First up lets get the definition of super cruise. From Wikipedia...
Supercruise is sustained supersonic flight of an aircraft with a useful cargo, passenger, or weapons load performed efficiently and without the use of afterburners ("reheat").Wiki goes on to state that the Gripen, Typhoon, F-22 and Rafale are all capable of super cruising.
I find that to be questionable.
I find claims that the Gripen can super cruise laughable.
But more than anything else I question the utility of being able to super cruise.
1. Will it increase range?
2. Does it add anything to the aerial fight?
If the answer to those two basic questions is no ---and I have yet to hear any advantages found in this capability, then the question remains...is it militarily useful or is it the latest buzz?
Oh and before you make the leap that the F-35 is incapable of super cruising, I wouldn't be so quick. Its optimized to perform high subsonic flight but we just don't know yet (and yes I know Burbage has stated that it doesn't but again, we'll have to wait and see).
Your thoughts.
NOTE*
I'm getting rolled in the discussion here. If there is an Engine guy around that can clarify a few issues I'd sure appreciate it. Any bored Aerodynamicists that want to answer a rookies questions would be appreciated too.
Hey Sol,
ReplyDelete1- Yes.
2- Yes.
And for the same reason.
Supercruise means you can sustain supersonic flight without consuming quite such massive quantities of fuel. The engine itself,being much more efficient in supercruise than while using the afterburner, is better able supersonic flight. So you can fight for longer, going faster and (for the same amount of fuel) go farther.
Faster into the fight, faster out. Sometimes it's the difference.
True, if you have a modern, fast, all-aspect AAM(AIM-9X, Python IV/V, etc)...there's little hope at short to medium ranges. But if you're trying to intercept enemy forces, it can let you do more with less consumption...so in our time of precision munitions (ie, one target-one bomb), a plane with leftover bombs and 20 more minutes of fuel at the target area can strike 2-3 more targets on a raging front. That can save you several planes' worth of sorties.
i wonder. the Rafale, Gripen and Typhoon all use legacy engines.
ReplyDeleteno design attempts to make them super cruise...just the stated ability to do so.
as far as range, you're still talking (in the case of the F-22) about a 410nm limit without fuel tanks. even with supercruise you might get to your patrol area faster but what good is that????
to be quite honest the only real use i can see for supercruise is in a platform like the B-1...it can get to a distant location faster to assist troops on the ground...in aerial combat i still don't see nor will i grant the point that its useful...especially in an airplane that is not stealthy.
Sol,
ReplyDeleteBTW. Always a pleasure to read your posts and to see these points being discussed...even if I hold different opinions on some matters.
ditto CBD.
ReplyDeletei don't have to agree to love the debate.
Solomon,
ReplyDeleteWould guess that one reason the F-35 may not supercruise is its typical mission altitude is much lower than the F-22...air is more dense lower.
That lower altitude is one reason why the F-35 is better at air-to-ground. The helmet mounted display and EO/IR capability probably don't hurt in that respect, either.
Cole,
ReplyDeletei wonder about that too. its listed service ceiling is classified but from what i've read its around 60k...the F-22's is listed at 65K....
now typical operating altitude is suppose to be lower but in an air to air scenario there is no reason why it can't get high too...
also i keep hearing that the USAF has altitude limits on its pilots unless they're in pressure suits. i'm sure the F-22 is banging on that pretty hard....
lastly, alot of the negatives regarding the F-35 were to keep the 22 line open....the truth might start to come out pretty soon.
I think that Typhoon and perhaps Gripen NG (which hasn't flown yet but uses a fairly modern American engine and a very small airframe) can use supercruise to an extent, but not as much as F22. I'm not sure what you mean about them using legacy engines, care to explain?
ReplyDeleteLockmart tried to say that supercruise meant you had to be sustaining flight at above Mach 1.5 without burners, which only the F22 can do. Most other sources say that it only has to be above Mach 1. I think Typhoon can do it to Mach 1.2. Whether it can do that with anything more than a 2 AAM load out I don't know.
I think it is actually more useful for a non-stealthy aircraft like Typhoon to have compared to F22 in certain circumstances. If for example the Typhoon was nearing the edge of it's combat radius and was closing with the enemy it'd be able to close as quickly as it needs to get within visual range and can engage easily using it's advantages in manouverability without wasting too much fuel with afterburners. This would be key if the enemy was stealthier or better at BVR ranges for some reason (although I doubt anything except the F22 and F35 currently qualifies there). F22 on the other hand would prefer to sit beyond visual range where almost nothing could touch it, thanks to it's stealth, sensor suite and BVR missiles. Just a thought anyway.
what i mean is that the Gripen uses a F414. not exactly designed for supercruise.
