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Bash the F-35 thred.


Belesarius

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One of the technologies that was first flown on the JSF that I fully expect everyone to copy is the new flight control actuator design:

qzqyDoV.gif

 

In the previous generation of aircraft, power for the control surfaces is provided by a hydraulic pump that takes power from the aircraft's engine (or APU) and supplies power to hydraulic actuators at the control surfaces via a series of high-pressure hydraulic lines.

 

MgNdRvq.jpg

 

 

These lines snake all over the aircraft, and there is usually some built-in redundancy in combat aircraft.  No need to repeat the unfortunate experience of the early F-105, which had a single, non-redundant hydraulic line on the bottom of the fuselage.  In combat this was hit with some frequency, which locked up the controls and contributed to the absolutely appalling loss rate of the type in the Vietnam War:

UGkkfPc.png

 

All of these hydraulic lines add up to a lot of messy maintenance:

poLn2FN.png

 

And they also add up to a significant amount of weight.

 

The F-35 is different.

 

In the F-35 there are no hydraulic lines running through the aircraft.  Instead, power is transmitted electrically to high-torque stepper motors that drive hydrostatic motors that drive the flight controls.  The hydraulic component is much smaller and is self-contained.  Instead of blowing out the system to do maintenance, the actuators can simply be unbolted and replaced.  The system is also lighter, as it deletes all of the hydraulic lines running all over the place.

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Good point.  It's hard to separate hydraulic lines very much because they're big and fat and wings need to be streamlined and skinny, and hydraulic lines need to be accessible.  Electrical wires are skinny and almost maintenance-free.  The EHA on the F-35 is clearly better than legacy systems, and another example of how even if the JSF program falls apart or some of the members go their own way, what replaces it will substantially be repackaged F-35 technology.

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Election promises.

http://www.theglobeandmail.com/news/politics/canada-to-stay-in-program-of-f-35-jet-buyers-despite-pledge-to-withdraw/article28897002/

 

Prime Minister Justin Trudeau’s party announced during last year’s election campaign that it “no longer makes sense” to buy a fighter with the F-35’s stealth, first-strike capability, citing skyrocketing costs for a plane that has been plagued with development problems. The Liberals vowed instead to buy a “lower-priced” aircraft and funnel the money saved into the Royal Canadian Navy.

 

This week, however, Department of National Defence spokeswoman Ashley Lemire said Canada plans to pay the latest required annual instalment to the Joint Strike Fighter program. She said the upcoming payment is estimated to be $32.9-million (U.S.)

 

The contribution would maintain Canada’s membership in the F-35 buyers’ pool. This gives Ottawa the right to buy F-35s at a discount and allows Canadian companies to continue to bid on supply contracts for the plane.

 

Asked why Canada remains in the Joint Strike Fighter program when the Liberals have eliminated the plane as an option, Defence Minister Harjit Singh Sajjan said the government is still reviewing how it should proceed on replacing the country’s aging CF-18 fighters.

 

“We can’t just make a very quick decision on something like this. We want to make a responsible decision as we move forward. We have to go through the proper requirements. Once we go through a proper process, decisions will be made at that,” he said.

 

One procurement expert working for the federal government, who spoke on condition of anonymity, said it’s unclear whether Ottawa could successfully defend against legal action should it bar jet maker Lockheed Martin and its F-35 plane from a competition. “They will have to decide whether they want to run a competition or face a lawsuit.… The easiest option for a variety of reasons is to run a competition and run it fairly.”

 

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This is an article from fifteen years ago when the actuator technology was new.

 

Some interesting quotes:

 

 

He adds that it can reduce aircraft weight by as much as 700 pounds (315 kg), but not because the system itself is lighter. "We’re taking weight out of the hydraulic system, weight out of the secondary power system, and out of the thermal management system, because we’re not generating as much heat. "But we’re offsetting it with a relatively more complex actuation system," Eicke adds. "If you don’t do the trade studies at the air vehicle level, you don’t see the benefits.

 

 

 

 

"With the previous hydraulic power system, you were dumping power into the actuator whether you were using it or not," he continues. "All that energy becomes heat–thousands of BTUs–and gets dumped into the fuel system.

"With the new (electro-hydrostatic) actuation systems, if you are not generating any heat, you don’t have to dissipate it. It’s a much cleaner secondary power system. We don’t have to provide a secondary and an emergency source of hydraulic power," says Eicke.

It frees us–gives us more thermal margin, which we can apply to other systems on the aircraft, or we can reduce our thermal management system weight and volume to compensate for that, making our aircraft smaller, lighter and cheaper."

