David Axe is More Boring Than Ever (Bless His Heart)

And still practicing Punk Journalism 

Bumped! Axe Doubles Down

*******Update 2 at End of Original Post******* 

Gawd. Saw this at work today and am only posting a short comment because somebody (surer than sh*t) will read something into any non-comment on my part, considering how I've already provided input (17 March 2015) on this subject:

I will bet dollars to donuts that IF the program chooses to respond to such hooey, that we will discover the first two BFM "tests" were in the middle of January, the first two flights were on two consecutive days, the missions were flown by two different pilots, and both of them had nothing but glowing reviews about the jet's performance. If I find eventually a public source to validate this 'guess' I will be happy to also share who I 'guessed' were the pilots, which flight they flew, and which plane(s?) was/were flown. And perhaps even quote the pilots.

First, I'm certain that whatever the test pilot report being cited by Axe may bear some faint resemblance to Axe's representation of same. Axe's perversions of the facts, per his usual modus operandi come via his bizarro assertions-stated-as-fact  and their complete disconnect from any reality as to the purpose and goals of the first A2A scenarios that were flown.

What the objectives were came out shortly after I made my first comments. From Av Week online (2 Apr 15), and with important bits in bold/EMPHASIS:

The F-35 Joint Strike Fighter has been flown in air-to-air combat maneuvers against F-16s for the first time and, based on the results of these and earlier flight-envelope evaluations, test pilots say the aircraft can be cleared for greater agility as a growth option. 

Although the F-35 is designed primarily for attack rather than air combat, U.S. Air Force and Lockheed Martin test pilots say the availability of potential margin for additional maneuverability is a testament to the aircraft’s recently proven overall handling qualities and basic flying performance. “The door is open to provide a little more maneuverability,” says Lockheed Martin F-35 site lead test pilot David “Doc” Nelson..... 

..... “When we did the first dogfight in January, they said, ‘you have no limits,’” says Nelson. “It was loads monitoring, so they could tell if we ever broke something. It was a confidence builder for the rest of the fleet because there is no real difference structurally between AF-2 and the rest of the airplanes.” AF-2 was the first F-35 to be flown to 9g+ and -3g, and to roll at design-load factor. The aircraft, which was also the first Joint Strike Fighter to be intentionally flown in significant airframe buffet at all angles of attack, was calibrated for inflight loads measurements prior to ferrying to Edwards in 2010.

The operational maneuver tests were conducted to see “how it would look like against an F-16 in the airspace,” says Col. Rod “Trash” Cregier, F-35 program director. “It was an EARLY look at any control laws that may need to be tweaked to enable it to fly better in future. You can definitely tweak it—that’s the option.”

The expectation of the tests was to see how the airplane behaved when slung about in a A2A engagement using the current control laws within the current G-limit design, and they found they can open them up the laws for more. Let's ignore the fact we don't know AF-2's empty weight and that the program was delivering the SDD baseline weight aircraft about the time the engagement occurred.

Let's pretend it doesn't matter that we don't know the weight of the F-16 or the altitudes and speeds the engagements occurred either. Let's also ignore the fact that ALL jets need to have many such engagements before the aircrew really know how to best exploit their advantages. Even without all that, Axe is STILL  just laying down a nice pile of fertilizer for the rest of the Punk Journalists and Faux Reformers to spread and nurture yet another disinformation cascade.

Sit back and watch the fun. Any bets on who cites this weak-a** hit-piece first?

Update: I see F-16.net is on the case.

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Update 2(1 July 15)

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Wow. A lot can happen in a day, and I can't even go into the kind of detail I'd love to go into for some of it. (I'll have to stay 'hypothetical' about the now-out-in-the-open Test Report, given the caveats plastered at the top and bottom of every page of the report.)

First. A former fighter driver with experience in both the F-16 and F-18 chimed in with some thoughts that fit pretty much hand-in-glove with what I've stated so far in his post: Why The “F-35 v F-16″ Article Is Garbage.
 
Second. The global disinformation cascade Axe set off (and I predicted) was gathering a lot steam until the former fighter driver posted his thoughts.

Third. The F-35 program office and LM then added some information that was also consistent with my posts on the topic. (I'm not claiming any special insight here, just an experienced one that appears to be consistent with other experienced viewpoints.)

Fourth. Axe appears to have felt enough sting in the criticism he's received so far to now have gone a step further and posted a lightly-sanitized copy of the report. If he cared a whit versus just playing a gadfly, I would love to explain to him the cognitive dissonance between what the report says and means in contrast to what he asserts it means. I suspect the JPO or LM will have to go through the process of releasing some of the leaked information for export just so they can spell it out for the low-information crowd.

Until they do, I won't be linking to or addressing anything directly mentioned in the report because doing so could constitute an 'export'. I like my current digs and income status and look terrible in orange or broad stripes, so NO.
Axe better hope he's as insignificant a pissant as I think he is, because the caveats on those pages obviously leave him and his employer open to criminal prosecution and civil lawsuits. It would take a lot of political capital to be spent by the anti-defense crowd to keep Axe and Co. out of the grinder if Uncle Sugar or Lockmart decide to call them out on this. BTW: May whoever leaked the report be far less connected and may the scum twist in wind over this leak.

Given I won't be discussing the contents of the report, I WILL say that Axe's doubling-down on this stupidity gives me some inkling as to how Forest Rangers must feel when some life-long urbanite visits the park and keeps pointing at some small woodland creature insisting it is a 'bear' no matter how many times the Ranger points out the differences. I can't believe he offered the report as if it supported his position. Is he THAT clueless, or is he 'whistling past the graveyard' hoping nobody will call him out further on his peddling crap?

Maybe he wouldn't have made this mistake of misreading things into the report that aren't there, if he read more widely.


      

An Open Letter to Ed Driscoll: Power of CAS Myths

Guest 'Pundit' at Instapundit, Ed Driscoll, links to a craptastic "Save the A-10" editorial (unattributed) at Investors Business Daily.... SIX MONTHS after it was published?

I thought the editorial at the link was so bad at the time it came out (along with a bunch of similar A-10 puff pieces), I don't remember paying it much heed.  But Driscoll's resurrection of this poorly 'informed' op-ed illustrates--- once again-- the power of the CAS Mythology and "narrative". Just look at the comment thread at Instapundit. Yikes!

Normally, I like what Ed Driscoll writes, and writes about, but he's waaay out of his area of expertise this time.

Dear Ed: That IBD Op Ed could have been written by one or more squirrels.  

No, the A-10 wasn’t designed to stop Soviet Tanks. This is a common misconception I've heard General Officers utter. We are so ahistorical.

The A-10 was conceived as a weapon that could attack “hard targets” and cooperate with Army Airmobile forces in SEA. After Vietnam, the Air Force HOPED it could be survivable in the NATO order of battle and did all kinds of things to make/keep it relevant. In Europe, its main advantage was the ability to get below typical rotten Euro-weather that would keep fast-movers off the target. We have sensors and communications now that remove the weather restriction for fast movers. the F-35's The weapons the A-10 was designed to survive against predated MANPADs, Integrated Air Defense Systems and even radar controlled AAA that even the NVA were pushing into the South at the end of the Vietnam War. (Google Lam Son 719).

