hopsalotActually I looked up quite a few articles before I posted previously on your wing sweep chart. I make an effort to provide links for facts and express opinion as just that, an opinion. What I stated before still holds true: your assertion –“that As we can see, all fighters has a wingsweep of 40* or more…but wait, there is an abomination, we find that one has a wingsweep closer to 30, 33 to be precise.”, is a gross generalization. I’ve attempted to show that logic is simplistic, I wonder if you actually read your NASA link as it points out the relative disadvantages for wing sweep. Obviously, if you were designing a fighter that had a requirement for uncompromising mach 2 performance, you would choose a highly swept wing. The F-35 is a multi-mission aircraft and has a low aspect wing. Like most aircraft there is a compromise between supersonic and subsonic performance.
You have a right to your opinion about the F-35, but blanket statements “like its predecessor F-117, it has the designation F, but it is not a fighter, it is an evolutionary subsonic bomber but with much better self defense aid, even able to go supersonic if given enough time.” are not supported by fact http://techdigest.jhuapl.edu/TD/td1801/steidle.pdf
Another example of a blanket statement- “As i already posted, there are several factors, none of which favor F-35 in the transonic regime”, Again not supportable http://www.airforcemag.com/MagazineArchive/Pages/2012/November%202012/1112fighter.aspx, “There is a major extension of the fighter’s range if speed is kept around Mach .9, O’Bryan went on, but he asserted that F-35 transonic performance is exceptional and goes “through the [Mach 1] number fairly easily.” The transonic area is “where you really operate”. The F-35 was designed with transonic performance in mind.
The issue goes back to the initial RAND study and APA smear campaign. The “Anti” crowd make the same disproved assertions again and again as if repeating things like “The F-35 can’t climb, can’t turn, can’t run” will make their statements true. I am not a unconditional supporter of the program, but there is a difference between fact and opinion. People want to knock the program for being late, over budget, or threatening to domestic defense companies, fine. But claims that the F-35 is not a fighter aircraft because it is not their idea of an air-superiority fighter ala F-15, SU-27 etc, ignores the design goals of the program. It’s a “Strike” fighter and hopefully a good one. Some will continue to claim that a duck isn’t a bird because it doesn’t look like tweety,but it does not make it true
It is much easier throw out baseless smears than it is to refute them with sources. You can dismantle and debunk his entire post line by line, as has already been done in this thread repeatedly, and he will just come back next week and post it again. In a sense it is trolling, and in a sense it is a very real unwillingness to accept facts that are unpalatable to him.
In the end none of it will influence reality one bit. Even someone with zero knowledge of aircraft would need only look at the reception the F-35 has received relative to the various 4th generation fighters to see just how clueless the claims some on this board make are…
If you drew up a list of the 20-30 most technically proficient air forces in the world today, how many of them are buying or planning to buy the F-35? How many of them plan to use the F-35 in an air to air role?
hopsalot” Again, my point never was that “it is useless” or “it isn’t a fighter” – that’s basically populism. But it does have a number of very real weaknesses which certain groups have great trouble acknowledging (which amounts to the same kind of populism).”
Quite, no-one is suggesting that it isn’t a multi-role fighter, just one which is highly specialized towards battlefield interdiction. In the same way that the F16 was designed for the 400nm central european theatre with a dogfighting stance the F35 is designed towards available bases near to potential target countries and the economically most efficient way to bomb them to a pulp. Frankly the loss of range is a far bigger deal than the loss of time to target, sustained g ratings or other ‘sexier’ aspects.
To my mind the easiest comparison is with the A4 skyhawk though with encyclopedic sensors, it was intended as a cheap and relatively stealthy lo to the F22 high. The A4 was certainly nimble, even good enough to give an account of itself should the need arise. The difference is one of doctrine ( which is only barely recognized by the raw data), namely that BVR is indisputably the future and that a medium bomber should be able to turn and face leakers in this regime rather than knife fight them or run.
In this aspect the reliance on frontal LO is both a blessing and a curse. Should the doctrine prove correct and an F35 be capable of defeating a BVR launch due to it’s frontal aspect stealth, and scoring kills via it’s own BVR ability, then the design is sound.
If however the doctrine is flawed ( due to BVR ripple firing of multi aspect AAMS or AIM120’s relative but unproven weakness ) then the F35 is merely headed head first into a knife fight where it is at a serious disadvantage in energy, visibility and weapon load.
I suspect many of the outrageous claims for the F35 would not exist if the design had even come close to achieving it’s target cost. Frankly this was one of the main design parameters ( arguably the most important one ) and the single biggest flaw in the weapons system to date. I’m a big fan within reason and mission, but not a fan boy with regard to it’s less likely usages.
As before, riddled with factual errors…
:stupid:
Do you really think simply restating debunked garbage is somehow productive?
hopsalotAll those words and they still says nothing magical about 40 degrees. Are you here to share info or something else? Please find a technical document that says 40 degrees is magical….maybe I’ll relax that requirement and let you have some caveats to go with it. That will be interesting.
This is nothing but yet another case of certain clueless individuals trying to push an agenda.
It is easy to select a list to make one aircraft stand out and then hop up and down calling it an “abomination.” Oddly enough despite the shallow opinion of some, actual professionals don’t seem to regard the F-35’s layout as any sort of abomination…
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As the saying goes… imitation is the sincerest form of flattery…
hopsalotWell, there aren’t that many possible answers, and not one of them looks particularly plausible. An application of Occam’s Razor is in order, IMHO.
And the F-2/F-16 example is very germane, because inlet limited or not, their top speed is still determined by drag canceling thrust (the latter element is where the limit hits home, but it does so in the same way for both). If the F-2 had significantly more drag, it would tell in a lower top speed.
No, you still don’t get it.
Read this:
An excerpt:
Now for the promised physical limits. Two examples are worthy of discussion. The first involves the calibrated airspeed limit on the F-16. The Dash One sets the knots calibrated airspeed, or KCAS, limit at 800 knots. Interestingly, the airspeed limit is actually based on the engine operation. With the original -200 version of the F100 engine, you almost had to dive into the point to exceed 800 knots. But just such a dive could surpass the physical limits of the engine because the -200 engine control system essentially runs open loop. That is, the control system would allow the compressor discharge pressure to increase beyond the physical limits of the engine. Therefore, the limit was established at 800 knots to ensure that the -200 engine remained within its envelope.
A tragic accident exemplifies the frivolity (read stupidity) of exceeding this limit. One of the pilots in the test squadron at Eglin (someone who certainly should have known better) took it upon himself to see just how fast the F-16 would go. On the way back from a rather mundane test mission, he climbed to 16,000 feet, turned the wick full up, and nosed over into a dive. In reconstructing the flight, we feel that he got well on the high side of 850 knots. Since the compressor discharge pressure was uncontrolled, the pressure became high enough to distort the engine case. The turbine rubbed the engine case at a ferocious rate, went through the turbine tip seals, and began eating into the engine case with equal fury.
…
Somehow our intrepid (but not too forward-thinking) aviator got out of the ruined airplane. But he broke both arms in the process. He ended up drowning in the Gulf of Mexico. A very bad scene from any perspective.
Those of you who may have been getting in the books or listening to the engine awareness briefings of both Pratt & Whitney and General Electric will probably now want to point out that the later -220 and -229 versions of the F100 and all models of the GE F110 engine have positive, closed-loop control systems. I’m glad you’ve been paying attention. The -220 engine has more thrust than the -200, once you get it moving. But it is seldom more than ten percent better. So you’ll still usually have to dive the airplane to exceed 800 knots.
But the -229 and all versions of the F110 have enough power to go right through 800 knots like it isn’t even there, straight and level, sometimes as high as 15,000 feet. So why not exceed the limit?
Pay attention. The newer engines control the compressor discharge pressure for the most part by rolling back fan revolutions per minute, which cascades through the engine and, thus, effectively limits the N2 (the high-pressure compressor) discharge pressure. They are not taking thrust away, but they are preventing thrust from building at the rate it would like to because of the increased ram effects. However, improvements throughout the rest of these engines result in a lot more thrust in this part of the envelope. Furthermore, this extra thrust comes without the risk of hurting the engine. So if the engine is not the limiting factor, what is?
Well, it is not the F-16’s flutter limit, which is theoretically on the plus side of 900 knots. That is an impressive number, n’est-ce pas? Under test conditions, I’ve been as fast as 845 knots with the early GE engine. Further, it was readily apparent that the airplane was nowhere near ready to quit. It is really a ride to feel those levels of acceleration for that length of time and still know in your heart that there is a lot left. We could have easily taken that airplane (one of the old beat-up, full-scale development airplanes, F-16A No. 1) and set a low-altitude speed record with no preparation other than getting the Federation Internationale de Aeronautic to Edwards to certify the timing. But once again the political climate was not right to grant the F-16 any favorable notoriety. Plus, we were told in no uncertain terms that we were not even to talk about such an attempt. Too Bad. It would have been fun to see just how fast we could have gone. It most certainly would have been a big number.
