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Old 09-13-2013, 11:34 AM   #21
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Exactly. The down position is shown. The rod is under pure compression. Of course, the wing is generating downforce so it's not trying to lift off at all. There is some torque load on the actuator in the up position, but I kept it to a minimum. How will the motors react to that? Well, that's why we test, isn't it?

Any "rub marks" are simply reflections, there are none anywhere. There are no parts rubbing against each other. The front pivot rides on some nylon bushings. As you can clearly see from the picture, the plastic bushings from the original headlight mechanism have been replaced with rod ends.
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Old 09-13-2013, 02:28 PM   #22
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Quote:
Originally Posted by fooger03 View Post
LOL WUT?

Picture is of the wing in the down position. There is no torque load on the actuator, and the rod sees only a compression force.
Tension

WTF happened to the crossed out line thing?

IMO it would be a lot better to toss a bolt in the middle of the wing wing mount and remove the front bolt. This will make it so the wing sees its main force in the center so it balances this way the actuator will see a lot less force acting on it like it is now. While in the process toss a proper hinge to make the joint stronger.
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Old 09-13-2013, 03:40 PM   #23
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How's the grip with that steep angle during braking? You think it would make drag to slow the car down (thus saving on brakes) as well, perhaps?
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Old 09-13-2013, 04:54 PM   #24
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I think that is it's main purpose. I assume the wing is stalled at that AOA. At best it is acting like a spoiler at that point.
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Old 09-14-2013, 10:23 AM   #25
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Very cool Keith. I lust for it. How does it feel under braking?

I wish we could use something like this in NASA-TT. I brainstormed some type of active aero like this, at least until NASA outlawed it last year. It would be huge on the fast courses for a TT3 car.
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Old 09-14-2013, 11:48 AM   #26
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Im glad someone is trying it, Good job Keith.

I was looking at doing a DRS system on a dual element wing. The second element only has to move 2" on the front edge.

I made these calculations on the high end of the scale 160 mph to see about how much force the actuator would have to handle. So at 160 mph if the DRS was active it would make 565 Lbs of downforce @ a 27.5 HP draw. In the max max AOA (or in normal cornering mode) on the second element it would produce 1650 Lbs of downforce @ a 192 HP draw.

Last edited by 1993ka24det; 09-14-2013 at 06:31 PM.
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Old 09-14-2013, 02:04 PM   #27
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Quote:
Originally Posted by 1993ka24det View Post
Im glad someone is trying it, Good job Keith.

I was looking at doing a DRS system on a dual element wing. The second element only has to move 2" on the front edge.

I made these calculations on the high end of the scale 160 mph to see about how much force the actuator would have to handle. So at 160 mph if the DRS was active it would make 565 Lbs @ a 27.5 HP draw. In the max max AOA on the second element it would produce 1650 Lbs @ a 192 HP draw.
Exactly, you can clearly see the problem with the current design.
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Old 09-14-2013, 04:36 PM   #28
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Can you guys tell me what track your hitting 160mph at in your miata? I would like to visit that track. I hit almost 140mph on the front straight at Texas World Speedway. One of a few "super speedway's" in the the US. Even in my buddy's Boss 302 mustang with the absolute best we could manage out of the last corner onto the banked front straight was 150mph.
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Old 09-14-2013, 06:27 PM   #29
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Can you guys tell me what track your hitting 160mph at in your miata? I would like to visit that track. I hit almost 140mph on the front straight at Texas World Speedway. One of a few "super speedway's" in the the US. Even in my buddy's Boss 302 mustang with the absolute best we could manage out of the last corner onto the banked front straight was 150mph.
It wasn't exactly for saying a Miata could reach 160 especially with 200 hp in drag, but it was for what the maximum the wing CFD was tested. I wanted to see the max weight the actuator would have to handle, even if it could or couldn't even reach 120.
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Old 09-15-2013, 01:43 PM   #30
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Quote:
Originally Posted by curly View Post
Id rather see a pressure sensor in the brake line so it only goes up during intense braking, rather than a delay timer for release. All the little brushes of the brake pedal during around town driving (as seen towards the end of the clip) would seem annoying.
I was thinking of adding a VSS component to the trigger logic (IE, don't change states if brake is depressed under XX MPH), but that is also a good idea.

