pic: Twin Fan Powered Vex Prototype#2

[gblake]

Originally Posted by amos229

i would position a servo on each wheel and then just rub one wheel or the other with a bar connected to a servo. hit both wheels to stop.

Steering & Braking Options (some already discussed)

• Two Hooks, one on each side. A servo on each can drag the on the ground to steer. Put both down to slow down or stop like a carrier landing.

• Two bars, one on each side. A servo on each bar can drag that bar on a rear wheel to slow that wheel.

• Get control over the fan speeds.

• Mount the fans on rotating platforms aimed by geared servos. Point the fans toward opposite sides to stop. Point them at the same off-axis point to steer.

• Stop (once) by deploying a parachute that is attached to the car and catches all the wind from the fans.

• Turn (and slow/stop) by dropping raising baffle plates behind the fans. To stop have the plates block all thrust coming out of the fans (leave a gap between the plates and the fan.

• Turn by putting a rudder (on the nose or) aft of the fans. Aft is better.

• Stop by lifting the nose wheel and letting a nose mounted skid plate create enough friction to slow you to a crawl.

• Turn by making an "active" chassis that uses a servo to slightly alter the rear wheel alignments and makes the robot turn.

• Stop by running into a pillowcase or net (or high grass).

• Stop by running your power through a switch that only remains closed if you have a command from your remote telling a servo to keep it closed. Good for safety...

[edit]

• My wife Jodie came up with this one - Raise and lower air-dams (sort-of like the ailerons on a wing) to create enough drag to turn it, instead of using a rudder.

• Instead of popping a chute; for a one-time stop, you could drop a grappling hook or anchor.

I still like the idea of plates that open/close over the back of the fans to let thrust out and/or point it. It will have sort-of a jet engine look to it; can be controlled by chains and sprockets from the middle of the machine; and if the default is to block the thrust, they will give you both a smoothly controlled start-up and a failsafe mode (I think you can rig this using just the default code).
[/edit]

Also - Put some shielding (strong screening won't hurt airflow but will keep fingers and other debris out) on the front and back of those fans, and some padding on the leading edges of this missile. Do it before someone gets hurt....

Blake