Active aero on a car

Breaking news, useful data or technical highlights or vehicles that are not meant to race. You can post commercial vehicle news or developments here.
Please post topics on racing variants in "other racing categories".
User avatar
godlameroso
513
Joined: Sat Jan 16, 2010 8:27 pm
Location: Miami FL

Active aero on a car

Post



Notice like an F1 car's front wing, the rear wing on this car lowers on the side that rolls aiding yaw.
Saishū kōnā

User avatar
Andres125sx
362
Joined: Tue Aug 13, 2013 9:15 am
Location: Madrid, Spain

Re: Active aero on a car

Post

Looks like a broken wing

Tommy Cookers
Tommy Cookers
582
Joined: Fri Feb 17, 2012 3:55 pm

Re: Active aero on a car

Post

godlameroso wrote:
Thu Jun 17, 2021 1:27 am

Notice like an F1 car's front wing, the rear wing on this car lowers on the side that rolls aiding yaw.
how is the video car (rear) wing emulating an F1 car front wing ? doesn't ....

a banked front wing give a favourable side force component and this gives a favourable yaw moment ... but ....
a banked rear wing give favourable side force component and this gives an unfavourable yaw moment

and btw
here in your description the car rolls on one side (by implication not on the other side ?)
in another thread your description mentions front heave (by implication different from rear heave ?)
it seems clear to me that 'your' car has a broken chassis

User avatar
godlameroso
513
Joined: Sat Jan 16, 2010 8:27 pm
Location: Miami FL

Re: Active aero on a car

Post

My car? Broken chassis? How? I just replaced the rear subframe not too long ago, since it's directly mounted to the chassis with captive nuts welded on the chassis if the chassis were broken alignment of the subframe to the chassis would be impossible.

New subframe has better pick up points for the upper wishbone.

Heave is just another way to generate aero forces. If you pitch the nose down the front splitter gains downforce to a point. It's like pitching up on a plane. If you pitch up and roll your plane yaws like it was supposed to.

That's where left foot braking blended with acceleration come in to play. With soft dampers and stiff springs you have fast weight transfer. The trick is on the rebound damping to help the timing of the weight transfer.

Rebound damping at the rear and compression damping at the front both control front nose dive and rear roll all at once. Because rebound damping controls the timing of the rear inside wheel lifting under roll and/or heave.
Saishū kōnā

Tommy Cookers
Tommy Cookers
582
Joined: Fri Feb 17, 2012 3:55 pm

Re: Active aero on a car

Post

godlameroso wrote:
Thu Jun 17, 2021 11:30 am
My car? Broken chassis? How? ....

Heave is just another way to generate aero forces. If you pitch the nose down the front splitter gains downforce to a point. It's like pitching up on a plane. If you pitch up and roll your plane yaws like it was supposed to.

That's where left foot braking blended with acceleration come in to play. With soft dampers and stiff springs you have fast weight transfer. ....
handily for my purpose it's all been put into one post (the dangerously sloppy terminology)

this ....
Heave is vertical motion (along the Z axis)
(so front heave can't be different to rear heave unless the chassis is broken)

Heave isn't like pitching up
(heave and pitch are different things - that's why they are called by different names)
pitch is the angular motion (around the Y axis)

and ....
weight transfer is (in essence) unaffected by damper forces
the wheels 'see' the force from deceleration of the car's mass regardless of the route(s) taken by that force
(yes if the suspensions travel more eg due to low damper force there will be some further change in wheel loads)

'left foot braking blended with acceleration' - what does that mean ?? (rwd presumably ?
combined braking and tractive torques ..... producing .....
net torque zero ?
net torque decelerating ?
net torque accelerating ?


ok - the tilting DF wing might seem to be one of the designer's rare 'free lunches'

btw
I did sustained inverted flight on the basis that sustained inversion didn't throw out oil (reversion to erect flight does)
yes inverted turns could be seen as more efficient and easier

User avatar
godlameroso
513
Joined: Sat Jan 16, 2010 8:27 pm
Location: Miami FL

Re: Active aero on a car

Post

Heave happens on an axle equal heave on both axles is not what we want. We want to keep or slightly increase the rear ride height, but lower the front. That is pitch when considering the whole car.

Blending left foot braking with acceleration gives more precise platform control. You must develop your inner avionics. I learned how to left foot brake on the simulator. An ND MX5 is a great trainer for driving with weight transfer. I believe that car is in iracing. Probably why Norris and Verstappen are so adept at it :wink:

It's also on Assetto Corsa both cup and road ND. The road version is even more exaggerated with the way the car rolls just like in real life.
Saishū kōnā

Tommy Cookers
Tommy Cookers
582
Joined: Fri Feb 17, 2012 3:55 pm

Re: Active aero on a car

Post

godlameroso wrote:
Thu Jun 17, 2021 1:30 pm
Blending left foot braking with acceleration gives more precise platform control .....
An ND MX5 is a great trainer for driving with weight transfer.
what ?
combined braking and drive ie left foot braking was what the writer should have written

trail braking has a fixed brake balance - it's effective (by combining cornering and braking) but not ideal
skillful left foot braking modulates the driven axle torque to give in effect ideal brake balance in cornering

deceleration (whether produced by braking or in cornering brakes-off) is what produces so-called weight transfer
the forces on a trackday or similar car being essentially mechanical forces all acting at track level
and high cornering forces from the tyres can only come with high tyre forces trying to decelerate the car

the benefits from left foot modulation of brake balance are sometimes portrayed by analogy with weight transfer
but there is no weight transfer or 'platform control' - except when there is (longitudinal) acceleration or deceleration

left foot braking works without acceleration or deceleration - or with of course
(Schumacher's Benetton telemetry at Silverstone iirc showed it working without)
the benefits are getting more from the tyres .....
by ideally combining cornering and deceleration (and by ideally distributing the tyre task front and rear)

we all know that combined cornering and deceleration (and combined cornering and acceleration) are race winners

PhillipM
PhillipM
425
Joined: Mon May 16, 2011 2:18 pm
Location: Over the road from Boothy...

Re: Active aero on a car

Post

That example is of entirely how not to do active aero, it's a marketing gimmick to look good and gives less performance than a similar sized static wing would, both in terms of weight and cornering grip.

All show, no go.