The Wind Powered Sail-less Boat

I don't understand Rick why would they need a fan on the treadmill experiments as they are anyway totally irrelevant to the dilemma at hand...

Also - your cart example of having the board as a sliding non-exhaustible force that you could extract more speed from that it has. What was the relevance in the first place? Its not like wind is made out of plywood...

 

First - I am sorry but I cannot quit.

3dyachts suggests that mutiplying power with time would NOT be energy. It very much is so. kW (kilowatt) is unit of power kWh (kilowatthour) is unit of energy - an can be expressed in joules if so wanted.

I am rusty with my physics as I do not need it these days too often.

F=m*a
(m=mass [kg], a=acceleration [m/(s*s)])

Kinetic energy is
E=(1/2)* (m * v * v)

(m=mass [kg], v=velocity [m/s])


it really does seem that joakim's formulas have no mistakes but your do.

I am still waiting a real explanation why it is possible to reach faster than downwind speeds (in actual travel) for an iceracer but not an apparatus of my video.



http://www.youtube.com/watch?v=IMEerIkOVZ0

 

try and let it go
it was a good joke on me
and im ok with it
whats life if we cant laugh at ourselves every once in a while
although
I do kinda miss beating the crap out of there arguments
it was so full of holes I was loving it
( going to have to do better than that kids )

the ice racers are actually dam efficient
they move tangential to the wind such that they realize an apparent wind at true wind speed
if you notice they have only two moving bits
the mast and the steering blade
any motion in the frame is directly subtracted from the forward motion of the vehicle so suspension is limited as much as possible
even the sail on the speedsters are solid vertical wings
the more rigged the better
gears would only slow it down
no matter how you arrange em
its back to basic physics for the fromula to explain it
which I dont remember off the top of my head
but look at the formula class cars
stiffest suspension they can carry
tight steering

dont get stuck on math games
its they theory that has to jive before any numbers need be crunched
I would never have admitted theoretical physics to these guys but that they had gotten stuck on a simple theory problem
not a math problem
or at least I thought they had
B

 

Yes, sorry Kerosene, there was mistake in my post too! (late at night)
Kinetic energy needs a mass somewhere!
Acceleration does not. OK.
a.s.o...

Now, just like others, I am tired of this discussion which, actually, proved to be a not so funny joke due to some reactions (...) a bit difficult to understand.

Still, if you don't see how an ice-boat - or a windsurf board - goes so easily so fast: take a piece of soap, and squeeze it between your two hands, or better between two flat polished panes, nearly parallel, of whatever that is: see how fast it escapes!!!

One of your hands (or of the panes) is the wind, the other one are the skates (with a firm lateral grip in the ice) or the fin of the board, fighting against leeway.

You will see that the more your two panes are parallel, you will need less movement of one pane toward the other to get the soap escaping fast, and the more angle they have they will have to move closer to each other to make the soap escape slower and slower.

Think it out, but sorry: I am just too busy (and now bored by it) to continue this discussion.

 

dont let a few poor sports get to you 3D
it was kinda funny in that dry English humor way
a few people
probably out of the loop
just got a little excited when they didnt understand the drivel that was intended to confuse and the people trying to unconfuse the drivel
I thought it kinda brought out the best in some
and the worst in a few others

Im just surprised no one actually bought me beer
I was right on target the hole way
I say they owe me a pint for being a good sport
and another for seeing the energy deficiency in there efforts from the word go
but no worries
there's a few nitwits in every pile
and after all
this is a big pile
B

 

the "hole" way!!!???!

Now, yep: you owe me a double, you!

 

oh Im sure thats not the only thing I spelled wrong mate
its kinda my trademark

I hadnt really thought about DDWFTTW till some yoyo suggested it



and it was down hill from there
I didnt guess that they had a battery in that thing
but I did suggest that it was a fake
I also suggested that it was a simple matter of adding up the energies or frictions cant remember which
on both the tread mill trick and the gears thing to show it doesnt work
and I kicked there buts on there considerations of the physics involved
besides

at this point most of them are to embarrassed to show there smiling faces
either that or they are still rolling on the ground laughing

so I gotta wonder how many of em were in on it and how many were serious
I think they had a lot of people believing
there were thousands of reads on that post

it was fun
rubbing there noses in the physics
its been fun knowing it was all just a gag
and yerp
I think I was the only one who from the go consistently said
wont work guys
thats a few rounds my way if you ask me
no flies here mate

on a side note
I was over on the hydropter thread and noticed they were bickering about the kiting kids kicking the pants off the +50 record
and how they wont recognize them as the speed holders
funny
guy spends a hundred million on a boat to hit +50
and some stoner with a surf board and a kite nails it spending what
a few hundred
now that's funny
I suggested a head to head race
didnt go over very well
ya think

I want to see it
B

 

Such strong denials seems to admit to some susceptibility and self defence at taking some of the bait....

 

oh Im guilty of that
as I said
I hadnt considered it before
so I had to think it through no doubt
but come on now
I pegged it
its not so hard to admit
you can fool some of the people some of the time
but

and it was dam funny guys
thanks for the laughs

 

now If you will excuse me for a minute
Ive got to go find the kite boys and see if I can get em to challenge the hydropter guys
seems there is a little difference of opinion as to who holds the speed record
and frankly Ild love to see sea biscuit all over again

what a great name for the kite boarder to take on
yow

god I hope I can make this happen
what if we were to start a race fund
a few bucks from us all
as prize money
winner take all

does that violate site rules in any way
to suggest a race and start a prize fund
some one clue me in
cause Im not trying to violate any rules here
I just want a nice sportsman like race between David and Goliath
would be the event of the century
world news stuff
Im calling CNN
maybe they can pull this off

 

Yeah that sure was funny, i'm still laughing now. I guess there's always someone who's kind enough to call an end to a prank.

Sorry if i was a bit harsh at times, had to sound authentic you know......

We all knew it couldn't go on indefinitely, especially when E=mc2 was mentioned....

 

to funny
was a great time

 

**** you, Rick! (And Joakim, Tcubed and others)
I thought (and very surprised, indeed!) you were seriously supporting the damn DDWFTTW thing!

All the best.

 

More rotor musings. I assume true wind is affected by a spinning rotor's downwash before it becomes part of blades' apparent wind. I have a rather messy image of two colliding air masses, in a neater abstraction, opposing downwash would reduce upwash resulting in a negative (ground?) effect. The use of high speed twistedly bladed rotors with highest opposing downwash is dominant, but still not close to Betz limit. Is the problem in the wake, or might it be up front.

 

And we were. Love to here your current opinion.

Joakim