Hi Mikey and Crist,
Thank you for your comments.
I am mounting the firewall about 7/8" AFT from the front end of the fuselage. The current width of firewall is slightly too large to push it in between the fuselage sides but I will shave it to fit. Before I epoxy the firewall, I will completely finish painting and covering the model's fuselage and tail surfaces. The current RTF weight is about 59 oz. and this includes: MVVS 8.0 (8 oz.), Igor's 12x5 N prop. (0.64 oz.), spinner and prop. adapter (1.0 oz), ThunderPower 6S 2800 mAh. (12.75 oz.), Spin66 ESC (2.1 oz.), carbon L.G with 2.25" wheels, tail L.G with wheel, all screws and washers, 1.0 oz. of wing weight and 2.3 oz. of painting and covering with Doculam.
I will find the required C.G for the RTF model moving the firewall with MVVS FWD and AFT. I know already that the 6S battery must be pushed as far AFT as possible and the available range of the firewall movement is 2.0" from the very front of the fuselage now.
Like I wrote, the plane will be tested also with other, lighter, motors with Plettenberg weighting 1.3 oz. less than MVVS. Because I am planning to experiment with 5S batteries having the same capacity like 6S and weighting, therefore, about 2 oz. less, the placement of the firewall must be carefully selected for all the motors and batteries combinations. My goal is to avoid adding the dead weight in the tail or nose area to get the C.G where it suppose to be.
I will consider doubling the thickness of firewall - the weight penalty is about 1/4 oz. for the second PCB piece and epoxy.
Happy Flying New Year,
M