another look at the AutoGyro MTOsport crash of 11 September 2016 in Germany (D-MDOZ)

Tyger

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loftus;n1143928 said:
Personally if I were a betting man I'd guess that Magni blades would last longer than MTO blades, but I'm not sure what the upper limit on Magni blades has been shown to be. Nevertheless I'd be comfortable flying either. This is similar to the expiry date on medications - usually does not mean that that the medication will not work after the expiry date, but only that the manufacturer has tested the medications and can vouch for their efficacy for a certain period of time only.... I'd be interested to know if there are maximum blade times provided by other manufacturers, or can they guarantee their blades will last forever?

Magni state that their M-16 blades must be replaced after 2,500 hours.
 

Vance

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In my opinion the blade grips on the first rotor system were causing the stress riser that cracked the rotor blade at the hole so there was no reason to change the design of the blades.

In my opinion the strength of the AutoGyro blades with the new blade grips has proved to be satisfactory by more flight hours than any other brand of gyroplane.

In my opinion if the rotor hits the empennage in flight the gyroplane is in the process of crashing and the continued integrity of the rotor system is not going to change the outcome of the event.

In my opinion based on maintenance experience removing the blades more often than the recommended inspections for cracks is going to lead to more safety issues than simply following the factory recommendations for inspection. If field experience discovers a need for more frequent inspections I suspect the customers will be made aware of the change.

I have flown AutoGyro products enough to feel that flying more gently is not a viable option. I don't know how you would do that.

In my opinion the greatest stress on the blades is during taxi. Anything much below 200 rotor rpm is not going to help and there have been enough tip overs with the blades near flight rpm to suggest to me that it would be a very bad practice.

Because there have been no blade failures beyond the cracks on the first system and there has been a lot of tip overs; I feel this is a good example of the unreasonable fear of the blades integrity precipitating poor aviation decision making.

If I owned an AutoGyro product I would find the continued pursuit of the unreasonable fantasy about rotor system integrity being a safety issue disquieting

My loved ones who were less technically astute would probably worry about me.

Both of these things would reduce the joy I found in flying my gyroplane.

I see no value in fabricating a fantasy about the blades not being suitable and backing it up with unrelated pictures and baseless conjecture.

In my opinion there is no evidence that the blades on AutoGyro products are not airworthy and I often bet my life on that conviction.

My experience with AutoGyro products strongly suggests to me that they have mechanical engineers on staff.

Recently I talked to the wife of a client who is considering an American Ranger and to the best of my recollection she said to me: "I think these things are unsafe because they can’t even keep their blades attached." I asked her where she got the impression that gyroplanes didn't keep their blades attached and she told me the Rotary Wing Forum.

There is no telling how many other people are driven from gyroplanes by threads like this.

In my opinion gyroplanes have a poor safety record because of ignorance and stupid pilot tricks. It is not from any inherent design flaw.

Most people flying have someone who cares about them and giving them fuel for their anxiety hurts everyone connected with gyroplanes.

I emphasize the danger of flying to help people to develop a culture of risk mitigation.

It is probably safer to not fly.

I and all of my clients feel the reward justifies the risk.

The resolve of their loved ones is not so universal.
 

Kolibri

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In my opinion the blade grips on the first rotor system were causing the stress riser that cracked the rotor blade at the hole so there was no reason to change the design of the blades.
That's disputable. The RS1 are extruded, hollow at the root, and not impressively strong. The RS2 seems about the same.
In my opinion, AutoGyro does both the hub bar and blades poorly, and one cannot fix one without fixing the other.

Here's my forecast: AG will, within 3 years, dispense with RS2 and go to carbon fiber . . . without comment on the RS2.



I have flown AutoGyro products enough to feel that flying more gently is not a viable option. I don't know how you would do that.
Go for a test flight with an AG rep from Germany and ask if you can try out some of your airshow maneuvers. Or .
From what I heard directly from an experienced gyro CFI who attempted a steep turn, he was immediately and sternly cautioned.



In my opinion based on maintenance experience removing the blades more often than the recommended inspections for cracks is going to lead to more safety issues than simply following the factory recommendations for inspection.
Exactly how so, Vance?
For example, inspecting blades every 50 hours would only double the amount of lifetime disassembly/reassembly.
Isn't the RS2 up to that?