I almost choke, however, when I hear that some pilots have had the airplane as fast as 870 knots. Even considering that the speed may inflate a little every time the story is told, I really don’t like to hear about anyone exceeding 800 knots for no apparent reason.
Why? Anybody have a clue?
The answer concerns the canopy. It has never been qualified at the kind of airloads and temperatures involved with flight in excess of 800 knots. If you don’t think the airspeed effects on the canopy are real, the next time you have the opportunity to fly for any period of time with the clock reading more than 500 knots, take your glove off and feel the inside of the canopy. It gets damned warm. Further, the effects are exponential. And going from 500 to 800 knots is a hell of a lot more than the sixty-percent increase that simple, linear arithmetic would lead you to believe.
Don’t get me wrong. In combat (the operative word), knowing what I know about the F-16 engine combinations available, if I had a MIG-29 just out of range at twelve o’clock (or worse yet, just in range at six o’clock), I wouldn’t hesitate to go over 800 knots. But doing it as a matter of routine in peacetime because it’s fun is plain dangerous. No one really knows just how many pressure and temperature cycles involved with these airspeeds the canopy can take before it starts to get tired. And I can guarantee that you will not want to be the name behind the data point associated with a face full of canopy somewhere in excess of 700 knots just because you and your squadron bubbas have ignored the airspeed limit one time too many. This is a very real physical limit. I strongly encourage you to respect it.
The point we are trying to make to you is that there are things other than drag that can cap performance. Both the F-16 and the F-2 are limited to the same speed not by drag, but by an unwillingness to completely characterize how the canopy can tolerate higher speeds. Such tests could be done and if necessary a stronger/more durable canopy could be developed but as has been said over and over again in this thread, speeds in excess of M2 really weren’t seen as useful enough to justify such an effort.
We don’t know what is limiting the F-35’s speed to M1.6, but it isn’t thrust/drag.
A 450 pound targeting pod isn’t going to make or break things, and as I said fuel isn’t really relevant.
This is simplistic. A targeting pod may won’t make or break things by itself, but it is additional weight and drag. Everything you hang on a 4th generation jet has a significant impact on its performance. Take a look again at the chart again(note that it includes a pod, though not in isolation):
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Non-stealthy aircraft which need external tanks can dump the excess baggage the moment they are challenged to fight, if anything that’s an advantage. If bounced in strike configuration they are not required to maneuver with high internal fuel loads, the F-35 is.
It can be an advantage and it can be a disadvantage, here I would have expected you to take the more Russian/Soviet view that large internal fuel capacity is preferable to relying on external tanks. An aircraft like an Su-27/30/35 bears a penalty for its large internal fuel capacity, but the Soviets concluded that this was nonetheless the best possible solution due to the advantages it conveys, that being the relatively small performance penalty associated with carrying a large fuel load relative to a jet reliant on external tanks.
If a Western fourth generation jet drops its tanks in many cases it is mission killed… and may have excellent performance, but will likely be using it to return home. If an F-16/etc flys out to fairly long range and then drops its tanks, and along with them a significant chunk of its fuel… well it isn’t going to be hanging around long is it? It has to retain enough fuel to return to base after combat. An Su-27/30/35 or for that matter F-22/35 would most likely retain their fuel and the resulting endurance. An F-35 is capable of dumping fuel, but it wouldn’t likely do so. (and the truth of the matter is that even aircraft like the F-15/16/18/Eurofighter/etc typically retain their tanks, even if empty, unless they are really forced to drop them)
Come on, that’s a truism. Of course whether you add X pounds in fuel or X pounds in weapons isn’t going to make a difference in performance (well, other than range, obviously) on an aircraft with internal weapons. CG changes, if any, will be taken care of by the FCS, so that there would be little difference discernible to the pilot between two F-35s of the same total weight but different weapons/fuel ratio is eminently NOT surprising 😉
That is true of an aircraft with internal weapons, but that doesn’t apply to most fighters flying today and so it is noteworthy. Look at the above chart of Super Hornet speed performance and consider that that the F-35 with 6 internal missiles, 18k lbs of fuel, and an IRST/targeting pod is still capable of M1.6. This is not a small distinction.
Again, not being able to jettison the weight and drag associated with the additional fuel can actually be a disadvantage. It’s done for a good cause on the F-35 of course (stealth), but that’s beside the point here.
