RC EVOLUTION - 遙控工房 - 香港RC遙控車討論區

標題: Why 1/12 use negative caster gain? [打印本頁]

作者: dxmaxian 時間: 2011-7-29 10:01
標題: Why 1/12 use negative caster gain?
Is anyone know why 1/12 use negative caster gain?

作者: macau-rc 時間: 2011-7-29 11:18
本帖最後由 macau-rc 於 2011-7-29 11:18 編輯

Coz car need more steering in off power, this calling reactive caster.

作者: nel3838 時間: 2011-7-29 12:35

macau-rc 發表於 2011-7-29 11:18

登錄/註冊後可看大圖

Coz car need more steering in off power, this calling reactive caster.

how does this theory work? Thx Ching.

作者: nb576uk2004 時間: 2011-7-29 23:34
reduces caster at turn in and increases it at exit

作者: nel3838 時間: 2011-7-30 10:27

nb576uk2004 發表於 2011-7-29 23:34

登錄/註冊後可看大圖

reduces caster at turn in and increases it at exit

I see thx. Thou would that make turn in sharper and exit more push (under steer)? And if so isn't that the opposite needed. Sorry, I am not experienced with 1/12

作者: nb576uk2004 時間: 2011-7-30 13:13
As you turn the wheels during cornering the angle of the caster affects the angle of the camber. The more caster you run the more the outside wheels camber will be increased negatively as the wheels turn. Since this camber increases the more you turn the wheels, called dynamic caster instead of static caster.

作者: dxmaxian 時間: 2011-8-1 11:39
I still confused about reactive caster.
Why need reduce caster when off throttle.
It seem when you go straight, The car had over camber, Then you turn in corner compress front spring, The total camber back to actually car needed
In this, open throttle will fiel "push out", off throttle will turn-in more, That is correct feel.
But camber gain is against about this.
Why need fighting system?

in turn
reactive caster                   camber gain
normal--------------------------------------------------------
over camber                   under camber
compress spring-------------------------------------------
reduce camber                increase camber

作者: vin00002002 時間: 2011-8-2 01:23
like

作者: nb576uk2004 時間: 2011-8-3 21:04
本帖最後由 nb576uk2004 於 2011-8-3 21:05 編輯

let say, 2 caster 2 -ve camber,0 reactive caster, when cornering, outside wheel will change to 3-4 -ve camber, result in reducing the contact patch area traction
Using a reactive caster can reduce the excess camber and control the contact patch size .

作者: nel3838 時間: 2011-8-4 23:22

nb576uk2004 發表於 2011-7-30 13:13

登錄/註冊後可看大圖

As you turn the wheels during cornering the angle of the caster affects the angle of the camber. The ...

I think I get it now.  Pls see if below understanding is correct!  Thx.

If without reactive caster, at turn in, total "effective" camber (caster + static camber) may be too great, and the car could turn in too sharp (may cause over steering and tail out).

With reactive caster, caster is reduced at turn in and thus "effective" camber is reduced, making smoother turn in; and then at corner exit, caster increases thus "effective" camber also increases, giving more on power steering and therefore tighter corner exit.

作者: nel3838 時間: 2011-8-4 23:28

nel3838 發表於 2011-8-4 23:22

登錄/註冊後可看大圖

I think I get it now. Pls see if below understanding is correct! Thx.

If without reactive c ...

Or put another way, reactive caster reduces "over cambering" of static caster at point of turn in, making the car has smoother turn in; which in theory should also be useful for power wide sweep turns so the car don't dig turns so easily.

作者: Dkwc79 時間: 2011-9-5 14:25
seemed difficult to understand.. but can try the effect with + - camber setting.

作者: tiger1 時間: 2011-9-5 17:19
it is almost like rocket science...

歡迎光臨 RC EVOLUTION - 遙控工房 - 香港RC遙控車討論區 (https://www.rc-evo.com/xbbs/)