peter84
07-27-2006, 11:15 AM
Here's what happened this morning.
Completed the range check on my Intrepid gasser, started the engine and let it idle for thirty seconds before preparing to lift off for the first flight of the day. Slowly raise the collective, looking for the heli to get light on it's skids when suddenly, the heli does a quick 180 on me and sits facing me with the blades still engaged. As I moved to the tail of the heli I am seeing no response to my radio commands - the main blades are spinning as the clutch is still engaged. As I watch the rotor disc is moving around the full extremes of the cyclic limits. I notice that the swash plate moving through the full cyclic limits about once every couple of seconds.
At this point I am ensuring that I and others are well clear of the heli. I tried turning off my TX to get the fail safe to engage, but to no avail. It was as though the power had been lost to the heli.
There I am standing helpless watching my pride and joy sit squirming on it's U/C, as I have about 4 degrees of negative pitch at bottom stick in normal mode, thinking this is going to be a long thirty minutes until the fuel runs out. At least it is a nice even engine note!
Thankfully fellow club member Wayne, found a 10' long 1" diameter piece of plastic water pipe in the club house (why do we have water pipe in the club house but no water....????). I was able to maneuver the pipe of the muffler exit and by blocked the end of the pipe with my thumb caused enough exhaust back pressure to finally kill the engine. By this time I was a so grateful to have stopped the engine without harm to anyone. The only damage, apart form my frayed nerves, was to the standard white tail blades that got chewed up when the hit the tail fin that had got pushed into the path of the blades when the heli landed after the 180.
So what was wrong? We had correctly deduced that the heli had lost power to the radio, what I found was that the radio switch (Hobbico heavy duty switch with only 12 flights on it - as this is a new heli) was in about mid position. I can only assume that I had not fully turned the switch on, hence the mid position, and that this was fine for a radio check but as soon as there was any sustained vibration - my 30 second run up, that the switch vibrated off.
So my question is; what alternative switch would you suggest and/or better operating procedures?
Completed the range check on my Intrepid gasser, started the engine and let it idle for thirty seconds before preparing to lift off for the first flight of the day. Slowly raise the collective, looking for the heli to get light on it's skids when suddenly, the heli does a quick 180 on me and sits facing me with the blades still engaged. As I moved to the tail of the heli I am seeing no response to my radio commands - the main blades are spinning as the clutch is still engaged. As I watch the rotor disc is moving around the full extremes of the cyclic limits. I notice that the swash plate moving through the full cyclic limits about once every couple of seconds.
At this point I am ensuring that I and others are well clear of the heli. I tried turning off my TX to get the fail safe to engage, but to no avail. It was as though the power had been lost to the heli.
There I am standing helpless watching my pride and joy sit squirming on it's U/C, as I have about 4 degrees of negative pitch at bottom stick in normal mode, thinking this is going to be a long thirty minutes until the fuel runs out. At least it is a nice even engine note!
Thankfully fellow club member Wayne, found a 10' long 1" diameter piece of plastic water pipe in the club house (why do we have water pipe in the club house but no water....????). I was able to maneuver the pipe of the muffler exit and by blocked the end of the pipe with my thumb caused enough exhaust back pressure to finally kill the engine. By this time I was a so grateful to have stopped the engine without harm to anyone. The only damage, apart form my frayed nerves, was to the standard white tail blades that got chewed up when the hit the tail fin that had got pushed into the path of the blades when the heli landed after the 180.
So what was wrong? We had correctly deduced that the heli had lost power to the radio, what I found was that the radio switch (Hobbico heavy duty switch with only 12 flights on it - as this is a new heli) was in about mid position. I can only assume that I had not fully turned the switch on, hence the mid position, and that this was fine for a radio check but as soon as there was any sustained vibration - my 30 second run up, that the switch vibrated off.
So my question is; what alternative switch would you suggest and/or better operating procedures?