50cc pocket bikes as part donator?

[olaf-lampe]

Hi,
many of these crappy bikes can be bought for peanuts. Are there any useful parts for a non_frock e-bike like the 2-step gear-reduction?
I wanted to build an electric pocketbike for a long time, but then decided, range would be too low. Next idea is to make it electric and radio controlled but I have no idea how steering works on the usual RC-bikes?
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11455
Maybe I scan the rc forums for an idea
-Olaf

 

[Thud]

Those steer by having enough "Trail" built into the front end to make them self stabize.
The steering servo cants an angle on the stem to get it "out" of ballace (left or right) Speed & inertia are the determing factors of how tight the turn is made.
I hope that wasn't too confusing. I am weak writing descriptions lately. they do look like fun. There is some good race footage on youtube of the 8th(?) mayby 5th scale RC engine powered racing

 

[olaf-lampe]

I thought so Thud! They are driving 'handsfree' and by shifting the COG they turn left or right.
I'm not familiar with the term trail. Is it the angle/distance between rotation axle of the fork and the center of the wheel?
-Thx, Olaf

 

[Thud]

Here is a link to one of the better designer types I have found over the years.
http://www.tonyfoale.com/Articles/RakeEx/RakeEx.htm
lots of great tech info that covers a wide range of applications.

 

[liveforphysics]

The hobby city RC-bike, and many others as well, use a flywheel driven by a spider gear setup, kinda like a reverse-hubmotor arangement. The flywheel is a large diameter steel disk that is geared to spin as maybe 5x the rear wheel speed as the wheel turns. This lets it get good stabilization at low speeds and stay up. It will still fall if it's not moving of course, but it wants to right-itself almost instantly once it starts moving from the flywheel.

 

[olaf-lampe]

Ok, thanks Thud and Luke for the info. It seems a bit clearer now. There is a steel disk IN the rear wheel? Hobbycity mentioned a gyro, like in a heli, I guess.
I've seen some vid's on utube about r/c pocket bikes.
They all seem to steer only the fork itself with pooor results. Also I thought, where would I drive such a huge bike?
In the vid's they don't even try to accelerate and soon driving out of sight. I better go for a pocket quad and chase rabbits with it LOL.
I think a windscreen wiper motor would be a nice steering/brake servo? Only have to adapt a poti and use some power FETs on a common servo-pcb.

Anyway, there is an auction of a pocket bike located nearby. Is it of any use for donor parts?
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=280498119226&ssPageName=STRK:MEWAX:IT

-Olaf

 

[recumpence]

Actually, the best RC bikes have no gyro, flywheel, or any other self stabilizing setup. Also, most do not shift weight from side to side. Most decent RC bikes run the fork tripple-clamps reversed for that "Trail" that was mentioned before. To steer left, the steering servo puts very light pressure on the forks in the right hand direction. That light right hand push makes the bike lean left. Then as the bike leans left, the front end "Falls in" to the inside of the circle. This falling in swings the forks to the left and it turns in that direction. The more pressure on the forks in the right hand direction, the harder it will turn left.

They are alot of fun. I was puting brushless motors and carbon fiber frames on these things for some time before moving to E-bikes. It is cool to overpower them and see what they can do.

Matt