F-22A versus EF2000

Anything goes, as long as it is about the Lockheed Martin F-22 Raptor
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neurotech

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Unread post23 Nov 2012, 22:32

borntoholdout wrote:The F-22's internal weapons help a little. Having more of your weight close to your center of mass helps all maneuvers. Not just at high speed were the drag advantages kick in.

The F-22's max thrust is classified. "35,000 lbs class". This just my opinion but I bet they're closer than that. :2c:

Its probably been discussed on the forum, but probably less than 40,000 as currently fielded. If the F119 was much higher rated, it would have been put in a F-35, instead of developing a new engine at a cost in the billions. The F135 is not "new fan" on a F119, its derivative engine.

The F-22 is definitely a larger jet. I'd also assume that the MiG-35 will get at least one engine upgrade before real IOC.
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Raptor_claw

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Unread post24 Nov 2012, 01:10

neurotech wrote:
Raptor_claw wrote: ...What TV can do, is create good "instant" nose pointing, but this does not translate into a corresponding increase in turn rate.
Rate or Radius?? MiG-29OVT can "turn" pretty quick, in airshow configuration has sufficient thrust to maintain a very tight turn. http://www.youtube.com/watch?v=WoQ-7Csd ... ure=relmfu is a good demo vid.
Not sure what your question is. For a given speed, if rate is increased then Radius is decreased. I should, however, have used the word "proportional" rather than "corresponding". You can get some improvement to instantaneous rate by increasing AOA (assuming you are starting below corner speed), but it is a case of quickly diminishing returns. Also, not sure what I was supposed to glean, specifically, from the video. Is there something at a specific time?
Raptor_claw wrote:
Aircraft such as the MiG-35 (which is NOT operational) have 2D thrust vectoring. This could enable it to "hover" at high bank angle/low kinetic energy "knife edge" style.
... the vertical component of the total thrust force must act through the c.g. - not feasible with engine exhaust vectoring only, regardless of the number of degrees of freedom.

Your comment about CG is technically correct, Maybe "hover" taking it a bit too far, but the MiG-29OVT can maintain "knife edge" down to a pretty low airspeed, beyond what a F/A-18 would be dropping like a brick, due to a combination of aerodynamic properties at high alpha, AND 2D thrust vectoring.
First, the "knife edge" is not a high alpha maneuver, in fact it is usually a very low (~0 deg) AOA condition. The "lift" during a knife edge does not come directly from vectoring. Rather, the "lift" (actually side force in the aircraft reference frame) is generated from angle of sideslip (AOS). Since most fighter-type configurations are inherently fairly stable in the directional (yaw) axis at low AOA, the rudder (and/or yaw vectoring) are required to generate and maintain sideslip at the level high enough to create a side force equal to the aircraft's weight. For this to happen, the net force from vectoring/rudder is actually in the "wrong" direction (i.e. opposing the net "lift" force from sideslip), so the tv is not directly providing lift. Bigger point is, though, that the lift (from sideslip) is still directly tied to airspeed - so the assumption that a MiG could do a slower knife edge than an F-18 simply because it has yaw vectoring is unfounded. Not to say that isn't the case, but if true it is more a result of the basic aerodynamic characteristics (including vertical tail/rudder sizing), as well as any sideslip command limits that may be built into the flight control system.
The 2D TVC does improve stability in high alpha/high bank angle, beyond the capability of the F-22.
Yes, 2D vectoring does improve overall capability at high alpha, regardless of bank. High alpha/high bank conditions also mean very high rates of descent, though, and are always very transient in nature.
Credit where credit is due, the MiG-29OVT or MiG-35 is a extremely capable jet fighter close in.
Not questioning that, but using any public, airshow-type demonstration to extrapolate to actual in-service use must be done with the realization that the operational jets are not capable of performing all the same manuevers, specifically the very low speed stuff.
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neurotech

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Unread post24 Nov 2012, 01:57

Raptor_claw wrote:
The 2D TVC does improve stability in high alpha/high bank angle, beyond the capability of the F-22.
Yes, 2D vectoring does improve overall capability at high alpha, regardless of bank. High alpha/high bank conditions also mean very high rates of descent, though, and are always very transient in nature.

@Raptor_Claw: Do you actually fly F-22s?

