F-35B/C Lightning II (Joint Strike Fighter)

[squeeze]

I got to fly the F-35 sim up in Ft Worth 2 years ago. WAY easy to fly and hover. However, the Marine Test Pilot (F-18 background) said that Harrier guys hate the logic used in the software.

I got to fly the sim a couple times - once in CP and once in Yuma and I agree. The flight control logic in the jetborne mode is completely backwards IMO.

The way the JSF works is that below a certain airspeed, where your throttle is is defined as a neutral point of sorts. Once established in a hover, moving the throttle from the neutral point moves the jet forward and backward. Moving the stick fore and aft moves the jet up and down. In the Harrier, with your jet fountain supporting you in jetborne flight, the throttle controls your up/down. The stick still controls pitch/roll. It also doesn't build up a rate like the Harrier does. If you push fwd on the stick, the jet goes down. As soon as you let off, it stops descending.

The JSF engineers swear it's "more intuitive" but I argue that it's completely opposite. When I know my engine is supporting me, pulling power to go down makes sense, damnit.

 

[xmid]

Lockheed's magazine "Code One" (dad sends them to me) has a big thing on the differences between the x-35 and the production model f-35. The "X" had two side doors over the fan but the "F" will have one door that hinges aft to "reduce lift fan flow distortion, which increased lift fan performance and operability". The magazine says the F-35 will only be able to carry a maximum of two AIM-120's and two satellite-guided JDAMS because of the size of it's weapon bays... That doesn't seem like much to me, especially when the super hornet was supposedly desined to be able to carry more ordinance than the legacies... Overall there were a ton of things changed from the X-35 and seeing actual pics of the JSF in flight refueling and such makes it worth while to try to get a copy of the magazine.

 

[phrogdriver]

I got to fly the sim a couple times - once in CP and once in Yuma and I agree. The flight control logic in the jetborne mode is completely backwards IMO.

The way the JSF works is that below a certain airspeed, where your throttle is is defined as a neutral point of sorts. Once established in a hover, moving the throttle from the neutral point moves the jet forward and backward. Moving the stick fore and aft moves the jet up and down. In the Harrier, with your jet fountain supporting you in jetborne flight, the throttle controls your up/down. The stick still controls pitch/roll. It also doesn't build up a rate like the Harrier does. If you push fwd on the stick, the jet goes down. As soon as you let off, it stops descending.

The JSF engineers swear it's "more intuitive" but I argue that it's completely opposite. When I know my engine is supporting me, pulling power to go down makes sense, damnit.

I agree, and considering the AV-8B and V-22, our existing V/STOL aircraft, work in a similar fashion, I don't know why they'd change it. More throttle=more power, not "move forward." I know the thrust vectoring isn't used a lot in manuevering flight, but it would also seem that if you were at an intermediate setting, you would be unsure which flight control law was in effect at the time.

 

[MasterBates]

I flew the -35B sim, and I don't like it's control laws.

When in conversion mode it felt like the jet did what it pleased, and I was along for the ride. Any control inputs were treated as "suggestions" at best by the computer. I asked if that was a sim-quirk, and was told "nope, that's how it flies" by the engineers.

 

[Semper Jump Jet]

When in conversion mode it felt like the jet did what it pleased, and I was along for the ride. Any control inputs were treated as "suggestions" at best by the computer. I asked if that was a sim-quirk, and was told "nope, that's how it flies" by the engineers.

So it's like a Hornet?

 

[Flash]

Lockheed's magazine "Code One" (dad sends them to me) has a big thing on the differences between the x-35 and the production model f-35. The "X" had two side doors over the fan but the "F" will have one door that hinges aft to "reduce lift fan flow distortion, which increased lift fan performance and operability". The magazine says the F-35 will only be able to carry a maximum of two AIM-120's and two satellite-guided JDAMS because of the size of it's weapon bays... That doesn't seem like much to me, especially when the super hornet was supposedly desined to be able to carry more ordinance than the legacies... Overall there were a ton of things changed from the X-35 and seeing actual pics of the JSF in flight refueling and such makes it worth while to try to get a copy of the magazine.

There were dueling articles in Proceedings about 5 years ago IIRC that argued the pluses and minuses of the F-35B vs the F-35A/C. The authors were a Hornet guy and a Harrier guy, guess which one argued for which version? They continued their debate in letters after the articles, 'correcting' each other.

One of the biggest contentions was the payload and fuel differences. The F-35B carries 4-5000 pounds less fuel, with the associated range difference, than the F-35A/C and can only carry 2x1000lb bombs or 2 AAMs internally instead of 2x2000lb bombs or 4 AAMs internally.

