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F-35 INITIAL OPERATING CAPABILITY FACES DELAY

Defense Daily International:

The initial operating capability (IOC) for the F-35 Joint Strike Fighter (JSF) faces about a one year delay, approximately the same amount of time that the development program has slipped, according to a senior Navy official.

John Young, the Navy's assistant secretary for research, development and acquisition, told reporters last week that he couldn't discuss "precisely how much" IOC was delayed for the aircraft, but "I think the IOCs have slipped roughly commensurate with the one year slip" in the development program, he said. Under the original schedule, the first IOC was set for 2010.

F-35 is being developed in three versions by Lockheed Martin [LMT]...For the complete story go to: http://www.de


AND then theres this:

The U.S. Navy's unfunded priorities total $2.5 billion. The Navy would like $11 million to fix "known aircraft structural problems" in F/A-18 fighters. Navy officials said that failure to repair the problem could result in the grounding of 29 active forces aircraft in FY '05.

Which type of Hornets, is this another wing-drop problem?
Your link went to a German site.

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Which type of Hornets, is this another wing-drop problem?
Your link went to a German site.
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It's probably structuraly significant cracks and corrosion in the A-D varieties of F-18. You can't do much with $11 million though. It can't be that serious.

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airframe fatigue...

Hornets wear out quicker than Tomcats, you get what you pay for. While all aircraft suffer this problem over the course of their service life, the Tomcat was designed for more flight hours...Like I said before, cheaper is not always cheaper when you factor in all the variables.

would someone care to comment on frame fatigue for CAP vs. strike missions?

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

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would someone care to comment on frame fatigue for CAP vs. strike missions?

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I'd say for launch and recovery structure (nose & main gear, hook and keel) they are pretty close, but the strike missions tend to have higher launch and recovery weights so the strike missions are a little worse. The cat tow loads are bigger and so are the impact landing and hook loads. Maybe you can compensate for this by speeding up the ship a few knots (wear out the ship in place of the jet). For the up and away part, the strike missions are much worse for the wings, wing support structure and stabs, because they tend to do a lot of yanking and banking at high weights, low altitude and high speed. The CAP mission is a lot of smooth racetrack patterns so it's easier on things. If you want them to last, don't practice strike missions, or at least keep the gross weights down somehow, and don't operate them from ships.

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The CAP mission is a lot of smooth racetrack patterns so it's easier on things

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Oh yeah and way back on power. So you would normally have less AB cycles.

Toms had some nose gear problems within the last several years. Lost a few of them when the assembly departed while either trapping or on a stroke.

Jack

I wouldn't go so far to say that the nature of the 14's mission for 2/3rds of its service life is why the airframe has lasted longer. True strike missions are tougher on a jet than CAP, for a multitude of reasons, but the 14 is now also an all weather strike aircraft, as was the A-6...BOTH are longer hour airframes than the F-18, it was just part of their design criteria and capital investment. Both were designed from day one to be carrier warfare tactical aircraft, where the F-18 was not. The Tomcat was designed from the start, to endure into the early 21st century, this was part of the justification for the then record defense spending aircraft procurement program, pretty certain that ammount has now been surpased by other aircraft programs...BTW trap weights of the F-14 have alwas been heavier than the Hornet, a Tomcat can trap with all its ordanance (save a 6 Phoenix loadout) and the minimum required fuel as per NAVAIR regs, the Hornet would still have to drop some of its loadout into the drink to trap with the fuel nessasary for a safe fixed wing recovery.



