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Old Jan 12, 2013, 05:45 AM
Kjell Dahlberg
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The Wiggle movement is a Fan-Flapping movement with the same flap angle and Fan angle. (The active wing twist). Adding a flexible part in the wing, the passive wing twist is helping to produce more thrust.
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Old Jan 12, 2013, 03:04 PM
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"The Wiggle movement is the best of the mechanical ways to move the wings for flight. "

I'm not convinced of this yet. I grew up swimming laps in pools and even though water is a much thicker fluid than air I believe the mechanics should be similar. In a freestyle stroke, which is the fastest, the goal is to maximize drag and maximize the length of the power stroke with your arms as you pull them through the water and minimize drag on the return stroke by lifting them out of the water. In this way freestyle takes advantage of the differences between the viscosity of air and water.

From watching slow motion videos of birds taking off I immediately see asymmetric pitch angle, surface area, stroke length, and speed when comparing the up and down strokes of the wings. This reminds me of an underwater breast stroke pattern of movement.

I believe that in the return/upstroke birds are rotating their wings so as not to resist the just generated down draft of air and pulling their wings back so as to make the upstroke within the partial vacuum they have created.

What I'm trying to say is that the reciprocating motion that all these drives create is only one motion out of many motion patterns superimposed on each other in winged flight. This basic reciprocating motion without mid- stroke pitch angle adjustment matches tail fin motion of fish but not birds.
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Old Jan 12, 2013, 06:34 PM
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MattK-NZ

Good analogies. Upstrokes can be a real drag!
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Old Jan 12, 2013, 07:17 PM
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Hi Matt

If a give system was introduced to the wing spar it could take the symmetry out
by means of a lead / lag effect !
What i mean by give is the ability to flex, and it should flex more on the upstroke and be rigid on the down stroke... a snap back effect which with the ability to tune could track back through this partial vacuum, maybe ?
Craig
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Old Jan 12, 2013, 08:23 PM
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Originally Posted by Lil aus View Post
Hi Matt

If a give system was introduced to the wing spar it could take the symmetry out
by means of a lead / lag effect !
What i mean by give is the ability to flex, and it should flex more on the upstroke and be rigid on the down stroke... a snap back effect which with the ability to tune could track back through this partial vacuum, maybe ?
Craig
Thanks Craig, that seems well worth a try, your way sounds like it could be very passive and lightweight. I have four brainstormy ideas:

1) Some kind of cam system at the shoulder guiding the wing pitch of each wing individually through its stroke path, perhaps spring loaded, but also perhaps a cable pulled around an eliptical cam pulley.
2) some kind of servo controlled heli-style gimble/swashplate pitch control either for each wing or for both wings at the same time.
3) Passive articulation of the wing designed so that the wing locks on the down-stroke and collapses on the up stroke.
4) Active articulation of the wing using something like a bicycle brake cable.
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Old Jan 13, 2013, 04:35 AM
Kjell Dahlberg
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It is very easy to make complicated flapping mechanisms. I prefer to simplify the systems and using less moving parts.
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Old Jan 13, 2013, 12:52 PM
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You've done a good job getting things simple, Kjell. I wonder if you could test something on your spinning test equipment? I'm curious to see a graph of the current drawn by the motor throughout the flapping cycle. Knowing that, a cam could be designed to flatten the curve and reduce system stresses.

As for my model, it doesn't work as is. My ball and socket idea allowed the ball to spin in the socket and prevented rotary motion from getting to the swashplate. It seems pretty stupid now. I can post the broken model if you really want to see it.
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Old Jan 13, 2013, 02:46 PM
Kjell Dahlberg
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I like to see a picture or a drawing of your system.
In my spinning test bench I can measure the following things.
Power consumption. Flying speed. Thrust. Flapping frequency. Pressure on wing sides. Accelerations.
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Old Jan 13, 2013, 04:26 PM
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Not all swashplates use thrust bearings like you have depicted there Kjell
Every heli swash plate ive worked on have used radial...the big ones double row deep groove angle contact and +6k ea.
the only type swash plate i have see with thrust bearings are hyd pumps,
I see another possible solution here.... it only requires 1 swash plate bearing, but it requires 2 shaft bearings, the spindle needs to be rigid...
Hope this isn't seen as riding high and I'm contradicting myself, but I can see 2 swash plates in that picture
1 has a dog leg and the other a pivoting hub....they both swash. Get a coin and spin it on a table, as it slows it will fall into an accelerating decay swash motion. Discovered / invented by Boris 1910.

Pic attached is an old heli swash plate bearing, its a impossible to get them small as we require, single row radial bearing will easily stand up to the job !
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Last edited by Lil aus; Jan 13, 2013 at 05:29 PM. Reason: adding pic
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Old Jan 13, 2013, 05:49 PM
Mad on everything Swash
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To follow on with a ceramic solution
as an example I've found in 6802
single steel bearing is 7.26g
single ceramic bearing is 3.1 g
that is quite a significant weight loss
I hope im helping here...or has this already been covered ?

"The Wiggle movement is the best of the mechanical ways to move the wings for flight. "
Kjell is absolutely correct here , Im totally convinced this method is the best way, it cannot get any easier than simply turning a bearing in this swash action. the engineering is more complex but the end result is simplistic in nature if you know what i mean !
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Old Jan 13, 2013, 08:08 PM
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Originally Posted by KJELL View Post
I like to see a picture or a drawing of your system.
In my spinning test bench I can measure the following things.
Power consumption. Flying speed. Thrust. Flapping frequency. Pressure on wing sides. Accelerations.
Like I said, this design doesn't work.
Options to make it work:
a non-circular axle,
powered rotating collar,
change ball and socket to gimble
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Old Jan 14, 2013, 05:32 AM
Kjell Dahlberg
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I am testing a 3 D Printed VWD with loos steel balls. After many hours running, it is working fine without excessive wearing.
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Old Jan 14, 2013, 10:34 AM
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I am testing a 3 D Printed VWD with loos steel balls. After many hours running, it is working fine without excessive wearing.
Kjell there is plastic ball bearings with glass balls. Since the glass relative weight is almost like aluminum (around 2.4 or 3 times lighter than steel balls) you can save some additional weight. IMO the glass balls will work no worse than steel balls(in combination with plastic ball racers) and also you can integrate the whole plastic bearing in the design because it is made from POM (relative weight around 1.13)and definitely is much stronger than printed plastics and ball racers, for sure are much more smoother .The friction will be lower and probably the gaps tolerances are much more precise. Plastic bearings are more expensive than steel ones but cheaper than ceramic bearings and especially (full ceramic ones)

Just suggestion and appreciate the efforts,spent time and money of all the guys in the thread!

Success to all inventors!

http://www.vxb.com/page/bearings/PRO...FXGRPAodY24ACw
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Old Jan 14, 2013, 01:59 PM
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I am testing a 3 D Printed VWD with loos steel balls. After many hours running, it is working fine without excessive wearing.
What an excellent idea.
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Old Jan 14, 2013, 05:28 PM
Mad on everything Swash
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Good idea Kjell
obviously it runs ok without cages ?
Certainly dismisses the ceramic idea, you are certainly further refined than your letting on is it flyn already

This one is axial not radial.... so does it wiggle or swash

Those POM /Glass bearings look like the way... off the shelf solution and only $8, couldn't find any weight ? they look light ... good lead, thanks !
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Last edited by Lil aus; Jan 14, 2013 at 05:35 PM.
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