DSR Downforce
Does anyone have any data or anything on the downforce generated by todays DSR's? Any speed is fine, I can scale it. I made some pretty accurate CAD models of the top competitiors and ran 3d CFD tests on them, and Id like to do a comparative analysis on the simulations. We do this sort of thing with our FSAE cars, but the main difference here is I dont have a DSR at my disposal! Thanks!
R
Lots of downforce on the top ones with full undertray ground effects aka: diffuser
Contact Rennie clayton at Dauntless Racing as they offer a complete upgrade kit and run CFD on their aero work. They probably have actualy figures from their clients data systems but that would be confidential, I am sure you can understand that. http://dauntlessracing.com/
Kevin Firlein Autosport,Inc.
Runoffs 1 Gold 3 Silver 3 bronze, 8 Divisional , 6 Regional Champs , 3x Drivers of the year awards
Raneff5, I have seen a DA dump that indicates 3+ G lateral, steady state cornering. Coming from FSAE, you should be able to plug that into your simulator of choice and get a ballpark value. Your results might vary.
Marty
Wolf GB08 makes 1750 lbs of DF at 250 kph
I have seen 3.8 gs on a DSR that won the Runoffs in a fast corner of course) The car weighed about 1000lbs. I know the G's and you get to figure it out.
Jay Novak
Last edited by Jnovak; 12.23.12 at 12:53 AM.
DSR Downforce
Lets see how 'lots' works in the computation.....Originally Posted by Steve Demeter
Honestly, Im just looking for a verified number, unless someone really wants their data analyzed. Unfortunately, backing it out of just a vehicle weight and lateral aceleration would barely me close to a ballpark figure. Fortunately, scaling DF via speed is very accurate, which is why any speed will do. This is just for a comparative analysis so we can quantify the lift to drag ratios of something like an open wheel FSAE car vs a closed body car in the real world.
If someone has some info and doesnt wish it to be public, PM me, I can guarantee the number won't see the light of day. Thanks!
Edit: turnbaugh, Thanks! the wolf GB08 is definitely bigger than a DSR, no? That amount of downforce makes sense for something a bit larger at those speeds.
I'm curious how you can have "pretty accurate" models without access to a car. Can you glean that much from photos?
ESPN. The coverage is excellent, you'd be surprised at how much you can pick up.
The GB08 weighs 1150ish with the Honda K20 and the Sadev.
CSU grad here - go Rams
My numbers aren't quite the best of the best in DSR, but in the carousel at Road America, my best numbers show about 2.9G @ 112mph. That's the only real high-G turn I've got in sea-level air
Stohr WF-1 at around 1030# at race's end, so it would have been somewhat more than that during that, perhaps 1050# or so.
That seems to correlate OK with my FB, which shows around 2.45g @ 105mph in the carousel, which is also not among the best I don't think. Post-race weight about 1020#, so probably 1050# or so also for that exact measurement.
Drop me a line if you like,
-Jake
ESPN... Hardy-har-har you guys! Ive modeled them based some local cars I took measurements and such off of, and gotten the outer body shapes as close as I can to photo overlays on the CAD models. Its pretty standard stuff. Obviously I havent done anything past the standard aero devices - nothing like the Dauntless stuff.
Jake - Ill PM you
An additional data point that is needed for the downforce calculation: Current FF tires produce 1.9g lateral with no downforce.
Exactly. I actually have some tire data that I could use, but again, to make that work I'd need a whole lot more info!
Try to get data from the last three Swift FAs. They have data from wind tunnel work. Also see if you can get the Lala T97 data or the Dallara Indy Lights data.
As a guesstimate you can say the car will make down force equal to the car's own weight at 150 mph. That should be distrubuted front to rear at about the car's weight distribution. The DSR has the hp to go 150 mph.
Are the DSR aero numbers a moving target with the introduction of turbo engines?
Brian
In general, most of the DSR data above is from Road America which, because of it's long straights, is considered a low drag, low downforce track. The aero package would change if the runoffs moved.
Also, last year's DSR winner was a turbo 670 cc which had an observed / claimed / guessed at top speed of 180+ MPH. This didn't appear to change it's corner segment times.
A treasure trove of sports racer tech:
http://www.mulsannescorner.com/
I have frequented that website for years! I assume you mean this:
http://www.mulsannescorner.com/data.html
Still, its not directly proportionate or applicable to DSR's...
Very cool site
"An analog man living in a digital world"
Any reason why you've posted this question in a formula car forum instead of the sports racer forum? I'm not suggesting that the info you're getting here is wrong, but if you want DSR info, why not go to a DSR forum?
I asked the question on the dsr forums a while back, but Apexspeed is more organized and thought someone might know!
OK I'll jump in,
The LSR-II is fairly tunable in terms of total D/F by using wing, ride height and angle of attach.
In the highest d/f configuration around 1600#'s at 110 mph (waterford hill setup). Lowest 1270 at 130 mph (RA setup) Measured using LVTD's not strain gauges.
So your numbers are calculated, not measured, correct? Those numbers sound reasonable.
They are based on shock diplacement which is measured and then calculated based on springs and motion ratios. We did do a test by adding weight to the car on the scales and verified that the math channel is working correctly.
Not as accurate as strain gauges but still a very reasonable way to find df distribution.
Mike, Thanks for the info! that's one of the ways we measure actual downforce as well.
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