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Jun 01, 2020, 11:36 AM
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Question

Tail heavy or nose heavy?


Flying Foam Sheet Used as Testing Platform for Matek Flight Controller (2 min 40 sec)


is that tail heavy or nose heavy? ideas anyone?

the flight part is at 1.45m
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Jun 01, 2020, 01:10 PM
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balsa or carbon's Avatar
You can use a flying wing CG calculator like this one : http://fwcg.3dzone.dk/ Some people are confused by "sweep distance" .... sweep distance is root chord minus tip chord . Include the elevons in total chord measurements .

Or you experiment by moving the battery forward/rearward in small increments .... until you get the flight you want .
Jun 01, 2020, 02:15 PM
Registered User
Yep, looked pretty much like tail heavy behavior.
You also have extremely low aspect ratio, so it might be very sensitive in roll.
Why not make things easier on yourself and do a Simplest Simple Delta or the like. That way you will know where the CG is supposed to be...
Jun 01, 2020, 04:15 PM
Flying a Falcon or a 3D model.
fauconnier's Avatar
To answer your question, your wing is almost rectangular, your CG should be near 25% to 30% in front like a trainer wing. You have a lot of weight in the back half, like your motor and servos and your battery is small. I am sure your plane is tail heavy.

You design is questionable.
Last edited by fauconnier; Jun 01, 2020 at 04:21 PM.
Jun 01, 2020, 08:11 PM
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thank you all for your replies, i'm actually waiting for materials and parts to arrive at the moment so just playing with what i have, but the idea of this -
"Simplest Simple Delta" scratch built RC Flying Wing (2 min 53 sec)
- Simplest Simple Delta or the like, looks very good so thanks for that
Jun 01, 2020, 09:04 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by LongRange_UAV_4G
thank you all for your replies, i'm actually waiting for materials and parts to arrive at the moment so just playing with what i have, but the idea of this - https://www.youtube.com/watch?v=5_GcZzp2b7g - Simplest Simple Delta or the like, looks very good so thanks for that
Here is the thread for the Simplest Simple Delta : https://www.rcgroups.com/forums/show...h-simple-plans

The 30" SSD is more agile , the 40" SSD is more docile .
Jun 01, 2020, 09:46 PM
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Piece's Avatar
It takes a surprising amount of weight at the leading edge to get any near-square planform to fly properly. All that stuff that's spread along the centerline (especially the motor and battery) should be bunched up at the front. It's almost impossible to build one that's truly nose-heavy, and most people who build them are aiming for a flight envelope where relative tail-heaviness is desirable anyway.

There's no reason it won't fly if you rearrange it to balance, but it's easier if you go with a higher aspect ratio.
Last edited by Piece; Jun 06, 2020 at 03:50 AM. Reason: Lulz, oops
Jun 01, 2020, 09:51 PM
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I should've watched the video before posting

Have you tried to fly this thing without the stabilizer? I ask because its static margin is almost definitely negative based on the equipment layout, and not just by a little. Just curious if I've overlooked something or if the stabilizer is really that good.
Jun 01, 2020, 11:06 PM
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Quote:
Originally Posted by Piece
There's no reason it won't fly if you rearrange it to balance, but it's easier if you go with a lower aspect ratio.
Did you mean higher aspect ratio?
The aspect ratio he's got now is very low and makes roll control very sensitive.
AR of the SSD (or similar) is still low, but much more reasonable...
Jun 01, 2020, 11:25 PM
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the stabilizer was off, i planed to turn it on once i got to a point where i can fly and land it
Jun 01, 2020, 11:28 PM
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hang on, i suppose i could just cut two triangles and extend the wings to make a delta?
Jun 02, 2020, 02:40 AM
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Piece's Avatar
Quote:
Originally Posted by nuteman
Did you mean higher aspect ratio?
The aspect ratio he's got now is very low and makes roll control very sensitive.
AR of the SSD (or similar) is still low, but much more reasonable...
Yeah, higher AR. Just typing faster than I'm thinking
Jun 02, 2020, 03:38 AM
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Piece's Avatar
Quote:
Originally Posted by LongRange_UAV_4G
the stabilizer was off, i planed to turn it on once i got to a point where i can fly and land it
Wow, I wouldn't have expected that at all. How far back is the balance point right now?
Jun 02, 2020, 04:06 AM
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balance point


Quote:
Originally Posted by Piece
Wow, I wouldn't have expected that at all. How far back is the balance point right now?

it was about in the middle it's now 4/10 to the front, i'm thinking to extend the wings to make a delta and add some dihedral, what do you think?
Jun 02, 2020, 04:27 AM
Registered User
You could also cut a triangle out of the front of the wing to make it more of a delta.


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