F-35 Cancelled, then what ?
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But where does it "bolt" too?
As has been intimated earlier, the thorny question of µ has never actually been fully addressed.
It will be VERY illuminating to see how the RN will actually manage deck operations incl rvl etc, from the aspect of µ and F35 flying ops in ALL conditions..
It will be VERY illuminating to see how the RN will actually manage deck operations incl rvl etc, from the aspect of µ and F35 flying ops in ALL conditions..
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Glad, Courtney and others,
Please be as sceptical as you wish - open forum and all that. I don't 'always' cover things - if I don't know, i say so. Or try to.Sorry if I'm not clear enough sometimes.
Deck coefficient of friction is well understood and the expected values are known. The USN have always had much better deck coatings than the UK, at higher cost. The question of mu has been addressed - in that the team know what it should be if the coatings go on as per spec. And they know what the F-35B landing gear will produce. It's been tested - like most everything else.
A small point of clarification - I was on the deck of Invincible when the Sea Harrier went over the side. Wasn't all about mu. Here are the facts - be as sceptical as you want.
The aircraft was on the runway about to launch against a suspected incoming threat. (So no lashings fitted). Fully loaded. The ship had to manoeuvre quickly to get on to the flying course, and went hard starboard in a biggish sea. We started heeling over to port. Quickly. The angle of heel was somewhere around 10 to 15 degrees - possibly a bit more. Lots. Enough to get everyone on deck grabbing for something to hold on. High wind also from starboard, coming round on to the bow.
It was at this point that the FAA learned something about the Harrier nose leg not covered in any of the manuals. It had a break out design so that excessive side forces weren't fed into the airframe. So, even though it was centred for launch, as the side loads came on it suddenly (and I mean suddenly) castored, allowing the aircraft to (very quickly) rotate around the main wheel assembly to port. Deck was still heeling over to port.
This was the point at which mu came into play. The flight deck was, by this time, fairly dirty and slick. (We had no effective deck scrubbing kit at that time). So, as the aircraft nose wheel went over the side of the deck, there was very little to stop the aircraft sliding to port and simply jumping over the side, clearing the catwalk as it went. Pilot ejected at around 45 degrees nose down, recovered by a Sea King that was standing off waiting to recover. (Good work in hefty seas by the way).
Lessons learned very quickly:
1. Get the deck scrubbed and keep scrubbing. An old FAA routine that we had forgotten through not doing carrier aviation for a few years. Deck scrubbing machines were procured immediately and are still in constant use.
2. Restrict ship manoeuvring when aircraft not tied down on deck. See above.
3. Stuff happens in war.
It should (but probably won't) go without saying that the F-35B's landing gear is massively better for deck work than the Sea Harrier's somewhat 'hokey' 1950s style bicycle layout. Brakes that work, and a stable tricycle layout. Moreover, QEC will not move around at anything like the amount the CVs did.
But are there risks in SSLs? Sure there are. The team are working those with all the techniques at their disposal. Deck trials will be the final proof. But they won't even take place unless the teams have wrung out all the data as far as they can first. The fact that they are still going forward with SSLs should tell us that they haven't found a 'stopper' yet.
I hope this stuff helps a little. I'll now desist further posts on this subject, as I think I'm at the point when I'll start repeating myself. And few will listen - I don't blame them.
Best Regards as ever to those who have actually worked on seagoing STOVL and have the knowledge
Engines
Please be as sceptical as you wish - open forum and all that. I don't 'always' cover things - if I don't know, i say so. Or try to.Sorry if I'm not clear enough sometimes.
Deck coefficient of friction is well understood and the expected values are known. The USN have always had much better deck coatings than the UK, at higher cost. The question of mu has been addressed - in that the team know what it should be if the coatings go on as per spec. And they know what the F-35B landing gear will produce. It's been tested - like most everything else.
A small point of clarification - I was on the deck of Invincible when the Sea Harrier went over the side. Wasn't all about mu. Here are the facts - be as sceptical as you want.
The aircraft was on the runway about to launch against a suspected incoming threat. (So no lashings fitted). Fully loaded. The ship had to manoeuvre quickly to get on to the flying course, and went hard starboard in a biggish sea. We started heeling over to port. Quickly. The angle of heel was somewhere around 10 to 15 degrees - possibly a bit more. Lots. Enough to get everyone on deck grabbing for something to hold on. High wind also from starboard, coming round on to the bow.
