I'm modifying a sophistocated lady (building the kit)... got any tips on my changes?

[e-sailpilot86]

I've got a carbon tail boom that I plan to install on the SL, and I'm wondering if I can move the tail-feather location back farther to my advantage. I tested the changes in a simulation program (lengthened tail boom), and the side-slip instability factor increased a little bit. Now, how much farther back could I move it, and get good results? I've also modified it so it's got a tail just like the Gentle Lady, and I'm considering extending the wing a little bit by making semi-cruciform wing tips. I want to clean up the airflow a bit, lighten it, and make it more of a charm to fly. BTW, the tail boom rod as of now is 35" long, and weighs almost an ounce.

[Ollie]

If you lengthen the tail moment arm a certain percentage then you can reduce the tail area by a corresponding percentage. The net benefit will be a small decrease in drag, no change in the static stability but an increase in pitch and yaw damping. The increase in damping will be noticable in that the plane will seem "groovier." The tail moment arm probably should not be lengthened at the expense of increased nose weight. Getting rid of the T-tail will save weight and make the tail more survivable in an abrupt arrival.

[John Gallagher]

The Sophistocated Lady wing is the same as the Gentle Lady. Since you are replacing the t-tail with the Gentle Lady tail, why do you need to increase the tail moment? Make the tail length the same as the GL. It should fly fine. How much are you adding to the wingspan? A few inches shouldn't matter.

John

[e-sailpilot86]

The area of the tail feathers is about the same, the only thing possibly decreased is the area of the vertical stabilizer. Not by much though, just a square inch or so. I don't need to increase the tail moment, It's just that the tube I have is so long, and a little pricey! I want to use as much of the $$ spent as possible. I'm guessing the tail feathers will be moved back no more than 5 inches, unless I "lengthen" the nose of the plane by sliding it a little forward more than usual. Most of the time designers don't make the nose long enough to compensate for the CG without much lead anyway...

The wing will be extended about five inches each side, just to clean up the airflow and reduce drag. BTW, I'm very happy (actually surprised) by the flying characteristics of the GL, I'm just making use of the stuff lying around in the garage!

(hey ollie, get an avatar!)

[Sparky Paul]

My follow-on fuselages for the GL are always 3 or so inches longer than the kit, to get rid of the ballast needed for the long (kit) tail.
I use the current version for AP, and it holds a heading nicely, doesn't require a lot of corrections, as does my SpiritElite.
Wouldn't change anything other than the nose length. The next version you might move more things around.

[Ollie]

e-sailpilot86,
Forgive my ignorance but, what is an avatar?

[e-sailpilot86]

It's the little picture underneath your screen name. :cool:

Sparky, I'm lost by what you mean by AP... :confused: sorry!

[e-sailpilot86]

Picture of GL fuselage with SL wing and carbon tail rod.

[Sparky Paul]

Originally posted by e-sailpilot86
It's the little picture underneath your screen name. :cool:

Sparky, I'm lost by what you mean by AP... :confused: sorry!
.
Aerial Photography...

[Brew Glider]

I have been flying my Lady for 12 years now. My mods were mainly from experiencing an overstresses electra wing. There was a several article set of mod instructions in I believe Model Avaition on the center wing. Anyway, I added a spruce spar across the now straightened center section. I still have the original breaks on the otter tips. I have never seen the center section flex when using this mod. I do have a stock wing as a back up that does flex quite a bit under high start shots.

Kepp it flying!:)