Autorotation: Hitting the spot

[rabidcat]

I am getting better at autos despite my instructor and my only real hangup is 'hitting the spot.' It is pretty bad actually. In the 22 I can enter a normal auto, switch to max glide, do S-turns, 360, etc fairly proficiently but I just can't seem to accurately judge the spot I am aiming for. I know most everyone has had this problem when they were learning, is it just repetition or is there some other trick?

[hueyracer]

You have to practice a lot before you will be expert on that...

1. Make sure that the conditions (Airspeed, GS, Wind, Height) are always the same when you enter auto.

2. Pick yourself a "visual aid" you will look at over the front panel.
(in my case i always use a spot i am looking at app.a palmwide above the front panel-giving me an imaginary glide path to follow).

3. Enter auto always with the same speed-if you close throttle fast one time, and slowly another time, it will make a big difference.

4. How do you define your flare altitude/attitude?
Using a radar alt will help-also take a look at the horizon when in the flare...

The rest is just practice.....practice....practice...

[EN48]

The rest is just practice.....practice....practice...


IMHO, its ALL practice. Hueyracer's advice may be useful for initial training, but in the event of a for-real auto, you'll have to start with what you are given re speed, altitude, wind, etc and make adjustments to deal with the circumstances. One of my instructors is in the practice of covering the flight instruments during autos, and insists that the whole maneuver should be performed looking out the window and "listening" to what the rotor is doing. Too much practice using a "mechanical" technique may actually be counterproductive. Let me be quick to add that I am still learning how to hit the spot. Repetition seems to be the most useful approach.

[spinwing]

Mmmmm ...

rabidcat .... don't sweat this too much ... at your stage what an examiner will be looking for is the entry .... an attempt to be able to get to a 'target' area and then the flare/arrival such that when all the noise stops you and your pax will able to walk away to a safe area, turn and gaze at the mess and have a laugh!

As experience increases you will find that you will be quickly able to get into the 'auto' then find the spot on the 'bubble' that is not moving ... your touchdown will be some 50-100' beyond that spot .... once you become proficient at quickly picking up this stationary spot ...you then learn how to manipulate the aircraft to place that spot just short of the desired touchdown point .... VOILA ... success ... but it DOES take some time !

If it were easy EVERYBODY would be able to do it (first time) !!!

Good luck ... ;)

[ReverseFlight]

Make sure that the conditions (Airspeed, GS, Wind, Height) are always the same when you enter auto.

Sorry but I don't agree with this approach at all. You are up against Mother Nature and she controls you, not the other way.

The way I was taught is this : apart for obviously aiming (azimuth) for the spot, how do you avoid under/overshooting the spot ? Fly a base leg and turn in final when 100-150 ft AGL (assume you are not set up for a straight in). Get your airspeed correct, so increase your standard auto airspeed by half the headwind element if any. Moreover, it's all to do with the groundspeed as you approach the spot - do not use height AGL to judge the timing of the flare. When the groundspeed looks fast, that's when you initiate your flare.

[Shawn Coyle]

EN48's closest to the mark. Looking outside is the key. Cover up the airspeed indicator and learn to judge rate of closure with rate of descent.
The three types of autos that should be covered first to make sure you know how to use the height and speed available are:
a) shortening range (don't turn unless you absolutely have to- go 90 degrees to the wind and slow the speed to nearly zero groundspeed until the sight picture looks right, then positively simultaneously lower the nose and turn towards the spot. Turning more than 90 degrees to the spot only makes judging things much more difficult
b) going for range - go to maximum speed in autorotation and minimum rotor RPM. Hold this till you get to the flare, and then use all that speed to hold the flare height nearly forever.
c) autorotation where you have to turn to line up in to the wind (a spot a long way downwind of where you are.
When you've mastered those, nearly anything else is merely a minor adaptation of those technique.
PM me if you want the chapter in Cyclic and Collective about advanced autorotations.

[topendtorque]

Just don't let it worry you too much is the main thing.

Excellent advise in this thread, as usual, and especially SpinWings, where he talks about the touchdown spot in front of the glideslope.

There may be something else; If you have ever had a lazy eye, or don't even know about it, (mild astigatism or some other reason) then it could quite well be that when you are getting stressed that you are not getting the best benifits of the two eyed distance measurement, or depth perception.

See if you can short circuit the problem by giving yourself markers to work with. spinwings' is ideal.

Me I had that problem, i could never land a fixed wing on the same spot twice, when learning circuits under indentical conditions each time. That's when I learnt to look down, mark, power back a bit (the same bit each time), look down , mark, etc. just a bit of extra work and at the end of the day (oh dear that expression again) you will end up being smarter than those who don't have to work at it.

Those who have to work hard to get there have well proven their good capability compared to those who find it easy, i have found.

Certainly when / if the real crunch comes all of that practice will mean that you will without thinking point the machine, and control it easily, at the best and only spot around, that you have already picked out and it will be simple.

Above all if you feel that you are getting a bit crowded with the instruction ask your instructor if you can do something else for a while, or practice the sequence for a bit with someone else. no harm done for sure. go have a drink of tea or milo, not coffee.

all the best tet.

[Two's in]

rabidcat .... don't sweat this too much ... at your stage what an examiner will be looking for is the entry .... an attempt to be able to get to a 'target' area and then the flare/arrival such that when all the noise stops you and your pax will able to walk away to a safe area, turn and gaze at the mess and have a laugh!

Great advice from spinwng. Experience will improve your performance, but remember that if you don't get it right at the top of the auto - with a reflexive entry before you lose too much rrpm - what happens at the bottom will be a largely academic exercise.

[Alphabet]

I just can't seem to accurately judge the spot I am aiming for.


