Propeller or jet to push an in-line skater?

In article ,
John Doe wrote:
How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor and
wheel to push oneself along the ground? What sort of incline would
be achievable at say a skater weight of about 160 pounds? I think
the rolling resistance can be assumed to be zero or maybe the same
as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention' type
TV shows featured a guy with jet engines mounted on the tails of
his skis. No need for a chair lift, he'd just ski uphill.

So it has been done, just make sure your life insurance is paid up.

John
--
John Clear - http://www.clear-prop.org/

usenet jac.users.panix.com (John Clear) wrote:

John Doe jdoe usenetlove.invalid wrote:

How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor
and wheel to push oneself along the ground? What sort of
incline would be achievable at say a skater weight of about 160
pounds? I think the rolling resistance can be assumed to be
zero or maybe the same as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention'
type TV shows featured a guy with jet engines mounted on the
tails of his skis. No need for a chair lift, he'd just ski
uphill.

Inline skating is like a combination of different sports,
including skiing. One unique difference is that in-line skating
requires man-made terrain.

So it has been done, just make sure your life insurance is paid
up.

If you wear lots of protective gear and consider the risks, safety
should not be a concern. On TV, you see skaters and cyclists who
do not wear protective gear, apparently many people enjoy seeing
the accidents, but I just change the channel. Carelessly riding
a large displacement motorcycle years ago makes anything I do now
days pale in comparison. This

Still researching the issue, but by the lack of detailed comment,
I get the impression that propeller power is nowhere near
efficient as conventional motor and wheel on the ground
propulsion. That is the question.
--
























John
--
John Clear - jac panix.com http://www.clear-prop.org/

"John Doe" wrote in message
...
usenet jac.users.panix.com (John Clear) wrote:

John Doe jdoe usenetlove.invalid wrote:

How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor
and wheel to push oneself along the ground? What sort of
incline would be achievable at say a skater weight of about 160
pounds? I think the rolling resistance can be assumed to be
zero or maybe the same as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention'
type TV shows featured a guy with jet engines mounted on the
tails of his skis. No need for a chair lift, he'd just ski
uphill.

Inline skating is like a combination of different sports,
including skiing. One unique difference is that in-line skating
requires man-made terrain.

So it has been done, just make sure your life insurance is paid
up.

If you wear lots of protective gear and consider the risks, safety
should not be a concern. On TV, you see skaters and cyclists who
do not wear protective gear, apparently many people enjoy seeing
the accidents, but I just change the channel. Carelessly riding
a large displacement motorcycle years ago makes anything I do now
days pale in comparison. This

Still researching the issue, but by the lack of detailed comment,
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.

Keith

On 23/07/2010 09:01, Keith Willshaw wrote:


"John Doe" wrote in message
...
usenet jac.users.panix.com (John Clear) wrote:

John Doe jdoe usenetlove.invalid wrote:

How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor
and wheel to push oneself along the ground? What sort of
incline would be achievable at say a skater weight of about 160
pounds? I think the rolling resistance can be assumed to be
zero or maybe the same as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention'
type TV shows featured a guy with jet engines mounted on the
tails of his skis. No need for a chair lift, he'd just ski
uphill.

Inline skating is like a combination of different sports,
including skiing. One unique difference is that in-line skating
requires man-made terrain.

So it has been done, just make sure your life insurance is paid
up.

If you wear lots of protective gear and consider the risks, safety
should not be a concern. On TV, you see skaters and cyclists who
do not wear protective gear, apparently many people enjoy seeing
the accidents, but I just change the channel. Carelessly riding
a large displacement motorcycle years ago makes anything I do now
days pale in comparison. This

Still researching the issue, but by the lack of detailed comment,
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.

Keith

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

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.

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

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.
--


























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

(John Clear) wrote in
:

In article ,
John Doe wrote:
How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor and
wheel to push oneself along the ground? What sort of incline would
be achievable at say a skater weight of about 160 pounds? I think
the rolling resistance can be assumed to be zero or maybe the same
as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention' type
TV shows featured a guy with jet engines mounted on the tails of
his skis. No need for a chair lift, he'd just ski uphill.

So it has been done, just make sure your life insurance is paid up.

John

how did he -not- fall on his behind?
get on some skates,tie a rope to your ankles,and have someone tow you,and
see if you can stay upright.
You need the center of pressure to be in the center of your mass.

--
Jim Yanik
jyanik
at
localnet
dot com

Jim Yanik wrote:

(John Clear) wrote in
John Doe wrote:

How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor
and wheel to push oneself along the ground? What sort of
incline would be achievable at say a skater weight of about
160 pounds? I think the rolling resistance can be assumed to
be zero or maybe the same as a small aircraft.

Years ago (maybe late 1990s) one of those 'whacky invention'
type TV shows featured a guy with jet engines mounted on the
tails of his skis. No need for a chair lift, he'd just ski
uphill.

So it has been done, just make sure your life insurance is paid
up.

how did he -not- fall on his behind? get on some skates,tie a
rope to your ankles,and have someone tow you,and see if you can
stay upright. You need the center of pressure to be in the
center of your mass.

Ideally, Yes. Also, putting a motor on skates weighs it down and
destroys most of the quality of skating. However, I have put a
motor on my skates, powering the center two wheels on one skate,
and it worked very well propulsion wise. The problem was with the
weight and the motor being too close to the ground.

On Jul 21, 8:57*pm, John Doe wrote:
How far-fetched is the idea, to use a propeller or jet engine
(radio controlled type?) to push an in-line skater? How does
aircraft takeoff thrust compare to using a conventional motor and
wheel to push oneself along the ground? What sort of incline would
be achievable at say a skater weight of about 160 pounds? I think
the rolling resistance can be assumed to be zero or maybe the same
as a small aircraft.

Anybody know about Everglades/marsh air powered boats? Maybe I
should do a little research on that one.

One thing for sure, if there ever is such a thing as a jetpack, it
will very easily push an in-line skater before it will lift a
person off of the ground.

Thanks.

--
(Crossposted, please feel free to remove the other group)

One thing is for sure it can't be too high or low relative to center
of gravity.

"David E. Powell" David_Powell3006 msn.com wrote:

One thing is for sure it can't be too high or low relative to
center of gravity.

That may be less critical than you think. Propeller propulsion
would be the freest form since it would not depend on the ground,
the full benefit of skating depends on freedom of movement. Push
stick based propulsion (a bulky prototype is currently being used
here) is stable, even when being pushed from knee level. I get a
third wheel effect, and stroking with my legs is not required.
Pushing/stroking is a HUGE source of instability while inline
street skating.