It was at this point that the FAA learned something about the Harrier nose leg not covered in any of the manuals. It had a break out design so that excessive side forces weren't fed into the airframe. So, even though it was centred for launch, as the side loads came on it suddenly (and I mean suddenly) castored, allowing the aircraft to (very quickly) rotate around the main wheel assembly to port. Deck was still heeling over to port.
This was the point at which mu came into play. The flight deck was, by this time, fairly dirty and slick. (We had no effective deck scrubbing kit at that time). So, as the aircraft nose wheel went over the side of the deck, there was very little to stop the aircraft sliding to port and simply jumping over the side, clearing the catwalk as it went. Pilot ejected at around 45 degrees nose down, recovered by a Sea King that was standing off waiting to recover. (Good work in hefty seas by the way).
Lessons learned very quickly:
1. Get the deck scrubbed and keep scrubbing. An old FAA routine that we had forgotten through not doing carrier aviation for a few years. Deck scrubbing machines were procured immediately and are still in constant use.
2. Restrict ship manoeuvring when aircraft not tied down on deck. See above.
3. Stuff happens in war.
It should (but probably won't) go without saying that the F-35B's landing gear is massively better for deck work than the Sea Harrier's somewhat 'hokey' 1950s style bicycle layout. Brakes that work, and a stable tricycle layout. Moreover, QEC will not move around at anything like the amount the CVs did.
But are there risks in SSLs? Sure there are. The team are working those with all the techniques at their disposal. Deck trials will be the final proof. But they won't even take place unless the teams have wrung out all the data as far as they can first. The fact that they are still going forward with SSLs should tell us that they haven't found a 'stopper' yet.
I hope this stuff helps a little. I'll now desist further posts on this subject, as I think I'm at the point when I'll start repeating myself. And few will listen - I don't blame them.
Best Regards as ever to those who have actually worked on seagoing STOVL and have the knowledge
Engines
Ecce Homo! Loquitur...
Interesting article, data translated from a an analysis piece posted on Sina's military news web portal.
Japan can't outgun China's J-20 with F-35A purchase
Japan can't outgun China's J-20 with F-35A purchase
Engines,
Good commentary on both topics there, thank you.
Your first paragraph confuses me slightly; I am not sceptical about this, merely interested in a part of the programme that is going to be important the UK operating the F-35 and that has not been widely publicised. It looks to me like glad rag, judging by his question, feels the same.
Neither was my illustration of the importance of maintaining mu an attempt to be sceptical. Talking to others, who were also involved, in the South Atlantiic after the event, their feeling was much as you described; the condition of the deck was a player in the loss of ZA174.
I cannot see where there was a remark about you "always" covering things. When you do, it is very much appreciated. Again, it looks like you may mistake the opinions and questions from those of us that are not as well-informed about the programme as being sceptical. I don't think that is the case.
But thank you again anyway.
Good commentary on both topics there, thank you.
Your first paragraph confuses me slightly; I am not sceptical about this, merely interested in a part of the programme that is going to be important the UK operating the F-35 and that has not been widely publicised. It looks to me like glad rag, judging by his question, feels the same.
Neither was my illustration of the importance of maintaining mu an attempt to be sceptical. Talking to others, who were also involved, in the South Atlantiic after the event, their feeling was much as you described; the condition of the deck was a player in the loss of ZA174.
I cannot see where there was a remark about you "always" covering things. When you do, it is very much appreciated. Again, it looks like you may mistake the opinions and questions from those of us that are not as well-informed about the programme as being sceptical. I don't think that is the case.
But thank you again anyway.
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Is that radar absorbing sand?
Do a Hover - it avoids G
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B STOVL flight control software - background
The B’s flight control software which provides the handling characteristics that the pilot sees during the STOVL speed range (regardless of the airframe aerodynamics or lift system forces present at any time) is a very well developed and tested aspect of the overall programme.
If I can convince some posters of that it may help them have confidence in the handling queries that crop up here from time to time and stop some people feeling that if they can’t see a video of a particular manoeuvre on YouTube then there has to be a future problem being covered up by L-M or others.
My personal position is that I know nothing about programme costs, politics, support issues and timescales and all those other things that may be right or wrong with the programme. However I do know a bit about the flight control software because I went to the first meeting about it in 1971 (yes 1971) and was associated with its development from then until I last flew it in the VAAC Harrier in 1999.