The F/A-18E/F can side-slip or roll at high AoA, and maintains good rudder control and yaw/roll stability as well. This can be done without loosing altitude. To stay within WEZ, these type maneuvers can be performed during a knife fight with a F/A-18E/F, but not older jets like the F/A-18C/D
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Unread post24 Nov 2012, 02:29

I would imagine Raptor_C_law is the reason F-22's "fly".

The pilots are at his mercy. :shock:
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neurotech

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Unread post24 Nov 2012, 03:16

outlaw162 wrote:I would imagine Raptor_C_law is the reason F-22's "fly".

The pilots are at his mercy. :shock:

Like Tom Morgenfeld in the YF-22 87-0701 :D

There is a very few test/evaluation pilots who have flown both the F-22 and the MiG-29

The bottom line is that a F-22 is not invulnerable during a knife fight against a smaller fighter aircraft such as a F-5E/F or the mid-size MiG-29OVT for either a gun kill or an AIM-9 at that has been manually slaved to the target.
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Raptor_claw

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Unread post24 Nov 2012, 03:41

neurotech wrote: Like Tom Morgenfeld in the YF-22 87-0701 :D
If you're interested, you can read my (brief) discussion, almost at the very bottom of page 1:
http://www.f-16.net/f-16_forum_viewtopic-t-6343-postdays-0-postorder-asc.html
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Unread post24 Nov 2012, 04:12

@raptor_claw; Did you work on the FCS "control laws" for the Raptor?
Raptor_claw wrote:
neurotech wrote: Like Tom Morgenfeld in the YF-22 87-0701 :D
If you're interested, you can read my (brief) discussion, almost at the very bottom of page 1:
http://www.f-16.net/f-16_forum_viewtopic-t-6343-postdays-0-postorder-asc.html

Thats pretty close to the version I heard regarding the YF-22 mishap.

We had a unexpected FCS response incident in a F/A-18F during an asymmetric stores test flight, executing a go-around. The jet suddenly rolled, and the pilot over-corrected but then recovered. No damage to the jet, just some explaining to do.
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haavarla

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Unread post26 Nov 2012, 22:24

neurotech wrote:
Credit where credit is due, the MiG-29OVT or MiG-35 is a extremely capable jet fighter close in.


I'm nitpicking here. But the the Mig-29M, fittet with OVT Nozzles is very different in many ways from the proposed Mig-35. The Mig-29M has a different airframe..

The closest to Mig-35 in Russia, is its cousine Mig-29K.
If you remove those CV modification on Mig-29K, then you are left with a Mig-35 airframe.

If there ever comes a Mig-35, it will just as Mig-29K have no OVT or other type of TVC nozzles installed(for obvious reasons).

Instead, both Russian Mig-29K/35 will have increased engine thrust, the RD-33MKM engine version. upgraded RD-33MKM comes with a wet thrust of 9,500 kgf.

http://en.take-off.ru/news/107-june2012 ... tontherise
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disconnectedradical

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Unread post31 Dec 2012, 04:33

Well, regarding the Alaskan BFM exercise, I'm intrigued by Pfeiffer's notes that the Typhoon can out-accelerate and out-climb the F-22. I suppose this has to do with the Typhoon's higher TWR. IIRC, the F-22 was quite a bit heavier than originally anticipated.
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Unread post31 Dec 2012, 14:49

only by about 6 tons or so. Back in the 90s I was reading that the Raptor would weigh roughly 30,000 lbs (with the eagle being 28,000 I thought it was reasonable) and it was going to carry 24,000lbs of gas. I thought to myself "holy smokes this this is awesome!" Now I see from both Lock-Mart and USAF that it weighs ~44,000 lbs and carries ~18,000lbs of fuel. Fairly similar numbers to the F-14D with external tanks. Although, the F-14 never had 840 ft^2 of wing, 70-74,000 lbst, TVC, and a 9 G limit. So weight and fuel are roughly the same but that is where similarities end.
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neurotech

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Unread post31 Dec 2012, 22:14

sprstdlyscottsmn wrote:only by about 6 tons or so. Back in the 90s I was reading that the Raptor would weigh roughly 30,000 lbs (with the eagle being 28,000 I thought it was reasonable) and it was going to carry 24,000lbs of gas. I thought to myself "holy smokes this this is awesome!" Now I see from both Lock-Mart and USAF that it weighs ~44,000 lbs and carries ~18,000lbs of fuel. Fairly similar numbers to the F-14D with external tanks. Although, the F-14 never had 840 ft^2 of wing, 70-74,000 lbst, TVC, and a 9 G limit. So weight and fuel are roughly the same but that is where similarities end.