The A-10 wasn't fielded in 1972. It first flew, in a fly-off, in 1972. (I was there) It didn’t hit IOC until 1976 or FOC until 1978.  Core operational concepts for Europe weren't developed until 1979 (I was there too).

The A-10 HAS to fly low and slow because it doesn’t have the kinds of sensors (SNIPER pods are an improvement, but not enough) and communications capabilities to sort out the battlefield well prior to the attack. It often HAS to loiter longer just because it takes longer to set up an attack.

The cockpit armor and other design features make it harder to shoot down that it would be otherwise, but having bits and pieces shot off you is not a long term survival strategy. A-10s in Desert Storm saw the most intense air defense environment they have seen before or since. They did not do well. A-10s were pulled off the Iraqi Republican Guard units and tasked against weaker units as a consequence.

Yes “A supersonic fighter pilot flying miles above the battlefield will not see enemy forces the way a Warthog pilot can” – They will see it better. I’m always fascinated by people who cite 'low and slow" as an advantage: as if flying there gives one more time to view the ground. That maybe true at Piper Cub speeds. But I’ve 'done' low and 'A-10 slow' a the same time and the scenery is whizzing by pretty fast. It ain't that great for picking up and following specific specs out of all the other specs.

A fast mover may cost more $ up front, but if the attrition rate is even a few percentage points lower, the savings, not to mention the ability to sustain operations, far outweighs the operating costs—even if you don’t factor in the fewer 'dead aircrew' part. THAT is the proper context for framing a statement like “Force requirements should be dictated by battlefield requirements, not budget restraints.”

The F-35 will provide CAS in its own way and not in the manner the A-10 provides it, so the open question is not whether or not the F-35 “can take the punishment the A-10 can”. The open question is:

Why do people think you have to take punishment like an A-10 to fly CAS?

The Warthog is still a low-intensity-conflict “hammer”: A Completely appropriate design (ignoring they are worn out) solution if ALL you are going to do is flatten insects. It is NOT so appropriate if you have to also be ready to face  Thor who is swinging his own hammer. Unless you have the extra dollars to buy and support both kinds of weapons systems to deal with bugs and Old Norse deities, you want the one that can beat the gods without getting beat yourself.

May I Suggest Some Remedial Reading?
Start at Part 1 (Links for Part 2 through 8 at bottom of Part 1).

Just found out where and how Driscoll got suckered in.
~Sigh~

Weird Days for the 'Death Spiral' Eh?

While there's really no question as to how the "Who's Death Spiral is It?" game is going to be inevitably played out from where I'm sitting, it looks like The Borg and their F-18E/F are going to get at least one more year without too much loss of altitude via the generosity of Congress. But that generosity is not being granted exclusively to just the F-18:

The vote was 278-149 in favor of the bill, which drew stiff opposition from Democrats because it uses a war-fighting account to raise defense spending next year. The measure provides $8.4 billion for 65 next-generation F-35 fighters, eight more than requested by the Pentagon, as well as $16.9 billion toward nine Navy ships.
In the Senate, the Appropriations Committee approved a $576 billion defense bill that also boosts spending on the F-35 program and adds funds to speed replacement of a Russian-made engine used to launch U.S. satellites.
The Senate bill would increase the number of F-35s made by Lockheed Martin in Fort Worth to 67 from the 57 requested in fiscal 2016. It would shift $730.3 million to buy six additional Marine models of the F-35 and add $97.6 million that, when combined with other previously approved but unspent funds, would buy four additional Air Force models, according to the bill report.
The Senate measure for the year that begins Oct. 1 would also add about $978 million for 12 F/A-18 E/F Super Hornet jets made by Boeing Co., rejecting the Pentagon’s plan to end Navy purchases of the plane.

Everyone's a winner!

The F-18 buy doesn't bug me all that much. Yeah the Taxpayer pays (again), but it may be worth it, if only as a wedge to help keep LM's F-35 on the cost reduction slope, And its not as if the Navy isn't going to use up the F-18E/Fs they already anyway even after they field the F-35C. Once the Navy catches up to the AF in fully exploiting LO aircraft however, those new F-18s may last years longer than planned: because they just won't be used all that much once it happens.

Speaking of Cost Reductions. 

Evidently the F-35 unit cost is ALREADY dropping due to LM's  ‘Blueprint’ To Drive Down F-35 Costs proactively, instead of just relying on Economic Order Quantities to survive Congress' penchant for micro-management and irrational change:

Initially, the manufacturer expected that it would see the first cost savings during F-35 low-rate initial production (LRIP) lot 9, which Lockheed Martin and the DOD were negotiating at the time of [Lorraine] Martin’s presentation in mid-February. But it realized early benefits while producing LRIP 8 airframes, cutting about $260,000 from the cost of each of 43 fighters that it will begin delivering in 2016. “So that’s not chump change,” Martin declared. “I rolled that cost savings into the offer I made to the government when I negotiated the contract,” which the parties signed last November...

...At the time of the LRIP 8 contract award, Lockheed Martin said the average unit price of airframes for the three F-35 variants was 3.6 percent lower than the LRIP 7 price. The company reports that the LRIP 8 cost of an F-35A for the U.S. Air Force without its F135-PW-100 engine was $94.7 million. The price of an F-35A with its engine was $108 million, which was $4 million lower than Lot 7 prices, according to the Pentagon’s F-35 Joint Program Office (JPO).
Martin said the manufacturing improvements her company is implementing could knock another $780,000 from the price of LRIP 9 jets. Ultimately, the blueprint’s goal is to deliver an F-35 with an engine for $80 million in then-year dollars, accounting for inflation. Martin has generated news by saying the price could be even less. “If this works, and we have confidence that it will, [the government is] potentially willing to invest on the tail end $300 million. With these two sets of investments, that’s what gets us down to under an $80 million aircraft,” she said.

Sweet!

Norway's First F-35 Leving 'Major Mate' for Final Assembly

Let's see what the URF cost of the 2016 F-18E/F buy is going to be in then-year dollars is when the next SAR covering the buy is  released. Should make an interesting comparison. At some point in time the mouth-breathers are going to have deal with the reality and stop amortizing F-35 sunk costs over future buys, but it won't be soon. I think they will want to pretend a little longer, if only because there isn't anything else big to b*tch about.

The One DOT&E, er DoD SAR Quote You Probably Won't See Anywhere Else

Now with Don Bacon! 
(As in Corrected, Updated and Bumped with Hat Tip to Same)

Don't expect the Punk Journalists, Loyal Babblers, or Faux Reformers (abetted by Punk Journalists) to bother with putting proper perspective around all their little doomsday accounts of what is going on inside the F-35 program. Remember, its all about either trying to kill a program and/or coming up with enough rent money. "P.A.C.E." is the vehicle that they'd drive off the cliff before they'd ever move away from it.

