Forum: F-35 milestones

Another 'golden oldie' test document for John Will. Very Happy

NO HOOK C-130 carrier landings elsewhere on this forum (on this thread?).

DEVELOPMENT OF MODEL 3500 ARRESTING GEAR AND CONTINUED DEVELOPMENT OF SPRING HOOK FOR COMMERCIAL AIRCRAFT M-788 PART 1 January 1963

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0408963 (PDF 6.5Mb)

Testing arrestor hooks for C-131B and Boeing 720 aircraft results.

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spazsinbad,

Thanks very much for posting that bit of ancient history. I wasted a good two hours reading it. All those hand-written test data sheets and plots and the horrible way photos were copied by the Xerox machines of the day really brought back not-so-fond memories of test programs I worked starting that same year. I hope today's engineers appreciate how far equipment and methods have advanced compared to fifty years ago. I would not want to go back to the old ways, but I wouldn't take a million bucks for the experience.

Apparently, the idea of emergency arrestment systems never caught on for commercial airports. Although the need is rare, there have been several cases where such a system could have saved many lives.

Thanks again Cheers

Lockheed Martin Answers Critics Of F-35 Program Farnborough Air Show » July 9, 2012
by Bill Carey and Chris Pocock

http://www.ainonline.com/aviation-news/ ... 35-program

"...• Ground testing discovered F-35C tailhook design issues that have major consequences, according to DOD officials. Aircraft structural modifications may be required.

O’Bryan acknowledged that problems with the F-35C tail hook design are delaying the first test flights to an aircraft carrier, but said the plan is to “go to the boat” with a redesigned tail hook in early 2014, “well in time to make” the U.S. Navy’s planned initial operational capability for the F-35C carrier variant.

The distance between the main landing gear and the tail hook on the F-35C is the shortest of any naval carrier aircraft, and the hook must be hidden to maintain the aircraft’s stealth profile, O’Bryan said, explaining the design challenge.

The redesigned hook shank has a lower center of gravity, or, in effect, a sharper point, to catch the arresting wire on the carrier deck, he said. In addition, a “hold-down damper” is being modified to keep the hook from bouncing or skipping on the deck. “The good part is this whole assembly is a remove-and-replace assembly so any modification that we make to it is an easy fix,” he said. The redesigned tail hook is being tested by doing “rolling arrestments” with an F-35C at the Navy’s Patuxent River, Maryland and Lakehurst, New Jersey carrier suitability test sites...."

First Bomb Drop Ahead For The F-35 09 July 2012 by Amy Butler

http://www.aviationnow.com/Article.aspx ... ml&p=1

"...Work also continues on a redesigned tailhook and dampener for the F-35C. The original design failed to grasp the arresting wire in slow, ground-based trials last year. Carvalho says Lockheed Martin began testing the tailhook—which has a sharper point designed to scoop under the wire—in May and it “caught the wire every time” in ground tests. Work is also underway on the dampener, and Venlet hopes to see it tested by early fall. The first arrested landing on a runway is expected in 2013. The aircraft is due to start carrier trials at sea in 2014...."

'johnwill' perhaps this 'soft ground' system is an answer? "JW... "Apparently, the idea of emergency arrestment systems never caught on for commercial airports. Although the need is rare, there have been several cases where such a system could have saved many lives."]

ESCO's Engineered Materials Arresting System, EMASMAX TM VIDEO

http://www.youtube.com/watch?v=45IcXrqRjEY

“Uploaded by ravenarrestor on Mar 31, 2009
Although ESCO has been developing and providing arresting systems for military applications for over 50 years, it wasn't until the early 1990's that the FAA approached ESCO to help develop a soft-ground arresting system for commercial airports and transport category aircraft. Working under a Cooperative Research and Development Agreement (CRDA) with the FAA, PANYNJ and others, ESCO developed a new type of predictable and reliable soft-ground arresting system. ESCO's Engineered Materials Arresting System, EMASMAX TM, has the distinction of being the first, and currently only, engineered aircraft arresting system certified for airport runway safety areas and satisfying Part 139 requirements. ESCO sets the standard for providing quality and reliable products and services. We offer a full range of services including design, production, installation and technical support.”

RIGHT CLICK ON THE PLAYING MOVIE TO SELECT THAT 'FULLSCREEN' GOODNESS! Rolling Eyes

Salute!

Hey, Spaz!

Why don't we get a separate thread. The name of this one seems more relevant to on-going activities at Pax River or Lakehurst, ya think?

Gums sends...

Posted elsewhere also but thought to get this thread back on track.

The CNO Said What? by Bill Sweetman | Jul 20, 2012

http://www.aviationweek.com/Blogs.aspx? ... 6bf2e0943a

"And the F-35C's key milestones continue to slip. In January, even after tailhook problems had been disclosed in the Quick Look Review report, the first carrier landings were planned for summer 2013. The date is now "early 2014" following roll-in tests at up to 100 knots. "Initial tests were promising," says Lockheed Martin chief test pilot Al Norman, "but we are working on the pressure that we use to hold the hook down."

