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F14B Fly by wire


JRM

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F14B Fly by wire

 

Indeed, no idea how it is in the real tomcat. At low or high speeds or if it even makes a difference. Unlike in my glider, they do have hydraulics. They could make it as light as they want, I just highly doubt they made it super light and I would expect them to make it so its light at low speeds and a lot harder at high speeds. Well, even if they dont vary the hydraulic power, the aerodynamics would do that anyhow.

The horizontal tails pivot around the aerodynamic center so theoretically it takes the same force to move them at any speed. And the roll spoilers are technically FBW so none of their forces reach the stick, either.

 

That said, jet fighters with non-FBW controls tend to have a bob weight that increases stick force with increase in G rather than speed. With that in place it should be very difficult to over stress the plane with a smooth pull. I’m curious, though, if a sudden yank defeats the system because you’re moving the stick faster than G onset...


Edited by r4y30n
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The horizontal tails pivot around the aerodynamic center so theoretically it takes the same force to move them at any speed.

 

I have to doubt that. If they are exactly at the aerodynamic center, there would be no natural pitch stabilisation and not even an aerodynamic centering force on the stick. In some flight regimes that might even reverse and you would get an unstable aircraft with a stick that wants to pull forward if it noses over.

 

They may be relatively close to the center to keep forces manageable even when air hits them at mach 2, but they will be positioned so that the airflow pushes them towards neutral and if there is any such force, its strength will depend on airspeed (unless countered by hydraulics).


Edited by Vertigo72
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I've managed to rip them, but I was doing it on purpose to see what the damage model is like by going as fast as possible and then pulling back, I did it once, it's the only time it's happened to me.

 

In general it's not a great idea to be yanking the stick all the way back in anything, it's only good for haemorrhaging energy and breaking stuff, unless you have a fancy FBW to the tune of F-16 and the F/A-18C.

 

I guess the only way to address it is to get a FFB joystick, as presumably the faster you're going, the more force you need to deflect the stick, or just use stiffer centring springs if possible.

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I guess the only way to address it is to get a FFB joystick, as presumably the faster you're going, the more force you need to deflect the stick, or just use stiffer centring springs if possible.

 

I have one. There isnt any noticeable difference in centering force that changes with speed. Even on the ground, standing still, the stick is about as firm as it is at mach 1. Same when you stall out. Dont know how realistic that is, I would expect the stick to be pretty limb standing still or stalling but then I only have limited RL experience in 1970s navy jets. In DCS its only the trim that affects the stick force (moving the center position) and some vibrations when stalling or at high AoA.

 

Regardless if the stick centering force really changed with speed or or AoA or not in the real tomcat, two things Im pretty sure off:

- I bet F14 pilots couldnt pull 20g and snap their wings with 2 fingers on the stick when they sneezed.

- They would have noticed that g load, and loooong before it snapped their wings. 10+G is kinda hard to not notice.

 

And that is the real issue. It cant be solved 100% realistically, until we get gravity modification devices. But IM all for at least some visual feedback to let pilots know what it is they cant feel, and I dont think its crazy or cheating to allow a stick force simulation setting to slow down stick movements if in reality a non super human would need to pull with both hands to get it to move so fast..

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I just did a little testing and noticed something that seems off. Fly straight and level at around mach 1, and enable the info bar. Pull back hard on the stick. Your attitude will not change meaningfully for the first second or so, but you will be pulling 10-15-20G. That doesnt seem right to me. It may be right that the tomcat takes a little while to start pitching up, but I cant see how you can pull 20g and maintain basically the same attitude.

 

Might explain why some people snap their wings when they try to judge g load by look at how fast their attitude changes.

 

edit: trying it again, it pitches up instantly?


Edited by Vertigo72
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I wanted to, running OBS to record, but now I cant replicate it. Now when I pull it behaves as youd expect. Ive heard others say that they suffered severe input lag, I think specifically with FFB sticks, and that might have been what I noticed. And even weirder was I did get that high G readings, just the cockpit barely budged at all.

 

But there still is some delay. Sometimes. Just repeatedly pulling full back on the stick instantly, sometimes DCS input seems to be slowed somewhat. Same with centering. Not as dramatic as earlier, but its almost as if they implemented the "force simulation".

 

I cant show it on video because the delay is between my joystick moving and the stick in the game (as well as in the control overlay). So it would just appear as If pulling slower and centering slower than I really am. Can maybe someone with a non FFB try this? Just hit instant action / free flight. I dropped my ordenance not sure it matters, and keep yanking that stick as quick as you can (set invulnerability to on) at various speeds and check with the control overlay if there is a "smoothing"/delay or not

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...if anyone knows how to simulate this system in the B let me know...

 

Play around Saturation Y in Pitch Axis Tune - maybe 20 would be safe setting. You're welcome :)

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Not Tomcat exclusive, but for DCS in general.

 

Maybe if we make something like audio-visual cues for g's? Like we now have rattle and shake for flutter in the F-14, but different. Say, at 5+ g you start hearing experiencing screen edge graying out, and 7+ loss of color intensifies plus heart beat sounds, 8.5-9+ complete loss of color and tunnel vision onset and so on?

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High Gs apparently causes an immediate reduction of your hearing, so that could be easy to implement, just fade out sounds (and maybe fade in hard breathing or heart beat for extra coolness).

 

But I think the gradual G blackout we have is both realistic and helpful, its not hard to maintain ~9G in a turn. Its hard to judge when you begin your pull.

 

Whats also missing IMO, particularly for "keyboard pilots" who are rough with their stick is some feedback when you briefly pull (very) high Gs. There is no instant "penalty" like blacking out or any sort of warning or feedback, you obviously dont feel it even though you may have pulled 20G and you have degraded your airframe and then you may just snap your wings at a sustained 9G turn and wonder why. Maybe having instant onset of blackout/tunnel vision when exceed 8-9G would make pilots more aware of the high G load when jerking the stick, or when beginning their pull


Edited by Vertigo72
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I'm fine with current implementation. We already have shaking, heavy breathing, tunnel vision and color loss, rattle sounds, metal bending sounds - that's more than enough to warn you. If one doesn't even know he's speeding and yanks the stick - there's nothing that can save him.

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If you have the means, buttkicker/simshaker is a really immersive thing to have. We worked closely with their devs to implement it properly.

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