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33 thoughts on “F35 Flight Control Software or Cat Amongst the CVF Pigeons”
wf
Interesting indeed. The F35 is using direct force control, something available as a manual system on the F14 as Direct Lift Control, to speed glidepath corrections. Hopefully, also to be utilised to remove buffet in low level flight
mmoomin
It’s still a 140/150 odd knot controlled crash onto a deck or land then stop as opposed to stop then land.
It’s making a massively difficult job easier but I can’t really see that the USN will actually reduce the number of deck landings and the tempo of them that a USN pilot has to do to maintain currency. They will just be easier and more likely to suceed.
martin
@ mmoomin
Agreed, the USN will still have the same requirements for deck landings. Why save money when you can keep doing what you have always done.
I don’t think it alters our CVF F35 equation at all. We all new about this technology before and it was perhaps one of the reasons for the initial switch to F35C but £ 5 billion conversion cost’s sink any argument.
SomewhatInvolved
Fascinating to see every control surface being involved in the landing equation – this is a huge leap forwards from traditional control techniques in a combat aircraft.
I think it has a fair impact on the F35 argument, as many of the anti-C crowd were citing the aircraft’s predicted poor handling and landing characteristics, overly high landing speeds and the deck hook failure issue. On the strength of this video most of the former problems have been addressed, and once the deck hook is fixed, the result will be an aircraft that is just as viable as its legacy predecessors.
mmoomin
@SomewhatInvolved I really don’t see that it does. It’s easier to get the plane on the deck yes, so that reduces your accident rate and increases the safety of doing it but it’s still never going to be as easy to train or maintain as STOVL’s hover then land.
Anyway the major point ‘against’ (in the context of our limited budget and manpower capability) CATOBAR was about it’s higher training burden and increased ‘miles’ on the air frames that come with CATOBAR.
The plane may be easier to land at a micro level but you still have the same number of pilots and deck crew needing deck qualification and maintenance of their skills.
wf
@mmoomin: does anyone actually have the accident rates for say, the F18 and the AV8B to hand for carrier-borne ops? My memory says the F18 beats out the AV8B, but I could be wrong. It’s certainly no slam dunk
Even more to the point, we are going to be doing a lot of SRVL, a technique that no-one except the VAAC Harrier team have tried. We can hardly declare it better than CATOBAR until it’s been tried for a few years
JustBeef Trousers
“Even more to the point, we are going to be doing a lot of SRVL, a technique that no-one except the VAAC Harrier team have tried”
exactly, and i’d be amazed if this technology was not equally relevant to SRVL.
SomewhatInvolved
mmoomin, well if you still believe the £5BN conversion price tag then nothing will change your mind. I simply pointed out that the deck landing issue was a major factor in switching to the B variant, and that that issue has been cleared up. As for airframe life, the B doesn’t have the structurally enhanced airframe of the C and has standard landing gear – in fact the B’s airframe has been deliberately thinned to get around weight issues. How confident are you that SRVL landings are going to be no less punishing than arrested landings on the beefed up C undercarriage?
Mike
The issue is with the C there was huge costs and problems surrounding it, more than just the conversion and airframe itself; all of which havent been considered/prepared for until that ‘quick draw’ switch in 2010. Its all one big headache, I’d rather we began with the original B and then build up to C, the purse-strings have long since shut tight.
Why wasn’t this heartily debated when it all began? Why is it now when plans and build has proceeded and money is tight, that people suddenly think we can just ‘switch’ with little/no consequence to an already troubled programe?
