0 G flight condition

fara

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Sorry, my translator knows not "zoom clim". Can you explain to me ? Thank you
The climb where you build extra horizontal speed and then pull the stick back slightly to pitch upwards and change excess speed to altitude
 
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chrisk

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Sorry, my translator knows not "zoom clim". Can you explain to me ? Thank you
Watch the video starting at 52 seconds and you will see a zoom climb and why you should be careful with them. I can't find the original video on line, but I show all of my students this accident before they take their check ride.
 

hillberg

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You do not need the "zoom" you just need forward cyclic input in forward flight -

cruse flight, Panic moment, then a sudden brisk forward cyclic = low G.

Look at the sport copter doing loops - brisk sudden +G - now do the same with forward cyclic . . .brisk sudden -G
 

Jean Claude

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Yes, but without prior "zoom", the increasing of nose down and forward speed worry the pilot, before the low Rrpm becomes unrecoverable.
While during a bell-shaped trajectory, the pilot is still confident when the rpm is already unrecoverable.

It's also what Mike G's alarm would can anticipate.
 

fara

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Yes, but without prior "zoom", the increasing of nose down and forward speed worry the pilot, before the low Rrpm becomes unrecoverable.
While during a bell-shaped trajectory, the pilot is still confident when the rpm is already unrecoverable.

It's also what Mike G's alarm would can anticipate.

exactly. The very low and even zero G starts at what I would call the apex crown of the parabola meaning you could still be facing upwards while that happens and if you don’t understand that you will be ignorantly confident but it will cause a disaster. I absolutely think this is not what most pilots are taught. The conventional wisdom is the zero G only happens on the down side of a “pushover”. That’s not quite true. Well it’s not the whole truth. This thread and comments on it actually prove that very point. It’s not the fault of the pilots. This is really not covered in any flying handbook or anywhere else but it is what happens. In two blade semi-rigid rotor system aircraft it’s essential to understand this. It’s not so important in airplanes etc.

In the MGL EFIS which has the AHRS built-in and me paying attention to it flying in turbulence I saw transient low Gs that came and went without much effect on rotor RPM but these were very transient moments. It’s sustaining those low Gs that obviously causes the trouble.
 

Vance

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exactly. The very low and even zero G starts at what I would call the apex crown of the parabola meaning you could still be facing upwards while that happens and if you don’t understand that you will be ignorantly confident but it will cause a disaster. I absolutely think this is not what most pilots are taught. The conventional wisdom is the zero G only happens on the down side of a “pushover”. That’s not quite true. Well it’s not the whole truth. This thread and comments on it actually prove that very point. It’s not the fault of the pilots. This is really not covered in any flying handbook or anywhere else but it is what happens. In two blade semi-rigid rotor system aircraft it’s essential to understand this. It’s not so important in airplanes etc.
I don’t know any gyroplane flight instructors who teach that low Gs only happen at the top of a parabolic trajectory Abid.

There is a lot of information available on how a parabolic trajectory creates a low G event.

Some flight instructors keep it simple by teaching learners to avoid a zoom climb.

If a pilot wants to explore that regime of flying he should do some research first.

A flight instructor needs to emphasize the detail of things that are important and without a zoom climb or pilot induced oscillations; low g parabolic flight is unlikely in a gyroplane.

Part of the Robinson helicopter syllabus is extensive information on low G avoidance.

In my opinion with the more powerful engines not hanging on the propeller in a steep climb also becomes an important part of keeping the rotor loaded.
 

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fara

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I don’t know any gyroplane flight instructors who teach that low Gs only happen at the top of a parabolic trajectory Abid.

There is a lot of information available on how a parabolic trajectory creates a low G event.

Some flight instructors keep it simple by teaching learners to avoid a zoom climb.

If a pilot wants to explore that regime of flying he should do some research first.

A flight instructor needs to emphasize the detail of things that are important and without a zoom climb or pilot induced oscillations; low g parabolic flight is unlikely in a gyroplane.

Part of the Robinson helicopter syllabus is extensive information on low G avoidance.

In my opinion with the more powerful engines not hanging on the propeller in a steep climb also becomes an important part of keeping the rotor loaded.
Hi Vance:
Yes you are right. Robinson does have extensive info and advisories on avoidance on low G and its because they are using semi rigid 2 blade rotors like us. A lot of their advisories would be a good read for gyroplane pilots as well. Never push forward abruptly without reducing power. Never start descend without reducing power (PAT). At least these things should be emphasized by the gyroplane instructors.





