FBWno, none of them met acceleration threshold from mach 0.8 to 1.2,
and it was described as a very cumbersome job to finally get f-35 to top speed, and gas tank was bingo when it finally made it there.
F-35 accelerate fine at low speed (air show speed) due to thrust, but drag hamper it from transonic on
and it is a poor performer at combat speed
Why do you post when you have no idea what you are talking about?
The F-35B required unloading to reach Mach 1.6. Note, it is not the same as the “A” nor does it carry as much fuel.
FBWBecause the f-35 has DSI not fixed ones, so it is not so hampered into a unique flight regime, still it is slower than all the rest of the bunch: so what can it be if not ’cause of a draggier frame? It is maybe underpowered? Doesn’t seems me as the F-135 is probably the engine with the greater T/W ratio around.
Or are you being puzzled by the use of the use of the verbal form would instead of will in the phrasing? In this case, my fault: I’m not a native English speaker so i probably trasferred a my language form into it.
I
No, no and no. The F-35A has exceeded mach 1.6 in testing. The operational limit is 700 knots/mach 1.6, obviously it is not the drag limit. As everyone above has tried to explain to you, simple airframe drag is not the limiting factor, nor is static thrust. The requirements were 700 knots across all three variants. The inlet design, most likely is tailored to that requirement. Just because other aircraft with DSI have a higher top speed does not mean anything. As I’ve pointed out, the F-15 is has a higher drag coefficient, and higher overall supersonic drag than the F-4. It can exceed the F-4’s top speed, not simply because of more static thrust, but dynamic thrust. It’s inlet design, materials, and aerodynamic limits allow it to reach mach 2+ speeds in theory.
So why is the F-35 operationally limited to mach 1.6/700 knots? One- that was the requirement. Two- most likely the inlet design. Three- because the tradeoffs for higher speed aren’t worth it for a strike fighter that needs to fly efficiently at subsonic speeds over long distances. The F-16, technically, can reach speeds of right around mach 2/ 800+ knots. But, in reality, once pylons and missiles are added, those high speeds are no longer attainable, same with the F-18. The F-35A will be every bit as fast armed (perhaps a spread of 30-50 knots) as the aircraft it is replacing and have better supersonic persistence.
FBWIsrael will be getting 50 F-35 it seems; and they are hoping for another 25 (potentially B’s) bringing the total to 75.
http://www.iaf.org.il/4447-46784-en/IAF.aspx?kjdf
As I have said before: no doubt the F-35 is unique and very powerful — however that begs the question why only 75, why not replacing all their F-16 and F-15 with F-35? We all know that operating more than one type of fighter is extremely expensive. My guess is that the reason why they want to stop at 75 is that the F-35 is very expensive.
Why do you assume that the procurement of 50-75 F-35 implies some negative about the aircraft, such as expense? First off, let’s be clear, Israel is not paying for the F-35 solely from it’s own defense budget.
The IAF love their “Baz”, yet only received roughly 57 F-15 A-D. They would not be replacing all their inventory with F-35 anyway. Their “Ra’am” and “Sufa” are relatively new.
FBWThe F-22 gained weigh————–what an under statement. If you google the F-22 the empty weight is listed as 43,000 pounds vs the F-23 empty weight of 29,000 pounds.
There was no F-23, so 29,000 lbs is fiction. The YF-23 was reported to have an empty weight in the low 30’s. So, I’m not sure where you are getting your estimates from.
Both the YF-22 and YF-23 were true prototypes. No sensors, obvious modifications such as a nose that could fit a radar needed to be made. If you read the backstory on the ATF project, they knew the production aircraft would end up weighing around 20 tons. Engine thrust was planned around that assumed weight growth.
FBWThanks.. but you both have misunderstood my question.. By asking why wasn’t the F-35 designed for greater speeds I didn’t mean “why won’t it go past M1.6?” rather than “why can’t it spend spend most of its time at M1.3 using military thrust only?”..