We blame BAe for a lot of service procurement woes, but this one lands at the door of Gov and MoD; stop meddeling and changing ideas, and get on with the chuffing job.
dan the man
we was never ever going to get the f35c because rolls royce and bae were nether going to let it happen why? because there was going to be job loss’s if we had the c instead of b because industraial share can imagine the conversation dear minster we understand why you want the c but do you realise if you have the c that rolls would have to lose 500 to a 1000 people in derby at the same time as bombider were losing 1000 to 1500 jobs also we are closing broughton we mite after close another site do you really want that because we will tell all why so it’s the b then and guess what im glad because we are not usn we are the royal navy and it also means that the royal airforce will have to share
Swimming Trunks
Should have been just one variant from the start – I’d have gone with STOVL because everyone would have been able to use it; USN, USMC, USAF, RN, RAF. If not STOVL then CV variant.
mmoomin
Please tell me you don’t subscribe to the imho eroneous view that BAE wanted to do themselves out of 5Billion quid worth of contract changes and amendments. BAE make the back of the plane and contribute other bits so they’d be making just as much cash B or C. Rolls Royce might not have been too happy though.
I’ve worked on some fairly large scale projects and just stopping one when it’s in full flow to make a ‘small’ change costs a lot of money. Something like a switch from STOVL to CATOBAR once production has started will cost a hell of a lot of money. I’d also expect a healthy amount of risk to be built into the cost because you have to ‘saw apart’ a half built aircraft carrier while modifying it’s design to fit an untried/untested (in a naval environment) electromagnetic catapult into an Aircraft carrier it wasn’t designed for. Put it another way Labour delayed production by a year when line items and major components had already been bought and work was getting underway. Additional cost to the program 1.5 billion. I can well believe 5 Billion for both carriers given that both are in various stages of construction right now. One of them already is the heaviest warship in our inventory and its only half a ship right now.
There is absolutely no point whatsoever in having one CATOBAR carrier, it has to be at least two to give year round capability.
I also don’t understand this insistence that we will always land SRVL? The plane has a KPP of being able to land vertically with two 1000lb bombs two anti air missiles and couple of 1000lbs of fuel on board in a ‘hot place’ East of Suez. From memory I think its between 3500 and 4000lbs in bring back to land vertically.
mmoomin
In fact this is what you’d be changing in build as it were (imagine doing it when built!!)
Out of interest why does it make a difference to BAE? Surely they build the same amount of F-35B as they do of the F-35C.
wf
@mmoomin: effectively, we will be using SRVL during nearly all operational sorties. 2 AAM’s, 2 bombs describes a very small loadout which I cannot imagine being used except for F117 type sorties. As the aircraft weight increases during lifetime, the need will increase
wf
@Tubby: RR build the majority of the lift fan. That being said, compared to their civil business, it’s a rounding error
Mark
Utter nonsense wf. The 2 1000 pounders is equivalent to 4 paveway 4 or possible 2 paveway 4 and 6 brimstone missiles care to compare that to current a/c load outs in afghan or Libya. The vlbb is not a start of life requirement.
dan the man
if im not mistaken bae will build the majority of the production airframe for our aircraft but only the back section on the rest so would lose out if we had changed to the c
mmoomin
Ssssshhh Tubby don’t use logic on this one.
As far as I’m aware BAE make the back of the aircraft and its no different for whatever version.
John Hartley
I understand the major hook mod on the C was just to make the hook more pointy so it slipped under the wires easier. Isn’t hi tech great?
Red Trousers
Seems it is all very focussed on the pilot doing a good job, and some systems in the plane “helping him”. Why is the ship not part of the equation, as well?
An ex-colleague of mine was a Rear Admiral USN who had thousands of carrier landings under his belt (he first flew sorties from carriers during Vietnam, so his experience went back decades). He proposed a system of lasers firing up and back from the carrier that could be sensed by the incoming plane, and then through maths and software inject into the HUD a glide slope for the pilot to follow. He declared that would be far easier than the pilot lining up lights by eyesight. Nowadays, that could be taken even further and injected into the plane’s little brain for the fly by wire or autopilot to assist. Whether his proposals were taken up or not I don’t know – they seem reasonable enough, and also presumably retrofittable to existing aircraft types.