I'm new to this site so not sure if I've extracted the quote correctly.

Anyway in the event of any emergency requiring an auto/PFL you should not be judging the spot you are aiming for (Aircraft flying you) but picking a suitable spot for the forced landing and you flying to it. If this point is static in you windscreen then you will make the spot but if it is moving up or down the windscreen then you are overshooting or undershooting and need to use one of the techniques to make good.

Another common fault is don't select a spot but use a line preferably about 1/3 of the way into a field and use the full width of the field to make that 1/3 line.

[newfieboy]

You guys crack me up, pick a field ,Mmmm hows about pick a tree. I just spent the best part of 8hrs today on a longline doing precision stuff with 2000lb loads as I do most days, getting eaten alive by flies, bugs etc, in the Boreal Forest, we dont have the luxury of fields, I wish :ugh:

Also don;t have the option to putt about all day at cruise speed and 1000ft practicing entering autos at a set G/S,alt etc. When the donks quit, they quit, all I gotta do is get the pole down and punch the load, sounds easy, from 150ft, zero airspeed, yeah right.... pick a field, ummm , gonna be lucky to even pick a tree, guess thats why they pay the big bucks, ha ha, welcome to the operational world in Canada.........Oh and if I see the spot stayin in same place on my window, gonna figure I;m real lucky somehow, cos the real picture is going to be pretty damn blurred. Bin there, done it, got the Tshirt.

Oh to be bimbling round Blighty again with all those options.......:D

[EN48]

Bin there, done it, got the Tshirt


Finally - some realism! :ok:

[SASless]

The only instrument of importance is the Rotor Tach.....we live and die by Rotor RPM. During a real engine failure.....and autorotatiive landing....one cannot have too much Rotor RPM at the bottom. The Airspeed Indicator will show you Min Sink and Max Glide airpeeds (if you remember them) and when used in conjunction with Min Nr while maneuvering will give you the best performance for your particular aircraft. They are reference points.....not etched in stone.....move the controls to make the aircraft do what you need to do to hit that target you picked out at the start of the maneuver.

Arriving at a bad spot with bags of Nrand some airspeed is far better than landing at a great spot with no Nr and no airspeed. Always have something in the bag to trade!

Pick your exact spot....tree....bush...pond...road junction....or landing pad...helideck...ocean....what ever and do what is required to find yourself hitting that exact spot. If you over arc....S Turn, slow down, lower the lever some more....under arc....raise the lever a bit...get to the best glide airspeed and hold it until you regain your angle or cannot make it to the exact spot you picked at the very start of the maneuver.

Get into the habit of picking the exact spot you intend to land every time you begin an approach.....don't just aim for the airfield then pick a runway...then pick an area of the runway...then pick where on the runway....pick the exact spot.....visualize the skids setting on an exact spot....from the very start of your approach. Get into that habit during "normal operations" and you will do the same thing during an "Emergency".

[newfieboy]

SASless,

Couldn;t agree more, rotor speed, rotor speed.....you can never have too much, coincidentaly just did my PPC 2 weeks ago, check pilot and I had this conversation about overspeeds, and both came to conclusion, F#### the overspeed in real life....least of our worries, and we both had donks quit for real in times past, by the time we reached spots , rotor was pretty much doing nothing, re hard landings, but walk away.

Kinda hard when the donks quit, when your;e doing vertical reference, at 150ft to make any sense of anything we were taught, by the time you realise, and get your head up, you have just got to go with the flow and hope the life presavation that kicks in works, although always been taught in that situ, pick the tree/spot if your lucky and don;t change your mind, no time, just go for it.......worked for me
.PS SAS, when you flew N.Sea, did you ever fly outta Strubby or Bristows at Holten le Clay I think it was Late 70;s if ya did, mayb it was you I heard goin out at night.... small world.

[rabidcat]

Very interesting. I have noticed that most of the techniques suggested about using the non moving spot on windscreen etc are not taught by my instructor. In fact, really the only thing my current instructor has taught me is to cut the throttle, lower collective and maintain heading with pedals, rpm management, pick the spot (vaguely), and how and when to flare and level skids. Beyond the basic controls of the maneuver, he has given me nothing on actual technique... I really appreciate all of your help. Autos have been embarrassingly frustrating for me. I started autos at around my 20th hr of flight time, and I am currently at 75 and am no better off really... Embarrassing... let me say it one more time... Embarrassing...

Thanks again everyone

[tony 1969]

"Cut the throttle" to enter auto in an R22 ?
Cant remember the Safety notice number but please lower the lever first...

[SASless]

My signature line.....and will probably be etched into my Tombstone is.......
"Limitations are for Normal Operations!"

There is nothing normal about crashing!

An undriven overspeed is no big deal if you are headed into the trees or some very unhealthy looking place....RPM is thy Lord and Saviour!

At least one Shell Aviation Advisor learned my Motto while flying in the 212 Sim at FSI......he got to experience what a Thunderstorm was all about while on approach into DFW....using the same weather model developed from the Delta Airline crash that generated the "Micro Burst" concept. He did not appreciate the method used to teach him....but later on accepted the universal truth of the motto. Hopefully, he has passed it along to others.

[EN48]

you can never have too much


My instructor is fond of saying, " I cant recall anyone who has died as a result of too much rotor speed."

[SASless]

Rabid,

The old grease pencil mark(chinagraph pen) on the windscreen should have been explained about lesson two in your flight training. It is the basis of all approaches in helicopters. It is related to the concept of a constant angle approach....keep the dot on the target and adjust apparant rate of closure and you will fly a constant angle during the approach. At the end of the approach....the target of course must slide under the aircraft but for almost the entire approach the dot on the target works a treat.

