Tuned Ground Handling

[frumpy]

Hi guys,

 

 

inspired by this video (

) I played a bit with the parameters of FMOptions.lua . Now the required amount of thrust for getting it to move is about 950 RPM and the brakes are a bit less effective. So if you taxi often but don't do a runup, this may be for you.

 

 

 

If you want to try it, then place the file into \DCS World\Mods\aircraft\TF-51D\FM and do a backup of the old file.

 

 

I'd like to smoothen out the rudder effectiveness on ground, in order not to overcontrol the Mustang. Does anyone know how this is done? Is there a developer manual describing the parameters?

I am also not too happy with the brakes, while they seem to be more realistic in braking (no more nose-overs), they are unable to hold during the runup at 2300 RPM. Hm.

FMOptions.lua

Edited January 17, 2020 by frumpy

[Magic Zach]

Ah yes, I've seen this video. Great job!

I think you should contact Nineline or BIGNEWY, to maybe get this mod integrated.

[Art-J]

^ I sure hope they will NOT. I'll take possibility of performing realistic runups and mag checks @ 2300 RPM over a less important initial rolling friction issue.

 

Fiddling with tyre friction values opens a can of worms - can improve some things while messing up others at the same time, as we've seen with revision of 109 ground physics back in '18.

[Magic Zach]

^ I sure hope they will NOT. I'll take possibility of performing realistic runups and mag checks @ 2300 RPM over a less important initial rolling friction issue.

 

Fiddling with tyre friction values opens a can of worms - can improve some things while messing up others at the same time, as we've seen with revision of 109 ground physics back in '18.

In the .lua, there are only three variables for tire friction for each of the Mustang's wheels. Don't work yourself up. To deny a small and rather competitively effortless step is going 300% overboard

[frumpy]

Art-J, you are right on this, my initial joy is a bit dampened. For now I see it as a workaround to make taxiing more realistic if you can abdicate the runup. I'll see if I can find more information on how to tune the parameters.

[Ala13_ManOWar]

Youtube vídeos always make good sources for a FM change out of your guts' feelings, right? What could possibly go wrong?

 

 

 

S!

[Magic Zach]

Youtube vídeos always make good sources for a FM change out of your guts' feelings, right? What could possibly go wrong?

 

 

 

S!

Clearly you didn't watch the video

[grafspee]

Clearly you didn't watch the video

 

Agree :)

[Ala13_ManOWar]

Clearly you didn't watch the video

I watched the video time ago. Still I believe you can't tell things out of your guts just watching a video.

 

 

S!

[grafspee]

I watched the video time ago. Still I believe you can't tell things out of your guts just watching a video.

 

 

S!

We don't tell anything, person who made this video compared dcs p-51 to real tf-51 and he said that tf-51 would start rolling even at rpm lower then 900 rpm.

And you still haven't watched this one :)

Edited January 20, 2020 by grafspee

[Ala13_ManOWar]

We don't tell anything, person who made this video compared dcs p-51 to real tf-51 and he said that tf-51 would start rolling even at rpm lower then 900 rpm.

Yeah, of course. And how you compare that to the exactly very same conditions in the sim? How can you even tell the conditions are exactly the same? How can you even tell the aircraft are the exact very same, same weight, same conditions, same everything? You can't, and every single one of those details do affect DCS (not so other so called "sims"). So now, from hearing what others say, which could be flawed in the first place ahem, you can tell how much DCS must be finetuned "by ear". Right, so sensible method.

 

 

 

S!

[grafspee]

Yeah, of course. And how you compare that to the exactly very same conditions in the sim? How can you even tell the conditions are exactly the same? How can you even tell the aircraft are the exact very same, same weight, same conditions, same everything? You can't, and every single one of those details do affect DCS (not so other so called "sims"). So now, from hearing what others say, which could be flawed in the first place ahem, you can tell how much DCS must be finetuned "by ear". Right, so sensible method.

 

 

 

S!

 

If you actually watched this, you would not ask those question because he explained everything there. weight was the same and conditions were very close

[Art-J]

In either case, being curious, just tried TF-51 with 5 (five) % fuel, Kobuleti, summer weather. Still needed about 1150-1200 RPM to start rolling.

 

D with full fuel, bombs and rockets required about 1300.

Edited January 20, 2020 by Art-J

[Ala13_ManOWar]

If you actually watched this, you would not ask those question because he explained everything there. weight was the same and conditions were very close

I did, and no, he did what he could which is way different from really telling that's the exact and perfectly good test.

