F-35 Flies Against F-16 In Basic Fighter Maneuvers

[zenith]

The F-35 Joint Strike Fighter has been flown in air-to-air combat maneuvers against F-16s for the first time and, based on the results of these and earlier flight-envelope evaluations, test pilots say the aircraft can be cleared for greater agility as a growth option.

http://aviationweek.com/defense/f-35-fl ... -maneuvers

[zenith]

[zenith]

Highlights:

F-35 had the first dogfight (test) in January, no limitation was set.

F-35 flown
9g+ and -3g,
110 deg. AOA.
1.6 Mach
50000 ft. altitude

Pilot really like maneuverability.

It took F-22 3~4 months to get max alpha, 4 days for F-35.

TRO issue is gone.

[zenith]

F-35 Tested Against F-16 In Basic Fighter Maneuvers

Guy Norris and Amy Butler Avialion Week & Space Technology Apr 2, 2015

The F-35 Joint Strike Fighter has been flown :in air-to-air combat maneuvers against F-16s for the first time and, based on the results of these and earlier flight-envelope evaluations, test pilots say the aircraft can be cleared for greater agility as a growth option.

Although the F-35 is designed primarily for attack rather than air combat, U.S. Air Force and Lockheed Martin test pilots say the availability of potential margin for additional maneuverability is a testament to the aircraft's recently proven overall handling qualities and basic flying performance. "The door is open to provide a little more maneuverability," says Lockheed Martin F-35 site lead test pilot David "Doc" Nelson.

The operational maneuvers were flown by Nelson in AF-2, the primary Flight Sciences loads and flutter evaluation aircraft, and one of nine F-35s used by the Edwards AFB-based 412th Test wing for developmental testing (DT). The F-35 Integrated Test Force at Edwards has six F-35As, two F-35Bs and a single F-35C dedicated to DT work, as well as a further set of aircraft allotted to the Joint Operational Test Team. Work is underway as part of efforts to clear the final system development and demonstration (SDD) maneuvering envelopes on the way to initial operational capability (IOC). The U.S. Marine Corps F-35B IOC is targeted for later this year, the Air Force's F-35A in 2016, and the U.S. Navy's F-35C in 2019.

"When we did the first dogfight in January, they said, 'you have no limits,"' says Nelson. "It was loads monitoring, so they could tell if we ever broke something. It was a confidence builder for the rest of the fleet because there is no real difference structurally between AF-2 and the rest of the airplanes." AF-2 was the first F-35 to be flown to 9g+ and -3g, and to roll at design-load factor. The aircraft, which was also the first Joint Strike Fighter to be intentionally flown in significant airframe buffet at all angles of attack, was calibrated for inflight loads measurements prior to ferrying to Edwards in 2010.

The operational maneuver tests were conducted to see "how it would look like against an F-16 in the airspace," says Col. Rod "Trash" Cregier, F-35 program director. "It was an early look at any control laws that may need to be tweaked to enable it to fly better in future. You can definitely tweak it-that's the option."

"Pilots really like maneuverability, and the fact that the aircraft recovers so well from a departure allows us to say [to the designers of the flight control system laws], 'you don't have to clamp down so tight,'" says Nelson. Departure resistance was proven during high angle-of-attack (AOA) testing, which began in late 2012 with the aircraft pushing the nose to its production AOA limit of 50 deg. Subsequent AOA testing has pushed the aircraft beyond both the positive and negative maximum command limits, including intentionally putting the aircraft out of control in several configurations ranging from "clean" wings to tests with open weapons-bay doors. Testing eventually pushed the F-35 to a maximum of 110 deg. AOA.

