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CG on Versacopter too far back.

#1
I built the versacopter v2 according to Josh's video. I setup and tested everything and I am about ready to fly but... I checked the cg and it's way too far back. Which is wierd because my naze 32 and vtx are in the front of the aircraft. I also have a board camera mount at the very front. To get the cg right I have to push my battery all the forward against my camera. By doing that only one strap is holding the battery, so I would have to reopen every and move the two straps forward. Is anyone else having problem with their cg? Did I build the versacopter wrong?
 
#2
I could be wrong, but I dont think CG has to be perfect for a quad. That's what the flight controller is going to fix for you.

I know both of my quads (QAV 210 and QAV-X) are both back heavy. As long as you arm your quad on a level surface the flight controller will spool up the rear motors more to counteract the shift in CG. Also if you think about it, as you fly and tilt your quad forward, the CG point is going to shift forward with the tilt.

When you take off, give your quad a little forward pitch and youll be fine.
 

jack10525

Active member
#3
Yeah but from watching the build video it should still balance in the middle. If you fly it ass heavy I think you are just asking for problems.
 

PsyBorg

Wake up! Time to fly!
Mentor
#4
It is probably a good thing you found CG off. Having the Flight controller not mounted as close to center as possible is bad. That HAS to be center for it to be able to function correctly. Yes it CAN still fly but it will be over compensating in one axis and you will end up smoking things from over work. Did you by chance mount all your esc's and receiver in the back by chance?

If you don't mind post a picture with your versacopter open so we can see how things are set up. I have one and I run a go pro wannabe camera, and the board camera at the front, the vtx and antennas at the rear. My fc is dead center and the receiver is towards the front. That balances out nicely and puts my batteries dead center. Here is a pic before I got the newer go pro style camera and it was still nicely balanced and quite agile. I had upgraded to 30 amp esc's which I placed out on the arms for better air flow and balance for the roll access to make it closer to that of the heavier pitch access.

Rebuild 7.jpg
 
#5
My esc's are where Josh mounted them in the versacopter v2 build. My naze 32 is mounted where Josh mounted it in the naze 32 rev 6 setup video. Which is on the closest screw hole to center (because the screws that hold the side plates are in the center). My transmitter is bit more forwards than center. Although my receiver is pretty far backwards. I ordered the camera mount flite test sells which should move the cg a bit more forwards.
Photo on 03-01-2017 at 20.04.jpg
 
Last edited:

PsyBorg

Wake up! Time to fly!
Mentor
#6
The way the Versa is built its pretty hard to not be balanced without fpv gear. You hold it by the center screws and it balances near perfect. When you add a FPV cam the weight tilts forward but is pretty much countered with the antenna mushroom in the rear. The picture you sent looks like it should be well balanced.

What battery are you using? Is it a short battery like the 4s 1300 lumenier graphenes or is it the longer 3s 2200 they recommend in the build? The strap placement was designed for the 3s 2200 size batteries and could be a problem with the shorter lower MAH batteries.

How far off is the balance without a battery? Even with my FPV camera out in front and lower on the Versa it is only slightly nose heavy even now with out a vtx or antenna or even a receiver in it currently.

Also if you are going to be using a a go pro style camera on that plate that will counter your tail heaviness anyway to bring you back closer to correct cg.