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Old Nov 29, 2010, 06:21 PM
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Yep, much clearer now, and indeed simpler too. I somehow was under the impression that the flybar was above the prop, I have seen too many helicopter rotors . I think it can be simplified even further by making the retainer a bit "squarer" and wider. The outer portion around the red pivot will need to be filed down slightly to allow the prop to tilt. I think it might also be a good idea to key the prop, because I suspect that if it is allowed to spin it will try to align at 90 degrees to the pivot due to inertial coupling. But then again the o-ring might be enough to keep it in place, should be simple enough to test
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Old Nov 30, 2010, 06:27 AM
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I think for this idea to be practical, the prop has to be on top for easy change out.

The top piece of this design concept could be made from a typical prop saver. Just drill a cross hole for the "feather hinge" pin , and replace the screws with ball end screws.

I'm still trying to think of a simple way to make the bottom piece.
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Old Nov 30, 2010, 10:16 AM
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mill from solid. Most of it can be milled on a drill chuck. the most complex bit is cutting out the central slot. Btw, you could have the bottom part in two pieces, each with its set screw to have infinitely adjustable phase angle. A way to make a quick prototype would be to get a hold of 2 large collets, a piece of deep AL C channel and a prop saver. Drill a hole across one collet and use it to hold the flybar pivot. File two flats in the other so that it will narrowly fit in the C channel, then drill a hole in the bottom of the C channel to let the shaft through and two holes in the top to hold the prop saver. Finally file the sides of the prop saver to fit in the C channel and drill it for the ball links and the pivot. The C channel should be kept in place by being sandwiched between the two collets, but it might be better to add another hole and get it to screw onto the upper collet. You don't need the flybar pivot to go all the way through the bottom collet, you can just remove the thread from the end of a couple of bolts and bolt them to the outside of the flybar frame
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Old Nov 30, 2010, 01:22 PM
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mill from solid. Most of it can be milled on a drill chuck. the most complex bit is cutting out the central slot. Btw, you could have the bottom part in two pieces, each with its set screw to have infinitely adjustable phase angle. A way to make a quick prototype would be to get a hold of 2 large collets, a piece of deep AL C channel and a prop saver. Drill a hole across one collet and use it to hold the flybar pivot. File two flats in the other so that it will narrowly fit in the C channel, then drill a hole in the bottom of the C channel to let the shaft through and two holes in the top to hold the prop saver. Finally file the sides of the prop saver to fit in the C channel and drill it for the ball links and the pivot. The C channel should be kept in place by being sandwiched between the two collets, but it might be better to add another hole and get it to screw onto the upper collet. You don't need the flybar pivot to go all the way through the bottom collet, you can just remove the thread from the end of a couple of bolts and bolt them to the outside of the flybar frame
All I have is a drill press and some hand tools.
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Old Nov 30, 2010, 01:38 PM
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That is what he is talking about ... you can do simple lathe and mill jobs like these parts with a simple drill press and go to harbor freight and buy a drill press vise which will allow you to make a device to hold the lathe / mill bit and you can do simple lathe work with the drill press . it won't be real accurate ,,but close enough for this .
Matter of fact the Bolton 12 " mini lathe/ mill combo I have is just that a lathe with a vertical drill press that does the mill work .
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Old Nov 30, 2010, 01:43 PM
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Tha's all us DIYers need. I make a lot of that kind of stuff from plastic kitchen cutting board.
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Old Nov 30, 2010, 03:56 PM
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I'll have t check into the drill press vice then!

