Ed

I have in my possesion a Futaba Gy - 240 gyro. Can it be used on the rudder of a model aircraft ? And if not, why not; please explain ? What might be the difference between controling yaw on an aircraft, as opposed to a heli ? Any special servo needs ?

Thanks.

> Jim

Hughes500E

My Feedback: (16)

The only reason that I think cancels your idea is that it would be a waste of a good Gyro! I say that only because the 240 is a heck of a rock solid performer in heading hold mode. In normal rate mode it will be as good as any, maybe a hair more reliable. I say this because you will want the gyro in heading hold mode but not all the time, you cannot switch into and and out of HH from the TX, like the 401 and the 351 etc etc.......
leaving the 240 in HH fulltime on an aircraft could proove to be fatle unlike a Heli.
Hope this helps somewhat!

Ed

I already own the gyro, so I don't consider it a waste, I'm not a heli guy here. And I've already flown with gyros on the rudder full time, and I have never found them a problem. Isn't the gyro overridden as soon as I move the rudder stick ? Not knowing much about this GY - 240, I'm assuming that when you say "normal rate mode", you mean that the AVCS feature is turned off. Is this correct ?

Thanks for your help.

> Jim

Phil Cole

That's right - you don't want to use AVCS mode on an aeroplane, except maybe when learning to hover.

The 240 does not have a rudder priority feature since it's an entry-level gyro designed for helicopter use. No rudder means that the gyro will try to correct any yaw that it detects, even yaw induced by deliberate rudder input. This is fine for the intended user (beginner helicopter flyers). Also, heli people can use AVCS which completely avoids the rudder priority problem.

Without remote gain control the other problem is that you can't compensate for changes in rudder effectiveness with airspeed. If you set the gain high enough to be useful when flying slowly or hovering, then most likely it will become unstable at higher speeds. Unstable means the tail will wag violently as the gyro overcorrects to one side then the other.

If you just want it to keep takeoffs straight then maybe you could use a separate steering servo.

Ed

No, yer don't understand. Just looking to keep a SLOW ground looping biplane straight on take-off. I have no intention of hovering a biplane, and to what I am observing, the rudder still works with the stick. I have done this before with cheap piezo gyros, but they turned out to be fragile and unreliable. So will the GY - 240 perfprm any differently then the cheap piezos if left in the circuit all of the time ?

> Jim

Bax

My Feedback: (11)

You can use almost any gyro as a yaw damper, regardless of whether it's an "airplane" or "heli" gyro. As a yaw damper, it will reduce the rate the affected control axis will move. This allows the modeler a better chance to keep it under control.

Heading-hold mode (AVCS with Futaba Gyros) on the rudder is not considered a good idea in airplanes because the rudder would fight the ailerons any time a turn was commanded unless rudder stick was also applied. Some people have used it for takeoffs, though, but turn it off as soon as the model lifts off.