piroette - nose pitches

[ewoodcox]

hey fellow freaks, I have a Align 3G on a SE, flies pretty nicely and all seems to work well except during piroettes. If I do a piorette I get a sharp pitch up and then pitch down and vice versa. I may be off on the directions but that is the behavior, anyone seen that happen and how does one 'fix it'?????

[Stevemech]

First thing to check is the cg of the heli, it won't piro level unless it's perfectly balanced, also the older gyros didn't piro very good .
Steve

[bad007]

Originally Posted by ewoodcox

hey fellow freaks, I have a Align 3G on a SE, flies pretty nicely and all seems to work well except during piroettes. If I do a piorette I get a sharp pitch up and then pitch down and vice versa. I may be off on the directions but that is the behavior, anyone seen that happen and how does one 'fix it'?????

Look real close at the tail box, tipped slightly will cause the tail to pitch up or down if tipped. If the main shaft is wondering the battery/ cog needs adjusted.
The swash not staying level will cause wobble.
Check your setup like this and if till stay level and then just adjust battery so the main shaft doesn't wonder. It will piro spot on.

[Generalx5]

Is your mounting surface parallel to the main rotor disk? It needs to be level. Or else when you give constant rudder, the unit picks up unwanted changes in more than 1 axis of its 3axis gyros. So you may be picking up some elevator axis changes when you piro. So then the unit gives elevator when you piro....

Which should explain why you get a nose up/ down.

Test by rudder left, notice direction of nose, then test rudder right, and note the direction of the nose. It should be opposite reaction. If that's the case, remount your 3G/3gx correctly.

Hope that helps.

[dwdw910]

I had this problem with my helicopter during Piro's as well. Your center of gravity is off. Think about the drive shaft as the middle of the see saw. Everything on opposite ends of it must be equal it weight, otherwise as the heli spin in piro- the computer will sense the inertia shift and attempt to correct it. The problem is that its parameters are not designed to fix it correctly. It sort of goes crazy and unpredictable. Either lose some weight or gain some weight to balance it out. All my CNC upgrades made my tail heavy so I had to actually add weights up front to balance it out. :-)