F35 debate thread- enter at your own risk.

[haavarla]

Nonsense to stay factual

The F-35 retains full control well beyond 20 AoA as the spec is to remain in control at 50 AoA, not just "coasting" at 50. You do not need TVC to have a high AoA as the YF-23 showed. You just need large control surfaces and a good FCS.

If you have a credible source that says otherwise, feel free to post it.

Between the G-limiter and all the input/output limitation of an modern FCS, there is no way in hell the F-35 can enter 50 deg AoA.
The pilot would have to disengage or overide some software, just like the Flanker when its doing those crazy post stall AoA manuveres.
On older Flankers(Su-27PD, without TVC), this was done by flicking two serperate switches.

Thought this was comon knowledge..
Spud you will have to eat those words shortly.

You can be sure that the F-35 test in high AoA are doing just that, for the purpose of exploring the high AoA handeling of the thing..
Oh and everybody remember that colonel Fornoff statement.. " the F-22 can reach up to 28 deg AoA".
Does this ring a bell?

[SpudmanWP]

"no way in hell the F-35 can enter 50 deg AoA"

It just did. There was not need to disengage anything. The F-35 is designed to go up to 50 AoA under normal operations. Why is that so hard to understand?

[Sens]

Nonsense to stay factual

The F-35 retains full control well beyond 20 AoA as the spec is to remain in control at 50 AoA, not just "coasting" at 50. You do not need TVC to have a high AoA as the YF-23 showed. You just need large control surfaces and a good FCS.

If you have a credible source that says otherwise, feel free to post it.

Such flights are made to verify that characteristic of the F-35 not to depart from controlled flight, when pushed behind the operational limits. Going behind the 20s in AoA you slow down considerably when the drag wins over the lift from doing so. During testing the F/A-18 was flown to a peak of +82-deg, which by the way encountered mild buffeting from 11 deg AoA and started rising with higher AoAs. By that for all FBW-fighters the typical AoA limits range from 22-28 deg AoA for carefree handling. Going behind that the software can no longer safe the ass of every pilot always.

[haavarla]

"no way in hell the F-35 can enter 50 deg AoA"

It just did. There was not need to disengage anything. The F-35 is designed to go up to 50 AoA under normal operations. Why is that so hard to understand?

Clueless of how a modern FCS work and aerodynamic limitation are we..?

Why don't you produce any sources from LM if you like that state, 50 deg under normal flight mode?

One of Colonel Fornoff blunders was to sing about F-22 max AoA at 28 deg, when FCS is in normal flight mode.

http://www.youtube.com/watch?v=WKEa-R37PeU

http://www.youtube.com/watch?v=QfXBo...eature=related

Holly molly! the F-35 can out turn the F-22 in AoA!!!

[mack8]

50 degrees AOA? Meh, Su-35 can do 360. And probably the same for PAK-FA.

[SpudmanWP]

Controllability at 50 is right there in the presser

F-35A test aircraft are limited to AOAs of 20 degrees until their controllability is proven at a higher AOA limit of 50 degrees.

In other words, they are designed to be controllable up to 50 AoA.

[haavarla]

omg..
That F-35 in that vid is practically falling out of the sky at a very slow speed.
Yes possible at 50 deg AoA, in controlled flight.

Now imagine the F-35 doing 500kn, and the pilot jerk the the flight stick hard back.. now how do you think this will play out?

1. Will the FCS(G-limiter) prohibit the F-35 too exceed more than 20-30 deg AoA and save the jet from any structural damage.

2. Or will it hit 50 deg of AoA, and the pilot would have his breakfast in his breathing mask, and the jet has sustained damage, probably some control surfaces missing.

[TooCool_12f]

considering that at 50° AoA you only have vortexes around your wings, you produce, basically, drag, and ... er... drag.... and a lot of it... while your aircraft doesn't necessarily fall like a brick (thanks to the huuuge thrust at the rear end), it can probably control its roll (meaning, avoid falling to one side) by differential moving of the tail surfaces

Trying to do anything else than straight line would result in a serious loss of altitude (considering that even a simple roll as visible in various videos they posted, results in a significant drop)

In this case, "remain controllable" seems more to be "doesn't fall immediately out of the sky". In any case, for "hopsalot": about rafale's limitation to 29°, during flight tests, it went up to 100° without loss of control, however, besides loosing all its speed, the use for such insane angles is non existent.., which is why the FCS was limited to "useful angles", pure and simple

[djcross]

50° AOA is not a big deal.
F-22 was tested at 60° AOA. Watch the linked video and you will see TV was not used -- only aero controls.
http://www.youtube.com/watch?v=cZGEMJxR_FM

[Sign]

The Gripen achieved the AoA of more than 100 degrees during the flight test, but due to the reason for flight safety, the normal setting of the upper limit of the AoA for the Gripen?s FCS is 50 degrees now.