F-22 aside, (as we disagree on its capability), other than a “check the Box” marketing claims, which of the supercruisers possess both the range and speed armed for operational utility in this regard?
That is one thing both hopsalot and I were pointing out. The f-35 mantaining supersonic speeds for 150 miles is tactically useful be it with minimum augmentation, no augmentation, whatever. Furthermore, possessing that capability as a single engine strike fighter, not an air superiority fighter.
FBWAnd why wasn’t the F-35 designed for greater speeds? 🙂
Same reason that the F-18, F-16, Typhoon, Rafale are limited to around mach 2 or less (conflicting information on F-22, but reportedly limited to roughly mach 2). The added complexity and design tradeoffs to achieve mach 2+ is not worth it as operationally, those speeds are never reached. The F-35, for all of hand wringing over mach 1.6, is more likely to reach those speeds operationally than the F-16’s and F-18’s that it is replacing in US service. It obviously is not drag limited to Mach 1.6 (at least not the F-35A), as it has achieved mach 1.67 (10% testing margins- flown to mach 1.67, 9.9g, etc.). Anyway, it is a 700 knot aircraft, and the F-35A is required to exceed mach 1 at sea level. It is expected to reach 700 knots with weapons and deploy them at those speeds (which for those who’ve read DOT&E report know that it cannot right now, no need to bring it up- obviously they are addressing the weapon bay issue).
Again, those who harp on this really don’t understand that those fourth generation fighters, while capable of high speeds, are actually draggy at supersonic speeds. Design tradeoffs: superior agility and efficient cruising at subsonic speeds, or high sustained supersonic speeds. The F-35’s design was influenced by the operational experience of the US fighters of the 70’s and 80’s.
FBWthis is interesting, can you explaine in more details?
Which part? About the F135? Or different augmentors?
FBWWhat are you talking about?
Obligatory stating that exceeding mach 1 in dry thrust is supercruise. Really, it would be different for all aircraft. If you define supersonic flight as the upper critical mach number (as in all airflow around the aircraft, not just wings, is supersonic), then one aircraft flying at mach 1.2 could still be experiencing significant wave drag and another not.
There are a number of factors determining this: wing sweep, aspect ratio, t/c ratio, supercritical wings, conformity to sears-haack shaping, etc. That would be one reason for the USAF defining supercruise in the F-22 at mach 1.5. The stabilization of flow and reduction of wave drag at speeds in excess of mach 1.2-1.4.
This has been posted before:[ATTACH=CONFIG]246631[/ATTACH] A highly swept wing has a different drag profile,
FBWabout afterburner stage, this is from That_engineer_guy, i think most member here familiar with him
F100-PW-229 has an 11 stage afterburner. The F135 has three zones (lacking manifolds or spray bars of standard engines), and as you are alluding- the amount of afterburner is adjustable between Mil and Max power.
For the -229 the throttle has a little notch at Mil power, and adjustable resistance, to let the pilot know where augmentation begins. The amount of augmentation is throttleable (no different “feel” even with the old multistage ‘burners”
FBWno, supercruise is only sustained supersonic flight without a/b in level flight, how you got there got nothing to do with it
Yes, because all airframes perform the same at Mach .9- mach 1.4. The level of stupidity is at an all time high on this thread.
FBW1] where are you pulling 150 nmi from ?
2] he clearly states that its not supercruise in a technical sense, that leaves only a/b or dive, or deceleration
Or you interpret the quote as it suites you. Even if it could maintain mach 1.1-1.2, it is not a supercruising aircraft. The point is moot. All this talk about the aircraft in a dive et al. is moronic. The design goal was never to supercruise, but the pilot’s statements about the F-35 having a cruise speed some 50-80 knots faster than an F-16 with a similar weapon load is telling.
FBWYou got it, supercruise is just that.. A buzzword, used to promote a certain product (F-22A) as something entirely different from the rest of the world.
