F-35 Cancelled, then what ?
Originally Posted by A1B
This is really nit picking of you in my view.
Do you now understand the sensitivity of simulation to data inaccuracies or do you still insist on believing and then stating results from trials conducted with certain assumed data, some of which has since been degraded?
The Air Force's standard air-to-air engagement analysis model, also
used by allied air forces to assess air-combat performance, pitted the 5th
generation F-35 against all advanced 4th generation fighters in a variety
of simulated scenarios.
used by allied air forces to assess air-combat performance, pitted the 5th
generation F-35 against all advanced 4th generation fighters in a variety
of simulated scenarios.
It is stuff like that that starts to make me doubt
Last edited by Courtney Mil; 18th Feb 2016 at 22:15.
If the press release is interpreted literally, the simulation would not have included the Su-35, which was not available on the market because the VVS had not ordered it.
Also, the wording in that section says nothing about "adversary" fighters, so maybe someone here can comment on how the JSF is 400 per cent better in A2A than Typhoon.
Finally, which companies have "jurno's" (a spelling error and a grocer's apostrophe in seven characters!) on their payroll? Come on, man, tell us! Speak truth to power! Are you a man or a mouse?
Also, the wording in that section says nothing about "adversary" fighters, so maybe someone here can comment on how the JSF is 400 per cent better in A2A than Typhoon.
Finally, which companies have "jurno's" (a spelling error and a grocer's apostrophe in seven characters!) on their payroll? Come on, man, tell us! Speak truth to power! Are you a man or a mouse?
Join Date: Jul 2015
Location: aus
Posts: 277
Likes: 0
Received 0 Likes
on
0 Posts
do you have a source to where they didn't use current data? I'm sure the test pilots did sustained turns early in the piece and would have that data well before that sim was done, in the time line of sim results released...publicly releasing the down grading of sustained turn etc is another matter. both the release and testimony was in 2012.
"Do you now understand the sensitivity of simulation to data inaccuracies or do you still insist on believing and then stating results from trials conducted with certain assumed data, some of which has since been degraded?"
The air force has the best sims and data going, either accept or reject, as you wish. looking from the outside and saying where they have it wrong? not so much. all the teens, typhoon is known.. and more than likely rafale and gripen would give enough to be run in sims for joint exercises. they have su-27 and one of the members of the 5 powers group has the su-30.
CM, you are ex f-15 and was involved in some of the typhoon stuff. you are the only one's attitude I don't understand here, when compared to what other f-15 and typhoon pilots say
"Do you now understand the sensitivity of simulation to data inaccuracies or do you still insist on believing and then stating results from trials conducted with certain assumed data, some of which has since been degraded?"
The air force has the best sims and data going, either accept or reject, as you wish. looking from the outside and saying where they have it wrong? not so much. all the teens, typhoon is known.. and more than likely rafale and gripen would give enough to be run in sims for joint exercises. they have su-27 and one of the members of the 5 powers group has the su-30.
CM, you are ex f-15 and was involved in some of the typhoon stuff. you are the only one's attitude I don't understand here, when compared to what other f-15 and typhoon pilots say
Last edited by a1bill; 18th Feb 2016 at 22:42.
Interesting that the 400/600 per cent brag doesn't show up in here:
https://www.f35.com/news/detail/join...is-boring-blog
Indeed, I don't recall seeing it in a while.
https://www.f35.com/news/detail/join...is-boring-blog
Indeed, I don't recall seeing it in a while.
Join Date: Dec 2010
Location: Middle America
Age: 84
Posts: 1,167
Likes: 0
Received 0 Likes
on
0 Posts
a1bill,
Simulations are always built on assumptions when actual data isn't available, they might be correct or wrong. So, what are the assumptions for this point you advertise? The F-35 has been on a slippery slope down the hill from what was originally promised. Where on the slope are the assumptions based? So far, the only real data point is the encounter with the F-16, leaked to the general public, that didn't go to well for the F-35. But you can revive the arguments of the fine points of why which were already discussed many pages ago. In the meantime, all of these F-35 performance claims tends to be window dressing by a combination of L-M, the US DoD and those who are attempting to justify their decisions to purchase the F-35 at an inflated prices, certainly by the time the F-35 is really ready for front line usage. Time races on, faster than the F-35.
