Navy's J-35 not suitable for carrier ops?
- Thread starter Ngrossman
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msmspilot
Well-Known Member
http://www.f-16.net/news_article4494.html
Hadn't heard about it, but this article seems to verify it.
Hadn't heard about it, but this article seems to verify it.
///AMG
Well-Known Member
What I heard was that the hook was basically pulled off the shelf, and didn't work due to the much shorter hook to main gear distance on the JSF. I can't imagine that this will be a show-stopper. Another issue if, I heard correctly, was with hook point strikes on the wires (ie the shoe at the end of the hook was also not rounded enough). This can cause premature parting of wires which is obviously bad news. EA-6B had a similar problem in early flight testing.
inigo88
Composite-lover
From what I've read and understand about aircraft prototyping (think HAVE BLUE, predecessor to the F-117, the Northrop YF-17, predecessor to the F/A-18, the YF-23, etc.) the company making the aircraft is sometimes putting a lot of their own money down and trying to build the thing as cheaply and with the most common off the shelf parts as possible.
In the case of the HAVE BLUE, Ben Rich talks in his book "Skunk Works" about how they took the engines from a T-2C Buckeye, the landing gear from a Northrop F-5, the fly by wire flight control system from the General Dynamics F-16, the most generic minimalist avionics imaginable and built it all using left over tools from the C-5 program.
I know the F-35 is well beyond its initial prototyping phase and has many sources of funding, but the generic tail hook may be a remnant of that 'buy off-the-shelf and jerry rig it all together so we can get the contract' type attitude.
Having to design a custom tailhook certainly wouldn't be a show stopper, just something they were probably trying to avoid doing to cut costs.
In the case of the HAVE BLUE, Ben Rich talks in his book "Skunk Works" about how they took the engines from a T-2C Buckeye, the landing gear from a Northrop F-5, the fly by wire flight control system from the General Dynamics F-16, the most generic minimalist avionics imaginable and built it all using left over tools from the C-5 program.
I know the F-35 is well beyond its initial prototyping phase and has many sources of funding, but the generic tail hook may be a remnant of that 'buy off-the-shelf and jerry rig it all together so we can get the contract' type attitude.
Having to design a custom tailhook certainly wouldn't be a show stopper, just something they were probably trying to avoid doing to cut costs.
From what I've read and understand about aircraft prototyping (think HAVE BLUE, predecessor to the F-117, the Northrop YF-17, predecessor to the F/A-18, the YF-23, etc.) the company making the aircraft is sometimes putting a lot of their own money down and trying to build the thing as cheaply and with the most common off the shelf parts as possible.
In the case of the HAVE BLUE, Ben Rich talks in his book "Skunk Works" about how they took the engines from a T-2C Buckeye, the landing gear from a Northrop F-5, the fly by wire flight control system from the General Dynamics F-16, the most generic minimalist avionics imaginable and built it all using left over tools from the C-5 program.
I know the F-35 is well beyond its initial prototyping phase and has many sources of funding, but the generic tail hook may be a remnant of that 'buy off-the-shelf and jerry rig it all together so we can get the contract' type attitude.
Having to design a custom tailhook certainly wouldn't be a show stopper, just something they were probably trying to avoid doing to cut costs.
The F-117 itself was built in the same way with off the shelf components.
And it's tailhook was problematic too, as was later found out, with the piston unit that extends it.
RightSeatGirl
KA'PLAH BITCHES!
Errr, tail hook on an F-117? I've never heard of there having been a navalized prototype version of the Nighthawk...Did this one get by me? Was the Navy at some point thinking of a carrier version?
PositionAndHold
Well-Known Member
It is a little known fact that Air Force land based fighters have tail hooks. The AF uses land based aircraft arresting systems. They don't stop like carrier arresting gear, it's takes about 1200 feet, depending on weight etc. It does however use a tail hook/steel cable combo. If one would try and land an F-16 on a carrier, it would simply rip the tail hook off the airframe. They are generally used during landing roll out or an aborted take off. I worked on these systems during my fours years of active duty.
The link is a quick over view of what some look like. The most common system is probably the BAK-12.
http://www.boeing.com/commercial/airports/faqs/arrestingsystems.pdf
The link is a quick over view of what some look like. The most common system is probably the BAK-12.
http://www.boeing.com/commercial/airports/faqs/arrestingsystems.pdf
Yes, we had tail hooks on the 117s I flew. No Navy version (though there was a proposed F-117N Navy version which was never produced), just a regular tailhook like most other USAF tactical jets. It's never regularly used, and for good reason, as explained below.