This is probably made on gripen A.

[hopsalot]

Clueless of how a modern FCS work and aerodynamic limitation are we..?

Why don't you produce any sources from LM if you like that state, 50 deg under normal flight mode?

Once again, it is kind of cute in a way watching people here just refuse to believe something they don't like.

Why not google a topic rather than just spouting off in ignorance?

The
F-35A flight sciences tested evaluated handling
characteristics and performance in a larger, more stressful
flight envelope than the other two variants (e.g. up to 20
degrees angle‑of‑attack, with 50 degrees being the required
maximum, and 9 g-load factor, which is the planned
maximum load factor).

http://www.dote.osd.mil/pub/reports/...2011f35jsf.pdf

The aircraft started high AOA testing back in October after it finished engine air start testing. The F-35 has an angle-of-attack limit of 50 degrees, but a source familiar with the design says it could potentially exceed that.

http://www.flightglobal.com/blogs/th...medium=twitter

Both versions of the jet will have an angle-of-attack limit of 50 degrees, which is comparable to the Boeing F/A-18. But while the F/A-18s top out at about 50 degrees AOA--though with some effort one can momentarily exceed that--the Hornet/Super Hornet doesn't have an alpha limiter. Neither does Lockheed Martin's other 5th generation fighter, the F-22 Raptor.

http://www.flightglobal.com/blogs/th...-air-star.html

They'll be going from the current 20 degree AOA restriction to 50 degrees AOA. But unlike its Lockheed Martin corporate sibling, the F-22 Raptor, or the Boeing F/A-18, the F-35 has an alpha limiter that won't allow you to exceed 50 degrees AOA.

http://www.flightglobal.com/blogs/th...start-f-3.html


Seriously people. If you don't understand something ask questions rather than just inventing the answers you wish were true.

[mack8]

Care to enlighten us how is the F-35 going to use this "magical" and "astonishing" 50 degrees AOA in a real world scenario?

[Peregrinefalcon]

One of Colonel Fornoff blunders was to sing about F-22 max AoA at 28 deg, when FCS is in normal flight mode.

http://www.youtube.com/watch?v=WKEa-R37PeU

http://www.youtube.com/watch?v=QfXBo...eature=related

Holly molly! the F-35 can out turn the F-22 in AoA!!!

I have to correct you a bit

Colonel Fornoff is talking about °/s and not about max AoA. In other words F-22 is pulling 28°/s sustained turn at 20000ft (which is very hard to believe )
Doing 28°/s is not the same as flying at 28° AoA. For example, ~15° is the maximum AoA at which F-16 can load to 9G but if he flies at corner speed he will have more than 21°/s sustained turn rate at lower altitudes.

[hopsalot]

Care to enlighten us how is the F-35 going to use this "magical" and "astonishing" 50 degrees AOA in a real world scenario?

Magical? Astonishing?

Did someone here use those words?

No?

From earlier in this same thread:

It isn't likely that an F-35 will actually reach 50 AoA during any real world scenario but it does show once again that the F-35 is anything but the slow, unmaneuverable aircraft critics wish it were.

Super high AoA capability is not particularly useful, in that it is similar to the various air-show maneuvers that some designs have produced.

It is nonetheless noteworthy that the F-35 has an exceptional high AoA capability as it debunks many of the smears critics have invented about the F-35. (That it is unmaneuverable, or helpless in a dogfight, a newer F-105, etc etc.)

In real world operations the F-35 will be unlikely to reach 50 degrees AoA, but the fact that it can go there if needed means that the airframe is perfectly comfortable operating at the 25-30 degree limits of most of its competitors.

I already stated that the 50 degree angle of attack limit would be unlikely to be put to use in real world operations, but it nonetheless exists and I don't like to see the clueless types here spewing misinformation.

There isn't anything "magical" about the F-35's ability to hit 50 degrees AoA, and if you find that "astonishing" you haven't been paying attention to the program thus far.

[Peregrinefalcon]

50° AOA is not a big deal.
F-22 was tested at 60° AOA. Watch the linked video and you will see TV was not used -- only aero controls.
http://www.youtube.com/watch?v=cZGEMJxR_FM

You know that for a fact or you can see from the video that F-22 is not using TVC?

[LmRaptor]

haavarla, Fornoff was talking about the F-22s sustained turn rate rather than its AoA.

The F-22 has actually been tested at over 70 deg of sustained and controllable AoA.

mack8, 360 deg AoA is geometrically impossible.

[mack8]

but it nonetheless exists and I don't like to see the clueless types here spewing misinformation.

Hmm...may i respectfully ask for your credential for claiming such? Do you work in the F-35 programme by any chance ?

mack8, 360 deg AoA is geometrically impossible.

Doesn't seem that impossible when you see a Flanker doing those crazy back-flips.

[djcross]

You know that for a fact or you can see from the video that F-22 is not using TVC?