The other thing that worries me is the whole concept of “every control surface being involved”. What happens if your flaps are shot to shit?
mmoomin
I read somewhere that the theoretical issue is that it’s not long enough to damp the ‘movement’ of the hook. The hook point apparently is a lot further back (this is from memory though) and shorter than previous designs due to the stealth characteristics of the aircraft (seems a little odd to me but there you are) and therefore making the hook longer would result in a lot of changes to the airframe as the stress loadings on the airframe will all have to change. Hence the effort to make the hooks claw grabbier. I think theres going to be some squeaky bums when they test that.
wf
@RT, the beauty of control configured aircraft is that they can compensate for said surfaces being missing automatically, rather than relying on an exceptional pilot.
The USN uses a laser based glidescope system, but it’s for the pilots.
wf
@mark: no room to carry more than 2 1000lb bombs and 2 AMRAAM internally in the F35B. 500lb Paveway are much the same size as 1000lb. Hence not nonsense. VLBB very relevant day one, since otherwise our carrier can only launch, or recover aircraft rather than both together.
Mark
Wf
So nearly all operational sorties now becomes day 1 operations. Which is a storm shadow mission in which case srvl would only be required for a not released or hang up which would be rare. So yes your statement was very much nonsense.
I know that, the 1000bs bomb will be replaced by paveway 4 and I guess ultimately spear3 if internal only is the only option. The point im making is operation load out today on most sustaining mission is vlbb capable on f35b.
mmoomin
@wf the margins on weight etc being used are the end of life margins not the initial ones. Anyone would think that Lockheed Martin has made military jets before. I think this whole VLBB thing has been conflated by those well known aircraft designers Sharkey Ward and Lewis Pages fag packet engineering estimates. I mean Sharkey had the final production planes costing what £190 Million each the LRIP ones we just got were £100 Million a throw so I’m not sure how much credance I can give them.
John
Regarding costs, the guys over on PPRUNE reckon someone is being economical with the truth regarding the conversion costs. The fixed costs of EMALS and AAR are approx £500B, so where the extra money comes into it. Before anyone jumps on the it’s all BAE’s fault bandwagon the PPRUNE guys dislike BAE as much as anyone and even they don’t them for the costs.
Aussie Johnno
Carrier approaches are all very well but the F-35C has still to demonstrate that it can take a wire. The whole issue has been very silent since the matter came up.
It was not like the fix was supposed to be very complicated (different profile for the hook tip and beefing up the hold down damper).
But it still appears to be a work in progress.
The basic problem is that the F-35C has a lineal 7.1 feet between the main wheels and and the hook tip extended. For comparision the F18 (all versions) has over 18 ft, the F-14 had 22 ft, the T-45 has 14.6 feet.
The problem isn’t rocket science (the main wheels hit the wire and start it dancing and the hook passes over it before it stablises) …and the fix is still awaited!
EMC2
“. From memory I think its between 3500 and 4000lbs in bring back to land vertically.”
“…the main wheels hit the wire and start it dancing…”
Is this really the only problem?
Seems like a giant ‘<' will fix it. Either the hook extends in two pieces (each being damped independently) or it rotates on the way down (being damped only on the hinge with the fuselage).
Alternatively the wire could be supported by fold-down sticks to increase the resonant frequency and decrease the amplitude of the oscillation?
Aussie Johnno
Yes Simon, most of the F-35C problem is the limited distance between the main wheels and the hook combined with a pretty high landing speed.
The whole hook assembly is also pretty short as it has to retract internally. The fix that was mooted was a revised hold down damper to keep the hook at the best angle and a more open mouthed hook. It remains to be seen it it works.
the obvious plan B is a longer semi exposed hook at some cost to stealth.
On the matter of arrestor wires, they are already held proud of the deck by steel rod strong backs welded length wise but the wires still move about.
Simon
Just actually watched the vid.
So, have they only just cottoned on to flaperons? I’d have thought every single jet fighter in the world used them!
V. interesting that things that have been on RC aircraft (like the RC bit for UAVs and the computer/giro controlled fly-by-wire) are only just getting onto real combat aircraft…
…unless I’ve missed something?
Lord Jim
Well according to announcements today, the RAF/RN will be getting around 48 ‘B’ variants for the CVF and a number of ‘A’ variants to replace the Tornado but numbers of the latter have not been made public.
