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[Jimbo]

About 14 months ago I talked to Steve about a kite for an online workshop here. I ended up in a position where I couldnt move forward with my ideas, but now I'm back on track I think

This is the basic idea I had for the project, a mini crown kite.



Its an 8 sided version rather than 12, which gets big, and kind of pricey. This design is based on 30 of the RET40 spars and has an outside diameter of about 74 inches. It uses 6 yards of cloth and about 8 yards of 1.5 inch slit Dacron.

Based on Steve's current prices (which haven't really changed much ) the kit would run about $175 dollars for everything (including the fittings)

I'll be building one in the near future, for testing.

Here are a few more pictures of the model.







Comments welcome

Jimbo-

[azkabanknight]

Would the "kits" have all the spars and fittings or just the fittings. I feel like we have the next workshop in the making. I would love to do a project like this, and I have a design already I just need to sell a whole bunch of cookies to raise the money.
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We are.... Penn State... that reminds me, I need a Penn State kite.

http://community.webshots.com/user/deborah9763

[Jimbo]

I dont know how Steve works out his kits, or prices them, but the price I showed above is for 6 yards of cloth, (seconds, .75 oz.) 30 of the RET40 spars. (6 cut to 10 inch pieces for the 16 vertical spars, the rest cut in half for the remaining 48 pieces that are 16.25 inches) 36 fittings from me, and seven yards of slit dacron.

I probably should have talked to Steve first, lol. But I always do things bassackwards...

This would be an "after new year" workshop, probably mid to late Jan.

Jimbo-

[DarrylW]

I like it, but I do have a concern about the frame.

In the other crowns you made, you had an outer ring of framing. That outer ring prevented a lot of twisting on the inner fittings. But this design doesn't have that. So the inner fittings are doing all the work to keep the kites shape instead of relying on the inherent stability of the triangular structure.

I really shouldn't try to explain this when I'm hopped up on cold medicine, but I'll try anyway.

Flatten this down to a 2D frame for simplicity. Take two of the triangle sections, and think of the fitting that joins them together as a hinge. If you flex the two triangle sections around, that hinge will move. But if you connect a bar across the points of the two triangle, it will prevent the hinge from moving, and become a very strong, stable structure. This is how truss bridges work.

In this case, the purple fabric partially acts like that extra bar, but I'm not sure by how much. On the scale your talking about, I really don't know if this will be an issue or not, but I wouldn't expect it to have a very high wind range before it collapses.

Hope that all made sense. If not, just write it off as the ramblings a drugged up guy with the flu.

All that said, I'd love to make one of these.

Darryl
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If I knew what I was saying, I probably wouldn't have said it.

[Jimbo]

Too much cold meds I'd say

The other crown kites are the same design as this one. they didnt have an outer ring of spars either.

The only difference here is the number of sides, and the fact that I'm using a shorter spar between the top and bottom ring.



This picture shows the typical 12 sided crown frame.

But you are right that it doesnt take full advantage of triangulation.

Jimbo-

[Pumpkin]

I thnk it may be the flu Darryl

I'm looking at a series of connected wedges tensioned by the sails..... seems fine to me

Jimbo..... whats stopping the upper and lower pulling apart

and yes....looks like another online project
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Pete
Where did you say the string goes?

[Jimbo]

I epoxy my fittings to the vertical spars. Others use lines tied between the fittings. I couldnt see a reason to add all that labor to the assembly time.

The new fittings will have the webs like Cirque added to his, and will use a new design for assembly.

Jimbo-

[kitepassion]

Hi Jimbo,
I made this 8 sided crown about 10 years ago. It was fun to build it but its a bit disapointing flying it.
Its not as stable as the 12 sided crown. I think it does need more vertical sails. A 12 sided crown has 6 of these sails and the 8 sided crown only has 2, Thatswhy its isn't so stable, I think.
I made 2 sail extra and they are atached to the rear end in the kite. They help but there position isn't perfect. Can you help me finding a better solution to this problem?

greetings
Jan


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www.kitepassion.nl

[Fore Check]

Crowns, and Fleds, and Boxes... OH MY!!

This is great!

I have a half-theory - with the summer flying season all but gone, people are starting to hunker down to spend some quality time with their sewing machines. This little mini-burst of projects is too cool!
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Simon

Discovering Something that Doesn't Exist...

Radix Lecti Rex

[Jimbo]

Jan,

I'd try changing the bridle location. Go to the outer ring, or try using the top 4 fittings on the inner ring. As in two short "V" pieces then attach your long bridle to those. The object is to get above or in front of the keel or rudder panels more.

Jimbo-