F-35C Lands at Lakehurst For Testing

Production milestones, roll-outs, test flights, service introduction and other milestones.
  • Author
  • Message
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post19 Dec 2011, 09:33

Please 'alloycowboy' if you can delete the links in your post immediately above this one then free space will become available to show this post? Wiki or FlickR probably don't allow hotlinking that is why the moderators request any images be upload/attached as seen here. Thanks.

The two photos don't show so they are attached in ZOOM proportion with links:

http://upload.wikimedia.org/wikipedia/c ... hanics.jpg
&
http://www.flickr.com/photos/18842924@N ... otostream/
Attachments
USNleafSpringZoom.jpg
Last edited by spazsinbad on 19 Dec 2011, 20:38, edited 1 time in total.
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post19 Dec 2011, 10:11

This news item may be just a repeat of what is the the recent report (I have not had time to word check) however it will do to illustrate what apparently has been found so far.

New Articles and Information on the F-35 (Source: Center for Defense Information; issued Dec. 14, 2011)

http://www.defense-aerospace.com/articl ... ubles.html

"...F-35C Arresting Hook Problems Could Require Aircraft Redesign (excerpt)
(Excerpted from InsideDefense.com, Dec. 13, 2011)

The arresting hook system on the carrier variant of the F-35 Joint Strike Fighter is too short to reliably grab the cable on carrier decks upon landing and will require extensive modifications to fix -- and the aircraft may need a structural redesign if those don't work. (…/…)

The arresting hook system (AHS) for the F-35C, which failed on all eight attempts to connect with the cable in recent roll-in arrestment testing at Naval Air Warfare Center Aircraft Division Lakehurst, NJ. And, with rolling engagements looming in April leading into full carrier suitability demonstrations of the F-35C, the report states that the program doesn't know how significant of a redesign will be needed.

"There are significant issues with respect to how the CV variant's AHS interoperates with aircraft carrier-based MK-7 arresting gear," the report states. "Root cause analysis identified three key AHS design issues: (1) the aircraft geometry has a relatively short distance between the aircraft's main landing gear tires and tailhook point (when lowered), (2) tailhook point design was overemphasized for cable-shredding features versus ability to scoop low-positioned cables, and (3) tailhook hold-down damper performance is ineffective to support damping of small bounces relative to runway/deck surface profiles." (end of excerpt)" ENDS
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post19 Dec 2011, 10:20

Perhaps a 'telescopic' hook will allow it to lengthen when released from present situation? Perhaps that won't be needed if otherwise the hook point is redesigned to work properly. Not sure if a telescopic hook has been used before but it could lengthen in a fail safe way and shorten by a mechanism if hook is brought up again - on a bolter to bingo perhaps. Funny story about that when an A4G bingoed at night with pilot forgetting to raise hook so he surprisingly or not short field arrested (also did not check hook state before landing) back at NAS Nowra. I'm not privy to all the details because it was not I.

I guess a telescopic hook would make the entire hook structure unnecessarily bendy so it is not a good idea eh. Damper performance should be easy to fix. We wait and see - as always.

It is not only the hook catching performance onboard that is vital but also in the short/long field arrest situations. The aircraft carrier flight deck springs probably can be adjusted somewhat; but there is always a limit for the aircraft tyres etc. The rubber grommets that hold up the shore arrest gear have a limit also most likely. Only 'roll-in' tests have been done so far which is not a 'carrier arrest simulation' at all but it does point to issues. The hook has to work in all required situations. IF the hook doesn't work in one then it is no good at all.

Certainly the springs help a great deal with the hook hitting the deck before the main wheels hit so that the hook is catching a wire undisturbed by the wheels. Life ain't like that though as we have seen from the reports and photos. Probably the situation more serious ashore due to the fixed nature of the wire with the aircraft not flying into the wire (although I had to do that once) with usually the aircraft rolling along the ground immediately before the short (or long) field gear. Another thing to keep in mind is that the hook is not strong enough to be trailed along the runway too much because it might fail - that was a consideration in the A-4 for example so NATOPS warned to aim to 'fly into' the short field gear if possible and to not drop the hook too soon if planning to hit the long field gear. I cannot say today how long it takes a hook to drop but probably as long as a penny (or shoe as the Yanks say). :roll: :lol:

The excellent videos of the successful F-111 no wheels arrest at RAAF Amberely had me horrified at the time because the hook was dragged through the dirt and over the concrete lip of the runway before making a successful arrest. I guess the F-111 hook was good for that treatment. Alls well that ends well. No further complaints from me.

