Viper vs Raptor: Maneuverabilty

[jimraynor]

There's really no shame in being totally outmatched by the Raptor. Everything is. Even the F-15's top speed of Mach 2.5 is a paper value; it's not going anywhere close to that for a significant period of time while carrying a payload. Raptor is faster than it in practical, usable sustained speed.

"Price" is actually not a joke but a real consideration. You can't have a sizable air force made up of nothing but Raptors. Something needs to be the workhorse once the cruise missiles and stealth jets take out the enemy's air defense. The F-16 performs that role admirably.

[exec]

either way, the Viper turns the FASTER and TIGHTER sustained turn. And remember than while the Raptor has a lower wing loading it also has a worse aspect ratio so induced drag goes up.

Viper turned faster and tighter because it flew slower. If the Raptor flew slower the turn radius would also be smaller. You can’t judge sustained turn rates that way. Fighters often show max-g turn at airshows, but if a fighter can pull 9g at sea level when flying 700 to 900 km/h how can you judge its turn capabilities not knowing the actual speed? Doing 9g at 700km/h means much smaller radius and quicker turn than when flying 900km/h.

Second thing – do you really think that sea-level turn performance is really that important for the Raptor?

[exorcet]

Aspect ratio is defined as span squared (44.5^2=1980) divided by reference wing area (840, 1980/840 is 2.37), when compared to a Vipers 3.0

Yes, but b^2/S doesn't tell you everything. If you had a square wing with the same span and area as the F-22's or F-16's wing, you would get the same aspect ratio, but not the same wing performance.

I was thinking about it terms of the "effective AR" produced by the shaping of the wings, but technically, you're right, that actual AR would be b^2/S. But note that for the lift slope, it's the half chord line that's important, not LE sweep. The F-22's taper would make the half chord sweep angle much less than the LE sweep, but it may or may not be less than the F-16's half chord sweep.

Also, you have to factor in the fuselage lift coefficient/area for turning maneuvers, so the F-16 may not actually require higher wing CL for a given turn.

[sprstdlyscottsmn]

when you have a wing as big as the raptor the fuselage is encompassed in the reference area, and I only ever state wing sweep, I am not nit picking about which angle. A square wing with same span and area would give GREAT lift dues to no taper or sweep, that is why an A-10 turns so well. besides, no one thing "tells you everything" that is why I covered three issues and came up with a result that I did not know.

Exec, at airshows they tend to show off BEST turn rate. They want to show what the jet is capable of and they often announce it as the "minimum radius turn". Believe me I know all about how speed changes the turn, but the first post of the thread was questioning if the Viper had a faster sustained turn, and based on demonstrated performance it does at sea level, but I already stated that the Raptor is designed for supercruise first.

[Patriot]

Looking at numerous youtube videos regarding F-22's and F-16's

Not thrust worthy. Video footage is hugely ambiguous.

Well, I don't think so, certainly not in this case.. There's clearly shown how much time takes to complete the full 360 degree turn. That's simple reference to the rate of turn. Isn't it? The faster you finish the higher your rate of turn is. Every time I checked it out and compared - every time the Viper was 2-3 seconds ahead of the Raptor.

And as sprstdlyscottsmn said, they shows the'd have best to show at air show conditions. Therefore and above I claim that Viper's sustained turn rate is better than Raptor's sustained turn rate.

Check out how Corner Velocity affects the turning capability:

Corner speed also affects the minimum turn radius. The size of the turn radius of an aircraft depends on the speed it is traveling. A faster aircraft requires a larger circle to turn in than a slower one. However, the turn redius isn't only a function of speed. It also depends on the number of Gs a pilot pulls during the turn. An aircraft at a constant speed will make a relatively wide circle at 1 G but will turn in a very tight circle at 7 or 8 Gs. The corner velocity is the speed that gives the optimum balance between turn rate and turn radius.

on the bottom http://www.voodoo-world.cz/falcon/agf.html[/code]

[exorcet]

when you have a wing as big as the raptor the fuselage is encompassed in the reference area, and I only ever state wing sweep, I am not nit picking about which angle. A square wing with same span and area would give GREAT lift dues to no taper or sweep, that is why an A-10 turns so well. besides, no one thing "tells you everything" that is why I covered three issues and came up with a result that I did not know.

I never meant to imply that you didn’t know that nothing tells you everything, sorry. Lack of taper is usually bad, it’s the lack of sweep that benefits the square wing. Anyway, in an attempt to wrap this up from my end without any more confusion:
Going by definition of aspect ratio, you’re correct that the F-16 has a better figure. However, at the speeds that fighters tend to fly at, and with the usual characteristics of fighter wings (sweep), your analysis loses a bit of accuracy.
The lift slope of a wing is proportional to cosine(half chord sweep angle) [approximated]. And the drag starts to go up sharply at a certain high subsonic mach number depending on LE sweep angle [among other things]. It’s because of this that I don’t really agree that the F-16 must have the edge. To be fair, you just ran the numbers and expanded on them. I’m just providing a counter point. When you posted the actual numbers, you did make me rethink my original post. I didn’t think the AR’s of the planes were that far apart, but actually looking at photos, it makes sense.

Exec, at airshows they tend to show off BEST turn rate. They want to show what the jet is capable of and they often announce it as the "minimum radius turn". Believe me I know all about how speed changes the turn, but the first post of the thread was questioning if the Viper had a faster sustained turn, and based on demonstrated performance it does at sea level, but I already stated that the Raptor is designed for supercruise first.

