autorotation

[martnslater]

hi i am here again,
just a quick 1 , what exactly is autorotation ,is it something you learn or is it a way off getting out of a certain crash!!!, thanks again.
martyn

[ChrisB]

We dont mention autorotation on here,its a dirty word

[jimbob]

lol - an auto is a way of giving yourself enough lift to control your final descent with no engine power.

Put simply, you use -ve pitch during the heli falling with gravity to spin up the blades, and then use this stored energy at the last moment to slow your descent with +ve pitch.

This is a simplification, and its a little more complicated than this, but it tells you 'what' an auto is in its barest form.

Hope that helps.

[David Drew]

It's when the engine is cut, or cuts out, at height. The engine is not now turning the main rotors, so the heli drops. as it drops, the air spins the blades and keeps them rotating. Nearer the ground you use the rotating rotors to add pitch and slow the descent & hence land safely.

The tail rotorsa do not turn, so it's a controlled crash in a sort of way.

Most people are taught to do it purposely just in case it happens for real

I can only do it on the sim...I have never had the balls to try it for real

There is a technique - described on various websites, worth reading and understanding...just in case

David

[SRH990]

Its actually not as difficult as it seems, I spent hours practising on a sim (CSM v9 I seem to remember!) before I actually tried one then wondered what all the fuss was about!

Larger helis generally auto much better than smaller as they run longer blades, most 90's with decent blades auto very well, it's more difficult with 30 size helis as the blades are shorter and lighter and there is less energy stored in the blades, at the opposite extreme I've just started doing autos with my Mini Titan, not pretty, very little left at the bottom but down in one piece (I don't recommend learning auto's with a mini heli, Trex 450 or Mini Titan, you will spend lots on repairs!).

[simowill]

The tail rotorsa do not turn, so it's a controlled crash in a sort of way.

David

If your heli has a driven tail when auto-ing then youl'll still have tail control, if you dont then the heli will "weather vane" into the wind.

Its definately worth practising them as you never know when you might need to do it.

Plus there great fun.

Simon

[SRH990]

For years we didn't have driven tails, can't say I ever felt the loss With smaller helis a driven tail is a disadvantage as it saps some of the stored energy to keep it spinning.

[robgt]

You need a driven tail to perform acrobatic auto's though...
Cheers,
Rob

[moyesboy]

in an auto the heli is gliding in much the same way as a fixed wing aircraft can glide with the engine stopped.
Think of it as the rotors gliding round in circles.
The heli has a poor glide angle, in fact the heli can actually autoratate vertically downwards.

An autogyro is a constantly autorotating heli. Its rotors are not driven and it flies with a conventional engine/prop pulling it forwards.

In the same way as a glider can fly parallel with the ground with its speed reducing, a heli can hover for a few moments with the rotor slowing down and set down really nicely. This time is a few few seconds with a big heli, but a few fractions of a second with a small heli!

[Sesame]

does anyone want to run through the actual basics of how to do it, or does anyone know any good addresses where I can read up a tutorial, as ive tried to do it in a sim with spectacularly bad results lol

[jimbob]

Ok - well try like this for a start.
Firstly you need to have a channel set up for throttle hold on the sim that cuts the throttle but still allows you to use pitch.

So, climb to a resaonable height and with the heli pointing towards the point you want to land, hit the throttle hold.
Now smoothly and quickly advance the pitch to full -ve as the heli starts its descent (not a snap, but a quick move), and at the same time pitch the nose down slightly and 'glide' the heli towards the ground.
As the heli approaches the ground, pitch the nose up to achieve a 'flare'. This increases the air through the hopefully spinning blades, and slows forward movement.
At the same time, smoothly but not too slowly push in sufficient +ve pitch to float the heli to a hover or at least less of a crash, and land (as best as possible).

Repeat and repeat and repeat untill you can land every time!

Its harder on a sim than in reality I think, but its less painful to the pocket on the sim!

If i left anything out for an overview, please add comments.

[Smoothound]

I think full -ve is a little too much , mind you I guess it depends how you have your Hold pitch curve set...

[jimbob]

i reckon its a good start for a newbie - just to get max blade spin - its all about feel to get it right isn't it, but you cant really decribe 'feel' so I reckoned full -ve was a good starting point assuming not much -ve pitch on a newbie chopper....

[Sesame]

hmmm, thats the process ive been using obviously not correctly as ever ingle time on the sim I hit too hard it just dont seem to slow up, and wallop into the deck it goes.

obviously I need alot more practice, which is easy in pheonix as they have a auto training mode.

Thanks for the info though ill just keep going

[jimbob]

Its pretty much about timing the +ve pitch at the end.
Keep practicing - you'll get it...