JF F4F Wildcat Tailhook Settings?
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Thread: JF F4F Wildcat Tailhook Settings?

  1. #1
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    JF F4F Wildcat Tailhook Settings?

    Need some help please. I cannot get the Wildcat aboard without nosing over. I can catch the cable 99% of the time but then nose over. I've tried adjusting all 3 -- distance aft, length, and height, in differing combinations adjusting in increments of 0.5 but haven't been able to find a working combination.

    As always, your help will be greatly appreciated.

    Stock settings:
    // Original Tailhook Settings
    //[TailHook]
    //tailhook_length = 4.000
    //tailhook_position = -16.000, 0.000, -1.000
    //cable_force_adjust = 1.000000

    Steve
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  2. #2

    Re JF Wildcat tailhook

    you might try this it works for me:

    Locate this section in the Aircraft.cfg.

    [TailHook]

    Delete the whole section = 4 lines.

    copy paste this replacement in its place,


    [TailHook]
    tailhook_length = 2.50
    tailhook_position = -20.100, 0.000, -0.500
    cable_force_adjust = 2.0

  3. #3
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    Quote Originally Posted by llanning08 View Post
    you might try this it works for me:

    Locate this section in the Aircraft.cfg.

    [TailHook]

    Delete the whole section = 4 lines.

    copy paste this replacement in its place,


    [TailHook]
    tailhook_length = 2.50
    tailhook_position = -20.100, 0.000, -0.500
    cable_force_adjust = 2.0
    Thank you llanning08. Will definitely give it a try. Iíll let you know how it works for me.
    Duckie

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  4. #4
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    .... Iíll let you know how it works for me...

    Sorry to report it didn't work. I was unable to catch a wire after many tries. I lengthened the hook in 0.1000 increments up to 3.000 when i began catching wires but the nose over was still there. I'll try some more tomorrow.

    Thanks,

    Steve
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  5. #5
    Make sure that when you trap, you have the right sink rate, and, in particular, the right AOA for the plane you're flying.

    Also, make sure the WOD is correct for the particular plane you're in, and that you are right on the centerline.

    Having said all that, you can try lowering the cable_force_adjust = 2.0 value. Try taking it down to 0.5. That's probably too low, but you can then slowly work it up from there until it stops the plane, but doesn't nose over.
    Second, another thing to try is lowering the
    tailhook_position = -16.000, 0.000, -1.000 vertical value, the third value following the equals sign. Take it down to about 1/2 the value of the main gear's contact point vertical value. You may need to adjust the tailhook_length = 2.50 value until the tail hook is about the same vertical value as the mains gear's contact point vertical value. If the mains contact point vertical is, for example, -5.00, make the tail hook's vertical position -2.50, and the length is 2.50. If you lower the tail hook's vertical position another 0.5, to -3.00, try it, and slowly raise the length a bit. Make it, for example, 2.25, and see if that works.

    Finally, thy moving the
    tailhook_position = -20.100, 0.000, -0.50 longitudinal position, the first value after the equals sign, farther aft. Try -25.00. Be careful though. You want to make certain the longitudinal position is actually aft of the plane model's center point.
    Check the position of the lights somewhere near the tail's vertical fin in the [lights] section. If the light's longitudinal position is a positive number, make the tail hook's position positive, and keep making it more positive, not more negative.
    Or check the [
    Views] section, which is the pilot's eyepoint. See where it is relative to the plane model's center point. Does it make the plane's center point look like it's on the tip of the plane's nose, or is it very near the main gear's longitudinal position, making somewhere near the plane center of gravity, ie: near the middle of the wing's chord.
    Once again, the whole point is to ensure that the tail hook's longitudinal position is AFT the center point. If it seems to be forward of the center point, it can make all kinds of interesting problems.

    Hope something in all my rambling helps a little...
    Pat☺
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  6. #6
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    Thank you Pat. I finally got it consistently coming aboard last night but it wasnít pretty. This little roadster really loves to float and the throttle needs the tenderest of touches or its off like a rocket. It Needs some more adjusting and your explanation of the elements involved will certainly be useful. Not at my flying machine or Iíd post up the settings I ended with last night. Iíll do that at my next adjustment session later this evening.

