Big feet

Hi all,
Well, I finally did it, a controlled auto. My first attempt a month ago was more of a 'drop like a stone' auto. My head speed was too low.
Granted it was only from about 4 feet up, but it still felt great.
After about 6 of them I was low on fuel and had to land as the autos were late in the flight.
I do have a quick question.
How do I proceed now? Should I take the plunge and do one from 40 feet or increase height slowly??
I have been doing autos on the sim (G3.5) for months now and have no problems. But this is real life (money) now.

BTW, thanks Barracuda for the advice on blades. I put a set of SAB 620's on to learn autos.

BarracudaHockey

My Feedback: (11)

40 feet is easier than 10 or 15, it gives you some time to think and set up.

Every auto is different, it takes practice to get the feel for whats going on and make it do what you want vice being along for the ride.

I dont have any reviews on the bench right now so I may take the time to do an article with some video and stills and stick it in the magazine section.

Big feet

That would be a good item for us beginners to autos.

So is 10 - 15 ft the most difficult height to do a successful auto from?

Crazy Geezer

I did my first auto the other day, first did it from a hover about 2-3 metres up facing away from me, i thought, pfft why not!, flicked the switch, brought it down like i would with the engine on, then the 2nd time around, did it nose in! hell yeah!!,,

was just wondering, i could setup another condition on my 9zap for autos, so that, i flick the switch, engine comes to idle, pitch range is set up for optimal autorotation etc etc

How much negative pitch is optimal to keep a good headspeed up??

mxracerx43

I also installed the red gear that gives you a non driven tail. Kepps alot more inertia in the blades With a decent head wind and this gear I can throw in a whole pirouette after the flair and land nice and soft. Also make sure you are gong into the wind. I was helping a friend learn and he did much better with a decent wind blowing pretty constant one direction, just make sure you are ready to flip hold and bail if you have to.

archiebald

Big Feet,
full size heli pilots have what is called a "Dead man's curve". What it boils down to is the speed and altitude relationship. Or, more practically;

Low = Easy
High = Easy
Medium = You're dead

Forward speed (or a headwind) will always improve your chances at all altitudes.

After you have mastered "baby autos" from less than 2 or 3 meters, you need to "go upstairs" to at least 30 meters or more. Try visualizing a virtual ground level about 5 or 10 meters up and auto down onto that, then switch off the throttle hold and go around. Be ready for the tail to kick around when the power comes back on. Keep doing this but make your virtual ground level lower and lower until - WOW!!!! I did it!!

It is not that difficult really, just need to steady the nerves. And, even if you do stuff it up, very little damage is the normal result because most of the damaging energy comes from the rotors. When you are at the bottom of an auto, most of that is gone.

Crazy Geezer,
You probably already have a pitch curve set up and you don't know it. I don't know the 9Z but the 9C (and I think virtually every heli or computer radio out there) has a dedicated pitch curve for HOLD mode that comes in as soon as you flick into throttle hold.

As to what is the best, that depends on the conditions so you don't want to restrict yourself. Personally I use everything I can get out of the Raptor from around -10 to +11 degrees and more positive if you can get it, but I don't necessarily use all that on every auto. You just have to watch the heli's downward glide and head speed and keep compensating as necessary.

Mxracerx43,
I guess its personal but I prefer to have tail authority during an auto so I'll stick to a driven tail.

USMC2111

Yes and no. It is a level in which you do not want to do an auto. From a few feet up, when you flip the switch, you still have the headspeed from when the engine was powering it to make a successful auto. From 30+ feet up, you first loose headspeed but quickly regain it during decent with the proper amount of negative pitch. If you do an auto from 10-15 feet, you lose the headspeed and you dont have enough time while dropping to regain it back. So you end up hitting the ground hard, usually bending the spindle and possibly a boom strike.

If you take the plunge to do an auto from up high, remember that forward momentum is your friend. You dont want to go right above yourself and hit the hold switch. Just like archiebald said, you want forward speed. Set up at 35- 45 degrees from yourself with heli facing into the wind. Fly forward and then give about -6 degrees negative pitch. As soon as you give the negative pitch, flip the throttle hold switch. Keep it in the negative until you are about 6 feet off the ground, still moving forward. Now is the time to start flaring. Add + pitch little by little until you settle down to a nice landing. Remember to try to land on the front of the skids. If you land on the back you risk a boom strike.

