Shinden got stability!

Feb. 06, 2007

Yesterday, Dave game me his j7w.xml that reflects the result of his experiments in flying Shinden. This flight dynamics model includes more accurate CG position and reduced effectiveness on the canard. I was excited to see how it flies, and found it very stable. He also told me that the command-line version of yasim tells us the position of the CG (Center of Gravity) in the aircraft so I can adjust the mass balance very easily. (Sorry, the command-line version of yasim is not included in FlightGear Mac OS X.) With the great info that he gave me, I modified the latest version with a simple CG equation to figure out the CG for the latest version (the latest version is a bit different from the previous one.)

CGoffset = D - (L * F) / W

where D = distance between nose tip and the main wheel, L = distance between the front wheel and the main wheel, F = weight of the front wheel, and W is the total weight of the aircraft. Assuming F = 1/6 to 1/8 of W gave me that the x-axis of CG comes around the leading edge of the main wing. The result of this computation was almost the same as the one he described in his xml file.

So I adjusted some other parameters to match the new CG point. Now the stable Shinden is available at J7W Shinden.

Have a interesting flight with this cute canard.