So there is one DOT&E DoD Selected Acquisition Report (SAR) quote out of all the reports and testimonies that comes out of the unexpurgated December 2014 (for 2015) DOT&E Report DoD SAR that I don't see anyone pushing out to the uneducated masses anytime soon. It is the final paragraph of the report's Executive Summary, Page 10:

In summary, the F-35 program is showing steady progress in all areas – including development, flight test, production, maintenance, and stand-up of the global sustainment enterprise. The program is currently on the right track and will continue to deliver on the commitments that have been made to the F-35 Enterprise. As with any big, complex development program, there will be challenges and obstacles. However, we have the ability to overcome any current and future issues, and the superb capabilities of the F-35 are well within reach for all of us. 

Everything else in the media that surrounds the F-35/DOT&E, DoD SAR, GAO, blah ,blah, blah, reportage is about either rallying the mouth-breathers or herding the sheep.

About the Update: I had meant to identify the report I linked to as the SAR, but let myself get in a hurry and used the incorrect reference at the link that originally led me to the document instead. My 'bad', but it doesn't change the essence of the post or the point either. This update exists because I loathe inaccuracies, even mine and no matter how they are identified.
If anything, the quote is more relevant to my point coming from the SecDef Office SAR than the DOT&E annual report:

F-35 Transonic Acceleration vs. an F-16 Block 60 'Hot Rod'

UAE's Block 60 in early livery
over the Arizona Desert (original source)

Updated (at bottom of post) and 'bumped'

'Tim A,' in the comments of my last series of posts covering F-35 KPPs and 'Transonic Acceleration', piqued my interest in doing a comparative analysis of the F-35A's transonic acceleration KPP against a hypothetical, lightweight Block 60 F-16E that LM built for UAE. We can only 'estimate' and in the case of the F-16E/F the estimates can, I believe, be regarded as fair approximations since they are based upon F-16 Block 50 data in hand. Excursions away from the F-35 KPP data will be more presumptive, but we will not venture too far away from 'firmer ground'.

To do the comparison that we want to do, will first require us to make some reasonable assumptions (and remember they are assumptions) concerning the Block 60 aircraft and how they differ from, or are materially the same as, the more well-known Block 50 aircraft.

Major Differences between Block 50 & 60 Aircraft 

There is little 'hard' data available beyond certain basic information on the Block 60 configuration. The United Arab Emirates funded the development of this version in its entirety, and there is no 'Dash 1' manual in the public domain (that I am aware of) that could provide us with the 'authoritative' source for the information we seek. In any case, the factors most important to our discussions will be the establishment of an acceptable aircraft empty weight, and evaluation on what effect the Block 60's higher thrust engine (32,500 lbs vs 29,000 lbs of thrust in afterburner) would have on overall performance.
A major factor that might warp our evaluation of the Block 60 against the F-35A KPP performance--if we let it --would be quantifying the effect of wave and other drag differences between F-16 Block 50 and Block 60. My approach will be to do so in a manner that passes the "Reasonable Man' test.
As the purpose of this exercise is to get an idea as to  how well the 'future' (i.e. F-35A) stands up in comparison to the 'present' (aka F-16 Block 60), I intend to give the Block 60 performance every reasonable benefit of the doubt in surveying the drag differences between the Block 50 and Block 60. I choose to do so in part because I expect the non-wave drag differences between the Block 50 and 60 aircraft will be seen as less important compared to the wave drag contributions. (This should be seen as reasonable, if only because of the relative contributions of the factors proportional to the drag total). I do not expect to be able to characterize the effect of the differences exactly, but we should be able to identify the differences and their effect within a comparatively narrow range with the data in hand.

Block 50 vs Block 60 F-16 Drag and Weight Differences

For our earlier F-16C Block 50 comparison to an F-35A KPP configuration we used this Block 50 configuration:

F-16C Baseline: Full Internal Fuel, 2 AMRAAMs on wingtip launchers and full 20mm load.

The table above was just for a 'baseline' configuration. The source document for the data actually provides us with a wealth of information concerning many different F-16C/D weight and drag configurations that effectively define the F-16C/D transonic performance across a wide region of weight/drag possibilities: 

F-16 Block 50 Drag Count and Weight Differences.
Note that at low drag counts the differences in weights have a greater impact on acceleration times than the differences in drag, In particular, the increases in acceleration time due to a DI below 30 are small (interpolation looks like ~5-6 secs at 32K lbs)

We'll use this information to characterize the effect of the Block 60's external configuration and weight on its total 'drag'. 

For this exploration, we have selected a slightly "better armed" F-16E Block 60 configuration: 

F-16E Block 60 Configuration: Full Internal fuel load not includng CFTs,
Empty CFTs, 4 AMRAAMs and full 20mm load 

The four AMRAAM load was suggested by 'Tim A,', though I kept the CFTs empty because I wanted to keep the Block 60 configuration reasonably light.

The drag differences between the Block 50 and Block 60 F-16 configurations are reduced to the effect of the Block 60's greater total weight and increased drag profile. For the drag numbers in the selected Block 60 configuration I'm using the HAF F-16 manual and an article on CFTs found here. The CFT article mentions specifically the CFT set as "12%" of 300 gallon tank, but that is a general statement that may be the average drag reduction for the 300 in the subsonic region. I selected using 4 as the estimated DI for the CFTs for the transonic region, but even if it is less (perhaps '2') the difference between DI totals of 22 and 24 won't be seen in any guesstimate we can do. In addition, I have elected to treat the Block 60 basic airframe drag the same as the Block 50 in spite of the fact the Block 60 is designed to use and carry sensors/systems that are specific to the type.

Block 50 and lower pods on the left, Block 60 targeting system shown
on the bottom right. Some of the extra weight of the Block 60
comes from carrying an internal infrared search and tracking system,
of which only the FLIR ball can be seen just ahead of the canopy

These Block 60 systems, while they are no doubt 'lower drag' than the Block 50's 'add on' LANTIRN pods etc, they are also not "drag free". This is especially treu of the Sniper XR-derivative targeting system installation shown above. To give the Block 60 every advantage in the quantitative analysis, I choose to ignore the drag of the Block 60's unique installations. I do so for a couple of reasons. First, I doubt it will make as much 'drag difference' as accounting for all the weights involved, and second there is photographic evidence that while the Block 60-specific targeting system installations were initially expected to be carried all the time, in practice it hasn't always the case(Google "Block 60 F-16" and check out the photos). We'll just keep the 'drag factor' of these systems in the back of our minds going forward.

Block 50 vs Block 60 F-16 Engine & Thrust Differences

F-16 Block 50 Engine (source)

F-16 Block 60 Engine (source)

The differences between the Block 50 F110-129 engine and the Block 60 F110-132 engine are slight, but the -132 engine yields 2600 more pounds of thrust at sea level (standard day):
The key differences between the two engines that drive the increased thrust for the -132 variant aren't relevant to our analysis but for the sake of completeness, let us observe that the -132 has a slightly higher airflow than the -119, and that is at least partly due to the ever-so-slightly lower bypass ratio (more 'fast hot' air) for the -132 design. There are also some 'efficiency' improvements in the -132, some of which can be retrofitted to -129 engines for better durability if the users want to pay for the 'goodness'.
Normally, I would be loathe to try and extrapolate what a difference in engine thrust between planes would mean to the relative transonic acceleration performance, but given we are looking at essentially the same aircraft at different weights (and thrust to weight ratios), I think we can make a reasonable accommodation for the effect (on Block 50 acceleration) of the the extra thrust based upon looking at comparable Block 50 thrust-to-weight ratios. We can-- and WILL!-- apply that analysis to arrive at a fairly narrow region of impact of the higher thrust to the Block 60's transonic acceleration performance estimates.

