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F-35 Cancelled, then what ?

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F-35 Cancelled, then what ?

Old 28th Aug 2016, 16:02
  #9681 (permalink)  
 
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Glad,

Perhaps I can help - although I'm definitely not an expert.

The steering is controlled exactly as MSOCS says. The only thing I'd add is that the F-35C is nimble about the deck because it's designed that way. The twin wheel nose gear allows 'spot turns' as well as very precise positioning of the aircraft. (It is also a key part of the USN specification for attachment to the catapult shuttle, and nose gear behaviour during launch). Precise control is important on any carrier deck, even more so with cat and trap, where the aircraft has to be controlled to within an inch or so to engage with the catapult gear. In addition, some of the deck spotting patterns require very exact positioning.

Some readers may not know that marshalling signals on flight decks are mandatory, not advisory as on land bases. The 'yellow shirts' you see in these clips are highly trained and experienced, and they need to be. They are making a difficult job look easy. Before powered steering nose gear, moving jet aircraft around on flight decks was quite a challenge, especially where space was tight on some of the smaller carriers. The UK came up with some very ingenious 'roller' systems that positioned the aircraft on the catapult.

The F-35B gets away with a (much lighter) single wheel nose gear because the F-35's basic braking systems are very good, and the main gears are widely spaced. As MSOCS so rightly points out, the aircraft can do very compact spot turns if required. The undercarriage layouts of the Sea Harrier (and the GR7s) were, frankly, a bit of a mare on small flight decks, with any spot turns risking loss of an outrigger tyre. F-35 is a real step forward in this respect.

Hope this helps, best regards as ever to the yellow shirts doing the business out on deck,

Engines
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Old 28th Aug 2016, 18:38
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Indeed Engines, a single-wheel nosewheel needs just a wee bit of forward motion before gradually throwing full input in, unlike the C's layout.

gr, not interested in sounding like an expert, just being good at my job.
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Old 29th Aug 2016, 06:19
  #9683 (permalink)  
 
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The hands-off launch is used because the steam catapults produce peak accelerations high enough to cause a temporary loss of pilot consciousness. The new EM catapult systems may reduce the peak launch accelerations experienced by carrier pilots so it is less of a problem.

Drivers of NHRA Top Fuel dragsters and Funny Cars experience higher peak acceleration rates at launch than carrier pilots. Occasionally up to 8g's at launch, during a run lasting less than 4 seconds at top speeds over 300mph. The drivers wear neck braces and mouth guards to keep from damaging their teeth or biting their tongues.
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Old 29th Aug 2016, 06:59
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"Temporary loss of consciousness"? not likely nor safe - never happened. However... the catapult stroke on HMAS Melbourne was 100 feet (lengthened c.1971) at 6 G and it all happened in less than two seconds (quoted and I was not counting) to around 100 knots wheel speed for an A4G Skyhawk. The effect I liken to a punch in the chest that was painful but no loss of consciousness. The G loading at launch is fore and aft; the Skyhawk was rated to 9 G maximum in that direction specifically for max. load catapults in difficult environments (hot day - nil wind etc.).

And to comment on the link info below: there is a thread about F-35C catapult already mentioned recently whilst both hands of the F-35C pilot are on the towel racks during catapulting. Specifically in the case of the Skyhawk a drop down handle was provided that was clutched together with the throttle at full power for catapulting so that the throttle could not be reduced during the launch. The right hand was cupped in the stomach to catch the stick moving back during launch. Scroll down the page at 'Canute' URL below for a more detailed description.



Last edited by SpazSinbad; 29th Aug 2016 at 07:14. Reason: text add fore & aft G
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Old 29th Aug 2016, 07:01
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Originally Posted by riff_raff View Post
The hands-off launch is used because the steam catapults produce peak accelerations high enough to cause a temporary loss of pilot consciousness. The new EM catapult systems may reduce the peak launch accelerations experienced by carrier pilots so it is less of a problem.
Nope.

