Landracing Forum
Bonneville Salt Flats Discussion => Bonneville General Chat => Topic started by: Larry Forstall on February 16, 2011, 10:54:52 AM
-
On Valentine's Day I took my baby to the A2 Wind Tunnel. She brought along a friend. Having to drive across the country to race for decades the East Coast has the advantage of a convenient, economical (for a wind tunnel) testing facility. We learned a lot and I must thank David Salazar for his patience as we asked many questions. I can now see why the Nascar teams test frequently. Every change has multiple effects. We made drag reduction gains that would be impossible to accomplish with HP (The Guppy is a N/A bike). This is the 21st century and air management testing is as important as the engine dyno. The 3000 HP electric motors drive the fans at 85 mph. Each test takes 3 minutes and the rider must not move. Standing in the tunnel as the wind is sucked by you is an unique experience. I'm hooked, can't wait to see what the salt thinks this summer.
(http://im1.shutterfly.com/media/47a1dc37b3127ccefc3571cbab3900000030O00AZNWrhk1aOGIPbz4e/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/)(http://im1.shutterfly.com/media/47a1dc34b3127ccefc0ae74a63c400000030O00AZNWrhk1aOGIPbz4e/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/) (http://im1.shutterfly.com/media/47a1dc34b3127ccefc0af92ee29f00000030O00AZNWrhk1aOGIPbz4e/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/) Bill Warner's 278 mph mile bike.
-
Thanks again for sharing Larry, beautiful pics. I can hardly wait to see how fast these bikes are this year. :cheers: -Dean
-
I got to go out and gofer for these guys. Never has a gofer had more fun or learned more. It was a unique experience. :mrgreen:
Fred
-
Here is a little smoke
-
Getting ready for the first pull. OOPS first pull
-
Going to A2 is the best money you will ever spend on your car or bike. We recently took a very special and unusual project for a friend. We started with a 1000 lbs of lift. We left with over 300 pounds of down force on the front. As well as reduced drag about a 100 Hp. Drag is important, but lift is even more important in my mind. Getting light usually equals a spin, which can be very expensive and dangerous.
Will post a pic when I get time
Steve
Jack Rogers Racing
-
Thanks for sharing, very, very cool stuff!!!!
Yep, lift on a bike is not good. I think it might have contributed to one rider going down at Texas.
-
very very cool, thanks for the share. :cheers:
-
The pics are great, thanks for sharing. Can you tell those of us who are aerodynamically challeged what changes you made that the wind tunnel revealed?
Thanks,
Don
-
Great stuff guys. Thanks for all the pics. 8-)
-
The pics are great, thanks for sharing. Can you tell those of us who are aerodynamically challeged what changes you made that the wind tunnel revealed?
Thanks,
Don
I'm sure he could post the knowledge they gained. but why would he? They spent thousands of dollars to go to the tunnel and test. He would be nuts to give that info away for free IMO. That's just my .02
After all, we are racing... :wink:
-
About sharing information. Rest assured the guys at A2 WILL NOT share secrets or tricks. They will help guide you and help you understand the basic principles of air flow. But that is as far as they will go, confidentiality is very important in there business.
-
Ok, so the post was not to share information, but just to make us jealous instead. It worked.
Don
-
Does A2 have the tufting yarn/tape on hand?
-
No you have to supply your own yarn and tape. Actually takes some time to put on. Don: Unless we both had exactly stock bikes and identical riders most of the information learned only applies to the test vehicle. I can confirm that bikes have marginal front downforce. The reason we went to the tunnel was that the Guppy chunked a front tire at speed. I had added front weight and I thought it and downforce caused the tire problem. Close inspection of the tire and the WT data make me pretty sure we just ran over something. Most know the old Daytona trick of lifting your butt to add speed. I have used it in the Production class; on the Guppy it does not work. What we learned is to not assume anything; it might seem wrong but try it, you might just go faster. Larry
-
To Maximize Tunnel Time and Data (number of Blows per hour etc..)