Deriving an Estimation of F-16 Block 60 Performance Based Upon Block 50 Performance

We'll do this in a two-step process to bracket the likely transonic performance of the Block 60 compared to the Block 50. It doesn't make a difference in what order the process is applied, but we'll start with the simplest to explain first, and we'll just keep the F-35A KPP performance in sight as a sort of benchmark for now.

Step A: The Weight/Drag Impact 

As mentioned earlier, we can use the HAF T.O. GR1F 16CJ 1 1 Change 8 document containing the max acceleration performance data for the Block 50 to derive an approximation of the effect of the Block 60's weight and drag relative to the Block 50, We've approximated the drag index of the Conformal Fuel Tanks and added the known drag index of the Block 60's launchers and extra (2) AMRAAMs to arrive at a drag index 'upper' of  24 over a baseline Block 50. As this drag index is approximately halfway between a known DI=0 and DI=50, and the Block 60's selected configuration weight of 31,503 lbs is slightly lower than the the Block 50 32K lb configuration, the effect of weight and drag differences ALONE would indicate a transonic acceleration time of about 53 seconds (plus or minus). This is a performance better than the Block 50 at 32K lbs (DI=50) but not so good as a Block 50 at 28K lbs and with a DI=50 (obviously).

Note: This step would have been a lot easier to show/follow if the Block 50's DI=0 performance at 28K and 32K lbs were 'feasible' configurations. We could have just bracketed the DI=0 and the DI=50 values for a 32K weight.         

Estimating the Effect of Block 60 Weight Drag ONLY based upon Block 50 data. 

As we observed earlier within the 'F-16 Block 50 Drag Count and Weight Differences' chart, large aircraft weight difference have more effect on acceleration times than Drag Indexes when Drag Indexes are low:

Effect of Low Drag Count at relevant weights

Step B: The Impact of the Engine Difference

This step is a little more involved than the other. We again will rely on using the Block 50 data from HAF T.O. GR1F 16CJ 1 1 Change 8, but in estimating the impact of this factor we have to normalize the data for the Block 50 before applying it to the Block 60.

In the first section of the following graphic, I have charted the relative thrust-weight values for both the Block 50 and Block 60 aircraft. Notice how close  both the absolute values and the relative step functions are for the highlighted ratios shown for each F-16's Block data. The highlighted Block 60 ratios and step functions are slightly lower than the Block 50's but still very close.

If we ignore all other differences between the ircraft and assume acceleration differences are purely a matter of thrust to weight, and  generously assume all increased thrust-to-weight for the Block 60 translates proportionally into better acceleration at every weight AND look at the acceleration times for the Block 50 configurations between weight steps, we can express those step 'time deltas' for the Block 60 as a function of the ratio of  Block 50/Block 60 thrust ratios times the time deltas for any selelcted drag index. If that sounds confusing, it is because it is...without a spreadsheet.

To simplify, for this specific example I divided the 'Raw' Block 50 Thrust-Weight Ratio for the 28K weight by the 'Raw' Block 60 thrust-Weight Ratio for the 32K weight (1.0357143/1.0156325). I then  treated the Block 50 28K DI=24 acceleration time shown in the 'Normalized for Drag' portion of the chart below as being solely a product of thrust-to-weight, multiplied the Block 50 acceleration time for the 28K weight (44 seconds) times the 'ratio of thrust ratios used.

Stated more clearly without an audit trail: We assume the heavier block 60 will accelerate like a Block 50 at the same thrust to weight ratio. 

I am giving the Block 60 further benefit of the doubt by not accounting for the higher weight, but that's OK!: we're estimating remember?

Plotting the Step B as standalone estimate on the same graph with the Part A standalone estimate we find:

Estimating the Effect of Block 60 Weight Drag ONLY (A) and Block 60 Thrust to Weight ONLY (B), based upon Block 50 data. 

Obviously the actual Block 60 performance should fall somewhere between the outcome for each as independent factors:

Block 60 Transonic Acceleration Estimate: A Near-32K pound Block 60 with 4 AIM-120s accelerates like a Block 50 F-16 DI=50 at 28K Lbs.   

So in the end, the big advantage of the Block 60 aircraft appears to be the increased range and better/equal performance at a slightly higher weight than the Block 50. Nothing to sneeze at, but nothing too surprising either.

But HEY! What about the Block 60 in comparison to the F-35A KPP performance? 

We've covered the whole F-35A configuration setup already elsewhere. The big thing we do not really 'know' still is how much fuel is aboard the F-35 for the KPP measurement. We DO however understand that the KPP was written based upon a load of two 2K Lb JDAMs and 2 AMRAAMs carried internally. If we simply swap the two JDAMs for two more AMRAAMs the F-35A's weight would be about 4,000 pounds less (Most 2K Pound JDAMS weigh more than 2K lbs with the kits).

This F-35A KPP configuration performs almost exactly the same as a 36K pound Block 50 with a DI=50, the removal of 4000 pounds of weight should yield performance approaching that of a 32K pound Block 50 with a DI=50:

If the F-35A in an A2A configuration wants to match this F-16 Block 60 A2A configuration in transonic acceleration, it can probably just dump some fuel, or more likely simply 'unload'.  Conversely, in an A2G configuration similar to the F-35A KPP setup, the F-16 Block 60 would probably fair not so well against the F-35A KPP configuration

I'm not even going to plot this one (DI=74? Yikes!)

Housekeeping: Note that the Block 50 data in hand starts the acceleration run at Mach .79 and not the Mach.8 used for the F-35 KPP performance. That's OK! At the weights we are looking at, this translates to about 1 second or less difference: well within any margin of error.

*********************************************************

Update 29 April 15: About the presumed KPP configuration

(This ‘Update’ driven by conversation in the thread, because covering all the aspects of a complex subject in a comment thread is futile)

It doesn’t really matter if the F-35A configuration for the transonic acceleration KPP includes 2 JDAMs or if the JDAMs have already been dropped. It really doesn’t matter for three fundamental reasons, only one of which we’ve discussed in any detail.

First Fundamental Reason: Ambiguity of KPP Configuration

The KPP configuration and weight ‘is what it is’, and all our analysis has been focused on the relationship between those factors that affect transonic acceleration, and how (and how much) changes to those factors affect performance.

We do not ‘know’ the payload carried for the KPP values for any of the explorations we’ve made, and I’ve been comfortable in doing these parametric examinations using the assumption that the internal payload for the F-35A consisted of (2) 2K JDAMs, (2) AMRAAMs and a nose load of 25mm cannon rounds. Unlike an F-16 or any other aircraft that carries bulk fuel and weapons externally, it really didn’t matter what the F-35 was carrying internally from a drag POV except as in how whatever weight the F-35 was bearing increased the drag due to lift. While I used the assumption that the plane was carrying the JDAMs, We’ve never asserted or implied a total F-35 weight as the basis for the estimates. We have seen that at whatever the baseline weight basis is, the F-35A in its KPP configuration (whatever that is) accelerated from M.8 to M1.2 very much like an F-16 Block 50 at 36K lbs and a Drag Index =50.

