What can I expect from a gyro?

[cjcj1949]

I've been happy with my Futaba 401 and I've just bought an Assan GA250 which seems about the same. Very stable and ok for normal flying. I'm now starting to practice autos and after letting the heli drop using negative to keep the blades going I increase the pitch with power on to stabilise the altitude. When I do this the heli turns through up to 90 degrees. Do I need a better gyro or am I expecting too much? I am using a DS520 and the heli is a 450.

[Stanley Speel]

I would guess that the spinning is due to the very fast RPM change in the tail rotors. Remember that a tail gyro knows the heading of the heli. When you are autoing, the gyro has to make big pitch changes in the tail to keep the tail from drifting. When you flick out of TH the gyro is still making these big pitch changes, but they end up having more effect due to the increased tail rotor speed, causing the tail to turn.

I might be completely wrong but it sort of makes sense

[jimmyhorns]

As Stanley says, there is a huge torque input from applying power to the blades again, and the tail can only do so much at a given rpm...

I would think there are two things here (at least)

1) are your tail blade driven by the rotor when autoing?.. (if not then here may lie your issue, my hawks are NOT driven when autoing)

2) how far is your headspeed dropping when autoing?.. the closer you keep it to 'normal' the more efficient the tail rotors will work, and also the less torque will be applied when you flick out of throttle hold

possibly... is your gyro gain set correctly?... perhaps you could try with a little more gain and see what happens to the tail

[cjcj1949]

Thanks. Is it possible to keep the tail constant when coming out of an auto into powered flight or am I asking too much?

[jimmyhorns]

I would say yes, that is asking too much.... but then im not that experienced in this field... my autos end with a landing, one way or another

[cjcj1949]

Thanks. I'll stick with the current gyros then and not go for a Quark. I'll try using the controls to compensate.

[JoeBailey]

The main cause is letting the head speed bleed off to much. Try flicking into throttle hold and before the speed drops to low flick out and it should hold.

The lower the head speed the lower the tail holding capacity, the engine produces a huge amount of torque when dropping out of hold causing the spin. There should be a feature on your tx to slow the spin up slightly and reduce the kick aswell.


Joe

[Delarado]

ITs very hard on the tail.

the softer the start the more likely itll keep its heading.

If your just flicking out of TH into instant 70% throttle or whatever then your answer is no, its not possible to keep the heading constant

some ESCs have a bailout feature that does a semi soft start though to help with htis