Regarding the point of with powerful engines not hanging on prop, I have explored this carefully and with me being only 148 pounds, even with a 914 powered machine, I can see rotor RPM decrease when I go above 5500 engine RPM and pitched up fairly high and slow. 915 is even worse. Don't even go there. Definitely have to be careful about it.
 
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Jean Claude

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Above 0.7 g the Rrpm remains recoverable.
But less than 0.7g,Rrpm will not be recoverable if the duration is long enough.
However, a much lower g decreases the duration of the return to level flight.
Thus, surprisingly, the return to level flight decreases less the Rrpm with 0.4 g than with 0.6 g.
(In this simulations, 300 rpm is the limit unrecoverable)
Sans titre2.png
 
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Philbennett

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Hi Vance:
Yes you are right. Robinson does have extensive info and advisories on avoidance on low G and its because they are using semi rigid 2 blade rotors like us. A lot of their advisories would be a good read for gyroplane pilots as well. Never push forward abruptly without reducing power. Never start descend without reducing power (PAT). At least these things should be emphasized by the gyroplane instructors.





Regarding the point of with powerful engines not hanging on prop, I have explored this carefully and with me being only 148 pounds, even with a 914 powered machine, I can see rotor RPM decrease when I go above 5500 engine RPM and pitched up fairly high and slow. 915 is even worse. Don't even go there. Definitely have to be careful about it.

All good points and perhaps one of the pieces missing is not necessarily at the instructor level knowledge wise it is sometimes having the chance to pass on that information. Your recent accident gets emotive at some point because being blunt about potential issues in the circumstances causes obvious offence but it doesn't make it less valid. We waited some months and made a similar conclusion about the Lord Cavalon crash. The route to a safer future in the US is to have some regulatory protection/authority to stop a wilful owner/pilot from piloting a new machine too soon [and / or with little knowledge or experience] just because they can and with no real authority for those who might know better to stop them. Nice to debate with everyone over the years, take care and for those running the forum thank you for the efforts making something for others to engage with.
 

Vance

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The route to a safer future in the US is to have some regulatory protection/authority to stop a wilful owner/pilot from piloting a new machine too soon [and / or with little knowledge or experience] just because they can and with no real authority for those who might know better to stop them.
In my opinion Phil Bennett has made assertions about the effect of regulations in the USA that are unfounded.

I know an instructor who did not solo his client till they had over 100 hours of dual instruction.

I soloed one client at 90 hours of dual instruction.

I soloed at 54 hours of dual instruction.

I had a client Wednesday with 21 hours of dual and I was not able to solo them because they did not meet the standards despite that being our primary goal.

A flight instructor can withdraw a solo endorsement or further limit it if the instructor feels the learner is abusing their privilege.

The MINIMUM HOURS are the minimum hours; there is no number of hours that guarantee an approval.

The examiner makes sure the minimums have been met in the log book; gives the applicant the oral test and then the examiner flies with the applicant to see that they meet the flying portion of the practical test standards.

It takes as long as it takes.

With a sport pilot add on rating it takes two Certificated Flight Instructors to agree that the learner meets practical test standards.

With Sport Pilot Gyroplane as an initial rating it takes a CFI and a Designated Pilot Examiner to approve a Sport Pilot Gyroplane rating.

A CFI has absolute discretion about when to solo someone and absolute discretion about when to approve a learner for their practical test after the learner has the minimum amount of dual instruction.

Understanding the particulars of the low G parabolic path is not a part of the practical test standards.

If I am the examiner and the applicant can’t explain why a zoom climb is a bad idea to practical test standards they do not pass until they can.

Some people feel we need a required minimum number of hours for transition training.

To me it depends on the transition, the pilot and the situation.

I would not want more regulation adding expense to the transition to a different gyroplane.

It takes as long as it takes and I feel most pilots have judgement in the USA.
 
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Philbennett

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In my opinion Phil Bennett has made assertions about the effect of regulations in the USA that are unfounded.
Some people feel we need a required minimum number of hours for transition training.

To me it depends on the transition, the pilot and the situation.

I would not want more regulation adding expense to the transition to a different gyroplane.

It takes as long as it takes and I feel most pilots have judgement in the USA.
And this is where you are confused on the issues, overlook the obvious and refuse to acknowledge what is happening on a year to year basis.

I don't know if that is just stubbornness because you don't like the messenger, are just oblivious to what should be obvious or some other reason.

No doubt your attitude to training is as diligent as you say and good for you. Yet if you have a pilot who already holds a gyroplane pilot licence then he doesn't need to listen to you. He can tell you to poke your opinion and there is nothing you can do to put a halt to any madness that you as an FI might have a better idea of than the pilot shortly to have an accident.