Hands off the controls during carrier catapault launches [Archive] - PPRuNe Forums
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Old 29th Aug 2016, 19:49
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Engines: ...The twin wheel nose gear allows 'spot turns' as well as very precise positioning of the aircraft. (It is also a key part of the USN specification for attachment to the catapult shuttle, and nose gear behaviour during launch)...

....The F-35B gets away with a (much lighter) single wheel nose gear because the F-35's basic braking systems are very good, and the main gears are widely spaced....



Would like to get someeducation on single vs twin nose wheel dynamics for catapult capable aircraft.





As I understand the twin nosewheel has become essentially standard with the move from bridle launchedaircraft to nose gear launched aircraft. The nose gear seems much more heavily loaded and the twin nose wheels straddlethe catapult track where the shuttle goes. Some bridle launched aircraft such as the F-4 had twin nose wheels, manydid not.



So how did/do aircraft with asingle nose wheel such as the A-4, F-8 and Super Entendard get away with “mindingthe gap’? Was the tire (tyre for my UKfriends) not cut on the track? Was it amatter of the bridle launch cable imparting much less load on the nose tire andmore of the strain on the mains? I notethat ALL nose gear launched aircraft have twin front tires and have a noticeable nose down compression orbobble immediately as the catapult strokes. One poster seemed that this bobble on the C seemed excessive, but itlooked similar to any F-14 or F/A-18 stroke.



So were some bridle launched aircraftable to get away with a single nose tire?



Happy for any insight- thanks, Dave

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Old 29th Aug 2016, 23:21
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Complex & Robust Flight International F-35 Special 2014
"Mark Ayton explains the highly complex landing gear systems used on the F-35...

......Patented by Carpenter Steel, Aermet 100 has very high strength and slow crack propagation properties, so if a crack develops in the material, the crack will spread slowly with further load applications. By contrast 300M or 4340M grade steel has the same strength quality, but poor crack propagation. This gives more opportunities to discover cracks in the structure before a catastrophic failure occurs.

Each type of F-35 landing gear has a Goodrich-proprietary system integrated within the aircraft’s maintenance system to help the maintainer assess the level of the gas and oil in each shock strut during servicing....

...Cats and Traps
Landing gears for the F-35C CV variant have to be able to withstand extreme high energy landings typical of naval aircraft operating from an aircraft carrier as well as the nose tow launch. Both the F-35C nose and main gears are made primarily of Aermet 100 steel.

The nose gear of the CV variant is a dual stage gas over oil cantilever strut with a staged air curve that provides a source of high energy, which helps the aircraft to achieve adequate angle of attack when released from the catapult during take-off from the aircraft carrier. The CV nose gear carries a complex mechanism which positions the launch bar in readiness for various stages of operation during the launch of the aircraft off the carrier. The mechanism is driven by a power unit comprising a number of powerful springs and a small internal actuator.

There are two reasons for having a staged shock strut for the nose gear on the F-35C CV variant. One is to provide a stable platform for loading and unloading weapons and for engaging the catapult equipment. The second is to store energy gained from the compression of the strut under the high pressure effect of the catapult. When the catapult lets go of the launch bar, the energy is released, providing a rotation that helps achieve the angle of attack necessary to get off the deck.

Similarly when the aircraft hits the deck on landing the strut is compressed and energy is stored to help rotate the aeroplane and get it back off the deck if the arrestor cables are missed and a ‘go-around’ or ‘bolter’ is required. Bolter is the term used when the aircraft’s tail hook misses the arrestor cables on the carrier deck forcing the pilot to go around for another landing.

