TooCool_12fthe yf22 model in a wind tunnel in the 90’s.
well i guess that proves it LOL
would you like to try again ?just out of curiosity, what are you claiming for the max aoa and the aoa on roll [pre-stall] on the rafale, about 30 and 20 ?
try what? On the F-22 the modifications were done to increase pilot’s field of view, but aerodynamically, lesser sweep means also lesser efficiency in vortex production: that means the regular F-22 does “worse” than YF-22 as far as lift at high AoA is concerned.. if it’s not clear enough, I can’t help you…
as for “what am I claiming”, I don’t claim anything, you are the one who claimed the F-22 does some “wonder-rolls” @ 40° AoA and whatnot… cold fact is: from aerodynamic PoV it manages to stay airborne because of its thrust and TV and beyond 40°AoA its roll is much better defined as “leaning sidewards” than rolling… it’s an excellent aircraft, but there’s a difference between what it can do and what its fanboys claim it does
TooCool_12fthe cobra is a post stall maneuver
the f-22 stalls at ~60+ and can roll at ~40 aoa, obviously this is pre-stall and the wings have lift
i think you are thinking about your favorite plane, ~30 and rolls at ~20 AOA
ok, let’s see, the YF-22 (higher leading edge sweep giving it a slight edge in AoA over the production F-22 btw) , without TV could roll up to about 20°
you can see the chart here (page 15):
http://www.aoe.vt.edu/~mason/Mason_f/F22.ppt
now, when you look at the page 10, you see wind tunnel data.
@ 20° AoA, there are already vortices that appear over the wing so the airflow looses its “laminar” caracteristic and at 30° there’s simply no laminar airflow left… all the airflow above the aircraft is made of vortices.
That means simply that aerodynamic controls are of no use as such little above 20° and the aircraft needs TV just to be able to stay controllable and use horizontal stabilizers differentially to roll.
On the page 13, you have a chart showing when it can use the TV: under 225KIAS and partially above that speed at low mach numbers and low altitude (faster and higher it can only use it to increase its instantaneous pitch capabilities). That brings us back to what I said: to roll at 40 or 60°, the aircraft has to be slow (otherwise it can’t use TV and without TV it can’t roll above 21-22° AoA)
To finish, if you look at the chart page 15 again, at 40° AoA the roll rate is around 10°/s, so, not only the aircraft would be way too slow but the attained roll rate is not exactly something spectacular
TooCool_12factually, there two most probable options are either
– 2nd (or even 3rd) hand F-16s which they may have for almost nothing.. and the US would secure, sort of, that airspace by being able to monitor quite a number of things they get.. just in case
– Mig-29 variants, maybe even the ones Lebanon was offered for free… lebanon would prefer helicopters instead, and if russia has no real use of these, they can easily get rid of them in favor of serbia. Just as for used F-16s, the initial cost would be very low (if any) and for serbia’s politicians, it brings several advantages over the US equipment: population may appreciate more after the events of the 90’s, the supply wouldn’t be controlled by the US in a way it could be if western equipment was used, and, of course, they already have the type and most infrastructures to maintain them (they even maintained other countries’ migs before wars in the balkans) the mig is also better suited to the defence structure that relies havily on “off-airfield” operations… during wars, migs were spread all over the country, which they wouldn’t have been able if they’d had F-16s, for example
the gripen may sound interesting but, from the price standpoint, they probably wouldn’t be able to propose anything comparable to “free” aircraft
rafale, while costing a lot, may be interesting not as whole aircraft but rather as source of partnership. During the 1980’s, Yugoslavia started developing their new aircraft and they partnered with the french for it. It was to be a light aircraft, one engine (same as the rafale) and overall shape was quite similar. As the chances are simply nonexistent that serbia gets the fundings to buy rafales (unless they find a huuuuge oil reserve under their soil, but then, chances are NATO would find a new interest in “restoring democracy” or something similar overthere :D), dassault and the french government may find interesting to make a partnership to help develop it, integrating some of the systems of the rafale into that airframe. With lesser capabilities than the rafale, that may be an interesting way to create links, have a customer for products like the engines, avionics, missiles etc… and make money selling equipment for serbias aircraft as well as for those they may export into countries where the rafale wouldn’t stand a chance anyway, while for serbia it may mean a sort of “independence” with a domestic modern aircraft type tailored for their needs, while in the same type it would create new jobs and, eventually, generate benefits from possible export markets. Such aircraft may be developed quite rapidly and with costs that aren’t too high (integrating existing equipments into an airframe that, aerodynamically, is relatively close to the rafale’s one)
Su-27, too costly… and what use would serbia have of a fighter with such range? two most distant points of serbia are about 200 miles apart (north/south) and some 100 miles in the direction east/west. Even the mig29 with its notoriously low range can go in full afterburner from one part to another and still have some time to remain airborne left.