Chris Lord killed himself and pax in a Cavalon with less than half a dozen hours on make/model. Fara had his customer crash on his first solo and not only did the that individual not want to do a fuller transitional phase to the model he didn't even elect to do what he did with a current FI. Aside from the conflict of commercial work it seems a lot of responsibility to shoulder with literally zero control.
 

Tyger

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Here's a good, recent video about teetering, turbulence, and airspeed in Robinsons (last part of a series on dissymmetry of lift):
 
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Vance

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And this is where you are confused on the issues, overlook the obvious and refuse to acknowledge what is happening on a year to year basis.

I don't know if that is just stubbornness because you don't like the messenger, are just oblivious to what should be obvious or some other reason.

No doubt your attitude to training is as diligent as you say and good for you. Yet if you have a pilot who already holds a gyroplane pilot licence then he doesn't need to listen to you. He can tell you to poke your opinion and there is nothing you can do to put a halt to any madness that you as an FI might have a better idea of than the pilot shortly to have an accident.

Chris Lord killed himself and pax in a Cavalon with less than half a dozen hours on make/model. Fara had his customer crash on his first solo and not only did the that individual not want to do a fuller transitional phase to the model he didn't even elect to do what he did with a current FI. Aside from the conflict of commercial work it seems a lot of responsibility to shoulder with literally zero control.
It appears to me from his post; Phil Bennett feels Chris Lord crashed because he didn’t have enough time in a Cavalon.

Does anyone else believe that?

Does anyone else believe that transition training would have helped Chris to address a control failure?

No one knows what happened in Utah and it appears to me Phil Bennett is basing his assessment on gossip.

Since I don’t know what happened in Utah I won’t pretend I know how to fix it.

The last thing I would want is more regulation based on Phil Bennett’s thought process.
 

Vance

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Here's a good, recent video about teetering, turbulence, and airspeed in Robinsons (last part of a series on dissymmetry of lift):
It is an informative video about helicopters.

In my opinion the information does not directly transfer to gyroplanes.

In my opinion retreating blade stall and or exceeding the maximum flapping angle does not limit the Vne of any gyroplane I have flown.

A helicopter rotor blade stalls from the tip inward creating control and rotor stability issues.

A gyroplane rotor blade stalls from the inside out making for a more benign event at higher indicated air speeds.

At speed a gyroplane rotor blade has a much lower angle of attack than a helicopter rotor blade at the same indicated air speed.

An airfoil stalls because the critical angle of attack has been exceeded.
 

Tyger

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Vance, if you were to look at the previous six videos in the series, you would see how he covers the things you mention.
 

Philbennett

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Does anyone else believe that transition training would have helped Chris to address a control failure?

Vance accidents are very rarely one dimensional. Chris Lords lack of familiarity of his aircraft is obviously a factor and transition training includes the A-check, the aircrafts limitations, including airspeed limitations, amongst many other things.

Regarding Utah, you may have heard of something called Occam's razor?

When the "gossip" comes from the people involved in the process to the point of the accident it surely becomes facts as we know them?

Can I ask btw what is this recent extension of the oddness with the reference to my full name? I am aware of my own name!!!
 

Vance

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Vance accidents are very rarely one dimensional. Chris Lords lack of familiarity of his aircraft is obviously a factor and transition training includes the A-check, the aircrafts limitations, including airspeed limitations, amongst many other things.

Regarding Utah, you may have heard of something called Occam's razor?

When the "gossip" comes from the people involved in the process to the point of the accident it surely becomes facts as we know them?

Can I ask btw what is this recent extension of the oddness with the reference to my full name? I am aware of my own name!!!
Does anyone beside Phil Bennett think that transition training would have helped Chris Lord deal with the control failure?

In my opinion there is nothing scientific about repeating gossip and building a hypothesis based on the gossip.

Phil Bennett appears to be using Occam's razor to distract from his reliance on gossip to form his theory about what happened in Utah.

He appears unconcerned that some of the gossip has been refuted on the Rotary Wing Forum or that Occam's Razor is about scientific investigation rather than unfounded speculation.

Definition of Occam's Razor by Merriam-Webster:
A scientific and philosophical rule that entities should not be multiplied unnecessarily which is interpreted as requiring that the simplest of competing theories be preferred to the more complex or that explanations of unknown phenomena be sough first in terms of known quantities.

 

Vance

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Vance, if you were to look at the previous six videos in the series, you would see how he covers the things you mention.
I agree Tyger; I have seen helicopters confused with gyroplanes too many times to not mention it as many will just watch the one video.
 
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