Sadler Vampire from Nitro Models
 

Sadler Vampire from Nitro Models question. Is the 3.5” recommended for the CG correct? In the manual they show two different ones (75mm= 3in or 90mm= 3.5in)don’t know which one to use.
Bobby V

RE: Sadler Vampire from Nitro Models
 

Either or anywhere in between.

As long as the plane sits with the nose gear on the ground ( once the batteries are in place ), it will fly.

The further back you put the C.G. the more responsive the tail will be up to the 3.5"-3.8" limit.

C.G.'s are really more of suggestion. I use the "that looks about right" rule and work from there.

Normally ( with exceptions ) if the plane balances at or in front of the wing bar/tube you should be alright.

Of course when in doubt the on-line C.G. calculators of of great help.

RE: Sadler Vampire from Nitro Models
 

Thank you very much for your response to my question. It was an interesting answer and I’ll be sure to apply it other’s that I plan on building. Thanks again.
Bobby V

RE: Sadler Vampire from Nitro Models
 

On most straight winged planes anywhere in front of 25% of the chord is perfectly safe.

For swept wing and bi-planes you want to have the C.G. forward of 25% of the mean chord length.

Many of my 3D planes go back as far as 30-40% but the latter can be iffy.

With the Vampire it is almost difficult to get the C.G. too far back if the plane sits level on the ground when ready to fly.

For it to sit level the C.G. has to be in front of the wing landing gear area, which is in turn also in front of the 25% chord mark.