Autorotation Help?
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fhvn4d,
With no disrespect to anyone with an opinion to the contrary, the autorotative flare and touchdown landing techniques will vary between any two types of helicopters. You could use R-22 techniques to perform an autorotative landing in a CB300 and will probably live, but the touchdown will not be pretty.
There are two broad types of autorotation techniques people are taught in the CB300. Flare and progressive deceleration. I have, as an instructor and an experimental test pilot, done thousands of touchdown autorotations using both techniques in the TH-55, H300A/B/C, and CB300.....many have been during certification H/V testing. I always use a progressive deceleration as opposed to a flare technique because when performed correctly, you will always touchdown with more main rotor RPM - and that is a good thing. The curious thing is that the progressive deceleration technique is the easier of the two methods to perform. I do not know which technique you use, though your comments suggest a flare technique, but the easiest to use is the progressive decelleration technique.
I have learned over the years that the best way to begin autorotation training is with autorotative descents and power recovery at altitude, far above the ground. Constant airspeed and heading descents, changing airspeed descents, turns, max glide, minimum descent and zero airspeed descents to a specified place on the ground. The last thing is autorotative entries from low, medium and high power conditions. Most intitial students feel confident with all these in less than two hours. They can see and hear changes in main rotor RPM. They know how to enter autorotation, maneuver to a point and change airspeed and RPM to extend or shorten a glide.
Then, and only then, I move to the field. I prefer sod or dirt because few actual autorotions happen over a runway. I demonstrate (student follows through) one straight-in with power recovery then have the student do one with a power recovery. I then demonstrate (student follows through) a straight-in with power recovery. I then move immediately to a straight-in touchdown landing with the student following through. I then ask the student to do one with me assisting with the controls and explaining as I nudge them (when necessary) what I am doing and why I am doing it. The very next autorotation will be only the student manipulating the controls (yes, I stay close) and verbal instructions. Then just the student with no assistance. I have discovered this takes another hour of instruction.
The technique is simple once experienced, but difficult to convey in written word. Descend at recommended speed with collective as full down as possible - at high gross weights, high DA's, or incorrect autorotative main rotor pitch settings you may need to raise the collective slightly. The trick is to keep main rotor RPM as high as possible. Start a slow deceleration so as to not exceed RPM. Increase the rate of decel as you near the ground and pull pitch at about 5 feet - pitch pull altitude varies with gross weight, RPM and DA. A very slight forward cyclic might be necessary as you pull pitch. In zero wind this will result in a landing with one to two lengths ground run. In winds of 10 knots or more less than one length can be expected.
The real trick is to conserve main rotor RPM until the very last. Don't increase collective until the very end and use it in one continuous pull (in the throttle detent of course!). This manuever is easier and requires less pilot compensation than a textbook quickstop. There is no ballooning because you are just doing a slow deceleration. There is no worry about milking RPM during the flare because there is only one continuous pitch-pull just above normal hover height. There is no huge longitudinal cyclic requirement because there is no large flare. There is no worry about hitting the stinger because there is no exaggerated flare.
With no disrespect to anyone with an opinion to the contrary, the autorotative flare and touchdown landing techniques will vary between any two types of helicopters. You could use R-22 techniques to perform an autorotative landing in a CB300 and will probably live, but the touchdown will not be pretty.
There are two broad types of autorotation techniques people are taught in the CB300. Flare and progressive deceleration. I have, as an instructor and an experimental test pilot, done thousands of touchdown autorotations using both techniques in the TH-55, H300A/B/C, and CB300.....many have been during certification H/V testing. I always use a progressive deceleration as opposed to a flare technique because when performed correctly, you will always touchdown with more main rotor RPM - and that is a good thing. The curious thing is that the progressive deceleration technique is the easier of the two methods to perform. I do not know which technique you use, though your comments suggest a flare technique, but the easiest to use is the progressive decelleration technique.
I have learned over the years that the best way to begin autorotation training is with autorotative descents and power recovery at altitude, far above the ground. Constant airspeed and heading descents, changing airspeed descents, turns, max glide, minimum descent and zero airspeed descents to a specified place on the ground. The last thing is autorotative entries from low, medium and high power conditions. Most intitial students feel confident with all these in less than two hours. They can see and hear changes in main rotor RPM. They know how to enter autorotation, maneuver to a point and change airspeed and RPM to extend or shorten a glide.