In 1971 the RAE scientists at Farnborough were looking to improve on what the pilot experienced in the Harrier, which at that time had then been in service for two years. The elephant in the room was asking the pilot to control both thrust amount and thrust direction with his left hand. They wanted (correctly) to get rid of the nozzle lever to avoid the pilot boob of moving the wrong lever. It was after all only a matter of time before any of us did that (one day I stop-cocked the engine instead of selecting the reverse thrust angle but was lucky enough to have a few knots on at the time and the dying whine woke me up).
As befitted a research establishment the RAE were not looking to mod the Harrier fleet but to start with a clean sheet of paper about what the pilot should be given in any Harrier replacement which turned out to be the F35B. I won’t bore you with the very large number of “what does the left hand do and what does the right hand do” ideas during a whole raft of possible STOVL manoeuvres, however we flew most of these options in the VAAC Harrier from the completely digital rear cockpit, the front cockpit having normal Harrier controls for the safety pilot.
In the end the preferred option (for all except Harrier pilots) turned out to be “the left hand controls speed and the right hand controls height”. The team found even non pilots could use this system without training. Result. Harrier pilots had of course learned to use the nozzle lever which (they thought) made them better that non nozzle aviators and turkeys don’t vote for Christmas.
The capability of the VAAC aircraft as a design tool had to be experienced to be believed. It was possible to sit in the hover on this single channel 100% authority flight control system and wobble the stick to see what you thought of (say) the roll control sensitivity, feel you would like a higher value, then select that parameter on a panel in the cockpit and while the system was engaged and flying the aircraft (!) dial up the higher value and have another wobble on the stick. Do optimisation systems come any better?
(Before anybody gasps at the apparent risks of such a system let me assure you that the boffins knew what they were doing and had installed an independent monitor to keep the aircraft safe regardless - but that is a whole other story and not relevant to this thread).
By 1999 a lot of JSF project office personnel and others had flown the optimised system and it is a matter of history that this RAE (later DERA and later still QinetiQ) STOVL flight control system was taken up by the JSF team for the B.
So please relax. There may well be issues over the whole JSF programme but the B’s STOVL flight control system is not one of them and don’t forget that in decelerating to the hover every intermediate speed is experienced!
The B’s flight control software which provides the handling characteristics that the pilot sees during the STOVL speed range (regardless of the airframe aerodynamics or lift system forces present at any time) is a very well developed and tested aspect of the overall programme.
If I can convince some posters of that it may help them have confidence in the handling queries that crop up here from time to time and stop some people feeling that if they can’t see a video of a particular manoeuvre on YouTube then there has to be a future problem being covered up by L-M or others.
My personal position is that I know nothing about programme costs, politics, support issues and timescales and all those other things that may be right or wrong with the programme. However I do know a bit about the flight control software because I went to the first meeting about it in 1971 (yes 1971) and was associated with its development from then until I last flew it in the VAAC Harrier in 1999.
In 1971 the RAE scientists at Farnborough were looking to improve on what the pilot experienced in the Harrier, which at that time had then been in service for two years. The elephant in the room was asking the pilot to control both thrust amount and thrust direction with his left hand. They wanted (correctly) to get rid of the nozzle lever to avoid the pilot boob of moving the wrong lever. It was after all only a matter of time before any of us did that (one day I stop-cocked the engine instead of selecting the reverse thrust angle but was lucky enough to have a few knots on at the time and the dying whine woke me up).
As befitted a research establishment the RAE were not looking to mod the Harrier fleet but to start with a clean sheet of paper about what the pilot should be given in any Harrier replacement which turned out to be the F35B. I won’t bore you with the very large number of “what does the left hand do and what does the right hand do” ideas during a whole raft of possible STOVL manoeuvres, however we flew most of these options in the VAAC Harrier from the completely digital rear cockpit, the front cockpit having normal Harrier controls for the safety pilot.
In the end the preferred option (for all except Harrier pilots) turned out to be “the left hand controls speed and the right hand controls height”. The team found even non pilots could use this system without training. Result. Harrier pilots had of course learned to use the nozzle lever which (they thought) made them better that non nozzle aviators and turkeys don’t vote for Christmas.