Pic below shows 'grommets' - I'll add links later to info on the graphic.
Attachments
GrommetsShortFieldGearEXTRA.gif
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post19 Dec 2011, 12:49

Two fore and aft photos of the same TA4G approaching the short field arrest gear for a demo arrest at NAS Nowra May 1980 - Photos by Wal Nelowkin:

http://jetphotos.net/viewphoto.php?id=6481741&nseq=211
http://jetphotos.net/viewphoto.php?id=6488872&nseq=202

In the first photo the orange light in the wing root near fuselage indicates the TA4G is at Optimum Angle of Attack. The only way to fly. Last photo shows and A4G in 1969 on way to threshold of RW 21. The TA4G is short field arresting on the same runway (in other words it will arrests using the BAK-12 gear shown). The info about ashore arrest gear limits is from the T/A-4G NATOPS of that era c. 1970s.

The 2nd last photo montage clearly shows at top the effect of RAAF Hornet hook dragging along the runway at NAS Nowra (after the A4Gs had departed for NZ).

The last photo by Don Simms (recently published a book about A-4K) shows moment of short field arrest on RW 21 NAS Nowra. Inset shows a fast slow flyby dirty before going around again for the arrest.
Attachments
TA4G880shortFieldArrestNASnowraforeAft.jpg
ShortLongFieldGearNASnowra1969.jpg
A-4natopsAshoreArrestInfo.gif
RAAFhornetRW26nasNowra.jpg
RNZAFa4KnasNowra1991donSimms.jpg
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

marksengineer

Active Member

Active Member

  • Posts: 192
  • Joined: 18 Jul 2011, 21:01
  • Location: Ohio

Unread post19 Dec 2011, 17:25

At 140 knots or 233.33 feet per minute (if my math is correct) the time it takes to travel 7 feet is 0.03 seconds. From posts on the thread we know that the cable can spring back up far enough for the hook to engage it in twice that time as the Skyhawk has 14 ft between wheels and deployed hook. The question is where will the cable be after .03 seconds? Would assume that the spring rate is dependent on cable tension. In any event the correct postioning of a high speed camera should provide the data. The problem may be that the spring rate is non-linear taking more time to move the first inch or so than the rest of the travel. Any ideas?
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post19 Dec 2011, 19:51

marksengineer, AFAIK from above post about the 'roll in' runway arrest tests ashore that failed - these would have been done on the 'grommet held' arrestor gear as shown above. I don't know if Lakehurst has 'spring held' carrier arrestor gear installed. They may well have so I'm only guessing. Onboard there are other variables such as the 6 degrees of movement of the ship - the most important I guess would be the up/down motion of the back end and heave. In that small time frame mentioned though that would be not so much. Onboard USN aircraft carriers I don't really know anything about the CDP tension or springs etc. other than what can be googled. Their system of info in Aircraft Recovery Bulletins ARBs has a lot of detail but I"m not able to access that system. I'll look around - meanwhile here is an USN arrestor gear onboard cutaway diagram & Mk.7 Mod.3 details from:
[Mystery solved about 'Wire Supports' as they are now called in USN - see diagram/text from same source below]

http://www.globalsecurity.org/military/ ... /14310.pdf (mentioned with edited version downloadable elsewhere)
Attachments
ArrestEngineCDPusnDiagram.gif
Mk7mod3USNarrestorGearDetails.gif
USNarrestorWireSupports+.gif
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

alloycowboy

Forum Veteran

Forum Veteran

  • Posts: 821
  • Joined: 26 Oct 2010, 08:28
  • Location: Canada

Unread post20 Dec 2011, 00:45

@ spazsinbad...... Thanks for the help, I was working on a post when the power went out, I just assumed that post was lost.
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 00:51

alloycowboy, the post without the pics is on page 5. You can leave the question and just delete the links that don't work to free up space. The edit function has many more minutes these days.
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

alloycowboy

Forum Veteran

Forum Veteran

  • Posts: 821
  • Joined: 26 Oct 2010, 08:28
  • Location: Canada

Unread post20 Dec 2011, 01:05

Thanks Spazsinbad..... Done!
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 02:01

On the previous page 'alloycowboy' asked: "After the F-35 main landing gear rolls over the cross deck pendant (cable) it is the spring rate of the these leaf spring "risers" that may ultimately determine whether the F-35 traps or not."

