Asphalt grip vs off road/grass grip simulation

[MaverickF22]

Hi there,

 

I want to discuss a little about an aspect which is intriguing me for some while, about the way the aircraft's tire grip/friction force is simulated for both concrete/asphalt/road and off road/grass conditions.

 

Now i know that the aircrafts like A-10 and SU-25 are creating a huge amount of normal force over a given contact area between the tire and the ground, with it's corresponding distribution (main gear and nose/tail wheel), which creates a given pressure, which might be quite high for the aircrafts in question, if we'd want to relate them to a heavy truck or something else..., but even so, the difference seems quite too high. I'm not putting my hand into the fire saying that the main gear wheels of a more or less loaded A-10 wouldn't sink a bit into the off road terrain, but how much would that happen to be as to have it completely stuck even with full throttle? The same thing can be seen with an F-15 which has a full afterburner thrust of 1.5 times it's own weight, yet still it's so stuck on an off road terrain like it would be completely buried.

 

The Su-25's nose gear's grip on asphalt is almost as double as for snow:P, but not for asphalt..., and after that it also blows up for whatever reason or from an exaggerated high friction effect at high speeds, when cornering too much. So, some things seem exaggerated to either sides: grip is too low on asphalt, but tire blows up easily. And as for off road or grass, the Su-25's tires seem to love it, it's like driving on rails for the grip that it's given.

 

Also, the P-51 seems to be able to do some nice drifts on asphalt with those tires, but on a dirt/off road/grass terrain it has the same grip as Su-25 and A-10 (on rails), which is absurd once more.

 

Now these conditions exactly as they are now, are most probable for a rainy day..., if not perfectly simulated for that, where the asphalt/tarmac and concrete provide a less grip then for a normal day, while the earth/off road terrain or grass might get very muddy and increase the so called "grip" to almost 100%, but only if the tire would actually dig in..., otherwise it should be more slippery than for a wet asphalt.

 

I'm not saying anything out of everyone's knowledge, but..., i think it's time to try and modify these grip parameters for every situation, because the way it looks now isn't pretty realistic;), and we want realism, aren't we?

 

 

To give you an example, that planes should normally (in a sunny day with rock hard terrain) be able to operate/travel on an off road (i don't mean bumpy;)) terrain without so much sinking/digging effect (except for a wet day of course), i'll remind some of you guys, an example with a Boeing 737 from TACA Airlines which was forced to land on a patch of grass after loosing both engines, and that plane had a higher tire pressure on the ground than a loaded A-10C..., yet still (even if it started "digging in" a bit) it was able to takeoff from the same grass it landed on.

 

Watch from minute 31, unless you don't need the whole story:

http://www.youtube.com/watch?v=jnX1u5vp1J4

 

Let's make some changes..., only if time allows it of course;)!

 

 

Have a good day,

Cheers.

Edited June 22, 2013 by MaverickF22

[Weta43]

I'm not putting my hand into the fire saying that the main gear wheels of a more or less loaded A-10 wouldn't sink a bit into the off road terrain,

from 2 minutes 15 in... half the plane missing, no fuel, no weapons, and it sinks into the dirt like a plough - which I guess would make breaking out difficult, and make the plane track pretty well :)

 

Max takeoff weight for an Su-25 is 17,600kg ~ 6 metric ton per (narrow) wheel if evenly loaded - say 7 per main gear and 4 for the nose wheel ?

Bit more than your average truck

 

LnGXerN0tlo

Edited June 22, 2013 by Weta43

[Jeesus]

So not I'm the only one who's into this problem, at least it would be nice to have a quick response towing team at the airfield to get you back on track (directive radio call for ground crew is good for me :D ).

 

The worst thing in the world when you manage to get back to the home plate with your "Air Defence Generated Pile of Junk" and you weer of the runway a little bit as a result of the emergency situation and you know that no point in asking for repair because you have to restart/rejoin anyway. Just kills the fun.

 

Unfortunately it's far away from the bug fixing toplist :)

[OzStriker]

Well IRL it'd be tea and biccies with the boss so a restart/rejoin seems fair to me.

[Jeesus]

Well IRL it'd be tea and biccies with the boss so a restart/rejoin seems fair to me.

 

That completely makes sense :lol:

[Buzpilot]

Some planes are made to be able to use grass runways.

(Watch from 39sec)

 

 

And Su-25 are too, if not A-10 too.

[Mnemonic]

And for sure P-51

[MaverickF22]

Some planes are made to be able to use grass runways.

 

And Su-25 are too, if not A-10 too.

 

Thanks Buzpilot and good job with the video link! Nice review of the Jaguar!:D

 

Let's hope they'll do some changes for this manner in the future;)!

 

 

Cheers.

Edited June 23, 2013 by MaverickF22

[MaverickF22]

 

Max takeoff weight for an Su-25 is 17,600kg ~ 6 metric ton per (narrow) wheel if evenly loaded - say 7 per main gear and 4 for the nose wheel ?

Bit more than your average truck

 

 

 

Thank you very much for the video example ED Tester;), but as you can see, the ground was soften enough by the atmospheric conditions (humidity) and i'd say that it's pretty good for how much it sunk and didn't go further, as that Lightning would weigh about 3-4 tons at least in those given conditions.

 

Our ground attack aircrafts like A-10A/C and Su-25's weigh a lot more..., especially in a fully loaded condition, as you've mentioned, but in the sim, the A-10 especially, seems to fully sink it's wheels into a tough/dry ground so much (would require a monstrous amount of contact pressure for that) that there isn't any possibility of using the engine's thrust as an option to get out.

 

You could let these sinking/ground friction values as they are for a wet condition, they might be just right..., but for a dry ground they can't be this way!;) So i'd suggest having to sinking models for each plane, one for dry conditions and one for wet! This would again increase the realism we're looking for!

 

Also about the grip..., now all the planes seem to have a lot much higher grip and friction coefficients for soil/grass terrain than for usual asphalt/concrete terrains, and this is manly due to the fact that the game might simulate the sinking effect of the wheels into the ground, so this thing happens to P-51 as well (even if it is the lightest of all), making the P-51 run like on rail tracks over grass/soil terrains with no skidding at all, which requires a careful (small error margin) usage of the rudder while rolling (unless you like fireworks), yet on asphalt you can do some nice drifts and have only a 50% chance to fall on a wing.

 

 

Thank you for your reply!;)

 

Cheers.

[MaverickF22]

And for a little bit of entertainment:

 

 

http://www.youtube.com/watch?v=i_RhmgsJWH4

The Mig-21's weight was appreciably of at least 7 tons