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Old Feb 25, 2013, 11:55 PM
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I couldn't help myself but to laugh out loud tonight! No disrespect intended (to anyone), but does anyone else find it kinda funny that a bunch of North Americans are trying to reverse engineer a Japanese idea....

FWIW after viewing the video many times I think the segment hinge design is largely irrelevant. A couple pin hinges glued into 2mm depron ought to work just fine. I do agree that a high KV motor and small prop would be best - less torque to deal with.
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Old Feb 26, 2013, 12:04 AM
Fremont, CA
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Yep, the tables have turned since Deming showed the Japanese how to do quality control.
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Old Feb 26, 2013, 12:32 AM
Fremont, CA
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I tried "simple loops" but they don't allow you to fold the snake like he did in the video. See first video. You can make the loop work by making a curved slot as shown in the video. However, simple loops allow you to fold "head over heels" like I show in the second video. The last video shows how I made the connections with a "simple pin".
00001 (0 min 20 sec)


00004 (0 min 13 sec)


00002 (0 min 21 sec)
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Old Feb 26, 2013, 01:21 AM
Fremont, CA
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I'm convinced that he must have a roll gyro. Take a look at the GIF sequence that follows and watch how vertical and stable the head is during the launch. Even the best of flyers would have some roll happening during launch until he has it in a steady state.
http://www.flickr.com/photos/danjaco...n/photostream/
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Old Feb 26, 2013, 06:40 AM
Kamikaze Ace
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Been pondering the hinge setup for the last two days. Watching the video, and still shots to see how it works. And I'm beginning to think as has been suggested that there is no up/down or twist in the hinge. It's only a pinned arrangement to allow left/left right movement. All else is in the material of the body/tail itself. Maybe, more then likely, I was over thinking it.

Looking around the shop, I found a "procured" coroplast sign to use for the head. And instead of some 2mm Depron I think I found some plastic sheeting that may be the ticket. Light as Depron, flexible, and less chance of tearing out the hinge points.
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Old Feb 26, 2013, 07:46 AM
gpw
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Sorry guys , but think you’re focusing on the hinge thingie' and not what’s really going on ... The best way to reverse engineer this is to start as simple as you can , and then complicate that if it doesn’t work ... it’s obvious the “snake” is Very Lightweight construction ... as it breaks at the end of the vid. You can see the tail material bend and flex, so you know it’s VERY thin and LIGHT ... Notice , losing part of the tail Did Not affect the flight of the Main Plane (essentially the tow plane) .
It’s like towing banners , once you establish the orientation of the front of the banner , the rest just follows along ... Schmaybe’ why Ducks fly in a line ... ???
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Old Feb 26, 2013, 10:00 AM
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DeBary, FL
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Quote:
Originally Posted by Hepdog View Post
I couldn't help myself but to laugh out loud tonight! No disrespect intended (to anyone), but does anyone else find it kinda funny that a bunch of North Americans are trying to reverse engineer a Japanese idea....
What goes around keeps going around.

"Failure to learn how to stand on the shoulders of giants dooms success to merely knee-high."

Unfortunately I almost -never- have an original idea. My forte (in any field) is recgnising genius and pushing it further and harder.

Yes I am frequently (read: 'always (always)') accused of overthinking. The downside is that it takes me longer to do anything that requires thought or 'originality.' The upside is that my v1s are 98% successful.
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Old Feb 26, 2013, 10:33 AM
DIY Mania from Taiwan
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well,have material prepared after learned from you guys
head: 5mm & 2mm depron,
hinge:0.5mm FRP sheets,plastic nuts(will cut short & drill 2mm hole) and toothpicks
first segment :2mm EPP
rest segments :1mm EPP.....tried to maintain as light as possible
will keep lipo underneath the head to have lower CG for flying stability
comment if any
cheers
Sam
PICT1791
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Old Feb 26, 2013, 12:32 PM
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This would also make an excellent flying Chinese dragon with a little bit more attention to the details. Very cool.
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Old Feb 26, 2013, 01:32 PM
AKA Don
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United States, MI, Houghton Lake
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Quote:
Originally Posted by samwei1950 View Post
well,have material prepared after learned from you guys
head: 5mm & 2mm depron,
hinge:0.5mm FRP sheets,plastic nuts(will cut short & drill 2mm hole) and toothpicks
first segment :2mm EPP
rest segments :1mm EPP.....tried to maintain as light as possible
will keep lipo underneath the head to have lower CG for flying stability
comment if any
cheers
Sam
PICT1791
I think you are on the right track! What power system are you planning to use?
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Old Feb 26, 2013, 04:43 PM
TonyS
United States, AR
Joined May 2010
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Quote:
Originally Posted by samwei1950 View Post
well,have material prepared after learned from you guys

