I own an Extra 300 Goldbeg and I would like to know if it is possible to do a lomcevaks and how to do it.

Also, if anyone knows the gods and bads for this model.
Gilles

OH Boy,,, yeah you can do a maneuver that looks exactly like a lomcevak but its not aerodynamically the same by definition. There is no gyroscopic precession according to our resident astrophsysicists because the prop is too light,, but whatever...

Need to be aft on teh CG for it to work..

1. At about 3/4 throttle, Pull up on a 45 degree upline and roll onto knife edge canopy facing you. I prefer to do this from my right to my left across the sky...
2. On KE rapidly drive the sticks straight to the lower inside corners. (Chop Throttle, right rudder, left aileron, full up elevator... all at the same time))
3. The plane will start to tumble after about 1/2 a blink of your eye so at that point, continue to hold the sticks in to the center and push them straight up (full throttle, right rudder, left aileron, full down elevator.))

If you get the timing right the plane will suddenly snap end over end and finish with the plane upright flying backwards,,, tailfirst. About 3 revolutions is about as good as I can do... Even though you are finishing at full throttle the maneuver is so violent that the plane still come to a stop in the sky and fall out. SO you have to get off the throttle and then ease it back in as you roll it back into control and fly off.. Its a really cool looking maneuver even if it isnt a TEXTBOOK Lomcevak...

I tihnk that is a bad statement. Every gyro will have some amount of precession. Precession is how an axis drifts. Remeber as a kid you put a gyro on a string and its spinning axis would spin onthe string. This is precession. "University Physics" Ninth Edition Young and freedman. No whether it is noticable or usable on thsi scale is another story. Precession exists because there is no such thing as a perfect system. The mass of a gyro is not perfecty centered and evenly distributed. There is friction in gyros. Precession is a bad term to be used, you might mean the gyro scopic forces involved. Forces on a gyro also have the components of centripital accleration and tangential velocity. I know this is more than you wanted to know but I am almost done. For those of you with higher math skills the normal force on a gyro is the cross product between these to vectors. This is part of what causes the forces you see in flight. On a spinnign disc the force acts 90 degrees to where it is applied. Just because you prop does not weigh as much as a real Ex. 300 prop does not meanthe forces are not there.

so Cap-tainis that a proper lomcevak or not because Id love to try one, we dont see any lomcevaks at my field ever.

Here we go again. This subject seems to be timeless. It's been discussed over and over again in many threads. I know everyone has their own opinion about it. Lomcovaks (BTW that's how you spell it...translates as "shaker") in full size aerobats can be done in lots of different forms. Apart from 3 axis and throttle gyroscopic force becomes a 5th variable which gives you lots of possible variations of this maneuvre. The most common one is the conical lomcovak where plane spins in a conical motion. In models there doesn't seem to be enough gyroscopic pressesion to enter this maneuvre with authority. The only gyroscopic maneuvre,I know we do with our models, is torque rolling. I could be wrong there might be more but TR really stands out.
I don't want to start another war of words. I'm definetly not saying models can't do it but at the same time no one has ever showed me one.

Like I said,,, "but whatever"

do anyone have a video of LOMCEVAKS ????????

here is a couple of links
the first one is Yak 55 doing a climbing lomcovak. Unfortunately the video is half way through the maneuvre[link]http://www.yakuk.com/img/Lomcovak.mpeg[/link][link]http://www.yakuk.com/img/Evora1.MOV[/link]
the second one is Yak 50