Watch the direction of travel and velocity of exhaust condensation. It is obvious the engines are at idle. Idle engines cannot produce the control moments needed to overcome the interia of a 50K lb airplane. Also, F-22's control laws do not allow the engines to operate differentially because the moment arm from the centerline is very small and tolerances are tight in torsion due to differential thrust.

At the same time, you can see the huge horizontal tails at work.

[TooCool_12f]

in fact, 360° AoA is 0° AoA (pretty much going ballistic... )

[Sens]

Controllability at 50 is right there in the presser

In other words, they are designed to be controllable up to 50 AoA.

The correct interpretation maybe - the F-35s will be freed to operate carefree in the twenties at least. For that demand the testing of the real limits has started. Whatever behavior will be shown there a carefree handling above the twenties hit some aerodynamic limitations. Several fighters show some contrability behind the 20s, but that is no longer the demanded carefree behavior. By the way other limitations like G-force were reached in the 20s too and the FBW has to take a limiting control already to keep the fighter in safe control.

http://ftp.rta.nato.int/public//PubF...051-PSF-32.pdf

Here everyone can read about the flight control design of the F-18E and what safety measures were introduced for AoAs behind 22.

[SpudmanWP]

http://www.af.mil/news/story.asp?id=123327144

11/20/2012 - EDWARDS AIR FORCE BASE, Calif. (AFNS) -- The Joint Strike Fighter began the integration phase of weapons testing Oct. 26, when the F-35A Conventional Takeoff and Landing aircraft successfully completed the first in-flight test with an AIM-120 Advanced Medium Range Air-to-Air Missile.


It was the first time a weapon communicated with the aircraft during flight using a data link.


Starting in February and continuing through the end of April, the team is anticipating releasing roughly two weapons per week, said Cregier.

Much More at the jump

btw, That is 20-24 weapon drops before the end of April 2013.

[hopsalot]

Doesn't seem that impossible when you see a Flanker doing those crazy back-flips.

Go look up what AoA means...

After that you can start worrying about who is or isn't clueless.

[Peregrinefalcon]

I already stated that the 50 degree angle of attack limit would be unlikely to be put to use in real world operations, but it nonetheless exists and I don't like to see the clueless types here spewing misinformation.

There isn't anything "magical" about the F-35's ability to hit 50 degrees AoA, and if you find that "astonishing" you haven't been paying attention to the program thus far.

As a matter of fact, high AoA handling can give you great advantage in the low airspeed, high AoA arena.

[LmRaptor]

i.e. straight and level flight assuming the chord line is in line with the horizon

[hopsalot]

The correct interpretation is the F-35s will be freed to operate in the twenties carefree. For that demand the testing of the limits has started. Whatever behavior will be shown a carefree handling above the twenties hit aerodynamic limitations. Several fighters show a contrability behind the 20s, but that is no longer the demanded carefree behavior. By the way other limitations like G-force were reached in the 20s too and the FBW has to take a limiting control already to keep the fighter in safe control.

The G-force an aircraft is experiencing is not dependent solely on AoA. You should know that.

You could pull 9 Gs at 20 AoA and 9Gs at 15 AoA, or 30 AoA ...

The F-35 is designed to be controllable at 50 degrees AoA, though the utility of this is relatively limited, it will be a capability of the F-35 nonetheless.

This really shouldn't be such a difficult idea to wrap your head around. The F-35 is not the first aircraft with the ability to operate at these sorts of AoA, even if it is uncommon.

[TooCool_12f]

@ djcross

on that video, when raptor's engines are at idle, it is basically dropping... descending, falling, call it the way you like... while one may consider it as "high AoA flying", it's more like a controlled stall...

[mack8]

Go look up what AoA means...

After that you can start worrying about who is or isn't clueless.

Why aren't you kind to answer to my question about your credentials ?

[hopsalot]

Why aren't you kind to answer to my question about your credentials ?

Because it is simply completely unnecessary and would prove more a distraction than anything else.

I have provided more than ample evidence for each point I have made. If I rattled off a resume all that would do is provoke the usual cries of disbelief or ever increasing demands for proof.

[djcross]

@ djcross

when raptor's engines are at idle, it is basically dropping... descending, falling, call it the way you like... while one may consider it as "high AoA flying", it's more like a controlled stall...

Correct. High AOA testing is done at idle and relatively low airspeed. If the airspeed was faster, the structural G limit would be exceeded and the wings would break off. The purpose of high AOA testing is to demonstrate care-free handing is a post-stall environment. This gives operational pilots the confidence to take their airplanes to the edges of the flight envelope without fear of losing control.

[mack8]

Because it is simply completely unnecessary and would prove more a distraction than anything else.

I have provided more than ample evidence for each point I have made. If I rattled off a resume all that would do is provoke the usual cries of disbelief or ever increasing demands for proof.

Give it a try.