CG On E-Flite Extra 300 1.3m
12-09-2019, 08:00 PM
#1
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CG On E-Flite Extra 300 1.3m
OK. So I just finished build and holy crap! The CG is way aft when the battery is placed in the compartment in the position indicated by the instructions.
By moving the battery all the way forward against the engine compartment, I managed to achieve the CG indicated in the attached photo. This is still aft of the recommended CG by about 6 mm (see photo).
It makes me think I have done something wrong, but I've seen comments about achieving correct CG by moving the battery forward as I have.
I can get the CG in range by adding an additional 60 grams in the nose, but it seems like I shouldn't have to.
I'm wondering if anyone else who has built this plane has encountered the same issues, and how they were resolved.
BTW, my installed battery in photo is 225 gram 4S.
Thanks!
(Well, I can't post my photo because I don't have 10 posts yet LOL. Just assume a photo exists of my CG aft of recommended range by 6mm)
By moving the battery all the way forward against the engine compartment, I managed to achieve the CG indicated in the attached photo. This is still aft of the recommended CG by about 6 mm (see photo).
It makes me think I have done something wrong, but I've seen comments about achieving correct CG by moving the battery forward as I have.
I can get the CG in range by adding an additional 60 grams in the nose, but it seems like I shouldn't have to.
I'm wondering if anyone else who has built this plane has encountered the same issues, and how they were resolved.
BTW, my installed battery in photo is 225 gram 4S.
Thanks!
(Well, I can't post my photo because I don't have 10 posts yet LOL. Just assume a photo exists of my CG aft of recommended range by 6mm)
12-10-2019, 04:19 AM
#2
My Feedback: (2)
First, welcome to the forum!
I have no experience with your particular plane, but I feel safe in sharing the fact that once past your maiden, where you CG is at, or needs to be, is up to you and the way the plane flies. Don't worry about where the instructions tell you to put it, that's only a suggestion to get you through a maiden safely. After that, put it where it needs to go to fly right! There are all kinds of tests that can be done in flight to give you some hints at where that might need to be.
I have no experience with your particular plane, but I feel safe in sharing the fact that once past your maiden, where you CG is at, or needs to be, is up to you and the way the plane flies. Don't worry about where the instructions tell you to put it, that's only a suggestion to get you through a maiden safely. After that, put it where it needs to go to fly right! There are all kinds of tests that can be done in flight to give you some hints at where that might need to be.
01-03-2020, 06:42 AM
#3
What size mAh is your battery? If it's 2200 that is on the lite end of the specs for this model. Maybe try a heavier 3200mAh battery and it would balance at the recommended spot. Then like ahicks said once you get past the maiden you could put the lighter battery in to move the CG back if needed. Just remember a nose heavy plane fly's poorly, and a tail heavy fly once. 
