MGJ01

Hi guys,

I have acquired a Blackhorse Travel Air model (link below) and I am having issues achieving the recommended CG without adding weight to the nose. The manual states CG to be set at 72mm back from the leading edge.

Traver Air | Blackhorsemodel

The engine is a .46 ASP 2 stroke nitro. Its got Hitec HS-425BB servos on all surfaces. The tank and battery are at the most forward position.

As is currently is, it requires approx. 160grams of lead in the front to balance. Has anyone had any experience with balancing this model?

Could it possible that the CG has been mis-printed in the manual.

All Day Dan

My Feedback: (5)

It looks like that model has a constant chord wing. If that is the case, the correct position of the CG is 30% of the chord behind the leading edge of the wing. Include the ailerons when determining the length of the chord. Dan.

MGJ01

Thanks for the reply

Yes, the model does have a constant wing cord, measuring 270mm from the leading edge including the ailerons. 30% brings it to 81mm from the leading edge, which is still tail heavy, however it doesn't require much weight up front to balance.

Maybe a different spinner or prop nut will help get it level.

Do I keep the balance point at 72mm or 81mm? How will this affect its flying characteristics?

All Day Dan

My Feedback: (5)

The 72mm point is at 27% of the Mean Aerodynamic Chord which is close to the 30% point I mentioned. I would use the recommended value of 27% from the manufacture. At that point the model is a little more nose heavy which would increase the model's stability. They have performed flight tests and would know the best point for success. We all suffer with ballast. A spinner will help a little but don't load up the crankshaft too much. Don't forget to measure to measure the CG around the length of the fuselage. You want the wing to be absolutely level or you are going to have trouble trimming the model. Dan

All Day Dan

My Feedback: (5)

It's called the longitudinal or roll axis. Dan