Re: active aero project
This is what I love about Lemons. Your car eats an engine per 150 laps? ACTIVE AERO!!!1!
- TheEngineer
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Re: active aero project
Judge Phil wrote:
This is what I love about Lemons. Your car eats an engine per 150 laps? ACTIVE AERO!!!1!
well clearly. What else would a team of mostly engineers do?
moving along with the design. out of boredem i made an animation of the startup sequence planned to find wing center. The motion pieces are super simplified, obviously, but the other parts are fairly close to final design.
http://www.youtube.com/watch?v=7Yy4H-AT … e=youtu.be
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Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice
- m610
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Re: active aero project
They weren't active, but they were wings, on the sides of this (rocket-powered) Opel. Something like this could give you down force and keep the car level in the turns.
Momentum is a terrible thing to waste.
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- racinrob
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Re: active aero project
TheEngineer wrote:
racinrob wrote:Chris,
Figure out how much downforce a 5' x 5' wing on the roof of a 93 Mustang generates. I was guessing about 200 pounds until I saw your previous post and your wing is approximately 1/3 the surface and already generating about 150 pounds.
I can scale my wing profile up to roughly those sizes, but unless I have the exact profile and angle of attack it's going to be a wildly inaccurate result. I'll try it anyway.
A super quick look using the foilsim app mentioned a few posts up gives me 301lbs downforce, and 165lbs drag. But just changing the angle of attack 4 dgrees changes that to 331lbs down and 200 drag. That's at 60mph BTW. At 80mph it's 537lbs down, and 294drag. remember that all these numbers are purely theoretical, and a huge number of real world factors will change them.
Go play with the foilsim app, is very user-friendly, and great for just getting an idea how different adjustments effect airfoils. when it first opens, make sure you change the size tab because it starts you off with a 5ft chord 20ft span wing. Flight is where you change your speed, and shape is where you tweak the airfoil shape.
edit: here's the link again
https://www.grc.nasa.gov/www/K-12/airplane/foil3.html
Thanks. That is close enough for me.
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"PA Posse" 29th out of 133 and Class C WINNER, Halloween Hooptiefest 2013
"PA Posse" 33rd out of 151 and 2nd in Class C, The Real Hoopties 2013
- TheEngineer
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Re: active aero project
V1 of the code is almost done. Now I'll need to start getting the final bits of the real hardware to play with.
made an amazing decision tonight. Covered the backside of the glass on my desk with painters tape. Now it's a whiteboard. Best thing i've ever done. When it's warmer outside i'll replace the tape with white paint to make it look better.
20+ Time Loser FutilityMotorsport
Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice
Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice
56 2014-02-26 08:05 PM (edited by jrbe 2014-02-26 08:07 PM)
Re: active aero project
Before you get too far you might want to consider an accelerometer. When the rear end gets loose and steering goes to 0 then the "wrong" way to steer into it the wing may go wonky unless you have a delay before the wing drops. If it's barely holding though and the wing drops you'll spin. Accelerometer is nice because you can pick how much wing you want for what g load. Yaw input could be very helpful too for wing decisions. I know it's a lot of extra stuff but imho is at least worth considering (if you didn't already..) I think I'd ditch steering angle for g and maybe yaw. Steering angle will be confusing I think unless the programming is very elaborate.
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- TheEngineer
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Re: active aero project
I'm about as beginner of a programmer as they come, so this is all a challenge. But you're making one very large assumption about this project. That the wing will actually do anything. I know I've got fancy screenshots of aero models, but i fully expect the wing to be useless and just a show piece.
Steering angle is an easier starting point for me to learn with. As i figure more and more of this out I can consider adding an accelerator. For now it's easy enough to just add delays to all conditions so that the wing stays in "brake" mode after I come off the brakes, or add steering input.
I do also plan on having three modes for the wing. Full active, Partially active, and off. Full active will do the full song and dance. Partially active will hold the wing at it's normal angle, and only accept a DRS style input to lower it on a straight when requested (purely for driver entertainment). Off just locks it in it's normal position constantly. So if full active proves to be messing with the car you can kill it.
20+ Time Loser FutilityMotorsport
Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice
Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice