RadDisconnectBasic range formula is logarithmic with respect to ratio of final weight to initial weight, so range increase wouldn’t be linear. That being said 760 nm is a rather substantial increase. Perhaps a different flight profile?
RadDisconnectFor sure you don’t realize that several naval planes have no HT ( rafale, and concepts like F-23N and Boeing’s 6the gen ), maybe you forgot that. :rolleyes:
Did you even bother reading the sources? I never said carrier aircraft can’t be delta canards, only that the F-35 isn’t one for reasons I provided. Here, want an additional source?
Go to page 83:
Lockheed assigned the JAST program to Skunk Works, where the CALF program was already in full swing. The same basic design proposed for CALF (rear wing and forward canard) was used in the early JAST studies… All through the CALF and early JAST program, Skunk Works had proposed a design with a forward canard. This had begun to create troubles when the navy’s requirements were taken into account.
The Navy was the latecomer to the JAST/JSF program, as they joined in when it became clear the A/F-X would be cancelled. Some of the weight-adding features like the two 2,000 pound bomb requirement was the result of the Navy, not the Marines or the Air Force. How about a photo of the Lockheed test vehicle for CALF?
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Clearly it’s STOVL that made canard impossible. :rolleyes:
RadDisconnect???? So, in your opinion F-22 , ordered just by USAF would have been a delta/canard? It got also thrust vectoring so it would have bee an ideal candidate for such a configuration
European preference for the pure Delta stems from the fact that they have a long tradition for it, both in France (Mirages) than Sweden.Canard were considered not an ideal choice in regard to stealth signature, so not a surprise that instead americans don’t have considered them at all.
I never said if delta canard is better that wing tail configuration. It depends on trade studies done during the design, and it can involve any number of factors. One is not necessarily better than the other. And what’s with the canard debate? Northrop’s NATF would have had a canard as well. And read July 1996 Code One magazine article on the JSF development, page 27.
http://www.codeonemagazine.com/images/C1_V11N3_SM_1271449318_7528.pdf
When the government merged the JAST and ASTOVL programs in late 1994, that baseline shifted to a wing-canard design that Skunk Works had been developing for several years.
…
The Air Force and STOVL variants were tailless, delta designs. And the Navy variant had a stretched fuselage and fuselage and wing-tail planform. Affordability factors pushed our approach to a much more common family of aircraft.
Also, the pair of 2,000 pound bomb was a Navy requirement, since both the Air Force and Marines were content with 1,000 pound bombs. Then you have to add the additional weight required to make the structure capable of accommodating carrier landing gears for the CV variant. The Navy requirements greatly contributed to the aircraft being heavier and bulkier. And it was the Navy variant that drove away the canard-delta configuration of the original JSF. A canard-delta JSF would arguably have been better aerodynamically, since the fuselage from nose to nozzle can be longer for the same given length.
Here’s some more info about the ASTOVL before it was merged into the JAST/JSF.
The results of that study showed that the 3BSD design was significantly lighter than the SERN nozzle. Moreover, the design also showed superior propulsion performance in all modes. The 3BSD was subsequently included in the ASTOVL Configuration 141 – the original canard delta design of what evolved into the X-35.
http://www.codeonemagazine.com/article.html?item_id=137
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But but but delta canard is impossible due to STOVL!! :rolleyes::rolleyes:
RadDisconnectI get the point. 😀
One can see also the large size of the HT, which is due in part to the fact that the moment arm is short.
Had they chosen a longer aircraft ( and slimmer ) with a delta wing ( with around 58 degrees sweep angle like on the Mirage 2000 ) the weight of the big HT would have been removed in favor of the wing, so more fuel would have been carried inside the wing. The ability of keeping the energy high for many turns is mainly useless nowadays, so a delta wing would have been fine. The delta still has a high pitch rate and can pull 9Gs.
Bottom line: longer fuselage with less cross section, and delta. +canards and large flaps for the CV variant or a larger wing around 50 degrees sweep. Of course this is completely impossible with the STOVL requirement.
You realize that the F-35 have tails instead of canards due to CV, do you? Not sure what your fixation is on bagging on STOVL.
RadDisconnect1; Sigh. I know you can read Russian Jo. Everyone knows you can read russian, so why the heck are you lying? The document is clearly stating what that aluminum is for. Also, as i posted here previously; http://forum.keypublishing.com/showthread.php?135806-The-PAK-FA-News-Pics-amp-Debate-Thread-XXV&p=2252049#post2252049
But yeah, i am sure Azohen Vey was lying and so are the developers.
2; Side arrays has been installed prior to T-50-6-2. Radiation stickers or lack of them means jack ****.
Credit to this blogger btw; http://tankasan.livejournal.com/170016.html
So the T-50 can join the group of just about every modern fighter to have gone overweight. Reminds me of McDonnell Douglass situation with the ATF program. To quote Sundog over at secret projects, MDD’s submission was the heaviest of the proposals, which is odd because they’re a company who has traditionally been very good with weight. So was MDD too heavy, or too accurate?
It may be an illusion or perspective issue but does the vertical tails seem to have slightly greater chord? I’m a bit mixed about the nacelles though. It’s nice to not see that much bare metal finally, but I was hoping for something cleaner and maybe less perpendicular panel lines. Maybe that area has been heavily worked with? I know this is still the prototype phase but I’m getting impatient.
RadDisconnectOne piece canopy with internal support frame, like the F-35, although hinging could be challenging. Refined control surface joints to minimize gaps, and closer manufacturing tolerances in general.
The nozzle seems like a no-brainer though, I’m puzzled as to why that hasn’t been implemented.
RadDisconnectSigma4, you’re gonna need more reputable sources than a no longer existent forum post and Wikipedia.
IIRC, an AvWeek publication stated that the F-22’s RCS is as low as -40 dBsm from optimal angles like the front. Not idea how that compares to the F-117.
Interestingly the supercruise speed tends to vary a bit over time. An F-22 fresh from the depot is probably a tad faster than older ones ready for overhaul. It’s generally around Mach 1.8.
Found it. http://m.aviationweek.com/awin/f-22-raptor-make-paris-air-show-debut
RadDisconnectI’m not really sure how advanced the air defences are over Syria, but the F-22 most likely is more survivable there than the F-15, or anything else… so I don’t see the point.
Only 2 tanks, 4 tanks are not cleared. I believe there were structural problems when they ground tested the 4 tank configuration so it was never tested in flight.
Testing from 4 tanks showed that it would shorten the life of the wing due to extra fatigue. It was tested but not cleared for use. Given aerial refueling though, 4 tanks wouldn’t be too useful anyways.
RadDisconnectThe shoot, turn around and run was a standard tactic used by soviet interceptors and frontline fighters with their middle range missiles, always carried in pairs, one IR and the other Sarh, so i’m quite curious why you limit it only to Mig-31.
What kind of mission are we talking about here? Interception? Combat air patrol? OCA or DCA?
Suicide pattern is a way to describe how it would turn out to be trying to utilize the air dominance mission pattern originally intended for F-22 use i.e. sending a plane to loiter over enemy controlled territory against a modern air defence system, it doesn’t in any way imply that F-22 cannot turn out the great fighter it is when employed in another, more realistic way.
Just I doesn’t expect that any future 5gen fighter plane to be designed with the same all round RCS level reduction scheme as the relative advantages it bring are not in any way enought to justified the cost, both monetary than in terms of performances and reliability it would imply.
For the rest, same US MoD seems to have come to the same conclusion and have stopped its production in favor of F-35.
What exactly was the original mission of the F-22? As far as I know it was made to be an air superiority fighter. I don’t know why you’re insisting that loitering over IADS was the design driver of the F-22 and its stealth features.
That being said, the T-50’s lower emphasis on all aspect stealth points do different mission requirements by the VVS, but the details of that are unknown.
