Wednesday, May 12, 2010
Learning to Hover
They call it, "Getting your hover button". Flying a helicopter is often described as patting your head, rubbing your belly, chewing bubble gum, and drinking coffee all at the same time.
Flying a helicopter consists of manipulating multiple controls all at the same time to cause the machine to do exactly as you wish.
The most important control is probably the cyclic stick. It comes up between your legs and controls the tilt of the tip path plane. When held perfectly neutral the thrust vector is straight up and you will remain over a single spot. Move the stick slightly forward and the thrust vector will be slightly forward and cause forward movement. If you let go of the cyclic stick the aircraft can easily tumble over and fall like a rock. This control has to always be under control either by autopilot or a human pilot. The cyclic is designed to be manipulated by the right hand. It is a delicate balance.
Next would be the collective stick. Adjusting it up or down either increases pitch or decreases pitch to the main rotor blades. Increasing pitch requires more power produced by more fuel. Decreasing pitch requires less power needing less fuel. In a turbine aircraft the fuel management is usually controlled automatically. In a reciprocating engine the amount of fuel is usually controlled by the pilot with a twist grip throttle. Such is the case with the TH-55 in the above video. If you increase pitch you have to increase throttle. If you decrease pitch you have to decrease throttle. If you increase the throttle too much there is a governor that kicks it back which is nicknamed "George". Without a governor you can easily over-speed the engine which causes other problems you don't want to deal with.
The collective which is controlled by the left hand is not as critical as the cyclic. In stabilized flight it can be fictioned down to mechanically hold its position allowing the pilot to free up his left hand to tune radios or do other chores. Because of this, the primary pilot's seat is the right seat in a helicopter which is just the opposite of an airplane where the primary pilot's seat is the left seat allowing the pilot's right hand to be available to tune radios and do other chores.
Then there are the tail rotor anti-torque pedals. If you increase pitch with the collective you have to increase left pedal in an American helicopter that has the main rotors turning in a clockwise direction. If you decrease pitch you have to apply right pedal. If the engine fails which involves a tremendous power reduction you have to apply right pedal ASAP or possibly go into a nose tuck that cannot be recovered from. If you fly a European helicopter where the blades turn clockwise application of the anti-torque pedals is just the opposite.
It is quite a challenge to learn how to manipulate all of these controls in unison for the beginning helicopter pilot. To find your hover button you have to be able to manipulate them all perfectly which is easier said than done.
But..., once you find your hover button you are well on your way to becoming a helicopter pilot and it all seems to come natural after that.
The next hardest thing after learning to hover was learning to fly with Night Vision Goggles (NVG), and then learning to longline. The first time I flew with NVG I wanted to yank them off and toss them out of the window. I wasn't the only pilot that had that feeling. NVG have improved quite a bit since the days I flew with them.
The very first lesson I ever learned in a helicopter though, was that I did not need to look at the person talking to me, e.g. my instructor pilot. There were plenty of other things I needed to focus my attention on rather than being polite and looking at the person talking to me. Looking at your instructor when he talked garnered a prompt rebuke, "Don't look at me! You have plenty of stuff you need to look at out there."
My very first instructor pilot was a man named Barny Ewell. He was very talented. I had two or three other primary instructor pilots, but the only other one I remember is Mr. Stan Gray who is also very talented and one of the best of the best of all the instructor pilots I remember.
Mr. Ewell took me out and helped me learn straight and level flight. He basically told me to pick a spot out in the distance and try to fly to it. A fixed wing bi-plan came alongside us while I was attempting to accomplish his request creating quite the memory. I later worked with a helicopter mechanic that was one of the original "Royal Guardsmen". Barry Winslow.
Mr. Gray helped me to get ready to solo and taught me some neat stuff to control my glide distance if I ever had a real engine failure.
In the middle an instructor I don't remember taught me to hover. He allowed me to manipulate only one control at a time until I seemed to get the hang of it.
The collective was first which controlled the height above the ground I maintained. The anti-torque pedals came next which controlled the direction the helicopter pointed. Then their was the cyclic...
I think the cyclic was the most difficult. It was very easy to over-control. You could get the aircraft moving back and forth like a pendulum by over-controlling the cyclic. Then if the instructor allowed you to manipulate all three: cyclic, collective, and anti-torque pedals you could easily find yourself going up and down and all around.
Then one magical day you found that hover button. Wow! The feeling is pretty much indescribable. When you could handle the throttle along with all the other controls you were close to being ready to solo. A change in any control affects all the other controls. If you move one, a movement in the others will be required. Eventually it all becomes second nature. It was fun too.
I sometimes think of different generations and eras. I love horses and there was the time of the cowboys.
Then there was Vietnam and the helicopter war with the time of the helicopter pilot:
I didn't personally make it to Vietnam, but I have sure enjoyed the heyday of helicopters. They are an amazing machine and pretty much as interesting as a horse to me.
I'll never forget finding that hover button and the men that helped me along my way...
ps. I think those involved with computers will be the new cowboys and helicopter pilots for the time we now know... What will be next? Who knows...