"F-35 Lightning II is at least
400 percent more effective in air-to-air combat capability than the best
fighters currently available in the international market.
400 percent more effective in air-to-air combat capability than the best
fighters currently available in the international market.
Join Date: May 2000
Location: UK and where I'm sent!
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
A1Bill, it looks very much like you have been caught manipulating the text of a briefing to suit your own position. It also looks like you are equally selective about which questions you answer here and which ones you ignore. That doesn't make you very credible, I'm afraid.
There is lots of very good stuff about F-35, which doesn't get mentioned much here because you end up in ridiculous arguments about out of date, ill founded claims and deliberately misrepresenting other's statements instead of engaging in reasoned debate - debate includes listening to and taking on board what others say. You are currently doing more to discredit the F-35 with your approach than you do to promote it.
There is lots of very good stuff about F-35, which doesn't get mentioned much here because you end up in ridiculous arguments about out of date, ill founded claims and deliberately misrepresenting other's statements instead of engaging in reasoned debate - debate includes listening to and taking on board what others say. You are currently doing more to discredit the F-35 with your approach than you do to promote it.
Originally Posted by A1B
do you have a source to where they didn't use current data? I'm sure the test pilots did sustained turns early in the piece and would have that data well before that sim was done, in the time line of sim results released...publicly releasing the down grading of sustained turn etc is another matter. both the release and testimony was in 2012.
Installed engine thrust and fuel burn; airframe lift, drag, mass and obscuration; 3D, multiband RCS (including weapons bay door cycling for launch/release); radar probability of detection, tracking algorithms, eclipsing, co-channel interference; IRST detection, weather, signal degradation, target characteristics; datalink connectivity (basic model); missile seeker model, gimbal limits, radar scan volume coverage for support, target obscuration and manoeuvre (including target g), sun/glint, exhaust plume obscuration, boost/sustain dynamics, navigation law, MBC, aerodynamic performance, fusing.........
Each of those characteristics requires an huge number of data. The entire dataset for even a simple trial runs to over 200 pages of small print.
You may be able to work out which parts of that lot are affected by changes to sustained turn rate and which parts were not precisely known when the simulation was conducted.
What have Typhoon and F-15 pilots said to you that is so different to that?
Last edited by Courtney Mil; 19th Feb 2016 at 00:08.
As an aside and a little light relief, the most fun to be had in the BVR combat sims is in the pre-trial testing of the software/dataset/modelling. Instead of paying for an entire team of frontline pilots to fly the sims, the scientists and programmers that do the clever numbers fly the sims along with a few pilots. While the boffins had a very limited knowledge of combat tactics, radar and aircraft handling, etc, they could often be unbeatable if they go, say, 4v4 against the pilots. Their manoeuvre based on their knowledge of the modelling and missile performance data (kinematic and guidance) beats the pilots' realistic tactics.
Join Date: Oct 2006
Location: The Great Midwest
Posts: 245
Likes: 0
Received 0 Likes
on
0 Posts
Same here. While attending USAF test pilot school we took a trip to a new simulator. One of the instructors and I flew against each other (we actually had both been in the same squadron at RAF Lakenheath).
The set up was basically a fly out to 20 nm separation then turn in. First to get radar lock could shoot BVR. So the instructor kept his speed up to around 450 kts for the turn-in. I decided that the game was to complete the turn the quickest so I flew at 275 kts (not a very good speed for real combat). After I got missile kills on the first three engagements I finally revealed my “secret” tactic.
The set up was basically a fly out to 20 nm separation then turn in. First to get radar lock could shoot BVR. So the instructor kept his speed up to around 450 kts for the turn-in. I decided that the game was to complete the turn the quickest so I flew at 275 kts (not a very good speed for real combat). After I got missile kills on the first three engagements I finally revealed my “secret” tactic.
I saw one of the more recent documentaries about the F-35 flight test program, and when asked for a comment about the flight characteristics of the aircraft one of the pilots replied "well it goes where you point it".
Talk about damning with faint praise.
Talk about damning with faint praise.
Join Date: Jul 2015
Location: aus
Posts: 277
Likes: 0
Received 0 Likes
on
0 Posts
CM, the down grading was the sustained turn and acceleration, wasn't it?
Though it seems we aren't that fussed about it
ParlInfo - Parliamentary Joint Committee on Foreign Affairs, Defence and Trade : 16/05/2013 : Department of Defence annual report 2011-12
as to the other data need to write in the reams of paper. (posted on the last page)
Though it seems we aren't that fussed about it
ParlInfo - Parliamentary Joint Committee on Foreign Affairs, Defence and Trade : 16/05/2013 : Department of Defence annual report 2011-12
Air Vice Marshal Osley : The points that the Director of Operational Test and Evaluation made there about the manoeuvrability, as you point out it was the sustained turn and the transonic acceleration. He pointed out that the targets that have been set for those parameters were not going to be met by the F35. The figure of I think it was 55 seconds for transonic acceleration, the F35 was going to take 63.9 seconds to do that. That is obviously at a certain altitude, I think it was 30,000 feet, and a range of mach 0.8 up to mach 1.2.
The point to make about those is that that acceleration by the F35 is in a combat configuration. If you look at the legacy aircraft and we talk about comparable performance, a legacy aeroplane would require weapons and, obviously, external fuel tanks to be in combat configuration.
Dr JENSEN: Air Vice Marshal, sorry to interrupt you, the basis of my question—
Air Vice Marshal Osley : Chair, can I finish that one off?
CHAIR: Let the Air Vice Marshal finish his answer, then proceed.
Air Vice Marshal Osley : If we compare those two, the legacy aeroplane with fuel tanks and weapons on it, if we take a fourth generation fighter, typically an F16 or an F18, in that configuration it would take substantially longer than 63.9 seconds. If you took a 4½ generation aircraft it actually could not accelerate to supersonic in any time over that 0.8 to 1.2 range with a combat configuration of external tanks and weapons. The point I made originally was that we need to talk apples and apples between legacy fighters and the F35 on manoeuvrability and performance capabilities.
............
Dr JENSEN: I guess my concern is that the numbers that we were talking about, the numbers that the JPO has asked the JROC to reduce them from, are actually threshold numbers. They are not the desired numbers; they were the bare minimum threshold specifications. They did not reach it, but more to the point you had this group APA which actually accurately predicted what those numbers were going to be, in stark contrast to what Defence, Lockheed Martin and all those other organisations were saying. My question is: what does that say about the fidelity of the modelling and the analysis that is undertaken by all those organisations when you can get a small organisation getting the numbers right but all of those that are involved with the JSF have got them so wrong?
Air Vice Marshal Osley : The way that the requirements for the F35 were set up is to talk about mission performance. Mission performance specification is the high level. There is no doubt at this time about the F35 meeting that mission performance—that is, the ability to counter certain threats that might be encountered at IOC and into the future. That level of the specification remains as valid; we are not questioning that; it is actually achieving that. Below that you have your key performance parameters. The aeroplane at this point in time is achieving those, as far as the F35A is concerned.
The figures that you are talking about, the specifications down the bottom with the sustained turn and the transonic acceleration, are derived values in order to meet the overall mission performance specification. We have always been focused on the ability of the aeroplane to meet the overall mission performance specification—the ability to do its air-to-air mission and to do its air-to-ground mission. If you take a particular parameter, such as the transonic acceleration, the difference between—in fact, the F35 can reach mach 1.16 in 55 seconds, so it is 0.04 mach short of that target, and in a slight descent it will exceed the limit.
The point to make is that we do not necessarily get too focused on those individual derived parameters. We are focused on the overall ability of the platform, trading off everything—all the different capabilities—it has there: the situational awareness, the performance of the radar, the performance of the electronic warfare capability, the performance of stealth, the balance of range mission payload and the weapons.
The situational awareness is really the key—taking that and seeing how it performs against the overall mission specification. For instance, the trade-off that might have been made—the delay in the transonic acceleration—might have been due to giving it increased stealth as they were going through the design of the aeroplane. So you really need to see not the individual parameters but the overall specification. At the highest level, as I said, it is all about mission performance. That is what we do focus on.
The point to make about those is that that acceleration by the F35 is in a combat configuration. If you look at the legacy aircraft and we talk about comparable performance, a legacy aeroplane would require weapons and, obviously, external fuel tanks to be in combat configuration.
Dr JENSEN: Air Vice Marshal, sorry to interrupt you, the basis of my question—
Air Vice Marshal Osley : Chair, can I finish that one off?
CHAIR: Let the Air Vice Marshal finish his answer, then proceed.
Air Vice Marshal Osley : If we compare those two, the legacy aeroplane with fuel tanks and weapons on it, if we take a fourth generation fighter, typically an F16 or an F18, in that configuration it would take substantially longer than 63.9 seconds. If you took a 4½ generation aircraft it actually could not accelerate to supersonic in any time over that 0.8 to 1.2 range with a combat configuration of external tanks and weapons. The point I made originally was that we need to talk apples and apples between legacy fighters and the F35 on manoeuvrability and performance capabilities.
............
Dr JENSEN: I guess my concern is that the numbers that we were talking about, the numbers that the JPO has asked the JROC to reduce them from, are actually threshold numbers. They are not the desired numbers; they were the bare minimum threshold specifications. They did not reach it, but more to the point you had this group APA which actually accurately predicted what those numbers were going to be, in stark contrast to what Defence, Lockheed Martin and all those other organisations were saying. My question is: what does that say about the fidelity of the modelling and the analysis that is undertaken by all those organisations when you can get a small organisation getting the numbers right but all of those that are involved with the JSF have got them so wrong?
Air Vice Marshal Osley : The way that the requirements for the F35 were set up is to talk about mission performance. Mission performance specification is the high level. There is no doubt at this time about the F35 meeting that mission performance—that is, the ability to counter certain threats that might be encountered at IOC and into the future. That level of the specification remains as valid; we are not questioning that; it is actually achieving that. Below that you have your key performance parameters. The aeroplane at this point in time is achieving those, as far as the F35A is concerned.
The figures that you are talking about, the specifications down the bottom with the sustained turn and the transonic acceleration, are derived values in order to meet the overall mission performance specification. We have always been focused on the ability of the aeroplane to meet the overall mission performance specification—the ability to do its air-to-air mission and to do its air-to-ground mission. If you take a particular parameter, such as the transonic acceleration, the difference between—in fact, the F35 can reach mach 1.16 in 55 seconds, so it is 0.04 mach short of that target, and in a slight descent it will exceed the limit.
The point to make is that we do not necessarily get too focused on those individual derived parameters. We are focused on the overall ability of the platform, trading off everything—all the different capabilities—it has there: the situational awareness, the performance of the radar, the performance of the electronic warfare capability, the performance of stealth, the balance of range mission payload and the weapons.
The situational awareness is really the key—taking that and seeing how it performs against the overall mission specification. For instance, the trade-off that might have been made—the delay in the transonic acceleration—might have been due to giving it increased stealth as they were going through the design of the aeroplane. So you really need to see not the individual parameters but the overall specification. At the highest level, as I said, it is all about mission performance. That is what we do focus on.
Mr Burbage : We actually have a fifth-gen airplane flying today. The F22 has been in many exercises. We have one of the pilots here who flew it and they can tell you that in any real-world event it is much better than the simulations forecast. We have F35 flying today; it has not been put into that scenario yet, but we have very high quality information on the capability of the sensors and the capability of the airplane, and we have represented the airplane fairly and appropriately in these large-scale campaign models that we are using. But it is not just us—it is our air force; it is your air force; it is all the other participating nations that do this; it is our navy and our marine corps that do these exercises. It is not Lockheed in a closet genning up some sort of result.
Last edited by a1bill; 19th Feb 2016 at 03:44.
Join Date: Jan 2003
Location: Leicestershire, England
Posts: 1,170
Likes: 0
Received 0 Likes
on
0 Posts
a1bell, studiously ignoring, CM's question again I see...
Given the faintest possibility that you did actually miss it, here it is again-
-RP
Given the faintest possibility that you did actually miss it, here it is again-
Originally Posted by Courtney Mil
What have Typhoon and F-15 pilots said to you that is so different to that?
Join Date: Dec 2006
Location: UK
Posts: 799
Likes: 0
Received 0 Likes
on
0 Posts
Simulation Fidelity - and Uncertainty
CM and others,
Perhaps I might be allowed a short observation here.
CM's post about the complexity of the simulations now being used by the US and the UK for F-35 is illuminating. There are literally hundreds of parameters being fed into these programmes, and literally hundreds of different dynamic and tactical situations being investigated. Plus hundreds of different starting positions.
As well as these, there are literally thousands of assumptions being fed into these things. Many of them centre on the attributes of the 'foe' or 'adversary' weapon systems, plus their tactics. Some are intelligence fed, some are pure estimates.
Some of these simulations run without pilot input, many have 'pilot in the loop'. Some have other personnel 'operating' various friendly or 'foe' synthetic systems.
All these inputs have varying degrees of sensitivity. To exaggerate to make my point, I think it's a safe bet that your own missile's warhead effectiveness is a bit more significant than the thickness of your enemy's cockpit framing. But a lot of these inputs have a high degree of sensitivity.
So what? The 'so what' has to be uncertainty. Your aircraft might not achieve some of the parameters you initially assumed. (Such as F-35 sustained turn rate). Or your assumptions about enemy equipment or their tactics might be wrong. So how reliable are these simulations? Running them thousands of times, and feeding the results into what I understand are called 'Monte Carlo' algorithms, is claimed to reduce the uncertainties, but I always worried about the simple certainty of errors in the simulations. Plainly put, given the size of these things, the chance of incorrect code being entered has to be very high.
I had personal experience of a Farnborough simulation that was using wholly incorrect input data, tactics and assumptions. Plus some bad code. These had gone undetected for three years, and the results from it were influencing MoD decisions. The only reason they were found was that someone who had experienced similar issues in the US advised us to ask the same questions of the UK team doing the sim work.
Yes, these simulations can be used to estimate changes in combat effectiveness, and to derive estimates of loss ratios. But that's all they are. Estimates. Really numeric, complicated, high end guesses. But for aircraft like F-35, where we can't really send four of them up against four real Shenyang superjets, and see who lives, simulations are all the people driving these programmes have.
I'm not 'pro' or 'anti' sim. They are an essential tool, and very valuable if used well. In many areas, they are all the decision makers have. But I do worry that some people think that the more complex a simulation is, the better it is. I'd be more worried about errors.
As far as F-35 goes, (and I'm not a pilot, so this is just my own opinion), the direction of travel that the F-35 has followed is the right one. Outright aerodynamic performance is no longer the dominant attribute required for effective combat - it's the ability of the platform to sense, gather information, use it, and deliver an effective weapon, while denying as much of that information as possible to the foe. The Sea Harrier FA2 was a very, very effective fighter in the 90s despite its very limited airframe capability, due to a great radar, good radar/missile integration, and a great weapon. Same went for the Tornado F3, once it had JTIDS and AMRAAM.