Interesting indeed. The F35 is using direct force control, something available as a manual system on the F14 as Direct Lift Control, to speed glidepath corrections. Hopefully, also to be utilised to remove buffet in low level flight
It’s still a 140/150 odd knot controlled crash onto a deck or land then stop as opposed to stop then land.
It’s making a massively difficult job easier but I can’t really see that the USN will actually reduce the number of deck landings and the tempo of them that a USN pilot has to do to maintain currency. They will just be easier and more likely to suceed.
@ mmoomin
Agreed, the USN will still have the same requirements for deck landings. Why save money when you can keep doing what you have always done.
I don’t think it alters our CVF F35 equation at all. We all new about this technology before and it was perhaps one of the reasons for the initial switch to F35C but £ 5 billion conversion cost’s sink any argument.
Fascinating to see every control surface being involved in the landing equation – this is a huge leap forwards from traditional control techniques in a combat aircraft.
I think it has a fair impact on the F35 argument, as many of the anti-C crowd were citing the aircraft’s predicted poor handling and landing characteristics, overly high landing speeds and the deck hook failure issue. On the strength of this video most of the former problems have been addressed, and once the deck hook is fixed, the result will be an aircraft that is just as viable as its legacy predecessors.
@SomewhatInvolved I really don’t see that it does. It’s easier to get the plane on the deck yes, so that reduces your accident rate and increases the safety of doing it but it’s still never going to be as easy to train or maintain as STOVL’s hover then land.
Anyway the major point ‘against’ (in the context of our limited budget and manpower capability) CATOBAR was about it’s higher training burden and increased ‘miles’ on the air frames that come with CATOBAR.
The plane may be easier to land at a micro level but you still have the same number of pilots and deck crew needing deck qualification and maintenance of their skills.
@mmoomin: does anyone actually have the accident rates for say, the F18 and the AV8B to hand for carrier-borne ops? My memory says the F18 beats out the AV8B, but I could be wrong. It’s certainly no slam dunk
Even more to the point, we are going to be doing a lot of SRVL, a technique that no-one except the VAAC Harrier team have tried. We can hardly declare it better than CATOBAR until it’s been tried for a few years
“Even more to the point, we are going to be doing a lot of SRVL, a technique that no-one except the VAAC Harrier team have tried”
exactly, and i’d be amazed if this technology was not equally relevant to SRVL.
mmoomin, well if you still believe the £5BN conversion price tag then nothing will change your mind. I simply pointed out that the deck landing issue was a major factor in switching to the B variant, and that that issue has been cleared up. As for airframe life, the B doesn’t have the structurally enhanced airframe of the C and has standard landing gear – in fact the B’s airframe has been deliberately thinned to get around weight issues. How confident are you that SRVL landings are going to be no less punishing than arrested landings on the beefed up C undercarriage?
The issue is with the C there was huge costs and problems surrounding it, more than just the conversion and airframe itself; all of which havent been considered/prepared for until that ‘quick draw’ switch in 2010. Its all one big headache, I’d rather we began with the original B and then build up to C, the purse-strings have long since shut tight.
Why wasn’t this heartily debated when it all began? Why is it now when plans and build has proceeded and money is tight, that people suddenly think we can just ‘switch’ with little/no consequence to an already troubled programe?
We blame BAe for a lot of service procurement woes, but this one lands at the door of Gov and MoD; stop meddeling and changing ideas, and get on with the chuffing job.
we was never ever going to get the f35c because rolls royce and bae were nether going to let it happen why? because there was going to be job loss’s if we had the c instead of b because industraial share can imagine the conversation dear minster we understand why you want the c but do you realise if you have the c that rolls would have to lose 500 to a 1000 people in derby at the same time as bombider were losing 1000 to 1500 jobs also we are closing broughton we mite after close another site do you really want that because we will tell all why so it’s the b then and guess what im glad because we are not usn we are the royal navy and it also means that the royal airforce will have to share
Should have been just one variant from the start – I’d have gone with STOVL because everyone would have been able to use it; USN, USMC, USAF, RN, RAF. If not STOVL then CV variant.