An "aggressive and unique" approach has been taken to the high AOA, or "high alpha" testing, says Nelson. "Normally, test programs will inch up on max alpha, and on the F-22 it took us 3-4 months to get to max alpha. On this jet, we did it in four days. We put a spin chute on the back, which is normal for this sort of program, and then we put the airplane out of control and took our hands off the controls to see if it came back. We actually tweaked the flight control system with an onboard flight test aid to allow it to go out of control, because it wouldn't by itself. Then we drove the center of gravity back and made it the worst-case configuration on the outside with weapons bay doors and put the aircraft in a spin." The aircraft has been put into spins with yaw rates up to 60 deg./ sec., equal to a complete turn every 6 sec. "That's pretty good. But we paddled off the flight-test aid and it recovered instantly," he says.

Pilots also tested the ability of the F-35 to recover from a deep-stall in which it was pushed beyond the maximum AoA command limit by activating a manual pitch limiter (MPL) override similar to the alpha limiter in the F-16. "It's not something an operational pilot would do, but the angle of attack went back and, with the center of gravity way back aft, it would not pitch over, but it would pitch up. So it got stuck at 60 or 70 deg. alpha, and it was as happy as could be. There was no pitching moment to worry about, and as soon as I let go of the MPL, it would come out," Nelson says.

Following consistent recoveries, the test team opted to remove the spin chute for the rest of the test program. "The airplane, with no spin chute, had demonstrated the ability to recover from the worst-case departure, so we felt very confident, and that has been proven over months of high alpha testing," says Nelson. "It also satisfied those at the Joint Program Office who said spin chute on the back is not production-representative and produces aerodynamic qualities that are not right." Although there are additional test points ahead where the spin chute is scheduled to be reattached for departure resistance with various weapons loads, the test team is considering running through the points without it.

With the full flight envelope now opened to an altitude of 50,000 ft., speeds of Mach 1.6/700 KCAS and loads of 9g, test pilots also say improvements to the flight control system have rendered the transonic roll-off (TRO) issue tactically irrelevant. Highlighted as a "program concern" in the Defense Department's Director of Operational Test and Evaluation (DOT&E) 2014 report, initial flight tests showed that all three F-35 variants experienced some form of wing drop in high-speed turns associated with asymmetrical movements of shock waves. However, TRO "has evolved into a non-factor," says Nelson, who likens the effect to a momentary "tug" on one shoulder harness. "You have to pull high-g to even find it." The roll-off phenomena exhibits itself as "less than 10 deg./sec. for a fraction of a second. We have been looking for a task it affects and we can't find one."

[spazsinbad]

Nadir wants to make a splash - earlier brungitback posted same info:

viewtopic.php?f=22&t=15013&p=288512&hilit=paywall#p288512

[mikemag]

Greetings all. Long time reader, first time poster. Big F-35 fan! Which is why I was a little disappointed to read that article. I might be trying too hard to read between the lines, but it sounds like they're saying "We had an F-35 dogfight a viper. Rather than tell you whether or not it held its own, we're going to reassure you that we can improve it's maneuverability in the future." It sounds like stubby got smoked.

[jdrush]

I've been seeing this happen from work. I have to admit its cool to see contrails/g-trails tangle from the ground

[bring_it_on]

Greetings all. Long time reader, first time poster. Big F-35 fan! Which is why I was a little disappointed to read that article. I might be trying too hard to read between the lines, but it sounds like they're saying "We had an F-35 dogfight a viper. Rather than tell you whether or not it held its own, we're going to reassure you that we can improve it's maneuverability in the future." It sounds like stubby got smoked.

Flight testing routinely provides feedback to the designers of both hardware and the control laws as to what sort of performance is actually achieved and how that can be bettered. Reading it, one realizes that the recommendations to open up the laws a tad bit actually comes from the excellent departure and AOA testing in general where according to the pilot who conducted the test flights the aircraft handled brilliantly. Apart from the first few lines that mentions that they have started to send it up against F-16's in BFM there is absolutely no mention of that in the article. They essentially interviewed the guy who did most of the testing on AF2 and took his feedback as to what he thinks of the performance and what recommendations he had for the designers.

