Check Collective??

[RockyMountainPilot]

I was looking back on the thread to see exactly how the thread got to this point, and things were not exactly making sense. Until I noticed..

 

This post has been edited by Mikemv: Yesterday, 09:41

This post has been edited by Mikemv: Yesterday, 10:00

This post has been edited by Mikemv: Yesterday, 10:07

This post has been edited by Mikemv: Yesterday, 10:10

This post has been edited by Mikemv: Yesterday, 10:12

 

I am not trashing anybody here, but when the core comments and discussion points have been removed anybody who is trying to follow the thread will be confused and think RockyMountainPilot is a lunatic.

 

A person changing their story days later should make anybody question the validity of any other post. Make a statement, stick with it. If views change, then man up and admit it. I was wrong once in the late 80's when I thought that the big hair bands would never go away.

 

 

Thanks for pointing that out.

 

 

But we are talking about practice autorotations. At least we were. If you want to be a test pilot and overspeed it during the real thing, knock yourself out. Here is one reason not to overspeed it: the flight manual. You gotta do what you gotta do, but to say you are going to overspeed automatically doesn't make sense to me.

 

We were talking about autorotations. I mention what I would do in a real engine out scenario. Why is this not on topic?

 

The FARs allow any limitation to be exceeding in the interest of safety. And the flight manual isn't responsible for keeping people safe.

[helonorth]

Well, we were talking about maintaining RPM during practice autorotations. Anyway, when the engine quits, you do whatever you have to do. I couldn't care less about regulations or limitations. But you have your own ideas (different than the people that built it) about what to do, and that's my problem. And until you know the machine better than the people that built it,

I would recommend following the manual.

Edited September 7, 2009 by helonorth

[RockyMountainPilot]

Well, we were talking about maintaining RPM during practice autorotations. Anyway, when the engine quits, you do whatever you have to do. I couldn't care less about regulations or limitations. But you have your own ideas (different than the people that built it) about what to do, and that's my problem. And until you know the machine better than the people that built it,

I would recommend following the manual.

 

"Because they said so" isn't good enough for me either. A good reason has sound science, physics, or statistics to back it up. And guess what. The people who built the helicopter aren't sitting behind the controls when the engine quit. I am, so I get to do whatever I feel is best to keep people from coming to harm. And having more energy in the rotors at the bottom of the flare is going to do just that.

 

Again, the manual is not the one who is responsible for human lives. If you have a good reason other than "I said so", or "they said so" etc etc, please say it. Otherwise, I will fly in a manner that is the safest possible, and that if that includes exceeding limitations to cope with an emergency, then so be it.

[nikon858]

neverquestionme,

 

Please point out where I said I wouldn't teach students rpm control....I didn't, I simply teach my initial students to set the collective and pedals prior to entering the flare, then control rpm with cyclic only......I thought I said that fairly clearly earlier....are you saying there's something wrong with how I'm teaching??? I will gradually teach students more and more as they progress, but the way you say things need to be tought, well, do you give all three controls to your student the first time their learning to hover??? I don't it's not how I was taught either....one control at a time, and progress up to all the controls......is teaching just the autorotation glide first not proper either because it isn't the whole maneuver?? NO! It's a progression in learning, I'm really not sure why your arguing with me.....please explain.

[helonorth]

"Because they said so" isn't good enough for me either. A good reason has sound science, physics, or statistics to back it up. And guess what. The people who built the helicopter aren't sitting behind the controls when the engine quit. I am, so I get to do whatever I feel is best to keep people from coming to harm. And having more energy in the rotors at the bottom of the flare is going to do just that.

 

Again, the manual is not the one who is responsible for human lives. If you have a good reason other than "I said so", or "they said so" etc etc, please say it. Otherwise, I will fly in a manner that is the safest possible, and that if that includes exceeding limitations to cope with an emergency, then so be it.

It's not me saying this. It's The people that built the helicopter that are telling you this. I'm just relaying it to you. And I really don't think what you are doing is really safe at all. It's your decision, you can do what ever you want when the engine quits. I will say this though, you would never get near any

helicopter I owned or operated, as you have publicly stated you would overspeed it. I will try to bring myself, my passengers and the aircraft back undamaged if the engine quits. That's what is expected of me. The ironic thing is that your position is the only one without any science (or anything else) behind it!