The CV nose gear also has a locking drag brace and a launch bar that acts to transmit the high launch load from the catapult equipment to the airframe. A separate retract actuator provides the force to retract the gear into the wheel well. One end of the retract actuator is attached to the landing gear structure and the upper end to the airframe structure. Fitted to the aft of the strut is a power unit housing an actuator that hydraulically lowers the launch bar to the deck to engage the catapult. When the launch bar hits the deck a second set of springs inside the power unit provide lighter power so that the launch bar can move up and down to engage the shuttle, without jamming or binding, or badly wearing the deck or the launch bar. Large powerful springs are able to pull the launch bar back up to an intermediate position when the hydraulic power is released.

The power unit also has a linkage that operates off the motion of the drag brace during retraction to position the launch bar in a stowed position (virtually parallel to the strut) when the gear is retracted. During the retraction process the launch bar moves upwards but also rotates around the strut to reduce the actual footprint within the stowage bay. The torque arms that typically maintain alignment between the strut piston and the steering unit are on the aft of the strut as well, and have a fitting at the apex that engages the repeatable release holdback bar (RRHB) of the ship. This bar holds the aircraft back during engine runs and while the load builds during the start of a catapult sequence. Once the load reaches an adequate level, the RRHB releases the torque arm fitting, allowing the aircraft to be catapulted to flight. In comparison to the F-35A CTOL and the F-35B STOVL, the nose gear of the F-35C CV has a dual wheel/tyre arrangement to straddle the catapult equipment and to adequately react to the loads. Nose wheels are the same as those used on the other variants but the tyre was developed specifically for the F-35C.

Like the CTOL and STOVL variants, the CV main gear is a dual stage gas over oil cantilever strut with staged air curves that provide a stable platform for loading and unloading weapons and hold stored energy to assist in getting airborne in the case of a ‘bolter’ during carrier operations.

The main gears have a retract actuator between the strut and the airframe, providing the force to retract the gear into the wheel well. Each also has a drag brace with locking linkage and locking actuator with backup springs to react fore and aft ground loads. The F-35C’s drag braces attach to a collar on the strut and a pivot pin in the aircraft that roll around the strut centreline during retraction to minimize the amount of space in the bay when retracted.

Featuring a long main strut the F-35C’s main gear has a shrink mechanism to shorten the strut prior to retraction so it will fit within the available space. The Goodrich-proprietary shrink mechanism utilizes a novel transfer cylinder to convert high pressure and low flow aircraft hydraulics into a low pressure and high flow shock shrink hydraulics. Unlike the nose gear, the CV main gear system utilizes the same main wheel and brake as the F-35A CTOL. All tyres used on the F-35C CV variant are significantly more robust than the CTOL and STOVL variants, because of the high energy landings on top of arrestor cables."
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Old 29th Aug 2016, 23:40
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Steam Catapult track of HMAS Melbourne is not a problem for single nosewheel tyre of the A4G Skyhawk. All A4G tyres were about double the air pressure (about 300 psi?) - compared to land - for carrier ops, arresting and catapulting. This could be a problem when landing ashore on short wet NAS Nowra runways, after being catapulted from the ship (and don't forget to arm the spoilers - not used onboard).



Last edited by SpazSinbad; 30th Aug 2016 at 01:06.
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Old 30th Aug 2016, 07:04
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Air Force Prepares to Hash Out Future Fighter Requirement | DefenseNews

WASHINGTON — After undergoing a yearlong effort that explored the tactics and technologies needed to control the skies in the future, the Air Force is taking its first steps toward making its next fighter jet a reality. The service has already begun preliminary work ahead of a 2017 analysis of alternatives that will shape the requirements and acquisition strategy for the F-35 follow on, which the Air Force been termed Next Generation Air Dominance (NGAD) or Penetrating Counter Air (PCA).

But Brig. Gen. Alexus Grynkewich, who led the Air Superiority 2030 enterprise capability collaboration team (ECCT), emphasized that there are two major differences between the NGAD effort and its that of legacy fighter jets. The first is the relatively rapid method of acquiring it. “We need to have something by the late 2020s,” he said in an interview with Defense News. “I think a realistic timeline is somewhere around 2028 with key investments in some key technology areas, you’d be able to have some initial operational capability of a penetrating counter air capability.” ..........