There are many variables. Probably ideal (as we see in many photos) is that the hook catches a wire after the main gear passes overhead before touchdown. Often you will see photos (the super hornet is a classic) with the aircraft still airborne by inches but already decelerating due to beginning of arrest. All measured in micro inches and high camera shutter speeds though. I'm not describing an 'inflight arrest' which is altogether different. Just an ideal normal arrest. See pic Zoom...

Then the variations will start if for example there is a hook skip over a wire to catch the next one which may or may not have been 'trampled' already. How the aircraft lands can affect hook behaviour with different aircraft having different 'hook' characteristics. For example in the A-4 'wing waggling' in close (last second line up change) would set the hook swinging, decreasing chances of a good arrest and possible bolter. One thing to consider with a long hook but perhaps today different hook attachments help minimise any swing. Then at least on HMAS Melbourne the A4G hook could bounce enough to miss one or two wires for a bolter. However often there might be once bounce over a short wire to catch a long wire for example. The pilot only knows about this via the LSO afterward. The USN have had the benefit of PLAT tapes since around the early 1960s to see playbacks of approaches from different angles. However the quality is poor so being able to see these minute events is not likely in a freeze frame. Probably new PLAT today [ILARTS] is very much better.

IF an aircraft touches down main wheels before the first wire No.1 then that is referred to as a 'Taxi 1' (taxi up to the first wire) and would be grounds for much consternation by all and sundry. Too many of those would see a pilot being beached. Luckily the big USN carriers have a lot of flight deck before the one wire (all relative though). On smaller carriers a 'taxi 1' is extremely dangerous. So that is an example albeit extreme of how the main wheels can touch down before a wire is caught. A hook may bounce over a wire, then main wheel touchdown then hook catches next wire that has just been run over. Or the next one. And so on. I don't believe it is much of an issue with USN aircraft today but apparently - by all acounts - the F-35C has a problem.

Anyway back to the question. I don't believe the 'risers' depress much at all. As long as tension + riser keep the wire at required height. I have not examined high speed film to know the behaviour of this system in minute detail. The wire is temporarily deformed by main/nose wheels as we saw in the InstaPinch photo series. However we consider main wheels because they touch down first. If we are considering nosewheel then likely the aircraft is beyond the wires boltering. But then again USN carriers are quite lengthy in the flight deck. :D

This sort of 'riser' arrangement could only be considered ashore if the wire could be guaranteed to rest on the runway when not in use. In fact some civilian aircraft will not land before a wire on grommets but land long to avoid running over it. The BAK-14 has an arrangement that will hide the wire below the runway when not in use AFAIK.

[Addition] Keep in mind that the ship may have equipment changed (such as AAG Advanced Arresting Gear) but the F-35C must be able to fit in with equpment restrictions planned to be in use. The equipment is set ideally for today's USN aircraft.

Pic Zoomed from previous page and here: http://www.villanova.edu/artsci/assets/ ... imized.ppt
Attachments
SuperHornetTRAPzoom.jpg
Last edited by spazsinbad on 20 Dec 2011, 02:51, edited 1 time in total.
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 02:34

T-45C Goshawk Trap - nosewheel still to hit deck with main wheels making smoke at touch down point after the arrest wire being caught by hook:

http://www.navy.mil/management/photodb/ ... 5G-001.jpg

"040417-N-4565G-001. Atlantic Ocean (Apr. 17, 2004) - Lt.j.g. Julin Rosemand, assigned to Fixed Wing Training Squadron One (VT-1), completes a successful landing in a T-45C Goshawk aboard USS John F. Kennedy (CV-67). VT-1 is going through Carrier Qualifications (CQ) as Kennedy is completing her final training prior to a scheduled upcoming deployment. U.S. Navy photo by Photographer's Mate Airman Tommy Gilligan."
__________

And a hook swinging turkey waddling arrest photo from beyond....
______________

And an arrested Hornet...
___________

Good illustration hook before wire before main wheels in the wet....

