Skid on shore landing

[draconus]

8 hours ago, Clunk1001 said:

Following a normal landing, traveling under 50kt, aircraft do not perform a full 180 spin with minimum rudder input. 

Neither does the Tomcat unless you do crazy stuff no sane pilot would do IRL.

Not one track was posted here but it's usually speeding with parking brake on.

[Clunk1001]

1 hour ago, draconus said:

Neither does the Tomcat unless you do crazy stuff no sane pilot would do IRL.

It does for me.   It does for the OP.   It clearly does for other people.

No, I am not speeding down the runway and pulling the parking break...but that is indeed the exact effect I am experiencing.

 Your assumption that a reported issue with DCS cannot possibly be a real issue because you haven't seen it, suggests that maybe you've worked in IT Support too long  

My intention here is just to explore the reported issue, share my experience, and possibly find some explanation, and maybe a solution or work-around, for the OP, and myself, and others. 

I know I am not doing anything wrong as far as pilot input/aircraft operation goes....I know aircraft operated under normal conditions do not behave this way.  And - no offence intended - unless you personally have real-world experience (outside that of PC based flight simulators) your views of real-world aircraft handling and operation on a 'realistic handling'  issue, would largely come from a position of ignorance (happy to stand corrected on your background).  I only say this as your intention on here seems to be to blindly refute any possible suggestion that DCS might be "unrealistic", and you adhere to the absolute position that everyone else must be doing it wrong.   

Anyway, to continue, (productively), I may have an axis mapping issue (e.g. brakes are ON or OFF, applying 0 or 100%, no in-between) which is exasperating a possible 'friction' issue previously mentioned. 

I'll post a video/track...

[Clunk1001]

8 hours ago, RustBelt said:

This is a sim engine problem with tire to ground contact. It is very strong in the Tomcat. Any reverted rubber hydroplaning is a one way variable until a full stop. It behaves better with Spoiler/Antiskid - BOTH and turning the NWS on under 100 Kts. 
 

The workaround is to try real hard to be careful on the brakes until you come to a stop. The sim can’t reestablish traction on the move very well.
 

Ground Dynamics are always a distant tertiary in flight sims. You should have seen what a mess it was when the Carriers were new and the sim couldn’t comprehend a “ground” that moved.

Thanks RustBelt, this makes a lot of sense,  and would go some way to explaining why even the briefest application of braking (100% full brakes due to key/axis mapping) would start an irrecoverable loss of traction. 

[ShuRugal]

19 hours ago, RustBelt said:

Ground Dynamics are always a distant tertiary in flight sims. You should have seen what a mess it was when the Carriers were new and the sim couldn’t comprehend a “ground” that moved.

that was super fun.  aircraft walking sideways off the deck.

[Dragon1-1]

13 hours ago, Clunk1001 said:

I know I am not doing anything wrong as far as pilot input/aircraft operation goes...

Do you? In that case, care to tell us if the status of your NWS light when the jet spins out? We should distinguish minimal rudder input from minimal NWS input. The former won't do much at all at 50kts, rudder in the Tomcat becomes effective at around 80-100kts. The latter, though, will send you spinning if you use it at speed. NWS in the Tomcat has a far higher angle than land-based planes, such as anything you might have flown in your career. It's meant for tight turns on the carrier, unlike the Hornet, the Tomcat doesn't have any way to toggle the angle, as such, its NWS is extremely touchy. IRL, you'd track down the runway first with rudder, then differential braking, and use NWS only when at taxi speed. If you don't have differential braking, your best bet is to point the jet the right way while the rudder still works. It really doesn't need much runway to slow down.

100% brake will definitely make it worse, too. Just like you shouldn't brake heavily when taking a turn in a car. The anti-skid system in those old jets isn't perfect, and slamming the brake to 100% is a good way to spin out (and unlike in a car, you've only got brakes in the rear). The particulars of DCS ground friction and suspension mechanics are a bit suspect, but here, I suspect the problem is that you're turning the nosewheel far more than you think you are.

[RustBelt]

14 hours ago, Clunk1001 said:

Thanks RustBelt, this makes a lot of sense,  and would go some way to explaining why even the briefest application of braking (100% full brakes due to key/axis mapping) would start an irrecoverable loss of traction. 

