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?.

[sosidge]

Great project!

[metalmickey0]

Originally Posted by The Chef

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

Ask Dan as its his and i think he has two of them and a polo.
Its so low he has trouble getting it off the drive

[mark christopher]

se this for controled smoke

http://www.tlc-direct.co.uk/Products...FUNTfAodgkIAaQ

[androo]

hi there.

I'm really liking the wind tunnel, it's a great project.

Just one question, have you thought about pointing the car towards the fan which would give you aerodynamic loads for the car going forward not backwards??

[Dyna]

Originally Posted by androo

Just one question, have you thought about pointing the car towards the fan which would give you aerodynamic loads for the car going forward not backwards??

If you look at the fan blades, Si is drawing the air in from the multi-tube end over the car and out through the fan, not blowing it directly over the car from the fan end. This would cause turbulence and localised areas of higher pressure, unless the fan was further away and/or the air was channeled to smooth out the airflow. What he's done is the best way for the working area & the fan he has.

Nice going Si, you've talked about it for ages, good to see it working

[mattr]

Can only see two sets of scales. Why arent you measuring drag too. Almost as important as downforce!

Or is that on the long list of things to do?

[metalmickey0]

Originally Posted by Dyna

If you look at the fan blades, Si is drawing the air in from the multi-tube end over the car and out through the fan, not blowing it directly over the car from the fan end. This would cause turbulence and localised areas of higher pressure, unless the fan was further away and/or the air was channeled to smooth out the airflow. What he's done is the best way for the working area & the fan he has.

Nice going Si, you've talked about it for ages, good to see it working

Si does indeed have the fan sucking air throo and not blowing and its abloody big fan aswell as seen it for real. Imagin the size of your dustbin lid and you got an idea.

[stoff]

Ace! I did my Uni degree project on RC aerodynamics using a wind tunnel. You'll be amazed at what happens to the air as it hits the car.

I chopped a shell in half lengthways and mounted it to a board. I used special fluro paint that stuck to the board showing the affects of the aerodynamics.

[Tomk26B4]

Originally Posted by stoff

Ace! I did my Uni degree project on RC aerodynamics using a wind tunnel. You'll be amazed at what happens to the air as it hits the car.

I chopped a shell in half lengthways and mounted it to a board. I used special fluro paint that stuck to the board showing the affects of the aerodynamics.

I saw people at force India using what looks like the same stuff when I was there on work experiance, its really amazing what shapes and patterns it leaves.
would love to see any results, especially if you test any forward cabs to see what the difference is?

[D20MCK]

Originally Posted by mark christopher

se this for controled smoke

http://www.tlc-direct.co.uk/Products...FUNTfAodgkIAaQ

Don't buy this stuff, it's for testing smoke detectors. You can hardly see it when it comes out the can. I use it just about every day of the week.

[RickRick]

how about removing the pinion, and the back stop, and replacing it with a small spring gauge, and a small wire to teather the car, and measure drag liek this http://www.ebay.co.uk/itm/Newton-met...item3a60847f50

[hotrodchris]

F1 uses the paint approach so why not go that route applying it to key areas of the shell ecetera and see results as it can be studied before cleaning as smoke is instantanious so you may miss something?

[Rebelrc]

Video.