    Thanks again Pat, and thanks to llanning08 for giving me a better starting point than I initially was using.

    Steve
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  7. #7
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    OK. Here's the best I could get it for now. I can catch a wire 99% of the time, no nose overs or wing dips. The tail comes up to about center line but then settles quickly to the deck.

    [TailHook]
    tailhook_length = 2.100
    tailhook_position = -21.000, 0.000, -1.25
    cable_force_adjust= 1.500

    Thanks for the help you guys.

    Steve
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  8. #8
    Glad I could be a little help. Remember, consistancy is the key to good traps. That and the right AOA for the plane's weight.

    Have fun!
    Pat☺
    Fly Free, always!
    Sgt of Marines
    USMC, 10 years proud service.
    Inactive now...

  9. #9
    Quote Originally Posted by PhantomTweak View Post
    Make sure that when you trap, you have the right sink rate, and, in particular, the right AOA for the plane you're flying.

    Also, make sure the WOD is correct for the particular plane you're in, and that you are right on the centerline.

    Having said all that, you can try lowering the cable_force_adjust = 2.0 value. Try taking it down to 0.5. That's probably too low, but you can then slowly work it up from there until it stops the plane, but doesn't nose over.
    Second, another thing to try is lowering the
    tailhook_position = -16.000, 0.000, -1.000 vertical value, the third value following the equals sign. Take it down to about 1/2 the value of the main gear's contact point vertical value. You may need to adjust the tailhook_length = 2.50 value until the tail hook is about the same vertical value as the mains gear's contact point vertical value. If the mains contact point vertical is, for example, -5.00, make the tail hook's vertical position -2.50, and the length is 2.50. If you lower the tail hook's vertical position another 0.5, to -3.00, try it, and slowly raise the length a bit. Make it, for example, 2.25, and see if that works.

    Finally, thy moving the
    tailhook_position = -20.100, 0.000, -0.50 longitudinal position, the first value after the equals sign, farther aft. Try -25.00. Be careful though. You want to make certain the longitudinal position is actually aft of the plane model's center point.
    Check the position of the lights somewhere near the tail's vertical fin in the [lights] section. If the light's longitudinal position is a positive number, make the tail hook's position positive, and keep making it more positive, not more negative.
    Or check the [
    Views] section, which is the pilot's eyepoint. See where it is relative to the plane model's center point. Does it make the plane's center point look like it's on the tip of the plane's nose, or is it very near the main gear's longitudinal position, making somewhere near the plane center of gravity, ie: near the middle of the wing's chord.
    Once again, the whole point is to ensure that the tail hook's longitudinal position is AFT the center point. If it seems to be forward of the center point, it can make all kinds of interesting problems.

    Hope something in all my rambling helps a little...
    Pat☺
    Hi Pat,

    I've been trying to adjust the RAZBAM AD-5N so it doesn't tip over when trapping. I think I'm close, it stops and sits for a second, but then slowly tips on its nose with the parameters I've chosen at the moment.

    I used ModelConvertX to figure out about where the tailhook would be when it catches.

    Here's the contact points for the gear, tail is 0, main gear are 1 and 2

    point.0=1, -21.5, 0.00, -4.1, 2165, 0, 0.27, 40.0, 0.25, 8.80, 0.65, 5.00,5.00,0.00,0.00,0.00
    point.1=1, 1.03,-7.41, -8.475, 2165, 1.00, 1.2, 0.0, 0.9, 3.50, 0.65, 5.00,5.00,2.00,0.00,0.00
    point.2=1, 1.03, 7.41, -8.475, 2165, 2.00, 1.2, 0.0, 0.9, 3.50, 0.65, 5.00,5.00,3.00,0.00,0.00

    The tail hook would be at 27.75, 0, -4.25 if the tailwheel is just off the deck when it catches.

    so my latest parameters have been (commented lines are what it came with):

    [TailHook]
    //tailhook_length=6
    //tailhook_position = -16.74, 0.0, -1.62
    tailhook_length=4
    tailhook_position = -27.74, 0.0, -1.92
    cable_force_adjust = 1.0

    While I'm certainly hoping for suggestions for fixing this plane, I'm thinking I really want to understand how these parameters work so I can use ModelconverterX to determine them more easily and accurately.