The problem there is that the F-22’s best anything is probably classified, and may or may not be shown. There is also weapons[probably not an air show issue]/fuel[certainly an air show issue] load to consider and atmospheric conditions.

I must admit though, that since the F-22 is designed for high speed/alt flight, they may not care about low speed sea level performance leaking, though they’ve never announced such information either.

There's clearly shown how much time takes to complete the full 360 degree turn.

I agree with that sentence, but still stand by my last post. They do a 360 turn, but is it the “best” one? You can’t tell. There is some supporting logic from sprstdlyscottsmn’s statement about showing off the best at airshows, but does it apply to something classified like the F-22?

[exec]

.
Exec, at airshows they tend to show off BEST turn rate. They want to show what the jet is capable of and they often announce it as the "minimum radius turn".

But minimum radius turn doesn’t mean ‘best turn rate turn’! Actually tight turn might be quite slow.

I also think that they’re not showing us real minimum radius turn. Look at that ‘airshow turns’ – Raptor doing those ‘tight turns’ almost doesn’t lose speed(STR?). When you want to do the quickest turn you’ll lose a lot of speed(ITR). And if you have TVC you can make your aircraft turn almost instantaneously at low speeds.

So I really don’t think that you can judge aircraft performance by just looking at airshow tricks.

[sprstdlyscottsmn]

When they do the 360 degree turns at an airshow it is minimum radius sustained or maximum rate sustained. If you noticeit takes 18-21 seconds for either plane to do a sustained, level, circle, but it takes the Raptor 11.5 seconds to do a TVC loop in which he sacrifices a couple hundred knots to increase pitch rate. Even the Viper demonstrates nearly 30 degrees per second in a pitch up to vertical climb, because they are not trying to sustain at that point.

[exec]

I know, BUT: minimum radius turn doesn't mean max sustained turn rate! You often get bigger STR at higher speeds, but this often means larger radius of that turn.

For example: MiG-29 has best STR at ~750km/h and can do 360* in 18,5sec and turn radius ~600m.
But the MiG-29’s tightest turn is at ~500km/h - 360*, radius ~400m, but in 22,5sec.

[sprstdlyscottsmn]

I know, I didnt say they were the same, I said it is one or the other at airshows.

[avon1944]

Back on 17, 2005 12:19 PM, an F-16C aggressor pilot "VprWz1" wrote this posting about his encounter with an F-22A, URL;
http://www.f-16.net/index.php?name=PNph ... bc383fa95f

While I haven't been here long - it's not because I haven't been reading the links. I've enjoy red this discussion and I have to jump in and say that the Raptor is amazing.
I'm a Viper driver and I've had the opportunity to fight one (well, a couple really.) Without going where I can't go, I have to say that the Raptor beat up on me, my formation, the Eagles, and the other red air without me ever seeing him until he rolled in on my 6 and gunned the tar out of me. Wasn't much I could do about it! I have fought many other jets in the world - Eagles, Hornets, Hogs (for what that's worth), MiGs, Mirages (2000 & F1), and several other types & nationalities I'm forgetting about I'm sure - I have lost some, but won most fights. The Raptor changed the way I thought about fighting - I have never felt so defenseless before, I'm just glad I am on their side.
The earlier posts about it not being about the Raptor's maneuverability are right on -between how high, fast, and how amazing his technology was we (the many red air) were dead about as fast as the controller could pass the words. I am used to a rhythm in air-air engagements and they just destroyed the tempo - their tune was over before we had really even started.
The bottom line: I was a skeptic and thought it should be done away and replaced with new Bl #60 Vipers - now . . . well, to repeat myself, I'm just glad I'm on their side. Now can I have one too? If not, then I'd be happy to jump on the second line in a new Bl60 or F-35.
Oh yeah, it is a hell of a lot more maneuverable than a Viper. -Cheers

[mx1]

Do they do the F-22s 28 degree per second turn on Raptor demos? If not, does anyone have any links on an F-22 making a 28degree per second turn. Ive been puzzled for quite a while now on why the Raptors minimum radius turn seems to take longer and has a bigger circle than the F-16s MRT.

cheers

[izardofwoz]

Maybe I can help, Patriot & MX1 (if still reading this):

I've seen the F-22 do its thing at airshows twice now, and both times in the routine the jet did it's max performance (rate, radius, G, whatever) turn and went, immediately upon completion of the 360th degree, to the vertical. Then the jet does one of those stop-in-mid-air pauses after coming out of afterburner, floats there for a second, drops its nose and shoots away.
I assume that the Raptor was carrying a bit more energy through the turn than the F-16 does at a comparable place in its demo, because the F-22 pitches up right exactly where it stared the turn..no room at all to pick up any more speed. It's hugely impressive, by the way. All the more so as one gets the distinct impression that the Raptor still has plenty of smash after pointing vertical, and doesn't seem like it really needs to stop and do that tail slide thingy.
An F-16, good as it is conserving energy through turns, would almost certainly need quite a larger turning circle if it wanted to follow the F-22's routine. Conversely, of course, the F-22 mayhaps make a tighter-radius/faster turning circle at a lower airspeed, if it wanted to.

Cheers,

-N

[sprstdlyscottsmn]

I've seen viper go into a vertical climb immediately after the 360 too.

[izardofwoz]

Well, dammit. Never mind, then.

Cheers