Or, conversely, based on your premise, why not inspect only every 200 hours and lessen the "
safety issues"?
Since you don't believe that RS2 will crack, why inspect so often as 100 hours?



In my opinion the greatest stress on the blades is during taxi. Anything much below 200 rotor rpm is not going to help and there have been enough tip overs with the blades near flight rpm to suggest to me that it would be a very bad practice.
I'd attribute many of those incidents to the nosewheel/rudder pedals linkage.
I've recent experience taxiing a gyro with a proper design of castering NW and differential toe brakes, and found it no issue taxiing with 100-150 rrpm.
And, 130-150 rrpm takes a noticeable weight off the system; no need for anything near 200.



In my opinion gyroplanes have a poor safety record because of ignorance and stupid pilot tricks. It is not from any inherent design flaw.
I agree with the former, but believe you belittle the latter (and almost always have, with nearly every gyro mfg. of discussion, including the crack-prone <2004 RAF hub bar).


My experience with AutoGyro products strongly suggests to me that they have mechanical engineers on staff.
You mean after their failed Rotor System 1 . . . or before?
Folks, remember that when RS1 first began to show cracking, AutoGyro reflexively blamed it on the owners for overly hard flying. I quote their April and September 2010 statements;

As the cause is not clear at this point (we assume it is caused by extreme maneuvers), a check of all rotor systems is necessary.
A problem has been found in service on an MTO series aircraft in the UK where, it is believed, high loads have been exerted on the rotor system as a result of manoeuvres considered to be outside handbook limits.
The elephant in that room is the long existence of an E-AB gyro rotor system which does not crack and fail even from repeated aerobatics, with 2000+ hour lifetimes.
So, in my opinion, posts like yours today are an example of what I call "defending osteoporosis as normal".

Furthermore, the Cranfield study proved that flying well within the limits of RS1's 6005 aluminum would still cause crack initiation and then rapid propagation.
Translation: it wasn't the pilots' fault.
But, did AutoGyro ever plainly admit that?



I see no value in fabricating a fantasy about the blades not being suitable and backing it up with unrelated pictures and baseless conjecture.
Ah, there you go again. Instead of dealing with my sequential points in the previous post, you resort to calling my clarion for caution a "fantasy".
What is fantasy in my view would be believing, without compelling evidence, that AutoGyro currently supplies a reliable 2500 hour rotor system on the heels of their RS1.




Recently I talked to the wife of a client [who] she said to me: "I think these things are unsafe because they can’t even keep their blades attached."
I asked her where she got the impression that gyroplanes didn't keep their blades attached and she told me the Rotary Wing Forum.
You could have pointed her to the two manufacturers which haven't that issue at all.

Aside from that, she no doubt read in that same thread opinions differing from mine. That's why it's called a forum.

Vance, you look out for the industry your way ("
See no evil."), and I'll look after it my way ("Most gyro mfg. don't really know what they're doing.").
The truth may be somewhere in the middle, and I trust the readers -- including relatives of gyro pilots -- to rationally weigh both sides and arrive at their own adult conclusions.

Regards,
Kolibri
 

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I'm not going to be convinced that Autogyro owners should be concerned that their rotor systems are inherently unsafe and likely to fail in flight. Pretty well stated overall by Vance. And yes threads such as this could be the beginning of completely unfounded rumors, with speculation (which by itself is fine) being taken as fact (which is not)
We've already heard that Magni recommend a 2500 hour limit on their blades.
It's a simple fact that manufacturers of certified aircraft, as are Magni and Autogyro, are under much more stringent requirements to publish component lifetime limits, service bulletins etc than are experimental only manufacturers. Whether or not Autogyro sell the same aircraft as experimental in the US or not is irrelavent.
So lets just hope that folks reading this thread are not going to come away with the idea that Autogyro rotor systems are inherently unsafe to fly, when standard aircraft service bulletins etc as provided by the manufacturer are followed.
 

Vance

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In my opinion based on your response Kolibri; you misunderstood every word I wrote.

You have given your opinion Kolibri and I have given mine.

In my opinion your responses are just more emotionally charged nonsense.

