172 replies to this topic

[Felix Mottram]

I dreamt about it last night!

Someone had the nerve to tell me that I was ending the cartwheels facing the wrong way so I had to go back to sqaure one and sort it all out again. Geez!

Bart

OK, I know that syndrome! The next level is, of course, to do it in team/grid.

Arkwright and Granville are terms that might not be generally familiar but refer to team moves that are not far away from synchronous cartwheels...

Felix

[Khal]

I dreamt about it last night!

Someone had the nerve to tell me that I was ending the cartwheels facing the wrong way so I had to go back to sqaure one and sort it all out again. Geez!

Bart

I know just what you mean. When I first got bicycle/pinwheel spins working, I was doing them in my sleep.

[bartman]

After yesterday I know when not to bother sorting this out. I spent half the time trying to make a kite fly reasonably well without jerking all over the place. The wind was so up/down/gusty that I had to continually swap kites/rods/knots to the point it was just frustrating. I've never snapped a rod but I sure thought it was going to happen yesterday.

In the few good moments (maybe a total of 10 in a 90 minute period) I was doing left to right nicely, but not right to left very well. The weak side is always right to left whether it be this or an inverted slide, etc.. I wish I could sort that out but even with continual practice on the weak side the problem persists.

The rest of the time I was slamming the kite into the ground as a 20 kph gust would grab it at just the wrong moment and yank it around.

Usually if we get evening wind it is considerably smoother than what comes during the day. I've been out in the evening where the wind is comparable to the beach and flying is just wonderful. Lately the evening wind is just as nighmarish as the day.

Bart

P.S. I agree with the comments here that the proper amount of brake doing this is most helpful. Too much forward just seems to set it up for problems. I don't think enough brake existed yesterday to deal with the hurricane. Even the Xtra-vent wanted to jerk itself all over the sky regardless of settings.

[SkyPuppet]

I'm still thinking the Traveling Bicycle is a move that is different from what I see as the Cartwheel/Tumble:
This video is awesome! And was posted by Polo: http://www.revkites....ones-and-a-rev/. Check at 1:25 to see what I'm calling a Traveling Bicycle. The speed horizontally is consistent, but the spin speed of the Polo is quite faster, which reminds me of looking at the spokes of a spinning wheel - it appears to be traveling horizontally faster than it actually might be. As my arms are in the "pumping" motion for the bicycle, I get this one done with little, timed pulls on one hand only, kind of like a (horizontal) single-pull spin and climb.

This video, uploaded by Madquad, shows some excellent flying: . Check at :40 to see a beautiful example of a move that, IMHO, should have a different name, i.e. Cartwheel/Tumble. The Rev looks more like a gymnast (or a Slinky) here, hand-springing end over end. This move requires fairly dramatic, timed pulls with both hands, and, well....... plenty of discussion above on how its performed.

I think these 2 moves need separate names!

Sorry if I'm beating a dead horse here.

[RevWizard]

Think of how you tumble on the ground, how a bicycle wheel rotates on the ground and how cartwheel rotates on the ground. They are all the same direction of rotation in relation to the direction they move on the ground.
Now think of Michael Jackson how he shuffled his feet in the moonwalk.

[bartman]

I'm still thinking the Traveling Bicycle is a move that is different from what I see as the Cartwheel/Tumble:
This video is awesome! And was posted by Polo: http://www.revkites....ones-and-a-rev/. Check at 1:25 to see what I'm calling a Traveling Bicycle. The speed horizontally is consistent, but the spin speed of the Polo is quite faster, which reminds me of looking at the spokes of a spinning wheel - it appears to be traveling horizontally faster than it actually might be. As my arms are in the "pumping" motion for the bicycle, I get this one done with little, timed pulls on one hand only, kind of like a (horizontal) single-pull spin and climb.

This video, uploaded by Madquad, shows some excellent flying: http://www.youtube.c...h?v=CKO0RpXoVZ0. Check at :40 to see a beautiful example of a move that, IMHO, should have a different name, i.e. Cartwheel/Tumble. The Rev looks more like a gymnast (or a Slinky) here, hand-springing end over end. This move requires fairly dramatic, timed pulls with both hands, and, well....... plenty of discussion above on how its performed.

I think these 2 moves need separate names!

Sorry if I'm beating a dead horse here.

To me both of these are examples of the travelling bicycle in form, but the second one, imo, spins too fast. It still looks great, but the first example is how I think it should look. Slower and more rolling in time with distance covered.

I am getting mine to look like the first example more and more. I still have some issues with speed of rotation vs. distance travelled and I still have cases where I rise or fall instead of staying nice and parallel to the ground (and in the first video I see this happens to him as well), but I have made vast improvements since last posting to this thread.

With all of the practice though I am still not really sure how I'm accomplishing it. My mind has yet to reconcile the physics of it!

Bart

[--Pete]

The kite should look as though it was painted on a transparent disk which is the diameter of the LE, and is rolling across the ground.

[RevWizard]

rolling across "and above" the ground

[--Pete]

Yes, the base line that the disk appears to be rolling upon could be any line from the ground on up. I suppose that it could even be at an angle or vertical, but I don't think I have ever seen it done that way.

