New story that I had forgotten about.
The Event,
I’m teaching this guy to hover. I like to hover about 2-3 feet off the ground. If you hover higher, it gets more squarely. If you hover lower, you will be hitting the ground all the time. (At least a student will) Because students are afraid of hitting the ground, they have a tendency to drift up into a high hover.
So this guy drifts up to 6-8 feet and I say “lower”. He continues to drift up to 10-12 feet and I repeat “lower”. This guy does not understand English so good and the intercom is kind of scratchy, so I figure he doesn’t get it. I yell “bring us down” while helping push the collective down. It doesnt go down and he is stone faced. I say “I have the controls” as we climb through 20 feet. I still can’t push the collective down and he appears to be frozen. Now I’m kind of pissed and I yell “I have the controls” and he says back “you have the controls”. But the collective still won’t go down.
At this point we are hovering at 30+ feet and still going up. Contrary to Hollywood, you really don’t hover that high unless you have a good reason. I dump the nose and get some airspeed. I’m on the right side and his collective is on his left, so I can’t see it. It won’t go down so I’m thinking he has frozen up on it. I yell “take your hand off the controls”. He holds both hands out where I can see them. The collective won’t go down. Houston, we have a problem.
Once I had a girl drop a camera under the collective and it interfered. I looked at my collective and there was nothing there. I told him to look under his and he said “no”. I said help me push the collective down. He was kind of freaking out and didn’t understand what I wanted. I’m pushing down on the collective with about 40 lbs. of force. It’s only a thin wall steel tube about 2 feet long. I’m scared that it might bend or break if I push any harder. Now we’re do 60 mph at 300 feet and still climbing. I don’t know what’s wrong and I don’t feel like sorting it out any higher.
Circle around and dive at about a 100 mph. The chopper goes go down at that speed. When I get to about 20 feet, I start to slow down. As it slows down, the MFer begins climbing again. This sucks.
The only other thing available to me to control power is the rotor rpm. The governor keeps it at 100%. I turn the governor off and lower rpm some, it will take some power out. The problem with this is you can only go a certain point and the blades will stall. If they stall, there is no speeding them back up. (The drag from stalling is more than the motor can overcome) On top of that, if you slow the rotors down when you are at a high forward speed, the helicopter will start vibrating like crazy.
So circle around again and dive at a 100 till I’m about 4 feet off the ground. As I slow down, I start twisting the throttle lower. I don’t dare go below 75%. I get the bird down to 2 feet and about 20 mph and I roll the throttle off. We skid to a stop.
The aftermath,
I shut it down with the collective stuck up. I tell him to get out and lift the seat so I can see the linkage underneath. As he is getting out, the collective goes down. I’m like WTF. We check out everything and all seems ok. I notice that his seat cushion is velcroed to the seat pan about 1/2” off center. It is off to the collective side, but it doesn’t interfere with it. I have him get in the seat while I watch. He has bad knees and has a difficult time getting in. As he gets in, he twists in a way that makes the seat pan slide over to the collective another 1/2”. It still doesn’t interfere, but when he puts his weight on the cushion, it squeezes the leather and cushion out the side a bit. When I pull the collective up, it just pushes the cushion out of the way. But when I go down with the collective, it wedges the leather and foam between the seat pan and collective.
I asked him how he didn’t see that when I told him to look and he said he didn’t know what I wanted. I moved the cushion to center and had him get in several times. All was fine.
Little details.