I then posed a ‘what if’ scenario where the F-35A was 4K Lbs (or so) lighter to estimate performance at an “X”-4K pound F-35A. I took away the hypothetical 2k JDAMs because they were convenient to quantify. This is acceptable because, as I have mentioned many times, these analyses are about gaining an understanding of the factors involved and their impact/effects.

The data in-hand can’t be used to prove anything either way, it can only point to ‘possibilities’.

I am completely agnostic as to whether or not the F-35A KPP includes carriage of the JDAMS. If, as it has been suggested by ‘Tim A.’ in the comments that the KPP weight of the F-35 for the transonic acceleration performance does NOT include the 4K+ of JDAMs, I am good with that. BUT, I still cannot make a claim either way with certainty. If one takes at face value [1] then-Commander Bowman’s statement that

“The fuel levels and payloads at which maneuverability is calculated differs for each variant but generally focuses on a post-weapons release payload and fuel state at 50% of the required combat radius”

…do we assume that the transonic acceleration KPP falls within both the “post-weapons release” AND “50% fuel” ‘generalities’, or just one? Or the other? Or neither?

We don’t know. 

Looking at the key table in the Bowman paper….


We see two distinct CTOL (F-35A) loadouts specified for two KPPs in the footnotes. Are these the only two ‘possible’ exceptions to the “general” configuration to which Boman refers, or are they the ONLY exceptions? Are they just configurations that Bowman highlighted because he thought they were important to his arguments? We don’t know.

I’ve always been struck by the reference to the 2 empty external tanks in the first footnote, given the F-35 at this time does not carry external wing tanks and to-date they have not been seen as ‘value-added’ enough to be pursued by the program (an interesting topic for another time), but of interest to our discussion here is the second footnote as it relates to Bowman’s introduction to the table.

If it is worth mentioning in the footnote that “60% of internal fuel load” is carried as an exception to the ‘general’ rule, why would it be worth mention that the JDAMs had been “jettisoned/released” as if it were not part of the ‘general’ rule as well? I believe there is enough incongruity between the text and the table to prevent anyone from asserting the F-35A’s transonic acceleration KPP configuration MUST include or exclude JDAMs OR must be at 50% or 60% (or ‘n%’?) fuel [2] carried. This ambiguity is the primary reason I resisted establishing a baseline weight for the F-35A in doing the acceleration modeling and analysis. (Observant readers will note the only time I quantified F-35 variant weights in looking at the F-35 acceleration performance was when we examined possible discriminants between variants as drivers for variations in acceleration times.)

To go beyond the point that we have already gone can only add more uncertainty. Which leads us to Fundamental Reason #2

Second Fundamental Reason: The F-35A Baseline Design Itself is NOT Final

And the ramifications of this point are HUGE. Much of it relates to what will be the final weight/drag of the aircraft itself, but some of it relates to how the ‘books’ are being kept that prevent any definitive performance statements until SDD is complete (see Reason #3).

The weight uncertainty factor we touched upon under Reason #1 looms larger than many people might realize. We can assume all KPPs are based upon all or part of a fuel load required to achieve some unknown-to-us mission utility, objective and/or point, so weight is a factor in all KPPs.

Aircraft total weight will be driven by Aircraft Empty Weight, Fuel Weight, and Payload Weight. To meet ANY KPP objective listed, changes in the basis for Aircraft Empty Weight will have a compounding effect on total weight; creating a fuel-weight ‘spiral’ that can be positive or negative. The lighter or heavier the aircraft, the more or less fuel weight will need to be carried, and reciprocally, less or more payload can be carried. For every pound of empty weight added, how much more fuel weight is needed or how much payload weight will be affected? (Answer: “It depends”.) Whatever a percentage of fuel load weight used for each KPP, and the primary driver for specifying a max weight for each variant appears to vary [3], it can only be of importance as part of a total weight (assuming all weight is carried internally for all KPPs allowing us to ignore external drag ‘adders’), and what we do NOT know about this value and how it relates to performance parameters far outweighs what we do know. Keep this in mind going forward, as the first thing that we DO know about the F-35A’s empty weight is that it is currently below design objectives (DOT&E FY14 PDF):

Weight management of the F-35A is important for meeting air vehicle performance requirements and structural life expectations. These estimates are based on measured weights of components and subassemblies, calculated weights from approved design drawings released for build, and estimated weights of remaining components. These estimates are used to predict the weight of the first Lot 7 F-35A aircraft (AF-72), planned for delivery in August 2015, which will be the basis for evaluating contract specification compliance for aircraft weight.
-- According to these reports, the program has reduced weight by 16 pounds in CY14 (from January to October estimate). The current estimate of 29,016 pounds is 355 pounds (1.2 percent) below the planned not-to-exceed weight of 29,371 pounds.
-- The program has demonstrated positive weight management of the F-35A over the past 38 months, showing a net loss of 123 pounds in the estimates from August 2011 to October 2014. The program will need to ensure the actual aircraft weight meets predictions, as well as continue rigorous management of the actual aircraft weight beyond the technical performance measurements of contract specification in CY15 through the balance of SDD to avoid performance degradation that would affect operational capability.

An empty weight that is 355 pounds lower than the modeled KPP weight implies a much larger weight in fuel that does not to be carried to achieve the F-35A’s combat radius (or ‘60%’ mission radius/endurance distance/time). JETA-1 fuel weighs 6.71 lbs per gallon. How many pounds of fuel can be left behind by not having to carry 355 pounds of dead weight over 1200+ nautical miles out-and-back? We don't know. the uncertainties are certainly adding up.

While the AF-72 aircraft is the target point that is “the basis for evaluating contract specification compliance for [F-35A] aircraft weight”, we also do not know how much margin is in the “planned not-to-exceed weight of 29,371 pounds” target weight. I’ve seen indicators[4] that prevent me from completely assuming the weight targets are the weight assumptions used for KPPs. If the targets aren’t the limits, then there is further weight margin that the KPP model may not be accounting for in performance modeling. I personally wouldn’t assume this to be the case, but we don’t know. Time will tell.

Third Fundamental Reason: The KPP Ground Rules and Assumptions and/or their Impacts aren't fully known or accounted for either.

The ‘unknowns-unknowns’ here might outweigh any factor we have examined in trying to compare an F-35A to any legacy aircraft. The 'known-unknowns' are bad enough. Example? We know the KPPs are based upon a ‘pessimistic’ engine performance with 5% thrust and fuel efficiency degradation (Ref #8 here). We do NOT know what impact that factor has on the overall ‘standard’ aircraft weight or acceleration, but just as important, we do not yet know if that the ‘engine of record’ in the models is the original 40K Lb thrust engine, or an engine with the newer 43K Lb thrust rating. So, what else do we NOT know about the model GR&As?

Finally,

I don’t lose any sleep over the F-35A’s transonic acceleration because in the end it still gets back to the fundamental fact that you can always just ‘unload’ the plane to shed all that wave drag due to lift… if you so desire. Using such a technique, the F-35A should be able to run away to, from, or with any current or future aircraft through the transonic region unless that other aircraft is heavier AND with a higher Thrust/Weight ratio, and there are always other ways to deal with such contingencies (TANSTAAFL). I’ll THINK about getting concerned when the JPO and users get concerned.

