that the aircraft will rarely go from a hover to forward flight in an operational sortie, except if it has to abort a hover landing. All operational sorties will use a STO, not a VTO.
In a STO, the actual transition is controlled by a single selection made by the pilot after leaving the ground, using a switch on the left hand control 'inceptor'. The vehicle control systems systems then take over and do all the clever scheduling/door closing/flight control stuff. That takes a fixed time, I think it's under 15 seconds. All that time, the aircraft is climbing away at a fair rate.
Vulnerability is an interesting issue - a STOVL aircraft's timelines from arriving in the overhead to landing, and from starting takeoff roll to up and away are really quite short, in most cases a bit shorter than a normally loaded conventional jet. Yes, it's going more slowly during the transitions, but it usually occupies less airspace to do it.
Best regards as ever
Engines
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Uh you aren't trying to paint a terrorist operation to destroy aircraft on the ground via infiltration tactics as a strike against a particular type of aircraft are you? the Harriers destroyed in afghanistan could have just as easily been F-16s or A-10s. Many Apaches were destroyed in Iraq when caught in the open by insurgents, but I wouldn't hold that as a strike against the Apache:
http://defensetech.org/2012/03/15/in...h-64s-in-iraq/
is that the apaches fault or the shutter bugs? I'm not blaming the aircraft on that.
Quote:
Don't quite get the Bill Sweetman reference, btw. Aviation writer, some great books and years in Janes. Don't see the issue here.
Aviation week saw an issue:
"Aviation Week is committed to providing objective aerospace and defense journalism based on independent and balanced coverage. Following comments posted on his personal Facebook page, the editorial team has decided that Bill Sweetman will not be covering the F-35 program for a period of time. We will continue to hold our journalists to the highest standards of editorial integrity to best serve the aerospace and defense community."
I know its the old "he isn't biased when he's biased for me!" thing. but yes there is an issue there, whether you see it or not. Its more obvious than exploding concrete to me, and was for aviation week as well.
If we want to play the "his credentials are good enough that there isn't an issue" game I can post tons of LM pilot interviews by former military flyers with impressive history, including combat. No issue with that? Billie Flynn LM Test Pilot, some great experience, flown many aircraft types and years in the RCAF. Don't see the issue here. I could link to Loren Thompson if you would like as well. OR how about General Mosely, USAF Ret.?
Pentagon Should Investigate Fighter Options Beyond The F-35
Bill Sweetman has become so toxic, they left his name of the above piece. I wonder why they would do such a thing? please don't try and convince me Bill is above bias, because not even his own publication thinks so. whether he is right or wrong is up for debate, but unbiased? no that case is closed.
http://defensetech.org/2012/03/15/in...h-64s-in-iraq/
is that the apaches fault or the shutter bugs? I'm not blaming the aircraft on that.
Quote:
Don't quite get the Bill Sweetman reference, btw. Aviation writer, some great books and years in Janes. Don't see the issue here.
Aviation week saw an issue:
"Aviation Week is committed to providing objective aerospace and defense journalism based on independent and balanced coverage. Following comments posted on his personal Facebook page, the editorial team has decided that Bill Sweetman will not be covering the F-35 program for a period of time. We will continue to hold our journalists to the highest standards of editorial integrity to best serve the aerospace and defense community."
I know its the old "he isn't biased when he's biased for me!" thing. but yes there is an issue there, whether you see it or not. Its more obvious than exploding concrete to me, and was for aviation week as well.
If we want to play the "his credentials are good enough that there isn't an issue" game I can post tons of LM pilot interviews by former military flyers with impressive history, including combat. No issue with that? Billie Flynn LM Test Pilot, some great experience, flown many aircraft types and years in the RCAF. Don't see the issue here. I could link to Loren Thompson if you would like as well. OR how about General Mosely, USAF Ret.?
Pentagon Should Investigate Fighter Options Beyond The F-35
Bill Sweetman has become so toxic, they left his name of the above piece. I wonder why they would do such a thing? please don't try and convince me Bill is above bias, because not even his own publication thinks so. whether he is right or wrong is up for debate, but unbiased? no that case is closed.
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Thanks again Engines ... I appreciate your time taken to explain in response to my questions
Best regards ...
Coff.
Best regards ...
Coff.
Last edited by CoffmanStarter; 21st May 2013 at 16:22.
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re: terrorist attacks on the ground. This may be a concern if you are in the kind of operation where you're running out of a small civilian airfield with a short runway (justification for the F-35B), since such things tend to be adjacent to towns, not all of whose residents may be fans of the US Marine Corps.
MANPADS could ruin your whole day as you come in for a VL or creeping VL, slow and committed with a nice big IR signature. Likewise guided rockets or mortars - the bad guy pulls the trigger just as you start final descent to touchdown. How fast can you taxi?
MANPADS could ruin your whole day as you come in for a VL or creeping VL, slow and committed with a nice big IR signature. Likewise guided rockets or mortars - the bad guy pulls the trigger just as you start final descent to touchdown. How fast can you taxi?
what if the locals don't like the USAF and the A-10? Or the US Army and the Apache? How does any of this apply specifically to the F-35B? "justification for the F-35B" is also about operating from ships Including the UK's.
I liked your exploding concrete myth better. 1/10
Oh dear oh dear. While I personally ignore Sweetman and Palmer at this point because the bias is overwhelming and often very selective. I prefer some of the other Wired/AV Week/Aviationist commentators. I have to say the inability to fact check the date on an article from three odd years ago or even mention the age of it really doesn't strengthen your case very much, if at all.
Vulnerability is an interesting issue - a STOVL aircraft's timelines from arriving in the overhead to landing, and from starting takeoff roll to up and away are really quite short, in most cases a bit shorter than a normally loaded conventional jet. Yes, it's going more slowly during the transitions, but it usually occupies less airspace to do it.
Last edited by Killface; 21st May 2013 at 20:39.
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Stuffy I imagine quite a lot.
In the same way that a huge amount of subsystems and software has to work together to keep any military jet since oooh probably the F16 actually in the air and flying..
In the same way that a huge amount of subsystems and software has to work together to keep any military jet since oooh probably the F16 actually in the air and flying..
So and with no wish to incite whatsoever, how many systems and subsystems have to operate "correctly" to enable the F35b to land ?
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Further RAF PR just released ...
RAF F35
Let's see what the "Bearded One" says after he reads this bit ..
Coff.
The F-35B Lightning II will place the UK at the forefront of fighter technology, giving the Royal Air Force a true multi-role all weather, day and night capability, able to operate from well-established land bases, deployed locations or the Queen Elizabeth Class Aircraft Carriers.
Let's see what the "Bearded One" says after he reads this bit ..
The RAF is the lead service for the operation of Lightning II and, like the Harrier before, the Joint Lightning II Force will be manned by both RAF and RN personnel.
Last edited by CoffmanStarter; 21st May 2013 at 20:04.
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Originally Posted by Killface
And If your aunt had balls...
"justification for the F-35B" is also about operating from ships Including the UK's.
I liked your exploding concrete myth better. 1/10
"justification for the F-35B" is also about operating from ships Including the UK's.
I liked your exploding concrete myth better. 1/10
If you want to be angry, go somewhere else. If you want discussion, please stay and exchange views. WITHOUT attacking people because your view is not the same as theirs.
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^You are right, I am sorry^
I will just say that those arguments could apply to any number of systems but for some reason the F-35B is specifically called out.
I will just say that those arguments could apply to any number of systems but for some reason the F-35B is specifically called out.
Last edited by Killface; 21st May 2013 at 20:43.