    Is tailhook position the catch position or the pivot position?
    What does the length signify, the length of the tailhook, or the vertical position from the pivot to the catch position, or some vertical distance from the catch position?

    Do I set the position of the tailhook at the pivot, and then set the length of the tailhook as the length of the hook, and FSX will take care of the rest?
    In this plane, the contact points are relatively correctly positioned with respect to where the wheels sit on the model (I know that's not always the case).

    I'm going to try the pivot position and calculate the length of the tailhook as the length of the tailhook and see how that works.
    Last edited by FlyingsCool; May 17th, 2020 at 10:19.

  10. #10
    So... I've gotten this combination to work occasionally. Basically moved the pivot down a foot from where it is on the model and shortened the tailhook by a foot.

    But it seems my main issue is I'm coming in with my tail too high... But how do you see the deck to land if you come in with the tail lower?

    [TailHook]
    tailhook_length=4
    tailhook_position = -23.0, 0.0, -2.0
    cable_force_adjust = 1.00


    If anyone is interested, here's a slideshow of me landing on deck, pretty sure it tipped this time.

    https://imgur.com/gallery/ODmrFc1

  11. #11
    I take it back, just did as three point a landing as I could, 75 knots at touchdown, and the tail still bounced. I did try lowering the rear tailwheel by 0.2. Doesn't seem to have helped.
    It almost pulled it back down, but the plane shouldn't be tipping as much as it does, anyway.

    Maybe what I really need to do is create an AI carrier instead of trying to land on a stationary carrier. I did set the wind over the deck at 16 knots.

  12. #12
    Maybe what I really need to do is create an AI carrier instead of trying to land on a stationary carrier.
    Yes, absolutely.
    Place the carrier, set it to moving forward. Then, if you can find it, figure out the correct Wind Over the Deck, and adjust the sim's weather settings accordingly. When in motion, IIRC, the carrier is moving at 20 or 25 kts, so you adjust the weather accordingly. This number can be changed, if necessary, to get the WOD correct.

    A trick, or correct procedure, actually, the tail-draggers used to be able to see the deck during landing, was to make a loooong, sweeping, left turning, approach. They would cross the wake very shortly before touchdown, and watch the LSO for the final direction, sink rate and so on. Sadly, there is no real, practical way to make an AI LSO do the paddle waving they did back in those days. Best way is to watch the meatball. It not really realistic to have a meatball system on the older, straight deck, carriers, but it's the best way to have a sort-of, kind-of, simulated, Paddles officer.
    Alternatively, you can pop up a small, locked-spot view so you can see the plane relative to the deck, of the final little bit of the approach.

    Finally, as to the [tailhook] settings: to get it to stop tipping so much you can decrease the cable force= setting, as well as moving the tailhook position a bit further aft. Remember, this is in the aircraft.cfg, not modelconverterX. This won't change anything visually on the plane, just the way the sim does it's calculations. ModelConverterX can change the visual model, but not the sim's calculations about the tailhook. That's the aircraft.cfg settings. So you can wind up with settings that would be visually absurd, but are what's necessary to make the plane land correctly. Does that make sense?

    Good luck!
    Pat☺
    Fly Free, always!
    Sgt of Marines
    USMC, 10 years proud service.
    Inactive now...

  13. #13
    Quote Originally Posted by PhantomTweak View Post
    Yes, absolutely.
    Place the carrier, set it to moving forward. Then, if you can find it, figure out the correct Wind Over the Deck, and adjust the sim's weather settings accordingly. When in motion, IIRC, the carrier is moving at 20 or 25 kts, so you adjust the weather accordingly. This number can be changed, if necessary, to get the WOD correct.

    A trick, or correct procedure, actually, the tail-draggers used to be able to see the deck during landing, was to make a loooong, sweeping, left turning, approach. They would cross the wake very shortly before touchdown, and watch the LSO for the final direction, sink rate and so on. Sadly, there is no real, practical way to make an AI LSO do the paddle waving they did back in those days. Best way is to watch the meatball. It not really realistic to have a meatball system on the older, straight deck, carriers, but it's the best way to have a sort-of, kind-of, simulated, Paddles officer.
    Alternatively, you can pop up a small, locked-spot view so you can see the plane relative to the deck, of the final little bit of the approach.