Edited September 8, 2009 by helonorth

[Mikemv]

I was at the airport today running up my EC120 and checked the R22 flight manual. I determined that at 125% rotor RPM, the main rotor will be turning 637.5 RPM. Did anyone mention that the rotor tach only indicates to 116 in the R22? Must be some other aircraft that goes to 125%? How fast is the tail rotor and tail rotor drive shaft turning? When do you lose tail rotor control due to twisted or broken drive components? And of course, being that it is a real emergency, you want to disregard your training (do not use any skill you have) and try something unproven and unaccepted industry wide because someone who has not done one, ten or a hundred of these tells you to.

 

Also, everyone please realize that the nose high flare attitude necessary to achieve 125% rotor RPM will need to be lowered to a landing attitude and this change will not sustain 125% for cushioning!

 

Handle emergencies the way you have been trained! Do not accept overspeeding on someones uneducated, untested, untried theory that is against all safety standards! Call the Robinson Factory or any manufacturers school and ask them about this 125% intentional overspeed and get your info from a valid source!

 

The answer to the test question is that the "Collective" controls rotor RPM!!!! The cyclic may change it in a flare but Primary control is the Collective! Do not believe me because I deleted portions of the previous posts. Ask any FAA Inspector, DPE, CFI, or just read the book!

 

Please, everyone rely on your training, fly the aircraft all the way to the ground as you know how to.

 

 

Best to All, MikeMV

[PhotoFlyer]

I REALLY don't want to have to close this topic, since it could become a very informative discussion. Please don't let this degrade into a name calling tirade.

[RockyMountainPilot]

It's not me saying this. It's The people that built the helicopter that are telling you this. I'm just relaying it to you. And I really don't think what you are doing is really safe at all. It's your decision, you can do what ever you want when the engine quits. I will say this though, you would never get near any

helicopter I owned or operated, as you have publicly stated you would overspeed it. I will try to bring myself, my passengers and the aircraft back undamaged if the engine quits. That's what is expected of me. The ironic thing is that your position is the only one without any science (or anything else) behind it!

 

Why is it not safe? You have more energy in the rotor system, it gives you more time to react, and could be the difference wrecking the whole helicopter and someone getting hurt or killed and just damaging some replaceable components. More energy in the rotor system is the physics you fail to see in why I would do such a thing. I thought it was obvious that more rotor RPM meant more energy. More energy means more time to react to problems.

 

Many real autorotations end up with wrecked helicopters and injured occupants despite a perfect landing zone. And look at how many practice autorotations end up with wrecked helicopters and injured or killed people! More helicopters are wrecked in practice autorotations then there are engine failures. If so many pilots and CFI's are wrecking helicopters during a controlled scenario, then it is easy to understand why so many real engine failures end up with damage.

 

And I never said that you shouldn't try and bring it back undamaged. Great if you can. But in a real scenario, in all likelihood, you are approaching an LZ that you have not done any recons on, you have no idea what kind of surface you will be setting down on, and you have no way to go around it you realize kids are running across the field. That is not the time to wish you have more RPM. But if I have a nice big piece of pavement with no obstacles around, then yeah, I will try and set it down without overspeeding the rotor. However, where I fly, that is highly unlikely.

 

 

I was at the airport today running up my EC120 and checked the R22 flight manual. I determined that at 125% rotor RPM, the main rotor will be turning 637.5 RPM. Did anyone mention that the rotor tach only indicates to 116 in the R22? Must be some other aircraft that goes to 125%? How fast is the tail rotor and tail rotor drive shaft turning? When do you lose tail rotor control due to twisted or broken drive components? And of course, being that it is a real emergency, you want to disregard your training (do not use any skill you have) and try something unproven and unaccepted industry wide because someone who has not done one, ten or a hundred of these tells you to.

 

Also, everyone please realize that the nose high flare attitude necessary to achieve 125% rotor RPM will need to be lowered to a landing attitude and this change will not sustain 125% for cushioning!