Then, and only then, I move to the field. I prefer sod or dirt because few actual autorotions happen over a runway. I demonstrate (student follows through) one straight-in with power recovery then have the student do one with a power recovery. I then demonstrate (student follows through) a straight-in with power recovery. I then move immediately to a straight-in touchdown landing with the student following through. I then ask the student to do one with me assisting with the controls and explaining as I nudge them (when necessary) what I am doing and why I am doing it. The very next autorotation will be only the student manipulating the controls (yes, I stay close) and verbal instructions. Then just the student with no assistance. I have discovered this takes another hour of instruction.
The technique is simple once experienced, but difficult to convey in written word. Descend at recommended speed with collective as full down as possible - at high gross weights, high DA's, or incorrect autorotative main rotor pitch settings you may need to raise the collective slightly. The trick is to keep main rotor RPM as high as possible. Start a slow deceleration so as to not exceed RPM. Increase the rate of decel as you near the ground and pull pitch at about 5 feet - pitch pull altitude varies with gross weight, RPM and DA. A very slight forward cyclic might be necessary as you pull pitch. In zero wind this will result in a landing with one to two lengths ground run. In winds of 10 knots or more less than one length can be expected.
The real trick is to conserve main rotor RPM until the very last. Don't increase collective until the very end and use it in one continuous pull (in the throttle detent of course!). This manuever is easier and requires less pilot compensation than a textbook quickstop. There is no ballooning because you are just doing a slow deceleration. There is no worry about milking RPM during the flare because there is only one continuous pitch-pull just above normal hover height. There is no huge longitudinal cyclic requirement because there is no large flare. There is no worry about hitting the stinger because there is no exaggerated flare.
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TFS
There was an Australian pilot working at Weston airport, just outside Dublin that told me that he had tried backwards auto's himself a few times but I don't think that he demonstrates them?
There was an Australian pilot working at Weston airport, just outside Dublin that told me that he had tried backwards auto's himself a few times but I don't think that he demonstrates them?
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Try warming up with a bunch of quickstops just before doing your autos. It will help you focus on allowing the helicopter to start to fall through the flare before leveling and pulling collective.
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Originally Posted by TheFlyingSquirrel
Does anybody out there demonstrate backward autos and then turn them into a normal forward auto again ?
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ok pardon my naievete, but why in the hell would you put the tail towards the ground first>???? who flies backwards at an altitude that makes an auto recoverable???? honestly???? im new but it seems to me that a backwards autorotation is not only dangerous but , dare i say stoooopid...? am i way off? i know i dont have the time or experience to say bully about it, but thats my thinking.. am i way off?
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thx charles... still getting some of the lingo down... LOL.. all i can say is again... WHY BACKWARDS....
one more question all.. my school does not do full down autos, they dont want to be pranging up their only two birds i guess... is this going to be something for me that i should consider going somewhere else when i go for my commercial rating??? i know im going to have to do full downs then...
one more question all.. my school does not do full down autos, they dont want to be pranging up their only two birds i guess... is this going to be something for me that i should consider going somewhere else when i go for my commercial rating??? i know im going to have to do full downs then...
There is no big deal with a backwards auto, it can be useful if everything goes quiet and you have one small landing site ahead...if you do a 360 you may lose it but if you slow down and reverse keeping your heading all you need to do is to know what height to re enter a forward auto and have the speed for a flare and safe landing. I would therefore suggest that they should be taught...surely keeping your one small landing site in view is a huge benefit and getting the roll out from a tight 360 on track is not easy.! Maybe i am missing something or they would be taught!!
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THANK YOU ONE AND ALL
i have to thank everyone who posted with suggestions.. i read each and every one, and i think i put all of them to use at one point or another today.. i hadnt flown in two weeks, so i expected to be rusty, but for whatever reason the helo gods shined on me and i did 4 almost PERFECT autos. ALMOST. they were all landable.... so thank you all for your input... it made a world of difference
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Autos
Rotor & Wing had a very good article a few months back on autos - finishing with flying backwards in the auto. One of those articles I cut out and keep if anyone wants the details PM me.
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Backward auto...
Sorry Mr. Selfish, if this is all just child's play to you, that you don't want to contribute anything usefull, but that's what I'm gonna talk about!
Anyway...
With a 25kt headwind, a lot of altitidue, and your best spot just below your nose, then the 'backward auto' is a very practical method in a 300cb. As already said, a 360 runs the risk of losing the spot completely and disorientation. In fact I did one of these on my private checkride!
It is really only an extension of a vertical autorotoation with a small rearward component..(not more than 5-10kts). Any more than this, and you might find weathervaning kick you round just when you don't want to. It just seems more as you have the wind moving you backwards too.
In fact, rather than straight back, I prefer to do the auto with the spot out of my side window, and have a very slight sideward component to reposition. That way, I have a good view all the way down (no instrument console and pedals obstructing). When I need to, I just use the pedals to turn towards the spot, forward cyclic to regain the speed, and it turns into a normal autorotation.
Whichever method you use, you must absolutely give yourself enough height to regain the speed. Top of the HV diagram is determined based on a hover. But you already have 1500-2000 fpm of descent with this auto. So I always used HV diagram +200 feet minimum (or generally 600')
Flare Height Training
As for training students to judge flare height in a normal auto, I am a believer of the concept of 'skill progression'. I don't see why everyone starts with autos, when the student is not comfortable with descents and rapid descents, descelerations and quickstops. (Just like how instructors chuck 'hover' practice in on day two!)
One method I used was simply to do 'engine-on' 'rapid-descents' with a quick stop at the end. With the 'psychological pressure of an autorotation' absent, we would do the descent with lower and lower collective pitch, and delay the collective pull longer and longer. Eventually, we would be doing an autorotation profile (flat pitch, flare and pull). Then the only thing to do (to make it an autorotation) would be to roll throttle off at the top, and on at the bottom!
cl12pv2s
If you guys are talking about flying backwards in autorotation with a bit of height I’m bored
Anyway...
With a 25kt headwind, a lot of altitidue, and your best spot just below your nose, then the 'backward auto' is a very practical method in a 300cb. As already said, a 360 runs the risk of losing the spot completely and disorientation. In fact I did one of these on my private checkride!
It is really only an extension of a vertical autorotoation with a small rearward component..(not more than 5-10kts). Any more than this, and you might find weathervaning kick you round just when you don't want to. It just seems more as you have the wind moving you backwards too.
In fact, rather than straight back, I prefer to do the auto with the spot out of my side window, and have a very slight sideward component to reposition. That way, I have a good view all the way down (no instrument console and pedals obstructing). When I need to, I just use the pedals to turn towards the spot, forward cyclic to regain the speed, and it turns into a normal autorotation.
Whichever method you use, you must absolutely give yourself enough height to regain the speed. Top of the HV diagram is determined based on a hover. But you already have 1500-2000 fpm of descent with this auto. So I always used HV diagram +200 feet minimum (or generally 600')
Flare Height Training
As for training students to judge flare height in a normal auto, I am a believer of the concept of 'skill progression'. I don't see why everyone starts with autos, when the student is not comfortable with descents and rapid descents, descelerations and quickstops. (Just like how instructors chuck 'hover' practice in on day two!)
One method I used was simply to do 'engine-on' 'rapid-descents' with a quick stop at the end. With the 'psychological pressure of an autorotation' absent, we would do the descent with lower and lower collective pitch, and delay the collective pull longer and longer. Eventually, we would be doing an autorotation profile (flat pitch, flare and pull). Then the only thing to do (to make it an autorotation) would be to roll throttle off at the top, and on at the bottom!
cl12pv2s
Last edited by cl12pv2s; 17th Feb 2006 at 04:28.
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No discredit to your instructor but he/she should be looking at where you look! Im surprised it hasnt been noticed?
It doesnt matter if youre landing a helo or a 747, looking the right place to maxmise the visual cues is essential.
Often, where to look, is not obvious.......so your instructor needs to teach you where and why.
As others have posted you need to get your eyes up to the horizon.
There is a certain 'feel' to where exactly your flare height is, so as has been mentioned, get your instructor to fly down the field at the ideal height so you can start to 'feel' where the ground is.
Lastly, you may find a cadence helps calm the nerves. The more we err, the more the nerves increase and then we get frustrated.
Autos & EOLs are great fun!
So, as you're descending, prior to the flare.....just say to yourself "3.....2.....1......flare"
The 3,2,1 will most likely not be regular at first, it maybe "3......2,1,Flare" but I promise you will find it benefits your judgement and calms any nerves wrt the ground rush!
