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Hi everyone! 

This has been one of those projects that I thought was going to be much easier than it ended up being, the benefit of that is that I know much more than when I started. 

SPOILER ALERT: WATCH THE VIDEO BEFORE CONTINUING READING.

1st thing learned: Battery voltage is not directly proportional to thrust gained. 6S batteries produce much more than double the thrust than 3S batteries (on the same setup).

2nd thing learned: Props have to be mounted taking into account flow direction. In this episode I used quad props to push instead of pull without flipping the props at first, and that caused a 66% drop on efficiency and a 800% increase on noise produced. As a  corollary, props have a slight taper that fits perfectly on the motor shaft so flipping the props requires a bit of extra force and worsens the balance of the props a bit. 

3rd thing learned: Flat, unobstructed ceilings that can be reached with a ladder in a public place without a road below are a scarce resource. I'll add testing location to the checklist for future projects. 

I hope that you liked the project, please leave your thoughts down below.

Thanks!!!

Files

RC CAR DRIVING ON THE CEILING

Comments

Bruce Lunde

I don’t know how you come up with these ideas, but you help me by saying “why not try that?” I love it!

Ted Gaunt

Looks like fun. Would like to see you take it further, please don't stop on this - as that would just be a tease. There's going to be an optimal distance from the fan to the wall. I think you can control that by adding some out-board wheels or offsets to the outside edge of the fans. I noticed from the video that one fan will tip down the suspension first, and especially under higher throttle,. When this happens, (leaning hard left or right to touch fan to wall), you loose equilibrium, and thrust on the other side, and disrupts the whole thing. A small "ball caster" or similar would hopefully not introduce too much friction for forward driving, while it would do wonders for keeping the thrust balanced and accurate. (Kind of like a type of "wheelie bar") Take a moment to add a tether to the car, perhaps with a small inline spring. That way when it falls off the wall or ceiling, it will gently swing from the tether and be generally less of a nail biter. The video segment showing it try to transition from floor to wall was really exciting. Minus the breakage. In the slow motion video, you can see that it failed to adhere because the left fan wasn't turning. Seems like a fun problem to solve, and would really add another dimension, if you could drive from floor to wall!!! You're so close! How about with a 45 ramp? What about redesigning the center of the car? Then you can make the fans very close to the centerline, and have a custom chasis. This would allow you to change the wheelbase length, which might help too.