How would you make an airbrake for a car that is activated by the brake light signal ?

[freebeard]

I don't want to drill into the car,

https://external-content.duckduckgo.com/iu/?....&ipo=images

This would pull the dents. Similarly you could weld machine screws on instead of drilling.

[2015LXFIT]

Originally Posted by Cd

Thanks everyone for the replies.
Lots of great ideas, but I really wanted to go cheap and simple on this one.
I spoke with a guy at the hobby store. He liked the idea, but said that it would strip the gears when the flap would go down ( air and gravity force ) if I were to use a large R/C servo.
I may still persue the idea in the future. Just to get an idea of how it all might work, I'm thinking of just using a cable and doing it by hand.
This of coarse would just be to test what kind of force is needed to raise the flap.
I'm guessing a considerable amount, since a large plate sized flap moving up into 80 mph air is going to have quite a bit of force.
I want to have it be automated using the electrical signal, since doing it by hand and applying normal brakes would be very cumbersome and dangerous.

Did he specify if this was with metal or plastic gearing? I'm building one out at the moment, looking at the 54kG ones on Amazon with metal gears. Thanks.

[Piotrsko]

the metal gears won't make a difference until the servo starts getting rated above 200lb ft, then they pretty much come that way.
hobby store won't have powerful, you need to search online for actuators or linear drives.
The sailboat people have sheet winches for one man sailing

Might want to think of piston actuators

[Cd]

This is on the 'back burner' as far as projects go.
Was just planning for the future.
Thsnks for the tips guys !

[j-c-c]

Me personally, I would actuate with compressed air against a spring return to the low drag position., and also have a latching manual override for continuous braking, like for downhill runs. One advantage for air would be quick actuation, and an adjustable measured slow release as desired.