 

Handle emergencies the way you have been trained! Do not accept overspeeding on someones uneducated, untested, untried theory that is against all safety standards! Call the Robinson Factory or any manufacturers school and ask them about this 125% intentional overspeed and get your info from a valid source!

 

The answer to the test question is that the "Collective" controls rotor RPM!!!! The cyclic may change it in a flare but Primary control is the Collective! Do not believe me because I deleted portions of the previous posts. Ask any FAA Inspector, DPE, CFI, or just read the book!

 

Please, everyone rely on your training, fly the aircraft all the way to the ground as you know how to.

 

 

Best to All, MikeMV

 

I said I would flare to get as much as I could. If I could get 125%, I would take it.

 

Let's look at the physics behind overspeeding the rotor during autorotation.

 

Drivetrain: The main rotor is being spun by the air and is turning the tailrotor. The tailrotor only needs to counter the drag of the transmission wish is a small amount of torque compared to when in a hover under power. The tailrotor is almost at neutral pitch, so you aren't really putting any significant torque into the system at all. The worst thing you will encounter is a possible resonance of the drive shaft as you approach the 3rd sinusoidal wave progression.

 

Main Rotor: The R22 is a good example. The R22 rotor blade tips will encounter supersonic airflow during an excessive overspeed. At this point, the drag on the rotor blades will prevent any further overspeed. The rotor system won't come apart, but may encounter some damage to parts. You can ask Pat Cox if you doubt this.

 

Energy: Kinetic Energy is 1/2 Mass times Velocity squared. If you increase the RPM by 10%, you get more then 20% more energy. 20% overspeed is 44% more energy.

 

When you are in the flare, you are causing the blades to cone up which causes the RPM to increase because you reduce the distance from the hub to the blades center of mass. Conservation of angular momentum requires the blades to increase in speed. When you push the nose over to level the ship, the blades are less coned, the blades center of mass moves out, and the RPM decreases. However, you have the same amount of energy still in the blades. You no longer have the airflow going through and driving the rotor, so you immediately start to lose energy, but it is still the same amount in the flare as it is when you level the ship.

 

Plenty of CFI's and students have tested the high RPM limits of probably every most helicopter flying. Many Robbies are oversped well above the upper redline daily, and never reported. Usually, the flat spots on the spindles are what gives it away.

 

No one ever said that the collective is not the primary control. However, it is not the only control. If you are sitting in a helicopter on the ground with the engine off, no amount of collective will get those blades to spin. LOL The engine, the cyclic, and even the pedals impact RPM. If my low rotor RPM horn comes on in flight and all I do is lower collective, it will only help me if there is a constant throttle setting. On helicopters with a correlator, the manifold pressure will drop and the rpm may not increase at all, or could even decrease. So, throttle is also required. If you can't afford to lose any altitude, you can pitch the nose up with the cyclic to hold altitude why you roll the throttle on.

 

So, it is very important that a pilot needs to use all the controls available in unison and that they know the relationships between them.

[nikon858]

rockymountain

 

"Drivetrain: The main rotor is being spun by the air and is turning the tailrotor. The tailrotor only needs to counter the drag of the transmission wish is a small amount of torque compared to when in a hover under power. The tailrotor is almost at neutral pitch, so you aren't really putting any significant torque into the system at all. The worst thing you will encounter is a possible resonance of the drive shaft as you approach the 3rd sinusoidal wave progression."

 

At what rpm will you get the resonance in the TR driveshaft? They told us at the factory, just can't recall what rpm it was....and I know you say thats the worst that can happen, but if that does happen it will destroy your tailboom (that part I remember) lose the tailboom, and no matter how hard you pull the cyclic aft your CG is gonna be so out of whack your gonna nose dive into the ground.

 

The only other thing you said I don't agree with, is leveling the ship and not losing rpm...maybe I misunderstood you, but from what I read you think you won't lose rpm when you level the ship after the flare....I've always lost ~10% in a 22 after leveling.

 

I have to say, when I got my ppl, I too thought more rpm=safer landing....but with what I've come to learn I know thats not true....like mikev said, do it as you've been trained...if you screw up and overspeed, well like you said, the ship has already given up....but don't overspeed intentionally.