[zero-one]

Greetings all. Long time reader, first time poster. Big F-35 fan! Which is why I was a little disappointed to read that article. I might be trying too hard to read between the lines, but it sounds like they're saying "We had an F-35 dogfight a viper. Rather than tell you whether or not it held its own, we're going to reassure you that we can improve it's maneuverability in the future." It sounds like stubby got smoked.

Or you can take it this way

"We sent AF-2 against F-16s, we were cleared for 9Gs/-3Gs just like the F-16.

I don't want to talk trash against any plane so Im not gona say who won, besides a lot of that depends on the pilot anyway

however what I can say is that the thing flew so well at high AOA which is one of the aircraft's main strengths in a dog fight,

not surprising since we flew the thing at 110 degrees AOA and it was fine, it was happy at 70 AOA, there is certainly an option to add even more agility since the aircraft handles exceptionally against departure. the F-16 on the other hand is limited to 25 degrees AOA.

So you do the math

[mikemag]

The high AOA performance is great to hear of course and in a situation where both planes end up at low speed, I'd expect the F-35's nose-pointing ability to win the engagement. I suppose once I read the title of the article I thought we were going to hear something to the effect that when both planes were lightly loaded the F-35 was able to hold high G maneuvers on par with a late model viper. I'm hopeful we'll still get that type of confirmation from a source other than the LM spokesperson.

[zero-one]

The high AOA performance is great to hear of course and in a situation where both planes end up at low speed, I'd expect the F-35's nose-pointing ability to win the engagement. I suppose once I read the title of the article I thought we were going to hear something to the effect that when both planes were lightly loaded the F-35 was able to hold high G maneuvers on par with a late model viper. I'm hopeful we'll still get that type of confirmation from a source other than the LM spokesperson.

I was hoping for the same thing, but this is what he said, and probably this is what he used to win the engagement,
modern dogfights are usually point and shoot engagements where high AOA and pitch authority is essential,

maybe Doc Nelson didn''t need to turn for very long periods.

Dogfight may have went down like this,

AF-2 and F-16 went into a classic merge, F-16 starts pulling Gs,
AF-2 pulls a high AOA, and points it's nose on the Viper, gets good tone, Fox-2

for Doc Nelson, AOA was the hero of the Day so he wants more of it.

maybe when they get down to guns only, we'll here more about high-Gs

[quicksilver]

The high AOA performance is great to hear of course and in a situation where both planes end up at low speed, I'd expect the F-35's nose-pointing ability to win the engagement. I suppose once I read the title of the article I thought we were going to hear something to the effect that when both planes were lightly loaded the F-35 was able to hold high G maneuvers on par with a late model viper. I'm hopeful we'll still get that type of confirmation from a source other than the LM spokesperson.

Doc Nelson is not "the LM spokesperson." He is a Test Pilot and would jeopardize his credibility with his LM, USG and SETP colleagues (with whom he works every day) if he were to utter anything at odds with the reality. If the Colonel also quoted in the article had disagreed with him, we would have heard about it.

Nose pointing is less relevant in modern BFM than "head pointing" (ie using an HMD to target for high off-boresight missiles). Many aircraft have been doing this for years now.

[jjk]

Doc Nelson is not "the LM spokesperson." He is a Test Pilot and would jeopardize his credibility with his LM, USG and SETP colleagues (with whom he works every day) if he were to utter anything at odds with the reality. If the Colonel also quoted in the article had disagreed with him, we would have heard about it.

I'm a bit lost with the abbreviations, LM = Lockheed Martin, but what does USG and SETP stand for?

[quicksilver]

US Government
Society of Experimental Test Pilots

[jjk]

US Government
Society of Experimental Test Pilots

Thanks, first one i could have guessed (but who are they really ), second one is new for me.

But back to the subject of this thread, i would like to see some videos of these "F-35 against F-16" Maneuvers.