General Autorotation questions

xokia

Active Member
I've never autorotated besides in the simulator. I think the simulator probably over simplifies things, way to easy in the simulator. So while building my 700 and seeing the size of the thing I figure its probably a good time to start learing how to autorotate. Now I'd like to learn how to do this before ever trying it on my 700. My 300x is out for learning on because it has no one way bearing. My next helicopter is the 450 pro dfc. Can this heli auto rotate reliably? Does it do it well? Things I should be concerned with?

I have always just held full negative pitch and then pushed the collective to positive pitch 10-15 feet off the ground. Am I doing this wrong?

I'm scared the damn thing is gonna fall like a rock lol!!
 
Last edited:
From speaking with the guys in the sim about auto rotation they had a few rather interesting responses.
I asked for the same reasons you're asking, I want to get something nice, and if i have to hit the oh crap button, I want to know how to get it down to earth in a few pieces as possible, hopefully one.
The guys will confirm how high you need to be in order to get autorotation to be effective, but generally they only said about 3degrees neg pitch and then flare it out and positive pitch as you get near the ground. As to exactly when etc that was very difficult to say.
I know I want to practice a bit with autorotation. I'm thinking that maybe I can throw some training gear on my 450 and practice that way, and hope that it works.
But i'm ahead of myself at the moment, I have to get mine up in the air first
 

coolgabsi

Super Mod & DEAL KING!
Hey bro .. To be honest. 450 is one of the worst sizes to autorotate. Its much harder and it needs extreme amounts of practice and timing to autorotate a 450. cause its light, the blades are small and the momentum is just not there so with the smallest amount of load, they slow down REALLY fast.. and stall.

Even a 500 is very iffy. MUCH practice needed. 550 onwards the disc is big enough to autorotate. I have honestly never pulled a good auto on a 450. My 450 pro had some crashes because i was being brave tryng to pull an auto ..

Autos are very simple:

The idea is that you hold some negative (NOT FULL NEGATIVE) .. like say how much you would use to hover a heli that size upside down. just under mid pitch. thats enough.. Your idea is not to push the heli towards the ground but to use that negative pitch to gain headspeed (windmilling) while heading INTO the wind (ALWAYS). Now depending on the size of the heli, your goal is to flare and use VERY LITTLE positive pitch. What do I mean by flare? :: THe heli is most likely travelling forward (if not push it a teeny teen. bit forward while giving negative pitch windmilling.. ) so when you are about 10 ft from the ground you very gently pull on the elevator stick so it will stop moving forward, and will convert that energy that it had moving forward and you will actually hear your blades pick up a bit of RPM by that flare. All that rpm is what ou are using to maintain lift. While flaring you would bring the collective very gently from negative to positive pitch, whip the tail around (if needed) and set the heli down slow and soft in an orientation you are confortable in.

You will hear me say :: SLOW .. gentle... teeny weeny a lot lol .. because any jerky or sudden movement in any direction will cause you to loose that energy that you are storing in the bldes to land.

So the bigger the bird and bigger the blades they will naturally wanna just hang in the air as the blades have significant weight and set it down.

I probably mkae it sound very complicated. but just remember, that too much negative will create a downward mementum in the heli's body and you will use most of your headpseed over taking that momentum and making it hover .. by the time that happens you are too low and out of time :D

700's are the best to learn autos on

how to start learning in real life: START small. MINI autos. that is any distance from 2ft off ground to say 5 ft off the ground.. past 5-6ft and till about 20 ft high is an unsage distance.. Its too low to gain rpm .. and too high to maintain headspeed after throttle hold.. So in the safe distance (say 6ft to .5 ft ) .. (approx numbers for a 700 size bird) .. you learn how to use your positive collective to gently bring the heli down. you dont have to use any negative at all. all you will be doing is hitting TH and then managing your collective all the way down and setting it where you want it to sit.

After you are fuly confident in that part. you have more than half of the work down.

Then the next step is to go high.. The higher you are the more time you have to gain energy and then hover at the end. so start with small ones. and then go past that unsafe window and use the hieight to your advantage. And yes its VERY VERY important to learn autos! :) ..

you can do small autos with the 450 too.. and you'll see what i was talking about.. you will have about 1ft -2ft off the ground ad any higher it will wanna fall like a rock..

One thing.. When I said push the nose down very little .. i mean very little. imagine the rotor as a solid disc.. for most lift you want the most surface area to be contact with the upcoming air (into the wind) .. and too sharp of a down ward angle and you will not feed the windmill enough air..

I explained in words.. it was the best i could lol.. but I recommend watching on youtube Curtis Youngblood's auto lesson .. or buy the vieo from smack talk. they are what explained and taught me autos. I still shiver when i take it high and hit TH.. but when it lands.. its an amazing feeling :D :D
 
Hmmm.... now i'm not sure I want to practice it on my 450... I was thinking that about the weight of them though....
Gaba perfect explanation!! love your work
 

xokia

Active Member
Thanks ill check out the smack talk vids. I do watch those I have not gotten to the autorotation one yet.
 