The F-35 has, from day one, gone for a balance of platform and systems capabilities that is not the same as that pursued for legacy aircraft. Is that right or wrong? I don't know, and I'm certainly not qualified to judge. Perhaps this thread could calm down a bit if a few more of us admitted that.
Best regards as ever to those who have to make the calls for real in the air and on the ground
Engines
Perhaps I might be allowed a short observation here.
CM's post about the complexity of the simulations now being used by the US and the UK for F-35 is illuminating. There are literally hundreds of parameters being fed into these programmes, and literally hundreds of different dynamic and tactical situations being investigated. Plus hundreds of different starting positions.
As well as these, there are literally thousands of assumptions being fed into these things. Many of them centre on the attributes of the 'foe' or 'adversary' weapon systems, plus their tactics. Some are intelligence fed, some are pure estimates.
Some of these simulations run without pilot input, many have 'pilot in the loop'. Some have other personnel 'operating' various friendly or 'foe' synthetic systems.
All these inputs have varying degrees of sensitivity. To exaggerate to make my point, I think it's a safe bet that your own missile's warhead effectiveness is a bit more significant than the thickness of your enemy's cockpit framing. But a lot of these inputs have a high degree of sensitivity.
So what? The 'so what' has to be uncertainty. Your aircraft might not achieve some of the parameters you initially assumed. (Such as F-35 sustained turn rate). Or your assumptions about enemy equipment or their tactics might be wrong. So how reliable are these simulations? Running them thousands of times, and feeding the results into what I understand are called 'Monte Carlo' algorithms, is claimed to reduce the uncertainties, but I always worried about the simple certainty of errors in the simulations. Plainly put, given the size of these things, the chance of incorrect code being entered has to be very high.
I had personal experience of a Farnborough simulation that was using wholly incorrect input data, tactics and assumptions. Plus some bad code. These had gone undetected for three years, and the results from it were influencing MoD decisions. The only reason they were found was that someone who had experienced similar issues in the US advised us to ask the same questions of the UK team doing the sim work.
Yes, these simulations can be used to estimate changes in combat effectiveness, and to derive estimates of loss ratios. But that's all they are. Estimates. Really numeric, complicated, high end guesses. But for aircraft like F-35, where we can't really send four of them up against four real Shenyang superjets, and see who lives, simulations are all the people driving these programmes have.
I'm not 'pro' or 'anti' sim. They are an essential tool, and very valuable if used well. In many areas, they are all the decision makers have. But I do worry that some people think that the more complex a simulation is, the better it is. I'd be more worried about errors.
As far as F-35 goes, (and I'm not a pilot, so this is just my own opinion), the direction of travel that the F-35 has followed is the right one. Outright aerodynamic performance is no longer the dominant attribute required for effective combat - it's the ability of the platform to sense, gather information, use it, and deliver an effective weapon, while denying as much of that information as possible to the foe. The Sea Harrier FA2 was a very, very effective fighter in the 90s despite its very limited airframe capability, due to a great radar, good radar/missile integration, and a great weapon. Same went for the Tornado F3, once it had JTIDS and AMRAAM.
The F-35 has, from day one, gone for a balance of platform and systems capabilities that is not the same as that pursued for legacy aircraft. Is that right or wrong? I don't know, and I'm certainly not qualified to judge. Perhaps this thread could calm down a bit if a few more of us admitted that.
Best regards as ever to those who have to make the calls for real in the air and on the ground
Engines
Join Date: Apr 2010
Location: London
Posts: 7,072
Likes: 0
Received 0 Likes
on
0 Posts
Monte Carlo simulations are fine if you have a good understanding of the inputs, the range of values, the distribution of those values and how each input may interact with the others
It doesn't give you a "right answer" but only a "most likely " distribution
It is a lethal technique if there are "Black Swan" event out there, or you don't understand the inputs and their interaction
Reading Engine's excellent post I'd say it was fine for canopy thickness issues but something to avoid for simualting opposition tactics etc.............
