NXT DraXTer #1, a dragster for racing a 5 meter track in the shortest time possible.
About this creation
This is my first attempt at a dragster from a single NXT set.
For a private competition, the dragster is designed to drive 5 meters in the shortest time possible. Constraints include a standing start, carrying the NXT brick/battery box, and finishing as started in one piece.
This dragster features huge spoiler wings, a 1:9 gear train and a stiff front wheel suspension as required by the little clearance under the body. The gear train and drive wheel construction was optimised for having little friction.
The brick runs a NXT-G program that does a proper countdown aloud, then rotates the motor full power to travel 5 meters, and finally clocks its own time with millisecond resolution!
The top speed of this dragster is theoretically 170rpm*9*56*pi/60 which is about 4,5 m/s or over 16 km/hr. However, the track of 5 meters is way too short to develop such a speed, particularly in view of its mass of 622 grams, mostly due to the batteries.
The fastest real run was in 3661 milliseconds. This equals an average speed of 136 cm/s. Assuming a constant acceleration the finishing speed must have been about 10 km/hr.
If i take the brick off and run along with it, it races 5 meters in 2590 milliseconds, finishing with about 14 km/hr. If i have a dry run holding it in my hand, it "finishes" in 1440 milliseconds. My interpretation is that the mass and gear ratio are reasonably balanced for the 5 meter track.
I am thinking about how to improve: stronger batteries, lighter batteries (LiIon), less gears/larger wheels, add motors andsoon.
Let me know if you come up with a faster time/design.
Build instructions are available from a photobucket subalbum at: NXTDraXTer NumberOne, start with IMG_8045 at about 1/3 of the album and count backwards, sorry for the misordering.
Yes, i aimed at using a single NXT retail set only.
However, i guess relaxing to non-NXT opens up for eg Power Functions, like the ChainRider, reaching 2.7 seconds, see: http://www.mocpages.com/moc.php/55609.
So yes, go ahead and see how far you can push it!
Mind you that Techno Moves came up with a machine that does 5 meters from a standing start in 1673 milliseconds, clocked by a NXT with a laser and two mirrors...
See his page http://www.mocpages.com/moc.php/69921