[RockyMountainPilot]

rockymountain

 

"Drivetrain: The main rotor is being spun by the air and is turning the tailrotor. The tailrotor only needs to counter the drag of the transmission wish is a small amount of torque compared to when in a hover under power. The tailrotor is almost at neutral pitch, so you aren't really putting any significant torque into the system at all. The worst thing you will encounter is a possible resonance of the drive shaft as you approach the 3rd sinusoidal wave progression."

 

At what rpm will you get the resonance in the TR driveshaft? They told us at the factory, just can't recall what rpm it was....and I know you say thats the worst that can happen, but if that does happen it will destroy your tailboom (that part I remember) lose the tailboom, and no matter how hard you pull the cyclic aft your CG is gonna be so out of whack your gonna nose dive into the ground.

 

The only other thing you said I don't agree with, is leveling the ship and not losing rpm...maybe I misunderstood you, but from what I read you think you won't lose rpm when you level the ship after the flare....I've always lost ~10% in a 22 after leveling.

 

I have to say, when I got my ppl, I too thought more rpm=safer landing....but with what I've come to learn I know thats not true....like mikev said, do it as you've been trained...if you screw up and overspeed, well like you said, the ship has already given up....but don't overspeed intentionally.

 

Nikon,

 

I said you have the same energy, not RPM. You lose RPM when you level the ship because you are no longer coning the blades as much as you were in the flare. So, your center of mass moves outward and the rotors slow, but the energy is the same.

 

You will not lose your tailboom during an overspeed. If you did, most every R22 would have done so. LOL The factory has oversped an R22 to the point the blades can't go any faster and although it did damage some of the rotating components as would be expected, the helicopter did not self destroy.

 

You can do like you trained if everything goes just like you trained, but in the real world of flying, you do not have engine failures over nice paved runways or open fields. The thing about training is that it is suppose to teach you to apply your experience to whatever situation arises. My experience is that if I think there might be any issues with the touchdown, I want the most rotor RPM that I can get. So, in essence, I am doing exactly how I was trained, which is to think beyond the training.

[NeverQuestionMe]

I was at the airport today running up my EC120 and checked the R22 flight manual. I determined that at 125% rotor RPM, the main rotor will be turning 637.5 RPM. Did anyone mention that the rotor tach only indicates to 116 in the R22? Must be some other aircraft that goes to 125%? How fast is the tail rotor and tail rotor drive shaft turning? When do you lose tail rotor control due to twisted or broken drive components? And of course, being that it is a real emergency, you want to disregard your training (do not use any skill you have) and try something unproven and unaccepted industry wide because someone who has not done one, ten or a hundred of these tells you to.

 

Also, everyone please realize that the nose high flare attitude necessary to achieve 125% rotor RPM will need to be lowered to a landing attitude and this change will not sustain 125% for cushioning!

 

Handle emergencies the way you have been trained! Do not accept overspeeding on someones uneducated, untested, untried theory that is against all safety standards! Call the Robinson Factory or any manufacturers school and ask them about this 125% intentional overspeed and get your info from a valid source!

 

The answer to the test question is that the "Collective" controls rotor RPM!!!! The cyclic may change it in a flare but Primary control is the Collective! Do not believe me because I deleted portions of the previous posts. Ask any FAA Inspector, DPE, CFI, or just read the book!

 

Please, everyone rely on your training, fly the aircraft all the way to the ground as you know how to.

 

 

Best to All, MikeMV

 

*just in case I forget what was said and can't go back later*

 

 

Just after I was finished parking my Citation X and was walking to my Ferrari, my assistant told me that there was more talking about this topic still.

 

Attached is a photo of the motor and rotor tach.

Not quite 116%, but who's really counting.

The amount of rotor RPM does have to do with the nose attitude, but it also has to do with the rate at which the collective is pulled aft and it also has to do with the airspeed.

 

I would really think that all parties involved in not only this conversation but aviation in general should review the books and procedures. Just because my great grandmother has been driving for 95 years does not mean she knows what she is doing.

 

A summary so far...

 

two trains of thought.

Learn how to auto correctly

Chase the needle

 

There you go.