The 117s tailhook is located within the fuselage. In the pic below, the red outline on the aft rear end of the fuselage bottom is where it is located. That panel has detonation cord which is where the red outline is marked. Upon pressing the tailhook button on the lower-left part of the instrument panel, the det cord blows the panel off and the hook drops. Problem is, deploying the tailhook is a runway FOD nightmare with the panel parts everywhere, as well as a national security problem with the RAM coating parts that covered that panel now all over the runway too.
Don't feel bad RSG, there are likely a good number of things with the F-117 that got by you, and the rest of the public for that matter. Someday, I might be able to tell you more.....
Most military and joint-use runways have two separate aircraft stopping systems: arresting gear, and aircraft barriers.
Arresting gear is designed to be engaged by tailhook-equipped aircraft and consists of a wire strung across the runway at various points and either supported by rubber "donuts" designed to keep the wire about 2 inches above the runway surface (that's the case with BAK-6/9/12 and13 or E-27/E-28 at USN/USMC bases), or recessed in a slot on the runway and raised by remote control as needed (BAK-14). When engaged by an aircraft, the wires run out and are connected at each end to a box on both sides of the runway that contains the stopping mechanism. The stopping mechanism consists of brake pads on a caliper that engage a rotor at a certain rate, stopping the aircraft; or a hydraulic "water squeezer" (on BAK-6) that engages a piston pushing against water inside a tube for "hydraulic" stopping ability. On the airport diagram, the arresting gear is depicted as a one-or two-way arrows near the approach, center, and/or departure ends of the runway. One-way arrows indicate single-direction arrestment, two-way arrows indicate bi-directional arrestment ability. To see on an actual runway where these systems are located, they're marked by painted yellow circles across the runway at the cable location, as well as a lighted sign abeam each side of the system which is a lighted yellow circle on a black background, in normal airport-signage presentation.
See here where it's depicted:
http://www.fltplan.com/AwDisplayAppChart.exe?a=1
Aircraft barriers are located at the departure ends of the runway and are designed to either "catch" the aircraft's wings, or it's main landing gear. Older systems, such as the MA-1A, consist of a approximately 6 inch high wire hooked to a 2-foot recessed net that lays flat on the runway. As the aircraft passes into the overrun, it's nosewheel runs over the 6-inch high wire causing the 2 foot high net to spring-up and engage the main landing gear of the aircraft, bringing it to a stop in the overrun. Newer barriers, such as the BAK-15, are raised by remote control from the tower and consist of a 23 foot high net supported by stanchions on each side of the runway, similiar to those emergency barriers aboard aircraft carriers, that catch the aircraft's wings as the aircraft passes through it, and stops the aircraft in the overrun. On the airport diagram, the barriers are depicted as a vvvv looking symbol at the end of the runway. On the previous diagram, see the departure ends of runways 16 and 25.
Some military aircraft, such as the F-4, F-117, B-52, and some foreign versions of the F-16, still utilize drag chutes that are deployed on landing in order to shorten landing roll in normal ops, and as an abort aid for takeoff emergencies.
Other airports: ABQ has BAK-12/14, while TUS has BAK-12, BAK-12/14, and MA-1A MODified
PositionAndHold
Well-Known Member
The BAK-12/14 combo is what I have the most experience. Though if I remember at Hill AFB we had a 12/14 at each end, a straight 12 mid field and a BAK-9 just north of the south 12/14.
To add to what MikeD said, the cables only stretch the width of the runway. In the BAK-12, the cable is then attached to six inch wide nylon tapes that run thru a series of rollers and down a tube about a hundred feet to a barrier shack on each side of the runway. About 1500 feet of tapes are wrapped around vertically mounted spools. When the cable starts to move the down the runway, the tapes spin the spool. Attaced to either side of the spool is a B-52 brake assembly. The faster the the spool spins the harder the brakes are applied. The brakes are applied using a hydraulic accumulator. Once the aircraft is un-hooked, the barriers are rewound using small gas engines. I never thought 15 years ago I'd be explaining how a barrier works on the Internet.
There it is, more then anyone ever wanted or cared to know about AF arresting systems.
Clear as mud??
The tower had control of raising and lowering the 12/14, and during certain ops we strung the other ones manually.
It seemed whenever we had a navy squadron tdy, they couldn't go more then a day without taking a cable. We probably averaged about one to two engagements a month otherwise. It was definitely a fun job. The weird thing was barrier maintenance was assigned to Elecetrical Power Priduction ( Generator Mechanics). So while our main job was Generators, some one decided to stick us with the barriers.
