Gyro Programming 101

Dec 12, 2013 No Comments by

Many low-time heli flyers making the step from Bind-N-Fly micros to larger helis struggle with programming heading hold gyros. The following is a general guide for programming gyros. It’s not intended to address the much more aggressive setups needed for full-on 3D, rather the goal is to program a typical gyro for sport flying.

Because my interests run to sport acro and scale flying, my gyro setups are conservative. I’m not doing high-speed tail first flight, so my goal is reasonable hold and minimal tail kick with rapid collective inputs. That said, here’s my general procedure for programming a typical heading hold gyro:

  • 1. Set gyro gain on transmitter to −40% on heading hold setting and +40% on rate setting. These are starting points (Note: Some makes of transmitters use positive numbers for HH and negative for rate—check your manual).
  • 2. Set gyro to analog or digital depending on your servo (this is becoming less common now that digital tail servos are almost universal).
  • 3. Hook up gyro and servo in rate mode and check for centering of tail rotor.
  • 4. Check servo travel with rudder stick and reverse on transmitter if needed.
  • 5. Check gyro correction by swinging tail and reverse on gyro if needed.
  • 6. Adjust travel on gyro so that pitch slider has full travel and no binding. If necessary, move servo on tail boom to get full travel to both endpoints.
  • 7. Test fly and adjust gain/delay settings to eliminate tail wag. Many 3D flyers start with very high gain settings and gradually reduce the gain until tail wag disappears. I prefer to start with a low gain setting and increase it only until I get an acceptable level of hold on hard pop-ups.
  • 8. Continue flight testing, focusing on piro rate. Adjust rudder travel to fine-tune piro rate in both directions.

Some gyros like the ubiquitous Futaba GY401 have separate adjustments for gain and delay, and this is a useful feature. Simply stated, delay sets speed of gyro response, while gain sets amplitude of response. I think this makes setup easier, but with many gyros, you’re limited to adjusting travel and gain. The problem there is that restricting travel to cure tail wag will also limit the piro rate. There are some very inexpensive gyros on the market, but even these days you tend to get what you paid for.

Helicopters, Jim Ryan

About the author

A longtime contributor and the current "Heli Talk" columnist for Electric Flight, Jim has been heavily into aeromodeling for nearly 25 years. Electric warbirds are his main love, although in recent years helicopters have taken much of his attention. He is focused on scale helis and his favorite part of the hobby remains designing and scratch building.
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