Flat vertical stab/rudder question.

[Fritter]

Thats what is in it right now (3MM), seems to be ok but I don't know much.
It's taken 2 of my friends that have been flying for years to get it going right- of course they own DA's and I will too as soon as this thing hiccups, stalls, sputters!

[rede2fly]

	Quote: Originally Posted by Fritter
	Thats what is in it right now (3MM), seems to be ok but I don't know much. It's taken 2 of my friends that have been flying for years to get it going right- of course they own DA's and I will too as soon as this thing hiccups, stalls, sputters!

would have been different if tom would have kept the dl line instead of going with the 3mm

[2walla]

Lets see some pics of this $189 machine..

[Fritter]

	Quote: Originally Posted by rede2fly
	would have been different if tom would have kept the dl line instead of going with the 3mm

From what I understand now, Tom has dropped 3MM because of production issues. If I had to do it over I would of gotten a DA. I do love the plane though.

[Paul5992]

I will post some pics tomorrow. Time for bed..........

[Paul5992]

Checkout post One...

87" Vertigo Edge 540


Here is an electric build thread...


http://www.rcgroups.com/forums/showthread.php?t=1084941

[Paul5992]

Were are all you smart mouth's now? I post pics and I still don't know any thing?

[yakpilot]

WTF? you're making a big deal out of a non-issue IMHO.

[sideshowbill13]

Heres mine!!! I just used a lot of glue on the rudder

[2walla]

Shoot that thing looks pretty good-- especially for the price..

[sideshowbill13]

Mines not finished yet i am just waiting to be able to fund the electronics and 52cc turnigy engine.

I plan on using it on imac once its ready!!!

Also been thinking about having the cowl airbrushed with flames to make it even more like the redbull 540 I like scale things.

[wingwall]

O.K., here goes. You should be fine, and it is good that the horizontal stab and elevator is an airfoil. It gives it some depth that contributes to stiffness. You need stiffness and little or no slop in your servo and linkage. Just don't do any full power dives. Thottle management is needed.

Many, if not most, airplanes, including ones with airfoils, can get flutter, it they go fast enough. It is vortex shedding that oscillates from one side of the elevator to the other at the rear that causes the flutter. If the sta/fin is not stiff enough (and strong enough) the oscilation of the vortex shedding can reach a resonant frequency that accelerates the deflection and force back and forth on the stab/fin. You either lose control or something breaks. It's the horizontal stab that usually needs to be stabilized and made stonger, particularly if it is flat and too thin. The fin is short and usually stiff enough with the fuselage to give it the strength and stiffness needed. As long as you keep the pull-pull wires reasonably tight it should be fine. (It appear from the pictures that you are using a pull-pull system.

I have seen ailerons of airfoiled wings flutter and come off, just because the linkage was not stiff enough. Flutter set in very noticebly on a Midwest Extra 300 ( 80" with a Moki 210) I had (still have) some years ago just on a very shallow dive at about half throttle. I tried to slow it down and get back to the field, but the aileron pulled out the hinges, yanked the single servo linkage apart, and the aileron fluttered to the ground. I was able to land with only one aileron. You usually cannot do that if you lose the elevators. With elevators in flutter you lose pitch control and crash. If you lose your rudder you can revert back to how most of us learned how to fly, that is with bank and yank flying.

The aileron was fine, so I glued it back in. The linkage and servo was another story. Gears got stripped in the servo. Since then I have gone to stronger servos and linkage. I don't know if the gears got stripped during the flutter or as the aileron came off putting a final pull on it.

The Midwest had truss wiring to stabilize the flat stab (older model), although that was not because it said so in the plans (kit built). I read about it as a good thing to do in threads such as this. Later models of the same kit had an airfoiled stab/elevator. The plane still had a flat fin. The rudder was not real strong on knife edge. That's where an airfoil would help also.

Have fun with it. And give us some feedback on how effective the rudder is.

W