Thing with the Navy is that with the way they pressure their tires, etc, on most of their tactical jets, their preference is to take a land-based arrestment in certain instances such as wet runway with a crosswind component. Even at USN shore bases, land-based arrestments of the E-27/28 gear is normal, and they cycle planes through in matters of minutes. Whereas the USAF treats any arrestment as darn-near a major emergency, with time measured in hours sometimes in order to reset the system in battery.
At every base I was at in my enlisted time, barrier maintenance never seemed to work weekends, so the fire department rescue truck crew was stuck with daily A-gear inspections, etc, during those times.
RightSeatGirl
KA'PLAH BITCHES!
Thanks for the info..I actually think I knew this now but had memory dumped it somewhere between Dos Equis case #5345 and #9876....
bkey79
Well-Known Member
Or the volleyball net bak-15
We had a problem with the touch screen/windows interface when a T38 at DLF called for barrier. I looked to see if that vid was uploaded, but couldn't find it. The net went up after the nose gear crossed then caught the right rear main and spun the T38 like a top. Pretty crazy to watch!
We had a problem with the touch screen/windows interface when a T38 at DLF called for barrier. I looked to see if that vid was uploaded, but couldn't find it. The net went up after the nose gear crossed then caught the right rear main and spun the T38 like a top. Pretty crazy to watch!
bkey79
Well-Known Member
At KDLF they were always down, unless called for. In 2005 we moved from the old tower/rapcon to a brand new tower/rapcon/wx building, and the new tower had a touch screen for lights and barriers, which didn't operate exactly as planned the first go around... Can't really speak for all bases, my 8 out of 9 years in the AF I was a RADAR guy...
///AMG
Well-Known Member
Yes and no. We don't carrier pressurize tires at the field, unless you are just referring to boat/CQ field divert ops. Fact is that the Hornet (which most USN/USMC tacair f/w ops are based on) is terrible in standing water and/or crosswind. I've landed it at NATOPS crosswind limits (ok a couple knots less) in driving rain. No standing water yet, but wet runway. Very sporty, jet just simply doesn't want to track straight, and above 100 knots you get some weird RSRI (rudder surface to rolling interface, basically the nice software logic that lets us forget we have rudder pedals 99% of the time) interaction when you try to hold aileron into the wind......our crosswind landing procedure is to land in a full crab, or to kick out half of it on touchdown when it is really significant. With standing water, this is a sure recipe for disaster, as you have already biased the jet towards the grass. Hence mandatory traps with standing water over 1/4 inch. I saw it a couple times at Miramar during big winter storms, and it was very controlled and quick. It didn't take more than about a minute to have a ready deck between traps. I think this is mostly due to the system differences between the E28 gear we have at all USN/USMC fields, and the older style chain gear and such that the AF sometimes operates. That and we are intimately familiar with doing fly-in arrestments due to the nature of our business.
Apart from the Hornet, which I remember you saying was squirrley with the type of landing gear it has, I remember that we always had to prep for USN jets taking land arrestments with wet/standing water and/or any crosswind component, as they run a different tire pressure during certain ops.....boat or something like that. Makes them more prone to hydroplaning.
Yeah, with the USAF, taking a cable is almost an hour runway closure. Granted, it's usually for an emergency aircraft, but even with an aircraft with no brakes and even if crash recovery gets it's towed off the runway quick, there's still alot of time taken to reset even modern arresting systems for us, as it's just not normal. In a normal arrestment.....runway overrun, wet runway at departure end, etc....something where there isn't an emergency with the jet; once the jet takes the cable, it has the ability to power up some and release itself from the cable as it rolls back after going to idle. Known as a "slingshot" maneuver. Problem is, only the F-15C (and maybe the E) and the F-4 are the only USAF jets that can actually retract their hook fully once lowered. F-16 can release the downside pressure and may come up a bit, but F-117 and others.....once it's down, it's down.
DLF used to keep them all the way up, as ATC used to as a normal thing; primarily to negate having the time it takes to raise itself once activated. Guess they finally changed that.
When I was at DLF 15 years ago, a T-37 was one of the last jets coming back at dusk one night. Some new approach lighting had been repaired, and tower asked the T-37 crew if they could do an opposite direction approach/low approach to check them out and judge how they looked. Unbeknownst to anyone, the RW 13C BAK-15 was in battery, as per the normal ops, and the T-37 made it's approach to 31C. On the low approach, the mainmounts of the T-37 snagged the top of the 23' tall BAK-15 net and slammed the jet into the ground right on the 31 numbers, where it burned up.