Landracing Forum
Tech Information => Technical Discussion => Topic started by: A2WindTunnel on July 17, 2009, 08:35:20 AM
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The USA Bobsled team (men and women) were in the A2 Wind Tunnel for a 2 day test in preparation for the 2010 Winter Olympics.
Check out this video from WBTV Charlotte.
http://www.wbtv.com/global/category.asp?c=151146&clipId=&topVideoCatNo=128873&topVideoCatNoB=168978&topVideoCatNoC=135991&topVideoCatNoD=139409&topVideoCatNoE=139408&clipId=3958049&topVideoCatNo=128873&autoStart=true (http://www.wbtv.com/global/category.asp?c=151146&clipId=&topVideoCatNo=128873&topVideoCatNoB=168978&topVideoCatNoC=135991&topVideoCatNoD=139409&topVideoCatNoE=139408&clipId=3958049&topVideoCatNo=128873&autoStart=true)
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VERY cool! There are a lot of LSR racers that would love to have access to that tunnel... do you work there?
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VERY cool! There are a lot of LSR racers that would love to have access to that tunnel... do you work there?
I would guess yes he does, if not he is their #1 fan . . . :-D
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if they fart in that tunnel he'll post about it..... maybe slim should see if they'll put up a paid banner...
kent
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He and I have discussed him paying for his stuff. We've also hinted back and forth about how much free wind tunnel time we'll get when we go there with our stable of race bikes.
Thanks for your support, Kent. I've taken all of the old stickers off my pickup -- but I think I've still got some AirTech stickers to put back on it. Just in case I can't find 'em -- have a couple or three with you at SpeedWeek, hey?
Note: Kent has supported Seldom Seen Slim Land Speed Racing in the past. And this website is willing to discuss payments in kind in exchange for advertising -- although cash does go pretty far towards making me smile, too. Thanks to all that have contributed in any way.
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if they fart in that tunnel he'll post about it..... maybe slim should see if they'll put up a paid banner...
kent
I’m on here to help inform as much as I can about aero. Aerodynamics is one of your biggest obstacles to overcome and the least looked at by most of the LS racers. I figured there would be some interest in wind tunnel testing, the types of teams using them, some of the things they learn, so that aero can be better understood by people that don’t understand why there are wind tunnels and how they are used by race teams and what type of information is learned at a test to optimize the aero.
I apologize that I don’t get on here more often to post more “interesting” stuff that appeals to 100% of the group, but do what I can with my busy work schedule. I do try and chime in to answer questions people have about aero on posts and private messages when time allows which I can say is not often.
I thought that there might be some American pride, and interest that the US bobsled team is doing aero development in the wind tunnel before this next year Olympics to get all they can out of their performance, and I wish them the best of luck at the 2010 games. I hope you do too?
If slim has a problem with me on here he has not brought it to my attention, and I welcome him to contact me so discuss it further 704.799.1001. I did receive an email right when I joined LS about advertising (over a year ago) but there was no follow up and got no indication from it what so ever that would constitute “discussed him paying for his stuff”. I don’t recall ever hearing that we would only like you to be apart of Land Racing if you advertise otherwise we don’t want you to post anything or be a member of the site.
I apologize if slim or anyone thinks I’m taking advantage of the website if that is the case, and that was never my intention for joining the site. I enjoy reading most of the posts and builds on here. I thought there would be some value for the members on here to chime in and help educate in any way about wind tunnels and aerodynamics since that is a big part of what you guys are doing.
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......im glad as heck that you post what you can post about
windtunnel happenings.......!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
enjoy ALL of it..........please cont. and dont hold back............
hope to see you soon..........
THANK YOU A2 for keeping us abit more up to speed on aero stuff...
Joe :)
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I agree with Joe,
Keep on posting ....
Charles
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Yeah! Don't let the peanut gallery :mrgreen: get to you!
