15 May 2005

Motionless in Space!

Remember this?

http://www.compfused.com/directlink/114/

So, we'll agree you do need a little help to learn the skill!

If you've not yet done it, go now and read the earlier post "Pitchpull?" for the description of the controls!

The VERY hardest part of learning to fly a helicopter is learning to hover. Learn to hover, and the rest is downhill!

Most students take about 5 hours learning to keep the helicopter in one zip code!
The very best student I ever had hovered in 3.

A story to illustrate:
One of my friends was an airplane pilot, and a good one. He was also an A&P (Airframe and Powerplant) mechanic. After twisting wrenches on helicopters for a couple years, he knew the mechanicals of the helicopter as well as anyone possibly could. He figured since he knew the principles, and knew what the controls were all used for, he'd be a natural and just get in and fly off, right?

He laughs about it now: It took him 5 hours to learn to hover.

The machine is simply the most sensitive thing you will ever put your hands on!

I once tried to operate the controls of a backhoe. That came close to the degree of difficulty.
Patting your head with your left hand, rubbing your belly with your right, while riding a unicycle would also be a good approximation!

Once again, give me your imagination......
The engine is running. The main rotor is turning above your head. We increase the throttle until we are at normal operating R.P.M......
Center the cyclic.
Slowly increase the collective.
The helicopter will begin to get light on the skids.
Because of the increase in torque, the fuselage will try to turn to the right, so increase your left pedal pressure slightly to keep the nose stationary.
Continue slowly up with the Collective lever.
Depending on the center of gravity of the machine and wind direction and strength, it will probably tend to move laterally across the ground as it gets lighter and lighter on the skids.
Stop any lateral movement of the machine with Cyclic in the opposite direction of the drift.

Remember that so long as you increase Collective, you'll need to increase pressure on the left pedal to keep the nose straight.

We normally hover during training at about 5 feet, so when you reach this height, stop increasing the collective.

Now, stay there......motionless in space!

Only it won't happen like that! There's too much goin' on, and you'll be overwhelmed with stimulation!

I normally take students to a large field.......wide, flat, and unobstructed. I stabilize the bird in a hover, and give my students one control at a time.
"Put your left hand on the Collective".
It's the simplest of all the controls.......up Collective results in up helicopter, down Collective eventually gets the skids to touch the ground. Students get comfortable with the Collective quickly.

Then I have them release the Collective, and put their feet on the pedals.
At a hover, the pedals are also simple.....push right, and the nose of the machine turns right. Use less pressure to slow the turn.......even less and the turn stops. Push left to turn left. Push harder......turn faster.

It's not long until the student is comfortable with the pedals, also.

Now comes the TIGER!

The cyclic is so sensitive, if you watch a proficient helicopter pilot, you'll wonder if he's moving it at all. I can take off, fly a long cross country flight, and land, and not move the cyclic outside a one inch circle!

Students can't begin to do that. And therein lies the problem: new students overcontrol the machine when learning to hover.

INERTIA is the problem.

The helicopter begins to move in a direction you don't want it to go, so you apply opposite Cyclic to stop it.
Good!
The rotor instantly moves in the direction of your control input, but the mass of the helicopter takes a while to stop because of inertia. The student, sensing he hasn't put in enough control movement, puts in a little more.
Not Good!

About this time, the first movement takes effect and the machine stops, but now the additional control movement takes effect, and the machine starts moving in the opposite direction!

Remember, the student is trying like crazy to remain motionless, and right now he is using one control......the Cyclic!

Watching this lesson as a spectator is a riot.......you can tell when the instructor has the controls, and when he gives the controls to the student. The bird gets out of control pretty quickly with the student at the controls, and motion immediately stops when the instructor takes over!

At the end of the first period, I always allow the student to momentarily take all the controls, just for the emphasis that were I not along, the student would bend the machine in about 2 seconds!

Students walk away from the first hour sweating, tired, and respectful of all helicopter pilots, especially the instructor! Most of them are also bitten by the "hoverbug"......the desire to prove that they can eventually do it themselves!

Be ready........in a later post, we'll transition from hovering to flying.

3 comments:

denicave said...

Now I know why I get sick in helicoptors, hovercrafts and other things that act like a duck chasing a june bug!

OlePrairieDog said...

Hoo boy, does that ever bring back some exciting memories. I was watching a BMW commercial this week and saw some kids on a pier grab a guy by the arms and legs and go 1..2..3. ( the ad was for the BMW3 series) but I was transported back to the Holiday Inn in Miserable Gulch and the Solo dunks. That was the last time I was ever thrown into a pool. I think. Geez what a long time ago. I recall you were one of the first to Solo and I was one of the last. Course I had this way too big for the tiny machine problem.

Greybeard said...

To OPD:
Ahh, my old friend....
you'll be the source of many a post, if you continue to bring your comments!
The pool at Mineral Wells, with the crossed rotor blades leading to it! A fine memory!
GB