Sometimes a change of instructor can be beneficial as we all have things we teach better. A different instructor may have the ability to teach you autorotations better than your current instructor. No slight to your current guy....but sometimes a change is good.

[topendtorque]

Cant remember the Safety notice number but please lower the lever first...


SN37


" I cant recall anyone who has died as a result of too much rotor speed."


You should also refer to SN36.

Rabidcat. please be careful, the most important thing is that your aircraft is set up IAW the Manufaturers Manual.

Ask you friendly engineer to refer you to the section regarding the correct rigging of auto RPM. in the Robinson manual it is exceptionally well laid out. The most important thing in autos is the lowest ROD consistant with the prevailing AUW. That will always occur at the correct auto RRPM setting.

Having the RRPM screaming its' head orf at impact is not a good idea.

I myself have seen a situation where the ELT went off before the low rotor RRPM horn. what does that tell you?

With regard to the operationally tight areas etc that our good friend newfieboy refers to, please don't worry about that so much just now.

You might fluke a job where you are always above 500'AGL and good EOL landing areas, the mental selection of which must be your constant companion.

Sure many of us have been faced with many unexpected and seemingly impossible situations, not always in R22s.

Be assured that your practice in the basics now will stand you in good stead as it did us, IF that day ever happens.

Plenty of R22 pilots went more than 10K hours without ever having a mishap.

One thing that Frank is known for and that is that every mechanical mishap that happens to his machines he will work tirelessly at correcting.

Forget the hyperbole, concentrate on the basics, you will get there.

cheers tet

[hueyracer]

Maybe we could all fetch our balls and put the back in again....?

We are talking about a BEGINNER-and about how he can improve his technique...
It doesn´t help him to hear big stories about VR, LL and other crap.

He wanted to know how he can IMPROVE HIS TRAINING.

And again i suggest:

First try to start entering autos from the same altitude and with the same speed....
That leads to a point where you are entering your glidepath at the same angle all the time...

Then you develop the "eye" to be able telling when you have to do what to hit your spot...

At the beginning-your spot will be several dozens of meters big....getting smaller from time to time...
When you are hitting the same spot within a meter ALL THE TIME-you can think about doing autos out of the "dead man´s curve"..
(Don´t worry about that now...).

That was the way i taught my (military) students how to "hit the spot"....and it worked all the time...

And for all those still telling you "one cannot have enough rotor speed"...
There is a reason WHY there is a lower AND an upper limit...

Exceeding the upper limit can result in a loss of the main rotor-or cause big damages so "hitting the spot" is then the most minor of your problems..

Try to train-you will find out that you are always looking outside the window first time....then, when developing your technique, you have some "green balls" left to observe the instruments.....and at the end, you do not need the instruments at all, because you KNOW everything when you are looking out of the window again...

[EN48]

You should also refer to SN36.


He was referring to real helicopters, and taking a bit of license to make the point that a modest overspeed at the end of a for real auto is far from the worst thing imaginable. To quote my spiritual advisor on this forum: "ass, tin, ticket."

[Alphabet]

You guys crack me up, pick a field ,Mmmm hows about pick a tree. I just spent the best part of 8hrs today on a longline doing precision stuff with 2000lb loads as I do most days, getting eaten alive by flies, bugs etc, in the Boreal Forest, we dont have the luxury of fields, I wish :ugh:


Blah,blah,blah.

'Newfieboy' In what way was your reply constructive to the guy who started the thread? Or should I have just swung the lantern too based on all my experience in different parts of the world!

[EN48]

He wanted to know how he can IMPROVE HIS TRAINING.



OK - point taken, but its important have the mindset that an auto is usually an emergency procedure, not a precision maneuver such as a loop, roll, etc in an airplane, and this requires being (eventually) able to perform an auto successfully under many different conditions.

[SASless]

Exceeding the upper limit can result in a loss of the main rotor-or cause big damages so "hitting the spot" is then the most minor of your problems..



An effective reading of the thread shall show the concept of having plenty of Rotor RPM at arrival during an EOL pertains directly to actual emergency landings and clearly suggested the real danger is arriving without ENOUGH Rotor RPM to safely land the aircraft.

Far more folks have been hurt....and helicopters destroyed by the lack of Main Rotor RPM than too much. If the aircraft is properly rigged there should be danger of causing one self any harm by an overspeed situation.

Again....I put forth my view on this.

Limitations are for Normal Operations!

There is absolutely no reason to worry about damaging an aircraft by overspeeding a rotor when you are about to crash it....the rotors are probably going to be trashed anyway and one might as well use them up saving yer hind end.

Yes.....the phrase "Ass, Tin, Ticket!" applies to this discussion on real life engine out landings.

Rabid has gotten some very good suggestions and the discussion branched out to a discussion on emergency landings....which cannot hurt anyone to read it. As in all things....pick the pretty berries and leave the bad ones.

[hueyracer]

We are not talking about DAMAGING a helicopter with too much r-rpm....we are talking about loosing lifes because of too much r-rpm..

EN48-I agree with you in that point...

There is actually no sense in "hitting the stamp" in an auto-that is just a method of training....

In an actual emergency, it is not important to land on the spot-but it is important to fl the helicopter down to the spot you want to....
In an actual emergency, i would like to have the r-rpm at "high green"-but there is no way i am letting it increasing to the high red marking...
I have seen a helicopter which went through the high-r-rpm stage......not a nice wreck at all.....


And :
I do not agree to this "limitations are for normal operations"....
There are also limitations on emergency procedures.....and there are reasons WHY there are limitations on emergency procedures..

We are still talking about a "Beginner".
And to tell a beginner that "limitations are for pussies".....is not a good start...(i am exagerating...)

SASless:
You are right.
After training "student-autos" it is VERY important to know that things will be different when the engine quits in real life.......but there are instructors out there that should tell their students about that....

