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Old Feb 27, 2013, 12:49 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
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Quote:
Originally Posted by bz1mcr View Post
I think you are on the right track! What power system are you planning to use?
I have an old 36 gram 1600kv BL in hand which will be installed today
keep on building.....
5mm depron glued on the bottom with epoxy after plywood (for motor mount) & frp sheet
all the tail segments bottom are CA glued with frp sheets (2 pieces each)
pics 1,2,3 & 5 are the bottom view,fyi
cheers
Sam
PICT1800
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Old Feb 27, 2013, 12:41 PM
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Joined Sep 2010
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Just ran across this and it is similar to me using a version of nutball with 30 ft of crepe paper being towed behind it and dogfighting to be the last one flying with the longest segment.

Observations:
1) plane flies like a trainer--elevator and rudder-- go to video at 3:41--see black tube connecting the 2 elevators together. Also, see rudder vertical cut line plus there are only 2 servos.
2) Use small motor and a flat pitch prop just like 3D flyers- this will give you slow speed--look at his launches in video-also tail sections will not rotate and snap off if flying gentle. Too fast, that's the end.
3) First fly plane(no tails) and get CG. Do not worry about CG(no problem with 30 ft of paper being added.) after that. Look at video at 3:02 and guess what-his battery is flopping in the air) while he is flying.. Not an issue.
4) The main issue is -what material and thickness-what type of joint is he is using?
5) The tail section has to be absolutely light.

Since I don't have any small motors, I am out. But here is a suggestion for material.
While building my autogyro, I made my blades out of 3mm "Foamcell" and to me, it duplicates the movements of his materials.
Going to think awhile on how and what he used for joining sections.
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Old Feb 27, 2013, 10:40 PM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
2,006 Posts
OK,completed the first one just minutes ago
2mm depron glued on top and 7' X 3.5' GWS prop installed.
all the electronics are fixed under the head to maintain lower CG.
a slot cut for 3S 850mah lipo and 30% CG from LE.
a 6mm plastic screw with 2mm hole drilled for the first segment with a metal pin attached underneath,it's detachable,the rest segments are 4mm platic screws with toothpicks inserted,
light yellow waterborne acrylic paint for the final touch up
will come back with vid,wish me luck guys
cheers
Sam
images (3)
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Old Feb 27, 2013, 10:52 PM
Fremont, CA
United States, CA, Fremont
Joined Jan 2009
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Looks good, Sam! I'm holding my breath - good luck!
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Old Feb 28, 2013, 11:25 PM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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I love the looks and I think your construction should work pretty well.

BUT, Looks like the prop diameter is about 80% of the wing span. That is going to want to torque roll something fierce. I suggest the prop size be reduced to 4 or 5" max. Well under 50% of span.
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Old Mar 01, 2013, 01:28 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
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so,maiden the snake this morning
first tried the head.......
set the CG at 180mm behind LE(snake head size 340mm X 420mm),trimmed a bit of roll and snake head flies great in the air,touched only rudder all the way around
next,connected the tail segments......
it became nose heavy and crashed
different CG needed when flying this new toy???
will come back soon
cheers
Sam
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Old Mar 01, 2013, 01:42 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
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Quote:
Originally Posted by bz1mcr View Post
I love the looks and I think your construction should work pretty well.

BUT, Looks like the prop diameter is about 80% of the wing span. That is going to want to torque roll something fierce. I suggest the prop size be reduced to 4 or 5" max. Well under 50% of span.
thanks for the nice words
the prop size so far is OK for the flight(my maiden vid).
the torque from the prop can be eliminated by minor roll adjustment of the elevon.
the myth is.....a rudder is needed for the snake because I'm convinced Japaness flying snake have 3 servos on board.
regards
Sam
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Old Mar 01, 2013, 02:25 AM
Fremont, CA
United States, CA, Fremont
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Congratulations on the maiden, Sam! At least you got the head flying. Looking forward to seeing the tail too ;-)
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Old Mar 01, 2013, 08:12 AM
TonyS
United States, AR
Joined May 2010
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Sam,

Congrats on successful flight of the snake head, as well as completion of "first test flight" of the tail section. You are way ahead of me, I just got my patterns cut last night.

I could be very wrong, but I don't think "...it became nose heavy and..." When I watched the video, over and over, it appears to me the 1st and 2nd tail segments lift up, pulling the rear of the head up as well. If, as was mentioned in earlier posts the segments each act as an airfoil this would be the behavior we should expect.

I think you need to move the CG more toward the rear as you add the tail. Perhaps adding one tail section at a time would allow better assessment of the effect, and the opportunity to adjust CG one step at a time?

TonyS
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Old Mar 01, 2013, 08:58 AM
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Your takeoff was beautiful, nice and steady, until the fluttering and wild gyrations, then nose down. Speed is too fast, should get air born and reduce throttle. Like tonystro said, do one section and see how it goes on takeoff, flying and landing. Then repeat with two, etc.

Don't change CG yet. The crepe paper as it is cut off does not effect CG as you fly.

Good luck.
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Old Mar 01, 2013, 09:29 AM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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Congratulations !
You are getting close.

Why do you say it became nose heavy?

I do not see anything in the video that suggests that to me.

Perhaps you had more test flights not shown in the video.
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Old Mar 01, 2013, 11:12 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
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Quote:
Originally Posted by tonystro View Post
Sam,

Congrats on successful flight of the snake head, as well as completion of "first test flight" of the tail section. You are way ahead of me, I just got my patterns cut last night.

I could be very wrong, but I don't think "...it became nose heavy and..." When I watched the video, over and over, it appears to me the 1st and 2nd tail segments lift up, pulling the rear of the head up as well. If, as was mentioned in earlier posts the segments each act as an airfoil this would be the behavior we should expect.

I think you need to move the CG more toward the rear as you add the tail. Perhaps adding one tail section at a time would allow better assessment of the effect, and the opportunity to adjust CG one step at a time?

TonyS
great idea,will do that accordingly
regards
Sam
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Old Mar 01, 2013, 11:27 AM
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Old Mar 01, 2013, 11:45 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
2,006 Posts
Quote:
Originally Posted by bz1mcr View Post
Congratulations !
You are getting close.

Why do you say it became nose heavy?

I do not see anything in the video that suggests that to me.

Perhaps you had more test flights not shown in the video.
thanks
you are right, there were 3 times test flight with tail segments.
first shot (no vid).......
it went straight nose down when CG same as head only,prop broken
second toss (with vid,but not well recorded,will post tomorrow)..........
moved CG backward for 10mm,and the snake went up a little and down again.
third try........
moved CG backward again for another 10mm and as vid shown above.
lost 3 props but great fun gained
cheers
Sam
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Old Mar 01, 2013, 11:49 AM
Canadian Bacon
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Kingston, Canada
Joined Jun 2004
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Some food for thought. If the next one or two sections are too tight vertically to the front piece, the tail cannot go down when you give up elevator. In fact it may be just the opposite where the elevators may act like flaperons, where when the flaperons go down, it causes the nose to go up. Just food for thought. Wadya think?? On my way down to the local sign shop this afternoon to see if I can pick up some of the thin 1/8 in. coroplast to crank out one of these things.

Gord..
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