F-18, way too costly.. unless the US propose as a “gift” a few old and rusty ex-NAVY C models, there’s no chance serbia finds the money to buy (and maintain) some
TooCool_12fno, you just repeated it, the roll rate ps was worked out on a previous page
and the ability to roll at a high aoa is about 2/3 of max
the rafale probably has about at about a 20 deg aoa roll ability
compared to about a 40 deg aoa roll for the f-22
and?
what good does your 40° AoA mean (not to speak of the 60° claim) if you’re so slow you pull barely 1.2Gs while having it?
AoA as such means nothing. There was an article about USMC pilot who went to russia to fly the Su-27 with Viktor Pugachev. When they made the cobra the first time, while he expected something rather violent while going all the way to 100+° AoA, the guy was suprised at the low G they experienced… The reason is simple, if you’re fast, your increase in AoA will generate a tremendous increase in G’s, way over pilot’s and aircraft’s resistance, until the aerodynamic stall. There, your wings don’t lift anymore, the air is turbulent over the extrados and you pull very little G’s. Now, to avoid that “too high G’s”, you must be sufficiently slow before you do so (Su-27 performs a cobra while doing something like 450km/h (246kts) max. Now, once your wings don’t lift anymore (which is basically what happens at 40 or higher AoA since the air won’t magically go around the wing), your aircraft generates, from the aerodynamical stand point, about as much lift as a barn door. At that time, you maintain your flight primarily because of the thrust available from your engines… there’s no way to pull any significant G’s, which means, unless you have a fabulously efficient off-boresight missile that you can shoot in such circumstances, you’re a sitting duck once you pulled your nose at such AoA.
TooCool_12fanother thing to point out, the A330 assembly line that’s supposed to open if NG/EADS get the contract won’t only built tanker airframes, but all civilian cargo A330 airframes, which is even more work than the 767 line will produce since it will only make the tankers
TooCool_12fno then i was saying the the f-22 could roll at a higher aoa
the rafale has a higher roll rate per second, as we have worked out
thing is, it’s not just your AoA that’s important, but the lift you generate.
take for a second the 60° AoA claim… what good will it make to you unless you’re trying to shoot at someone already somewhere in your rear hemisphère with an off-boresight missile? You can’t see a thing in the area where you’re going, can’t manouver nor shoot at the other guy (canon), and you’re going veeery slowly anyway (besides you won’t be generating much lift since the air around your aircraft will be turbulent and generate almost exclusively drag)
what counts is to be able to pull useful G’s (the more the better, since it shortens your turn) while retaining your manouverability, and the rafale can roll at will basically through its entire envelope (somewhere around -3G/+9G, some have even written that the limiter could be switched to 11Gs if necessary)
And then, you get to a point where both aircraft will reach their G limit (if their limiter is set for the same limit, which is 9G’s for many fighters that means that only what will make the difference will be the fighters ability to maintain the G’s and do so while having a lower speed than its oponent. That’s where the aerodynamics come into play. The raptor was made to go fast and far and that means, they had to make it sleek with as low drag as possible. The rafale was made with agility as target, as well as the capability to carry heavy loads.
As a result, both have their strengths and what will make the difference is mostly the tactics employed… this was the first such encounter (so they had to learn a bit about each other), but chances are that, in the future, others take place, which will make the things quite interesting
TooCool_12fBlue Apple answered right..
to produce lift, you act on the air, and that produces turbulence (simply speaking) and that turbulence generates drag in proportion… the higher the lift, the higher the drag produced (or induced if you like)
TooCool_12fconsidering “sustained 60°+”… that would mean the aircraft is flying really really slow. You can’t pull such AoA and keep it there at normal flying speeds. At such angles, the aircraft basically acts like a giant air-brake… you lumber around wasting gas and not doing much else..
much more important than the AoA you reach are your corner speed, your turn rate and the agility of your aircraft (ability to change manouvers rapidly)
Another point is, how good a fighter is in producing lift? When your aerodynamic shape is made to give you the ability to go supercruise, that means you have a low drag (which means also “low lift”) profile. Both go together. High lift required for hard manouvering at lower speeds will be harder to produce, which will limit your capacity to pull G’s as the speed decreases. Being lighter and more optimised for carrying loads and manouvering, the rafale may very well have an edge in manouverability even if its engines don’t produce as much thrust as the F-22’s ones when the speeds gets down.