The capability of the VAAC aircraft as a design tool had to be experienced to be believed. It was possible to sit in the hover on this single channel 100% authority flight control system and wobble the stick to see what you thought of (say) the roll control sensitivity, feel you would like a higher value, then select that parameter on a panel in the cockpit and while the system was engaged and flying the aircraft (!) dial up the higher value and have another wobble on the stick. Do optimisation systems come any better?
(Before anybody gasps at the apparent risks of such a system let me assure you that the boffins knew what they were doing and had installed an independent monitor to keep the aircraft safe regardless - but that is a whole other story and not relevant to this thread).
By 1999 a lot of JSF project office personnel and others had flown the optimised system and it is a matter of history that this RAE (later DERA and later still QinetiQ) STOVL flight control system was taken up by the JSF team for the B.
So please relax. There may well be issues over the whole JSF programme but the B’s STOVL flight control system is not one of them and don’t forget that in decelerating to the hover every intermediate speed is experienced!
Last edited by John Farley; 4th Jun 2015 at 13:06. Reason: typo
JF -
I actually agree.
The STOVL element of JSF, in isolation, seems to work amazingly well, transforming what was very tricky on the Harrier to something quite stable, routine and easy for the pilot.
My main issue is whether the extra military options that it provides to a joint force is worth the cost in money, schedule or impact on the other variants.
I actually agree.
The STOVL element of JSF, in isolation, seems to work amazingly well, transforming what was very tricky on the Harrier to something quite stable, routine and easy for the pilot.
My main issue is whether the extra military options that it provides to a joint force is worth the cost in money, schedule or impact on the other variants.
LO -
I actually agree too. The politics and the history have led us to where we are, though, and the most important thing now is where it goes from here. We're way past the point of redesigning the carriers again to take anything else so we pretty much need to crack on and keep asking the questions about how THIS will work.
Nothing wrong with that.
I actually agree too. The politics and the history have led us to where we are, though, and the most important thing now is where it goes from here. We're way past the point of redesigning the carriers again to take anything else so we pretty much need to crack on and keep asking the questions about how THIS will work.
Nothing wrong with that.
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JF thank you for that very informative post above. It would be great if you could point us [me] towards any sources that detail the VAAC Harrier flying control integration.
thanks
gr.
https://books.google.co.uk/books?id=...rcraft&f=false
thanks
gr.
https://books.google.co.uk/books?id=...rcraft&f=false
Last edited by glad rag; 4th Jun 2015 at 20:57. Reason: for those who are interested..
As befitted a research establishment the RAE were not looking to mod the Harrier fleet but to start with a clean sheet of paper about what the pilot should be given in any Harrier replacement which turned out to be the F35B. I won’t bore you with the very large number of “what does the left hand do and what does the right hand do” ideas during a whole raft of possible STOVL manoeuvres, however we flew most of these options in the VAAC Harrier from the completely digital rear cockpit, the front cockpit having normal Harrier controls for the safety pilot.
Do a Hover - it avoids G
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t43562
Don't start trying to use common sense when it comes to research organisations and defence matters - especially with hindsight!
Seriously, with a clean sheet of paper approach to the controls research nobody knew how long it would all take.
Also changing a fleet of mechanical aeroplanes into FBW would just never have been a starter.
Don't start trying to use common sense when it comes to research organisations and defence matters - especially with hindsight!
Seriously, with a clean sheet of paper approach to the controls research nobody knew how long it would all take.
Also changing a fleet of mechanical aeroplanes into FBW would just never have been a starter.
There were plans along the way for a Harrier III, which could have been fly-by-wire (instead of fly-by-bicycle-chain?). However, at that point you'd probably have wanted to start over.
The much-maligned Boeing X-32 was more Harrier-like in terms of moving parts than the LM design (dubbed "Chitty Chitty Bang Bang" by a designer friend, very early in the game) but could just not generate the necessary performance needed for a stealth design.
The much-maligned Boeing X-32 was more Harrier-like in terms of moving parts than the LM design (dubbed "Chitty Chitty Bang Bang" by a designer friend, very early in the game) but could just not generate the necessary performance needed for a stealth design.
I suspect not too far from losing the aircraft, but hopefully the pilot would have whacked out first - would that have made it the most expensive abandonment in history.................
Ecce Homo! Loquitur...
I suspect not too far from losing the aircraft, but hopefully the pilot would have whacked out first - would that have made it the most expensive abandonment in history.................