    Finally, as to the [tailhook] settings: to get it to stop tipping so much you can decrease the cable force= setting, as well as moving the tailhook position a bit further aft. Remember, this is in the aircraft.cfg, not modelconverterX. This won't change anything visually on the plane, just the way the sim does it's calculations. ModelConverterX can change the visual model, but not the sim's calculations about the tailhook. That's the aircraft.cfg settings. So you can wind up with settings that would be visually absurd, but are what's necessary to make the plane land correctly. Does that make sense?

    Good luck!
    Pat☺
    Oh, absolutely. What I did was create a fake couple of contact points in ModelConvertX to determine the location of the pivot and where the end of the tailhook was to get a real geometric sense of what the numbers in the tailhook parameters mean. I was hoping that setting it to proper geometric conditions would work, or at least get close. But I still don't quite get exactly what those numbers mean? Is the tailhook_position the pivot?

    What does cable force adjust mean? And why would a higher number make it more likely to tip a plane? With a lower cable force, will the plane travel further down the deck after it catches a wire?

    The tipping of course seems to imply the CG of the plane is too high relative to the axis about the wheels. So I don't know how to get the tailhook to resist that moment appropriately. I am getting that tail down just before touchdown, so it's something about the force vectors involved here. Maybe raising the tailhook_position would help to get it above the CG?

    I'm thinking out loud now, somehow the force vector of the tailhook and cable has to be greater than the momentum of the CG about the wheels. But I don't know anything about the physics of how FS is applying the force of the cable over time.

    I've notice people keep making short tailhooks. At some point, the tailhook won't catch the wire if it's too short?, or is the wire a vertical plane as far as FSX is concerned. But a shorter tailhook would increase the angle of the tailhook from the pivot to the deck, and maybe get it to shoot over the CG, thereby creating the proper moment. But I'm just guessing at the physics here as I don't know exactly what the tailhook parameters mean.

  14. #14
    I was hoping that setting it to proper geometric conditions would work, or at least get close. But I still don't quite get exactly what those numbers mean? Is the tailhook_position the pivot?
    Yes, to be short. The position IS the location of the pivot. Having said that, the geometry of the flight model, including the position of the tailhook pivot, and the visual model created with ModelConverterX, are two entirely different animals. If you want to get a visual idea of where the tailhook positions are, use a light in the [lights] section, mot a point of some sort in MCX. Match the light's position to the tailhook position, and load the plane into the sim at night, so you can see the light. No pun intended.
    If you look, the tailhook's vertical, and horizontal (side-side), should be just about where the main gear hits the reference point.

    point.0=1, -21.5, 0.00, -4.1, 2165, 0, 0.27, 40.0, 0.25, 8.80, 0.65, 5.00,5.00,0.00,0.00,0.00
    point.1=1, 1.03,-7.41, -8.475, 2165, 1.00, 1.2, 0.0, 0.9, 3.50, 0.65, 5.00,5.00,2.00,0.00,0.00
    point.2=1, 1.03, 7.41, -8.475, 2165, 2.00, 1.2, 0.0, 0.9, 3.50, 0.65, 5.00,5.00,3.00,0.00,0.00

