Internal Body Aerodynamics

Okay, this is overly complicated, probably because of some rule that doesn’t allow control valves for aero devices. So the driver activates a fluid switch by blocking a pipe with his hand.

They stall the wing in such a way that even though lift drops, drag drops significantly. For use on straights, allows running high downforce wing.



[ame]https://www.youtube.com/watch?v=Ai3O03S55YI[/ame]
 
Interesting. The side pod diffuser tunnels that they show as banned early in the video are what I have on my '56 - between the outside of the frame rail and the inside of the side body skirt. I have the rear wing adjusters on a bellcrank assembly with the future possibility of adding an aircraft trim motor to control the wing AOA. It would take something faster acting than a trim motor to rapidly change the angle in order to create drag for decel, especially after trimming out the AOA for low drag on a straight and then going back to high downforce for a corner. I see the potential to get yourself in a lot of trouble. I guess with F-1 type money you can overcome these things.

Diffuser Tunnels.jpg
 
mfain, I think Phantomjock posted an active control system for wings. It was a year or two ago.

Sounds like the tunnels should work then.

Anxious to hear/see video of your car.
 
Pappy -

Like to hear more about your Lotus 78/79 inspired side tunnels. I have had side tunnels in the SR side pods for about 3 years now. Built as 10 degree and 20 degree. Haven't"swept" with an airfoil section - just straight, flat ceilings. Butt dyno says it works well. Plan has foam and glass inserts, not built yet.

I had side skirts (Chaparral-style) and that was like the car was literally on rails. They were 2 inch aluminum, and Tech missed seeing them as we teched on grass. Pulled them after a weekend to stay "legal."

Faster motor? Maybe a servo is the answer. Placement of the control arm is key to keeping the loads down. On my back burner is an Active Aero module to be semi-autonomous, sort of wings level trim, that "paddles off" under acceleration (DRS) and under braking - increases. I'm sure we have some brighter EEs here than me.

I have planned a complete testing of some of the components ion the SR. It has been the Mule for the "vette mods, and once I get a few bugs sorted out and the test done - I'll share too.

Cheers - Jim
 
Some nice visualization.

The best image is at 1:16, but you almost have to pause it.

[ame]https://www.youtube.com/watch?v=cGrFN2jZeY8[/ame]
 
phantomjock said:
Pappy -

Like to hear more about your Lotus 78/79 inspired side tunnels. I have had side tunnels in the SR side pods for about 3 years now. Built as 10 degree and 20 degree. Haven't"swept" with an airfoil section - just straight, flat ceilings. Butt dyno says it works well. Plan has foam and glass inserts, not built yet.

I had side skirts (Chaparral-style) and that was like the car was literally on rails. They were 2 inch aluminum, and Tech missed seeing them as we teched on grass. Pulled them after a weekend to stay "legal."

Faster motor? Maybe a servo is the answer. Placement of the control arm is key to keeping the loads down. On my back burner is an Active Aero module to be semi-autonomous, sort of wings level trim, that "paddles off" under acceleration (DRS) and under braking - increases. I'm sure we have some brighter EEs here than me.

I have planned a complete testing of some of the components ion the SR. It has been the Mule for the "vette mods, and once I get a few bugs sorted out and the test done - I'll share too.

Cheers - Jim
Click to expand...

Hey Jim,

I have the tunnels/belly pan/diffuser off the car right now doing some undercarriage work, but I was able to take a couple of photos to show how the diffuser tunnels are set up. The sketch shows how the tunnels blend into a rounded leading edge that is actually an extension of the firewall. The area highlighted at the rear is the portion of tunnel that is shown in the following photos. Photo 2 shows the side skirt (under construction at the time of the photo) and the third photo is of the tunnel assembly with side skirt. The last photo shows the actual diffuser tunnel from the back looking forward - inverted wing profile with a 12 degree diffuser discharge angle (including vehicle rake).

56 Corvette Tunnel 4_LI.jpg

56Corvette Side Skirt Under Construction_LI.jpg

Tunnel 2.jpg

Tunnel 3.jpg
 
Pappy the detail on your car never ceases to amaze me!

I’m interested to see what (if anything?) you’ve done to smooth airflow going under the rear suspension out the rear of the car
 
vette427sbc said:
Pappy the detail on your car never ceases to amaze me!

I’m interested to see what (if anything?) you’ve done to smooth airflow going under the rear suspension out the rear of the car
Click to expand...