Requirements are not set in stone and could change during the AOA process, but Grynkewich believes that range and payload will be two of the most important attributes of the aircraft. NGAD, like other fighter jets, will need to be able to penetrate enemy air defenses and enter contested spaces, but it will also need to be able to operate at greater distances than current platforms, he said........

The Air Force is off to a good start, but still has much work to do in terms of establishing what performance variables will take priority, said Mark Gunzinger, senior fellow at the Center for Strategic and Budgetary Assessments. Like Grynkewich, Gunzinger mentioned payload and range as two key characteristics of the aircraft.

“When you consider the kinds of geography that our future fighter aircraft may have to operate in, such as the Western Pacific, overcoming that tyranny of distance means that we probably will need combat aircraft for longer ranges,” he said. A larger payload would also be vital in such scenarios because the jet will likely have to stay in the area of engagement for longer durations and have enough weapons capability to make an impact on enemy assets........
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Old 30th Aug 2016, 09:20
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F-35C Completes DT-III Ahead of Schedule 29 Aug 2016 CVN-73
"The F-35 Patuxent River Integrated Test Force (ITF) completed the third and final shipboard developmental test phase (DT-III) for the F-35C Lightning II aboard USS George Washington (CVN 73) Aug. 25 - one week earlier than scheduled.

The highly diverse cadre of technicians, maintainers, engineers, logisticians, support staff, and test pilots assigned to the Salty Dogs of Air Test and Evaluation Squadron (VX) 23 showcased their trademark test efficiency and effectiveness by completing 100 percent of the required DT-III test points during 41 flights logging 39.7 flight hours and featuring 121 catapults, 70 touch and go landings, 1 bolter, and 121 arrestments. The team also completed their previous two shipboard detachments early - DT-I aboard USS Nimitz (CVN 68) in 2014 ended three days early and DT-II aboard USS Dwight D. Eisenhower (CVN 69) in 2015 ended six days early. The Salty Dogs returned to Naval Air Station Patuxent River on Aug. 26."
https://www.f35.com/news/detail/f-35...ad-of-schedule
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Old 30th Aug 2016, 09:41
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LM GM Weekly Update 26 Aug 2016 Jeff Babione
F-35C DT-III
As the Edwards test team continues to knock it out of the park, the F-35C is wearing out the three wire on USS George Washington (CVN 73) for DT-III. Now finishing up their second week of action out at sea, the team is literally blowing through test points, surpassing minimum wind over deck and high wind over deck points up to 45 knots.

Those are very difficult points to meet and the team is doing an outstanding job of completing these crucial test points. The aircraft and team continue their impressive streak of 114 arrestments and zero bolters. If you add the 120 arrestments the pilots from VFA-101 completed last week during pilot carrier qualifications, the F-35C has accomplished an astonishing 234 arrestments without a single miss during this deployment....”
https://a855196877272cb14560-2a4fa81...te_8_26_16.pdf (0.74Mb)
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Old 30th Aug 2016, 11:20
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"the F-35C has accomplished an astonishing 234 arrestments without a single miss during this deployment....”

Interested to know what a normal rate would be?
Difficult to know if this means its an easy aircraft to land or exceptional pilots on the programme.
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Old 31st Aug 2016, 05:08
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I will look around for a 'normal rate' for which aircraft? I guess now that Hornet/Super Hornets are only around that would be it? USN LSOs keep precise detailed data about every pilot and every carrier landing (at the LSO school). More information used to be made available online however for several years now their monthly newsletter has not been made public so recent information is likely to be scarce indeed.

