Safety Precautions & Reliability
updated 5-31-2007

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fail safe settings dx7 bind If you have a PCM receiver it is important that you set the failsafe so that the throttle will go to an idle instead of holding position. Some radios such as the Futaba 7C/9C have this as default but you still need to set the exact position for idle. <HERE> is a page on failsafe setups. On the Spektrum DX7 (and DX6) you need to bind the receiver again AFTER you have setup the throttle servo. When you bind a Spektrum receiver it looks at the throttle position during the bind and stores this as the failsafe position. So make sure the throttle stick is down and the trim is at an idle position.
DX7 capacitor If you are running several high current servos and the battery is low then you can experience moments of control loss. The reason is the voltage could dip below 3.3 volts and reset the receiver. The older technology 72Mhz receivers will also reset at 3.3V but you are less likely to see a problem because they do not have to scan for two frequencies on boot up. The time it takes to lock in is nearly instant most of the time but I have seen it take as much as a couple of seconds. To help prevent this you can add a capacitor parallel to the power lines. <HERE> is a link to the capacitor that Spektrum sells. It simply plugs into a spare channel on the receiver. If you do not have a spare plug like me then you could use a Y-harness. On mine I simply cut the wires coming from the power switch and soldered a 4700uf 10V capacitor to it.
<PICT 1> <PICT 2> <PICT 3>

tip submitted by Cleve Stuenhburg, thanks Cleve!

check bottom main shaft bolt regularly This bolt sees a lot of force from engine torque, crashes, and elongated holes in the auto hub sleeve/main shaft. Another problem is from the bolt having been tightened way too tight. Many new pilots see this bolt as well as the one going through the head block as the only thing holding the rotor head on so they get the idea that these need to be REALLY tight! In addition to causing other problems this also puts a lot of tension on the bolt. Instead you just need it a normal tightness. As you install the bolt when you feel the tension increase as the head of the bolt is now against the surface you then turn about 20 degrees more.
charger that tells how many ma put back in battery With a charge that tells how many milliamps it puts back in the battery you can observe the average you use per flight. If you fly four tanks then put a charge of 1000ma then you know you average 250ma per flight. Keep this number in mind each time you charge. If you see this increases (such as 3 flights for 1000ma) then you know something is wrong. Either you have a servo that is binding in flight or you have too much resistance in the control system.
checking battery immediately after flight The battery voltage will rise a few minutes after the flight so to get the most accurate reading from the battery you should check it right after the flight.
checking links for wear Check for worn links every so often. <This> animated gif image shows a very worn link. Also check the ball for a rough surface. The link can get dirt embeded in it and that will wear the ball down. You could find a new link fits just as loose as the old one. In this case change the ball and link both have to be changed.
tail link - servo eyelet In the picture you see a brass eyelet that comes with a servo has been cut in half and placed between the ball link and the head of the screw. Some have installed a washer between the two but I found that limited the pivoting range of the link. This is why I used the brass servo eyelet. As you see <here> the ball is worn out yet the link cannot come off. You do need a longer 2mm screw. <Pict3>
collar under top main shaft bearing This tip saved my heli once. If you have ever had the bottom main shaft bolt break on a R30/50 then you know this can be disastrous if it happens in the air. To prevent a crash just get a second main shaft collar just like the one that sits above the top main shaft bearing. Place the second one just below the bearing.
Check elevator A-arm pins From time to time I hear people say the pins come out in areas such as the head block, A-arms, mixing levers, and tail pitch fork. The reason is because of a tight fit on the end of the pins. For example on the A-arms the center section should hold the pin tight while the outside edges should freely pivot. I have seen people glue the pin in the holes of the A-arms! You should test fit the pins and if they do not rotate freely then use a drill bit that is smaller then the hole. Spin it around the inside of the hole and check the fit. Do a little at a time because if you grind away too much then you will add slop in the control system.
home made glow plug extention The glow plug extension was the highest maintenance item on my helicopter. However I have made one that has worked great. <HERE> is a description and pictures of what I made.