[NeverQuestionMe]

rockymountain

 

At what rpm will you get the resonance in the TR driveshaft? They told us at the factory, just can't recall what rpm it was....and I know you say thats the worst that can happen, but if that does happen it will destroy your tailboom (that part I remember) lose the tailboom, and no matter how hard you pull the cyclic aft your CG is gonna be so out of whack your gonna nose dive into the ground.

 

 

60 to 70 percent. That's the yellow part on the tach.

[NeverQuestionMe]

I REALLY don't want to have to close this topic, since it could become a very informative discussion. Please don't let this degrade into a name calling tirade.

 

 

To be honest, I think you probably should not only close it but delete the whole thing if possible.

 

The topic is way off on a tangent, and some of the posts have been edited to a point where the thread makes no sense anymore.

 

Just my two cents though, I think it is both informative and entertaining.

[nikon858]

60 to 70 percent. That's the yellow part on the tach.

 

no...the TR driveshaft resonance that were talking about is from high speeds..

 

 

"The amount of rotor RPM does have to do with the nose attitude, but it also has to do with the rate at which the collective is pulled aft and it also has to do with the airspeed."

 

What are you talking about??? Collective aft? We've already established that all the controls determine rotor rpm........and you never answered my question.

Edited September 9, 2009 by nikon858

[RkyMtnHI]

I try to glean the good in all topics..

 

This one has encouraged me to add a new line to my CFI job application. It is as follows:

 

"Do you post on any online forums? If so, what screen name do you use?"

 

 

:-)

 

dp

[rotorrodent]

Also, is checking the collective just a part of the power recovery and if we are in a real live auto, would it help me to do it?

Thanks as always..and please know...once I get my ppl, I will share a piece of it with all of you.

 

Everyone wanting a good laugh? When I was a brand new student doing auto's for the first time, this is what I was doing. When initiating the auto, the instructor told me to check the collective. So I checked it, looked fine to me. Then the main rotor would spool up some towards the top of the green, he would say, "check collective". I did. Looked ok to me.

 

After the flight, we debriefed the "check collective" callout (if you will). Seems I missed this explanation somewhere along the way. See, I thought check collective meant to "look" at it and make sure that it was down!

 

Since that time, auto's haven't been any drama.

 

It is really fun being the naive "new" guy, or better yet, "don't I feel foolish"!

 

cheers

 

Rotorrodent

[TimW68]

Hmmm, do I dare. Ok every situation calls for a different action by the pilot, I believe that is why we are trained to handle auto's the way we are. Some require longer glides some require shorter, some even substantial maneuvering under 100 ft. Obstacles on the ground i.e people, obstructions, level ground etc. are going to be something you have to adjust to when you get there. I don't think anybody was stating that you need to overspeed at 2000 ft. agl, but if the choice is to overspeed 15 ft. above the ground by 10% to keep from killing someone, a dynamic rollover, or totaling the aircraft for whatever reason because you didn't have that extra 2 to 5 seconds to set it down properly, makes no sense at all. To much is being taken out of context, in a situation where the LZ supports a safe landing there is no reason to overspeed, and I give Rocky enough credit to believe he would only use this extra energy because it's absolutely necessary. Now lets go way back and discuss a student pilot, with under 100 hours dealing with engine failure getting the bird and yourself down in one piece, overspeed or not is an accomplishment. Before your to hasty with judging that statement keep in mind we are rarely if ever taught full downs at that level. I'm not sure exactly what an overspeed could rack up in costs but I'm sure it's less than a life lost, a balled up machine, or even spread skids and a shortened tail boom . Just my 2 cents.

[Goldy]

I try to glean the good in all topics..

 

This one has encouraged me to add a new line to my CFI job application. It is as follows:

 

"Do you post on any online forums? If so, what screen name do you use?"

 

 

:-)

 

dp

 

 

dp- Yes, I do...and the name is Goldy !!! jk

 

The other post about seeing 60 or 70% main rotor rpm....ummmm...just so the students know....you're already dead at that %.

