Let me start this article by telling you that the sail winch in the RC Laser is the most reliable servo in the sailing industry. We have virtually no problems with this winch, none. I wish I could say the same for the steering servo.
However, I will tell you right up front, that rarely is the failure of the steering servo a warranty issue. In other words, it is almost always user error. Let me explain.
The Hitec 300 servo (steering servo) that we use in the RC Laser is the least expensive of the Hitec servos, and the most widely used of all Hitec electronics. This winch does everything we ask of it, as far as steering the RC Laser, so why would we spend more money to buy a more expensive winch?
The weak point in the servo is the gear set. The gears are nylon, and therefore subject to breaking if they are mishandled. But note – these gears are never broken while the boat is out sailing! Again, if the boat is out on the water doing its thing, the gears are not ever broken by the forces at work. So how do they get broken?
Model airplane flyers have a name for it – they call it “hanger rash”. It means that somehow the things are damaged when the equipment is out of its natural element and in the hands of someone on the ground, or ashore in our case. OK, I will quit beating around the bush and tell you specifically how it happens on an RC Laser.
Our steering system is very well engineered. The double SS rods are over kill actually, one rod would do just fine. But that is a good thing. What happens is that any force applied to the rudder is transmitted back through these rods to the servo, and if that force is a jolt, the rods transmit that jolt directly to the servo horn and the teeth start to fly inside the servo.
Specifically, there are two main accidents that cause a shot to the rudder that is sufficient to rip the teeth off your gears. The most innocent is the Stainless Steel cradle that we have. It is a nice cradle unless you put the boat in it so that more of the stern is hanging out than the bow. The cradle will not fall over at first, but any nudge, or wind gust, can cause the cradle to fall over backwards, landing on the rudder – and bingo, teeth start flying. So ALWAYS put your boat in the cradle with the bow hanging way out (keel all the way forward inside of the cradle). That way, the boat will only fall over forwards – which will cause absolutely no damage to anything.
The other method of eating teeth is careless handling. The recommended method of carrying the boat will avoid all accidental rudder strikes – trust me. Always pick up your boat by the leading edge of the keel, just below the hull. Turn the bow down facing the ground, mast out in front of you where you can see it. Your arm is straight down by your side grasping the keel as mentioned. Where is the rudder in this position? Yep, lying flat against your shoulder where it is well protected from strikes that could eat teeth.
One last note. When packing your boat for shipment, or a long trip in its bag, always be very careful to put the tiller hard over and then pack the area behind the boat with foam. This will keep the tiller hard over and prevent a sudden movement that could eat teeth.
How to test
And how do you know if you have already “eaten teeth” in your servo. The simple test is to grasp the rudder (with the radio and boat power off), and turn it gently from side to side. The resistence you feel and hear is the servo turning. If you feel/hear a skip, you have eaten some teeth.
OK, I think I done et some teeth!
Gear sets cost $5 and you can order from SailRCLaser.com. Opening the servo is not difficult and you can easily replace the gears in just a couple of minutes. To replace the servo itself costs about $14. A servo with metal teeth that would replace the Hitec 300 is about $35.
This article was written by Steve Lang of SailRC.com.