Edited by - chadrewsky on Mar 11 2004 12:50 PM

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BOTH are longer hour airframes than the F-18, it was just part of their design criteria and capital investment...
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I have to disagree that the Grumman jets were designed as longer hour airframes. I don't think they had that as a design criteria. Even if they did have a high "flight hour" count for the original design, by now the actual usage would be unrecognizable to the predicted one thirty years ago. If they have virtue it is because a lot of effort has been made to find the hot spots and engineer economical repairs for them. Maybe the material selection was superior, and corrosion is held in check. I'm a little fuzzy on it, but I remember frantic activity to fix landing gear support bulkheads on the Tomcat way back in 1985. Also, the wings of the A-6E were definitely in crack trouble in the late 80's. That's why the ill conceived composite wings went forward. There might be alternative explanations for the airframe longevity too. Since both those jets were designed to be able to operate from Essex class ships, their catapult fly-away speeds and landing approach speeds were relatively low to start. Operating from C-13/Mk-7 Mod3 ships is delicate handling for them, well at least an improvement. The F-14 especially looks like an easy trap whenever I see promotional films of it, even though it is so big and heavy. The F-18, on the contrary, always looks like the proverbial crash landing (does anyone else agree?). Nothing helps out the lowly stress analyst of a naval aircraft like slow speeds around the ship. I hate to give the other group credit, but the aerodynamic design (span, sweep, area, flap geometry, etc) of the F-14 and the A-6 are things of beauty to the loads and stress analysts. They deliver slow speeds around the ship.

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well...You are better versed at theory end of this than I am...But, I have read from many sources that the 14's and the A-6's were/are more robust platforms...Both aircraft have served for 30+ years....I think its concievable to believe that a high dollar aircraft is designed to endure a longer service life. I have also read that the F-18 has suffered more fatigue, and worn out quicker than anticipated...No matter how the design was "beefed up" to accomodate its carrier warfare requirements, it was not designed for that from day one...

As I recall the original A-6 proto didnt need cats or wires to operate from a carrier, remember it had the tiltable tail pipes that pivoted with the flaps. The absolute smoothest trap I ever saw was an A-6 it just barely touched the deck, a total greaser of a landing.

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

On the flip side the F-8 and A-5 came in hot....forget the landing speed of both, Jack would remember for it was in his realm of service....But man, talked about controlled crashes...

Just for the record, I think the F-18 looks bad to the bone on a trap, not the grasping for lift, flaps flying, turkey appearance of the F-14.

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On the flip side the F-8 and A-5 came in hot....forget the landing speed of both, Jack would remember for it was in his realm of service....But man, talked about controlled crashes...

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Lower approach speed and less crashes is the basic rule. Tis reason the S-3s are pretty solid at the boat along with the A-6s.

A-3s were the highest( might be wrong on speed) approach speeds and weights. Think they were in the 145knot range plus for the A-3 and A-5s. F-4s were damn close too. Then the F-8s were a lil slower, but O man they always had some problems.

Tomcats had to be careful on approach with their engine limitations. Lost a few over that. Recall the furor over that first female Tomcat pilot that crashed at the boat.

They were building Toms and Intruders until the early 80s. Doubtfull any A-6 ever lasted 30 years, with the exception of the EA-6Bs. Marines ran A-6s a long time too.

S-3s at first had problems at the boat. Lockheed hadn't built a bird for the boat in a LONG time. Pilots got to far behind on the power curve and couldn't spool up. They finally added some funky spoiler system, it was activated by a switch or button on the stick or throttle. You hit the puppy and it brings you down the glide slope, vice reducing power.

I still find it funny on the Hornets, it's a computer controlled cat shot and the pilot is just hanging on. Look at their right hand hanging onto the grip. Watch the rudders deflect inboard. Lowers the stall speed a tad.

Jack

I've heard the Hornets are the easiest of all the planes to land, maybee due to the FBW.

saw a disscution on a newsgroup and was wondering, does the E-2C have enough power to do a 1 engine out wave-off during the landing sequence? how late can they wait and still make it?

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

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I've heard the Hornets are the easiest of all the planes to land, maybee due to the FBW.

saw a disscution on a newsgroup and was wondering, does the E-2C have enough power to do a 1 engine out wave-off during the landing sequence? how late can they wait and still make it?