Not having appreciable extra drag associated with a large fuel load is a big advantage. The disadvantage is greater internal volume and airframe weight. Stealth considerations drove the F-35 to carry its fuel internally, but as I pointed out above the Russians adopted a similar approach for purely performance reasons.
You’re agreeing with me, the above statement basically paraphrases part of what I said – but it also means the F-35 lags the majority of 4.5 generation and 5th generation designs. Or is it that you don’t distinguish between 4th generation and 4.5 generation designs? That’s an entirely new can of worms, of course – it may be better to agree to disagree before we open that one.
Certainly the F-35 is not intended to rival the F-22, PAK FA, or J-20 in aerodynamic performance. I think the jury is still very much out on how it will compare to the J-31. On the whole 4.5 generation front… the Super Hornet falls into that class, as does arguably the F-16 Block 60. What about the J-10 or Gripen? If you use 4.5 generation to mean Eurofighter or Su-35 then you may have a point, but they aren’t the only jets out there.
Good lord, I’m not even saying the F-35 is a poor design, just that it has pros and cons like every other fighter. Seems the idea that it has ANY cons at all doesn’t sit well with some, and particularly so where its air-to-air performance is concerned.
Of course it has pros and cons like any fighter. What I get tired of are the clueless sorts that ignore all evidence and all pilot testimonials to insist some variation of:
“Much like its predecessor F-117, it has the designation F, but it is not a fighter, it is an evolutionary subsonic bomber but with much better self defense aid, even able to go supersonic if given enough time.” (from earlier in this very thread… :very_drunk:)
hopsalotBtw anyone noticed the last post on Rafale, clue it flew as slow as 15 Kts …
Paper presenred at the AGARD FVP Symposium on “Advances in Flight Tesring”,
held in Lisbon, Portugal, 23-26 September 1996, and published in CP-593.Do that in a F35 🙂
:rolleyes:
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hopsalotI see no reason why the F-35 would be limited at Mach 1.6 by anything other than drag.
As already explained, it is a certainty that they are limited by something other than drag in at least the F-35A and F-35B cases. The only question is why.
Heavily? By conventional standards 5000 pounds is pretty modest. And yes, the Flanker does an impressive dance even with weapons, at Farnborough in 1994, in response to criticisms that it would be far less agile with a real world load, Sukhoi promptly had one Flanker with 10+ A/A missiles fly an essentially unrestricted display while another – with an *asymmetrical* load of no less than 5.5 tons (that’s more than 12000 pounds!) of various A/G stores – was nonetheless still capable of incorporating 2 tail slides into its more subdued routine. Judging on that basis, I’d expect a Typhoon or Rafale in 2013 would cope fairly well with 5000 pounds (even relatively speaking that’s a substantially lighter load than 5.5 tons on a Flanker).
It isn’t just the weapons, it is the fuel and a targeting pod as well. I never said that an aircraft couldn’t perform at an air show with a load… only that their performance would be heavily degraded.
How long is a piece of string? ‘Minimal’ is all kinds of subjective – minimal compared to what?
Well, he said so in his quote… in line with an increased fuel load.
I can agree to that (I did say ‘most configurations’), with a caveat – air to ground loads is a bit too broad a statement, isn’t it? As soon as the load is such that even the F-35 has to use external hard points the advantage disappears again.
No, but its advantage is smaller with external loads. The simple fact that it can carry 18k lbs of fuel internally along with its targeting pod and some of its weapons is a huge advantage.
So the F-35 lags most 4.5 generation fighters with light air-to-air loads, exceeds them with light air-to-ground loads (which are of dubious relevance to the fighter role), and suffers the same problems as everyone else once external stores enter the picture.
No, I would say it is in line with most 4th generation fighters when loaded for air to air, lagging only the most capable of those aircraft. (essentially that it is right amongst any of the single engine types as well as aircraft like the F-18 and Super Hornet)
hopsalotIt all depends on how one counts. The marginal cost is probably less than 4000$/hr.
Um, not if fuel costs alone are $5,350 per flight hour… :rolleyes:
Compared to the Super Hornet, the Gripen C (from the Janes study) has roughly 40% of the installed dry thrust –> about 2/5ths fuel consumption. And it requires much less maintenance. Ofc the difference in cost will shrink if you include the facilities and similarily increase if all you include is whats crucial just for operating the ac. Janes say that the Gripen cost is roughly 42% of the FA18EF costs when compared to the FOC Super Hornets i USN.