It doesn't give you a "right answer" but only a "most likely " distribution
It is a lethal technique if there are "Black Swan" event out there, or you don't understand the inputs and their interaction
Reading Engine's excellent post I'd say it was fine for canopy thickness issues but something to avoid for simualting opposition tactics etc.............
And any other point or question that is too difficult, Rhino.
A1B,
Your long quote completely misses the point, demonstrating that you either don't understand the issue at hand or that you just choose to ignore it. As it happens, the extract you've chosen this time does two things, it confirms that the acceleration time has increased and, if Osley's numbers are correct, that the problem may be worse than we thought. His waffle about legacy jets not doing any better and F-35 could meet the old KPP in a descent is a bit of a smoke screen.
Regarding simulation, as you've been told several times now, small changes in parameters can have a disproportionate effect on outcomes, so Osley has restated that the performance figures have changed since the simulation that claimed the famous LER was run and that there has been no revision to that claim from repeat simulations using the new acceleration time AND the reduction in sustained g from 5.3 to 4.6 - quite a marked reduction.
What is more alarming about his numbers that you quote is the roll off in acceleration approaching M1.2. He states that the F-35 can reach M1.16 in 55 seconds and concedes that it takes 63.9 seconds to M1.2. He is saying that it takes a further 9 seconds to accelerate by M0.04, which means the acceleration has dropped off to around M0.004/sec. In other words it has hit a brick wall.
Engines,
I completely agree with what you say there and I thank you for expanding on the points. In particular, as I have said before, simulation is good at assessing the effect of changes (as long as you only change one part of the overall system at a time), but not so good at producing direct fighter comparisons. And that is one of the main reasons I treat any claimed LERs with such caution.
Interesting that you should mention the coding errors in the DERA (then) and US sims and the F-3 with AMRAAM in the same post. I too discovered some issues in the dataset associated with those trials, which may have had a significant effect on the derived operational effectiveness. Fortunately the measured change in effectiveness was later shown to be "within tolerances". If anyone believes that all the millions of data points and lines of code are issue free then they are being badly misled.
A1B,
Your long quote completely misses the point, demonstrating that you either don't understand the issue at hand or that you just choose to ignore it. As it happens, the extract you've chosen this time does two things, it confirms that the acceleration time has increased and, if Osley's numbers are correct, that the problem may be worse than we thought. His waffle about legacy jets not doing any better and F-35 could meet the old KPP in a descent is a bit of a smoke screen.
Regarding simulation, as you've been told several times now, small changes in parameters can have a disproportionate effect on outcomes, so Osley has restated that the performance figures have changed since the simulation that claimed the famous LER was run and that there has been no revision to that claim from repeat simulations using the new acceleration time AND the reduction in sustained g from 5.3 to 4.6 - quite a marked reduction.
What is more alarming about his numbers that you quote is the roll off in acceleration approaching M1.2. He states that the F-35 can reach M1.16 in 55 seconds and concedes that it takes 63.9 seconds to M1.2. He is saying that it takes a further 9 seconds to accelerate by M0.04, which means the acceleration has dropped off to around M0.004/sec. In other words it has hit a brick wall.
Engines,
I completely agree with what you say there and I thank you for expanding on the points. In particular, as I have said before, simulation is good at assessing the effect of changes (as long as you only change one part of the overall system at a time), but not so good at producing direct fighter comparisons. And that is one of the main reasons I treat any claimed LERs with such caution.
Interesting that you should mention the coding errors in the DERA (then) and US sims and the F-3 with AMRAAM in the same post. I too discovered some issues in the dataset associated with those trials, which may have had a significant effect on the derived operational effectiveness. Fortunately the measured change in effectiveness was later shown to be "within tolerances". If anyone believes that all the millions of data points and lines of code are issue free then they are being badly misled.