A scenario for testing F-35C is perhaps mirrored by recent Super Hornet Testing at Pax River as described below. The relevant PDF page (graphic/text is replicated below) says it all....

Unnatural Acts of Landing Patuxent River Naval Air Museum Association
The Kneeboard Mag'n Spring 2012

http://api.ning.com/files/8OBnZkm85rrIM ... ng2012.pdf (1Mb)

"For most people, the idea of flight testing means seeing how fast an airplane can go or how quickly it can maneuver. While answering these questions may be part of a flight test program, there is more to flight testing than speed and agility. Navy carrier aircraft must also withstand the stressful loads of repeated arrested landings (traps) that can exceed 6 Gs on the aircraft.

The landing gear must:
* Survive thousands of landing shocks
* Reduce the loads reaching the aircraft structures and crew
* Allow the pilot to stay in control of the aircraft’s behavior

Ground Loads Testing shows that an aircraft structure can withstand carrier operations at maximum takeoff and landing weights. Normal landings at these conditions are no problem. But testing must also show that an aircraft can absorb these loads when:

* Its sink rate (how fast it descends) is high (as much as 26 feet per second!)
* Its wings are not level when it lands
* Its tailhook catches an arresting cable to the side of the center line
* The carrier deck pitches and heaves...

...During Super Hornet development, Ground Loads Testing required 125 test flights, 370 catapult launches, 471 traps, and three years to complete. Incidents included blown tires and various airplane parts (other than the wheels and tailhook) hitting the deck."
&
"What Is a “High Trap”? Normally when an aircraft “traps” (lands on a carrier), its wheels contact the deck (or the runway during practice landings) just before the tailhook snags the arresting cable. But sometimes the tailhook will engage the arresting cable before the wheels touch down. This is known as an “inflight engagement” or “high trap.” Both the aircraft and the pilot are slammed down hard as the aircraft is suddenly snatched from the air. These are not fun landings."

Thanks, spazsinbad, for more interesting posts. Seeing those pylons and stores under the SH wing reminds me of the very large loads imposed on those items on the carrier deck. During the late 70's some weapon rack contractor (I forget who) was trying to develop a new multi-store rack for the Navy and Air Force. They needed some realistic structural loads for design, so asked General Dynamics to help out. I was leading the store loads analysis team at the time, so got the job. Finally comes the interesting part - of all the six critical design conditions (including maneuvers, separation, takeoff, landing) five of the conditions were on the carrier deck.

The new rack was a total failure - too heavy, too draggy - and never even made it to flight test.

Back on page 3 of this thread around 13 Dec 2011 ( http://www.f-16.net/index.php?name=PNph ... 26462ae091 ) the 'tailhook for F-35C roll-in arrest failures' became known. Subsequently a redesign of the hook mouth (more like A-4 hook) meant that roll-in engagemnents were successful with more tests to come. Anyway one criticism implied was the 'yoke' design and we will get to that.

Just for the record as noted on page 7 of this thread: F-35 Lightning II Program Status and Fast Facts 01 Nov 2011

http://f-35.ca/wp-content/uploads/2011/ ... 1-2011.pdf

"* As of Oct. 31 [2011], F-35C jets had executed 59 successful catapult launches and three arrestments." The cat/arrest test facilities are more or less at the same place at Lakehurst.

Then 'alloycowboy' introduced A-4 hook examples so in the spirit of that aircraft and the comment about A-4 "simple design": INFO:
http://a4skyhawk.org/content/137812-dou ... t-photo-13
"Variant: XA4D-1 Custodian: Douglas BuNo: 137812 Location: El Segundo
Date: circa 1952 Contact: G. Verver Photo Credit: Douglas Aircraft photo
Description:
right side view of the Douglas A4D Skyhawk mock-up"

Actual photo at the A-4 Association: http://a4skyhawk.org/sites/a4skyhawk.or ... 7812m1.jpg

Anyway now on page 11 there is this comment by ELP:

"Some other interesting A-4 trivia. The designer stressed simplicity above all.
And the original design came in way under-weight to the requirement. Add to that, from the early model to the later models, the design had a around a 25 percent growth in empty weight.
Do you see those kinds of margins with the F-35 design?
I am also curious about a yoke hook design on the F-35C. What does that mean?"

As one can probably guess the mock up A-4 YOKE HOOK design was replaced early on, along with a bunch of other stuff most likely. Curious huh. Very Happy

The early A-4s had nothing much at all in them and of course over time a lot of stuff was crammed in (including the hump on top) which was deleted when KAHU upgrade with modern electronics meant even more TRON stuff could be crammed inside.

However subsequently the 'lightweight' early A-4s had to have structural beef ups in some parts due to inadequate 'weightage'.

Ya think more info could be provided (considering what a song and dance was made about this issue earlier - at beginning of this year) but no....

Marines to start F-35 training at Florida air base By Andrea Shalal-Esa, Aug 22, 2012

http://www.reuters.com/article/2012/08/ ... mesticNews

"...The Navy's F-35C or carrier variant of the new fighter jet also recently completed testing of a redesigned arresting hook at a facility in Lakehurst, New Jersey.

