ek4man

My Feedback: (24)

Hello. My trex 250 drifts slowly to the left I try to correct it from drifting left then it drifts to the right. I have an hitec hg 5000 gyro. I have the gain set at 75+ 75- on my dx7 radio. I am new to flying heli's, can fly around without crashing most of the time. I would like for someone to explain to me what rate and heading hold is ,and what is the function of both. Thanks Charlie.

Solman

Are you referring to the tail drifting?

BarracudaHockey

My Feedback: (11)

To answer your one question.

Rate mode is a gyro mode that dampens the rate (amount) of unwanted tail movement.

Heading hold mode is smarter, it not only stops a drift but applies a correction to get it back where it was.

If a helicopter is hovering with its side to the wind a rate mode gyro will sense the drift, correct to make it stop, and then recenter and it will drift again then the gyro will stop it over and over until the nose is into the wind. It will still turn into the wind but at a rate that is manageable by the pilot. (trust me it would be LOTS worse without one!)

A heading hold gyro will sense the drift and instantly correct it, if the wind gets stronger the gyro will apply more correction (as much as it needs right up to the mechanical limit of the tail pitch mechanisim if need be) until it stays put. Even in a changing sideways wind, a heading hold gyro should maintain the nose pointing in the same direction.

This can be clearly seen on the ground with the motor off. In rate mode if you move the rudder stick it will move then center. In heading hold mode it will move and stay there until the heading of the helicopter changes to where it was told to go. Since its sitting on the ground the gyro holds the pitch patiently waiting for it to respond. If you move the stick and hold it there for a few seconds the servo will pull the tail pitch until it cant move it any more.

BarracudaHockey

My Feedback: (11)

If you're talking about the nose staying put and the helicopter slipping sideways, thats normal, any helicopter with a tail rotor will do that even the real ones, when hovering with no wind, they lean to the right a bit (well most of our models do and anything with a clockwise main rotor does)

madmorgan

My Feedback: (2)

btw rate mode does not use the gyro at all usually the settings in your tx will be anything under 50 % this means and usually when u flip your tx gear toggle  down it is in rate mode provided you have it set at say 48 or 49 % the gyro does not control your tail servo so you must control it anything above 50 % this is heading hold mode and the gyro senses your nose postion and tries to hold it in the same position. ofcourse a few things have effect here. such as tail blade size tail shaft pinion size belt tension  wobble etc etc  all of mine creep just a bit ofcourse i wont go out and spend 400 dollars for a good futaba gyro and servo. i live with it

Solman

Your information is incorrect. As baracudaHockey said "Rate mode is a gyro mode that dampens the rate (amount) of unwanted tail movement. " So it is using the gyro, just dampens it. On my GY520, my gain is around 40, but is still heading hold mode. HH and rate mode isn't dependent on the number of gain, it is based on where you have the switch. Also a good futaba gyro and servo is not $400 escpecially for a 250 size heli. Also shaft pinion size would have nothing to do with the tail. That will affect your head speed. If you are running a super slow head speed, then yes it could affect your tail.

madmorgan

My Feedback: (2)

funny when i click my gear toggle from 0 to 1 my gyro light turns right off but no matter

Solman

Sounds like you are possibly using the GY401. On some gyro's the light turns off. On others they change colors. Either way, they are doing the same thing.

BarracudaHockey

My Feedback: (11)

The light goes off because the 401 is in rate mode. Check the manual that came with the gyro or download it at www.futabarc.com you will see what the light codes mean.

Pick up the heli and move the nose, you will see the servo correct, that means the gyro is indeed doing something.

Here's how gyro gain works in a nut shell.

Picture the gain on a rotary knob. If the knob is in the middle (50 on Spektrum radios but it varies depending on radio) then the gyro is off. Its in neither rate or heading hold mode.

Lets say Right is Heading Hold.

As you turn the knob to the right the gyro switches modes to HH and starts increasing gain. The farther you get from center the higher the gain until you reach full right where you're at 100 percent gain. Half way between center and right is 50 percent gain, in heading hold mode.

Turn the knob back to center and start moving it left and it switches to rate mode, as you move away from center you get more gain in rate mode until the knob stops and you're at 100 percent gain.

That all said, different radios display that to the user different ways depending on if you're using one of the gyro menus, or simply using end points on the gain channel. By using end points you're simply specifying where that knob stops.