 

 

S!

[Ala13_ManOWar]

In either case, being curious, just tried TF-51 with 5 (five) % fuel, Kobuleti, summer weather. Still needed about 1150-1200 RPM to start rolling.

 

D with full fuel, bombs and rockets required about 1300.

Did you try winter ones? In cold temps and high atmospheric pressure the engine is way more powerful than summer at ground level.

 

 

S!

[Quadg]

In either case, being curious, just tried TF-51 with 5 (five) % fuel, Kobuleti, summer weather. Still needed about 1150-1200 RPM to start rolling.

 

D with full fuel, bombs and rockets required about 1300.

 

if only you could remove the guns that weigh the same as 3 average people.

 

you would probably taxi at 950rpm :)

[frumpy]

Did you use the file with the P-51D? I don't use that module, just tried it with the TF-51. I am no sure which difference bombs will make. A fully loaded 747 will not move at idle power, while being light it may accelerate without having the parking brake on.

[grafspee]

if only you could remove the guns that weigh the same as 3 average people.

 

you would probably taxi at 950rpm :)

 

you can just drain wing tanks to almost nothing in war time p-51 and you will have similar weight.

[grafspee]

Did you try winter ones? In cold temps and high atmospheric pressure the engine is way more powerful than summer at ground level.

 

 

S!

 

Engine at taxing power settings will not have big difference winter/summer, it would be logical in difrence 1100 or 1200 not 700 and 1200 rpm.

Btw P-51 in dcs will start rolling at 1000 rpm but it take couple minutes to unglue it self from earth. It will creep froward at this rpm and after couple minutes it will start rolling

Edited January 21, 2020 by grafspee

[Yo-Yo]

We don't tell anything, person who made this video compared dcs p-51 to real tf-51 and he said that tf-51 would start rolling even at rpm lower then 900 rpm.

And you still haven't watched this one :)

 

Depends on mass and surface conditions. Compare tarmac, smooth concrete and large grain old concrete... Initial friction will be way different. So, it's not a aircraft physics issue but more the surface issue.

[zcrazyx]

Could be something to do with the brakes as well? A super cub I got my tailwheel endorsement on had to have brakes replaced twice due to taxiing and take off with the parking brake on lol.

 

Brake binding would be interesting.

[grafspee]

Depends on mass and surface conditions. Compare tarmac, smooth concrete and large grain old concrete... Initial friction will be way different. So, it's not a aircraft physics issue but more the surface issue.

 

Maybe, for example spitfire starts rolling much easier below 1000 rpm.

In p-51 if you set 1000 rpm and start to swing rudder left/right p-51 unsticking process takes much less time

Anyway this taxing problem don't concern me. Missing v-1650-9 in dcs this is my main concern :)

Edited January 22, 2020 by grafspee

[frumpy]

Depends on mass and surface conditions. Compare tarmac, smooth concrete and large grain old concrete... Initial friction will be way different. So, it's not a aircraft physics issue but more the surface issue.

 

 

I have no numbers on initial friction, but my gutfeeling (after pushing a few C172s around) tells me that the effect of an increase of 100 RPM (~~20% more thrust) will be larger than the effect of initial friction asphalt vs. grain concrete.

Things would be easier if there was a documentation on the FMOptions.lua. :)

[frumpy]

In p-51 if you set 1000 rpm and start to swing rudder left/right p-51 unsticking process takes much less time

 

 

I tried to set the wheelbrakes, increase the throttle and lift the tail with the elevator down. Works quite well, but the other way around (lifting the elevator to set the tail on the ground) does not seem to work. So the propstream affects the tail surfaces left, right and up, but not down?

[grafspee]

I tried to set the wheelbrakes, increase the throttle and lift the tail with the elevator down. Works quite well, but the other way around (lifting the elevator to set the tail on the ground) does not seem to work. So the propstream affects the tail surfaces left, right and up, but not down?

 

It works, but elevator will help a little to keep tail on the ground, but in case when tail is lifted CG is moved forward making it even harder to counter react. Prop thrust will win easy with elevator.

Once elevator(tail) is higher then nose tip it is very little what you can do to prevent nose tipping.

BTW yo-yo can we get feature so we can ask ground crew to strap our tail to the ground so we can do full power run-up ?

Edited January 22, 2020 by grafspee