Tony

Staff member
You can do your beginning "cheater" auto's with the 450. Get it up about a foot off the ground, flip the T-Hold and start slowly adding collective. Once the skids touch the ground, go full negative to plant it. You can do this to about 3-4 feet up. Any higher, and the 450 will lose too much head speed. Just remember, from about 10' to 30' is the danger zone in autos. Not enough room to keep the blades spinning. And the sim is pretty close to what it is in real life. Although there is more wind in real life. Well, unless you are on my sim sessions lol. I put a LOT of wind into them.
 

xokia

Active Member
You can do your beginning "cheater" auto's with the 450. Get it up about a foot off the ground, flip the T-Hold and start slowly adding collective. Once the skids touch the ground, go full negative to plant it. You can do this to about 3-4 feet up. Any higher, and the 450 will lose too much head speed. Just remember, from about 10' to 30' is the danger zone in autos. Not enough room to keep the blades spinning. And the sim is pretty close to what it is in real life. Although there is more wind in real life. Well, unless you are on my sim sessions lol. I put a LOT of wind into them.

For me the sim seems WAY to easy. I can land an auto everytime in the sim you can almost auto anything in the sim. I can do inverted autos on the sim then flip it and land it. Not a chance I would try that in real life.

Getting a little bit of practice just by hitting throttle hold is a good idea and I will try that. Thinking of doing an auto on the 700 scares the crap out of me lol.
 

Lee

Well-Known Member
You can also practice the trajectory without cutting the motor. Take it high, point it in the direction you want to auto, then nose down slightly give a touch of neg pitch and glide it down to a position in front of you, give pos pitch and nose up were you can slow it down to a hover.
The first time you do it for real its scary as hell. But after a couple, you'll find its not actually that difficult.
 

Tony

Staff member
It's suggested that for the first few auto's that you over shoot your position going into the wind. This will put the helicopter tail in to you instead of side in.
 

Derek

Well-Known Member
You can also practice the trajectory without cutting the motor. Take it high, point it in the direction you want to auto, then nose down slightly give a touch of neg pitch and glide it down to a position in front of you, give pos pitch and nose up were you can slow it down to a hover.
The first time you do it for real its scary as hell. But after a couple, you'll find its not actually that difficult.

This is a great suggestion! As I am still working out the issues with the tail on my 500, I'm hoping to do some autorotations as well and doing an auto with the power still on, but the blade pitch in the negative a bit, would be really nice just in case you have to "bail out" of the auto or abort the auto.

- - - Updated - - -

It's suggested that for the first few auto's that you over shoot your position going into the wind. This will put the helicopter tail in to you instead of side in.

This is also a great tip! Overshooting your position, into the wind, and getting the orientation correct before landing. There is certainly no need to land the heli directly at your feet when you are just learning, lol.
 

stokke

Well-Known Member
I practice autos on my 450 - no problem. I practiced it a bunch of times on the sim first of course - then when I felt confident enough I tried it in real life.

When I started practicing in real life, I got A LOT of altitude then hit TH - auto'd maybe 20-30 feet, then hit TH and regained altitude again. In my experience, the 450 needed a bit more negative pith in real life than it did on my sim - but the concept of autos remained the same.

But the guys are right about the 450 being hard to auto with, it's got very little momentum on the blades - so the technique has to be performed right if it's going to work right. I'm still training, and have yet to auto all the way down to the ground.
 

Dirk

Member
Very interesting. I am nowhere near doing any autos yet, but it reminds me of the days when I flew Robinson R22 helis(full size)

From what I can see here it seems that a 450 heli = R22. Tricky and you only get one shot at it to do it right.
 
I would've thought most real heli's were you've only got one shot at getting the auto rotation right!!
I can with total confidence my pants would not be clean if I were in a helicopter and had to do an autorotation landing!
Don't care how big it is!
Now that I've said that, Dirk did you have to practice doing auto rotations do get your helicopter licence?
 

DAL2855

Banned
Yes Corsair, you do have to perform autos, not complete autos where you would actually cut the engine, but like for an R-22, the instructor would cut engine power to idle and expect you to land the helicopter properly!
 
Ok my level of respect for heli pilots just went up another level!!
that's nuts!! but i suppose sadly you have to train someway for when these things will happen, and need to know how it will feel when it does...
I can imagine it being a very eeery feeling not hearing any engine noises if you ever had to really autorotate down
 
I'll have to watch at home, stupid work internet is playing up.
I can only imagine!!
What an awesome experience, yet i think the first time terrifying experience...
Although the thought of having to do a unpowered landing of an ultralight doesn't scare me.... go figure lol
 
Top Bottom