My my, that sounds awfully familiar doesn’t it? Who explained that to you a few days ago in this same thread?
Which is it? Is it 11,000 per Super Hornet flight hour compared to 4,700 for the Gripen? That number would be in line with the installed thrust of the two… (2 x 13,000)/11,000 = 2.36. 4,700 x 2.36 = 11,092 Those numbers are plausible given that the Gripen’s number clearly counts little more than fuel and other consumables for an hour of flight. So why did Janes include the 24,000 number given it is clearly referring to a more inclusive measure of costs?
While we are at it… given that the Gripen NG will use the F414 with 20% more thrust we can expect its fuel costs to be approximately 20% higher, putting the Gripen NG in the 5,600 range…
I guessed at $5,600… the Swiss expect to pay $5,350ish… not bad. 😎
The Janes study is the only apples to apples comparison out there (except for the relation one gets where they compare Hawk and Gripen or the RTAF numbers).
Nope, as proven by this Swiss data the Janes study is counting essentially nothing but fuel for the Gripen and is trying to quote more all inclusive numbers for many of the other jets. (18,000 for Eurofighter for instance when Janes claims its fuel costs alone are $8,200)
So the comparison shouldnt be treated as gospel, but as an effort to make an apples to apples comparison it is legit.
The comparison is essentially useless as it is yet another non-apples to apples comparison. $5,350 for Gripen NG compared to 11,000 for SH, or $8,200 for Eurofighter is plausible enough, but for some reason Jane’s decided to throw a bunch of other numbers on the chart…
The 4’000$ figure may have originated in the late 90s/early 2000 when SwAF had conscripts doing maintenance. So as a non inflationadjusted figure it is also correct. And untill we know what the numbers actually describes it is neither gospel nor lie.
Oh great… :rolleyes:
That makes perfect sense, lets use fuel prices from back when oil cost $25-35 a barrel. That is perfectly reasonable… :stupid:
http://money.cnn.com/2000/09/11/worldbiz/oil/
hopsalotThe Janes study is legit. For starters, 20% more installed thrust does not mean 20% more fuel burn. In this particular case it’s 16,4% higher fuel consumption, but in reality the interesting part is how much thrust that is used, and that comes from drag and mission profile.
According to the report the difference in cost for the FA18E/F comes from the fact that the USN Super Hornets are at full operational capability with fairly high sortie rates and the australian figure is from before IOC. Most users would likely end up just above the figure for USN (because of sortie rates and fleet size, the higher they are the lower the CPFH gets). The 8’200 figure for the EF2000 is only fuel as is evident if one reads the report… or at least look a the asterisk in the chart.
The fact that it was ordered by SAAB says nothing about there being any bias towards Gripen. The only thing it means is that SAAB knew that their product would win the comparison so they requested an external source to prove it. This is standard practice.
When you sell a product it is always good to have non users proving that your product is better than the competitors no matter what field we are talking about. As for the actual numbers they are not to be taken as gospel. They are benchmark numbers for a standard AF, the only “hard data” is fuel, and that mean they will have to follow slightly altered standard models like this one (used for Eurofighter).
So it’s not just PR. It is a carefully selected comparison with a known result. There is a reason why the Gripen competitors didnt request this.
Just thought it was worth bumping this up…
hopsalotNonetheless, as I stated earlier, it would be not at all unusual for top speed to be essentially unchanged by the kind of differences between the F-35C & -A: the Mitsubishi F-2 is basically a Block 30 F-16 with larger wings, bigger horizontal stabilizers and more weight (sound familiar?), yet (in brochure terms) top speed remained exactly the same.
That is because both the F-2 and the F-16 are limited by their inlets, not drag. This comparison is actually similar to the F-35.
True enough, if you say 5000 pounds that implies an A/G-load out (2x 2000-pound JDAM, 2 AMRAAMs) and when you start hanging big bombs off a 4.5 generation fighter it is not going to supercruise anymore and most likely it will also cease to out-accelerate the F-35. Although if you could mount them in tandem between the engines on the Su-35S it might still monster the F-35 – but there is no shame in being monstered by the Flanker, you’re in good company 😀 Still, this isn’t really the right kind of context for comparing *fighter* performance.
True, with full fuel and 5k lbs of weapons you are not talking about air to air, but I think you are greatly over-estimating most 4th generation fighters. Equipped with a similar air to ground load most would be strictly subsonic with sharply reduced maneuverability.