Sam
I think that is a great start! Thanks for including the dimensions in your picture descriptions. I haven't yet settled on the size of the body and segments, but was thinking a little bigger. I like your size better.

I agree with keeping as much of the weight of the 'head' as low as possible. I also plan to keep all equipment as close to center line as possible.

I differ in materials I have chosen to use. I have the .8 material from plastic document protectors (polypropylene?) for hinges. For the head and body segments I have not yet decided primary materials. I was thinking 5/3/2 mm depron like you. But, I am also thinking of using MPF (4.75 mm) with tape reinforced hinge areas for all but the last body segments.

TonyS
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Last edited by tonystro; Feb 26, 2013 at 04:53 PM. Reason: to mention size of craft
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Old Feb 26, 2013, 05:00 PM
Fremont, CA
United States, CA, Fremont
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Do any of you guys think that it might be a good idea to fly the head alone first and drag the tail after a successful head flight? Although the tail stabilizes the pitch somewhat.
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Last edited by djacob7; Feb 26, 2013 at 05:06 PM.
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Old Feb 26, 2013, 06:33 PM
AKA Don
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Tail could be one piece of mylar or nylon taffita fabric as in the dragon kite below.
The one pictured is made of nylon taffita and sold by Into The Wind at http://www.intothewind.com/shop/Trad...in_Dragon_Kite You can see a video of it flying at that site also.

I have a similiar looking kite made of mylar. It was much less expensive. It has a 50' tail.


A PBF and a kite tail would make an impressive RC flying snake.
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Old Feb 26, 2013, 06:38 PM
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Quote:
Originally Posted by gpw View Post
Notice , losing part of the tail Did Not affect the flight of the Main Plane (essentially the tow plane) .
It's kind of hard to tell since except for a few moments there was very little in the way of 'totally controlled' flight. Some of it when the wind was smooth was -excellent- absolutely beautiful which is why I'm so interested in this. But the wind (often) -varies- every few feet, and it particularly affects ultralight models such as this. Ultralight, yet with tons of surface area, which make the effects of variable wind that much worse.

Quote:
It’s like towing banners , once you establish the orientation of the front of the banner , the rest just follows along ...
I don't think that's a very good analogy because a banner has no horizontal surface area, offers no lift on its' own behalf, and is all pure drag. In a sense that's easier -because- the pilot doesn't have to think about or take into account any lift offered by the banner.

The snake has *tons* of lift, given surface area. *UN*fortunately it's mostly only 'vaguely under control.'

A better comparison might be aerial tow where the towed plane -does- have its' own lift. Now I have no RL FS or model experience with tow but have talked about it with RL pilots and read a bunch. The way I understand it is that for the towing plane to 'survive' the towed plane must lift off first and, until it's released, always remain -above- the towing plane.

With the flying snake the 'towed tail segments' are (almost) always -below- the thrust of the head segment. No that's not the right way to say that. The towed segments are almost always below the altitude of the head segment, though vaguely in like with the thrust regardless of how steep the incidence is.

With that the whole structure is almost always flying purely on the prop - the head segment 'wing' (both horizontal and vertical parts) does its' best to add some (vague) stability to the direction the pilot steers it.

So the reason I keep harping on the hinge is that it's about the only place we can try to add -some- stability to this 'mostly out of control' structure.

I'm working on one that uses a pivot similar to djacob7's though more rigid.
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Old Feb 26, 2013, 07:43 PM
Fremont, CA
United States, CA, Fremont
Joined Jan 2009
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bz1mcr: I think the kite is a great idea and just as interesting as the snake. Easier to make too; just buy one for a few bucks LOL!
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