Rotor Blade Management Training

loftus

Super Member
Joined
Mar 17, 2013
Messages
1,340
Location
Ponce Inlet, Florida
Aircraft
Aircam; Previously owned Autogyro MTO
Total Flight Time
800 hours
Seems like the thread on the Training Issue vs Design Flaw has become a bit like the crow-hop vs no crow-hop discussion. I personally do not want to practice accelerating my rotor from 60 RRPM in the MTO, seems like it's an unnecessary risk. If my pre rotator is not getting my RRPM to 160 or above, I clearly need to cancel the flight.
I would like to ask the experts, what specific exercises they recommend to teach rotor handling, and I really hope this will not become just another piling on the MTO / Autogyro design discussion. In my training I learned 2 specific exercises:
1. RRPM up to 160 RRPM, stick gently back then slow increase of engine rpm and acceleration to achieve wheel balancing, and wheel balancing down the runway.
2. As above, except playing with the stick gently a little forward and back while rolling and RRPM about 200 RRPM and getting a feel for the inverse change in RRPM and aircraft rolling speed, rotor drag etc.
I continue to practice these frequently before I fly, particularly if I have not flown for a week or two.
Are there other exercises the experts can recommend?
 
Odd.
You say you dont want to practice spin,n up rotors the proper way, coz you dont like the apparent, " unnessesary risk", but then say you want to practice rolling down the runway with sluggish rrpm and the risk of rollover by playn with pitch changes ina hard linked nose wheeled machine.

Nuthn a bit of rotor management coachn wouldnt fix.

No offence intended, but this sounds like a perfect example of wot ' fly by numbers training' can do to ingrain ignorance of rotor dymamics.
The most basic, effective," specific exersises" to best understand how to handle rotors, is to milk up the rrpm with airflow.

Disclaimer; im not an expert.
 
Odd.
You say you dont want to practice spin,n up rotors the proper way, coz you dont like the apparent, " unnessesary risk", but then say you want to practice rolling down the runway with sluggish rrpm and the risk of rollover by playn with pitch changes ina hard linked nose wheeled machine.

Nuthn a bit of rotor management coachn wouldnt fix.

No offence intended, but this sounds like a perfect example of wot ' fly by numbers training' can do to ingrain ignorance of rotor dymamics.
The most basic, effective," specific exersises" to best understand how to handle rotors, is to milk up the rrpm with airflow.

Disclaimer; im not an expert.
Here we go with the hard linked nose wheel issue again. On the contrary, if one is going to fly a hard linked nose wheel machine, I would imagine these exercises are essential, as managing the nose wheel at the same time as the blade etc is obviously a key aspect of managing an Autogyro machine safely. And I mean no offense either Birdy, but you are hardly being constructive or helping me, except by suggesting maybe that I sell the MTO. All I'm saying is that given that in an MTO there is risk to the machine of damage to the tail with stick back - probably around 120 RRPM is the minimum I'm told - these are the exercises I've been taught.
Again, I ask you then Birdy, what exercises would YOU teach for rotor management. I'm happy to hear how you'd teach spinning up from nothing etc? I can then decide for myself if I want to practice it. Folks keep throwing the term 'rotor management' etc around. I am trying to establish exactly what exercises for a student people would actually recommend practicing, and specifically how to do these exercises, beyond what I mentioned above. Just trying to get something constructive out of the discussion. What steps do you teach, to 'milk up the rrpm with airflow.' ? It appears the main benefit of learning to manage RRPM below 100 RRPM is to anticipate and learn how to manage blade flap. It also appears that over 160 RRPM, blade flap is not normally a concern. There are other issues of concern, but blade flap is not one of them from my understanding.
 
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I mentioned the nose wheel coz it IS an issue if you want to practice wot your sayn.
I dont care wot you fly.
I mite not sound constructive, but i know wot can be an issue.
I dont care bout your feelns, its your neck im thinkn of.
Deliberatly puttn down a sealed strip with sluggish rrpm, playn with pitch attitudes and ground speeds is a recipy for disarster, with a hard nose wheel.
Once its off, keep it off.

I wont suggest anythn you should practice without a coupla facts.
How for off the tail is the rotor wen the head is on the backstop and the teeter hinge centered?
How many degrees of teeter is in the head?
 
