Giant scale Ultimate Biplane
 

I received the Giant Scale Ultimate last thursday and have been trying to finish it. The fuselage is way too tail heavy. According to the plane the CG is at 109.1mm from the front edge of the top wing. In order to get the plane to balance I will have to add 2.5lbs of lead to the nose, something is wrong. I am a 25 yrs plus expert builder and take my word for it that is way too much. I have placed all batteries and Ignition on the engine box and just have the rudder servo in the middle of the plane and the two elevator servos in the rear of the plane as per the planes. This is going to be too heavy to fly and the weight I need to add is more than half the weight of the motor itself. Will you contact me back to see about a call tag for this plane to get a credit. I can't keep this kit and risk crashing a $1500 setup. If you can please call me at 205-655-2848 during 9-6pm central.

RE: Giant scale Ultimate Biplane
 

What engine are you using?

I don't recall having to do anything more than putting the batteries on the engine box to get the plane to balance properly with a lighter ZDZ 50CC engine.

RE: Giant scale Ultimate Biplane
 

I just checked this, and you are using the C.G. for the 1.20 Biplane.

The C.G. for the 50CC Ultimate is approximately 1.5-2" in front of the rear top carbane mount.

What you are using would make the plane far too nose heavy and accounts for all of the added weight you believed you had to add.

You do not have to add the weight, which is also why I mentioned that I had no problem with it...


Not to sound disparaging, but I would have assumed that a 25 yr expert builder would have checked this first... I do so and I have far less experience than you.

C.G. calculators help a lot.

However if you've never worked with Biplanes this might not have been obvious.

If you've had other Ultimates, the C.G. tends to be in about the same rough position ( adjusting for the scale ) on all of them.

RE: Giant scale Ultimate Biplane
 

Magiccc,

Forgot that this calculator had Biplane calcs in it too!

http://www.ourdmac.com/files/CG_MAC_CALC.3.xls

Why not give it a try and see where it puts you! I never fly a new plane without running it through to check it out.

Credit goes to original poster!

MadDog Joe

RE: Giant scale Ultimate Biplane
 

Anybody have nay pictures of your Giant Ultimate 50cc from Nitroplanes? I'm thinking to buy one. Need coments.