[rabidcat]

Well you guys have succeeded in explaining quite a few things. In an emergency 1st and foremost fly the helicopter, RPM's are life, keep it within limits for training at least. All of you guys have given me great input and I am not so daft as to try and do it all at once or inappropriately. I am going to read and re-read all of you guys/girls responses and take the little bits of knowledge that I need, when I need them, until it all comes together. I am not sure my instructor (who is in charge of cleaning the windscreen after each flight) will take kindly to the grease pencil method, but I will definitely suggest it. I have never looked for the area that appears to be stationary, and now I am very curious... One big solution to this problem will come in about 9 days when I am done with private and move back to my original instructor (who is awesome). We are going to revisit the autos.
Great job and thanks again.to all of you.

[the coyote]

keep it within limits for training at least

It worries me when, after all this wisdom, a thought like this now exists in a fresh pilots mind. That thought is very close to "as soon as something abnormal happens, then all bets and limits are off".

That is exactly why I have never liked this "You can never have too much RRPM in auto" mantra... "don't think about anything else, just make sure your RRPM is high" etc.

In my opinion it teaches a single focus and a lack of understanding of the whole equation, and poor RRPM management. RRPM management is the key when power is lost. Those limits are there for very good aerodynamic and structural reasons, do not ignore them.

The ultimate rotor overspeed limit is when it fails. SASLess, can you tell me exactly at what point the rotor system will let go in an overspeed, so I know just how much overspeed at the bottom of an auto I can accept and get away with? Do I now have 2 sets of limits to abide by, the published ones, and the emergency "anything goes" ones?

Don't forget that ROD is a consideration in autorotation, it is usually this that kills people when the ground arrives. Having unnecessarily high RRPM also means an unnecessarily high ROD which also must be arrested. More RRPM at the bottom to deal with my higher ROD that I must now lose before touchdown.

I acknowledge that this whole argument is geared around "you are less likely to die with high RRPM than low RRPM" in that poor RRPM management usually leads to it being low and the resulting high ROD from that is not escapable.

But surely training is when we learn how to do it right, so that when the real emergency comes we do it absolutely right, and not a whole new way because all bets are off.

[rabidcat]

I was trying to settle the argument for everyone.

Alright Coyote, if/when the engine takes a nap, I'll revert to my awesome training (which will re-commence in 9 days hopefully) and stick to the green, but if I have a bit extra revs I'll pull a bit of collective and avoid the overspeed, but I won't freak that they're a bit high. How's that? Is that the appropriate attitude for the new guy? (serious question, not sarcasm)

I think I get the point... when the engine kicks the bucket, don't overfocus on green RPM's and miss the point of getting on the ground alive, but don't be shooting for an overspeed and make 2 emergencies out of 1.

[the coyote]

Alright Coyote, if/when the engine takes a nap, I'll revert to my awesome training (which will re-commence in 9 days hopefully) and stick to the green, but if I have a bit extra revs I'll pull a bit of collective and avoid the overspeed, but I won't freak that they're a bit high. How's that? Is that the appropriate attitude for the new guy? (serious question, not sarcasm)

Rabidcat, I am not trying to tell you what you should or shouldn't do, nor what attitude you should or shouldn't have. I am merely stating my opinion.

However, should you have a genuine emergency, and you revert to your training and keep the aircraft within its limits during that time, I would think this is an appropriate course of action to take, and one that is likely to lead to a successful outcome.

[rabidcat]

Cool, yea I was not being defensive, just trying to figure out the general consensus on what is acceptable. Appreciate the input from all of you.

Oh to be bimbling round Blighty again with all those options

So, in plain old American, what does that mean? It is just too british for my dictionary :E

[SASless]

Coyote,

Have you ever done an airtest to adjust Autorotative RPM on a helicopter? Does your company routinely do such checks? Do you understand how and why those checks are done? Do you accept an aircraft properly rigged cannot achieve rotor shedding RPM in autorotation? Do you adjust your settings for the conditions you actually fly in?

Now assuming one is flying a properly rigged aircraft....one can accept the fact that actual autorotative RPM will vary depending upon various factors such as aircraft weight, airspeed, density altitude for example thus one needs to monitor the Actual Rotor RPM and control it by means of collective (primarily) and airspeed or acceleration or deceleration (loading) but only relatively minor variations should occur. (Remembering the aircraft is properly rigged.....you do fly properly rigged aircraft do you not?) The Rotor RPM might exceed one of the limits but not by much.....nothing a small touch of collective won't cure.

In an actual emergency, I suggest priority goes to aircraft control, hitting the desired safe landing area, and worrying about exceedances becomes secondary. There are buffers built into every limitation. Rotors do not automatically and instantly shed themselves if you exceed the normal limitations limit.

As having insufficient Rotor RPM is a sure killer......proven over and over again through the ages of helicopter flying....we should ensure we get to the bottom with as much RPM as we can muster. That can be done by a simple maneuver called "flaring" done at the very bottom. That connotes flying the machine in such a manner as to have airspeed and collective position to trade for increased Rotor RPM. Again, any exceedance is going to transient as landing shall require the raising of the collective to slow the ROD and ground speed.

As to Rate of Descent (ROD) you worry about.....sheer collective position alone will not produce a ROD that is problemattical....only when you include certain airspeeds, turns, pitching movements, might that happen. You remember the Blue line on the Bell 206 series for example?

Somewhere in this discussion I failed to mention the Golden Rule of Helicopter Flying...."THINK!". I see your expressed worries as falling short on that. You suppose we advocates of having lots of Rotor RPM as ignoring a long list of factors and experience when we express our views.