The F-35 retains the ability to get to M1.6 and maneuver well even while heavily loaded. In this comparison nothing else comes close. (with the possible exception of a very heavy-weight aircraft like an Su-35/PAK FA/Strike Eagle)
A couple other sources on the same topic:
The outstanding handling, acceleration, and the maximum speed of the aircraft is useable in a combat configuration unlike in legacy fighters. Beesley said that recently he flew an F-35 test flight with a full internal load of two 2000 lbs JDAMs, and two AIM-120 missiles. The aircraft “felt like it had a few thousand pounds of extra fuel” but otherwise Beesley said there was practically no degradation in the aircrafts’ performance.
http://www.livescience.com/3032-fighter-jet-controversial-future-fleet.html
(Incidentally this also also scores in the drag column in the drag vs weight discussion. If almost 5k lbs of internal weapons result in only minimal performance degradation in an F-35A, then how much weight would be required to explain the F-35C’s acceleration? )
Air Vice Marshal Osley: 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.
…
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.
(Interesting note, this confirms that the KPP that the F-35A missed by 8 seconds is calculated with an air to ground loadout, which explains a lot of the confusion among some about the seemingly contradictory reports about the F-35’s acceleration performance.)
So bottom line, when it comes to an air to ground load it is no contest at all.
Compare performance with 4x AMRAAM though and most 4.5 generation designs have some way of carrying 4 to 6 MRAAMs on wing-tips or in conformal wells or in inlet tunnels with very little to zero performance degradation and will therefore retain their performance edge.
This is true, but don’t forget that that was true of the comparison on the previous page (between the F-35 and F-18 and Super Hornet) as well because they were loaded with 2 x Sidewinders (wingtip) and 2 x AMRAAM. (should be conformal along the intake) That is an awfully low drag configuration for the Hornets. Clearly a Eurofighter is faster than a Hornet, but then nobody says the Hornet isn’t a fighter…
If military certification is anything like civilian certification there’s nothing significant in the F-35 doing that – ALL fighers will have done so during testing. Airliners are required to demonstrate safe flight at a set percentage above the maximum operating Mach number for which the manufacturer wishes to gain certification (which for the Boeing 747 and a number of business jets meant nudging the sound barrier!).
Oh I am not suggesting that F-35’s will operate in excess of M1.6, only that it is not limited to M1.6 by drag.
hopsalotAbout operational cost of Gripen E, there is an official 2012 estimative from Swiss Defence Department :
Programme d’armement 2012
It is the 1st link (PDF of 52 pages), “Programme d’armement 2012 et loi sur le fonds Gripen”
In page 36 there is a table to operate 22 Gripen E :So :
– the annual operation cost of each Gripen E would be CHF 4.64 mi (US$ 5.20 mi)/year in total, or CHF 0.955 mi (US$ 1.07 mi)/year in fuel, CHF 2.32 mi (US$ 2.60 mi)/year in maintenance, CHF 1.09 mi (US$ 1.22 mi)/year in personnel;
– using a standard calculation with 200 hours per year to obtain the Cost Per Flying Hour (CPFH), we get CHF 4.77 (US$ 5.35) thousand/hour with fuel, CHF 11.6 (US$ 13.0) thousand/hour with maintenance, CHF 5.45 (US$ 6.11) thousand/hour with personnel, giving a subtotal of CHF 16.4 (US$ 18.3) thousand/hour with fuel+maintenance, or total of CHF 21.8 (US$ 24.4) thousand/hour with fuel+maintenance+personnel.
Nice to finally be able to put this to rest with actual data.
It appears the study Saab commissioned from Jane’s did in fact show little more than fuel costs as the Gripen’s “operating costs.” (actually, not even fuel costs according to what the Swiss expect to pay)
hopsalotSure acceleration is affected strongly by drag, but as I said:
1. The effect of weight is still far stronger than it is for top speed, so they will likely be much closer with respect to the latter than the difference in acceleration shortfalls might suggest.
Top speed is fairly insensitive to weight, except to the extent that weight increases drag. We agree there.
What I am saying is that by the time you get to the transonic regime weight is much less important than drag. Meaning a fully fueled(internal) will accelerate similarly to a lightly fueled aircraft. Of course the lighter aircraft will win, but no reasonable weight growth could account for a miss by 40+ seconds.
2. There should be less scope for (dramatic) drag growth over the course of development, so unlike weight gain the drag differences (which, as follows from #1, primarily determine top speed) would already be well accounted for in the acceleration goals set for each individual version. Which in turn means the margin by which the various models have missed their target probably says relatively little about drag.