 

So the system itself isn't any lighter, but it seems to reduce weight secondarily.  And apparently this weight savings can offset having more powered control surfaces on the aircraft.

 

Does the PAK-FA have EHAs, I wonder?  The Russians love putting control surfaces on absolutely everything:

qyJvDzT.jpg

It might help reduce the maintenance problems of this approach if they did use EHAs.

 

 

 

 

The J/IST program was intended to reduce the risk of certain new technologies chosen as candidates for the JSF program. The Air Force’s Advanced Fighter Technology Integration (AFTI) F-16 demonstrator aircraft made its first flight with the power-by-wire subsystems package last Oct. 24. Since then, flight control effectiveness has been demonstrated during mach 1.3 supersonic flight. The aircraft performed flying quality maneuvers while supersonic, including 5-g turns, pitch, roll and yaw "doublets" and sideslips. The tests also included low-altitude strike missions and the chance for the Lockheed Martin team to study the actuator and generator subsystems’ thermal behavior. 

 

 

Interesting how the F-16 AFTI rounded out its career.

jqEVITQ.jpg

 

This is a more recent article on the things that have been done to make the F-35 more maintenance friendly.

 

 

Paramore: On a F-16, for example, all your actuators are still hard-lined into the hydraulic system.  The actuators on the F-35 are fully self-contained:  four cannon plugs, some bolts, and it pops right out after you take your panels off.

On the F-16, you’d be four cannon plugs, eight bolts, two hydraulic lines, refuel or resetting the hydraulic systems, re-servicing those, bleeding and leaking them, and then doing the ops checks, not to mention if you had some kind of rigging you had to do for the actual actuator if it wasn’t just a straight swap, you’d had to go in and do all your rigging for that actuator.  The F-35 system self-adjusts the flight controls, so once you go in and replace an actuator, you run auto-rig, and the system auto-rigs the actuator.

Cool, so not only are the actuators easier to replace, getting them harmonized with the flight controls is easier too.

 

 

The endgame for the F-35 is for the aircraft to report back to the ground before it ever comes back. Let us go back to our actuator as an example.  If you have a hydraulic actuator that’s starting to need replacement, let’s say the fluid level starts to deplete for any reason whatsoever, the system will detect that trend, report it back to the ground, and through that reporting, you start looking at the electronic data, you can determine when that EHA will have to be replaced. You can also have the CMMS system, and the PBL (Performance Based Logistics) system; identify a need to get one shipped to the site for replacement on that airplane.

 

 

Very slick, very streamlined.  The aircraft's parts report any problems to a computer on the aircraft, and then that information gets forwarded to the base and thence to the supply chain.  I'm liking what I hear.

 

 

So we have an HRC, which is a Health Reporting Code for a system.  And, for example, if an actuator sends out its HRC code and says, “I have this problem,” then when we pull that into the CMMS system, when the AFRS solution sets are built, that’s kind of like your old troubleshooting tree you were talking about.  It’s all electronic.

 

The system will say you have a HRC.  And the system will suggest you start with this AFRS solution set No. 1.  And you go through the tree to troubleshoot it.  It will then ask you, “did this fix your problem?” And if you click on “no,” then it says, okay; let’s try this solution set.  And you go down through it, and if it says, did this fix your problem; you go “yes.”

 

Now you’ve done two things.  You’ve not only gone through a troubleshooting tree electronically that you otherwise had to do with paper in the past, you’ve also started to solidify the data in the system because you told the system via feedback.  Yes, this fixed my problem.

 

 

And there's a machine-learning system that helps ground personnel troubleshoot common issues.  Also slick and potentially quite good.

 

 

Paramore: It is analogous to the shift of going from Windows to Macs.  And if you fail to open your mind, you’ll fail the transition.  Because, you know, everybody is used to their little PC running Windows, doing it the way they’ve always done it, the way they always want to do it.

 

It is more like Apple than Windows.  Windows shifts through a series of new systems, XP to Vista to Windows 7. Now we’re in an Apple-like world, where you can run 64-bit apps in a true 64 environment and screaming past everybody else.

 

SHIT.  The program is doomed.

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Holy fuck that last bit is a towering edifice of stupid. Remind me to go on a rant about stupid bullshit UI elements that have gone unchanged since the first version of OSX and iOS. Basic things like the dock and the stupid grid of static icons.

 

The only hope is that it's such a giant goddamn tower of dumb that it gets the tower of babel treatment.

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A back-of-the-envelope calculation of the F-35's WVR maneuverability.  This is in line with similar analyses; the F-35's performance isn't stellar when compared to previous generation fighters with no weapons.  When the planes actually have weapons the F-35 pulls ahead thanks to the drag-free* internal weapons carriage.



*basically

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