When things happen fast as they can in helicopter flying...."Thinking" sometimes becomes more reacting than reasoning....and if one is predisposed to remembering to have lots of Rotor RPM rather than worrying about whether it is at a certain RPM...odds are....you will be able to lean on a Bar somewhere and regale your compadres with a harrowing account starting off with "There I was with nothing on the clock but the makers name....and the Donk died.....".

You are quite right when you pose a concern about exceeding published Limitations willy nilly....but let's add in all the factors that preclude your imagined imitation of a failed collection of Boomerangs caused by an grossly overspeeding Rotor system.

[birrddog]

Have you ever done an airtest to adjust Autorotative RPM on a helicopter? Does your company routinely do such checks? Do you understand how and why those checks are done?
SAS, could you please elucidate what you mean by the above for those of us who are less erudite than yourself?





* Got to make up for being less erudite where I can :)

[chopjock]

I'm a bit of a dab hand at practicing auto rotations. I prefer to approach the flare at min RRPM (thus also min ROD) and prevent it from raising more than just a touch by raising the lever. I think if you have your rpm on the high side then your ROD is too fast.

[hueyracer]

Being a maintenance test pilot, let me explain to you that one cannot adjust autorotative R-RPM.

You can only adjust the warning light/audio step.....or je-adjust the reading instrument..

The r-rpm is not adjustable...
Think that you meant that-but it is misunderstandable...

If r-rpm is high green (or over) BEFORE the flare, there will be a massive exceeding of the main rotor-rpm limitation when doing the flare..

But finally i think we are talking about the same things....

[oldbeefer]

What! I have just retired from being the MTP on AStars and 412. Both had an auto check post servieing and, sometimes, it was out of limits for the weight/temp/altitude on the day. When that happened, the RRPM were adjusted mechanically to bring them into limits ( -0 to +10 RRPM of datum for the 350 and +/- 3% for the 412).

Onto you're next point, if the Nr is high during the flare, why not use collective to contain it? Basics!

[hueyracer]

You can balance the main rotor blades to bring them into trim (or use the trim tabs -depending on your type of helicopter) -but how on earth are you going to adjust autorotative r-rpm?

We are NOT talking about adjusting the normal r-rpm during flight...just about the free-wheeling r-rpm....

Why should one go into the "high-risk-area" of massive overspeeding, when he needs to pitch the r-rpm down afterwards?

I agree if you say-keep the r-rpm in the high green limit.....so you have more power to cushion the landing..
But i disagree (in my own personal opinion and experience) if one is continueing telling to keep the r-rpm highly over the limit...

[SASless]

Being a maintenance test pilot, let me explain to you that one cannot adjust autorotative R-RPM.


If I had any number of maintenance manuals to hand I would post the procedures laid out for doing just that. I have done such flight checks on Bell 204, 205,206, 212, and 412's; Sikorsky S-58T and S-76's; Chinooks and Alouettes and MBB products.

How about explaining why one cannot do so please?

[407 too]

Thread drift, but yes, you can adjust your autorotation rrpms.

I'm sure all of us pilots have heard the term "flats" from the engineer when doing track and balance flights.

in track and balance you can adjust blade weight, trim tabs and angle of attack.

you set autorotation rrpm by adjusting "flat pitch" angle of attack by means of push rod length, acheived by turning all push rods a set amount of nut "flats" to correct for over/under rrpm on an autorotation. (for Bell anyways, not sure on others)

This autorotation rrpm check should be done after the completion of every track and balance.

[Lonewolf_50]

Comment on both teaching and learning autorotations:

It has been some years, but I used to teach a special circular autorotation scan (Seahawk) that accounted for line up/spot (target) position in windscreen, airspeed & NR (really needed to be scanned together), altitude/radalt (depends on phase of auto ...) and ball, then back out. It was my teaching approach that the key to a good auto is a good entry (down right idle turn was the Jet Ranger mantra, but "control Nr and Airspeed is generic as a truth) followed by a fast and sustained scan, with corrections to match.

We fixed quite a few problems among novices with teaching them the scan, and what corrections / counter corrections (every correction has a counter correction, doesn't it?) got you the performance you were looking for.

I see some advanced skills being discussed here. Is it fair to say autos to a spot are an advanced skill? (Is that the consensus in the civil world? I am a few years out of date here).

I tip my cap (seriously!) to those who know their aircraft well enough to control airspeed through visual reference to horizon, outside reference, and Nr by audio cues.

If you practice enough, and have a decent outside ref, you can estimate flare height. Without a radalt, that's a required visual skill to learn early in life, but if I recall, flare height is somewhat model dependent.

For our OP: has your instructor taught you a specific autorotation scan?

A tailored scan for a task seems a good way to stay ahead of the aircraft.

for hueyracer: we adjusted auto rpm after every maintenance check flight, usually adjusted for season and weight. (The procedure was in the maintenance manuals). The idea was that you'd have a ballpark "good" NR if you lost engines, or had to auto for other reasons, seasonally adjusted.

Now that I think of it, the charts had OAT as a variable. Grrrr. Been too long.

[Hughes500]

Before we give hueyracer a hard time is he having a problem with his English ?
If not then blimey, all helicopters that I know of have to have their autorevs adjusted, otherwise you can end up having all sorts of fun in autos !! So who passes German air test pilots then ?:eek:

[Senior Pilot]

SAS, could you please elucidate what you mean by the above for those of us who are less erudite than yourself?

birddog,

As SASless said (about auto RPM checks), there is an auto RRPM checking procedure within the maintenance manual for nearly all helicopters.