Also clearly true… drag should not change significantly during development, but nonetheless weight growth does not explain the missed acceleration time by the F-35C. What likely happened is that the KPP were set well before the current configuration was decided on and it was clear from very early in the process that the acceleration target could not be met by the F-35C, which is more or less what this article says:
The F-35′s sustained turn rate requirements have been slashed as have its transonic acceleration requirements. Most impacted is the Navy’s F-35C, which has had more than 43 seconds added to its Mach 0.8 to Mach 1.2 acceleration times. But this wasn’t exactly unexpected, as almost exactly one year ago Lockheed’s Tom Burbage told me this when I was still at Defense News:
“Based on the original spec, all three of the airplanes are challenged by that spec,” said Tom Burbage, Lockheed’s program manager for the F-35. “The cross-sectional area of the airplane with the internal weapons bays is quite a bit bigger than the airplanes we’re replacing.”
The sharp rise in wave drag at speeds between Mach 0.8 and Mach 1.2 is one of the most challenging areas for engineers to conquer. And the F-35′s relatively large cross-sectional area means, that as a simple matter of physics, the jet can’t quite match its predecessors.
“We’re dealing with the laws of physics. You have an airplane that’s a certain size, you have a wing that’s a certain size, you have an engine that’s a certain size, and that basically determines your acceleration characteristics,” Burbage said. “I think the biggest question is: are the acceleration characteristics of the airplane operationally suitable?”
Some of the backstory, according to an industry source is that originally the designers had intended the F-35 to be somewhat longer and more slender–in keeping with the principles of the Whitcomb area rule. Back then, the weapons bays were placed one behind the other–AMRAAMs in one bay, JDAMs in another. Apparently, the tail-end of the jet started to get heavy, and Lockheed had to change the configuration as a result–which is how we got the current weapons bays. They were kinda squished together–to use a technical description. As a result of that design change, there was never any chance that the F-35 was going to be able to match the transonic acceleration of a Block 50 Viper (Lockheed Martin F-16 Fighting Falcon) armed only with two wing-tip AIM-120s.
http://www.flightglobal.com/blogs/the-dewline/2013/01/pentagon-lowers-f-35-performan/
3. On what basis do you assume that the F-35C makes its speed goal, with the F-35A beating Mach 1.6? It seems equally plausible to assume the opposite – that the F-35A meets the requirement cleanly with the F-35C falling short – certainly that appears to be the case with acceleration after all (even though the cause here is probably weight, rather than drag).
The F-35C has already been taken to M1.6:
3 April 2013: F-35C Maximum Mach
Marine Corps Capt. Mike Kingen took an F-35C to Mach 1.6 for the first time during a flight from NAS Patuxent River, Maryland. Mach 1.6 is the top design speed for the F-35C.
http://www.codeonemagazine.com/f35_article.html?item_id=123
Here is another link with a variety of information on the F-35’s speed/maneuverability. As stated previously it is difficult to give a pure apples to apples comparison, but in the real world the F-35 will most certainly offer “fighter” performance.
The F-35’s ability to carry weapons and a large fuel load inside its own skin makes the plane far less draggy on a combat mission than the F-16 or F/A-18, which sling missiles, bombs and fuel tanks below their wings and fuselage, Griffiths said . Moreover, a combat-laden F-16 loses much maneuverability, whereas the F-35 is barely affected by carrying 18,000 pounds of internal fuel and 5,000 of internal weaponry.
“It flies fantastic,” he said.
Griffiths declined to compare the F-35 to the F-16s he once flew. But he noted the F-16 is only technically an 800-knot and Mach 2.02 aircraft. In practical terms, most pilots will never see speeds above 700 knots or Mach 1.6 because real-world load-outs don’t allow it.
The F-35 can’t supercruise like the F-22 Raptor, but the test pilots have found that once they break the sound barrier, supersonic speeds are easy to sustain.
“What we can do in our airplane is get above the Mach with afterburner, and once you get it going … you can definitely pull the throttle back quite a bit and still maintain supersonic, so technically you’re pretty much at very, very min[imum] afterburner while you’re cruising,” Griffiths said. “So it really does have very good acceleration capabilities up in the air.”
Retired Lt. Gen. David Deptula, formerly the Air Force intelligence chief and a veteran F-15 pilot, said having that kind of capability is a huge advantage.
“I’m real happy to hear that in fact is the case, because speed gives you a variety of advantages,” he said. “It allows you to employ your air-to-air missiles from a range much greater than otherwise would be the case.”