    In this case, the vertical position should be -8.5, roughly, obviously the side-side should be 0.0 . The tailhook Length should be about enough for the hook it's self to reach the deck, ie rest on the deck, with the plane at the correct AOA for landing. I don't have the stats on that particular plane, so I can't say what the correct AOA is. Let us say, though, just for example, the plane's correct landing AOA on the carrier is 4į. All you need to do now is a little trig to see how long the hook needs to be to catch the wire. Make a right triangle, with the three vertices as the pivot point 8.475, the main gear's attach point 8.475 units (feet, meters, inches, whatever) below the reference, as one point, and solve for the third point. That's one way to get a good starting point for it.
    Personally, I generally place the pivot point about 1/2 way down the main gear length, and leave it there. So the tailhook vertical position would be about -4.25. Then, because it's easy, make the length about 4.5, give or take. Gives it enough to actually slide across the deck to grab the wire. It's a good start. Then place the plane at landing AOA, and see if the hook portion of the tailhook IS touching the deck. It should be. If not, make it 0.5 longer, and check again. The trick is to be in slew mode so you can hold the plane at the right AOA.
    The HORIZONTAL position of the hook is a whole nother thing. Start with it about the position of the tail wheel, -21.5. Make sure you keep it behind the reference point, ie a negative value in this case. IF the plane slews off to one side or the other, every time you land, even if you land perfectly on the centerline, move it farther aft. 10 feet, 4 feet, whatever. Move it until the plane no longer slews side-side on landing.
    Do a number of landings, to ensure you are dead square on the centerline, for each new position. It should be far enough that the plane doesn't slew and tip when you land dead square on the centerline, but it does slew and/or tip, when you're OFF centerline on landing. Too far aft, it won't slew/tip when you're off centerline. Not far enough, it will slew/tip when you're ON centerline. You can do this all fairly easily. Set the plane, in slew mode, a short distance aft/above the boat. Make it far enough that you get to flight speed, in landing configuration and weight. Once all your plane's parameters are in tolerance, just hit save. Now you can re-load the plane, and make a landing. Then again, and again. You see what I mean.

    As to the cable force: You want it just high enough to stop the plane short of the edge of the deck. If it's too high, the cable will yank too hard on the plane's structure, damaging it. Not high enough, the plane will slide off the edge of the deck, causing a crash. You should set this parameter after you get ALL the rest of them set properly.

    If you want a pretty good example, if I may say so, look at the tailhook section of the FSX BA F/A-18C. You can find it on their forums. If you like, I can post the link to the current plane, or I can post the contact points and tailhook sections here for you. By the way, you need to have the parameters of the contact points for the gear correct so that they support the plane properly during a Navy landing. You keep the same sink rate all the way to the deck. You do NOT flare. You fly it all the way down onto the deck. So the landing gear parameters need to be correct to support the plane properly during a landing. Without that, everything else won't function correctly, you see? That's settings 9, 10, and 11, counting as the first parameter after the equals sign is 1.

    Finally, the Flaps settings must be correct to allow the plane to fly at the correct speed and sink rate to make the plane land on the carrier correctly.

    You can see, a lot of things feed into all this, other than just the tailhook settings.

    Does this help at all?
    Pat☺
    Fly Free, always!
    Sgt of Marines
    USMC, 10 years proud service.
    Inactive now...

  15. #15
    Perfect. Exactly the info I needed. Thank you.

    Yeah, issue with using the F-18 is it's tricycle landing gear, while the Skyraider is a taildragger. But I get it, and I hadn't considered the AOA on landing. I'm still working on that. I had done my trig calcs in the sitting postion, not in the flying AOA position on landing.

    I only have the POH for an AD-4, but I'm imagining the performance characteristics aren't too different for the AD-5N, and I'm still searching for an AD-5(N) (and W, too) POH. I do have Navair 00-110AA1-2 Standard Aircraft Characteristics, so that has a little corroborating info for use to compare to the AD-4 POH.

    One of the issues I have, too, as you noted - I find myself bouncing off the deck. I've got the velocity decent I think, between 70 and 80 knots, but I'm still working on how to get the correct sink rate apparently. I wonder also if I need to somehow adjust the compliance of the landing gear as well. I'm not exactly sure how long the stroke of the gear should be, but I do know that starting with I think it was the AD-4, they added 14" of stroke to soften the landing; I'm imagining it's got to be at least 24". I see in the aircraft.cfg the static compression is 4". I realize that's not the value I'm looking for, but I'm imagining the total stoke may be set too short. I need to figure out how to figure that out.

    Oh, and I was setting load-out to two crew and 30% main fuel and zero aux tank for landing tests.

    One thing that's a little annoying about the plane is that it gets up to 200 knots nearly instantly in clean cfg at sea level. That can't be correct.

    Edit: Oh, I forgot that tidbit, no flare. I've been flaring a bit to get the tail down just before touchdown so I can see the deck on approach. Think I'll look for some Skyraider deck landings on YouTube
    Last edited by FlyingsCool; May 18th, 2020 at 14:54.

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