Please tell me you don’t subscribe to the imho eroneous view that BAE wanted to do themselves out of 5Billion quid worth of contract changes and amendments. BAE make the back of the plane and contribute other bits so they’d be making just as much cash B or C. Rolls Royce might not have been too happy though.
I’ve worked on some fairly large scale projects and just stopping one when it’s in full flow to make a ‘small’ change costs a lot of money. Something like a switch from STOVL to CATOBAR once production has started will cost a hell of a lot of money. I’d also expect a healthy amount of risk to be built into the cost because you have to ‘saw apart’ a half built aircraft carrier while modifying it’s design to fit an untried/untested (in a naval environment) electromagnetic catapult into an Aircraft carrier it wasn’t designed for. Put it another way Labour delayed production by a year when line items and major components had already been bought and work was getting underway. Additional cost to the program 1.5 billion. I can well believe 5 Billion for both carriers given that both are in various stages of construction right now. One of them already is the heaviest warship in our inventory and its only half a ship right now.
There is absolutely no point whatsoever in having one CATOBAR carrier, it has to be at least two to give year round capability.
Anyway I digress.
CATOBAR landing speed 150ish knots
SRVL landing speed circa 35 knots
I also don’t understand this insistence that we will always land SRVL? The plane has a KPP of being able to land vertically with two 1000lb bombs two anti air missiles and couple of 1000lbs of fuel on board in a ‘hot place’ East of Suez. From memory I think its between 3500 and 4000lbs in bring back to land vertically.
In fact this is what you’d be changing in build as it were (imagine doing it when built!!)
http://www.flickr.com/photos/qeclasscarriers/7494913708/in/photostream
http://www.flickr.com/photos/qeclasscarriers/7513637722/in/photostream
http://www.flickr.com/photos/qeclasscarriers/7583371106/in/photostream
Out of interest why does it make a difference to BAE? Surely they build the same amount of F-35B as they do of the F-35C.
@mmoomin: effectively, we will be using SRVL during nearly all operational sorties. 2 AAM’s, 2 bombs describes a very small loadout which I cannot imagine being used except for F117 type sorties. As the aircraft weight increases during lifetime, the need will increase
@Tubby: RR build the majority of the lift fan. That being said, compared to their civil business, it’s a rounding error
Utter nonsense wf. The 2 1000 pounders is equivalent to 4 paveway 4 or possible 2 paveway 4 and 6 brimstone missiles care to compare that to current a/c load outs in afghan or Libya. The vlbb is not a start of life requirement.
if im not mistaken bae will build the majority of the production airframe for our aircraft but only the back section on the rest so would lose out if we had changed to the c
Ssssshhh Tubby don’t use logic on this one.
As far as I’m aware BAE make the back of the aircraft and its no different for whatever version.
I understand the major hook mod on the C was just to make the hook more pointy so it slipped under the wires easier. Isn’t hi tech great?
Seems it is all very focussed on the pilot doing a good job, and some systems in the plane “helping him”. Why is the ship not part of the equation, as well?
An ex-colleague of mine was a Rear Admiral USN who had thousands of carrier landings under his belt (he first flew sorties from carriers during Vietnam, so his experience went back decades). He proposed a system of lasers firing up and back from the carrier that could be sensed by the incoming plane, and then through maths and software inject into the HUD a glide slope for the pilot to follow. He declared that would be far easier than the pilot lining up lights by eyesight. Nowadays, that could be taken even further and injected into the plane’s little brain for the fly by wire or autopilot to assist. Whether his proposals were taken up or not I don’t know – they seem reasonable enough, and also presumably retrofittable to existing aircraft types.
The other thing that worries me is the whole concept of “every control surface being involved”. What happens if your flaps are shot to shit?
I read somewhere that the theoretical issue is that it’s not long enough to damp the ‘movement’ of the hook. The hook point apparently is a lot further back (this is from memory though) and shorter than previous designs due to the stealth characteristics of the aircraft (seems a little odd to me but there you are) and therefore making the hook longer would result in a lot of changes to the airframe as the stress loadings on the airframe will all have to change. Hence the effort to make the hooks claw grabbier. I think theres going to be some squeaky bums when they test that.
