Phat wind tunnel

[mrspeedy]

It all started off with a a hair dryer, a wing, a piece of plywood and set of digital scales .... not exactly hi-tech but it was pretty clear from the readings we got on the scales that there was some potential in building a slightly more sophisticated wind tunnel ....

So we did ... it's not finished yet by some way and we're learning what does and doesn't work as we build it but the final version should allow us a good insight into what aerodynamics do on a RC car

Piccies ....





























More pics and details to follow

[Rebelrc]

Nice work!
Looks ace and interesting results should follow
Excellent Mr speedy
You can get smoke pellets or smoke matches for chimney testing at most plumbing stores
Hth's

[colsey2009]

your one busy man!! looks brilliant

[Sparky]

I used to build lots of small wind tunnels. Believe me smoke is not the way to go. We tried allsorts of smoke from burning cardboard to that smoke mixture for stage productions. All of these end up filling the room with smoke quite quickly. In the end we used the finest thread attached to a thin piece of steel wire.

HTH

Sparky

[Rebelrc]

Or you could just vent it outside

[mrspeedy]

We've only done a few basic trial runs with the wind tunnel and the data collected so far is from the digital scales mounted under the front and rear axles and is proving reasonable accurate ...

I'm pretty sure we will test some sort of smoke .... was actually thinking of a smoke pellet in a barrel with a small bore flexible line to draw the smoke up to some sort of wand in the wind tunnel ...

I don't think the smoke will hang around in the workshop too long tho, the fan at the end of the wind tunnel is around 16" dia and draws air at 25mph !!!

[The Chef]

Cheeky little MK1 Golf in the back ground what year is it?.

[Delboy]

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.

[smokes]

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/

[mrspeedy]

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 ?

[blue_pinky]

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.