The F119 has been fitted with SERN nozzle, two-dimensional non-axis symmetric con-di nozzle, and LOAN nozzle. The difference for the SERN nozzle (as would have been fitted to the F-23) was something like 1.5%. The actual thrust vectoring non-axis symmetric con-di nozzle has little impact on thrust, with the caveat that altering the pitch angles does reduce efficiency. Take a look at the SERN nozzle on the F119 fitted to the YF-23, truly bizarre. The SE611, and SE614 variants that powered the two JSF x-planes the asymmetric LOAN nozzle and do produce more thrust, but are different from the F119 in having an extra stage and larger fan.
The studies indicated that the traditional con-di nozzle had a 10% advantage over non-axis symmetric con-di when considering nozzle weight. Then, when the optimal shape ( illustrated by the F119 engines) was compared with cooling requirements, the non-axis symmetric nozzle was within 1% of the standard con-di nozzle.
SERN nozzle? Also, I’m not aware of the F119 using active cooling for the nozzles.That’s the first time I’ve heard of that. Can you point me to a source? I’m rather curious.
The major advantage seldom mentioned is that the 2-d wedge nozzle offers a significant reduction in drag. The nozzle is a significant source of aerodynamic drag. The F-111 is a great example of this: the designers chose the nozzle that offered the highest thrust potential (uninstalled), unfortunately the nozzle had a significant performance penalty installed (one reason for the “turkey feathers” on the F100). The 2-d wedge con-di also offered advantages in dry thrust settings.
I haven’t heard about the nozzle thing. Based on johnwill who worked on the F-111, for the tail it turned out that a blunt end is somehow less draggy than a sharp end as was found in wind tunnel testing. Rather interesting phenomenon, and I’m not sure if it’s due to the nozzle or some other effect.
From johnwill himself:
Don’t be so sure the sharp trailing edge will result in lower drag. As you say, there’s more to the story. Here are two photos from the early F-111 flight test program showing exactly the comparison under discussion, sharp edged and blunt.
The sharp edge was the original design, but wind tunnel and flight test showed the blunt edge resulted in a useful drag reduction. The pointy ended pods just inboard of the horizontal tails were also truncated for production airplanes.
Sharp eyed readers will notice those are Navy F-111Bs, but all production airplanes had the blunt design.
Original:
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Modified:
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So, in no simple terms: While the symmetric con-di may be more efficient (ceteris paribus) on a test stand, it is not when installed, especially considering the original studies included a large (up to 600lb) penalty for the non axis symmetric nozzle.
Back to the Pak-fa, why not flat nozzles? Perhaps because the designers wanted thrust vectoring on the pitch and yaw axis, or maybe because they did not want to basically redesign the entire afterburner assembly, jet pipe, for an interim engine.
Do you have further readings about the matter? I’m curious.
The F119 engine weighs about 4,000 lb, so is in the same weight class as the F100 and F110.
According to the best data I have, the F-22 weighs 14.4 tonnes when empty, and can carry 8.2 tonnes of fuel internally.
Official data for the F-22 is that empty weight is 19,700 kg, so your figure may be weight without engine installed. The fuel load is 18,000 lb, so around 8.2 metric tons. There was a technical order floating a while back that suggested slightly higher fuel load, but every source that came after always pointed to 18,000 lb, so it may be an error in the order. The F-22 does have rather low fuel fraction, which is actually one of its greatest shortcomings: limited range, especially for the Pacific.
It seems like the PAK FA won’t have problems with range. I think all was stated was that the T-50 has more fuel than the Su-27 (20,700 lb, 9,400 kg) but precisely how much we don’t know.
RadDisconnectEnormous, I wouldn’t say , it’ s just larger due to larger relative dimensions, but it’s not that radar range is directly proportional to RCS, so detection range of a 10 sqm target is not 10 times larger than one of 1sqm only.
Real difference is between front and rear aspect: one is the easiest to adress while the other a real pain.
Exaust nozzles are the main problem for this in both the radar than IR but no one other VLO fighter designerhas ever tried to try to resolve it at the expense of other fundamental performances and reliability parameters in the way the F-22 was forced to do by its own specifics.
On what grounds can you say that the nozzles were designed at the expense of fundamental performances and reliability parameters? Do you know what the reliability of the F119 nozzles are?