 

Goldy

Edited September 11, 2009 by Goldy

[NeverQuestionMe]

dp- Yes, I do...and the name is Goldy !!! jk

 

The other post about seeing 60 or 70% main rotor rpm....ummmm...just so the students know....you're already dead at that %.

 

Goldy

 

The RPM that is being discussed at 60-70% is tail rotor in the last few posts.

[Whistlerpilot]

Kind of interesting reading this post. Hope we can all play nice here. I enjoy hearing everyones different opinions.

 

Back to the original post: It seems that "check collective" is interpreted by most to mean check your RRPM prior to the flare. This RRPM info is good to know and used to manipulate the collective to maintain desired RRPM prior to flaring. This info can also be used to change the amount and timing of the flare to keep RRPM optimal to cushion for landing after the flare.

 

No one mentioned the term 'collective check' which is a little bit of blade pitch applied at the end of the flare to aid the leveling of the helicopter. This procedure allows the helicopter to be levelled with a smaller forward cyclic movement. A big forward push to level will unload the disk, reduce RRPM and excelerate that last crucial descent to ground contact. Of course if the 'collective check' is dragging down RRPM then it's likely miss timed with the flare.

 

I like the 'collective check' when doing full down autos but it isn't universally used. Seems most folks try to flare the R22 gently to avoid the overspeed and just accept the run on. In a real life engine failure I suspect I would flare pretty hard to stop at my spot and use the 'collective check' to help level as well as not overspeed. I sure hope in real life I would do this well so I end up 8 feet up, level, with little to no airspeed, and RRPM tip top of the green to cushion the touch down.

 

Another important point: High inertia rotor systems and low inertia rotor systems behave differently in autorotation. Because of that there is not a one size fits all procedure. What works well in an R22 is not quite what I do in the Jet Ranger! The low inertia systems are way more sensitive to disk attitude changing RRPM for example. I had a student a few days ago go from extremes of low to high RRPM just by chasing his airspeed in a H269. The high inertia systems are a delight to full down. I miss the Bell 47 and 206 now that I'm mostly instructing on the 269 and R22.

 

Here is a good video on autos put out by the Bell Factory Trainers. Well worth the time despite being dated.

 

 

Cheers,

 

Eric

[ABarnes]

How about the perspective of someone with no flight time other than a discovery flight?

 

I think a statement along the lines of "screw the helicopter, it's already given up on me" is foolish. Granted, you have to adapt to different variables that may come up but to immediately say "screw the helicopter" in an engine out situation doesn't make sense. You are IN the helicopter. If the helicopter suffers further mechanical failure because you exceed manufacturer recommendations and don't follow their procedures.... well, the helicopter AND potentially you suffer. "Because someone said so"??? Not just someone, the manufacturer. The people that built the helicopter. The people that flight tested it for several years most likely. The people that pushed the helicopter toward, to, and past the limits to establish where those limits are. Those are the people that said "Don't go past this point."

 

So during a real engine out landing you put your aircraft down. During your needle pegged overspeed you damage some components in the rotor system, the engine, wherever it may be. Potentially thousands of dollars in damage if not tens of thousands. But hey, you're all safe right? You saved the day? yaaaaay. Now how's your boss going to feel when the engine out was caused by something as simple as vapor lock and there was no actual damage to the engine? Or a clogged fuel line? You think he'll be happy with the "screw the helicopter" attitude?

 

 

And as a totally unexperienced future pilot, I would think that perhaps (at least for a R22), safety notice 36 would be applicable even though it's titled "Overspeeds during liftoff" It specifically mentions that overspeeds can cause tail rotor shaft vibrations which led to IMMEDIATE failure of the shaft and tailcone. Normally the shaft vibration is controlled by a damper bearing. "However, damper is not effective above 120% RPM" Now, to me, that basically says that exceeding 120% is basically risking a catastrophic loss of control. Like I said, SN-36 is titled "...during liftoff" so perhaps it doesn't apply to landing. But to me, a danger limit of 120% applies in any situation by the wording in that SN.

 

The very next SN? "SN-37 - EXCEEDING APPROVED LIMITATIONS CAN BE FATAL"

 

I really think this one is directly applicable to this discussion.