ReplyDeletealso what has me doubtful about the Gripen is that its latest model is larger and heavier. thrust to weight just isn't adding up. to be honest, i'm wondering why the F/A-18E/F isn't claiming the same supercruise capability (i mean you can put missiles on its fuselage and call it a day.
as far as its utility in combat, once detected does it matter if you're supercruising or not? i mean i'm a layman but won't both attacking and defending aircraft be closing as fast as possible one might have afterburner on and other one might be supercruising but its still fight is on and you want energy for your missile shot.
I admit I haven't looked in detail at the Gripen's ability so I don't know for sure if it can.
ReplyDeleteI agree about the combat, the use of supercruise would come if you're attempting to engage right at edge of your range, where every drop of fuel counts and having supercruise could be the difference between having enough fuel to engage and return home or having to turn tail and run. Not a situation that is likely to happen often though admittedly.
Super-cruise is certainly more efficient than afterburner and says something about the overall performance of the aircraft, but is really not an efficient way to travel. Not only that, but while super-cruising the engines and skin of a plane radiate a LOT of heat.
ReplyDeleteThis means that although the airframe may be designed with low-observability (stealth) as a primary focus, while super-cruising a modern IRST sensor can easily detect it from a substantial distance.
Anonymous.
ReplyDeletegreat point about an airplane radiating heat when it goes to super cruise!
modern day IRST are stating to become standard kit. which brings me back to the utility of super cruising.
i go to the Air Force Staff College website on a weekly basis to see if some bright young airman has come up with a way to use this capability in combat.
so far.
zilch, nada, nothing.
that's why i question its actual use...i'm to the point of believing its a brochure item and nothing else.
Hello Sol,
ReplyDeleteAt Farnborough Saab publicly stated (and the Swedish government confirmed) that the Gripen NG with the new iteration of the F414 (thats going in the international Super Hornet soon) has proved a sustained supercruise ability at Mach 1.2 with air-to-air weaponry on board.
The Typhoon has supercruise up to Mach 1.15 with weapons, Mach 1.2 clean, its main hindrance to supercruise is not its engines which are highly advanced but its pitch unstable design which means it flies nose up in level flight, hence aerodynamically useless. The EJ2000 is a very high tech engine, and is more than capable of withstanding supercruise.
The Rafael has stated supercruise ability but has been widely doubted and never proven. Out of the ones listed as 4th or 4.5 gen, the Rafael is the most unlikely to be capable as it has known issues with its engines and power to weight ratio.
The Super Hornet has a similar aerodynamic issue to the Typhoon, plus its straight wing (designed for high wing load required for carrier landings ) and non-composite structure, wont stand up to sustained supercruise without significant structural fatigue. I don't think Boeing has ever envisioned supercruise certification on the Super Hornet, but with the new engines coming online and significant changes announced at Farnborough going forward, standby on supercruise ability being integrated.
The F-35 suffers from a power to weight ratio deficit and a useless boxy design which makes it very difficult to punch through. The single engine (despite being powerful) is not really enough, especially considering that the Super Hornet, which is about the same size and weight, has two engines. The F135 also suffers from a glaring design fault where P&W have wringed extra thrust out of the F120 core by basically making it run hotter and faster without significant change. Result, mechanical fatigue quickly adds up thus ruling out sustained supersonic application. The marketing spin on this is that since the F-35 is designed to operate in conjunction with F-22's they don't need supercruise as the inbuilt stealth is enough to fool air defenses. The F-35 is not expected to take part in air to air combat so those features have been sacrificed or compromised. Its a good plane for the ground attack role, more in the realm of F-117 than the F-15E.
Ron,
ReplyDeleteyou had me bobbing my head like a dope smoker at a Grateful Dead concert right up to the point of your critique of the F-35!
my feelings are well known on the subject so i'll agree to disagree in that regard.
one point though.
you talk about power to weight ratio with the F-35.
its better than the F-18's! well at least at 50% internal fuel....which is the mode that we'd be talking about here.
another issue that i wonder is being taken into consideration when you're talking about supercruising with these other airplanes is fuel.
to get the same fuel carried in the 4th gen's that we've been talking about, you'd have to hang bags of gas off the wings...if you don't then we're back to talking about the F-35 with say 1/3rd of its normal fuel load???
in that configuration you're talking about dazzling performance.
apples to apples isn't easy when you're talking about an airplane like the F-35 and comparing it to what has come before.