I promise this very simple technique will work!
One other thing, try as your descending in the glide, stretching out the fingers off your left hand. Please do not let go of the collective, just stretch out the fingers.
I would guess, you'll be surprised at how tight your holding it?
Its a great trick and rediculously effective!
The flare itself is dynamic. It does matter if you've done 20 or 2000, you really dont know how much to flare until you're into it. With experience you'll become better at 'guessing' (with knowledge of weight, wind, density altitude, rrpm etc) but.......the intial cyclic input will always be just "your best guess".
You then of course adjust the attitude to acheive the groundspeed, run-on you desire.
I am very jealous. I know we all remember those days and the joy of learning to fly a helicopter.......Have fun and enjoy it.
It doesnt matter if youre landing a helo or a 747, looking the right place to maxmise the visual cues is essential.
Often, where to look, is not obvious.......so your instructor needs to teach you where and why.
As others have posted you need to get your eyes up to the horizon.
There is a certain 'feel' to where exactly your flare height is, so as has been mentioned, get your instructor to fly down the field at the ideal height so you can start to 'feel' where the ground is.
Lastly, you may find a cadence helps calm the nerves. The more we err, the more the nerves increase and then we get frustrated.
Autos & EOLs are great fun!
So, as you're descending, prior to the flare.....just say to yourself "3.....2.....1......flare"
The 3,2,1 will most likely not be regular at first, it maybe "3......2,1,Flare" but I promise you will find it benefits your judgement and calms any nerves wrt the ground rush!
I promise this very simple technique will work!
One other thing, try as your descending in the glide, stretching out the fingers off your left hand. Please do not let go of the collective, just stretch out the fingers.
I would guess, you'll be surprised at how tight your holding it?
Its a great trick and rediculously effective!
The flare itself is dynamic. It does matter if you've done 20 or 2000, you really dont know how much to flare until you're into it. With experience you'll become better at 'guessing' (with knowledge of weight, wind, density altitude, rrpm etc) but.......the intial cyclic input will always be just "your best guess".
You then of course adjust the attitude to acheive the groundspeed, run-on you desire.
I am very jealous. I know we all remember those days and the joy of learning to fly a helicopter.......Have fun and enjoy it.
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I demonstrate 'backward' autos, but as previously stated it is vital that you have sufficient altitude. (why only with a 25 knot headwind?) It really helps actually in gaining an understanding of sight pictures and setting the correct nose attitude to obtain the correct airspeed for the recovery. I teach in the 300, but have a fair amount of R22 time.
It is extremely important to develop a feel for the aircraft, rather than flying set numbers. Once you can recognise when the pitch of the nose is right to give you the correct airspeed then life will become much easier. Try not to focus too much on the airspeed indicator. Look at the trend of what it is doing and make slight adjustments as required.
One thing that I do as an instructor is to cover up the airspeed indicator with my hand and read out the airspeed as we descend. Therefore there is no point in the student looking inside, because there's nothing to see.
On the entry keep your eyes outside and keep the nose attitude constant, by using cyclic inputs. Don't let it drop as you will reduce your rotor RPM real fast.
Really listen to the transmission. It will tell you what the rotor RPM is doing. If the 'whine' gets louder you are gaining RPM, if it is getting quieter (or the horn comes on in the R22), then you are losing it. Collective inputs are made correspondingly. RPM goes up = collective goes up, RPM going down = collective going down. This becomes much more important when doing 90's and 180's.
Keep a visual lock on your spot. Look where you're going. The more time your eyes are outside, the easier it will become.
As far as flare height goes take great note of Rich Lee's post about the 300. DO NOT TRY AND FLY THE 300 LIKE AN R22!! Start the flare much higher and be more progressive.
Keep at it and it'll click. After a while it becomes a lot of fun trying to hit the same spot consistently from different altitudes and airspeeds.
It is extremely important to develop a feel for the aircraft, rather than flying set numbers. Once you can recognise when the pitch of the nose is right to give you the correct airspeed then life will become much easier. Try not to focus too much on the airspeed indicator. Look at the trend of what it is doing and make slight adjustments as required.
One thing that I do as an instructor is to cover up the airspeed indicator with my hand and read out the airspeed as we descend. Therefore there is no point in the student looking inside, because there's nothing to see.
