DSR, CSR cars, Stohr, etc....

[IanGrohse]

http://dsr.racer.net/

This is an interesting thing to watch these days, as the level of quality, speed and inovative technology.....

For instance, take a look at this past years hot car.....the Stohr.....which is not only beutiful, but fast, reliable, and impressive in terms of technology....

http://www.stohr.com/page2.html

Steel space frame/carbon fiber chassis, paddle shifting, lots of amazingly beutiful crafted aluminum pieces(such as the rear suspension mounting), Aerodynamicly it uses the front and rear diffusers, etc.

I think its pretty interesting and exciting.

[choked_wasp]

A friend of mine has one of the Stohr's. It is a very well done car. However if you backed into a wall with one it would be VERY expensive.

I still want one though.

[Lee Janotta]

Have you seen their Formula Ford? Looked very fast right out of the box at Mid-Ohio this year, this could be a series contender in coming seasons.

I must applaud them, a very impressive record already for this company!

[Lee Janotta]

Have you seen their Formula Ford? Looked very fast right out of the box at Mid-Ohio this year, this could be a series contender in coming seasons.

I must applaud them, a very impressive record already for this company!

[David Ferguson]

My wife owns Stohr #4, and we've been doing a lot of the aerodynamic development on the car. Our next test will involve testing three different wing profiles, and trying different wing locations (ie. high vs low wing configurations) trying to make the low-pressure area under the wing pump the diffuser some more.

I am open to ideas and input from anyone that had looked at the Stohr or has suggestions for aerodynamic improvements (it's very low drag now due to small frontal area, but could use more downforce -- can't we all?)

You may post here, or email me privately at ferg@veracitydata.com

[Lee Janotta]

Always nice to have another real racer on the forum.

Hmm... Have you considered tying the rear wing endplates to the bodywork? It seems to work for Audi, Riley & Scott, and to a lesser but more relevant degree, the Beasleys.

For the front end... Well, I don't have any windtunnel reasearch to back this up, but what about a wing similar to the Picchio, running form that raised nose out to the leading edge of the fenders in a curve. It's got to be a high-pressure area, so the downforce created could be sigificant.

A more conventional solution would be to simply stick on a front wing just below driver's line-of-sight, similar to what some of the IMSA teams (especially 962s) ran on street circuits "back in the day".

I've no idea how feasible it is, but cutting down on the front rolling stock and lowering those fenders would probably add quite a bit of top end.

Just the thoughts of someone who got a D in his high school physics class, so take them for what they're worth.

[IanGrohse]

But what kind of downforce are you looking for? Front, rear, overall?

Sounds like you are looking for rear downforce......I was going to say was Lee said, about the wing endplates....Move the wing mounting supports inboard....Then make full endplates going to the rear fenders.....
Also perhaps move the wing rearward a few inches...

And add more elements to the wing....

Also, this...
http://www.mulsannescorner.com/bentleylmgtp3.htm

[RacingManiac]

That Stohr's front suspension looks odd.....pushrod actuated with the coilover mounted ON the pushrod?! or is it something else...
http://www.stohr.com/fronttop.jpg

and none of these uses any anti-roll.....is it not allowed in the reg?

[David Ferguson]

Thanks for the comments.

At the moment, we are looking for overall downforce, so far it has been easier to add rear downforce (just turn up the wing angle, and/or add a larger wicker to the wing and the trailing edge of the bodywork).

The front took a bit more work, blocking off some flow that was going inside the sidepods (thus "trapping" the air on top of the splitter under the raised floor) was a helpful change. We will be extending that floor, and possibily adding some strakes to the diffuser in the nose (it has none right now).

Back to the rear change for our upcoming tests. The wing mounts just happen to line up with the outside edges of the diffuser, so I was going to extend them to the rear and downward, almost to the ground -- I hope this will be even better than extended the wing endplates downward (but I'll try that as well). The wing would then mount about 6 or 8 inches rearward of where it is now -- the mount would extend the full cord of the wing. If these tests gain rear downforce, we'll definitely switch our focus back to the front.

The front suspension mechanics of the Stohr has been used on a few other sports racers (I believe Lola may have tried this), the geometry works out to give the shock a 1:1 motion ratio, something you don't normally get with outboard shocks.

Lee Stohr does not really like anti-roll bars, and while he designed them and delivered the parts eventually, the car that won the Runoffs had none. Balance changes are made with springs or roll-center height. The car has been wonderfully balanced so far, making the need for adjustable anti-roll-bars a moot point.

[IanGrohse]

Originally posted by RacingManiac
That Stohr's front suspension looks odd.....pushrod actuated with the coilover mounted ON the pushrod?! or is it something else...
http://www.stohr.com/fronttop.jpg

and none of these uses any anti-roll.....is it not allowed in the reg?

This is Lee Stohr's reasoning for that front suspension:

"The new Stohr DSR will have an out-board, pushrod and bellcrank front suspension. With this layout it is not hard to get good shock travel. One inch of shock travel per inch of wheel travel is easy to achieve. Also, the driver compartment is larger around the legs because the springs and shocks aren't there. And the body can perhaps be lower because the springs are not mounted above the drivers knees. The springs aren't mounted under the frame because of aerodynamic reasons. "

[RacingManiac]

interesting I suppose....since they do have the enclosed body work to work with...

[danhx]

[QUOTE]Originally posted by Lee Janotta
For the front end... Well, I don't have any windtunnel reasearch to back this up, but what about a wing similar to the Picchio, running form that raised nose out to the leading edge of the fenders in a curve. It's got to be a high-pressure area, so the downforce created could be sigificant.

A more conventional solution would be to simply stick on a front wing just below driver's line-of-sight, similar to what some of the IMSA teams (especially 962s) ran on street circuits "back in the day".

I've no idea how feasible it is, but cutting down on the front rolling stock and lowering those fenders would probably add quite a bit of top end.[END QUOTE]

It seems like sticking a "Picchio wing" on the front of car that wasn't designed with that already in mind would add a pretty substantial amount of drag. Since the Stohr has a "nose", unlike the Picchio, it looks adding on a wing would blunt the front of the car and drop the lift-to-drag ratio...That's just the opinion of a communication major, so take it with a grain if salt...