Got a couple of tricks up my sleeve. I originally had a diffuser that ran from just behind the rear axle to the rear of the car. It wasn't very pure from a downforce perspective - too short and somewhat convoluted with provision for the exhaust tips. There are a couple of photos of that original diffuser in post 110, page 11 of this thread. After I changed rear suspension I modified that piece to stay in place, but I am now constructing a second diffuser that will run from just in front of the front of the differential to the rear of the car. It will be below and supported by the rear strakes on the original (upper) diffuser and there will be a 4 inch vertical gap between the two. Air from the area of the spinning axle shafts, from the trans and diff cooler fans, and the exhaust will pass between the diffusers. The bottom diffuser will be for pure aerodynamic function - adjustable diffuser divergence angle with long vertical strakes very similar to my Viper ACR.

Pappy
 
mfain said:
phantomjock said:
Pappy -

Like to hear more about your Lotus 78/79 inspired side tunnels. I have had side tunnels in the SR side pods for about 3 years now. Built as 10 degree and 20 degree. Haven't"swept" with an airfoil section - just straight, flat ceilings. Butt dyno says it works well. Plan has foam and glass inserts, not built yet.

I had side skirts (Chaparral-style) and that was like the car was literally on rails. They were 2 inch aluminum, and Tech missed seeing them as we teched on grass. Pulled them after a weekend to stay "legal."

Faster motor? Maybe a servo is the answer. Placement of the control arm is key to keeping the loads down. On my back burner is an Active Aero module to be semi-autonomous, sort of wings level trim, that "paddles off" under acceleration (DRS) and under braking - increases. I'm sure we have some brighter EEs here than me.

I have planned a complete testing of some of the components ion the SR. It has been the Mule for the "vette mods, and once I get a few bugs sorted out and the test done - I'll share too.

Cheers - Jim
Click to expand...

Hey Jim,

I have the tunnels/belly pan/diffuser off the car right now doing some undercarriage work, but I was able to take a couple of photos to show how the diffuser tunnels are set up. The sketch shows how the tunnels blend into a rounded leading edge that is actually an extension of the firewall. The area highlighted at the rear is the portion of tunnel that is shown in the following photos. Photo 2 shows the side skirt (under construction at the time of the photo) and the third photo is of the tunnel assembly with side skirt. The last photo shows the actual diffuser tunnel from the back looking forward - inverted wing profile with a 12 degree diffuser discharge angle (including vehicle rake).

View attachment 2385

View attachment 2386

View attachment 2388

View attachment 2387
Click to expand...

Incredible workmanship and engineering!
 
They say a couple of things that don’t really sit right with me, but it is interesting.

[ame]https://www.youtube.com/watch?v=3vVimm3y4Ig[/ame]
 
[ame]https://www.youtube.com/watch?v=u-adbpaDLw0[/ame]
 
rtj said:
https://www.youtube.com/watch?v=u-adbpaDLw0
Click to expand...

GSpeed is building some interesting stuff. They are running a C8 and their in-house C5 in the Ultimate Track Car Challenge at the end of the month. This car has no cage (just a roll bar) so it can't run in the unlimited classes - that means it must be fairly heavy to stay in class with the high hp LME motor. It does have some interesting and probably effective aero. Look up GSpeed (Cresson TX). They have tried some wild aero stuff with their C5 and they usually run faster than the NASA T1 times with their T2, very detuned LS. They will probably show up at the UTCC with 600+ wheel horsepower.
 
mfain said:
GSpeed is building some interesting stuff. ......... Look up GSpeed (Cresson TX). They have tried some wild aero stuff with their C5 and they usually run faster than the NASA T1 times with their T2, very detuned LS. They will probably show up at the UTCC with 600+ wheel horsepower.
Click to expand...

Looked them up on the web and checked out their Facebook page. Time attack is not in my budget, but looks interesting.

I thought this car was pretty well thought out.
 
Some details like active flaps in the front splitter, what appears to be wheel cooling fans, and double diffuser.

[ame]https://www.youtube.com/watch?v=4BqjVplGAHA[/ame]
 
69427 said:
rtj said:
Some details like active flaps in the front splitter, what appears to be wheel cooling fans, and double diffuser.

https://www.youtube.com/watch?v=4BqjVplGAHA
Click to expand...

WTF is with that guy's voice? I made it to 21 seconds, and then I had to exit the video.

Any cliffs?
Click to expand...

You could turn off the sound, as he really just points out features. :)

Yes, the voice takes some getting accustomed to, but the cool features I noticed are:

the flaps in the splitter. I’m guessing at high speed on straight line they open to reduce downforce and/or reduce cooling flow(drag). Just a guess.

The outer wheel rim features scallops, which I assume means brake cooling fans and possibly more downforce. That Porsche got more downforce and brake cooling with theirs, granted it was differently designed.

The dual diffuser is there, not sure if they are better, or just allow room for transmission in such a dropped car.

The driving part I pretty much skipped. Oh yes big $$$$$!
 
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