One source familiar with the tests said they had proven largely successful, although there was still more work needed to ensure the jet could safely land on an aircraft carrier."

That's some good news, even if AW attempted to bury it at the end of loosely related story.

1st503rdsgt wrote:

That's some good news, even if AW attempted to bury it at the end of loosely related story.

Some people's wins are others losses. Crying or Very sad

BS still has hope of the -35 failing anywhere, anyhow and at anytime, surely there is a god, Editors at AW would not "feel the warmth" if an article highlighting a -35 improvement or successful solutions were to be published about the (SDD) Test aircraft or program. No need to offer hope for successful solutions, only whining about development problems. Laughing

neptune wrote:

1st503rdsgt wrote:

That's some good news, even if AW attempted to bury it at the end of loosely related story.

Some people's wins are others losses. Crying or Very sad

BS still has hope of the -35 failing anywhere, anyhow and at anytime, surely there is a god, Editors at AW would not "feel the warmth" if an article highlighting a -35 improvement or successful solutions were to be published about the (SDD) Test aircraft or program. No need to offer hope for successful solutions, only whining about development problems. Laughing

While I am no fan of Av Week nor of BS, it wasn't an Av Week article; it was a Reuters article that Av Week put a link to in the "Recent Articles' section of Defense.

Did I miss something or are we having Pavlovian reactions to something posted about F-35 in Av Week?

Before the complaints start rolling in for arrestment - bear with me here. Do we not see parallels with some other aircraft? Wot you say!? F-35C? My goodness me... Ya just couldna make this shite up! Very Happy

Who maketh the X-47B? Hmmmm....

Fleet Readiness Center “hooks up” unmanned aircraft 05 Sept 2012

http://www.navair.navy.mil/index.cfm?fu ... mp;id=5114

"NAVAL AIR STATION PATUXENT RIVER, Md. – The Fleet Readiness Center South West (FRCSW) in California surpassed the call of its traditional line of work to rapidly manufacture parts for a new, unmanned demonstrator aircraft being tested here.

In late spring, a team from Patuxent River, Md. called on FRCSW at Naval Air Station North Island to redesign the hook point for the first unmanned aircraft designed to operate in and around an aircraft carrier — the X-47B Unmanned Combat Air System (UCAS).

To land on the flight deck of a carrier, aircraft need a tailhook to catch one of four arresting wires. When unsuccessful roll-in arrestment tests of the X-47B revealed the need for a modified hook point, the team needed to come up with a plan to make the modifications in order to perform arrested landings and catapult launches this fall.

“We reached out to the team at North Island because of their proven history of providing critically needed aircraft components with very short response times,” said Capt. Jaime Engdahl, Navy UCAS program manager at Pax River. “They have repaired, modified and delivered thousands of high quality aircraft components to the fleet. We knew they could get the job done.”

Seventy years earlier, North Island personnel were presented with a similar challenge. Prior to the Battle of Midway, a lack of tail hooks, and the inability of the American industrial base to produce them, spurred FRCSW, then known as Overhaul and Repair, to develop a way to forge and manufacture 150 hook throats in just 30 days.

The team at FRCSW did not hesitate when asked to redesign this instrumental X-47B component. Within a few weeks of receiving the initial request from the UCAS team, the FRC signed a formal work order July 10, anticipating the manufacturing and shipping process would take up to one month.

The UCAS and FRC teams worked together to overcome a series of complications to ensure the hook points were completed as quickly as possible. For example, machining the first steel part took longer than expected. As a result, the FRC made an investment in a more efficient machine to decrease cycle times.

In less than two months, despite the design challenges, the UCAS team received the completed parts from FRCSW in early August, avoiding costly delays and allowing the team to proceed with aircraft testing. Since then, the X-47B successfully engaged the arresting gear with the redesigned hook point during three separate roll-in arrestment tests.

“The hook point is a fracture critical safety item so you’ve got to do the job right. You have to create them correctly,” said Mike Grice, FRCSW Systems Engineering department head.

Engdahl visited North Island last month and personally thanked the dozens of employees who worked extended hours for nearly two months to support this effort. The FRCSW team made a huge contribution to the UCAS program that will greatly impact naval aviation, he added."

BIG PIC Caption: http://www.navair.navy.mil/img/uploads/ ... _Still.JPG
"The X-47B Unmanned Combat Air System (UCAS) demonstrator aircraft completes a successful roll-in arrestment with a modified arresting hook point designed and manufactured by Fleet Readiness Center Southwest (FRD-SW) Aug.14 at Patuxent River, Md. FRCSW delivered the hook point just 46 days after receiving a request from the Navy UCAS program office."
__________________________

SOME MORE TECHO INFO ON THE PROCESS HERE:

FRCSW Innovation Solves Navy UAV Problem Sep 5, 2012

http://www.navair.navy.mil/index.cfm?fu ... mp;id=5116

Forum: F-35 milestones

F-35C Lands at Lakehurst For Testing