Big feet

Thanks guys,
I will give it a go next time out.
And I will let you know the outcome, good or bad.

<GULP>

BarracudaHockey

My Feedback: (11)

Its harder to make yourself flip the switch than do the auto, but its better to do it when you are expecting it than when you have no choice.

When I teach someone how to do it there's a few things I start out with.
1. Tighten up the blades in the grips.
2. Bump up the throttle hold point so where the engine is spinning the blades at a bit of a fast idle.
3. Pick a day with a fair but steady breeze, airspeed is your friend and in a 10 knot wind your airspeed is good w/o your ground speed getting out of hand.

Visualize a right triangle. Lets say 50 feet downwind and 50 feet up, medium forward speed, into the wind.

When you hit the point of the triangle hit throttle hold, give negative pitch as you hit the switch. Every helicopter has a point that is a perfect auto descent. It depends on the weight of the helicopter and the weight and design of the blades. Above that point and headspeed decays prematurely (a bad thing!), past that point and the helicopter drops faster without the faster drop increasing the head speed. -3 or 4 to -6, somewhere in that range.

You want to descend nose level (yep) at a 45 degree angle, if you do it right the top leg of the triangle will end right infront of you, though it may be best to pass yourself by about 10 feet so you're landing tail in the first few times.

At 10 to 12 feet feed in a little back cyclic to arrest your forward speed (no need to stand on the tail, just ease back) as your speed decays you start feeding in collective pitch. You should have a feel for this from your baby autos but things will be happening faster. Dont "pop" the pitch, you should be at about 2 or 3 degrees as you pass 5 feet with your forward speed almost 0. After that its a matter of feathering the collective for a nice smooth touch down. As you get under a foot give a very slight amount of forward cyclic as you touch down, this will keep the tail boom and the blades apart if you bounce

I had a guy I've been working with say "wow I'm not even using all my collective now"

Every auto is different, you have to assess your entry and know whether or not you botched it. You have to know when to hold up and know when to fold up so to speak. The 9C has a delay adjustment, I set it to 20 percent for pitch and throttle so you get a smooth ramp up if you have to bail.

Lower the throttle hold a little each time you do a good auto to keep from using it as a crutch until its at idle.

Big feet

Thanks BH, all good stuff.
I saw you mention the high throttle hold in another thread and will give that a go.
Like most things in life, i have watched other people do autos, and read about them, but 'doing' them will be another matter.
Would there be any benefit in editing the weight of one of the models in the sim and makeing it heaver to make the practice harder??

Cheers,

Oh yeah, I'm using a 9X2 (9303 in the US) and have set my throttle hold release to 0.75 seconds to help save the heli when I bail out.
Note, I said 'when I bail out'. Realist me.

BarracudaHockey

My Feedback: (11)

Lighten the blades

Big feet

OK, thanks.

badazzbusa

My Feedback: (1)

If you bail, don't stab the throttle. Just flip the switch and let the engine pick back up before you add collective.
Also, you will see as you give neg. collective the heli is going to settle nicely as you come in and it will take very little cyclic control as you land. It takes alot less control than a landing under power.

Flying Geezer

My Feedback: (14)

I'm watchin' this with helicidal thoughts.

BarracudaHockey

My Feedback: (11)

Like I said, its better to learn BEFORE you need them than be falling like a rock wishing you'd learned them.

When you start flying around is the time to get started working on them.

One of my students I kept harping at and he finally sat down and spent a day learning. He was out at the field during that week one night and his engine cut and he thanked me profusely that night for getting on to him.

Flying Geezer

My Feedback: (14)

On "NORMAL" I have 4 degrees negative. Is this enough to spin it up, or do I need to be in idle-up?

badazzbusa

My Feedback: (1)

What radio do you have. I have a 9c and regardless of the mode your in, throttle hold has it's own pitch curve. Check and make sure you set up a pitch curve or see what your radio has before doing autos. You should be able to setup throttle hold just like any other flight mode, the throttle hold switch will over-ride whatever other mode you are in.