Hello again Sol,
ReplyDeleteDont get me wrong, I love the F-35 too, but that doesnt mean its exempt from criticism. There is a lot of wasted potential in the design that has been compromised to save costs (irony yes).
Your point on fuel is well taken, the F-35 being designed for clean configuration stealth has more in-built fuel capacity yes. The problem for them is again stemming from the engine. The massive power the F-135 generates comes at an obvious price, disastrous SFC (similar problem to the F-119) hence the need to carry so much internal fuel, especially given the F-35's stated mission profiles. The reason planes like the F-18, Eurofighter etc have more emphasis on external fuel is simple, their designed mission profiles are much different. The Eurofighter especially is designed for short range fast interception, homeland defence in Europe. Range is not an issue, response time is. The ground attack capability is pretty much an afterthought on the Eurofighter (hence all the problems they are having integrating systems) so the external tanks for strike missions becomes a necessity.
As for the F-35's power to weight ratio, yes its higher than the F-18, but the F-18 also has a lower drag co-efficent. The F-35's boxy design means that thrust has to be that much higher to punch through the sound barrier. Its not impossible to supercruise, just bit harder thats all, and the mission profile doesn't really call for it anyway so why bother.
The main advantage of supercruise is in Cold War style interception missions. The reason that Air Force Academy guys can't come up for a use for it is mainly that the particular missions that aircraft like the F-22 and Eurofighter were custom made for don't really exist anymore. Supercruise guarantees that you get to the target quicker and with enough fuel left for a dogfight. But you are essentially correct when you call it a marketing ploy, at this point in time, supercruise is simply useless.
Ron,
ReplyDeletelove the debate and the education. if we were talking about the proper employment of a Marine Corps squad, platoon or company then hey....i'd be working with a MUCH bigger knowledge base...so since you're talking to a rookie, bear with me.
explain this to me. i keep hearing you say, boxy airframe and that its harder for it to punch through.
by my eyes, the airplane is anything but boxy, it almost looks to get lift from its body...a lifting body if you will. i just don't see the aerodynamic penalty that you're talking about.
with that being said, it goes back to your engine issues and i just don't know enough. trust me, i'll get a basic knowledge because this is bothering me.
so until an exhaustive Google search, this conversation will be paused until i get up to speed on that issue.
but i have to call WTF on the SFC issue even with my limited knowledge.
the F-35 has or will have the ability to loiter over the battlefield for a long time. its agility will match the F-16, its speed will also equal the F-16's but more to the point its payload is internal which grants it the ability to be more aerodynamic than the legacy planes with fuel and bombs hanging externally.
additionally even the Stealth Eagle and future F-18 are developing pods to carry weapons internally.
its just not adding up.
more research on my part is necessary.
cheer sol, love a good debate now and then to keep me honest.
ReplyDeletejust one point, lift, especially fuselage created lift (and yes the F-35 is designed with body lift in mind out of necessity) has very little to do with drag. The problem that the F-35 and to a certain extent the F-22 both face is that stealthy angular body panels may deflect radar but do not provide the aerodynamic efficiency of a smooth panel. Basic aerodynamics states that smooth, curved surfaces are most efficient, but stealth requires the exact opposite. The F-35's front profile is a pointy brick. Its a unique and so far unsolvable conundrum.
As for loiter, thats a very very subjective matter. Combat capability is too far down the pipeline to be debating right now. The SFC numbers are simply the raw data that P&W have on testing so far. The F-135 has no specific technologies built in to increase fuel economy, its a basic F-119 core running at a higher temperature and speed. Unlike in commercial jet engines and GE's F-120 design, bypass dry thrust is negligible in military engines so SFC is hard to control. The bigger the engine the more fuel it naturally consumes, and the F-135 is simply part of that equation. P&W have in recent years had several debacles concerning SFC on their engines, hence why they market share in the global engine market has sunk into single digits. I don't have inside knowledge of their core architectures to comment on what causes the problems but suffice to say its a systemic design problem that they have only now begun to rectify.
