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Old Feb 04, 2013, 06:27 PM
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Wargassm's Avatar
United States, CA, Lake Forest
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Originally Posted by XSTORM View Post
My SU 47 is going to fly on Saturday

I would not like to have of problem with a bad center of gravity

Is that of the note LANXIANG correct?
thats right 200mm back from leading edge right behind the canards.

I balanced mine but it was still tail heavy in air. REcomend going back to 25mm-30mm range.
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Old Feb 04, 2013, 08:41 PM
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United States, NM, Clovis
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Originally Posted by Wargassm View Post
thats right 200mm back from leading edge right behind the canards.

I balanced mine but it was still tail heavy in air. REcomend going back to 25mm-30mm range.
War, so are you recommending to cg at 225mm then? Thanks.
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Old Feb 05, 2013, 08:25 AM
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France, RA, Saint-Cyprien
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Originally Posted by hklagges View Post
Warning: With that weight, it will be a nightmare to fly. Mine did weigh 2.800 gram. It could only be flown fast, or faster !

Good luck,
Henrik

PS: I'd probably have a CoG a bit more back than on your picture, but that is a foggy memory.
I think that I did not understand what you want to say

Your SU 47 weighs 2800 grams?

And you find my SU 47 too heavy ?

The weight does not worry me.

A HABU 32 fly very well and weighs 800 grams more, for a length of 250 mm less
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Old Feb 05, 2013, 05:20 PM
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Originally Posted by DamonH View Post
War, so are you recommending to cg at 225mm then? Thanks.
no not 225m, i had typeo''

its 20-30mm back from leading edge of wing right behind the canards.

25-30mm is more to the sweet spot.
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Old Feb 05, 2013, 05:38 PM
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United States, NM, Clovis
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Originally Posted by Wargassm View Post
no not 225m, i had typeo''

its 20-30mm back from leading edge of wing right behind the canards.

25-30mm is more to the sweet spot.
Ahhhh....so more like 170-180mm from wing leading edge? That could have been ugly to move back to 220-230mm if the 200mm was tail heavy....lol.
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Old Feb 06, 2013, 12:46 PM
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Originally Posted by DamonH View Post
Ahhhh....so more like 170-180mm from wing leading edge? That could have been ugly to move back to 220-230mm if the 200mm was tail heavy....lol.
no not 170mm-1800mm, 20-30mm starting from leading edge of wing, or where the cheater holes for air intake on bottom of the plane.
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Old Feb 06, 2013, 12:48 PM
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Originally Posted by Wargassm View Post
no not 170mm-1800mm, 20-30mm starting from leading edge of wing, or where the cheater holes for air intake on bottom of the plane.
LOL....now I gotcha! I thought you were moving that amount from the recommended cg in manual.
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Old Feb 06, 2013, 06:21 PM
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Originally Posted by DamonH View Post
LOL....now I gotcha! I thought you were moving that amount from the recommended cg in manual.
I'll be redoing my CG tonight, just got her repaired.

im shooting for 25mm back.
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Old Feb 07, 2013, 05:00 PM
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Munich
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Originally Posted by XSTORM View Post
I think that I did not understand what you want to say
Your SU 47 weighs 2800 grams?
It did so, yes. I built it from scratch with different fans, motors, ESCs, freewing TV nozzles, thicker power cables, large battery, too much epoxy glue, carbon spars in the wings etc. It was heavier than the stock plane.

Quote:
And you find my SU 47 too heavy ?
All I am saying is that mine appeared heavy for the wing area, and it had to be flown either like a rocket or not at all. It did not like to go slow.

Cheers,
Henrik
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Old Feb 08, 2013, 02:38 PM
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Originally Posted by hklagges View Post
All I am saying is that mine appeared heavy for the wing area, and it had to be flown either like a rocket or not at all. It did not like to go slow.

Cheers,
Henrik
Yep. And at around half throttle it starts to behave "tail heavy" - nose goes up. That's a stall at wing root. Unless you go WOT the speed will drop further, it will go into high-alfa, then tip-stall into the ground.
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Old Feb 08, 2013, 03:32 PM
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What was wot 2400 watts?? so at 1200-1400 watts it would stall?
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Old Feb 08, 2013, 03:49 PM
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I've yet to maiden mine (weather) but from reading this thread here lately it sounds like this plane isn't a good flyer
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Old Feb 08, 2013, 04:57 PM
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dallas tx
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Some have left that impresion, but others have said, " that if the cg is right, and control throw good. Its a good flyer". Look at some of the video's. Im still building mine.
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Old Feb 09, 2013, 01:23 AM
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France, RA, Saint-Cyprien
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Originally Posted by hklagges View Post
It did so, yes. I built it from scratch with different fans, motors, ESCs, freewing TV nozzles, thicker power cables, large battery, too much epoxy glue, carbon spars in the wings etc. It was heavier than the stock plane.


All I am saying is that mine appeared heavy for the wing area, and it had to be flown either like a rocket or not at all. It did not like to go slow.

Cheers,
Henrik
My SU 47 made its first flight

I find that it flight well enough

It is more to complicate that my MIG 29 LX but rather easy rest

The catastrophic weather conditions

Wind rather hardly 35 kmH
Some snow fell
It spanked only 2C

I have of to land in 2 minutes 50 seconds because I broke down of lipo

I had made too many essays for the ground before taking off

http://www.youtube.com/watch?feature...&v=acsAKB2QCg8
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Old Feb 09, 2013, 05:32 PM
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Originally Posted by capt soap View Post
What was wot 2400 watts?? so at 1200-1400 watts it would stall?
Mine is around 900W half throttle (CS480 motors, stock fans). It will fly fine straight half throttle but turns or climbing is where stuff happens.
Wing profile is symmetric - great for speed but not slow flying. Plus canards cause turbulence at wing roots. You go slow, pull up and suddenly nose points 45 degrees up as 1/3 of the wing is stalled.
I think a good illustration of this plane's flying characteristics is video on Bananahobby site. Compare what Pete does with Mig-29 and this one (that's a second video for su-47 there. On the first one he was flying it just in circles. Around 5:30 is a good illustration how this plane stalls)
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