Join Date: Feb 2006
Location: A lot closer to the sea
Posts: 665
Likes: 0
Received 0 Likes
on
0 Posts
So the real problem lies with the issue of how these results, or any information, is presented into the public domain by both pro and anti F-35 media articles. The articles do not discuss the grey areas and details of the pros and cons of simulation vs reality as they push for attention grabbing headlines and hyperbole. I'm not blaming the journalists, more the style of modern media communications. The political and financial issues which circle this aircraft only put fuel on the fire.
Picking up on a few recent points regarding contractor support - it was/is not unusual to take contractors with you on large exercises/events. Examples from my own experience include taking BAES radar reps and Rolls-Royce reps to places like, Malaysia and Vegas on Flying Fish and Red Flag as well as taking them to sea on the CVS. By this point Sea Harrier FA2 was a very mature platform with plenty of extremely experienced blue suit engineers and pilots, but taking the reps gave another layer of confidence and easy access into the Comapny resources. Given the current maturity of the F-35A and the experience level of the Italian Air Force it makes perfect sense to use as much experienced contractor support as was available. Likewise the upcoming detachment to Mountain Home. Crawl, walk, run is an often repeated mantra and yet the push from some quarters would appear to be for all 3 variants of the F-35 to stop crawling and start running at about Varsity level.
Picking up on a few recent points regarding contractor support - it was/is not unusual to take contractors with you on large exercises/events. Examples from my own experience include taking BAES radar reps and Rolls-Royce reps to places like, Malaysia and Vegas on Flying Fish and Red Flag as well as taking them to sea on the CVS. By this point Sea Harrier FA2 was a very mature platform with plenty of extremely experienced blue suit engineers and pilots, but taking the reps gave another layer of confidence and easy access into the Comapny resources. Given the current maturity of the F-35A and the experience level of the Italian Air Force it makes perfect sense to use as much experienced contractor support as was available. Likewise the upcoming detachment to Mountain Home. Crawl, walk, run is an often repeated mantra and yet the push from some quarters would appear to be for all 3 variants of the F-35 to stop crawling and start running at about Varsity level.
The F-35 has, from day one, gone for a balance of platform and systems capabilities that is not the same as that pursued for legacy aircraft. Is that right or wrong? I don't know, and I'm certainly not qualified to judge. Perhaps this thread could calm down a bit if a few more of us admitted that.
Join Date: Aug 2014
Location: New Braunfels, TX
Age: 70
Posts: 1,954
Likes: 0
Received 0 Likes
on
0 Posts
What a concept: optimizing a system rather than one feature. Who'd have thunk it?
When it comes to pure good looks, though, I probably cannot be trusted due to long rotary wing experience and the belief that being so ugly that the ground repels them is not how helicopters actually fly. For my money, the V-22 is not good looking (the V-280 will be when it gets flying) but it seems to work pretty well.
That latest arsenal ship, Zumwalt class, doesn't look good. I really don't like it's looks, but I suppose it will work out in the end. (It better, those things are freaking expensive).
Likewise with the F-35. I don't really like its looks, but I suspect it will work out in the end.
Join Date: Sep 2012
Location: England's green and pleasant land
Posts: 697
Likes: 0
Received 0 Likes
on
0 Posts
I suspect you're 100% correct Lonewolf.
It'll work very well because those that work hard will make it so. I hope the criticisms can stay with the movers and shakers who have allowed things to get where they are. I hope the criticisms can stay away from those operating it. One only has to look at how pilots who praise it are berated on this forum, and others, to realise that some people just wanna vent their disgust at anyone who will listen.
The Atlantic trail is a clear example.
It'll work very well because those that work hard will make it so. I hope the criticisms can stay with the movers and shakers who have allowed things to get where they are. I hope the criticisms can stay away from those operating it. One only has to look at how pilots who praise it are berated on this forum, and others, to realise that some people just wanna vent their disgust at anyone who will listen.
The Atlantic trail is a clear example.