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Straight In Autorotation-2 Techniques


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While I was trained to do autorotations one way, I have seen a second method from other CFIs. I am sure that both methods have good and bad points, but I thought we could explore each method in more detail. I teach in a Schweizer, but I imagine it would be similar in the Robbie.

 

Method 1: Flare begins at tree-top height, about 50'. The flare is said to be a "progressive flare" with the goal being to arrive at 8 feet with near zero airspeed. (On no-wind days this is less achievable.) With a nose up attitude, initial collective is applied (approximately 1 inch) to complete the deceleration. Immediately after the initial collective is applied, the aircraft is leveled so as to complete either a hovering autorotation, or run-on landing, depending on groundspeed. Simply put, a very fast version of a steep approach.

 

Method 2: Flare is entered much closer to the ground, with collective being applied as necessary to avoid rotor overspeed. The aircraft "floats" down the runway in what closely resembles a low altitude rapid deceleration. As the groundspeed bleeds off, the aircraft is leveled, and then collective is applied as necessary for cushion.

 

As I see it, the benefit of method 1 is the ability to auto the aircraft (to a full stop) in a much smaller space. However, if the aircraft flares too much, or too soon, then a purely vertical descent will occur, which is never good. I am told this method, while more effective, is simply more dangerous to teach.

 

Method 2, while being very docile, requires a large amount of clear area to perform. In addition, while students "float" through the deceleration with collective applied, it often re-joins the needles (unbeknownst to the student) and a false float occurs, which wouldn't otherwise occur in a real auto.

 

SO.... I am not an expert, and I am here to learn. ANY thoughts or discussion is much appreciated. Please remember we are referring to piston helicopters. THANKS

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It is better to auto (in real life) to where you can see is clear, either in front, behind, or strait down, (your steep approach) with no or little forward movement until last 150\200 there are times when choosing to go for longest distance is good, but gusting wind, or stronger head wind can leave you short much better to go shorter with a 360 or S allowing for hight to carry out safely, surely the way forward is to teach all so as to prepare the student for all eventualities, & as you say engine out is a different thing to engine idle, there is always some residual HP at ground idle to help

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The goal in an autorotation, as in any other flight regime, is to make the helicopter do what you want it to, whatever is necessary for a safe outcome. Doing an auto to a runway isn't realistic training for engine failure unless it you restrict the touchdown area to a small location, such as the touchdown zone bars, or one runway stripe. Whatever technique gets you into the target area safely is what you use, and that varies depending on the conditions. Teaching only one technique doesn't give the student the instruction and experience he deserves, and if you can't teach multiple techniques then you need more instruction yourself.

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I teach in a Schweizer, but I imagine it would be similar in the Robbie.

 

Not really, the 22 is even lighter inertia than the 300 is. We have separate threads out there talking about the way we teach autos. I think you need to teach best case scenarios until the student is ready to learn some more advanced techniques...like the other posts state...those techniques should be best taught at a manufacturer school, or by some well taught advanced CFI's..

 

I learned in the 22, and your method 2 is what I was initially taught. We flare low and stop our descent just a few feet off the ground....you dont want to do a hover auto in a 22 from 8 feet !..Maybe in a 44, but not in a 22.

 

As far as joining the needles, only if we are doing a power recovery....otherwise that throttle should be held to idle and there is no chance of the needles joining as collective is raised.

 

I think Gomer has the right ideas, but at the PPL level, it seems the CFI's and DPE's are only looking for you to demonstrate the most basic textbook style auto's.

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I'm not going to rehash my auto technique since I have posted it before. It is almost exactly your #1, except, I don't teach 50 feet or any other height in ground school unless the student needs clarification of the concept. In reality flare height will be effected by wind direction (cross, tail, head), groundspeed, rate of closure, and rate of descent. I teach flare height by demonstrating, coaching, and allowing my students to screw up the flare as long as I can recover. Having had an engine failure, and landing in a wide open field, I would never have considered technique #2. It requires too much flare for my tastes, and by the end of the flare with rotor effectiveness decreasing it would make leveling the helicopter more challenging (but not impossible by any means).

 

I believe it is important to teach students multiple techniques for the end of an auto since one size doesn't fit all, but not until they are able to perform technique #1 within 1/2 of the PTS standards. I consider 1/2 PTS to be as mastered as that certificate level can be without excessive training. Training to "make the spot" begins as soon as they can consistently recover within 400-500 feet of their spot, and certainly before they solo.

Edited by PhotoFlyer
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I have done it both ways. Although I taught it more offten the 2nd way as you described. Even at that I was able to bring it to a nice good stop really low over the ground(1 foot or less) almost to a full down.

 

The first one you speak of is a good way to do it. It's nice and smooth and easy for the student to keep more controls and see what is going on. This is what I taught for students who were working on PPL or slow learners.

 

Other pilots I would teach both ways. This gave them a chance to see autos done differently. In real life it depends on the situation you are presented with.

 

I feel more instruction needs to be placed on real life type situations which are taught in the Robinson factory during advanced auto training.

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In reality flare height will be effected by wind direction (cross, tail, head), groundspeed, rate of closure, and rate of descent

 

This is my take on it too. Both methods could work depending on the situation. Both methods could fail.

 

I generally like the sound of at least thinking (starting) your flare earlier. That's when all those factors PF come into play.

 

As you have started, it is easy for your mind and muscles to either speed up or slow down what they have already started.

 

On the other hand, 'starting a movement' (based on reactions) is time consuming. That time may be critical.

 

What do I mean? Well, say you are used to doing the much lower flare with run on. You are all setup to start your flare at your usual height. At the last minute you notice a little wire fence right in your path. Take the reaction time, plus the time required for the signals to be sent to all parts of your body; you're probably too late.

 

However, if you have already started that move, the 'speed-up' signal is relatively much quicker.

 

So plan to start your flare earlier...you can always slow it down.

 

As for the termination, I think too much run on is pointless. While it demonstrates an autorotoation to the ground, it is not that practical in an emergency situation. Again, the longer you can have your disc facing backwards, the slower you will be at flare time.

 

Joker

 

(I used to love doing those 180 full downs to Spot 6 - Left skid or right skid on the six...front or back?) GofG knows what I mean!

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I was taught the 2nd way first and when I finished my training at another school, I was taught more like the first way. I find value in both and as others have said, it's different in every situation. I initially trained all my students the 2nd way as I believe that for them to be able to hit a spot that may have trees, cars, buildings, wires, poles, etc. they need to be able to go right to the spot.

The 1st way, I coined to my more advanced students, the "stretched flare" was what I would show them if they needed to hit a spot that they might not quite make it to under normal circumstances. For instance if they had taken off and were only 500-700' AGL but in a normal auto would put it into a ditch and another 20-40 feet of glide would prevent that, I would do the "stretched flare." The POH for the robbie says you have to bring it out of a max glide config at 500' agl so I wouldn't have them go for max glide at that FL. I would have them enter an auto, trying to make it to the edge of a runway, with the mindset that there is no way we are gong to make it. Then show them HOW to make it. I'd even bring the AS up a little if I needed to if they chopped it WAY short. That way there is a lot more energy to use through the flare to "glide" to the spot.

Works great but again, thats more a part of a little more advanced auto's IMO.

Now granted, to do a full down to a runwya or taxiway, option#2 IS easier for most if it has to go full down, but when are we really going to have a runway in a real engine failure?

:)

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