Notes:
1. While I used the Bowman paper data, I put no weight on what was discernible as Bowman’s own analyses or observations surrounding the data. I treated the paper in this way, because I cannot divine if his positions/opinions come from ‘fact’ or from his ‘views’ on the facts: especially since I see several assertions/conclusions (unrelated to any of the KPP discussions so far) within that I know are erroneous--if only through their over-simplification. Further, Air Command and Staff papers tend to be advocacy papers and Bowman’s certainly falls into that description. I know enough about ACSC papers to know that they are just like almost all college papers, they are usually done for a ‘grade’ and not posterity. False data can get you a failing score in ACSC, but I’ve not seen evidence that faulty reasoning will-- unless you argue it ineffectively.

2. As an aside, if I HAD to pick a fuel quantity for the transonic KPP I would pick a value above 50% fuel on the assumption that the operators would desire at least 50% fuel on hand after a transonic dash, presumably to get to or get away from a fighting position.

3. For the F-35B model, the obvious weight constraint beyond those affecting range, acceleration and turning is Vertical Lift Bringback (VLBB) weight. For the F-35C, the Maximum Carrier Landing Weight is a driver as well as whatever weight will be essential to NOT bust the approach speed limitations.

4. One example is a chart online (that is marked US/FOUO, so I won’t post or link to here) shows the F-35C’s Weight Status in 2012 with a 'target' weight well below the key Carrier Landing Weight limit.

The F-35 and the Infamous Transonic Acceleration Change

Part 3 : Updated and Bumped

(Part 1 here: Part 2 here, and 'Bonus' Block 60 Comparison Here)

I'm still working on the F-35A vs Block 60 F-16 comparison, but wanted to add a reference to a comment I made at Breaking Defense in response to one 'Peter Goon': a former FTE (best known as a talking head for Air Power Australia ). I'm repeating it here because for some reason, the graphics accompanying my response did not post, and one is an update of a chart shown already in this series.  Mr Goon dropped a series of snarky comments, any of which can be discarded, but none so readily as this one:

RE: Q: How does an aircraft that takes over 60 seconds to accelerate from 0.8M to 1.2M at 30k ft ISA have "at least" the maneouvrability of a Block 50 F-16C which does this in less than 30 seconds, with 4 missiles on board?

My response reads thusly:

Well Skippy, your first big problem is that the only F-16C Block 50 that can go from M.8 to M1.2 in "30 seconds" can only carry two missiles and....its about out of fuel.

Your second big problem is that you are comparing your infeasible F-16 loadout with an F-35 KPP configuration that is carrying 60% (of a much larger capacity than the F-16) fuel load AND 2 tons of bombs.

To answer your question more fully, and as a object lesson to others that it is YOU who are really pedaling the "indifference to reality" with hyperbolic nonsense, the F-35A at KPP weights and loadouts SPANKS the Block 50 F-16 in transonic acceleration for all but at the very lightest weight/drag combinations identified in the F-16's operating manual.

I dropped two graphics with data extracted from the Hellenic AF Block 50/52 Change 8 Operators manual, but they didn't 'take' for some reason. First, the F-16 Block 50 basic weight/drag data:

This is the heaviest a Block 50 F-16 can get without adding drag by hanging stuff off the outside 

...and then an updated table (data and comment added for clarity only: no existing data changed) of the Block 50's transonic acceleration times:

Only at the lowest weight/drag combinations can a Block 50 transonic performance best the F-35A KPP configuration. Remember the F-35A is carrying 60% internal fuel AND two 2K Lb JDAMs. 

Conclusion?

YES, the F-35A has:

  "at least" the maneouvrability of a Block 50 F-16C. 

Deal with it.

Original Post, as posted on 1 March below this point...... 

KPP Requirement or no, ‘What If’ the F-35 will someday really need to get rid of all or part of extra seconds in the new KPP enroute to Mach 1.2?

(Part 1 here: Part 2 here, and 'Bonus' Block 60 Comparison Here)

The F-35 Transonic Acceleration KPPs were ‘changed’. This change was almost immediately decried far and wide as a failure by the ill-informed and self-serving critics. I’m certain some have forgotten or missed the discussion in Part 1 where I referenced the DoD documentation describing the process by which KPPs are established, and changes are made, and that they are only changed if the changes are validated as being operationally acceptable. I’m certain others will miss the references in Part 2 where it was highlighted that they changes were always going to happen, if only because you cannot violate the laws of physics. (Those people may be sputtering at their computer screen soon if they aren't already). That the F-35 KPP changes were implemented at all proves the changes were acceptable by those responsible for the integrity of the requirements and supporting system engineering process.

This post and series is not for those people.

It has been for people who want to understand more about the changes and their ramifications. Agreement or approval by me or anyone else as to the acceptability of these KPP changes is irrelevant. The agencies to which they are relevant have already decided.(Right about here those ‘other people’ would mentally register a need to utter a Circumstantial Ad Hominem against those responsible that when you strip away all the unsupported assertions, logically translates into little more than “those people are the experts, what do they know?...oh and “they must be lying!” or “what are they hiding?”)

BUT!... probably, someday, someone flying one of the F-35 variants is going to REALLY need to accelerate M.8 to M1.2 as quick as the original KPP specified or even more quickly (just not often enough to pursue it as a KPP). Truth be told, there’s probably going to be a time or twelve where somebody is going to wish ‘instantaneous’ translation to Mach 10, but you have to draw the line someplace within the laws of physics.

IF there is some operational need to shave all or part of 8 seconds (or the longer times for the other variants) going from .8M to 1.2M, can it be accomplished? If so, HOW would it be done, and is the remedy needed so onerous that it will adversely impact the F-35’s viability or operational utility? With the F-35A needing only to overcome 8 seconds, the program office could have easily just specified a lower weight to accomplish the feat, and a checklist item added to the effect of “if you want to do ‘this’, then ensure fuel and weapons on board do not exceed X lbs”. But as fuel on board at a mid-mission point tends to be a valuable commodity, and weapons carriage is a fighter aircraft’s reason for being, I presume everyone can see why the users, JROC and program office didn’t take that route.

“One Weird Trick”

If, by chance, “8 seconds” is a big deal, even for an aircraft with a ‘greater initial acceleration than an F-16’ and it still means those 8 seconds crossed some breakpoint minimum needed operationally, then the good news is it is rather easy to accommodate. In fact, fighter pilots have been using ‘this one weird trick’ (Man, I hate those ads) for decades to squeeze extra acceleration out of the transonic region.

It’s called ‘Unloading’

Hat tip to Pat ‘Gums’ McAdoo, USAF Lt Col (Ret), at F-16.net for first reminding me of this ‘way back when’:

“RE: transonic accel....... I'll bet that the profile was st-and-level and then gofor it. We who have done it know that all ya gotta do is reduce AoA by lowering the nose a tiny amount and shazaam!”