Basic procedures are to set a stable auto at flat pitch (minimum collective) and datum IAS, then record at a specific Density Altitude the aircraft weight, OAT and RRPM (and maybe one or two other parameters). After landing a check with the appropriate graph in the MM will give the target auto RRPM for that height and temperature which is corrected for weight. Compare target auto RRPM to the recorded auto RRPM, and adjust equally all blades to increase/decrease auto RRPM. Repeat check flight until autorotation RRPM is within set parameters.

If the helicopter isn't set up iaw the manufacturer's auto RRPM specs, you'll be chasing your tail trying to perfect your auto technique, IMO. You may have either a high auto RRPM or worse, very low auto RRPM, and be unable to get the required autorotational performance from your helicopter.

[the coyote]

SASless, I am still waiting for your answer to the question I asked of you.

Here it is again:

SASLess, can you tell me exactly at what point the rotor system will let go in an overspeed, so I know just how much overspeed at the bottom of an auto I can accept and get away with?

If you can't answer this, shall I presume you don't know?

Your whole argument falls over if some poor bugger just happens to be flying a machine that isn't correctly rigged (and/or is overloaded...) and does shed a blade at the end of the flare, snapping his neck in a nanosecond. He is still dead even if he's a foot off the ground. After all, it is probably the poorly maintained helicopter that is more likely to fail.

By the way, the answer to the long list of questions that you fired back at me (how DARE I question you!), is YES for all of them.

[spinwing]

Mmmm ....

My how the thread changes .... by missing just half a day of posts .....

I was seriously shocked to read 'hueyracer's' post re Auto RPM adjustment ...

I will give him the benefit of the doubt with regard language ..... but now have a worry about the standard of maintenance pilot training in the German Military.

Without putting on my 'Maintenance Engineers' hat I must say that Auto RPM checks post maintenance are probably of the most important checks to be done on a rotorcraft.

Those that have ever changed a machine over from/to fixed float configuration will know that the 'Auto Revs' change quite dramatically and definitely need to be correctly re-rigged IAW the maintenance manual ...

In fact you will find somewhere in the RFM (& Maint manual) there will be a 'minimum aircraft (flying) weight' which is all about ensuring that a 'correctly rigged' and configured aircraft WILL be able to get into 'safe steady state autorotation' ... it is I believe a certification requirement.

Can we now stop concerning 'rabid cat' any further! :=



:E

[imabell]

sasless is writing the same words that i say to pilots, that in a real emergency situation life it is better to have too much rpm that too little.

coyote, no ones having a go at you, we are just expressing opinions as you said yourself. nobody said to have massive overspeeds, all that has been said is that it is better to be a bit high than to be obsessed with limits when the situation is not looking good.

pilot to boss; yes boss i wrecked the machine but i made sure the rpm was in the green, i was adjusting it as i went in.

sasless has been around a long time and i am sure it is because he is a very practical pilot and not a pedantic, the same as i try to be and i think we will be around a lot longer because of that fact.

[birrddog]

Senior Pilot, thanks for the reply.

Reading what you posted, it makes perfect sense; what does not make perfect sense (to me), is why this is not taught as part of the PPL or CPL syllabus (at least never taught to me).

One could argue this is more relevant than some of the other course material.

...honest Mr Instructor, the only reason I was hunting after the RRPM in that last practice auto was because this helicopter was not calibrated correctly for autos :O

One learns something new every day!

[the coyote]

imabell, I couldn't agree with you more. I am a big believer in being practical, and I am not about crashing a machine while trying to keep it in within limits if it can be saved otherwise.

I guess what I am putting forward is rather than say "you can never have too much RRPM" why not say "it is crucial that you manage your RRPM effectively at all times". One tends to make a pilot ignore it, one tends to make a pilot give it the due attention that it rightly deserves.

I too have done a lot of autos, and I have gone to the ground with the engine silent (twice), and I too would prefer more RRPM at the end than not enough if I had the choice. But it can be easily achieved without spinning it off the clocks on the high side.

If what SASless is saying is right, then why don't the manufactures say in a genuine emergency, you can never have too much RRPM?

[Senior Pilot]

Reading what you posted, it makes perfect sense; what does not make perfect sense (to me), is why this is not taught as part of the PPL or CPL syllabus (at least never taught to me).

One could argue this is more relevant than some of the other course material.

There will be many things during your flying career that you will pick up along the way, or by osmosis ;) This is probably only the first of many, and I'm pleased that Rotorheads may have helped you.

Most companies (and the military) will tend to use more experienced pilots to address maintenance issues on flights, for obvious reasons: they will have the knowledge to properly analyse anomalies and assist rectification of faults in post flight discussions with the ginger beers. Even the proper logging of engine power assurance figures on a regular basis is a skill that is not always taught during training, but a chat with your instructor to ask for advice on how to may reap great benefits. Not the least, it will show your enthusiasm and willingness to learn :ok:

[hueyracer]

Disregard everything after good morning....


The way senior pilot wrotes it is EXACTLY the way we are doing it..

So i have to admit-i DID understand you wrong...

The auto-r-rpm is checked to stay within specific limits.....and if it isn´t, you will adjust the settings..

Within the military, we FIRST tune the rotor in powered flight...thereafter follows that (under normal conditions) the system is balanced perfectly so no more adjustments have to be made for auto-r-rpm.....
We just check it-and in 9 of 10 cases there are no further adjustments necessary..


Hopefully we are NOW talking about the same....?

:ok:

[Shawn Coyle]

You would be hard pressed to run the rotor RPM up to the point where it would start to come apart. Drag increase due to RPM will, at some point, become self-limiting.
You may do some long term damage to the components, and damage that might make it necessary to replace the dynamic components for no other reason that they haven't been tested or proven beyond a reasonable speed, but I doubt you'd ever overspeed anything to the point of immediate failure during your real autorotation.
The only catastrophic failure I know of related to speed was due to an engine runaway from idle (65% to 117% in two seconds) that severed the tail rotor driveshaft because of the sudden surge in torque (more than just speed).
Has anyone ever heard of an overspeed that was catastrophic?