Look forward to more of these little debates. We both learn something new eh...
remember that the F-35 is supposed to use ADVENT in the future
ReplyDeletehttp://www.flightglobal.com/articles/2009/10/21/333770/usaf-advent-upgrade-feasible-for-f-35-engine.html
Sorry to jump in so late in this debate, but here is my 5 cent:
ReplyDeleteThe Gripen can supercruise, the first A prototypes did it in clean configuration during developement with the standard RM12 engine (upgraded F404). AFAIK The trouble with going supercruise is that when you go beyond M=1 the inlet temperature rises due to the shockwaves and this rises the temperature in the whole engine, the turbine inlet being the critical point. Therefore you often needs to trottle back slightly to save the engine.
If the gripen have enough exess thrust or if it is the engine that can stand the increased temperature I don't know, but it can go beyond M=1 without afterburner.
The gripen NG prototype with the F414 engine have enough exess thrust to go M=1.2 with an "Air to Air loadout", I guess (don't know) at least two AMRAAM and two Sidewinder.
The Gripen is a very slender airplane, and in supersonic cruise the main contribution to the drag is wave drag, this is counteracted with smooth area distribution and high slenderness.
As for the F-35, well, I stand down from that debate.
Best Regards
/RAF
RAF.
ReplyDeleteis that real. the F414 puts out 22,000 pounds of thrust but the Gripen NG has ballooned to over 33000 pounds take-off weight.
i imagine those must be some very specific conditions for it to achieve super cruise.
and that's my point. i bet the other aircraft have to operate in very specific conditions in order for them to accomplish this.
I'll be back..
ReplyDeleteOn supercruise utility
ReplyDeleteI have a fairly simple take on this, air combat is all about geometry and time so in this regard the ability to go fast is always a good tool to have in the box.
If you can have speed whilst sipping, rather than gulping your finite amount of fuel, then surely this is a positive all things being equal
ThinkDefence.
ReplyDeleteGood, you're over here...got a question for ya.
has anyone in the Royal Air Force or Navy published a paper on how they'll use super cruise in a combat situation.
your theory (and those of RAF and Ron) all sound valid but that's the next big mystery. why haven't we seen a professional pilot write about this!?!?!?!
Being a lower and thus slower fighter is not all bad. Aircraft above you are visible against a clear sky with no radar ground clutter to reject. A higher aicraft will suffer some loss in radar detection range on a lower aircraft due to the decreased signal to noise (higher Constant False Alarm setting) even when Pulse Doppler is used.
ReplyDeleteSol, not sure, will have a look
ReplyDeleteIn a CAS context its very useful because it means you can cover a larger area (faster response) without using up your fuel and having to conduct an airborne refuelling, thus breaking up your availability which needs another aircraft to cover for you.
Not necessarily a pure combat advantage but the logistics and operational benefits all stack up when taken in the round, you have zero combat potential if you are spending most of your time on the ground or in the air filling up the gas tank.
Air forces also operate not one on one, but as part of complex and integrated package consisting of ISR and equipment like AWACS/E3/ASaC so having more useful speed at a lower fuel burn rate gives the fellows sitting behind their screens in an AWACS more options to get the pointy things into firing positions
I suppose you would also have to define what a 'useful load' was to get a sensible answer as to why it is useful, or not.
ReplyDeleteIt is also interesting to wonder if an aircraft flying at just over the speed of sound or just under has any inherent advantages or disadvantages over the other, if we are using a single point definition rather than a sliding scale
Concorde supercruised so it could stay supersonic with a usable load and fly across the Atlantic but the Blackbird was designed to use mostly afterburner at high speeds to get the massive performance at almost any cost it needed, they still used massive amounts of fuel though
The 1960's era Lightning could supercruise (funny that the F35 is also called Lightning!!) as well
All down the to design requirements, does the F35 have a requirement for supercruise, if not, what's the problem, it is obviously not a priority in the complex balancing act that is an aircraft design.
If you can get to where you are going and still have enough fuel for for some full on afterburning action then this is an advantage.
In general, I think the whole issue is wrapped up in fuel efficiency, engine wear and positioning rather than anything else so perhaps it is hugely useful but only one aspect to be considered in the design process
Hi Solomon, sorry for the delay in reply.
ReplyDeleteThe Gripen NG have substantially increased the maximum take off weight, but the operating empty weight have not increased with the same amount.
The outer contour is basically the same, so the skin friction drag and the wave drag are unchanged (basically). And in supersonic flight the wave drag is the main contributor to drag.
As for the conditions for supercruise, for the A and C model of Gripen, yes, there are very, very limited, but for the NG the envelope is much increased. Of corse it is not as fast as the F-22, but I think it is safe to call it a supercruiser.
my 7 cent.
A few more comments:
ReplyDeleteA few guidelines for structural design I've picked up:
Temperature on the airframe is not the critical factor below M=2. Aluminium can withstand about 100 deg celcius before it starts to loose to much of it's strength, and GFRP and CFRP has about the same temperature limit before the matrix starts to degenerate.
And remember, up at 45k feet the outside temperature is around -70 fahrenheit.
AFAIK temperature wavelengths around or lower than the boilingpoint for wather have a relatively short detection range due to absorbtion in the atmosphere. (Or something like that) What I'm trying to say is that for long range, it is the parts that are very hot (like engine exhausts) that will be visible first.
As for the usefulness of supercruise, I'd say that an advantage in speed is always good, then if it is over or below the speed of sound that is maybe irrelevant.
Sorry for my spelling
Best regards
/RAF
ok, so i have been reading the posts and quite interesting, now i know they have special suits for pilots but i am wondering does supercruise with the extra stresses make the pilot fatigue faster than usual, and if gets into a dog fight situation maybe take down situational awareness? i agree with sol but a pilot writing but i want to hear how it affects the pilot, even with advanced suits.
ReplyDeleteHi all, I am a aeronautic engineer. you need supercruise in air combat. If you fire a missile and you are supercruise the kinetic energy of our airplane and your load (i.e. your weapons) is greater than if you do it at a subsonic velocity (a really silly example try to through a stone if you are running and compare it if you do it when you are just still
ReplyDelete. I.e. your missile run longer, you have a basic advantage in air combat. Regards Guillermo
PS: Joe, I do not think that the pilot will stress more, all of these airplanes have fly by wire so for them is the same.
Regards
PS: Sorry for my spelling.
already discussed Anonymous.
ReplyDeletebut fighters currently light afterburner for those type shots.
super cruise doesn't add anything unique to that situation...unless you're a stealth fighter and once the plum of your missile lites off, then you might as well be 4th gen.
Hi Salomon, I will take your pooint, It's me guillermo again.
ReplyDeleteBut even if you are "5th gen", as the people of Eurofighter pointed "Eurofighter found that four Typhoons supported by an airborne warning and control system (AWACS) defeated 85% of attacks by eight F-35s carrying an internal load of two joint direct attack munitions (JDAMs) and two air-to-air missiles" http://www.flightglobal.com/blogs/the-dewline/2010/07/farn10-eurofighter-boasts-typh.html
In this kind of scenarios witch are not Afganistan when your enemy as well have AWACS, having afterburner can be the difference between come back or have a nice ride on your parachute.
If you have supercruice, after you fire your missiles you just turn as fast as you can with out consuming all your fuel.
How Eurofighter defeated a attack from a aircraft that is not yet operational???Playing cards???Or in Playstation???
ReplyDeleteKeep in mind that supercruising at 100% MIL can double fuelflow compared to a max range profile.
ReplyDeleteI did some diggining into this subject for a book research. RAF and Luftwaffe literature has listed Eurofighter at Mach 1.1 and 1.2, respectively, in a combat ready air-to-air config. The F-35 is estimated at Mach 1.05 in "certain weight conditions" and early/late block F-16s will do Mach 1.1 with 4 AAMs or 2 AAMs + centerline in cold weather and ideal conditions.
As for Gripen, a somewhat dated reference from the Gripen Demo pilot:
"The JAS-39 C/D today could reach the speed of Mach 1.05 without A/B, but only during the cold season of Sweden. We anticipate that after replacing RM12 with F414G, the Gripen NG shall be able to supercruise with the speed of Mach 1.1 in standard aircombat configuration during normal weather."
Recent SAAB marketing notes Mach 1.2+ but it's unclear whether it's clean or combat ready.
All this falls into the marginal supercruise capability. Is it tactically significant to be able to go 10% faster in MIL at the expense of fuel and engine wear?
B. Bolsøy
Oslo
Sol, what a JSF centric blog you have going here my friend! So if Eric's blog is F-35 hell, this must be F-35 heaven? Since we long ago called a truce, I will withhold comments on supercruising and I'll enjoy reading your blog. Keep up the good work.
ReplyDeleteCheers,
RSF
RSF,
ReplyDeletetruce? why yes we did, but its still good to have you visit my page.
Concorde and Tu-144D/Tu-144LL can super cruise at Mach 2.0+. No fighter jet can do that.
ReplyDelete