This for a fundamental reason: the greater RCS of the rear is more than compensated by the reduction of enemy missiles useful range between an head on and a tail-on engagement, so if your intended missions are basically snoop and scoot ones i.e. approach target (ground or air) engage it, broke contact and run away at maximum speed you are quite safe the same. F-22 one WAS NOT SUCH.
More than compensated? This “shoot, turn around and run” description is grossly simplistic assessment of air combat. All aspect RCS is important not just in egress. Also, this assumes that whatever aircraft that uses this method for survival dash away at maximum speed more than F-22’s, i.e. Mach 2+, something the T-50’s was simply not designed for. The T-50 is optimized for sustained supersonic cruise and high levels of maneuverability, NOT maximum dash speed (neither is any modern fighter aircraft other than interceptors), so its not designed with your “tactic” in mind, and in fact no air superiority fighter can even attempt this; the only aircraft that can try is the MiG-31, but that aircraft is designed for a fundamentally different mission from the T-50.
MALD-J entered service in september 2012 i.e. after that F-22 assembly line was removed, packed and sent to Alaska.
In every case what I said in my post still stand: even in such a case F-22 would still have to carry it with itself the same to be able to use it while staying for long periods of time over enemy controlled territory as it was envisaged in its original intended mission pattern.Despite i have seen not any ufficial statement , I just assume, given the sudden and premature end of F-22 production and the fact that all of them are based in US territory, that such a suicide pattern has been just quietly dropped out but if someone has something more about it, I would be happy.
Now, back to PAK-FA.
And how does the MALD-J factor into this? I’m curious as to how you can judge something as “suicide pattern”.
RadDisconnectRemember the F-35 is brought to you by the same B’crats that bought the F-22 rather than the F-23. The 23 was faster a was a better stealth aircraft.
Strike fast and unscene. That was what the greatest fighter pilot ever Erich Hartman did.
The YF-23 was passed over because of Northrop’s bad management of B-2 that made the Air Force lose confidence. It’s an overall more ambitious design with much more supercruise range but it’s also riskier and more expensive, so the safer option F-22 is chosen, which also meets requirements.
RadDisconnectEh? So once again, he claimed 5.5-6.0g, the actual value was 5.4g and you call this utterly and completely wrong? Because of the 0.1g difference? You are not being serious now, are you?
Picard claimed sustained. Sustained. Are you aware of what that means? If so then you should not be making the mistake of assuming that pulling 5.5g is the same as sustaining.
RadDisconnectYou can say the same about problems with the F-22’s nozzles. It’s heavy, it reduces thrust slightly, it needs additional maintenance and servicing. In the end it’s about whether or not the aerosol system meets the Russian air force requirements and what they intend to use the T-50 for.
RadDisconnectIf it is not stored/mixed in the fuel itself, but rather in a separate tank then I see no pros with it.. it will steal volume and add weight.
I seriously doubt they would use fuel for that. I don’t see the problem with storing the material in a separate tank. Its size depends on the flow rate needed to achieve IR reduction goals, and it doesn’t need to be turned on at all times. I’m curious to know what effect this has on the aircraft’s boat tail drag. In any case, this system has its benefits and disadvantages, like everything in engineering.
RadDisconnectI don’t care.. His reference to Rafale is in no way related to the article in question [about the F-35]..
BTW, if you can disprove his figures, then I am all ears..
You really don’t make much sense. Firstly, how can I disprove Picard578’s figures when he provided no proof for his figures in the first place? He listed off arbitrary performance numbers without providing any sources. And how does this relate to the F-35? You’re the one who used Picard578’s blog as a source in the first place, and you’re blatantly ignoring or dismissing our reasons for questioning his credibility. On the other hand you seem to readily dismiss any positive news about the F-35 as paid comments. You don’t see the hypocrisy? If you insist on making blanket assumptions about news regarding the F-35 without any regard for the credibility of the source beyond “if it’s positive then it’s paid for by LM” then I don’t know what to say. It’s like talking to a creationist.
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