I mentioned the nose wheel coz it IS an issue if you want to practice wot your sayn.
I dont care wot you fly.
I mite not sound constructive, but i know wot can be an issue.
I dont care bout your feelns, its your neck im thinkn of.
Deliberatly puttn down a sealed strip with sluggish rrpm, playn with pitch attitudes and ground speeds is a recipy for disarster, with a hard nose wheel.
Once its off, keep it off.

I wont suggest anythn you should practice without a coupla facts.
How for off the tail is the rotor wen the head is on the backstop and the teeter hinge centered?
How many degrees of teeter is in the head?
OK, I'll check those things tomorrow....
Yes, I am very aware of the nose wheel, honestly though, except in a strong crosswind condition where on landing with significant rudder compensation to keep the nose straight down the runway, where I have to be very aware of straightening the nose wheel before before it touches down, the nose wheel is pretty straight in most other situations I can think of. This is why in MTO training, holding the nose wheel off until the aircraft is almost stationary on landing is part of the training.
 
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I personally do not want to practice accelerating my rotor from 60 RRPM in the MTO, seems like it's an unnecessary risk. If my pre rotator is not getting my RRPM to 160 or above, I clearly need to cancel the flight.

That was exactly the sentiments of the official German gentleman I talked to about changing the training syllabus.

The point is that you will be a better and safer pilot if you know how the biggest aerodynamic surface on your aircraft behaves. Not knowing this apparently got a lot of people into trouble, as evidenced by the numerous tip over accidents. I wouldn't feel safe, only knowing what's in the POH and not being able to deal with situations slightly outside of the norm. These deviations from the norm can happen unannounced at any time. Therefore I want to be able to deal with them on an intellectual as well as instinctual level.

Before doing any experiments with rotor management at low speeds, find out what the slowest rotor rpm is at which you can still apply full back stick without hitting anything. This will not only depend on the stick being against the back stop but also on the maximum teeter angle allowed by the rotor head.

Here is what I suggest:

0) On the ground with the rotor stopped and the stick against the rear stop, find out which part of the structure has the least clearance to the rotor. Then take a piece of stiff cardbord and tape it to that very point so that it sticks up about 2 inches (5 cm). When the rotor touches the cardboard you still have 2" of safety clearance before it hits anything on the gyro.

1) Use another airplane at a suitable distance upwind of you and peruse its propwash for wind. Note, however, that it is the rotor that needs to "feel" the wind, not just your face. You could do this experiment without wind, too. The wind is only required to get you a realistic blowback angle. If you do it on a windstill day, your results will be a bit too optimistic. The higher the wind speed, the better. It should be at least equal to your lift off velocity (mostly around 35-40 mph).

2) Get a person to stand well outside the rotor disk but with a clear view of the rotor as well as the piece of cardboard. If necessary, use binoculars. Make sure you are in contact with this person so that he can tell you immediately when the rotor has touched the cardboard piece.

3) Point the nose of the gyro straight into the wind and spin up the rotor as you normally would, i.e., with a flat rotor disk using the prerotator.

4) Once you have reached a point where you know you can apply full back stick (in an MTO this is about 150 rrpm), stop prerotation and pull the stick back against its rearward stop.

5) Observe rotor rpm and note the particular rotor rpm at which your observer signals you that the rotor has touched the cardboard piece. Mark this rrpm on the rotor gauge. Never use full back stick at an rrpm below this mark.

Greetings, -- Chris.
 
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Thank you Chris. Can you then outline your steps for how you would actual do training to to spin the rotors up from scratch etc in an MTO. I would imagine it would be along the lines of stick partially back with forward taxiing into wind etc, bringing the stick further back as RRPM increases and of course avoiding full back until the minimum described above is reached.
 
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Hi Jeffrey,

I would recommend training in rotor management initially only while the gyro is standing still with brakes engaged. Trying to taxi straight while concentrating on the rotor and stick is usually too much and will get you in trouble. Learning is also slower if you spread your attention too thin.

Therefore, you need a windy (but not too gusty) day or a big fan (i.e., another aircraft in front of you) to help you. Alternatively, you have a fellow pilot or (even better) instructor who is willing and capable to ride along and manage all controls except the stick. It is important that you can focus on the feeling of the stick and all the ways the rotor is talking back to you.

You also need to know what the slowest rotor speed is at which you can use full back stick safely (see my previous post). Position the gyro with its nose into the wind and the engine stopped. A stopped engine allows you to listen to the rotor blades. You get more clues that way.