You are so far off track there is no point in responding to your "questions".

Just because you repeat something and no one bothers to refute it doesn't make it so.

I am going to explain to the other people on the Rotary Wing Forum what engineering is when I have some time. In my opinion the Kolibri concept of engineering is unrelated to reality.

I do not share your opinion of your sequential points.

My client was considering an American Ranger, not an AutoGyro product.

His wife chose to condemn all gyroplanes based on what she read here.

Like you Kolibri, she had a fear and went looking for a justification for that fear and a talking point. She found it in your many threads.

In my opinion neither American Ranger nor AutoGyro has a problem with their blades.

In my opinion nothing you have brought up refutes that opinion.
 

Kolibri

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loftus, I'm not challenging that AutoGyro gave a figure for rotor blade service life.
I'm skeptical of what figure they claimed.
2500 hours? Sounds more like marketing than engineering.



______________
Vance, you still need to justify this:

In my opinion based on maintenance experience removing the blades more often than the recommended inspections for cracks is going to lead to more safety issues than simply following the factory recommendations for inspection.
Exactly how is inspecting RS2 blades every 50 hours vs. every 100 hours "going to lead to more safety issues"?


His wife chose to condemn all gyroplanes based on what she read here.
And she was incorrect to do so.
She reminds me of the quip Mark Twain had about a cat, which having been burned by jumping on a hot stove, thereafter mistakenly avoided even cold stoves.



In my opinion neither American Ranger nor AutoGyro has a problem with their blades.
I didn't bring up or mention American Ranger. In neither of their two crashes to date did a rotor blade separate.

However, even the latest AutoGyro blade will often break off during taxi tip-overs.
Not always, but often enough to notice and show some curiosity.


I am going to explain to the other people on the Rotary Wing Forum what engineering is when I have some time.
Yes, you do that. And send AutoGyro the link. They need it more than any of us here.



______________
The BfU report on the D-MDOZ crash implied that rotor rpm decay and flap is what caused a blade to strike the tail.

However, nothing really suggests why that would have happened.
As my photos of the terrain show, the pilot had already reached a considerable altitude over the ridgeline just ahead, else he couldn't have been seen from town.
That tends to rule out a steep climb.

Also, the 513+ yds linear dispersal of parts and wreckage indicate that the gyro had considerable ground speed at time of its event.
There was no tailwind aloft to speak of (i.e., only 4-8 kts).
That tends to rule out too low airspeed.

Vance offered his opinion that the pilot's helmet detached earliest on, which directly or indirectly caused the rotor blade/tail strike.
I countered that this probably did not occur since the helmet was found near the gyro at the end of the debris trial and not at the beginning.
It seems to me more likely that the helmet came off while the stricken gyro was already falling.

Even assuming the detached blade was not already weakened at the outer bolt hole (which must be the premise of all AutoGyro defenders),
and assuming some cause for rotor flap, you're still left with that blade tearing first from the top down, and not first from the front to back (by hitting the tail).

The below picture plainly shows the tear progression.
Had the tail simply knocked off the blade, the doubler wouldn't be bent some 45° downward and thus breaking the front lower corner.


D-MDOZ torn rotor blade compared to original parts (copy).png

Either the blade broke first at the "hinge" of bolt hole and caused the rotor flap, OR . . . (yet unexplained) rotor flap broke the blade at the "hinge".
Neither should be acceptable, for either evinces an inherently weak design.

Study the right-hand photo of an uncrashed RS2 component and notice how little the doubler actually supports the blade.
Less than 50% of the blade surface area contacts the doubler.
There is plenty of room for blade flapping at the outer bolt hole within the doubler, something the new design was putatively supposed to prevent.


In not only my opinion, the RS2 blade is working at that point, which is little mystery why it continues to break there during even taxi tip-overs
despite the new and allegedly improved blade straps/hub bar of progressively thinner outboard sections to spread out the blade movement.

Unless Vance can somehow convince RS2 owners that 50 hour blade inspections are somehow "
going to lead to more safety issues",
they would be prudent to keep such a closer watch on those bolt holes than merely every 100 hours.

My clarion for caution could save lives if I am right. It seems surreal that some would express objections to that.

