Re: Re: F1D motor tube stiffness?

From: <ykleetx_at_gmail.com>
Date: 24 Feb 2014 10:26:06 -0800

Tapio,

 I have a couple of thoughts on your issue.
 

 You might try to set up your model with opposite wash, so that under high torque, the right wing does not have excessive washout. It's how Orsovai had set up his model for the mine for his 37+ min flight at last year's Otto Hints contest.
 

 To climb in a tight, controlled spiral, it is typical to use a large amount of left wing wash-in. In fact, I have been worried that my motor tubes are too stiff torsionally (I use .015" balsa), and I am going to build a couple of back-up motor sticks using .013" wood.
 

 There is another reason that your model might be experiencing right-wing tuck. It is that you don't have enough decalage. Under high tension and torsion, the motor stick bows and twists. Both forces will reduce the angle of attack of the right wing tip. Are you flying a new model that is either shorter or has a smaller stab? Or, have you moved the CG backwards? These would reduce your static stability and result in a trim with small decalage,
 

 I ask these questions because I believe it's rare to see the right wing tuck problem in F1D -- other than those caused by a loose joint or excessively weak wing or post.
 

 I hope this helps.
 

 -Kang
Received on Mon Feb 24 2014 - 10:26:07 CET