Hello guest, if you read this it means you are not registered. Click here to register in a few simple steps, you will enjoy all features of our Forum.
This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
CG Center of Gravity
#1
Hello ! 
My question is..... Coming from a fixed wing background checking you CG was relatively simple. On a quad its a bit more tricky. What are some common methods to checking the CG on a quad copter ?  Popcorn
Reply
Login to remove this ad | Register Here
#2
I do this as simple as possible: hold the quad with 2 fingers at the middle of the bottom plate. Smile

While building i pretty much estimate which component has to go where to keep it even. In the end i try to keep some space to move the battery forth or back since it's the biggest, most compact piece of mass. If i'm lucky i only need to move it a few millimeters to get it right, and also if i'm having batteries with different weight i just memorize how much of a gap it needs between battery and the cam in front of it.
[-] The following 1 user Likes fftunes's post:
  • Lusetti
Reply
#3
And you can hold by opposing prop hubs to check vertical CG (with all cameras and battery installed).
[-] The following 1 user Likes sloscotty's post:
  • Lusetti
Reply
#4
I ordered a QAV-XS frame which little protrusions which makes testing COG easier. This was how I justified to you know who spending that $. But yes, this topic can be made as simple or complicated as you want. For instance, we're talking COG, but there's also COT (centre of thrust or thrust vector) to consider
[-] The following 1 user Likes RENOV8R's post:
  • Lusetti
Reply
#5
I check mine on a pencil on my desk. I set the quad on it and see how it balances. I typically just build with zero consideration (everything is pretty symmetrical) and let the battery take up the slack where it's needed.

That being said (I might be a little controversial here), I haven't found CG to be critical on any of my quads. As long as it's close enough, it will fly fine. The software is so advanced, it can almost account for the differences. My last flight out, my camera fell off in flight. It easily shifted the CG back an inch from centre. The quad got a little sloppy on flips, but that was it. For a drastic change in CG, it wasn't a drastic change in flight.
[-] The following 2 users Like Drross's post:
  • Carl.Vegas, Lusetti
Reply
#6
I don't think that's controversial at all!

As long as the COG is close enough, the flight controller will deal with any weight distribution issues. As a multirotor craft knows nothing about aerodynamics, having the COG at a specific point is largely irrelevant. As long as it's not taken to extremes, it's not that important.
[-] The following 3 users Like unseen's post:
  • Lusetti, hendrixhughes, Carl.Vegas
Reply
#7
I don't find it has to be crucially central and I often mount my batteries slightly closer to the front of the quad, feels a little better for fast forward flight imo
[-] The following 1 user Likes ZERONEST's post:
  • Lusetti
Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  QUAD CENTER OF GRAVITY hawk01 6 597 05-Apr-2023, 11:35 PM
Last Post: hawk01
  Solved Anti-gravity feature Krayon70 6 789 18-Feb-2022, 08:37 AM
Last Post: SnowLeopardFPV
  Does anything on a caddx vista have continuity with the center pin of the Ufl conecc epicjfpv 1 405 06-Feb-2022, 06:00 PM
Last Post: SnowLeopardFPV
  Jumper T-Lite.. gimbal dont return to center romangpro 4 1,724 19-Oct-2021, 08:59 PM
Last Post: romangpro
  Does the FC need be mounted at the center of the quad ? new2fpv 3 289 30-May-2021, 05:59 PM
Last Post: hugnosed_bat


Login to remove this ad | Register Here