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Lesson on Autorotations from Mark Thompson - Printable Version

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Lesson on Autorotations from Mark Thompson - FlyGuy - 06-07-2018

Mark Thompson is trying to get back on the Forum after not being able to log-on for a while. He was on the FB Mosquito page when someone asked, "I'm interested to know how many of you guys practice autos to the ground." I thought Mark's reply as usual was very informative and will help many understand the "baby steps" concept.

I did over 50 autos to the ground when my father and I had our XEL known as "the Mad Mosquito". I started with hovering autos at about 1' and then incrementally started going higher and higher until I was probably in the 12'-15' range. They were easy but I was also a career helicopter pilot and instructor by that time and I never broke anything on the machine doing autos. Once I had the hovering autos down I started doing them from altitude and ending them with a termination to a hover. I did many, many, many of these! Once while practicing autos I entered an auto and told myself I am not taking this one to the ground but at the bottom everything coupled up perfectly and I did it! The wind was blowing about 10 mph and when I initiated the flare I could feel how well the lift was working in the "windmill brake state" When I started the collective pull to cushion the landing it held off better than I expected and I thought I was never going to get it on the ground. This was probably because the rotor system was still flying above ETL. I felt the lift go away just as the heels of the skids kissed the ground. The auto was perfectly timed. I spooled it back up and did several more getting more and more efficient with each one. The Mosquito autos very well! Now, as for advising other pilots (especially beginners) I would not recommend risking your life or your investment just to check a block. Terminating an auto to a hover is actually harder than doing one to the ground but it is safer. If you can properly do an auto to terminate to a hover then in the moment of truth you will walk away and probably not even hurt your machine. I say that confidently because I know well what it feels like to continue past the the point where one would normally terminate at the hover and I assure you from that point on it's really not a big deal. Think of it like working hard and saving a bunch of money over a long period of time and then spending all the money (to reward yourself for all the hard work) in a very short amount of time. That is the best analogy I can come up with for doing an auto to the ground because the hardest part of the auto is like working for the money and the last three feet is like spending it all and we all know the spending it all part is super easy. Question: How do you train for the autos in a single seat heli with no instructor? Answer: Very, very carefully and methodically! Start like I did with the last part first and then build upward from there. Start by sitting in the machine with the engine off! Pull the collective up to about where you think you normally hover and twist the throttle grip to where you think your normally do when you are hovering. Set the pedals about where they normally are in a hover. Look straight ahead! Roll off the throttle while holding the collective where it is and simultaneously push in full right pedal then pull in collective to cushion. Do this static practice over and over while saying to yourself ; "throttle, pedal, settle, pull"! Do this until you hate it but can do it perfectly and say it quickly. Then and only then, start the helicopter, rev it up to 100%, pull in collective (but NOT enough to get it light on the skids) and repeat the exercise being very careful not to pull in collective fast enough to pull the helicopter off the ground after you cut the throttle. After you have done that a few times and are comfortable go ahead and start doing it from a very low hover (about 1'). The event will happen so fast that whatever you may do wrong will quickly be stopped by contact with the ground. You are trying to develop throttle cut and yaw control coordination timing here and you probably don't even need to pull in collective from this altitude but pull it slowly in after touchdown for the feel of it and positive habit transfer for when you are high enough where you do need it. Keep doing this and gradually, over many flights add more altitude but not more than 3' at the max. Once you are very good at this, start practicing quick stops (slow and mellow ones at first). Do them very slow with very shallow flares and gradually build up to faster and steeper flares. This is a coordination exercise to teach you to go from high to low to high power settings smoothly while controlling the pitch and yaw attitude of the helicopter. Gradually build this maneuver up until you can do it intuitively and to the point where when you do it you can feel the "windmill brake state" trying to over speed the rotor. That is the most important part of the auto! Except of course for the other parts of the auto that are all equally as important. Once you have the hovering auto and the quick stop down cold then you are ready to practice the entry. The entry is easy but can be scary if you don't know what to expect. At an altitude of 1,000' and airspeed 45-55 mph look straight ahead. Slowly lower the collective and reduce throttle as needed to keep the rotor from over-speeding while maintaining the same pitch attitude. The nose will have a tendency to drop since the lowering of the collective is reducing the "blowback' effect but this will not be very quick or violent in the initial slow entries. Once you realize the throttle is against the idle stop verify your rotor is at least 100% and stable and that you are in trim with respect to yaw (you should have a windshield mounted yaw string). As soon as you have verified these points smoothly bring in power and collective to maintain 100% RPMR, arrest your rate of descent and subsequently start a climb. Practice the entry, steady state and power recovery until you have it down very well then start recovering with a shallow flare but still at a high altitude (at least 500'). Do it like your early (not-so-quick) quick stops. Gradually increase the speed of the entry and the nose up angle of the flare until you once again see and feel the efficiency of the helicopter in the "windmill brake state". Once you have this down cold then start lowering the altitude of the flare from 500' until you are doing it to terminate with power in ground effect. At this point you are learning what your rate of closure looks like as you approach the ground which will not be apparent at high altitudes. The goal is to enter the auto in trim, keeping rotor in the green, predicting, constantly assessing and adjusting for the intended point of landing (look up "circle of action"), initiating the flare and terminating to a hover with the ground speed at zero by the time the power is pushing the rotor again. Be sure you always push the cyclic forward, establish a skids level hover and pause for a few seconds while you tell yourself; "neutralize the cyclic before lowering collective"! If you do ever take one to the ground make damn sure you neutralize the cyclic before you lower the collective or you may destroy your machine by putting the blades through the tail boom. Y'all have fun but be safe!

Thanks Mark!

RE: Lesson on Autorotations from Mark Thompson - arrow123 - 06-07-2018

Thanks for publishing this - there is a lot of great comments and advice in there

RE: Lesson on Autorotations from Mark Thompson - FlyGuy - 06-07-2018

You are welcome. That was the whole reason for the "Academic" section of the Forum where Mark was a valuable contributor. In the past few years he has been busy training US helicopter pilots in Korea. He hopefully will be getting back to making more regular post to this section.

Recently I have seen on the FB page too many people answer posts on subjects that they really know nothing about or give advice that is not valid or even dangerous. Advice and instruction needs to be based on "fact"! This activity is not that forgiving and the recent events of  pilots trying to pilot a mosi without training in a confined area or flying without understanding the basic concept of an autorotation can put us all at risk in the form of new regulatory restrictions. 

If you already know everything and issues are "no big deal" then you are part of the problem. If you learn something or become more aware every time you fly or prepare to fly, you are on the right track. We should all choose to learn.

RE: Lesson on Autorotations from Mark Thompson - arrow123 - 06-08-2018

(06-07-2018, 03:04 PM)FlyGuy Wrote: Well said 

RE: Lesson on Autorotations from Mark Thompson - Frederic Moreau - 06-09-2018

Thank you Michael for this very important message !