Regards,
Kolibri
 

Vance

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Kolibri;n1143968 said:
[COLOR]

______________
Vance, you still need to justify this:

Exactly how is inspecting RS2 blades every 50 hours vs. every 100 hours "going to lead to more safety issues"?


And she was incorrect to do so.
She reminds me of the quip Mark Twain had about a cat, which having been burned by jumping on a hot stove, thereafter mistakenly avoided even cold stoves.


I didn't bring up or mention American Ranger. In neither of their two crashes to date did a rotor blade separate.

Regards,
Kolibri

Most people on the Rotary Wing Forum have enough knowledge and experience to know why disassembling and assembling something for no reason has its hazards; for those who don't a brief explanation

When removing and replacing rotor blades I have often seen people reuse hardware, use torque wrenches that have not been calibrated for years and force things together in a destructive way. That is the reality of people working on their aircraft.

Like you Kolibri; my clients wife was looking for something to justify her fears with no knowledge or real interest in what she was reading. To her a gyorplane is a gyorplane and because someone says there is a problem with a gyroplane she embraces the words without understanding the concept.
 

Kolibri

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Most people on the Rotary Wing Forum have enough knowledge and experience to know why disassembling and assembling something for no reason has its hazards; for those who don't a brief explanation

When removing and replacing rotor blades I have often seen people reuse hardware, use torque wrenches that have not been calibrated for years and force things together in a destructive way. That is the reality of people working on their aircraft.
Well, if that's the case -- and because in your opinion the RS2 blades will not crack at the outer bolt hole -- then AutoGyro's 100 hour inspection would be excessive and thus unsafe.
Can't have it both ways . . .

Apparently I have more faith in the average AutoGyro owners to competently remove and replace their blades without committing the errors you describe.
If some of them find your characterization insulting, I wouldn't blame them.

_____
I'm not looking to "
justify" my "fears" of AutoGyro machines, because I will not fly in them (for multiple concerns).

Rather, I sincerely believe from the best evidence out there so far that their rotor blades will not reach anywhere close to 2500 hours, while eventually showing RS1-type cracks along the way.

Time may corroborate this, or entirely prove me wrong, but meanwhile blind faith in RS2 is not the way to bet given their RS1 history.
And without being able to read the rather coy "university study", blind faith is about all AG owners have right now.

Regards,
Kolibri
 

Alan_Cheatham

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Kolibri;n1143968 said:
The below picture plainly shows the tear progression.
Had the tail simply knocked off the blade, the doubler wouldn't be bent some 45° downward and thus breaking the front lower corner. [/COLOR]

Why do you draw the conclusion that the downward bend of the doubler was caused by the detachment of the blade and not after the blade detached when the main body of the aircraft struck the ground?

Why do you draw the conclusion that the blade separated in-flight and wasn't broken off as the wreckage crashed through the tree line?

Why do you draw the conclusion that the blade separated in-flight in its entirety and didn't loose a portion of its outboard section after striking the tail post?
 

Vance

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Some thoughts on the basics of Engineering.

In most organizational charts for small manufacturing companies Sales and Marketing are at the top because their projections drive the budget.

Design is next and is the interface between marketing and engineering. I was design.

Sales and marketing come up with a set of features they feel are marketable and design tries to create something with those features meeting price and reliability goals.

Design is a compromise and there are always ways to make the product what some might feel is better.

I did not insist on the engineers doing things the way I wanted if they could justify the change. There is always more than one way to meet the design goals.

I had 16 engineers answering to me and we had lots of meetings to discuss ideas for the details of new products and current products.

Engineering tests calculates and documents for manufacture.

Good engineering meets the goals for testing, production, cost, safety and lifespan.

Engineering change orders are very expensive and may be the result of poor engineering or a better idea.

If I were a designer at AutoGyro I would be happy with a rotor system design that lasted twelve years with minimal maintenance and no safety issues. In my opinion AutoGyro has achieved that.

Several parts of the rotor system are not how I would have done them and yet they meet the goals of safety, cost, manufacturability, weight, maintenance and life span.

They could go to fabricated aluminum blades and in my estimation would have to add $15,000 to the selling price of each gyroplane for no benefit that I can see.