Story here: ‘Whisper: Still Life’ By Whisper, on March 6th, 2011
http://www.neptunuslex.com/2011/03/06/w ... /#comments
http://www.neptunuslex.com/wp-content/u ... 0087-1.jpg
________________

Lastly Hornet No.3 wire arrest (if no hook skip)....
Attachments
040417-N-4565G-001.jpg
TurkeyWaddleTrap.jpg
ArrestThisHornet.jpg
IMG_0087-1.jpg
Hornet3wireArrest.jpg
Last edited by spazsinbad on 20 Dec 2011, 02:57, edited 2 times in total.
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 02:50

Always instructive to know how tuff youse boing is:

F-18 Catch and Bouncy Ride

http://www.military.com/video/aircraft/ ... 575058001/

"Posted Feb 07, 2007 by William Benner An F/A-18 E in a mid air engagement of the arresting gear onboard caught by ILARTS system."
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 03:19

Video Utube shows A4G hook swinging due aggressive late lineup corrections HMAS Melbourne in late 1970s:

http://youtu.be/yXnwHyIHQvM
Attachments
SwingingHookA4G.jpg
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
Offline

sprstdlyscottsmn

Elite 4K

Elite 4K

  • Posts: 4536
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az, USA

Unread post20 Dec 2011, 05:09

Ouch, that last F/A-18 vid looked like an attempted bolter turned into a 4-wire (or is it 1-wire, don't know which way they count) and I would be shocked if that oleo didn't burst.
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23493
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post20 Dec 2011, 05:58

There are some comments about the approach here (only from ILARTS/PLAT which will not be the same view the LSO will have):

Rhino Cut to an IFE By lex, on May 16th, 2011

http://www.neptunuslex.com/2011/05/16/r ... to-an-ife/

"A late wave-off causes a Super Hornet to engage the one wire while coming up to fully power in this Military.com video....

PLAT LSO says, “C: (LULX-IM) _NEPSAR_ _TT1_”

Bet that was a wild ride."

NepLex LSO comments are then translated by him: "Cut Pass – A little lined-up left start-to-in-the-middle, not enough power settle at the ramp (underlined), taxi, taxi one wire (underlined)"

Cut pass means 'epic fail'. You see the notorious 'taxi 1' term also. I don't have sound so cannot hear and cannot be certain if the aircraft is waved off to then catch an IFE InFlight Engagement.

NOSE (LSO also as is Lex) comment: "Nose May 17, 2011 at 3:44 am
Fred, it is never too late to waveoff an unsalvageable pass. They were afraid this guy was gonna hit the rounddown [ramp]. However, if your implication is they hit the pickle [activate waveoff lights (or call 'waveoff')] a little too late, I may agree with you. Not having audio on the PLAT makes it harder to tell...."

Then Lex recomments: lex | May 17, 2011 at 5:44 am
Nose is exactly right (of course), you’d hate as an LSO to jump into the net and not have the wave-off lights witnessed on the PLAT tape. It’s just bad form.

Like a lot of bad landings, the guy was looking pretty good right up until the moment when he wasn’t (people who aren’t looking good from the start to in-the-middle get to try it again) [WAVED OFF!]. For whatever reason he ran out of smack [power] and the LSOs did what they could to keep him off the ramp.

I didn’t see him pull the nose up on a wave-off, which is also bad technique as it can cause an inflight engagement by “extending the hook.” No, it appears to me that he was fully landed and somehow managed to get the jet airborne again after having grabbed the ace [no.1 wire I assume?]. - Ugly."
_________

No carrier pilot wants to bolter deliberately. It is not a bad thing if happens due to 'hook skip' but 'bad' if pilot induced (like any carrier approach there are degrees of good/bad). A bolter means hook has missed the wires for a reason. IF hook not down then that is a touch and go and counts as a deck landing. Wires counted from ramp (back end) with No.1 first and No.3 is target wire.
___________

ADDITION: BTW the carrier approach glideslope is set for each aircraft type so that the hook will hit the deck midway between No.2 & No.3 wire (to catch 3). Graphic from here: http://www.dtic.mil/cgi-bin/GetTRDoc?Lo ... =ADA469901
Attachments
TargetWireNo3graphic.gif
Last edited by spazsinbad on 20 Dec 2011, 09:05, edited 2 times in total.
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
PreviousNext

Return to F-35 milestones

Who is online

Users browsing this forum: No registered users and 3 guests