F-35 Specs: http://www.globalsecurity.org/military/systems/aircraft/f-35-specs.htm

F-35B specs: http://www.lockheedmartin.com/products/f35/f-35specifications/f-35b-stovl-specifications.html

F-35C specs: http://www.lockheedmartin.com/products/f35/f-35specifications/f-35c-cv-specifications.html

 

[vick]

Don't forget, it can carry external stores as well. There has always been a tradeoff for the STOVL capability so the compromise in internal store capacity should not be a surprise. The original argument for the Harrier's reduced payload was that it can be based closer to the fight - how well that has borne true is debateable.

Back in 2001 we were on the Bataan for a couple of weeks for some CQ and A/A training. This was before the -35 contract was awarded and we had a bunch of engineers along with with us from both Boeing and LMT. They were doing final design work on their respective contenders and they wanted to observe VSTOL ops around the boat. After watching us for a while they started pulling us aside and picking our brains individually on all aspects of flying the jet.

We were pretty shocked to learn that they hadn't done this type of interface sooner - like years sooner. They basically expressed that the whole control interface and logic of the Harrier was dicked and they told us not to worry - that they had figured it all out with their respective designs. We in turn expressed that there were elements of the current design that we liked very much (like direct control over the nozzle angle for starters) and did not want to see go. They were shocked to find that we embraced what they judged to be archaic technology. When they began to explain how their systems would work we universally screwed up our faces and expressed the same distaste for the concept that guys who get in the sim now are coming away with.

It was our feeling at the time that if you are going to redesign a system you might START by looking at the current iteration and then making your developments from there. Another classic example of the disconnect between the geek squad and the operators...

 

[Flash]

Don't forget, it can carry external stores as well. There has always been a tradeoff for the STOVL capability so the compromise in internal store capacity should not be a surprise. The original argument for the Harrier's reduced payload was that it can be based closer to the fight - how well that has borne true is debateable.

Same external payload capability, but it still has the shorter range. As for the old argument about being closer to the fight, I am still not buying it.

 

[Cron]

In all seriousness, it sounds to me like they're trying to make the controls function like those in a video game (e.g. Battlefield 2).

...so where do the xbox controllers plug in?

 

[Harrier Dude]

The F-35B sim is actually easy to fly if you think about landing differently.

When I flew it, I had the same issues that other Harrier guys did in V/STOL. If you think like a Harrier (in terms of control inputs) it's all ass backwards. If you think like conventional flying, it's very, very easy.

For instance, if you look at the HPI like a wingtip off your lead, and then fly as if you were doing a crossunder (really half of one), the contol inputs will put you right on the spot.

It's actually very consistant. Pull back on the stick, the jet climbs. Always. Push forward on the throttle, the plane goes forward. Always. Muscle memory will kick in eventually.

As to the forward basing issue and payload concerns, there are two problems with the debate.

First, the Harrier was designed to be based close to enemy lines. That was the concept. Whether or not we ever actually did it, is a matter on considerable argument. Some say DS was it. Some say OIF1 (three rivers) was it. I would say that we never actually used it to the extent that it was designed. Why? It turns out that we never really needed to. The Russians never charged throught the Fulda gap.

Second, you have to think of the F-35 as a 5th generation fighter. Don't use arbitrary "pounds of payload" numbers to compare apples to oranges. It's what you do with it that counts. Of course, as a general rule, more is better. But you have to take into account what it was designed to do.

 

[subTidal]

F-35A flight testing update:

http://www.compositesworld.com/news/f-35a-to-begin-extended-flight-testing.aspx

 

[statesman]

HD,

on the Marine side of things is there any uproar about the F-35 not having a gun? I assume a big part of the F-35B mission will be for CAS, it seems having a gun would be advantageous. As I understand it there is a pod developed to add a gun to the aircraft, but was the lack of a built in gun at all a source of contention?

 

[Harrier Dude]

HD,

on the Marine side of things is there any uproar about the F-35 not having a gun? I assume a big part of the F-35B mission will be for CAS, it seems having a gun would be advantageous. As I understand it there is a pod developed to add a gun to the aircraft, but was the lack of a built in gun at all a source of contention?

Yes. The cry of uproar is led mostly by those that have never even used the gun that they have.

Is it a valuable weapon? Sure. Is it a death blow not to have one? No.

The main argument against the external gun pod is the compromise of stealth and drag. Neither of which is a huge obstacle in a CAS environment.

 

[exo]

The Looming Navy Strike Fighter Gap

Fighter Gap...


http://www.dodbuzz.com/2008/11/11/navy-fighter-gap-which-way-obama/

 

[The Chief]

Fighter Gap...

Well, I think the OTT (Obama Transition Team) would argue that we do not have a fighter gap, rather too many big deck carriers. But at this point we will have to wait and see. Change is on the way.