Nedcavak... I like that. Ned, nothing to be sad about, there is just a difference in opinion as to the description of a lomcevak. I'm not trying to ruffle any feathers; instead, I am attempting to provide information based on what I understand to be a lomcevak.

Twister... I never said models can't lomcevak, just that it is much more difficult for a model to lomcevak compared to a full size, so most models can't lomcevak. The smaller the plane, the less likely it can lomcevak. I've never heard any of those pilots say that models can't fly to the moon either... that doesn't mean models can fly to the moon.

Part of the problem is that the IAC doesn't have the lomcevak on the list of possible maneuvers, so many have come up with their own tumble and called it a lomcevak even if it doesn't meet the criteria of the maneuver. There is no governing body to enforce the lomcavak definition, but the important thing to note is that the definition still exists. So, how can we have multiple maneuvers all be the same thing? I have seen a dozen different descriptions of a main lomcevak here, everything from a end over end tumble to who knows what... that makes no sense.

All I am doing is regurtating info I have seen. A lomcevak is a gyroscopic maneuver. Scale is ALWAYS a factor. That's why we have reynolds numbers. With a full scale plane, prop mass compared to aerodynamic forces have a different ratio compared to a model. Models tend to have low mass props and they are flying with very different aerodynamic forces. The net result is that with models the aerodynamic forces greatly outweigh the rotational inertia of the prop, which makes precession in a tumble very unlikely because the aerodynamic forces will always win.

In the end I know I'm at the losing end of this dicussion because many will call any tumble a lomcevak and will continue to do so regardless. Hey, have fun, tumble your plane and if you want to call it a lomcevak, nedcavak or whatever that is fine, but it does creates confusion. 3D to a certain extent has that problem now. I have see three different maneuvers called a Heartattack... all were very different. Confusing.

For those that don't understand precession, please look at the first video I posted a few posts back. First there is the 45 up line. The a ~1-3/4 positive snap to the left, then full down elevator is applied to start the tumble. Note that the tumbles are end-over-end, and the flight path stays straight. Notice the actual orientation of the plane as it flips. It is always flipping end-over-end, but at one point the planes orientation is yawed 90 degrees with respect to the flight path. The nose of the plane is pointed straight up! It then rotates orientation on the next flip such that the plane swings back to normal. The reason why the end-over-end tumbles rotate orientation is due to rotational forces from the prop, i.e. gyroscopic precession. Remember, the plane is flying at basically zero airspeed, the control surfaces are basically useless once in the spin. The orientation chance is due precession. Spin a kids top, you can see the precession as the top handle slowly scribes out an ellipse.

Cheers!