ORIGINAL: speedair
Hi ive got a black horse models chipmunk and im having problems balancing the plane. I have got an os 70 ultimate four stroke engine in the plane. The balance point by the manual is 100mm from the leading edge of the wing. when i tried this the plane was so tail heavy i couldent get the tail off even with the battery and all my gear as far forward as i can get. i tried 8 oz of lead and still cant get the weight forward. Any sugestions would be gratefull
I don't know this model at all so anything I suggest is "generic".
One thing you could do that would be helpful is measure the chord at the wing root and the chord at the wing tip. Where does the manual say to measure the CG position? At the fuselage?
Check that the engine is far enough forward. You should fit the engine to suit the cowl on a scale model, not the other way round.
Make sure the wheels are in the correct position.
Bring any tail servos forward into the fuselage.
Review the tailwheel weight and consider a non-scale skid.
Remove any pilot figure in the rear seat.
Add a pilot figure to the front seat.
Use carbon rods in the wing servos.
Fit an alloy spinner.
use a spinner weight (Harry Higley?)
Use an in-cowl silencer.
Add doublers to the fuselage skin in the forward section (if you need forwards weight, you might as well make the thing stronger)
Bring the battery forwards into the engine bay, and use thicker leads.
Invest in an on-board glow system and fit it forwards.
Visit the fishing tackle shop and buy some lead!
That's about exhausted my to-do list.
'Hope some of it was helpful.
Carole Sherrington