Though the F-35’s maximum speed is Mach 1.6, the F-35 test program will eventually push the jet a little beyond that limit to make sure operational pilots have a margin of safety, Griffiths said.
http://www.defensenews.com/article/20110613/DEFFEAT04/106130302/F-35A-Testing-Moves-Into-High-Speeds
hopsalotHow much that tells us rather depends on what those goals were – for example, if the C-model experienced stronger weight growth over the target anticipated when the acceleration criteria were drawn up, it would be no surprise that the effect would be particularly severe – weight has a very direct effect on acceleration (far stronger than on top speed).
As I said, weight has a more dramatic impact on acceleration than top speed, and the scope for weight growth over the course of development is probably greater than for drag growth as well (i.e. most of the drag difference would have been accounted for in the F-35C having a more modest goal).
EDIT: Found some 2002 weight figures and the F-35C has indeed gained noticeably more (16%) compared to the F-35A (10%), so that lends some credence to that theory.
Weight growth wouldn’t explain the difference in acceleration times between the F-35A and F-35C. Certainly the extra weight wouldn’t help, but transonic acceleration performance is dominated by thrust/drag, not thrust/weight.
hopsalotSomeone needs to tell those idiots at RAND that their A2A assessment of the F35 is wrong.. ( Can’t climb, can’t turn, cant run / double inferior).
I do however think they were a bit harsh to suggest that F35s would be clubbed like baby seals.
This again?
Andrew Hoehn, Director of RAND Project Air Force, made the following statement today:
“Recently, articles have appeared in the Australian press with assertions regarding a war game in which analysts from the RAND Corporation were involved. Those reports are not accurate. RAND did not present any analysis at the war game relating to the performance of the F-35 Joint Strike Fighter, nor did the game attempt detailed adjudication of air-to-air combat. Neither the game nor the assessments by RAND in support of the game undertook any comparison of the fighting qualities of particular fighter aircraft.”
Infamous JSF report precedes “abrupt departure” for RAND analyst
The author of a leaked Rand report concluding in a non-peer-reviewed section that the F-35 “can’t turn, can’t climb, can’t run” has apparently left the think-tank.
http://www.flightglobal.com/blogs/the-dewline/2008/10/infamous-jsf-report-precedes-a/
Bottom line, RAND seems to take their reputation seriously. If you make them look like fools they will take appropriate action to set the record straight and guard against future damage.
hopsalotThe Typhoon is definitely inlet limited, but at Mach 1.6 neither a fixed intake nor current composites should present a problem.
Certainly a fixed inlet/DSI could be designed to go faster than M1.6, same for the composites, etc, but something is capping the F-35’s speed and it isn’t drag. (at all altitudes)
As for the F-35C, all it adds is some weight and more wing area (which should actually serve to cancel out some of the weight penalty) – it will have more drag and therefore be slower, but not massively so.
Well the F-35A, B, and C missed their acceleration goals by 8, 16, and 43 seconds. I think that proves that the difference in drag between the A and B is fairly minor, but that the C is substantially draggier than either of the former two.
It’s probably close enough that Mach 1.6 serves well as a ballpark figure for all three versions (say 1.56 for the C-model and 1.64 for the A; you get the picture) – think F-16C & Mitsubishi F-2A, which is a similar situation.
I don’t see any reason to doubt that the F-35C can reach its stated top speed of M1.6, and I suspect that even at that speed the limit is imposed by something other than drag. The F-35A should be able to handily out-perform the F-35C, but I won’t waste anyone’s time guessing what speed it would be limited to if thrust/drag were the only concern. I will say that I think M1.64 sounds awfully conservative given the difference in the acceleration times.
hopsalotOr, for that matter, how it is that the F-35 manages only Mach 1.6 in full reheat when it supposedly can hit Mach 1.2 in dry, despite having a lower dry thrust to afterburning thrust ratio than the EJ200 (due to BPR again). That’s the kind of stuff I mean when I say it doesn’t add up.
I don’t have a great deal of time at the moment, but I will remind you that the M1.6 is not drag limited. (inlet? Structure? Heat?) The point is it is clear that if the F-35C can hit M1.6 with the same engine as the F-35A… then the F-35A could go a good deal faster if something else were not stopping it at M1.6. (for that matter we don’t know how fast the F-35C could go… clearly it is the slowest of the three, but I find the odds that it would coincidentally top out right at M1.6 where the other two are limited hard to believe.)
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