I was thinking that if I can find some aluminum tubing that the prop adapters will fit into nicely, I might be able to use a prop adapter at the top and another prop adapter glued into the tube at the bottom to form this piece. Now the amount of machining will be getting pretty low, it might even be do-able?
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Old Nov 30, 2010, 04:35 PM
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The biggest problem you will have is to drill holes on the side of the prop adapter. A drill press vise is pretty much essential for that. And filing the spot flat by hand will help too
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Old Nov 30, 2010, 05:41 PM
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grind a flat ... or pick up a drill set punch at harbor also ... some are even self setting ... by just pushing down on them and they make the little divet for the drill to start in
I personally like to make (well I can with a lathe ,, not sure you could with just a drill press) , make a drill hole centering tube square. Which is a larger / thick square with a hole the size of your shaft drilled thru it and that is pre drill to the hole size and centered that goes snuggly around the shaft that you want to make a centered / prefectly vertical hole through . This way you clamp the square hole jig in the drill vise and line up the drill bit in the drill with the hole in the drill hole jig , making sure it passes easily through top and bottom holes . Slide the shaft in to where you want the hole to be and drill it .. and presto it is centered and perfectly vertical as the outer jig guides the starting of the bit and keeps it from slipping off the round shaft one way or the other and letting it go off center or off the vertical cg.
Hope this makes some sense as I don't have one here right now to take a picture of .
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Old Dec 01, 2010, 08:43 PM
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simpler still

OK, if we go with a 90degree flybar it can get real simple.


The extra long bolts (blue) are used to secure the o-ring and they are the flybars too.

The red pin is the feather hinge pin as before.

One locking screw (yellow) holds the base on the motor shaft. It can be in any convenient location.
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Old Dec 01, 2010, 09:51 PM
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News update! I got tired of V1 when it didint perform all that well at JR (it was giving me too many problems) V2 uses gws 002 motors (Dave at radical RC helped me pick e'm and also machined out the BCX2 aluminum heads with his lathe! Theyre actually straight now ) I just test flown V2 in my basement and its hoverin at alot less throttle with almost all the equipment on it. After I get the elevator servo installed and it painted i'll post pics. Im taking it to the HEFI up in Geneva OH this weekend. i really need that conter rotating head peices!!!!
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Old Dec 02, 2010, 07:07 AM
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News update! I got tired of V1 when it didint perform all that well at JR (it was giving me too many problems) V2 uses gws 002 motors (Dave at radical RC helped me pick e'm and also machined out the BCX2 aluminum heads with his lathe! Theyre actually straight now ) I just test flown V2 in my basement and its hoverin at alot less throttle with almost all the equipment on it. After I get the elevator servo installed and it painted i'll post pics. Im taking it to the HEFI up in Geneva OH this weekend. i really need that conter rotating head peices!!!!


I'm going to get the "now very simple" lower yoke pieces made by a machinist. I'll post the detailed drawing for this and the mod to the prop saver when I get them done.

BTW I've already built a prototype VTOL similar to yours. I tried it with an over sized horizontal stabilizer to try to dampen the pitch movement in hover, but it would still oscillate in pitch getting worse with each cycle. The stabilized props are needed and are a great solution.

On my prototype, I made the motors tilt inward a little to see if this would help with roll stability. The tilt angle is adjustable so I can try different adjustments. I'll report on the effect of this once I get the stabilized props mounted and worked out.
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Old Dec 02, 2010, 04:38 PM
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On my prototype, I made the motors tilt inward a little to see if this would help with roll stability
I have never tried in ... but out by 3 to 5 degrees really seems to help
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Old Dec 02, 2010, 06:17 PM
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I have never tried in ... but out by 3 to 5 degrees really seems to help
My thinking was that the rotors "tilted in" would provide roll stability during hover in a similar fashion that dihedral does in a flying airplane.

Wouldn't "tilt out" make it more roll unstable in hover?
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Old Dec 02, 2010, 06:42 PM
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Ask the engineers on the V-22 and that is why I did it on my V and I just did swash plate tilt not the whole nacelle like they do and I could tell a difference . Might be different for your bird ... but like I said I never tried in though ... it might work too !!!! That is what makes this R/C VTOL so fun as there are no set aerodynamic principals set out for us to follow and everyone can just test it out and have the fun of seeing something new come to life !!!!
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