BTW, this means that any point on the kite (in a properly done cartwheel) moves along a path called a cycloid . The tips of the LE move in true cycloids, while other points on the kite move in curtate cycloids.

[bartman]

Yes, the base line that the disk appears to be rolling upon could be any line from the ground on up. I suppose that it could even be at an angle or vertical, but I don't think I have ever seen it done that way.

BTW, this means that any point on the kite (in a properly done cartwheel) moves along a path called a cycloid . The tips of the LE move in true cycloids, while other points on the kite move in curtate cycloids.

I think using the logo as the axle of the wheel means that the LE tips will not make a true cycloid but pretty close. Aiming for that shape is the goal. Close doesn't count in this case because only one shape would be the proper look of the finished move. I disect my thinking on this exact same thing in my blog.

Bart

[RevWizard]

While doing the Super 16 team animations, I found the center point to be below the V in the trailing edge.
Take a sketch of a REV. Draw a rectangle around it, touching the outer points of the REV. Then draw a line from one corner to the opposite corner. Now, do the same with the remaining two corners. The crossing point would be the center.
http://revkites.com/...68476_thumb.png

Attached Thumbnails

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[Khal]

While doing the Super 16 team animations, I found the center point to be below the V in the trailing edge.
Take a sketch of a REV. Draw a rectangle around it, touching the outer points of the REV. Then draw a line from one corner to the opposite corner. Now, do the same with the remaining two corners. The crossing point would be the center.
http://revkites.com/...68476_thumb.png

But with so much of the mass and sail area concentrated near the leading edge, wouldn't it be more natural to use the center of gravity as the center of rotation? Or possibly the center of lift since it's not quite the same point? I know that a really skilled pilot can rotate the kite around any chosen center, but I'd expect it to be easier for us novices to rotate around some "natural" physical center. Of course it's possible that thinking that is the reason why I have trouble with these moves! Maybe controllability is better when NOT rotating around the natural center?

I know. I know. I'm over thinking it. It's hard to stop being an engineer and fly.

[Felix Mottram]

Yes, the base line that the disk appears to be rolling upon could be any line from the ground on up. I suppose that it could even be at an angle or vertical, but I don't think I have ever seen it done that way.

BTW, this means that any point on the kite (in a properly done cartwheel) moves along a path called a cycloid . The tips of the LE move in true cycloids, while other points on the kite move in curtate cycloids.

I seem to remember that Alan Nagao 'cheated' by making a circle of 'fiberglass' (I think) tubing and hanging the Rev in it. It was then rolled across the ground... 1990 or thereabouts I guess! <grins>

Felix

[Felix Mottram]

Yes, the base line that the disk appears to be rolling upon could be any line from the ground on up. I suppose that it could even be at an angle or vertical, but I don't think I have ever seen it done that way.

<snip>

I have certainly tried it on the diagonal...

We have been looking at 'rolling' the four person (or more) ball recently, well for some time actually. Now there is a challenge <grins>

Felix

[bartman]

While doing the Super 16 team animations, I found the center point to be below the V in the trailing edge.
Take a sketch of a REV. Draw a rectangle around it, touching the outer points of the REV. Then draw a line from one corner to the opposite corner. Now, do the same with the remaining two corners. The crossing point would be the center.
http://revkites.com/...68476_thumb.png

That being the centre means I am closer than what I thought for all my spins!

Bart

[RevWizard]

That being the centre means I am closer than what I thought for all my spins!

Bart

I think the true center is closer to where the center of the four lines at the point where they attach to the bridle.
I think even with my experience, I would have difficulty rotating on the center of the logo.

John

[bartman]

I think the true center is closer to where the center of the four lines at the point where they attach to the bridle.
I think even with my experience, I would have difficulty rotating on the center of the logo.

John

Of course this means I've been beating myself up when I can't get that rotation on the centre of the logo! I think the rotation point for me always has been closer to where you show it. It always seems to have naturally been lower even with repeated efforts to "clean it up" and pin it on the logo.

I can ease off thinking about this one now.

Bart

[SkyPuppet]

Hmmmm
I seem to be having good luck with practicing the Cartwheel or Traveling Bicycle by modifying how I practice the precision move, Bumps. This helped me to practice Cartwheel-ing to the left for sure, where normal right-handed style practice wasn't helping.

While flying Bumps, cut the arc down to where the radius is just the length of the LE, and practice removing the stops in between "bumps". At first, It feels like a series of basic reverse launches and wingtip pivots. Once the timing is improved and the stops are removed, it winds up feeling like Bazzer described it previously in this topic - like Clockwork turns with horizontal a movement.

[bartman]

A half circle reversed looks way harder than a cartwheel to me!!

Bart

[SkyPuppet]

Technically its a reverse half circle, but if you make the radius of the half circle the length of the LE, it becomes more of a reverse wingtip pivot in terms of how its performed. When I perform Bumps off the ground, really fast and in tight (small arcs) it becomes wingtip pivot, reverse wingtip pivot, wingtip pivot, reverse wingtip pivot, etc etc. For me anyways, this becomes a Cartwheel when i control the forward movement as the LE rotates vertical.