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PostPosted: May 24, 2016, 5:43 pm 
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A bit more complicated.

Speed switch for a 0 aoa down the straight away
Adjustable 3 position switch for a standard setting for 0-3deg aoa
Pressure switch to control as an air brake during hard breaking.

I think I have the programming down using my servo set up and arduino... just need an actuator now

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PostPosted: May 24, 2016, 8:00 pm 
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Stupid ideas beow in red.

mjalaly wrote:
A bit more complicated.

Speed switch for a 0 aoa down the straight away =TPS position. ~25% & >300ms= O degrees
Adjustable 3 position switch for a standard setting for 0-3deg aoa
Pressure switch to control as an air brake during hard breaking. =G sensor or brake pedal position switch

I think I have the programming down using my servo set up and arduino... just need an actuator now


Or maybe just a single vacuum sensor. high vac = brake (full angle) . Low vac = throttle (0 degrees)
Not sure why you would want variable attack angle. But then I don't play in that arena.

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PostPosted: May 25, 2016, 10:02 am 
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yeah those arent bad ideas. I also like the 3rd master cylinder idea too (i already have separate ones for the front and rear brakes).

I am thinking that having a neutral setting of 1°, 2°, or 3° that could be set in the cockpit would be ideal. then the wing could move up for breaking and to 0° down the straight... thoughts?

i was thinking something like this for an actuator but its a bit pricey.
https://www.pololu.com/product/2319

this one looks like it uses push cables
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PostPosted: May 25, 2016, 11:03 am 
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this is the wing i have i think (could be the gt 300) but if you look at the data, it has 343lbs of down force at 80mph and an AOA of 0. If its the 300 it has 672!
http://aprperformance.com/racing-produc ... ble-wings/

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PostPosted: May 25, 2016, 11:33 am 
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The system mechanical ratio would determine the amount of force the actuator need to be. 12VD Linear actuators can be had on eBay for <1/3 that cost. You would, of course, need to choose on that meets your needs. I'm not sure why you would need 3 positions, one neutral, one braking and one for maximum downforce. I can see only 2 positions necessary I think which would make it easier. But Like I said, I don't dwell in these circles. For the least expensive version of linear actuators, look at the junkyard for electric seat adjusters. Or here for $15 : http://www.surpluscenter.com/Electrical ... 1762-R.axd

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PostPosted: May 25, 2016, 2:08 pm 
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mjalaly wrote:
this is the wing i have i think (could be the gt 300) but if you look at the data, it has 343lbs of down force at 80mph and an AOA of 0. If its the 300 it has 672!
http://aprperformance.com/racing-produc ... ble-wings/

Assuming perfectly laminar airflow which is virtually never true - unless that's measured on the car.

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PostPosted: May 25, 2016, 2:13 pm 
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rx7locost wrote:
The system mechanical ratio would determine the amount of force the actuator need to be. 12VD Linear actuators can be had on eBay for <1/3 that cost. You would, of course, need to choose on that meets your needs. I'm not sure why you would need 3 positions, one neutral, one braking and one for maximum downforce. I can see only 2 positions necessary I think which would make it easier. But Like I said, I don't dwell in these circles. For the least expensive version of linear actuators, look at the junkyard for electric seat adjusters. Or here for $15 : http://www.surpluscenter.com/Electrical ... 1762-R.axd


yes but i am trying to avoid any mechanical linkages and just do something inline. And yes 3 positions as you said but having the Max down force selectable/adjustable would be best. For example, you would want more or less max down force on a circuit vs autox or from circuit to circuit.

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PostPosted: May 25, 2016, 3:13 pm 
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For example, you would want more or less max down force on a circuit vs autox or from circuit to circuit.


Maybe I'm not up to date, but moveable aero used to be banned, so you won't be able to run with anyone with this setup.

I would be concerned with the effective movement of downforce on the tires. How to you balance the car for braking and cornering with changing downforce? Your car has a lot of drag to begin with, so worrying about induced drag seems extra. I don't think the drag is a bad thing, do you really need to drive over 140 MPH?

How about a much larger wing over the cockpit like a dirt oval track car? You could make an adjustable flap for the back of it and servo that if you insist... At least your balance could stay more even with speed change.

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PostPosted: May 25, 2016, 3:33 pm 
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horizenjob wrote:
Maybe I'm not up to date, but moveable aero used to be banned, so you won't be able to run with anyone with this setup.

oh yeah its pretty banned for most races, autox too i think. Its just an engineering challenge thing i want to work on.

horizenjob wrote:
I would be concerned with the effective movement of downforce on the tires. How to you balance the car for braking and cornering with changing downforce? Your car has a lot of drag to begin with, so worrying about induced drag seems extra. I don't think the drag is a bad thing, do you really need to drive over 140 MPH?

the downforce wouldn't change except for straight line and when the air brake function is applied otherwise it will be at a pre determined/selectable setting. Since the car has an adjustable brake balance bar, i should be able to get it to work right when the rear wing is working as an air brake. Creating oversteer is the issue. The car needs aero for turns and to reduce the struggle at high speeds. However, a wing might be over kill considering that Atoms have issues with keeping their rear tires planed but my car does not for some reason. My car also has more power than the atoms so this is a bit confusing. Either my design is way better or they are driving their cars way harder!

horizenjob wrote:
How about a much larger wing over the cockpit like a dirt oval track car? You could make an adjustable flap for the back of it and servo that if you insist... At least your balance could stay more even with speed change.


it has to look decent too!

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Last edited by mjalaly on May 27, 2016, 9:19 am, edited 1 time in total.

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PostPosted: May 26, 2016, 8:41 pm 
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How about a much larger wing over the cockpit like a dirt oval track car?


I'e wondered why more people haven't done just this. It worked very well for John Meyers:

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