Otherwise pilots both test and squadron have been quoted often enough that the F-35C is an easy aircraft to carrier land. It is a 'three wire machine'. At first there are test pilots then come the F-35C instructor pilots of VFA-101 who have day qualified. Later when HMDS III becomes certified for ordinary night use onboard then they (instructors) will go back for night quals.
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Old 31st Aug 2016, 05:30
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This jargon filled explanation perhaps requires explanation of Case Recoveries and Rules to Live by - just say so.... otherwise the quote gives an idea of broad requirements.

COE/Blue Water Certification Paddles Monthly June 2011
"...What are Event Factor (EF) and Combat Boarding Rate (CBR)? Event Factor measures the ability for the flight deck and air wing to work together to maximize lethality and survivability. Here is how it is measured over the course of a launch and recovery: Event Factor = (Total # of Launches + Total # of Recoveries)/(Minutes Elapsed)...

...As for Combat Boarding Rate (CBR), it is calculated by the number of traps divided by the total number of “attempted‟ traps with 90% being the goal for Case I/II and 85% for Case III. Both metrics are related to each other due to the fact that a bolter obviously hurts both your EF as well as your CBR.

Historically speaking, it tends to be a bit harder for Carrier Air Wings to achieve their Combat Boarding Rate numbers than Event Factor. Squadron LSOs need to train your Ready Rooms to consistently shoot for a 55-60 second interval vice 45 seconds, be very disciplined in the pattern, and to safely get aboard on the first pass while not violating the “Rules to Live By.”"
http://www.hrana.org/documents/Paddl...lyJune2011.pdf [no longer available]
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Old 31st Aug 2016, 07:03
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Thank you for that.
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Old 1st Sep 2016, 03:38
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Some positives

F-35A continues fifth-generation tradition of air superiority against legacy aircraft > Hill Air Force Base > Article Display
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Old 1st Sep 2016, 07:04
  #9697 (permalink)  
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As a follow on to the USAF looking for a new fighter in service by 2030.....

The Looming Air Superiority Train Wreck

.........."The Air Force’s realization of its declining air superiority capabilities places America’s allies in an invidious position. With doubts now about whether the U.S. Air Force can be relied upon to win future near-peer air battles, American allies may need to reconsider their force structure plans and alliance relationships. This later aspect might be especially prominent if worries over revisionist state adventurism materialize.

An option for the allies might be to delay buying the current F-35 configuration aircraft until the U.S. Air Force’s intentions concerning new air superiority systems are clearer. At that time, allies might then be able to buy into a long-term robust air superiority solution, perhaps some element of a systems of systems that might include evolved F-22s or F-35s (if they were allowed access to these). This approach would perhaps allow them to remain operationally useful American allies past 2030 when at the moment it seems their value sharply diminishes............"
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Old 1st Sep 2016, 20:09
  #9698 (permalink)  
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Last ever unmanned QF-4 flight acted a target for an F-35 firing 2 x AIM-120, and survived. Some scepticism as to the claim it was supposed and the Mx were made to self-destruct.

https://theaviationist.com/2016/08/3...-and-survives/
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Old 1st Sep 2016, 22:37
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Lol that can't be right ORAC, we should ask a distinguished expert [on this very forum] to validate these preposterous claims of failure...

OyOyOy RN fleet defence with a pair of ASRAAMs on the outer pylons [if the wings dont rip off (lol btw)] way to go F35B.
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Old 2nd Sep 2016, 17:28
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Update 1:The reason for the QF-4 not being shot down is probably that the test was not a test of the AIM-120 missile’s ability to hit a target (something that has been proved in the past) but on the F-35’s ability to track the target and guide the AMRAAM until this reached the kill envelope. Once the missile starts self-guiding to the drone the test is accomplished and there is no need to waste a costy unmanned aircraft: the AIM-120 is directed to self-destruct before impact.
GR, did you bother to read the article? This is from the article, FWIW.
Is it fact or speculation? Don't know, but it makes a certain amount of sense.
Just out of curiosity, how much test flying and weapons testing have you done? Test programs are a thing of their own.
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