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Old Feb 22, 2013, 10:42 PM
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Quote:
Originally Posted by Raften View Post
Seems to be a Nutball with a tail. Cool
That's exactly what I thought! The articulated or segmented tail/fuse certainly adds drag but the flat nature also acts as a lifting body once it gets some forward air speed. A snake or dragon themed paint job would add to the appeal.
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Old Feb 23, 2013, 12:27 AM
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I have resisted building a Nut Ball but building one of these might be needed. A nice Python pattern air brushed on seems in order.
Old Feb 23, 2013, 01:05 AM
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I like it. It's original and no string like a kite. I hope someone can make another with plans. I like the dragon idea. Snake or Dragon it should turn some heads.
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Old Feb 23, 2013, 01:20 AM
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Old Feb 23, 2013, 01:27 AM
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Quote:
Originally Posted by Raften View Post
I have resisted building a Nut Ball but building one of these might be needed. A nice Python pattern air brushed on seems in order.
Definitely must build one of those! I wonder if the tail segments are connected with vertical pivots only?
Old Feb 23, 2013, 02:03 AM
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Originally Posted by Steve 0 View Post
The articulated or segmented tail/fuse certainly adds drag but the flat nature also acts as a lifting body once it gets some forward air speed.
There's lift only as long as the segments are level. As soon as a segment -starts- to roll it loses a bunch of lift without losing any weight.

I've thought of a way to control/'dampen' pitch and yaw variations. Each segment has a 1" piece of soda straw mounted in the center line at the LE and the TE. A piece of CF rod runs the -entire- -length- of the snake, going through every soda straw in every segment. The rod is fastened -only- at the head end. As a gust of wind attempts to push one segment around, that force is partially transferred to each segment in front and behind that segment. And those segments further transfer the force up and down the line.

I *think* that *roll* might also be controlled by using -two- of that style 'long CF rod', each mounted a little to the left and right of the center line. Maybe 15-20% of the half-width. Since the pitch/yaw is moderate by the total strength of two rods (and don't want that to -double-) it'd take further guesstimation/testing to find a slightly smaller size that works for all three axes.

Definitely don't want -too- much control because a big part of the snake look is the serpentine motion. Too much control and it's just a very long stick. Not enough control and it's back to the tail wagging the head.

The amount of control is determined by the diameter of the CF rod. Don't want it to be 0.1" too rigid, and don't want it to be so thin as to be too flexible and/or snap. That'll take a few trials to find out which size is best for a given snake length/weight.

My LHS has different diameter rods in 3', 4', 5' lengths but can be frapped to make the right length. (I've learned to do that kind of lapping with a really cool Spider Wire frap.)

Actually that whole CF rod idea came to me while thinking about how to -accurately- measure CG. Since the segments are only vaguely attached to each other it's be like trying to measure the CG of a piece of rope. That's where the soda straws came in plus a -thick- piece of CF running the whole length that can support the whole weight without sagging too much.

Quote:
A snake or dragon themed paint job would add to the appeal.
Airbrushing Snake Skin Paintjob (3 min 26 sec)


I think I'd do the top side in neutral grey/brown colors and the underside in coral snake red/yellow/black for better visibility.

I thought about a long red tongue but decided that unfortunately the forst turn of the prop would cut it right off. LOL!!

Yeah a dragon would be cool with beard and mane and hands with claws.
Old Feb 23, 2013, 02:13 AM
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Looks to me like the segments might be attached with vertical pivots like this...
Snake Segments (0 min 14 sec)

The slight rolling of the segments might be just from the flexibility of the foam/cardboard and pivots.
Or maybe connected just with rings?
Last edited by djacob7; Feb 23, 2013 at 02:25 AM.
Old Feb 23, 2013, 02:31 AM
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Originally Posted by dedStik View Post
I'd be more inclined to put the head at 6mm and the body segments at 3mm.
Yep I'll agree with that for an 8' snake. Maybe a smaller test/proto/POC 3' snake could be 3mm and 2/1mm. Trying to avoid the sheer -weight-. The prop in the vid looks really tiny and it's gotta drag that whole snake around.
Old Feb 23, 2013, 05:07 AM
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thanks for the great inputs guys,good learnings indeed
double checked the designer's website again but found no further info regarding to the flying snake except the vid only,will update when released
guys who interested in the captioned subject will be greatly appreciated if anyone came up with detailed plan after his successful flights
flying dragon,flying chilopoda after flying snake???
cheers
Sam
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Old Feb 23, 2013, 11:55 AM
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Quote:
Originally Posted by djacob7 View Post
Looks to me like the segments might be attached with vertical pivots like this...
http://www.youtube.com/watch?v=W9rxW...ature=youtu.be
The slight rolling of the segments might be just from the flexibility of the foam/cardboard and pivots.
Or maybe connected just with rings?
I think you got the hinges right. The small amount of roll seems to be related to the torsional stiffnes of each segment. Clearly the segments bend and twist a fair amount in flight, but where the segments meet at the hinges they stay parallel.
Old Feb 23, 2013, 10:23 PM
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the connectors between the segments may possibly used the same ones from his other plane.
https://www.rcgroups.com/forums/show....php?t=1787050
Sam
Old Feb 23, 2013, 11:24 PM
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Originally Posted by samwei1950 View Post
the connectors between the segments may possibly used the same ones from his other plane.
https://www.rcgroups.com/forums/show....php?t=1787050
Sam
Nah those are rigid backbone structures. They -have- to be because all the left side wings are driven by one motor, and all the right side wings are driven by another motor. That's how it steers. If there were 'separate' segments there'd have to be some sort of u-joint to transfer the axle power from segment to segment, with associated massive loss of efficiency.

In the vid check the still shot at 0:55, pure rigid.

Also scroll down in that page to see the assembled fuse with drivetrain. There's not much detail but the CF rods tha run the length of the fuse are not jointed.
Old Feb 24, 2013, 09:53 PM
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There's nothing like trying, so I did. Easy to build; not so easy to fly.
I feared that it would be tricky to overcome prop torque because of the very small "wing" span, and my fears were verified as you can see in the clip.
Next I will try to fly it without the tail...
Snake Maiden (0 min 28 sec)
Old Feb 24, 2013, 10:07 PM
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Great first attempt. What type of connection/hinge/joint did you use between segments?

My suggestions are try using less power, and a smalller prop.

Starting with a 4" prop would be my choice. You may end up with a 5 or even a 6" prop but starting small just means you will not have tons of power to pull out of a bad situation. Starting with a prop too big means huge torque roll.

That's what your video looked like. Just way too much torque roll force for the elevons to try and over come. Flight speed was much faster than what I remember seeing in the first vid. Looked like his had too little power. It was just barely able to stay airborn. Yours powered in!
Old Feb 24, 2013, 10:33 PM
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Good suggestion. I'll try a smaller prop with minimal power.


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