You can also bet any future opponent that the F-35 runs into WILL also be doing the same thing. Sometimes ‘unloading’ will be the best thing for a pilot to employ, sometimes something else will be the best thing to do. Aeronautics has advanced to exploit the medium to its maximum. There is no magic airplane that does everything better than any other airplane within each generation or two: there's always a 'catch'.

Unloading the wing during an acceleration run through the transonic region pays off in increased acceleration (or reduces the decline of acceleration if that is all that is desired) immediately. It is also the key part of employing the Rutowski Profile (Ref #10 in Part 2) in reducing climb times for the same reasons. When a pilot completely 'unloads' the wing, all of the wing wave drag coefficient contribuion due to lift goes to zero, and the aircraft ‘sinks’ (altitude decreases). This is a relatively slower rate of descent compared to an actual ‘dive’, by the way. But a dive is also an option for even greater acceleration, and as Shaw observes (Fighter Combat, p. 407) it is even more effective the heavier and ‘cleaner’ an aircraft is-- assuming the dive does not take the aircraft past its structural limits. When that much wave drag suddenly disappears, the acceleration rate increases dramatically (Shaw recommends a “sharp pull-down” to a dive attitude then an ‘unload’ as particularly effective). Higher acceleration rates are like compound interest: the more you have earlier, the more the distance you cover and the more speed you have at the end: If the wing is unloaded early in a run when acceleration rate is already high but late enough that the aircraft is near Critical Mach, the time the plane would need to be unloaded might be exceedingly small for an F-35A to achieve 1.2M those eight seconds faster. It might help people to be able to visualize how little difference there is between M.8 and M1.2 at 30K feet if we use a graphic (we're keeping the numbering of figures as beginning in Part 1):

Figure 20: Every tenth of a Mach is about 40KIAS at 30K ft Altitude

An eight second difference for the F-35A in all probability translated into achieving something like Mach 1,1-Mach 1.18 in the original 55 seconds. That's small potatoes as far as overall speed goes. 

Here’s the example of a straight wing drag profile shown earlier:

Figure 21: Typical Drag Curve for a 'Loaded' Straight Wing 

Now, here’s a representation of what the ‘straight wing’ drag curve looks like if unloading the wing reduces the wing wave contribution by a conservative 40%:

Figure 22: Typical Drag Curve for an 'Unloaded' Straight Wing 

The total peak drag coefficient in this instance is reduced by 25%. Observe in the next figure that the peak drag coefficient ‘unloaded’ at around M1.1 is about the same as just before Mach 1 ‘loaded’, and that even in the typical Critical Mach range for fighter aircraft between M.8 to M.9 (Shaw, “Fighter Combat”, Pg. 399) the drag coefficient is reduced. 

Figure 23: Straight Wing Drag, Loaded vs Unloaded

IMHO, the F-35 Critical Mach Speed, like most advanced fighters, should be well into the upper half of that range IF the performance measures in the Bowman paper are to be believed (We’ll get to that in a moment). 

The actual amount of drag reduction will vary depending upon the total aircraft design (and remember it will also vary by airspeed and altitude). Shaw’s “Fighter Combat” provides a convenient graph highlighting the increases in acceleration that can be expected at different altitudes over a wide speed range for legacy aircraft. It is modified here to illustrate the altitude and Mach range of interest:

Figure 24: Typical Benefits of Unloading on Acceleration (Original source as noted, modified by Elements of Power)

We see in Shaw’s chart that for legacy fighter designs flying from .8 Mach to Mach 1.2, unloading increases the acceleration rates between ~17% at M1.0 to as much as ~20% at Mach 1.2 and ~25% at .8 Mach at the 30K ft KPP altitude (Ref #9). This appears consistent with what we would expect from the differences in the drag curves shown in our examples. It should also be readily apparent that both the F-35B and F-35C could employ the ‘unload’ technique in the same manner as the F-35A. Obviously, the F-35B would only need a small ‘bump’ compared to the F-35C. The smaller the time/speed difference needing to be closed, the more flexibility on timing and duration is available for the pilot to choose when and how long to ‘unload’.

Figure 25: Unloading and/or Diving to Achieve Original KPP times.

The F-35C’s obviously much greater wave drag due to lift than the other two variants (expanded upon in Part 2) also means it would just as obviously benefit MOST OF ALL from the unloading technique. If a dive would be necessary for the F-35C (as the ‘worst case’) to meet the old transonic acceleration standard, it could be able to carry that acceleration beyond 1.2 to perhaps even M1.6  (F-35 Max Speed in level flight. We do not know what the 'never exceed' speed is, so we’ll stick with what we know the F-35C can do. If ending the acceleration run at the same altitude (30K feet in the KPP) is important, the F-35 pilot can accelerate beyond M1.2 and so after climbing at the end of the run, trading smash for altitude, the plane is still flying M1.2 or better.

This might be a good time to interject the observation that if there was ever evidence the original KPPs were established before the aircraft design was even undertaken, it is the original common KPP of 65 seconds for the F-35B and F-35C: two airplanes with vastly different weights and wing areas. This tells me the trade space for the F-35C design might not have been fully understood when the Navy laid down the requirements or the KPP really was a 'let's see what we can get' figure.
We should also note here that the KPPs were/are against a predicted weight standard and that all indicators are that the predicted weights are being beaten, with all variants coming in (for now) below the modeled weights used for the KPPs.  Those lower weights mean lower wave drag to begin with, and in turn better transonic acceleration.   

Shaw asserts that unloading for best transonic acceleration is done close to ‘Critical Mach’. Bowman (Part 2 Ref #9) identifies the F-35A KPP threshold for max speed at 30K ft altitude without afterburner at >.96 Mach. This speed cannot be too far above or below F-35A Critical Mach because “at speeds faster than the Critical Mach number the drag coefficient increases suddenly, causing dramatically increased drag”. Afterburners (and/or unloading) would soon be required to go any faster once Critical Mach is reached.
Bowman BTW, is now a Navy Captain, and as far as I know continues to NOT be an F-35 'fan'. I'm still hoping for some karma backlash that will tie him to the F-35 program as a developer or operator, just for the entertainment value alone.   

Conclusions?

Other than changing the KPPS evidently was not a 'big deal', there's not much to conclude: just a lot of open questions remain.
That the program was warning far ahead of the KPP change that the spec was unrealistic (Ref #3 and #4 in Part 2), makes the initial acceleration KPP looks more like it was a ‘show us what you can do and we’ll revisit the issue later’ placeholder. An entirely likely possibility is that as the program matured, different advantages were seen in areas of aircraft capabilities that shifted design emphasis to 'someplace else'. A KPP may be set based upon an assumption of X capability would require KPP X to be one thing, and then as the design matures, and operational concepts evolve or even threat perceptions shift, it becomes apparent that X capability isn't as important as Y capability, which if is addressed would require more or less out of the KPP X.  

Examples? Program news over the years seemed to talk a lot about range and carrier approach handling as being 'big deals'. Did range become more important than acceleration? If so, fuel could have been added which increased weight and that reduced acceleration. For the C model, did the Navy decide a bigger, higher drag wing meant fewer carrier landing mishaps? It is also entirely possible one or more of the variant KPPs started simply as a wish-list item.