 

"Many pilots do not understand metal fatigue. Each time a metal

component is loaded to a stress level above its fatigue limit, hidden

damage occurs within the metal."

 

"It will also occur rapidly in rotor

system components due to the high centrifugal force on the blades and

hub. Damaging fatigue cycles occur with every revolution of an overload

drive shaft or rotor blade."

 

If a pilot exceeds the power or airspeed limits on a few occasions without

failure, he may be misled into believing he can safely operate at those high

loads. Not true. Every second the limitations are exceeded, more stress

cycles occur and additional fatigue damage can accumulate within the

metal. Eventually, a fatigue crack will begin and grow until a sudden

failure occurs. If the pilot is lucky, the part will have reached its approved

service life and be replaced before failure. If not, there will likely be a

serious or fatal accident.

 

 

Personally, I think I'll stick with the people that made the helicopter. Yeah, just "some guy" I guess.

 

 

And, once again, I have no appreciable experience. But I like to think I've got a decent head on my shoulders. So everything I typed could be wrong or not even applicable.

 

Keep the big spinning dohickey up!

[ABarnes]

Also, in regards to the original post. I think what is most important is good communication between the student and the instructor. It's apparent that many people here have different ideas what "check collective" means. Your best bet is to ask your instructor EXACTLY what he means by that. I would think that should have been your first question when you heard that. Then there's no confusion and you're clear on what the instructor is expecting.

[spubar44]

not sure where this thread is going, but in regards to exceeding the rotor RPM's. As a pilot in training and having just started doing straight in auto's, I also asked my instructor, why not exceed the rrpm if the engine quit? Well, since he attended the robinson school, and asked the same thing, he told me that there are bearing on the rotor that allow the blades to feather. The exceeded rrpm around 118% starts to put undue stress on these bearings, which could and may lead to bearing failure. So what, the engine quit, it is alerady screwed you say! Well, if during the auto, the bearings fail and seize, this in turn prevents you from being able to feather the blades if required to complete a steady and safe landing. So to keep a bad situation from getting worse, you don't want to exceed the rrpm. Thus, you have lift or CHECK collective to prevent the rotor over speed. Thanks for listening.

Edited September 11, 2009 by spubar44

[PhotoFlyer]

I'm not sure where the thread is going either. I don't mind the heated discussion (thats why this has gone unlocked so long) but everyone is just going around in circles.

 

Whistlerpilot brought up an excellent point, that a collective check is a slight raise in collective to aid leveling the helicopter. When applied correctly it can also substantially reduce or eliminate ground run at the end of an auto. I suspect (and have thought from the beginning) that this is what the OP's CFI meant by a collective check.

 

Next: Limitations are established for normal flight operations. They are not (contrary to apparent popular belief) in the manual to restrict what a pilot can do in an emergency. In an emergency a pilot can (and should) do WHATEVER he needs to do to SUCCESSFULLY land the aircraft. Successfully DOES NOT mean safely, it means a landing that everybody can walk away from. The aircraft might be on it's side in several pieces, but if everybody walks away it was successful. I will be the first person to say that the ideal situation would be landing with no damage to the aircraft or persons, but that is not always an option.

 

The reality is that using a helicopter to its full potential requires operating in situations (within limits) that would require exceeding limits if an emergency occurred. That's just the way it is. If you don't like that, then don't do those jobs that require you to be in a hazardous situation.

 

I am not going to close the thread right now, but this is the LAST opportunity to stop arguing and start discussing. This is a forum where opposing viewpoints are welcome and healthy discussion is encouraged. Please help keep it that way. I don't like closing topics.

[helonorth]

ABarnes, you are exactly correct, in my opinion. Operate the machine as designed and intended.

We cannot pick and choose which limitations we want to exceed in the name of "safety". One thing I

have learned in 2500 hours: follow the rules, all the time. I'm not saying fly into wires to avoid an overtorque. Do what you have to do to meet the extent of the emergency. An attitude of "I know better" is one of the

most dangerous things in aviation. Thanks for the excellent post. We may have been arguing, but what

some posters are trying to put across will kill you. I have seen it happen. Oh, I think you're probably gonna make a damn good pilot.

Edited September 11, 2009 by helonorth