My Pick for the 1997 Product of the Year Many of you have probably realized by now I'm pretty "efficient" when it comes to buying stuff for my choppers. I like to get every last cent out of each item I invest in. So it probably came as a big surprise that I dug deep in to my cobweb infested wallet to pull out the bucks to invest in a new gyro, especially after having just invested in the then new JR 900 piezo gyro. That alone would be enough endorsement for the new CSM ICG360 Heading Lock System for most but in case you're not convinced let me tell you what has me so excited about this gyro.
First, say good bye forever to tail rotor compensation mixing. For those of you just starting up with helicopters, tail rotor mixing is needed to add tail rotor control input to compensate the change in torque when increasing or decreasing collective pitch. Getting that perfect mix to keep the helicopter from rotating when you climb or go to full forward flight can be next to impossible, which, at least in my case, leads to "flying the tail" a bit to correct the mismatch in mixing. With the CSM gyro --- no mixing needed. Lets take a look at why.
A normal gyro works by sensing the rotation of the helicopter about the main shaft, either using a small rotating flywheel (mechanical gyro) or a special crystal that is sensitive to rotational stress (piezo gyro). If the helicopter tends to rotate clockwise the gyro sends a signal to the tail rotor servo to rotate clockwise to stop the rotation and hold the tail rotor position. Unfortunately when you want the tail to move you will have to overcome the resistance of the gyro to that rotation. Some have devised schemes that reduce the effectiveness of the gyro in proportion to that amount the tail rotor stick is pushed (stick priority), so when you want to rotate hard, the gyro is essentially turned off. However flying fast sideways with lots of tail input would be without gyro. This scheme does work pretty well and I was quite happy with it in my Futura with the JR 900 gyro. I've often asked myself...why do we have to go through all this trouble???
With the CSM you don't....that's why I'm excited! The CSM is different from other gyros in that it directly controls the tailrotor servo. You are just telling the gyro what direction you want it to point to and it keeps the heli pointing that direction..."heading lock" ... get it? The CSM gyro controls the total tail rotor throw so you need to mechanically adjust you servo wheel and tail bell crank to match the gyro throw. Next disable all tail mixing and zero all the tail trims in the radio. Once done, there are only two simple radio adjustments to make to dial in the response.
First, since you tell the gyro what direction to point, you'll need to define how fast you want the gyro to instruct the servo/tail pitch to rotate the helicopter to get to that direction (yaw rate). This is done by changing the tail rotor servo end point adjustment in the radio. Remember, this doesn't change the tail rotor throw (the gyro fixes this) but changes the yaw rate. This is quite different than normal gyros. Just keep bumping up the end point value until you get the rotation you want at full stick deflection (for example in a 540 stall turn or a hovering pirouette).
Second, you need to adjust how strongly the gyro will hold the heading. This requires a separate gyro gain channel in your radio/receiver. Simply bump up the end point value of this channel until the tail starts to wag in flight, then back off until it just stops. I've heard that if the gyro still won't hold heading at this point, you either need longer tail rotor blades or a faster tail rotor speed.
All that said, how's it fly? FANTASTIC! Even though I've only had a few flights on the new gyro, already it's proving a great investment. I have had to undue some bad habits as before I had to "fly the tail" to over come my mismatched mixing which with the CSM caused me to crab across the sky. After tweaking the radio adjustments a few times, the yaw rate and direction hold were optimized to my satisfaction and a few tricks show the holding power of the CSM. Sideways flight at a pretty good clip was not a big problem with no tail rotor input! My favorite, and it really did freak me out at first, is a half stall turn where you just let the helicopter fall on its tail. My Futura had no tendency to weather vane around and did fall straight backwards down. Needless to say, as my shorts loaded up, I pulled out of it quickly.
With simple setup and awesome performance, the CSM ICG360 Heading Lock System gets my Product of the Year for 1997. For those of you who prefer a conventional gyro, ICG360 does have a standard mode but I can't think of a single reason to use it, even for the novice. Highly recommended for all levels of flyers. John Anast