Active aero!

In reply to Keith Tanner:

Nicely done!

These little guys make for excellent actuators in many applications. Here's a little video demo of how to make them do your bidding:

http://www.youtube.com/watch?v=EuQrtwljUKc

Saw your other test video not too long after you posted it, I was waiting for you to make a thread here, my friend figured you were waiting for a track day to test it. Nice work!

I'm having thoughts!

Nicely done!

Did anyone mention vacuum actuation? Maybe even straight pneumatic. Might be faster.

There are many ways to make this 25% better, but they're all 1000% of the cost.

Teh E36 M3 wrote: You didn't happen to disable for a few laps for comparison? That would be some great data to have.

Of course! I did a direct before/after. And the Traqmate says I was doing -3353 mph. So I have no actual data at this point, that will have to wait for a few weeks.

This was a proof of concept. Concept: proven. The custom-programmed controller with GPS activation is not something you try on the proof of concept For the proof of concept, you hook a relay up to the brake lights. And I have to say, it works pretty damn well.

I've got a more programmable pair of linear actuators on the way, on loan from a Miata owner. They'll let me try out my three-position setup. The custom Arduino setup will wait a bit longer. Of course, first I need to install an improved drag compensation device, in the form of a bigger motor. I also want to test some of my other aero bits I have sitting around...

Oh c'mon Keith, it's simple. Just block out a few weeks in North Carolina to rent the only full-scale rolling road windtunnel here in the US, test every possible configuration of rake, dive, and yaw on a few of the newest APR wings, hire a few Bosch engineers to do a bespoke proportional and speed-sensitive control system, then design a titanium stanchion with a built in pneumatic actuator for minimal aerodynamic interruption. There's no reason to run an electric pnuematic pump and reduce your system efficiency when you could simply develop a PTO drive on the diff that activates once it determines the downforce has been applied by strain gauges on your tophat mounts. To save weight, you could use your roll cage as a pressure vessel and act as the pneumatic plumbing itself.

Awesome. I was just talking to the guys a few days ago about rigging up something similar for our Lemons/Chump car using junkyard stuff. Then we decided we didn't have the skill to make it work and laughed it off.

Now.....hmm...

You want a huge amount of torque from an electric motor, cheap?

Get a starter motor for a bike. 500+ W at 500 RPM is several lbs*ft of torque. That'll pop a wing up and down VERY convincingly. Take off the Bendix and it'll be reversable (it'll work a lot better going one way than the other).

In reply to chaparral:

Not that simple. Starter motors are not designed for holding torque, and controlling static position on a brushed DC motor is, um, difficult. It's much harder to backdrive a worm gear like in the headlamp actuator.

In a car you can afford the weight and power draw of an air compressor, and pneumatics are an excellent way to transmit a lot of force and intermittent power. Bimba has everything you could possibly want. When in doubt, go too big.

Warren v wrote: In reply to chaparral: Not that simple. Starter motors are not designed for holding torque, and controlling static position on a brushed DC motor is, um, difficult. It's much harder to backdrive a worm gear like in the headlamp actuator.

Yep. Control will be mechanical (consisting of a linkage that goes over-center and then hits the limit shutoff switch).

I'm assuming that there's a good reason you're not following Porsche's tracks from 40+ years ago. [Flaps actuated by the suspension. Also, left and right independent to provide downforce on the inner rear tire?]

David

Holy cow guys, Keith doesn't have to reinvent the entire history of active aero here.

first I looked at this thread, wow, nicely done

will there be a kit

Well, the mounts I used as a base are part of a group buy at Flyin' Miata right now (http://flyinmiata.com/groupbuy/index.php). The headlight motors and wing are available on the used market. I can tell you where to get the pushrods and the SPDT relay.

So there's your kit. The hard part is actually doing it.

That is so cool. Well done!

I don't think Huayra-style independent left and right control is a great idea. It lets you do some nifty things like aero-assisted yaw control and aerodynamic anti-roll, but I don't think it's going to be as quick as just getting as much downforce as your engine power can afford when you're in the corners and cutting it on the straights. Maybe getting lots of drag under braking.

I still think there are better ways to do the air brakes than using the wing though, if you can get your drag and downforce at the same time that would be best.

Hmm, I just realized I still have the actuators for my RX7...

Just watched it again and I'm still impressed :)

In reply to GameboyRMH:

Hmm, pop up flap from the trunk lid that's independent from the wing and its mounts?

To add to the armchair quarterbackgineering, what about just the solenoid from a starter? Simple tension spring to provide resistance/ return

Keith, you keep shrinking my pants and my girlfriend is getting suspicious...

bluej wrote: In reply to GameboyRMH: Hmm, pop up flap from the trunk lid that's independent from the wing and its mounts?

I thought about that but anything under the rear wing would kill its downforce.

Maybe cut some metal from a scrap Miata to have fender over-covers that pop up?

Speaking of SCCA and active aero, while at the SCCA solo nationals recently, I got to talk to some of the guys from University of Texas - Arlington about their FSAE car they were there competing with. It had a DIY active aero setup with pretty slick execution that used input from a two axis accelerometer, two position solenoids, independent left and right side wing elements, microswitches with position feedback, and a DIY control board IIRC. Seemed pretty well thought out. Fun to watch as a spectator.

http://www.youtube.com/watch?v=7UUl6VN4bGY

Bryce

This is 57 varieties of awesome.