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#21
17-09-2012
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To answer a few questions ...
... the Golf is a '83 series 2 mk1, is currently under restoration and belongs to Dan ... Like Matt said, the tunnel is a sucker not a blower ... don't think that's the technical term tho !! The drag question ... um .. well not sure on that one just yet. For now I want to keep the wind tunnel as simple as poss and try to get it working as consistently as we can so that we can measure downforce with some degree of accuracy from model to model. Thanks for the ebay link, its on my 'watch' list !! Thanks to everyone for the tips and links, I look at all of them .... it's been a steep learning curve so far and I think the hardest part will be collecting the data and applying it to something useful that can be used positively on track .... again any suggestions are much appreciated !! 
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#22
20-09-2012
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Quote:
Have you tried using 4 scales (one for each wheel)? That's how most real tunnels work. What sort of repeatability do you get? This is always the hard part ;-)
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#23
20-09-2012
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Thanks !! Very cool job
 To be honest I haven't even finished building it properly yet ... should really get off the PC and go do it !!! .... Whats the advantage to having a set of scales per wheel instead of just one per axle ? I can't really answer about the repeatability, when the tunnel is finished we can test parts a bit more seriously and will find out how accurate it is 
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#24
21-09-2012
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Quote:
With a real tunnel one pad per wheel is just easier to engineer I guess, plus there's usually a rolling road in the way to complicate things! Keep us updated, look forward to seeing some results 
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#25
01-10-2012
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After having a long chat with Si & Dan at WORM yesterday about their basic initial tests & findings with F & R wings and their positions, i think people are going to be suprised at just how efficient certain wing and body shells are ( or arent ) and what they do to the airflow for F & R lift and downforce. Or dont do, as the case may be....
Roll on winter when they have more time to do some more testing and show some spreadsheet results
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#26
17-11-2012
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There is another method I've used which is great for photography but only good for stuff that doesn't mind getting wet, like bodyshells. If you've got a white bath, rig up a cheap adjustable strobe light, and move the bodyshell slowly along the bottom of the bath in just enough water to cover it. (glue a small stick to the roof) Adjust the strobe light until you see a nice flow stream over the bodyshell. You will see where the vortex's are forming but obviously you won't be able to measure the downforce. A nice angle without any turbulence will be between 12 and 20 degrees.
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#27
18-11-2012
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Nice tunnel have a look at this
http://www.youtube.com/watch?v=mpMOpyLbjcA Uses 5 digital scales. open fan design with boundary layer suction very cool. But then the guy did the gesign work on the nissan P35 and Nissan r35 gtr so it probably child play for him. http://www.suzukaracing.com/
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#28
19-11-2012
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Thanks for the input guys ... already studies the vids ... this ones interesting - http://www.youtube.com/watch?v=DpzRP...hannel&list=UL
We're on a re-build at the moment, nothing too technical, just a little more accurate construction than the first version. Hopefully with a stepped speed controller to change the wind speed as its fixed at 25mph right now. Seemed a good idea at the time, but on reflection, this is prob a little on the high side to be a good representation of an buggies average speed. Anyone got a good idea of a buggies speed around a track ?
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#29
19-11-2012
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Track length at WORM is about the 145m mark from memory (might be longer now, but can't remember precisely...must get Kev to walk it again with his wheel sometime!)...best laptimes shown on our website results come in at around the 25 secs mark...do some simple maths to get a rough idea of an average speed!
145/25=5 metres per sec 5x60=300 metres per minute 300x60=18,000 metres per hour = 18km/hr = 11mph average over a lap! Maybe you should start out by finding out what speed the aero design actually comes into play and is effective! That would tell you at which points on a lap it could have the biggest impact.
__________________
AKA: Andy Nancollis 1/10th drives: Yokomo BMax2MR & BMax4 1/16th drive: Carisma GTB Racing in South West: http://www.mendiprcraceway.co.uk/ Racing in Wales: www.caldicotrcracers.co.uk Kept running by: Yokomo via MB Models & www.tracksidespares.co.uk Shells by Square Crabs
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#30
20-11-2012
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Wow that's low ... not what I expected. Sounds like 25mph is too high for a relative downforce reading really ... maybe on the straight ... but won't really apply to majority of the track.
We're looking into an Iphone app that determines speed ... think it's for mountain biking ... could be useful !!
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#31
22-11-2012
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Aren't wings really to stablise the car in the jumps?
You would need the launch angle peak height and mass and a equation of a projectile http://en.wikipedia.org/wiki/Trajectory_of_a_projectile if you know what the drag is you can resolve for launch speed fairly accuratly.
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