Its going to be underpowered. It'll move sure but it's going to be underpowered by over 50% to the point where I can't really see it performing adequately, even if it is going to be flailing a mace. 3S LiPo (I assume that is what you are using given the voltage?) is definitely on the low end of the spectrum foir FW voltages, espeically when there is more weight to carry with an active weapon.