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Probably so on the Hornet. E-2s should be fine, if you catch the rudder quick enough. They have 2 T-56s on them. On the coolie hat on the yoke, we had rudder trim along with elevator, vice the norm of having aileron. How close before you can safely wave off? Farther is better. You still have to feather the motor and take care of the boldface items, to ensure a wave off.

The most critical 2 motor bird, was the old S-2 with the radar on the roof. That puppy with one motor out, you needed to have the overhead hatches closed to maintain flight with one motor.

Jack

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I'd say for launch and recovery structure (nose & main gear, hook and keel) they are pretty close, but the strike missions tend to have higher launch and recovery weights so the strike missions are a little worse. The cat tow loads are bigger and so are the impact landing and hook loads. Maybe you can compensate for this by speeding up the ship a few knots (wear out the ship in place of the jet). For the up and away part, the strike missions are much worse for the wings, wing support structure and stabs, because they tend to do a lot of yanking and banking at high weights, low altitude and high speed. The CAP mission is a lot of smooth racetrack patterns so it's easier on things. If you want them to last, don't practice strike missions, or at least keep the gross weights down somehow, and don't operate them from ships.

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Ground loads are significant contributors to fatigue damage. On the ground, fuel in wing tanks and wing stores stress the wing like negative g. Get the wings flexing while you are taxying and the wing feels big negative g. Loaded aircraft miss out on most of this during carrier ops. Obviously, all wings experience negative g stress when landing, due to their inertia. Landing with a lot of fuel in wing tanks and all your wing stores does a lot of fatigue damage. This can be minimised by landing with fuel in the fuselage tanks only, or in the inboard wing tanks only if you can't get all the fuel into the fuselage.

Fuel in wing tanks, and wing stores, actually reduce the fatigue damage done to the wings, as they relieve (counteract) the lift loads on the wings and reduce the shear force and bending moment at the wing roots (the most highly stressed part of the aircraft structure).

Of course, having a light aircraft and not pulling g reduces fatigue damage also.

To illustrate: your aircraft weighs 50,000lb; you have 15,000lb of fuel, 10,000lb of fuel and the structure of each wing weighs 1,000lb.
Ignoring any lift effect from the fuselage, each wing has to provide 25,000lb of lift in straight and level flight.

If all the fuel and stores are carried in and under the fuselage, the shear force at each wing root, in straight and level flight, is 25,000lb minus the 1,000lb weight of the wing structure itself ie 24,000lb.

If all the fuel and stores are carried by the wings, the shear force at each wing root, in straight and level flight, is 25,000 minus (1,000 + 15,000/2 + 10,000/2) = 11,500lb.

Pull 6 g: the wing root shear load is 144,000lb for the first aircraft and 69,000lb for the second.

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Watch the rudders deflect inboard. Lowers the stall speed a tad.

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A guy who worked in the project office in the US when the RAAF first signed up to buy Hornets told me that the rudders were made to deflect inboard to make the aircraft rotate earlier. Without this subtle intervention by the flight control computer, the aircraft could not rotate by the specified 105 knots.

well the rudders tow in to act as speed brakes, since the speed brake between the vert stabs is inactivated due to buffeting as I recall.
thanks for the info guys.

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

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A guy who worked in the project office in the US when the RAAF first signed up to buy Hornets told me that the rudders were made to deflect inboard to make the aircraft rotate earlier. Without this subtle intervention by the flight control computer, the aircraft could not rotate by the specified 105 knots.


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I think this is correct. Deflecting the rudders symmetrically has the effect of a traditional elevator because of the cant angle of the fins. It can give some help to the stabilator when it is running out of power (near stall), such as during rotation.


