Day 3 of Ground School – Controls and instruments – Part 11

I went to class on Saturday after a flight on Friday and I have to say things are making a bit more sense.

My flying skills are still garbage but at least the theories of flight and how a helicopter stays in the air is actually clicking.

We spoke about the collective for a while -which for some reason eluded me for more than it should have. Basically the collective changes the pitch angle of the main rotor “collectively”. Wiki explains it pretty well, “To increase or decrease overall lift requires that the controls alter the angle of attack for all blades collectively by equal amounts at the same time, resulting in ascent, descent, acceleration and deceleration.”

angle of attackTo really understand that you need to understand angle of attack, which luckily I do.  More details here:

Back to collective… on the collective there are some other components, a throttle – which is governed, a friction wheel, and the starter.  I never knew the throttle was governed and can’t imagine trying to fly a helicopter without it.  The throttle is a twist grip, it’s how you prime the engine(piston and carb) and warm it up.  It’s the opposite side from a motorcycle but you don’t seem to touch the throttle once you set it.  The governor does everything for you.  The friction wheel doesn’t do too much other than set the friction at which the collective  / throttle operate.

From the first day of class or first flight you hear about pulling power, its as simple as understanding that you pull up on the collective to go up and push down to go down.  The governor matches the throttle to keep the blades at an RPM it likes and voilà… (mostly) Flight!

I am ham-handed on this one, I yank on the collective whenever I feel a little worried about slamming into the earth.  I don’t know how to fix that yet.

So that’s collective.

Next up cyclic.

Cyclic controls the pitch angle of the blades – cyclically or depending on where they are as they spin around the hub. So every blade has the same incidence or angle at the same point in their rotation or cycle. Make sense? Yeah, it took me a while too. There is also this thing called gyroscopic precession but we’ll get into that unholy mess soon… In short, if you pull the cyclic left, the helicopter will roll left, push forward and the nose dips forward. I’m also ham-handing this one and it causes for the ugliest hovers known to man. There is this guy in my class that has it down already at 4 hours and I’m bummed I’m so far away… he probably played a bunch of video games and great hand/eye coordination.  I stopped playing video games when I had my kids 4 years ago.  I knew I shouldn’t have done that. (I mean stopped playing video games… I love my kids.(And my wife))

So that’s cyclic.  Now would be the perfect time to go into the components of the rotor but I’m going to grab some video of that to show what the hub, swash plate, etc…  looks like.  I’ll try to grab a pre-flight with Grant on Wednesday.

Next up pedals.

Md500Pedals or ant-torque pedals control the tail rotor if your helicopter has one.  Most do, except this badass MD500.  I’m going to have to talk my way into McDonnell Douglas to check one out.  That thing is outstanding in everyway possible.  I wonder if there are any in STL.

Anyway, pedals… they control the YAW of the aircraft, so which way your nose is pointed.  Push on one pedal and you go one way, push on the other and you go that way.  Not much to it other than I am beginning to understand that the Guimbal takes alot of pedal to get it where you need it to go.  I think the R22 and R44 take a little less but, each aircraft has it’s own quirks.  When you take off in the Guimbal you shift the cyclic a little to the right and you and input right pedal.

Pedals are the least complicated part in my opinion.

Trim!  I should mention trim.  We just got into in our last flight but it’s exactly what you think it is. You can make tiny corrections or “trim” out the helicopter to they flying conditions you’re currently in.  Those might be wind, weight distribution, etc..  I know it’s a big deal and I’m taking it for granted but if you need to straighten out the helicopter, a few clicks on the little hat on the cyclic and boom, you’re all cleaned up.

So that was a pretty long post on the controls.

I’ll follow up with what we learned about engine components and instruments.  We spoke about Manifold Air Pressure, Ignition (Mag / Plasma), Carbs, Gas, Magnetic Compass, Magnetic Variation, Pitot Tubes, Precession, VFR requirements and a few other odds and ends.  That will be a pretty long post as well… there is a ton of detail on each one of those items.