On the entry keep your eyes outside and keep the nose attitude constant, by using cyclic inputs. Don't let it drop as you will reduce your rotor RPM real fast.
Really listen to the transmission. It will tell you what the rotor RPM is doing. If the 'whine' gets louder you are gaining RPM, if it is getting quieter (or the horn comes on in the R22), then you are losing it. Collective inputs are made correspondingly. RPM goes up = collective goes up, RPM going down = collective going down. This becomes much more important when doing 90's and 180's.
Keep a visual lock on your spot. Look where you're going. The more time your eyes are outside, the easier it will become.
As far as flare height goes take great note of Rich Lee's post about the 300. DO NOT TRY AND FLY THE 300 LIKE AN R22!! Start the flare much higher and be more progressive.
Keep at it and it'll click. After a while it becomes a lot of fun trying to hit the same spot consistently from different altitudes and airspeeds.
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(why only with a 25 knot headwind?)
Of course, it can be done at any windspeed!!
I too have used instrument covers to help students 'get a feel' for the aircraft in autos. First time was when I was teaching autos, and the student kept on coming in too slow...after a couple, I realised that the ASI was reading wrong (10kts high), and he was relying on this too much...so the next time I brought the cover!
cl12pv2s
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One thing.
I noticed you mentioned ballooning... Now i am not an expert on the topic but i did had some major issues controlling RPM at the end of the auto and flaring, and my instructor said this had been made more difficult because of my weight... I was near the top of the limits in RPM and sometimes a bit over them and everytime i flared (i usually don't touch the collective at the flare until i bleed some airspeed) but in my case i balooned and the RPM got way high, and if i pull collective i will baloon even more. So the way i could control RPM was by having the RPM on almost the bottom of the green (WELL WITHIN LIMITS), and when i initiate the flare i don't touch collective, and i baloon a bit. I also come in a bit slower than usual but within limits (ALLWAYS WITHIN POH LIMITS), and at then end when i bleed airspeed, i pull a bit collective to stop forward movement, then level and then cushin.
However my instructor did not noticed this until i ask him to demonstrate this to me again, cause i was having lots of trouble, and when he tried it he went (WWOOOAA) that was unexpected. And we both mastered a techniq that was within limits at all times but mostly refine the timing of my reactions for my weight, and we tried this with different fueling to get a feel for reaction, but mostly in the top of the limits the auto felt very very different than from the lower part... The thing is the flare and balooning with high weights.
I know i will get a lot of rocks here saying "YOU HAVE TO FEEL THE AUTO, INDEPENDANT OF THE WEIGHT" well that's true, but i was just a beginer following instructions from an instructor expecting something to happen, and it did happened but happened completely different from what he was expecting, so he blamed it on me, when it was on the timing... So we fixed this and then experimented with diferent weights (fuel) to get a feel for reactions.
So what i recommend is DO one auto. Then let the instructor do one, and then do one together. And then try one. And so and so.. Its practice...
I think you can make your goal if you stop worring on how fast you need to make the test; You'l be ready sooner than you think...
RELAX...
HAVE FUN....
AND ENJOY.....
And you will make it... I swear...
However my instructor did not noticed this until i ask him to demonstrate this to me again, cause i was having lots of trouble, and when he tried it he went (WWOOOAA) that was unexpected. And we both mastered a techniq that was within limits at all times but mostly refine the timing of my reactions for my weight, and we tried this with different fueling to get a feel for reaction, but mostly in the top of the limits the auto felt very very different than from the lower part... The thing is the flare and balooning with high weights.
I know i will get a lot of rocks here saying "YOU HAVE TO FEEL THE AUTO, INDEPENDANT OF THE WEIGHT" well that's true, but i was just a beginer following instructions from an instructor expecting something to happen, and it did happened but happened completely different from what he was expecting, so he blamed it on me, when it was on the timing... So we fixed this and then experimented with diferent weights (fuel) to get a feel for reactions.
So what i recommend is DO one auto. Then let the instructor do one, and then do one together. And then try one. And so and so.. Its practice...
I think you can make your goal if you stop worring on how fast you need to make the test; You'l be ready sooner than you think...
RELAX...
HAVE FUN....
AND ENJOY.....
And you will make it... I swear...