You need to do a bunch of stuff before you get there.
1. Tape and Tuft before you load your bike or car.
2. Mock up any items you wish to test (spoliers, air dams, scoops, fairing, step pans etc) all before you load up to go to A2 WT
3. Bring SEVERAL rolls of tape, lots of card board and or sheet alum, cordless drill and rivet gun and rivets.. or whatever you wish to fasten with.
4. Have help with you (not casual observers) not enough time or room to party,, this is a work day.
5. HAVE A WRITTEN PLAN AND CHECKLIST
Enjoy the day,,,,
Charles
-
I have a few questions for you, nothing about your specific bike,
When you went there was there anything you thought you were going to use / need / or do that you ended up not?
How many runs did you make?
If you went back what would you do different?
I have no idea what you can do in your class but what did you end up changing?
If you added things or shape to the bike did you leave the tuffs on the entire time?
What advise would you give somebody that will be going?
-
James J answers:
I thought we would adjust the ride height or angle but didn't.
Ten
More of the same. Once you start and see the results the
next test becomes obvious.
Changes made = confidential
Yes, tuffs were on for all tests.
Follow Charles' advice above.
-
those guys at a2 are great ! stoped by there in aug . on a buying trip in mooresville ( stock car auctions ) they gave us the tour and explained everything . taking car there when we are close to done.
-
Thanks for the reply Larry,
I was just trying to get an idea of what actually happens while there, as far as changes I guess we will see them in August!
Do they video it? and then can you get a copy?
-
To Maximize Tunnel Time and Data (number of Blows per hour etc..)
You need to do a bunch of stuff before you get there.
1. Tape and Tuft before you load your bike or car.
2. Mock up any items you wish to test (spoliers, air dams, scoops, fairing, step pans etc) all before you load up to go to A2 WT
3. Bring SEVERAL rolls of tape, lots of card board and or sheet alum, cordless drill and rivet gun and rivets.. or whatever you wish to fasten with.
4. Have help with you (not casual observers) not enough time or room to party,, this is a work day.
5. HAVE A WRITTEN PLAN AND CHECKLIST
Enjoy the day,,,,
Charles
Tufts. Lots of 'em. Gotta love it.
Awesome work on the bikes, no they are not going to tell you what they did or found out, Charles' checklist is perfect.
The areas of attached and detached flow on the riders' backs is very interesting. I'd be curious how moving the seat pad up to make the rider's back flatter affected this. I am very impressed by thge little spoilers on the helmet getting the air to fill in behind it. That's going to be pretty head-angle critical...
Next thing I'll toss into the mix is that last year we switched from high shutter speed stills to GoPro mounted on the aircraft. At the highest frame rate we were able to quantify for the first time the degree of instability in waving tufts. Of course, aircraft have wingtips that are far from the areas of interest and allow good fields of view. A companion rider on a bike in the next lane could do the same.
-
Larry is the engine and exhaust operating during this testing .
-
Larry is the engine and exhaust operating during this testing .
good question.
franey
-
No, the engine is not running. Nascar has done a lot of research trying to find an aero gain with the exhaust flow but because of their rules can find nothing. In contrast F1 has made big gains the past few years.. Larry
-
Larry
your tufts were way to long that's why the laid flat and wiggled at the ends... cut them to about 3/4 of an inch and you'll start seeing separation points as the tufts lift and turn back instead of just lay down
Kent
-
It is a planned pit-stop and all the pros practice before the race! Try to stick to your plan but be prepared to shift gears if the results are not what was expected. Be sure to have a base-line to compare all results to even if that means you do all the add-ons and then one last pass with all the "improvements" removed! It is easier to take stuff off than it is to add it in the tunnel!
Graph the results - we are visual - not so numerical! If you are no good at MicroSquash Excel I can graph stuff on the cheap - pm me!
BTW: May 2008 Racecar Engineering has a very good article on wind tunnel prep:
http://gb.zinio.com/browse/issues/index.jsp?skuId=254971740&pss=1