Bob G used to put zig zag ribbon the main wing of his planes just after the LE. Wouldn’t you want to place this about ½” after the LE? As the model is rotating the separation point changes correct? I would think you would want this just after the separation point in rotation as to help keep the air agitated during sharp angle of attack. But then again I have not seen this used on the stab, only on the wing. I will be interested to hear more about your findings. Dead calm days will tell you the most about what is actually happening.
I read the other thread.
There was talk of the “dead zone.” I don’t think there is a dead zone. Whatever position the elevator is holding is the ultimate direction the plane travels. The stab and elevator together make the entire rear airfoil. The elevator is always acting on the model. Our control systems are always under tension while in the air, even the loose ones with slop, like mine.
Droop is used in place of slop, or both are used as in my case. They both achieve the same effect. Think about the take off move with a drooping elevator. You must give it up to get it off the ground once it is rolling on the main gear. The plane is NOT flying with down elevator. It is actually flying with a tad bit of up or level elevator to hold the altitude. Level elevator on a slightly positive stab will create a camber on the top of the tail section this will create down force on the tail. Ted explained to me years ago that if you had a brick on the nose, moving the CG almost to the nose ring, it would require an enormous amount of constant up elevator just to get the plane off of the ground. And on the flip side with no brick on the nose the needed amount of input is minimal. But there is input needed because the CG is forward the aerodynamic center of lift for the entire model. Just because we are holding the handle level and the plane is flying level doesn’t mean there is NOT a constant small, micro, teeny tiny, amount of steady up elevator. The droop allows us to move the surfaces to the desired angles to create a camber in the main wing from the LE to the TE of the flap so there is actual lift AND it also creates camber on the tail section but the camber is on the top of the stab/elevator, whereas on the wing it is on the bottom. If the engine is at 0 or -.5-1 degree and flap is at 0 and the wing is at 0 the plane will not fly with down elevator. It’s impossible. Positive incidence in the stab with the elevators lined up with the stab gives you the exact same effect only a smaller amount of up is needed to due to the creation of the camber on the tail happens sooner once up elevator is applied to get the model off the ground. But the end result is exactly the same. I have been saying this for years but it doesn’t seem to get much traction. Direct side view pictures of stunt planes in level flight support this as well. It’s not always noticeable on the straight legs of a maneuver picture, but a picture of a model at level flight 4’-6’ with the camera at or about the same height it can be seen.
Topic: Zig Zag turbulators (Read 3952 times)