Wind Tunnel Smoke Testing

[Beairsto Racing]

I'll stick in a bit of comment.  Dave and I have talked about me visiting the A2 tunnel so I can write a bit about what goes on in there when a bike goes under the test program.  I know that Dave Owen and Lee Sheirts once went there -- and some story was generated, but I don't know if it reached print or was just anecdotal around the pits at Maxton.

Whatever -- one of these days I'll make the trek and get a visit down on paper.  I'd take one or two of our bikes -- but that's quite a logistical project for us, so maybe just a visit will have to do.  Stay tuned.

Jon, the wind tunnel story with Dave and Lee was in Sport Rider magazine a few years ago.
If I were home I'd scan it and send it to you, but I'm in Saudi right now.
Maybe someone else has it and can post it.

Cheers,
Scott

[Seldom Seen Slim]

Scott:  Yeah, now that you mention it - I do remember the article.  Still -- another one won't hurt A2's efforts to generate some public knowledge about their business.

Speaking, though, of Sport Rider magazine -- it's time to get cranky at Kent Kunigutsu, the editor.  I hear that he's tired of getting requests to publish articles on land speed racing bikes -- even though you and I think there's some good technology (and good stories) that's worth sharing.  So - if you happen to agree with me and want to take a chance on getting a magazine editor cranky at you -- drop a line to him (I guess they've got a website, too -- you could do it be email) and ask for LSR content.

End of soapbox rant.

[Rex Schimmer]

The sprint car was interesting but as has been stated the air flow when the car is going straight is of small consequence for the way that the car really runs. The tall side board on the cars left side (looking forward) is what provides the cornering down force and roll moment when the car is "backed into" a turn really hard and at that angle the actual wing is probably not generating much down force at all. I was impressed that the air on the bottom of the wing, at least between the mounting structure and the side boards, appeared to be pretty well attached to the wing, this is where aero down force is made. It is the bottom of the wing that makes the down force by having higher velocity therefore lower pressure than the top of the wing. It was pretty ugly in the center because of all of the tubing of the support/adjustment structure. Interesting when the smoke was ran long the left side board (again driver's left)  and the low pressure from the attached and high velocity air on the bottom of the wing drew the smoke around the side board and into a trailing votex. Didn't see this on the right side because the side board is much longer and prevents this spilling of air to the low pressure under wing.

Back in the 80s (here I go again showing my age!) there was a guy that ran at Knoxville that had the wing "skewed" so that when the car was backed into a corner the wing was pointed in the direction that the car was actually going. It actually was pretty fast.

Rex

[WildBro]

Speaking, though, of Sport Rider magazine -- it's time to get cranky at Kent Kunigutsu, the editor.  I hear that he's tired of getting requests to publish articles on land speed racing bikes -- even though you and I think there's some good technology (and good stories) that's worth sharing.  So - if you happen to agree with me and want to take a chance on getting a magazine editor cranky at you -- drop a line to him (I guess they've got a website, too -- you could do it be email) and ask for LSR content.

End of soapbox rant.

Were did you hear this Jon?

Bill

[mtkawboy]

Jon, I have that magazine, its Sport Rider June 2001 with the Hayabusa vs ZX12R wind tunnel test. I have no way to scan it but will mail it to you & ask only that you send it back to me

[joea]

the busa zx12 windtunnel article is a different one than the a2 article...

the 2001 article was in a canadian windtunnel..

[A2WindTunnel]

A2WT didn't open until the spring of 2006.  This is the cover of the mag they are talking about.

[bak189]

The Busa/ZX12 was done in the tunnel in Canada.......same tunnel that Can-Am used to do back way back when!!!!!!

[Freud]

bak....that's info from so far back most have no idea.

Pretty good OLD DAYS, weren't they?

CAN AM 125cc.....wowser!

FREUD

[blackslax]

With all due respect, we need to tuft the areas behind the canopy and tail first.  When we have eliminated all reversed flow, then and only then should we worry about what is going on upstream; i.e. the canopy leading edge.
[/quote]
One thing I learned a long time ago is to always find the smartest guy in the room and if it is not you, pay close attention to what they say. 

Comment about the yarn, spot on. 

Comment about the air after the canopy, spot on.

As an F1 aero guy told me a few years ago, "getting the air apart is easy, putting it back together is hard part."  The canopy front will have high pressure, that is inevitable.  Poor canopy design that causes reversal of flow is correctable.

One other F1 test method that you can employ is it mix fluorescent dye in mineral oil and put it on the vehicle in drops and pools.  After a lap or two, they can see where the air is going and pooling. (Kind of like the "art" they made on Top Gear.)

[saltfever]

edit . . . Interesting when the smoke was ran long the left side board (again driver's left)  and the low pressure from the attached and high velocity air on the bottom of the wing drew the smoke around the side board and into a trailing votex. Didn't see this on the right side because the side board is much longer and prevents this spilling of air to the low pressure under wing. Rex

I was confused by Dave's reply no. 34. He seems to indicate he would expect a vortex but there was none. However, you are right . . . that vortex on the left was beautiful and rotating in the correct CW direction. There is also a vortex on the right, first showing up at 2:43 seconds. It is well defined and rotating in the CCW direction and continuing for about 35 seconds longer.

[saltfever]

Dave, I don't want to minimize the quality of the work and your videos. The videos are great and sharing your work is tremendously appreciated.

[A2WindTunnel]

Here is another wind tunnel smoke video

'71 Dodge Daytona
http://www.youtube.com/watch?v=7Xc5TjtZh34



From the site www.71wingcars.com
"Gary & Pam Beineke built their 1971(G-Series) wingcars based upon results from a secret wind tunnel test report Chrysler had conducted in early 1970 on the new 71 Dodge and Plymouth B-bodies.  No full scale cars were ever built...until now." 

After the build Gary and Pam brought the car into A2 to get some baseline data and also developed the aero of the car further to improve handling for landspeed racing.

[Hans Blom]

can your tunnels rotate teh front wheel on a motorcycle? seems the pumping of air is very important to the drag racers but doesn't get talked about here much. Seems air being thrown forward into your oncoming air and how to control it...or increase it depending on type of bike being ridden..would be of a high prioroty.

Hans

[Seldom Seen Slim]

I know that the concept of spoiled aero from the rotation of the front wheel has been discussed and even experimented with -- but probably not on this thread.  With the SCTA rules on front fender there's only so much that can be done -- but Kent Riches at Air-Tech makes a nice slick-looking front fender that should improve on the standard front fender.