New Flight Control Improves F-35C Handling Carrier Approach

[spazsinbad]

New Flight Control Mode Improves F-35C Handling on Landing Approach 25 July 2012 by Tamir Eshel
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+ VIDEO:
F-35 New Flight Control Software
http://www.youtube.com/watch?v=jlqRo3oB ... r_embedded

"Published on Jul 24, 2012 by NAVAIRSYSCOM
A F-35 Joint Strike Fighter test pilot discusses new flight control software
to aid in carrier approaches. Video courtesy of Lockheed Martin."
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http://defense-update.com/20120725_new- ... g-approach

"Flying approaches for a carrier landing just might be a little easier in the future. The F-35 Integrated Test Force at Patuxent River completed the first dedicated test flight May 4 to evaluate the F-35C Lightning II Joint Strike Fighter’s approach handling characteristics with new flight control laws. Part of software version 2A the new flight control software, called Integrated Direct Lift Control (IDLC), translates pilot commands into choreographed changes to engine power and control surface movement, greatly improving glide path control, according to one test pilot....

...Pilots typically qualify to land on a carrier by completing around 30 landings while in initial flight training and at their fleet replacement squadrons. “We have to spend a significant amount of training time on carrier landings, especially night landings,” Bibeau said. “To make all the little high-pressure adjustments takes headwork, intellect and reflexes. It’s unforgiving.” But with the new flight control software IDLC in the F-35, Taylor sees “the potential to reduce the training burden for new pilots going to the ship.”...

...Another change to the F-35C is the redesigned tail hook. Lockheed Martin is confident the redesigned tailhook will be ready for the planned carrier flight tests currently scheduled for 2014. The original hook did not perform well and casued the aircraft to miss the arresting cable too often."

Best to read the entire article with extra pilot quotes at source - tah.

[spazsinbad]

F-35C Integrated Direct Lift Control: How It Works 09 Oct 2012 Eric Tegler
IDLC will make carrier approaches easier

"...IDLC’s job is to quickly help the pilot make glide slope adjustments during the carrier approach, Buus explains. It is resident within all three F-35 variants, not just the C model.

“What provides a huge benefit to the pilot is that [IDLC] moves the trailing edge flaps up or down to increase or decrease lift, which gives the airplane a very precise glide path control. It almost feels like a predictive control because it happens so quickly and you can get such effective changes in glide path. The trailing edge flaps are pretty large on the F-35C. For a carrier approach we nominally set them to 15 degrees trailing edge down, which is a half-flap configuration. So there’s room for the flaps to come down and to come up and either increase or decrease lift.”

In essence, one could call IDLC “automatic flap response.” Its effect is to literally “heave” the airplane in the vertical axis, Buus says.

“The F-35C is designed to be an auto-throttle flyer on approach. So the pilot will engage auto-throttles and then he just has to fly glide path and lineup with the stick. When he makes pitch-stick inputs to control the glide slope – if he pulls back on the stick a little – the airplane will respond by lowering the flaps to increase lift. The seat-of-the-pants feel is a lot more in the vertical axis. It actually changes the G-level of the airplane; as the flaps come down, they add lift, increasing G and vice versa.”

The pilot is indirectly flying the flaps with the stick, Buus says. From the cockpit, IDLC gives the F-35C exaggerated throttle/pitch response, the test pilot affirms. “It’s almost immediate. It takes longer to make the correction in legacy airplanes.”

NAVAIR contends that IDLC can potentially shorten the carrier qualification learning curve for new pilots by offering more control during the approach, and Buus agrees.

“The flight control engineers have really done an amazing job. IDLC is just one part of it. It’s an easier airplane to fly behind the ship. The easier the airplane is to fly, the safer it is and the easier to train pilots to fly it well. Over time, I think it will reduce some of the training costs and burden to the Fleet.”

In a few years the F-35C’s flight control system will pair with the Joint Precision Approach and Landing System (JPALS) to enable data-linked approaches controlled from the carrier. IDLC will take relevant incoming data from the flight control computer and aid in making the process that much more precise.

With its larger wing and flaps and control harmony, the F-35C benefits more from IDLC than its sister variants. But they too enjoy more precise approach control with the system, Buus maintains. And he adds that it could be integrated into legacy aircraft such as the F/A-18E/F Super Hornet and EA-18G Growler."

http://www.defensemedianetwork.com/stor ... -it-works/

More or less the whole story here and worthwhile to put this good explanation - complete - here.

[count_to_10]

I'm thinking that when they finally get around to fully automatic, better-than-human carrier landings, it may change the optimum carrier configuration.

[neurotech]

I'm thinking that when they finally get around to fully automatic, better-than-human carrier landings, it may change the optimum carrier configuration.