Yea I curved the hell out of my brake axis so it doesn’t get anywhere near even 80% until it’s almost full travel.

Gotta switch to load cells some day. I had hoped a kit would be out by now but, nope…

[Clunk1001]

8 hours ago, Dragon1-1 said:

Do you? In that case, care to tell us if the status of your NWS light when the jet spins out? We should distinguish minimal rudder input from minimal NWS input. The former won't do much at all at 50kts, rudder in the Tomcat becomes effective at around 80-100kts. The latter, though, will send you spinning if you use it at speed. NWS in the Tomcat has a far higher angle than land-based planes, such as anything you might have flown in your career. It's meant for tight turns on the carrier, unlike the Hornet, the Tomcat doesn't have any way to toggle the angle, as such, its NWS is extremely touchy. IRL, you'd track down the runway first with rudder, then differential braking, and use NWS only when at taxi speed. If you don't have differential braking, your best bet is to point the jet the right way while the rudder still works. It really doesn't need much runway to slow down.

100% brake will definitely make it worse, too. Just like you shouldn't brake heavily when taking a turn in a car. The anti-skid system in those old jets isn't perfect, and slamming the brake to 100% is a good way to spin out (and unlike in a car, you've only got brakes in the rear). The particulars of DCS ground friction and suspension mechanics are a bit suspect, but here, I suspect the problem is that you're turning the nosewheel far more than you think you are.

As mentioned in my first post, NWS is OFF. I genuinely do have a very good understand of the forces acting on an aircraft on the landing roll. I have done it irl thousands of times.  And I understand aircraft configuration requirements. And aircraft control inputs and the effects.

For example, use of Aileron during ground roll was mentioned….yes, fine…but aileron on ground roll is used for crosswind control, not steering.  But as the effects of crosswind on groundroll are not simulated in dcs it negates the need for aileron during ground roll which is a factor in real life operations (different discussion for a different day).  Unless you have flown irl (to at least perhaps ppl or cpl level), you may not know about aileron use on ground roll at all, as pc games won’t simulate the effect.
My point being, I know I’m not ending up on the grass here as a result of incorrect operation (brake axis mapping aside).

My rudder axis input in the f14 is extremely curved, so the rudder input I’m carefully applying on the ground roll is perhaps 3%.  That is not enough no make a noticeable difference when flying (except when tanking),  it’s barely enough to keep centerline on ground roll.  But it is enough to induce a 180 degree spin at below 50kts in the tomcat.

Though it doesn’t need rudder input to spin on the runway, I believe this can be caused by a momentary brake application (100% brake due to key binding, below 50kts) with an asymmetric weapon loadout.  But that is definitely going to need a video to prove.  
 

The first time it happened in the f14 (as I usually land on a carrier), I assumed it was a tyre blow-out, as I’d diverted to a land base due to damage.  And I thought it was really cool that DCS/Heatblur simulated tyre damage (it was exactly like the video draco posted earlier)…..then it happened again, and again, and again.

i usually land on carriers in dcs, so usually not an issue.

Anyway, ill get a video uploaded at the weekend…

Edited May 30 by Clunk1001

[draconus]

2 hours ago, Clunk1001 said:

Anyway, ill get a video uploaded

It's of little or no use for debugging. Save a track.

Both aileron on ground and tyre damage are simulated in DCS. But lateral stick movement was only advised by IronMike for fast rolls on runway, not because of crosswind, but rather lateral stick also moves stabilators in a differential way which causes yaw forces, just like rudders, at speed.

[Clunk1001]

1 hour ago, draconus said:

It's of little or no use for debugging. Save a track.

Both aileron on ground and tyre damage are simulated in DCS. But lateral stick movement was only advised by IronMike for fast rolls on runway, not because of crosswind, but rather lateral stick also moves stabilators in a differential way which causes yaw forces, just like rudders, at speed.

Thanks for the info. I'll upload a track too.   The advantage of the video is that I can put music to it which will significantly enhance the ice-skating style runway pirouettes.  I was thinking Strauss.