Edited by - a10stress on Mar 14 2004 5:28 PM

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well the rudders tow in to act as speed brakes, since the speed brake between the vert stabs is inactivated due to buffeting as I recall.
thanks for the info guys.
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The F-22 uses the rudders in a "speedbrake mode" too. It saved having to have another actuated door so we got rid of a real speedbrake in 1992. The F-22 flight controls all deflect in a kind of dance to keep the pointy nose forward. Delecting just the rudders pitches up the F-22 also so the other sufraces are moved to compensate. You need quite a bit of rudder to get enough drag though. It really loads those razor blade thin fins quite a bit. It has caused some anxiety for us.

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S-3s at first had problems at the boat. Lockheed hadn't built a bird for the boat in a LONG time. Pilots got to far behind on the power curve and couldn't spool up. They finally added some funky spoiler system, it was activated by a switch or button on the stick or throttle. You hit the puppy and it brings you down the glide slope, vice reducing power.

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Vought (the Lockheed team mate) was giving them credibility in the carrier compatibility area. I know that main gear has unique details but it looks kinda like F-8, A-7 doesn't it? The F-14 has those glide slope control spoilers too. When they are in use they are partially open all the time so you can go up or down on the glide slope with very little pitch attitude change (close 'em and you go up, open 'em more and you go down). Nice idea but I wonder if it is worth the higer approach speed. Does anyone know if it works well?

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I have a pic of the F-22 on the ground, head on into the camera with those rudders deflected. They are big as barn doors!!

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

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[Vought (the Lockheed team mate) was giving them credibility in the carrier compatibility area. I know that main gear has unique details but it looks kinda like F-8, A-7 doesn't it? The F-14 has those glide slope control spoilers too. When they are in use they are partially open all the time so you can go up or down on the glide slope with very little pitch attitude change (close 'em and you go up, open 'em more and you go down). Nice idea but I wonder if it is worth the higer approach speed. Does anyone know if it works well?


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I first learned of the S-3 mod from an IP. His good buddy had died in a Viking accident in 74 or so. So they came up the spoiler mod. I can't recall if he was at the boat or FCLP. Think he stalled it in and was near idle. Couldn't spool it up. Never heard anything else bad about the Viking after that. Except it wasn't real swift as a sub hunter. Not that fast at cruise either. Think for long range cruise they were truing about 360KTAS.

I gotta think of the gear. Generally, using something that is already working should be kool. A-7s were a pretty tough bird.

Jack

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S-3s at first had problems at the boat. Lockheed hadn't built a bird for the boat in a LONG time. Pilots got to far behind on the power curve and couldn't spool up. They finally added some funky spoiler system, it was activated by a switch or button on the stick or throttle. You hit the puppy and it brings you down the glide slope, vice reducing power.

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Vought (the Lockheed team mate) was giving them credibility in the carrier compatibility area. I know that main gear has unique details but it looks kinda like F-8, A-7 doesn't it? The F-14 has those glide slope control spoilers too. When they are in use they are partially open all the time so you can go up or down on the glide slope with very little pitch attitude change (close 'em and you go up, open 'em more and you go down). Nice idea but I wonder if it is worth the higer approach speed. Does anyone know if it works well?


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It works very well. The purpose of it is also to help match the Pitch and Roll of the Carrier.In high Sea States that are on the edge of fouling recovery operations. The best trap is a 3 wheel Contact. Their are many reasons for this. The heavy Decent rate is neccesary to prevent balooning over the deck, and entering a stall condition. As the Old Joke in the Fleet went. "Flairing on landing is like squating to pee"

"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

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. The heavy Decent rate is neccesary to prevent balooning over the deck, and entering a stall condition. As the Old Joke in the Fleet went. "Flairing on landing is like squating to pee"

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LOL, took me a long time to learn to flare. Just bang the puppy down, max power, and you either trap or bolter.

They do add pressure to the tires for carrier ops. Coming back from the boat, with higher pressure tires, you were suppose to flare a tad for landing.

Back in the recip days, they gave the famed cut signal. I bet those that ended up transitioning to jets and angled decks. Had a helluva of a time adding max power when they were trapping.

Jack