Thing is, most numbers that would be necessary to really be able to compare the two are classified, for both of them… so, where the truth is: probably simply in the fact that both aircraft are excellent fighters, and on this board we won’t be able to go much further…
TooCool_12fas per airdefence,net for the same flight distance load of fuel the rafale doesnt have better t2w the f-22 f-15 lead the list by far
what is the rafale roll rate per sec ? as i havent seen it
i think i have a reasonably grasp of AOI/AOA, i have no need to ‘show’ you, i dont rate your opinion that high
rafale’s roll rate was given in a post right above your previous one:
Rafale: 270°/s
you gave F-22: 200°/s
that would mean, that the rafale actually outclasses the F-22 in that area (and the F-16 does the same, btw)
TooCool_12fif they really have too much money in their pockets maybe…. but that’s even more unlikely than RN buying rafales tomorrow.
India has bought Airbus tankers before politicians changed the decision (reminds me of something… :rolleyes: ), officially because there’s a law saying they HAVE to take the lowest bidder… seemingly that the qualities of the aircraft don’t matter.
If you apply that way of functionning, they’ll only buy Migs for their carriers, since nobody else will be able to propose a lower price
TooCool_12fI agree, but define happy Medium?
TooCool_12f brought up the preposterous scenario of a fighter pilot being forced down because the tanker ran out of gas. :rolleyes:
man, if you can’t understand irony, then you shouldn’t post on public boards, since you won’t understand a large part of what you read, period
TooCool_12fAgain, with your argument, why not buy A380s? Or replace all C-130s with C-17 or A400s? There might be a time when you need a bunch of gas in one plane?:D Do you have a 1-tonne truck instead of a Golf?
Same principle.The USAF knows what it needs/wants…don’t try to second guess their them into buying something larger than they need.
er, 1 ton truck instead of a golf? I have a “small” 20 year old mercedes that weighs 1.1 ton, and it’s a pretty “light car”
your “1 ton” truck is just a very small van… some people do have much heavier things. like all US pick-up owners 😉
anyway, back to aircraft.
The A330 gives you more than the 767, but in the same time the price difference isn’t proportional. Basically, if you get 20% more on a certain performance type, you don’t pay 20% more. Still, if you don’t take into consideration the advantage it gives you, obviously, the price alone that’s slightly higher makes the deal look worse than it is.. that’s the whole problem:
the way things were asked shows clearly that the will behind the RFP is to take the smaller aircraft, even if the USAf prefers the other one… and that’s also why NG/EADS may refuse to participate.
And if they do so, well, the result will be fixed price on initial batches, and then, boeing will make their profits on later ones since without competition, they’ll be able to increase the price at the taxpayers expense only… basically, that may be NG/EADS’s way to tell the US congress: “serves you well…”
If you make a competition, but say “I don’t care who’s better”, you can’t expect anything else but the lowest bidder… which, usually, ends by costing more and giving you less
TooCool_12fTen years earlier, the US put up 78 bombers IN A SINGLE RAID from Guam to Vietnam–not an inconsiderable distance–and it didn’t require 585 tankers to get the job done. Why? Boom refueling.
Cheers,
Logan
There’s only one problem with your statement:
The RAF bombers are tailored for european theatre. They don’t have the range, and neither their tankers do, to go so far. And, add to that, their tankers have less transferable fuel onboard, which means, less fuel to give than a KC-135.. much less. Result, they need to refuel, all of them, and not only once… and that means, other tankers have to go with them to refuel them… and other tankers have to go to refuel the refueling tankers… that’s why it was so “complicated”
add to that that the vulcan had to do its final part of teh mission at low level to stay under the radar, so the surprize effect can be achieved for the bombing run (more fuel burned again)
You can read “Vulcan 607” by Rowland White, if you want “inside info” about that mission.
TooCool_12fQuite a point, still, finding a contest that even approaches the notion of “clear” is not exactly the easiest task, don’t you think?
of course, in such deals it’s always about politics anyway, so “clear” isn’t the first adjective that comes to mind when thinking about it… 😉
I was just responding to a post saying that “sold numbers prove the aircraft quality”, which would, under the context, imply that the typhoon, since bought (or ordered in bigger numbers than the rafale) was obviously better… My remark, therefore, was just considering the way the typhoon got its exports, and it didn’t seem so directly related to the inherent quality of the aircraft
TooCool_12factually, it seems that some parts aren’t delivered due to various modifications (normal, since the tests reveal need for corrections here and there), so LM has to ask other subcontractors (who can deliver on time) to delay their own parts because there’s no place to store them… and at the same time, they have to cannibalize some aircraft on the line to finish others…
for now it’s quite a mess which should be sorted out once they come close to the end of testing and the final product is more or less known and approved.
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