We've heard before about he F-35 KPPs being based upon aerodynamically 'clean'  legacy aircraft specs. Was that a 'miss' where the initial KPP-setters failed to recognize the physics involved, or they did recognize it but since there was no design to evaluate at the time, they let it go: leaving it as an admirable goal but also knowing the KPP could always be changed later? That last explanation makes most sense to me. I've dealt with the acquisition system bureaucracies for decades, and that kind of development  seems totally in character for how the system works. But whatever the reason, we can only 'guess'. We don’t really know 'why', and I wouldn't be surprised if no one is still around within the program who remembers the 'why'. It would make a terrific question for some politico to enquire about, especially if there was some dark secret behind the change as F-35 detractors seem to often insinuate.  

The Bottom Line, Again

For the F-35A model, the 8 second difference between new and old KPP appears to be trivial. The F-35B would probably have to unload a few seconds earlier or for a few seconds longer to meet the old KPP and the F-35C may have to unload a lot earlier and for a few more seconds to do the same.

But it is hard to say for certain, because the B and C early acceleration profiles may be just as good as pilots flying the F-35A assert about the CTOL version. The F-35C might have the toughest time making up the acceleration difference because it has a much larger non-lift contributor to wing wave drag to go with the larger lift contribution. But as it is also slightly longer overall and especially longer in the wing and tail surface areas, the F-35C shape in its entirety may (I don't think so but I can't rule it out) be lower drag than the others above Mach 1.1+. Or the F-35C may have other lower drag advantages due to something like its ‘cleaner’ wing attachment transition on the bottom surface. Who knows?

The newer 'changed' KPPs are as far as we know, still based upon modeled F-35 performance using “end-of-life, worst-case” scenario relative to the F135 engine’s power capacity” (Ref #7 Part 2) and “two per cent thrust” penalty (Ref #8 in Part 2). These ‘wedges’ against the F-35's performance could also be the difference between meeting the old KPP and needing the new KPP in the case of the F-35A, and part of the difference for the F-35B and C. 

The changes might also (almost certainly for the F-35C) have been due to encountering an ever-so-slightly higher than planned/predicted peak transonic drag coefficient, or some combination of the above. Contrary to what some might think, computational fluid dynamics and wind-tunnel testing do not prevent small surprises when the aircraft finally flies, they just lower the chances and severity. Sometimes those surprises go undiscovered for years (Bitburg Roll anyone?), and frankly I'm STILL surprised at how little difficulty the F-35 has had in some performance areas compared to legacy aircraft.  Beginning at about .8 Mach, even the tiniest drag [design] differences affect an aircraft’s [drag] performance out of proportion to the differences. The ability to cruise in military power at Mach 1.2 for some distance (Part 2, Ref#2) indicates that for the A and the B model at least, that ‘peak’ in the Drag Coefficient around Mach 1.1 is a fairly narrow one. 

The importance of the KPP change all comes back to what Tom Burbage was quoted as saying in Ref #4:

“...the biggest question is: are the acceleration characteristics of the airplane operationally suitable?”

The people buying and flying the airplane apparently say ‘yes’. And they've got the data and required knowledge and judgement to make the call. The voices outside the program do not.

Acceleration Sidebar: Is Acceleration More Important to Offensive or Defensive capabilities?

If I had to make a guess as to whether or not F-35 transonic acceleration was more critical in the A2A arena for closing on an enemy or escaping an enemy, I would say it is more important as an offensive attribute for closing on an enemy. Why? For two main reasons. First, I seriously doubt there is a fighter in existence or on the drawing board that can be expected to consistently attempt to overtake an F-35 without hesitation: or any aircraft that will competently shoot missiles over the shoulder at their pursuers. Second. The F-35 is being fielded as an optimal pack hunter: any aircraft pursuing one F-35 will always be a little more cautious if the pilot has reason to expect there to be another F-35 or two that he has no clue as to where it or they are.

Next Up: 

Stimulated by Commenter 'Tim A.' in Part 2, I'm going to do a quick parametric examination  of transonic acceleration differences between the 'ultimate' F-16 (Block 60) and the F-35A at A2G and A2A weights and loadouts. Nothing too extensive-- just something to ponder.

  

The Air Force Reaffirmed "A-10 retirement decision" in a "Week"

Anyone with reasonable exposure to the 'issue' could have done the same thing. 

If I thought anyone was interested, I could lead a little online systems engineering exercise. Except we'd have to endure the "Because Big Gun!" argumentation. You already know where I stand on that 'point'.

And Ohohohohohohoho the A-10 fanboys of the U.S. Nostalgia Force are going to go ape-you-know-what over this one.

After a week of concentrated study of its close air support (CAS) role, the US Air Force essentially has decided to stick with plans to gradually retire the Fairchild Republic A-10 Thunderbolt II and hand the CAS mission to the Lockheed Martin F-35.

It really just took a week to run everyone involved at the top through the relevant information already in hand.

The CAS "controversy" has been studied to freakin' death leading up to this moment, and it's not exactly like ANYONE who has paid attention doesn't already know the USAF has been looking at A-10 obsolescence growing......... like, forever. 

The article at FlightGlobal lays out pretty much what one would expect.

1. Phase out A-10 and phase in F-35 (as planned all along) 

2. Look at alternatives to fill any gaps during the transition (as F-35 capabilities mature). 

That's not 'too complicated' is it? 

Some good details at the link, such as still having dedicated CAS units (Which I note did no good to appease the 'A-10 forever!' crowd the first, last, any time.

If I were to open a group SE exercise to derive requirements for a CAS aircraft, I would start by asking "What capabilities are necessary in a CAS plane?

After the dumb*sses with the 'big gun!' ,'fly slow!', derived qualities spouted off, and if we even cared, we would probably employ the 'Five Whys' approach to backing out the top-level requirements. Example: Why do we need a big gun?, and then based upon the answer, ask why that answer was valid, and etc back to the truly top-level requirements. In doing so, we would arrive at a list of characteristics: effective targeting, responsiveness, lethality, survivability, persistence, etc.

F-35 optimal attack profile with GAU-22 vs. 

A-10 Optimal Attack Profile. F-35 rounds per

square meter density is approximately double 

A-10's even at a much longer, safer range.    

There would be multiple paths that could be followed to meet a desired top-level requirement: a 'Big Gun with lots of ammo' is but one technical solution to 'lethality'.  But we also have 'effective targeting' which does not just support overall lethality objectives -- it also includes "safe to employ" as one of many sub-elements of "effectiveness". So once we got into looking at the optional material solutions we could select for 'lethality' we would then perform tradeoffs among the many desired attributes, and many of them will be contrary to each other. A balance among all of the attributes would have to be achieved. 

Done to Death

But we don't have to do this study. It's been done to death. And it wouldn't have to have been done very well at all to produce an argument that beats PFC Short Stroke's anecdotal recollections of 'that day in the 'Stan', UNLESS we can count on CAS not ever/likely needing a 'better' (as in 'survivable in a medium-high threat arena') weapon system than the A-10. If you can't guarantee a low-threat battlefield future, you have NO basis for preserving an asset that is only survivable in a low-threat environment. That's not the only reason the A-10 needs replacing, but it ought to be the easiest one to grasp.