@RT, the beauty of control configured aircraft is that they can compensate for said surfaces being missing automatically, rather than relying on an exceptional pilot.
The USN uses a laser based glidescope system, but it’s for the pilots.
@mark: no room to carry more than 2 1000lb bombs and 2 AMRAAM internally in the F35B. 500lb Paveway are much the same size as 1000lb. Hence not nonsense. VLBB very relevant day one, since otherwise our carrier can only launch, or recover aircraft rather than both together.
Wf
So nearly all operational sorties now becomes day 1 operations. Which is a storm shadow mission in which case srvl would only be required for a not released or hang up which would be rare. So yes your statement was very much nonsense.
I know that, the 1000bs bomb will be replaced by paveway 4 and I guess ultimately spear3 if internal only is the only option. The point im making is operation load out today on most sustaining mission is vlbb capable on f35b.
@wf the margins on weight etc being used are the end of life margins not the initial ones. Anyone would think that Lockheed Martin has made military jets before. I think this whole VLBB thing has been conflated by those well known aircraft designers Sharkey Ward and Lewis Pages fag packet engineering estimates. I mean Sharkey had the final production planes costing what £190 Million each the LRIP ones we just got were £100 Million a throw so I’m not sure how much credance I can give them.
Regarding costs, the guys over on PPRUNE reckon someone is being economical with the truth regarding the conversion costs. The fixed costs of EMALS and AAR are approx £500B, so where the extra money comes into it. Before anyone jumps on the it’s all BAE’s fault bandwagon the PPRUNE guys dislike BAE as much as anyone and even they don’t them for the costs.
Carrier approaches are all very well but the F-35C has still to demonstrate that it can take a wire. The whole issue has been very silent since the matter came up.
It was not like the fix was supposed to be very complicated (different profile for the hook tip and beefing up the hold down damper).
But it still appears to be a work in progress.
The basic problem is that the F-35C has a lineal 7.1 feet between the main wheels and and the hook tip extended. For comparision the F18 (all versions) has over 18 ft, the F-14 had 22 ft, the T-45 has 14.6 feet.
The problem isn’t rocket science (the main wheels hit the wire and start it dancing and the hook passes over it before it stablises) …and the fix is still awaited!
“. From memory I think its between 3500 and 4000lbs in bring back to land vertically.”
KKP for Vertical Landing Bring Back (VLBB) is 4710lb
page 4
http://www.f-16.net/f-16_forum_download-id-11277.html
http://www.fas.org/sgp/crs/weapons/RL30563.pdf
“…the main wheels hit the wire and start it dancing…”
Is this really the only problem?
Seems like a giant ‘<' will fix it. Either the hook extends in two pieces (each being damped independently) or it rotates on the way down (being damped only on the hinge with the fuselage).
Alternatively the wire could be supported by fold-down sticks to increase the resonant frequency and decrease the amplitude of the oscillation?
Yes Simon, most of the F-35C problem is the limited distance between the main wheels and the hook combined with a pretty high landing speed.
The whole hook assembly is also pretty short as it has to retract internally. The fix that was mooted was a revised hold down damper to keep the hook at the best angle and a more open mouthed hook. It remains to be seen it it works.
the obvious plan B is a longer semi exposed hook at some cost to stealth.
On the matter of arrestor wires, they are already held proud of the deck by steel rod strong backs welded length wise but the wires still move about.
Just actually watched the vid.
So, have they only just cottoned on to flaperons? I’d have thought every single jet fighter in the world used them!
V. interesting that things that have been on RC aircraft (like the RC bit for UAVs and the computer/giro controlled fly-by-wire) are only just getting onto real combat aircraft…
…unless I’ve missed something?
Well according to announcements today, the RAF/RN will be getting around 48 ‘B’ variants for the CVF and a number of ‘A’ variants to replace the Tornado but numbers of the latter have not been made public.