Mike
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Keep on keepin on.I find your stuff very interesting. Im a MC guy and we need all the help with aero that we can get. :wink:
Fred
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Buy a banner ... it's business ... Joe
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Keep up with the info A2. It's appreciated. Real info is valuable. Aero can be tricky.
Pete
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.........as far as business goes........
its Jon W's call.......and he has spoken here....
for all we know he is negotiating tunnel time....
wouldnt want to ruin that for him...:):)....
or ruin A2's generosity here with aero related topics......
i like any aero related chit-chat......much more than
jokes...etc.......
Joe :)
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I'm with Joe A. Please post aero related topics. I also like your posts more than a lot of other stuff on LR. Our team always wants to learn more and go faster safely. :-D
John
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The one question I had was how much pressure difference between the top and bottom of a NHRA prostock spoiler '' not whose'' your reply was you could not give out information others had paid for.
So much for helping us out.
My reply was this '' :roll:''
JL222 :roll:
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JL 222 seems like I remember Kents "rant" about knock off copying ---how would that be diffirent :? :?
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to me its like if Roush got on here and wanted to help us learn
about making hp and torque...........
talking about cylinder head flow... flow benches......etc....and someone
wanted to know how many cfm a prostock head flows.........cant tell us
specifically but can help us understand some physics.....
or how much positive pressure does a prostock airscoop enable........cant
tell us specifically how much is generated after 50,000$ of windtunnel
and flow bench and bodywork.........but could impart some
helpful hints and guidance.........
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Yes, that's the question you wanted an answer for, however that's not the question you asked. :-D
The info posted so far has helped me go in the direction needed to be safer than I would on my own and I now can prepare for a trip to the wind tunnel and not waste their time and my money. :wink:
Geo
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Go USA!!!! Also, I really enjoy reading about the testing, and also watching the videos on youtube. Please do not take tongue in cheek posts personally, without them the content may get very dry...Just yesterday, I showed a friend of mine the video of the bub liner in your tunnel, and the Saving Abel vid as well to show him some footage of a true dumbass in NASCAR. I mean, what an idiot...
The more the merrier!!!!!!! :cheers:
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to me its like if Roush got on here and wanted to help us learn
about making hp and torque...........
talking about cylinder head flow... flow benches......etc....and someone
wanted to know how many cfm a prostock head flows.........cant tell us
specifically but can help us understand some physics.....
or how much positive pressure does a prostock airscoop enable........cant
tell us specifically how much is generated after 50,000$ of windtunnel
and flow bench and bodywork.........but could impart some
helpful hints and guidance.........
Joea
I'm not asking specifically, if you notice a prostock spoiler they are ran almost flat, so the pressure difference between the top and bottom is were the downforce comes from. In our case, a 10 x 53 spoiler =530 sq in. if there was 1 lb of psi less at the bottom that would be 530 lbs of downforce. If I knew ''approximately'' what it was I could have more info to lobby for a rule change to allow longer spoilers. 5 more in. at 1 lb psi
= 265 more lbs or total of 795 lbs. This would allow us to remove weight and kinetic energy.
Then there is Gurney flaps.
Maybe somebody here knows this info, or a prostock crewchief.
JL222 :cheers:
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The one question I had was how much pressure difference between the top and bottom of a NHRA prostock spoiler '' not whose'' your reply was you could not give out information others had paid for.
So much for helping us out.
My reply was this '' ''
JL222
All I can say is that I try to help as much as I can without getting fired from my job and (I hate to say) as politically correct as possible to keep all parties satisfied. You NEED to understand there are confidentiality agreements that we sign with teams that test in the tunnel and if I were to talk about something learned at a test I could lose my job and could potentially have a law suite against A2 because of a little piece of paper called a contract. We take this VERY seriously at both tunnels ( AeroDyn & A2) and don’t care how many stick and stones thrown or eye rolls I get, I will NOT talk about other team’s data or information with out permission from them because that is information they paid for their personal use. There is a reason that more wind tunnels are not on here writing about information because they don’t want to deal with walking a line of what they can talk about and what they can’t then getting slammed for not telling someone what they want to hear. I am walking a fine line by being on this website to not give our customers the wrong idea. If I were a University student of professor that had access to a wind tunnel that I could run my own studies then that is a different story.
