Aviation models 87"Yak cg

[danny calderone]

Hey guys, I'm just buttoning up my first giant scale project, 30% AM Yak 54... the manual says to start the cg at 6.5" from leading edge, the closest I have been able to get it is around 7.5". Is this going to be ok ar what? I understand making a plane a little tail heavy can make it sketchy in flight, but I think they have you set the cg conservatively at first in the manual. And I already fly 3D pretty well, so Handling the balance shouldnt be so bad, just looking for some experienced perspective before the maiden.
Thanks in advance.
Danny

[WTF]

These fly well balance on the wing tube (wings off) or slightly tail heavy off the wing tube.

[yakattack]

Mine balanced between 7.5-8 and it flys awesome.

randy

[Mike c.]

wow, my yak is at 6.5" back and it flys tail heavy. I would try to make the tail as light as possible and try to put the batteries and stuff in the front.

[danny calderone]

Well, I flew the maiden tonight, still quite a bit more tail heavy than I like, afraid I'll have to add weight. Just dont have anything left to move forward, but at 16.8 lbs auw right now, I should be ok. I'll post back later on, after more flying.

[jon595]

The bottom of the rudder is plywood laminated to balsa. I took 2 different size forstner bits to it. Mine had 2 hardpoints in it, 1 of which is now a pile of dust on the floor. 1st hardpoint is for the pull-pull that exits out above the stab, 2nd one is lower forward edge (and it's huge). I also drilled 2 holes in the thick plywood plate where the rear gear monts. I had the same scheme as your avitar and hated it, she is in the bones now.

[torquen]

	Quote: Originally Posted by Mike c.
	wow, my yak is at 6.5" back and it flys tail heavy. I would try to make the tail as light as possible and try to put the batteries and stuff in the front.

Is this the yak in your Avitar? Looks like the Avitar is a KMP yak. If so they are not the same plane as the SD.

[JeeUm]

I recently flew mine at 6.75" and it was too tail heavy for my liking. Still flew well, but super sensitive on the elevator and it would climb out of a inverted 45.

Got it moved forward to 6.25" now and also with carbon tubes and gear the weight is down to 16.5lbs . I'm dying for this snow to melt so I can try it again.

[Mike c.]

	Quote: Originally Posted by torquen
	Is this the yak in your Avitar? Looks like the Avitar is a KMP yak. If so they are not the same plane as the SD.

Yes, it is my KMP yak, but they are ALMOST identical. I flown a SD yak with the same CG and it flys very close to mine, only because it is a pound heavier than my yak. Mine is at 18.5 lbs and his is 19.5 lbs.

Here is a video of it.
http://www.flyinggiants.com/gallery/...yak&perpage=15