I should have some Miata headlamp actuators around here somewhere, and will have a COT wing next week for the Exocet. This might be a fun excuse to build a cool little microcontroller that accepts inputs such as brake fluid pressure, VSS, maybe accel, and allows user definable logic to rotate the wing. Or for that matter, may be able to get it incorporated in MS3 code, which may be the excuse for a CAN based 3-axis accelerometer, something I've wanted to do for the past 2 years.

Thanks to Keith and Warren for the ideas.
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Old 09-15-2013, 06:00 PM   #31
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FTFY!

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Thanks to Keith and Warren and curly for the ideas.
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Old 09-15-2013, 06:13 PM   #32
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Quote:
Originally Posted by triple88a View Post
Tension

WTF happened to the crossed out line thing?

IMO it would be a lot better to toss a bolt in the middle of the wing wing mount and remove the front bolt. This will make it so the wing sees its main force in the center so it balances this way the actuator will see a lot less force acting on it like it is now. While in the process toss a proper hinge to make the joint stronger.
I agree with this. Proper placement of the pivot point will minimize load on the linkages involved. As a side effect slower and/or weaker and/or shorter travel mechanisms can be used to actuate the movement.
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Old 09-15-2013, 06:18 PM   #33
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FM duct?

Zing.
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Old 09-16-2013, 12:03 PM   #34
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I decided to do the initial proof of concept test with minimal modification of my wing. Thus no guesstimates as to where the center of balance needed to be on the wing, no extra holes in my wing, and it also allowed me to use my existing uprights as a base. As a bonus, it gives me a wider range of front mounting points to deal with things such as pushrods that weren't quite the same dimensions as described in the McMaster-Carr website It's not the perfect, ultimate implementation. But it's the best one we've seen so far.

Track test wing cam. Max speed was around 123 mph on this. The motors have no trouble lifting and holding the wing at that speed. I did set them up so they had maximum leverage for lifting the wing - they don't pull as hard on the return, but they have the load on the wing to help them.



Unfortunately, the Traqmate didn't record the session with the active wing and I have weird readings with what it did record - I was going -3358.19 mph at one point. Argh. So actual data will have to wait for a few weeks. But I can report that the car feels excellent under braking, very stable. Since the brake lights come on with even a small movement of the pedal, modulating the brakes doesn't cause the wing to spasm. The car didn't change behavior dramatically, it felt as if it had a brake upgrade and was less likely to lock up. Of course I didn't test to see what happened if I triggered the wing by braking in the middle of a high-speed corner because that's not clever anyhow.

Last edited by [email protected]; 09-16-2013 at 12:37 PM.
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Old 09-16-2013, 12:57 PM   #35
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Oh man, I am so happy to see this in action!
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Old 09-16-2013, 12:58 PM   #36
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I warned the starter and the corner workers that I'd be testing a moving rear wing, so please don't black-flag me for a mechanical. Big thumbs up from all the workers on the cooldown lap
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Old 09-16-2013, 01:52 PM   #37
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That is just awesome Keith! One more project for me to attempt when my Arduino gets here!
Any ideas for a cheap brake pressure sensor or pressure switch that has adjustable setpoint?
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Old 09-16-2013, 01:59 PM   #38
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You can get pressure switches from NAPA, that's how older cars used to trigger their brake lights. The Big Book Of Switches behind the counter will have pictures, thread type and (probably) trigger pressure information.
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Old 09-16-2013, 02:02 PM   #39
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Congrats Keith
Maybe the wing opened a new dimension to help you to 3358 mph. How to see some info next time.
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Old 09-16-2013, 02:03 PM   #40
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Quote:
Originally Posted by 1993ka24det View Post
Congrats Keith
Maybe the wing opened a new dimension to help you to 3358 mph. How to see some info next time.
well it was -3358 mph, so he must have gone through a worm hole.
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