Then you need to develop a feel for the point where the blades just ever so gently touch the teeter stops. Try to get good at identifying that point and knowing what to do to get away from an incipient flapping condition (i.e., push the stick forward and/or slow down).

How you progress from there depends on your personal experience, your particular gyro and circumstances. But the goal is to be able to prerotate to, say, 60 rpm and accelerate the rotor to flying speed by using wind and taxiing.

In Hungary, where I regularly fly, we are blessed with often strong but steady and laminar winds. I spent a long time just sitting in the wind with the blades spinning and the engine stopped. I would first prespin to something liek 150 rrpm and then let the rrpm slowly decay down to the point where the rotor is solely driven by the wind. Pull the stick back very slowly until you feel the slight tap-tap when the rear blade starts to touch the teeter stop. Then push it forward a fraction of an inch. Watch the rotor speed while your are trying to hold a constant angle of attack. Try to find the sweet spot where you can sustain the highest rrpm. It is difficult to write a step-by-step instruction set for this process. Just set aside some time for it and try to do it first with an instructor. Doing it while taxiing up and down the runway is a lot more difficult with associated slower learning, in my experience.

Greetings, -- Chris.
 
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Thank you very much for this; it's very helpful. Having heard people talk about learning rotor blade handling without actually knowing the process, this helps a lot. I'm not rushing out to do it tomorrow, but will certainly ease my way into it, especially if I can find someone to help me with it. Be interesting to hear from others the exercises they have learned, or taught, as well.
 
Sooner or later your prerotator will crap out.....I was taught how to taxi with rotors turning slowly, and feel the rotors bit into the air and increase their speed while causing more drag on the gyro, then increase throttle, and you can feel the blades accelerate.
Here at home I usually prerotate to about 170, I can go as high as 230, but no need to on a regular basis. I am still off the ground in 400 ft.
When at Bensen days, since it is always windy, and there is a whole mile or more of runway, I pre-ro to around 100-120 rrpm and just take off accordingly adding throttle as the blades come up to speed, save wear and tear on the prerotator, plus keeps me in the good habit of not relying on the prerotator so much. I have had to take off with a pre rotator issue, It is nice to know that you can still get home if you can only prerotate to 100 rrpm and still understand how to get the blades up to speed and take off safely.
 
Rotor management is very important to learn and understand. Seems like there have been several incidents/accidents over the last few years that could be attributed directly to poor rotor management.
 
It sounds like there are really two 'phases' of rotor management.
The first is that phase from zero to 100 plus. RRPM or the pre rotation speed, and the second is above this when pre rotation is complete and the takeoff run is actually initiated.
In machines with a strong working pre rotator phase 1 is skipped. I also understand that blade flap is much more of a concern in phase 1. In phase 2 there are other concerns, but blade flap not so much.
 
I practice take offs and landings.

I practice take offs and landings.

I find that by doing stop and goes I learn a lot about rotor management.

I find in the Cavalon if I advance the throttle too soon after touch down that she turns left even if the rotor tachometer is showing well over 200 rotor rpm.

If I wait for the blades to begin accelerating (rotor reversal) before advancing the throttle she accelerates straight ahead as long as there is not too much crosswind.

I find that I learn more from each takeoff and landing if the last one was only four minutes ago.

I feel the tip over accidents that have been under discussion had little to do with rotor management and a lot to do with simple mistakes.

I feel the pilots had plenty of warning that something wasn’t right before they made the decision to pull the cyclic back.

If the pilots had simply aborted the takeoff that wasn’t going well instead of pulling the cyclic back I feel things would have worked out better.

Thank you, Vance
 
It sounds like there are really two 'phases' of rotor management

The 2 phases would be under autorotation speed ( genetaly under bout 60 rpm)and past the onset of autorotation speed.
You can hear it start to auto, if you do as Chris says in wind and no engine.
A properly setup gyro is a sinch to hand start, coz it wont chop its tail off. But a pilot flyn a proper machine will know that full backstick in wind over xx kts will make it teeter excessivly, so he wont give it full air wen he,s hand startn.

If you have the time, and rite blades, you can get them to flyn speed in wind from 0 rpm, without touchn them.
Takes alot of patience and exagetated giggleing of cyclic, but it can be dun.
Trick is, known how much air to feed it and wen.
 
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