I'm of the opinion that weight does matter in a fighter jet.

It's basically a cost-benefit trade-off. They could have shaven 5-10k from the weight of a raptor, but it would have driven up the airframe costs even more. The F-35B in particular went through these kind of issues, where cost/weight/structural strength were tweaked during EMD.

A similar argument could be made about the MiG-25 vs YF-12. The MiG-25 didn't have the top speed of a YF-12, but was mass produced, unlike the YF-21/SR-71 family. Exotic jet fighters are great, but if they don't get past EMD/LRIP phase.

I actually think that Boeing has an edge with the F/A-XX program, due to the transfer of technology from the 787, which uses large amount of composites in the airframe. I would even suspect the 787 has more structural composites than the F-35, relative to airframe weight.
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Unread post01 Jan 2013, 01:03

6 tons is no small amount, especially if the technology demonstrator was just 15 tons. I believe much of the weight increase was due to LM's difficulty in incorporating composite materials, since it was pretty new at the time. Like how some of the composite wing spars had to be replaced with titanium ones to pass the ballistic impact requirements. In any case, I think the Typhoon's superior TWR (at full fuel, at least) may have been responsible for some of its victories.

On a side note, I find that the much heavier F-22 has a higher supercruising speed of Mach 1.8 compared to the YF-22's Mach 1.6 to be pretty astounding. Says a lot about the Raptor's aerodynamics.
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neurotech

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Unread post01 Jan 2013, 01:47

disconnectedradical wrote:6 tons is no small amount, especially if the technology demonstrator was just 15 tons. I believe much of the weight increase was due to LM's difficulty in incorporating composite materials, since it was pretty new at the time. Like how some of the composite wing spars had to be replaced with titanium ones to pass the ballistic impact requirements. In any case, I think the Typhoon's superior TWR (at full fuel, at least) may have been responsible for some of its victories.

On a side note, I find that the much heavier F-22 has a higher supercruising speed of Mach 1.8 compared to the YF-22's Mach 1.6 to be pretty astounding. Says a lot about the Raptor's aerodynamics.

Not saying you are wrong, but materials that are in the F-35/787 were not available in the YF-22. Demostrators are not always "weight optimized" either, and can sometimes decrease in structural weight, based on flight testing and EMD optimization.

It's quite possible the FBW control laws were not optimized in the YF-22, which could limit its supercruise and top speed. Again, flight testing resolves these issues.
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Unread post01 Jan 2013, 01:49

Keep in mind that the Typhoon was "slicked off." In combat configuration, the Typhoon's performance would be significantly worse. I'm guessing the Raptor was flying with radar reflectors (they want to keep its radar signature classified). I wonder how an encounter would play out if the Typhoon was carrying drop-tanks and a full combat load out.
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Unread post01 Jan 2013, 01:59

neurotech wrote:
disconnectedradical wrote:6 tons is no small amount, especially if the technology demonstrator was just 15 tons. I believe much of the weight increase was due to LM's difficulty in incorporating composite materials, since it was pretty new at the time. Like how some of the composite wing spars had to be replaced with titanium ones to pass the ballistic impact requirements. In any case, I think the Typhoon's superior TWR (at full fuel, at least) may have been responsible for some of its victories.

On a side note, I find that the much heavier F-22 has a higher supercruising speed of Mach 1.8 compared to the YF-22's Mach 1.6 to be pretty astounding. Says a lot about the Raptor's aerodynamics.

Not saying you are wrong, but materials that are in the F-35/787 were not available in the YF-22. Demostrators are not always "weight optimized" either, and can sometimes decrease in structural weight, based on flight testing and EMD optimization.

It's quite possible the FBW control laws were not optimized in the YF-22, which could limit its supercruise and top speed. Again, flight testing resolves these issues.


YF-22's may not be weight optimized, but I think they're also not required to meet the 8000 hour structural life or ballistic impact requirements that the production aircraft had to meet. In any case, I recall reading somewhere that they weren't able to incorporate as much composites into the production F-22 as they would've liked (mainly due to ballistic impact shortcomings IIRC).

I do think that the F-22's increased weight somewhat hinders its supercruising potential. For a given LD coefficient, more weight means more drag.
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