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Old Jan 15, 2013, 03:57 AM
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I'm certainly not claiming to have invented anything here, but there is a critical difference between my ball race placement and kjells'. Kjell has his ball races on the outside of his ring without grooves which will double the radial load capacity of his setup and slightly increase the axial load. My races are on the top and bottom of my ring plate in deep grooves. Being on the top and bottom, the races will support huge axial loads, but balls will likely push out at high speeds or unforseen radial loading.

If a heli bearing were to be used I imagine two would be necessary because helicopters only support the weight of the machine as an axial load from one direction. One bearing would have to be inverted for our purposes.

Looking back at the conversation I think mike has understood at least part of this for a long time due to his helicopter experience and I'm only now catching on.
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Old Jan 15, 2013, 06:33 AM
Kjell Dahlberg
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The balls in my VWD is working like a combination of axial and radial bearings, without separator between the balls.
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Old Jan 15, 2013, 09:04 AM
Kjell Dahlberg
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Quote:
Originally Posted by Lil aus View Post
Kjell
Any idea what you would consider a good flap angle !
The way to find out the best flap angle is to compare the Power consumption/Thrust. At different flapping frequency.
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Old Jan 15, 2013, 12:44 PM
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Originally Posted by Lil aus View Post
Mike,
Have you tried using the CF rod as spindle material
No.. I was concerned that it might not be up to absorbing shock impact, but now you have mentioned it and i the more i think about it, its got to be worth a try... Thanks for that, i'll see what i can dig up and try it out in the next couple of days....

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My assembly is now using all printed parts (except the bearings & fastners) weight per assembly (less shaft) is 20 grams, of which 8 grams are attributed to the two bearings.
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Old Jan 15, 2013, 01:18 PM
Kjell Dahlberg
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Mike .
Your new FWD looks very professional. It will be very interesting to see the results from your testing. What kind of Wing design are you using?
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Old Jan 15, 2013, 01:48 PM
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Kjell.

Firstly let me say that i like to use references as datums for comparisons, so my plan has always been to build VWD as a LH size machine so that i can compare size 4 size etc.... Hence my requirements maybe slighly more than yours because i am looking for stronger mechanics to flap LH size, where i think (forgive me if i am wrong) you are aiming for PH size wings..

Which is why i jump between aluminium and printed parts, as my all up weight goal is again the same as the LH... and i can see my implementation is going to be a mix of both..

So from your recomendations and reading what little i could find about wing design for this application I thought i would start off with a standard size LH wing. Which i will modifiy to accept the twin spars (wing twist) and re-position the diagonal and wing tip C/F rods accordingly.

In preparation for this project I ordered a spare blank LH wing from SK (Thanks Sean.!) when i ordered my LH all of which arrived over Christmas.

So wing shape, material and wing area will be the same as a LH, but spar placing and arrangement will differ.

I have also got a prototype printed hinge assembly working for the wings that opens flat for the down flap, but hinges down 45' for the up stroke, but that's down the line, one step at a time...

That said. any input regarding wing design is gratfully accepted from anybody..

Mike..
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Old Jan 15, 2013, 05:13 PM
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Quote:
Originally Posted by Snetzka View Post
Kjell.

Firstly let me say that i like to use references as datums for comparisons, so my plan has always been to build VWD as a LH size machine so that i can compare size 4 size etc.... Hence my requirements maybe slighly more than yours because i am looking for stronger mechanics to flap LH size, where i think (forgive me if i am wrong) you are aiming for PH size wings..

Which is why i jump between aluminium and printed parts, as my all up weight goal is again the same as the LH... and i can see my implementation is going to be a mix of both..

So from your recomendations and reading what little i could find about wing design for this application I thought i would start off with a standard size LH wing. Which i will modifiy to accept the twin spars (wing twist) and re-position the diagonal and wing tip C/F rods accordingly.

In preparation for this project I ordered a spare blank LH wing from SK (Thanks Sean.!) when i ordered my LH all of which arrived over Christmas.

So wing shape, material and wing area will be the same as a LH, but spar placing and arrangement will differ.

I have also got a prototype printed hinge assembly working for the wings that opens flat for the down flap, but hinges down 45' for the up stroke, but that's down the line, one step at a time...

That said. any input regarding wing design is gratfully accepted from anybody..

Mike..
Kinkades wings will not work as it is in your application and most probably you will have at least to split them and few more modifications will be necessary . Ask Kjell about W.Mueler experience.He is the guy who first reproduce the W-drive and second who piloted W-drive powered ornithopter after Kjell ewer.Also read posts # 133 and especially #135 in your thread again.There is an important information.The author is the designer of one of the best performing ornithopters to the moment.
Sorry about the history lesson but it's good for you to know about all that things.
Success
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Old Jan 16, 2013, 02:18 PM
Kjell Dahlberg
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Mike .
Learn from Kazu-Kacu how to make a strong and light weight wings.
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Old Jan 17, 2013, 01:42 PM
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Mike, from a theoretical perspective your current geometry has the vwd moving the wing lever from its least advantaged point. You may be able to trade wing sweep for longer lasting hubs by using a common axle, rotating both vwds down 90 degrees and powering the wings with a spar that attaches 1/3 of the way down the wing.
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Old Jan 17, 2013, 02:08 PM
Kjell Dahlberg
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Quote:
Originally Posted by MattK_NZ View Post
Mike, from a theoretical perspective your current geometry has the vwd moving the wing lever from its least advantaged point. You may be able to trade wing sweep for longer lasting hubs by using a common axle, rotating both vwds down 90 degrees and powering the wings with a spar that attaches 1/3 of the way down the wing.
If you give us a drawing it will be easier to understand your theoretical point of view.
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Old Jan 17, 2013, 04:44 PM
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Quote:
Originally Posted by MattK_NZ View Post
Mike, from a theoretical perspective your current geometry has the vwd moving the wing lever from its least advantaged point. You may be able to trade wing sweep for longer lasting hubs by using a common axle, rotating both vwds down 90 degrees and powering the wings with a spar that attaches 1/3 of the way down the wing.
Hay Matt, i agree with you, it's taking all the load at that point. I did breifly look at the common axle idea back in Spetember when Kjell posted it as an idea (Post #34 in this thread.) and driving the common axle with a pulley (or gear) in between two Horizonally laid vwd's, but the adjusting mechanics (at that time) was taking up 20-30mm of space each and the whole thing was getting wider very quickly... and all i was doing was just moving the stress areas outboard...

But have to agree with Kjell, a simple sketch might be in order here to help my aged brain...
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Old Jan 19, 2013, 09:02 AM
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Chinese Wiggle Drive

Chinese Wiggle Drive:

Вращающиеся тарелки / Rotating plate / (旋转板) (4 min 13 sec)


Very interesting !
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Old Jan 19, 2013, 09:39 AM
Kjell Dahlberg
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Velko.
Where do they connect the wings?
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Old Jan 19, 2013, 01:20 PM
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Sorry, I have a one month old and a mother in law visiting. Most of my ideas don't work anyway, and I'm currently focused on getting ready for my 3d printer arriving in a few weeks. I'll be back when I can make parts.
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Old Jan 19, 2013, 02:26 PM
Kjell Dahlberg
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The VWD is an excellent tool for people that like to make experiments with wings and find out the best wing design.
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