I can talk about general aero related questions and have been pretty specific in the past about some posts. If you have a question about a configuration any team has tested then that constitutes information that a team paid for to find the answer no matter how general you think it is. Are there some questions I can be more specific on? Absolutely. Do I have the time during my day to spend hours on here to answer all questions in the way they deserve in great detail? NO, but I know that for every person I do answer there will be one or more that is mad that I didn’t answer theirs in the way they felt I “should” answer.
There is no magic number for me to say well in the history of the NHRA 100% of pro stock spoilers have X amount of pressure difference from top to bottom. Bodies change, rules change, different manufactures have different things going on with the shapes of the car, scoops, spoiler angle, spoiler with wicker or without, underbody, fender shape. Even the lateral and longitudinal pressure distribution on a spoiler is not the same from left to right. With so many variables there I can’t just say X is the value you are looking for. If you think that is no help then you are not paying attention to what I am trying to educate you on. ALL of those variables will make a difference in the pressure reading you are asking for so I cant be general because I would have to tell you more information then just a single number. You can’t assume that one car has this aero characteristic so my car must be the same since it has 4 wheels and a spoiler. And that 1 single number will represent the pressure difference on a spoiler is the same for all is not a good assumption.
I will ask a similar question to you that you asked to me. What is the pressure inside a balloon? Or have a look at this picture and tell me what single pressure best describes the loading in the wings of this aircraft?
(http://www.aerospaceweb.org/design/psp/images/psp-cfd-comparison.jpg)
If it is a general question then please be a little more specific in what you want to know and why and maybe I can give you a general answer without a breach of my contract. I guarantee that the pressure difference is not the same as on your car as it is on a pro stock, so if this is something of great interest to you and you want to know the answer to help you better understand what is going on with your car then I recommend you do what all racers do.. R&D. Find a way to measure what is going on at the EXACT location you want to know so that you can get on here and tell all of us. On this (Year) (model) car in this (detailed) configuration at this location x inches behind and x inch below the rear spoiler at this angle and this dimension. This is the pressure I recorded. If you need help on how you could do this, I’m always available to help the best I can (give me a call) I might be able to be a little more specific on the phone then in an open Forum.
I appreciate the positive response from most of the members that I have got in phone calls and email. I will continue to help as much as I can, and if some of you expect me to just give out information because you feel you deserve them, then you are mistaken and I am not on here to give away information or something you might think of as general, but I signed contract stating that I would not talk about because someone tested it in the tunnel. Put it this way… If you came to the tunnel and spent $5000 to learn and develop your car, would you be okay with me getting on this forum and openly talking about your test, what you did, what you learned in detail? I think you would want the same respect I give all our customers.
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I understand your position compleately. As I said before thanks for what you can and do put out. Here is a short question, roughly speaking how much slicker, aerodynamically, is a well waxed surface.
Fred
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very cool stuff.....hopefully we can get jl22 closer
to the understanding he is passionate about .....
as it can be so useful for so many...
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I understand your position compleately. As I said before thanks for what you can and do put out. Here is a short question, roughly speaking how much slicker, aerodynamically, is a well waxed surface.
Fred
Depends on if it is a Car (bluff bodied object) where the pressure drag far out weighs the skin friction drag. In this case you might see a very small measurable difference (depending on the car) but it would be very small improvement if any. Say your skin friction accounts for 5-8% of the overall drag and waxing helps that % by a small percentage. Now you are talking about a fraction of a % improvement.
If you have a streamliner skin friction becomes much more important because it accounts for bigger % of the overall drag of the vehicle. Things like wax could be more of an improvement on this type of vehicle.