Flying Geezer

My Feedback: (14)

Thanks. I didn't know throttle hold had a curve. I also have a 9C, so i'll program throttle hold. Maybe +10 / -6 ?

badazzbusa

My Feedback: (1)

Some people shoot for more + on the throttle hold. I only have +11 on my 50's, same as every other mode, and it is plenty. -6 is fine, Mine is -11 and I only go back between 1/4 and 1/2 stick on a auto. The main thing (my opinion) is make sure the upper 1/2 of the curve matches your flight mode curve so when you flip the switch the swash doesn't move. If you flip the switch and the heli pops up, you just lost all your head speed. Up high you can recover but if your ever low and flip it your screwed (trust me). Once I had just fixed up my 50, forgot to redo the pitch curves in throttle hold. Started the heli, hovered, checked the tracking, hit the hold switch at about 5 feet, it popped up 5 more feet and all I could do was say s--t! The fuel in the header tank lasted longer than that set of blades.

Big feet

DONE IT,
My first high auto.
I did a few low ones last night just to get my head in gear then went upstairs and hit the switch.
My Rappy settled into a nice, but slowish, decent and I had plenty of energy to slow and flare at the bottom.
I wanna do more.
Rain stopped play, but then again, theres tonight.

Thanks for all the info guys, really appreachate it.

Peter

BarracudaHockey

My Feedback: (11)

Nice job!

Geezer, I can't really add to what Bad told you.

archiebald

Big Feet,
TOLD YOU!!!!! Nothing to worry about eh?

It^s a great feeling when you complete your first one and it brings you more into the comfort zone when you are flying. You KNOW that you CAN get her down in one piece if you suffer a flame-out.

Patto

My first auto, away from the sim, was when the fuel hose came off about 40 feet in the air and the engine revved and quit unexpectedly. My Raptor 50 came down fast and I hit full collective just above the ground in idle 2, which slowed the decent and it bounced just a little bit, no damage. I've practiced since then from heights of about 10-15 feet and it seems to have so little energy in the blades that I'm afraid to try it from higher up.

I'm just using the standard 600mm wood blades, however, and I imagine it would be improved if I used some decent carbons. The only problem is how expensive the carbons are, unless you get the standard Maveriks, which people don't seem to like very much. Anyone have any input on some affordable, decent quality carbon blades?

I also auto'd my Falcon 3D once when the motor came apart in flight. It tipped over when it hit the ground and broke the blades but no other damage.

archiebald

P-Diddy,
Since you say you have a sim, then what I am about to say you can test for yourself.

1) For practising autorotations, you will of course use the throttle hold switch, which means you'll be using the throttle hold pitch curve. Depending on how you have your heli set up, this will probably be the most radical pitch range to help with the auto. So, when an emergency arises such as a flame out, and if you have time, you should also try to immediately hit the hold switch. There might be times when this is not possible but it will give you more breathing space if you can.

2) When doing autos up to 3~4 meters, you are getting close to the "Dead man's curve' I mentioned earlier. With autos, as in may other aspects of flying, altitude is your friend. It allows you to LET the heli drop by using negative pitch. The more it drops, and with the right collective pitch, then the rotors will actually speed up. What you are actually doing is converting gravitational force and drag into rotational energy. Too much negative and you will drop too fast. Not enough and the blades will lose energy and you will surely crash. Then, as you approach terra firma you use that energy you stored in the rotor disk by engaging positive pitch.

Your fear sums up the need to practise "aborted or power recovery autos", where you hit the hold switch and auto down to about 15 meters then hit the switch again to power up and recover. This allows you to practise getting the correct fall rate versus rotor speed without having to worry about the bumpy bit at the bottom.

Bear in mind that airspeed (forward speed or a headwind will help in every aspect of doing autos.

3) Actually a good set of carbon blades are possibly the worst type to practise autos with.
i) They are lighter (generally) so will not be able to store as much energy for the all important positive collective / braking maneuver at the bottom. If your sim allows it, try practising autos with different blade weights / rotor inertia and see the results.
ii) They cost an awful lot more which as we all know, increases the pucker factor by another 3 points which of course means that you are more likely to screw up.

Patto

Archiebald,

Thank you for the detailed response!!

Now, I want to go out and practice the autos from higher up!!

As far as the blades go, the heli guru out at the club field tells me that the wood blades are very aerodynamically inefficient compared to the carbons, so they lose more speed without the engine helping them along.

I'm going to go ahead and try with the wood blades this weekend. I'm going to be shaking like a child who knows that his parent is about to spank him, but I'll do it anyway...