[topendtorque]

To summarise lets take the simplistic R22 Beta model.

Empty weight say 861lbs.(FROM MY pfm)

Minimum allowable Gross weight to drive the rotor system is 920 lbs.

Think for one second, when will the aircraft enter the EOL phase says inventor Frank. Right the aircraft is full of oil, with a pilot and a dumb ass pilot at that who has used all of the fuel, so calculate as follows;

empty weight plus minimum allowable pilot weight with doors off, 135lbs. = 996lbs.
Min AUW for safe EOL is 920lbs, hey presto we are safe.

Mother nature, that's good ol gravity, will therefore turn the rotors fast enough to have a happy downward flight and successful termination.

Franks' engineers will have also provided that at the minimum ROD that is possible, as long as the aircraft is not overloaded. At this point we say 'Thank you Frank':ok:.

I have only said thank you Frank three times, although that may have been mixed with blasphemy about his bloody drive belts or upper bearings, but there are many times I have said Thank you to Arthur. He was a top dude.

Now when checking auto RRPM always have the collective on the bottom,

it says so in the book but no one has said it here yet.

You will find that there will be a straight line variation pretty much between
- RRPM at minimum Power off RRPM limit (90%) at that minimum weight, and
- RRPM at top of RRPM limit power off (110%) at max AUW. You can look at the Maintenance Manual chart or work it out on the back of an envelope.

The engineer will adjust as necessary.

What no one else has said here so far is that by following the book as above you will be blessed with the full collective lever available to apply at the bottom to slow things down, isn't that great?

Because if you were a damm fool or a know it all and had the auto RRPM set too high for a reason known only to yourself you would have the collective some ways up at high weight to maintain it in the green, or at a low weight you might have had it right down with RRPM right up at the top of the green.

In each event you will have given yourself a higher ROD than necessary and certainly a lot less collective to pull at the bottom.

Dumb eh? :{

I could put my final edit in here and say that the higher the ROD that you have the more collectiove you will need and also the harder it will be to learn the basics. REAL, REAL DUMB EH?:*:=

Besides every thing else that is said here and I will argue with anyone, high ROD regardless of the RRPM at the time, is what kills, maims and hurts, work and study at getting it low.

That is not to say that during EOL flight you may occasionally encounter slightly high RRPM, turning for example especially towards the gyroscopic precession direction, or during a tight flare. Trees a bit close you know, that sort of thing.

No, as others have said don't worry about that too much but report it each time to the engineers. I had the dubious luxury of owning an aircraft once (R22) that had the spindle bearings replaced after 300 hours of instruction including autos. They were close to failing be jeeesus, so don't do it if it can be avoided the MM book knows best.

That's pretty much it.

But I will finish with a quote from a previous and famous Chief Pilot of ours from many moons ago, who sent a scathing Teletype message to a renowned and famous Bell pilot based in Cairns many years ago after being real p**ssed off with the auto RRPM set up on a machine that he tested upon delivery to us.

The message? "it would have real good RRPM upon impact". Go figure.

Learn the basics from the book and worry about the complexities later.

cheers tet

[SASless]

Quick post then got to run....

I chatted with Hueyracer by PM....it was more a language issue than technical....he is working in his second language.

I submitted an earlier post that seems to have gotten lost in the ether....which would have answered several questions posted by Birddog and others.

Since then...several folks have responded with explanations very similar to my lost post.

I will post again when I get back from introducing my almost foster daughter to the nice friendly Army Recruiter....she shows some interest in taking up helicopter flying although I would prefer to see her learning languages, the Law, or most anything else rather than helicoptering!

[spinwing]

Mmmm ...

Toppy ...... a top post! :D

[Helilog56]

Having done literally (tens of) thousands of "full ons" over a 35 year career.....I am appalled that "any instructor" would not nurture and hone a basic survival skill of "hitting the spot" ????

No matter what terrain, in any part of the world, under any condition(s), it is an "ESSENTIAL" survival skill, whether ab initio, or an exprienced pilot.

[Gordy]

I have been reading this thread for a while, but never had time to respond. I think we are getting mixed up between training autos and real life autos. Other than to repeat the excellent words of Sasless--"Ass, tin, ticket", this is all I have to say on this point.

I will share a publication I acquired some years ago entitled "How to crash a helicopter". It gives you the advice that you always wanted to know but were too afraid to ask, for example; "what if I have nowhere to go but into the trees?" (see page 8)

How to crash a helicopter (http://fireheli.com/Files/howtocrashahelicopter.pdf)

Going back to the original question posed by rabidcat:

I just can't seem to accurately judge the spot I am aiming for. I know most everyone has had this problem when they were learning, is it just repetition or is there some other trick?

I have taught the occasional auto in my time, and all I can say is....give it time. There is a ton of excellent advice on this thread, but in reality, it will just "click" one day. You need to read, listen and watch all about autos, and then find what works for YOU. Do not beat yourself up over not hitting the spot right away. Like Sasless, I am not a "numbers" or "theory" type pilot. I see myself more as a kinesthetic type pilot---as in feel the aircraft---trust me, it will come to you one day. I have had students ask me how I did certain things with the helicopter---I cannot explain it, but I can demonstrate so YOU can feel it----and then you can hopefully mimic until you can do it yourself. Hopefully you have an instructor who can do this for you.

Think of it this way----try to explain to me, HOW you balance while riding a bicycle? Some things just come with practice and feel.

[rabidcat]

I am a bit embarrassed to ask this, but what is this "Ass, tin, ticket" bit that you all speak of? I am sure it is quite obvious but let's pretend for a moment that I am just not all that sophistomicated :}.