One of the ready room stories was about a test pilot who had a "hook skip" during F/A-18 CQ because they hit the divot spot on the carrier deck. Because of automatic (coupled) landings done by F/A-18 tailhooks contacting the same spot on the carrier, it made a small divot on the carrier deck, but was enough to bounce the hook and somehow missed 3 and 4 wires. They inspected the deck and repaired it pretty quick, and checked the tailhook was in spec, but it was kind of a surprise that an experienced pilot boltered while flying a tight ball, on a calm day. If a nugget did that, then they'd be like "yeah right..." but sure enough, it happened.

[spazsinbad]

A classic real story from the A4G/HMAS Melbourne era was the hook skip over 5 wire if the hook tip caught the slight rise in the deck from the aft edge of the aft lift (the no.5 wire straddled the aft part of this lift - no.4 {target wire if all five set} was a few feet before the lift). It happened regularly - with variations if the hook skipped earlier and bounced there, it would skip again. Everyone pooh-poohed this notion (except A4G pilots) whilst inspecting the non-smooth transition from deck to lift edge always brought the claim 'what is the problem?'. Answer: "It is not a smooth transition - there is a slight bump". Oh well, all razor blades in China now.

[KamenRiderBlade]

So is automatic landings / takeoff's preferred in this day and age due to enhanced computer accuracy / consistancy?

[spazsinbad]

In the coming JPALS/F-35C (and other suitable USN aircraft) automatic landings will certainly be more precise. These days with current setup Hornet pilots have to be encouraged to do fully automatic approaches (if otherwise they are not warranted due weather/emergency or other conditions) because these landings do not count apparently. Pilots also need to stay current with fully manual landings in all authorised conditions and semi-automatic (to manual takeover at half a mile or less) to remain current. For example if the pilot knows only automatic landings how does he land manually after a long spell with no manual landing practice? Also current completely automatic landings can be quite uncomfortable if the carrier is moving around a lot; but whatever; when needed the auto landings are a boon to tired long flight night return naval aviators. Search the forum for tall tales and true on these points. There was a fairly recent thread about all of this.

For example JPALS and JPALS equipped aircraft especially the F-35C will be able to target a particular wire. This may be important due weather conditions or state of the wires if unserviceable with only one available for example. I guess the USN needs a minimum of two wires out of four to be safe but it all depends I guess what the minimums might be if there is no alternative. If no wires and no BINGO field then a barrier engagement may be an option but this can be hazardous for some aircraft (depending). The F-35C will be tested at Lakehurst going into the CVN barrier at some point.

[count_to_10]

Eventually, an auto landing system should be able to compensate for the motion of the ship. Conceivably, you could end up with a sort of revers catapult system that precisely catches the aircraft coming in at a very high angle of attack on hardpoints, rather than landing gear.

[spazsinbad]

The JPALS does that to some extent especially when used with the BEDFORD ARRAY which will be in use on CVFs for F-35B SRVLs and potentially on CVNs for conventional landings (LSOs think it may be a good idea) early days though. Again search for 'Bedford' for some results here about this.

[batu731]

Great video and article. F-35 have so much more computational power than legacy fighters, its basically a flying super computer, therefore things like this come naturally.

[sferrin]

Eventually, an auto landing system should be able to compensate for the motion of the ship. Conceivably, you could end up with a sort of revers catapult system that precisely catches the aircraft coming in at a very high angle of attack on hardpoints, rather than landing gear.

Never happen.

[firstimpulse]

Eventually, an auto landing system should be able to compensate for the motion of the ship. Conceivably, you could end up with a sort of revers catapult system that precisely catches the aircraft coming in at a very high angle of attack on hardpoints, rather than landing gear.

Never happen.

Any reasoning behind that?...

[sferrin]

Eventually, an auto landing system should be able to compensate for the motion of the ship. Conceivably, you could end up with a sort of revers catapult system that precisely catches the aircraft coming in at a very high angle of attack on hardpoints, rather than landing gear.

Never happen.

Any reasoning behind that?...

You mean aside from the obvious issues?

[firstimpulse]

You mean aside from the obvious issues?

Well, they aren't too obivious to some of us...

[spazsinbad]

I'll assume that the 'high angle of attack' aircraft slotting into 'hardpoints' will be almost hovering (in the WOD) or will this aircraft be able to land with only aircraft carrier provided WOD (nil wind otherwise). If this approach landing is completely automatic then the pilot will have to be drugged somehow. OR will he be able to see through the aircraft to see/monitor the approach OR will an onboard instrument/HMDS III provide said view? I guess 'count_to_10' has the NASA F-16 high angle of attack research (or future similar?) aircraft in mind?

I think I would prefer the skycrane approach - hovering under it to be picked up by the sky hook to be deposited on deck. Some more explanation from 'count_to_10' about his idea would be nice.