I can talk about this. I have seen NASCAR racecars in the wind tunnel with paint, primer and bare metal and it is not a significant change in drag because the pressure drag dominates the skin friction on those cars. I have also seen a team spend hours waxing a car to only have the data repeat from the previous non-waxed run. Hope this helps.
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if they fart in that tunnel he'll post about it..... maybe slim should see if they'll put up a paid banner...
kent
I have been at the tunnels for 5 year and have tested over 15,000 hours with racecars and can tell you that for every "fart" I write about there are 2000 that I cant talk about.
I can tell you that there is a low pressure area where the bobsled crew sits and if one happens to fart... it will stay in the compartment with the others during a run. This was confirmed in the tunnel with a smoke wand and by the team if you get my drift...
:-D
.
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I wish I had your answer before I spent most of the afternoon waxing my bike body stuff.lol Oh well it sure looks better. :-D And thanks for the help.
Fred
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I'm not asking specifically, if you notice a prostock spoiler they are ran almost flat, so the pressure difference between the top and bottom is were the downforce comes from. In our case, a 10 x 53 spoiler =530 sq in. if there was 1 lb of psi less at the bottom that would be 530 lbs of downforce. If I knew ''approximately'' what it was I could have more info to lobby for a rule change to allow longer spoilers. 5 more in. at 1 lb psi
= 265 more lbs or total of 795 lbs. This would allow us to remove weight and kinetic energy.
Then there is Gurney flaps.
I am always happy to help when it comes to safety and other info and all of this information should have been part of your original question. Again, Aero is not that simple to assume that everyone would benefit from this and x psi on a pro stock would be this much lbs on your car. If it were that easy us wind tunnels would be out of business.
I can say this.. In my opinion (take it for what it is worth) I always have a difficult time with a rule or safety change without any empirical data to back it up. You’re assuming that this extra downforce would be great, but the force changes with velocity squared. Is that 265lbs more at 100mph, 200mph, 300mph? Is the car producing lift on the front? Will this added rear downforce create a moment on the front that would produce more lift making it unstable or even airborne on the front? These are the types of questions that need answering and I say this in a lot of posts, but NO 2 Racecars are the same. Without testing you can’t assume a result for every type of car out there, and things you do to the front or rear of a car aerodynamically can affect the balance of the other end.
There are plenty of LS racers that come to the tunnel. If it is a rule change you guys are looking for then maybe you could ask each of them that would be willing to get a delta pressure across their spoiler to establish a data base for the different style cars to base any decisions on. Or see if someone is willing to run with a longer spoiler to see the affect on their car. This is easily done in the tunnel by adding an extension to an existing spoiler.
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Team USA won a Gold medal in the 4-man bobsled after a 62 year winless streak!!
(http://www.bodynbobsled.com/UserFiles/Image/4manGOLD-2010Whistler_web.jpg)
Read More at:
http://www.bodynbobsled.com/ (http://www.bodynbobsled.com/)
D
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I watched NASA spend a day testing metal pucks of different metals for the bobslded runners at a skating rink in Cleveland. They would launch them off a platform and see how far they would slide. They had all kinds of different coatings on them but wouldnt discuss anything. Yes that NASA, your tax dollars at work
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Years ago I worked for a composite and geometric design firm here in Greensboro NC called Envision: Concept Developments. We had a contract with the US Olympic Committee to build tool and produce beta bobsleds. They had them tunneled somewhere in NC perhaps that was you?
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My nephew John Daly was USA-3 on the Skeleton Bobsled Team ... finished 17th overall at Whistler. He constantly works on aero relating to shoulder and head position.
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I believe Park City Utah is the headquarters for the team. I know the driver lives there. It is less than 3 hours from the salt. It sure would be great if they could bring a sled over for a day during Speed Week. Maybe sell some t shirts? On tv they didn't show much of the bottom of the sleds; just a quick shot or two as they were flipping them right side up to run. It looked like they had some very interesting "aero" on the bottom!
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That would be great......I would love to see one the Bodine Sleds. These guys did one heck of a job. Rich