And once more, thank you all for the help. I am following the thread and absorbing what I can. My instructor ok-ed the chinagraph pen idea... so we are making progress. When weather clears up and I am back to normal flying instead of checkride prep and ground I will give that a try to start.

[Gordy]

"Ass, tin, ticket"

When the proverbial sh1t hits the fan, you have to prioritize your actions:

1. Save your "Ass", as in yourself.

2. Save the "tin", as in the aircraft.

3. Save your "ticket", as in your license.

[topendtorque]

, but what is this "Ass, tin, ticket"


Sasless has inexcusably excused himself just at the moment, according to his latest, 'he is taking his almost foster daughter to meet the nice man at army recruiting'.

And the beautiful 'almost' has NOT been allowed to have it explained to her by all us all straight up and down real nice honest blokes as to why "helicopteuring" is a downright reputable profession.

why don't you ask him why he didn't invite her to meet us.

betcha y' get the same response as above.

[SASless]

Mug of Tea in hand....AFD texting away on her phone....new kitty sacked out on the floor after mooching the Commodore's chow....said Commodore having a royal snit fit about the "evil woman" and her feline consort....back on board here.

Gordy is exactly right about the "Ass, Tin, Ticket" concept of priorities. The sole objective of helicopter flying is for the Pilot and Passengers to be able to hit the bar upon termination of the flying day. One accomplishes that by using the aircraft as a reusable container for important items (said crew and pax). While carrying out that evolution (Navy Term applied to doing something), the concern about whether it is legal or not is of the very least importance. So..."Ass"....get them all home safely with as few aches and pains as possible, "Tin"...preserve the aircraft as long as possible as the Boss Fellah likes for his investment to last as long as possible in the very best of condition....but if needed...use every penny of his money to accomplish save yer "Ass"! As to "Ticket"....worry about arguing with the Crats Agin Aviation after you recover from the "Glad to be Alive" Party. Their snide tidings amount to naught in the scheme of things as compared to "Ass and Tin".

TET described an Auto Revs airtest well enough....and the same general procedure applies to all aircraft. I reference the autorev chart in the Maintenance Manual and calculate the "Target Nr" prior to the flight. Then conduct the flight to ensure I hold a stabilized descent for a full One Thousand-Two Thousand feet of height, with the Collective Lever FULL DOWN (if possible) and record the OAT, Altitude, and Nr. If adjustments are required....do another flight until the target Nr is achieved (or as close as possible) as there might be some slight variation.

As to introducing my AFD to a helicopter pilot.....Forgetaboutit! :=

[Lonewolf_50]

@ coyote:

I realize much of this is remedial, but I respond to you for the benefit of our OP.

In the helicopters I flew, letting Nr Run a bit too high in autorotative descent tended to increase Rate of Descent, a problem which will have to be dealt with in the flare and final pull/recovery. Then again, if you have a very tight landing zone, that may be a good tactic on a given autorotative descent. (Won't get into the esoterics of slips and unbalanced flight, no point at the moment).

This characteristic would make the generic mantra of "you can never have too much Nr" suspect, when you are trying to make the helicopter perform.

Controlling Nr and Airspeed isn't an academic exercise. It is intended to keep the speed and rate of descent manageable as you attempt to hit a safe landing spot, and also to keep your rotor system in the sweet spot so you have the most margin for error. Likewise, with a few extra turns, flight controls being linked to rotor performance, no point losing fore and aft, and lateral, control before necessary as the NR decays in the final input(s).

In support of SASless general comment, letting NR zoom/incr in the flare is generally OK, but only if doing so doesn't detract from your ability to brake the rate of descent in preparation of the final input that allows you to land safely (hopefullyl upright) on the ground/sea where you intended to.

In practice autos, overspeeding NR pisses off the maintenance folks due to added inspections, and I IIRC over time it can shorten component life. That irritates the boss who paid for the bird ...

In a real auto, where the engines or TR quit, there are larger fish to fry than yet another inspection cycle. :cool:

All said and done, I somewhat agree with your reservations on the NR comment, but we probably ought to spell out why, and in what flight regime.

[birrddog]

Sassy, you're name is not Leroy Jethrow Gibbs (http://en.wikipedia.org/wiki/Leroy_Jethro_Gibbs) is it? :p

[SASless]

Harmon's role is loosely based upon my service with that august investigative organization......really! You see the badge he wears.....why I got one of them too....and there the reality differs from the show.

The NCIS has improved greatly since I was there....both by my leaving and from other changes in leadership...funding...and acceptance of modern procedures and policies unlike the time I was there when we were about thirty years behind the FBI. Now days....I would put the NCIS up against the FBI and give some points to boot.

I was around during the time of the Walker Spy Case, the Moscow Embassy Marine Det fiasco, Tail Hook, and some other great examples of how not to do an investigation. The infamous SEAL investigation of Seal Team Six was the ultimate embarassment! Interviewing Hyman Rickover was a hoot too!

During Irangate....I was doing security for the Israeli's when they were meeting with Ollie North and got to meet Netanyahu.

The ultimate thrill was doing a body guard detail for Imelda Marcos.....with one hour notice on a Sunday at Subic Bay!

We had some good times!

Such as loitering around convenience stores in the Washington DC area with Uzi's under our coats.....buying the beer for the pizza after a PSD shift.....and praying some knucklehead showed up with a Saturday Night Special to rob the place while we were buying the beer. It would have been a very sad ending to his crime spree.....when three or four of us opened up on him. It would take longer for the empty brass to quit rolling around than for him to retire from a life of crime!

Ah...but now I am in my rocking chair....thinking of the good ol' days!