Giles Ayling giles tvp.ltd.uk wrote:

Keith Willshaw wrote:
"John Doe" wrote in message

....

I get the impression that propeller power is nowhere near
efficient as conventional motor and wheel on the ground
propulsion. That is the question.

No that is the answer.

Jet / Propellor / rubber band. It doesnt mallet what the power
supply is.

Are you using speech recognition? Or were you drunk?
Just curious.

Work out where the center of thrust/pull is - Probably if on a
skater approx 1.2metres up.

When the skater hit a bump to large for the front to quickly
rise over, the skater kisses the ground.

Skating is extremely flexible. One way to cope is to step over the
obstacle. Another way is by keeping your weight on your rear
wheels. And yet another way to cope with larger obstacles is
called "scissoring". And of course you can do stuff in
combination. If none of the above works, when you hit a bump that
radically slows one skate, you can quickly put all of your weight
on the other skate and simultaneously steer inwards with that good
skate to maintain your balance. You learn to do that stuff without
thinking.

But, coincidentally, large unexpected obstacles is exactly why I
made big front wheel skates, a 140 mm front wheel with 80 mm
trailing wheels. Love them and use them for rough street skating
regularly.

http://www.flickr.com/photos/27532210@N04/3056505603/
http://www.flickr.com/photos/27532210 N04/3056505603/




By the way... If anyone here (young enough to run or at least to
remember doing fun things) has never heard of "powered
paragliding", check it out! It is (lighter than) ultra light
powered flight. Amazing stuff IMO. Dozens of videos on YouTube.
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Think water skiing - It is a challenge to get up o the skiis, and then
the second you relax, and let the ski dig it, you are in the water