The overall distance at supercruise speed, as a part of an overall mission profile, was mere 100 nautical miles, which was some 7 minutes @ M1.5.. How useful is that in a practical sense is anybody’s guess.
Alas, something we are somewhat in agreement on. Supercruise has become a buzzword, but it had a tactical implication when the F-22 was designed. I would disagree on how useful it is for the F-22.
First off, 100 nmi is conservative. Second, the F-22 has a few advantages over the other (so called) supercruisers: low bypass turbofans optimized for high speed/ high altitude (when the USAF states that the F119 puts out more mil power than the F100 in afterburner at altitude, that gives an idea of the design principles), thrust vectoring does reduce trim drag at supersonic speeds, and the F-22 can maintain mach 1.78 in military power. In essence, it can still throttle down and maintain speeds well clear of transonic drag.
Despite what the advertisements say, being able to maintain supersonic speed in dry thrust (mach 1.1-1.3) is not unique, as many of the third generation fighters could do that as well. Being able to maintain that speed clear on the transonic drag hump while armed is the domain of very few. It is ironic, when people talk about the F-35 and transonic drag, they miss the point. The fourth generation fighters: F-16, F-15, F-18, and most likely Su-27/ Mig-29 actually experience much higher transonic drag than the aircraft they replaced. What changed was the power to push through the transonic region with afterburning turbofans that are much more fuel efficient at subsonic speeds and more powerful in afterburner. The much maligned “air power diesel” F-4, has lower drag in the transonic region than any of the US fourth generation fighters. When the pilots say that the F-35 has a higher cruise speed and altitude and is more capable of maintaining supersonic speeds than the aircraft it is replacing, they are not lying. It is a simple question of fuel fraction, thrust, and engine efficiency.
VAT/ADVENT should provide that breakthrough. An engine that can maintain supersonic speeds without the spiral of a large fuel fraction/ large airframe, and cooling issues. The third stream can provide the needed cooling capacity and efficiency to make a next generation fighter truly supersonic.
FBWQUOTE=logical1;2319850]If you look at the specs on the two aircraft, the Widow has more wing area, is lighter, and has the same engines.
The YF-22 was reportedly lighter than the YF-23. In the evolution to the F-22, the design gained weight. There is no reason to think that the evolution from YF-23 to F-23 would have been different. In fact, the YF-23 EMD would have included significant changes ( would have added second small weapons bay, larger nose, redesigned engine nacelles). The YF-23 was deemed riskier on the very basis of modifications needed from prototype to EMD.
That means the Widow would have better performance. People that claim to be in the know said the Widow flew faster and higher, with more stealth. If you are higher, faster, and cant be see by the enemy, you are the victor.
General consensus was that the YF-23 was “stealthier”. Yes, the YF-23 was faster than the YF-22. However, the F-22, as evolved was faster than either F119 powered prototypes in supercruise, but there is no way to say if the F-23 would have been faster still. The F-23 would have reduced area ruling, and redesigned nozzles.
FBWyes, but we are talking about miles here, not nautical miles, so whats the fuss with nm ?
Might have just a little bit due to its use in aeronautics, hence aircraft speed measured in knots. Laying on the sarcasm pretty thick here.
FBWhe starts out by stating its not supercruise in a technical sense, i.e not level flight,
and a dive will inevitably be limited in range, before unpleasant stuff happen.
the other comment therefore refer to level flight, when it takes a teeny weeny bit of a/b to stay supersonic.
then we got L.M, whom stated it doesnt, period
Yeah, a 150 nmi dive….. Starts in U.S., nose pokes out in China.
Back to reality, seems this needs to get rehashed every six months. Whatever O’Bryan meant in his quote, supercruse was never an objective. Two more pages added to hash out what we knew a long time ago. As hopsalot pointed out several posts ago, the critical takeaway is that the F-35 can fly a tactically significant distance at supersonic speeds, if need be. That is already a step up from the aircraft it is replacing.
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