That would be a hard sell to marketing who wants to remain price competitive.
 

Kolibri

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Good engineering meets the goals for testing, production, cost, safety and lifespan.

Several parts of the rotor system are not how I would have done them and yet they meet the goals of safety, cost, manufacturability, weight, maintenance and life span.
Safety is being disputed in this thread, and lifespan of 2500 hours has nowhere been actually demonstrated to my knowledge.

In my opinion, a low cost seems to have prevailed against all other considerations.

The entire blade is extruded (cost is probably <$300 per blade).
I expect that the doubler is also extruded.
Steel blades straps were dispensed with, as the 6005 aluminum "hub bar" acts as the blade straps.

I cannot imagine how to more cheaply produce a rotor system than RS2 . . . unless it was RS1.



They could go to fabricated aluminum blades and in my estimation would have to add $15,000 to the selling price of each gyroplane . . .
I've no idea where you concocted such a figure.
AutoGyro's RS2 system sells for about $4,800. For only $1,200 more, one could enjoy the incomparable Sport Rotors.
Many owners of AutoGyros, ELAs, and Xenons have upgraded (just stating a fact; not hawking blades here).


for no benefit that I can see.
Wow. Really? It is of "no benefit" to enjoy rotor blades which will not crack during a 3000+ hour service, and not break off during impacts?
Not to mention higher cruise speeds?
Or not having Kolibri harangue cheap extruded blades? :wave:


___________
Hi Alan, thanks for the good and relevant questions:


Why do you draw the conclusion that the downward bend of the doubler was caused by the detachment of the blade
and not after the blade detached when the main body of the aircraft struck the ground?
Because the remaining blade root in the rotor assembly seemed to impact the ground about parallel.
The still detached blade shows little damage from impact.
Also, the forest soil wouldn't seem to lend itself to breaking and bending the doubler's bottom edge.

Finally, I seem to recall other broken RS2 blades with similar breaking/bending of their doubler.


fetch?id=1143798&d=1555599974.png


Why do you draw the conclusion that the blade separated in-flight and wasn't broken off as the wreckage crashed through the tree line?
Because the detached blade was not found near the gyro or through the treeline crash trajectory.
In fact, despite intensive search, the detached blade was never found at all.
This suggests that the breakage occurred early on, and with powerful rotational energy.
I suspect it was vigorously flung farther than the searchers imagined, outside the search radius. They'd have most likely found it, otherwise.



Why do you draw the conclusion that the blade separated in-flight in its entirety and didn't loose a portion of its outboard section after striking the tail post?
Theoretically possible, but I think unlikely.

Such would have then required the inner piece to later tear off the hub bar, thus doubling the odds that searchers would have found at least one piece of the two.
But they found no piece at all. I don't doubt their meticulousness, given that there were over 100 of them and very small items were found (book pages, helmet ear piece, etc.)

Finally, the history of where the RS2 blade breaks shows the root as the prime area (and almost the only area).
When they break, it's almost never at the outer end, although they do often fold somewhere in the middle.

Regards,
Kolibri
 

Kolibri

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Less than 50% of the blade surface area contacts the doubler.
There is plenty of room for blade flapping at the outer bolt hole within the doubler, something the new design was putatively supposed to prevent.
AutoGyro Rotor System 1 blade cracking.png
 

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Alan_Cheatham

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Kolibri;n1143975 said:
Because the detached blade was not found near the gyro or through the treeline crash trajectory.
In fact, despite intensive search, the detached blade was never found at all.
This suggests that the breakage occurred early on, and with powerful rotational energy.
I suspect it was vigorously flung farther than the searchers imagined, outside the search radius. They'd have most likely found it, otherwise.

The bend damage to the blade doubler would suggest the blade was broken off by an applied bending load, something you could get if the aircraft was descending through a tree line.
The fact that the searchers never found the blade could suggest the blade is lodged in a tree top rather than it being flung some great distance outside the search area.

If the blade failure was from a fatigue fracture one would expect to see a clean separation of the blade and no bending of the doublers given the enormous tensile forces pulling outward on the blade.
 

Philbennett

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Kolbri Please dont reply with a 1000word unsubstantiated opinion give the facts.

i am not a rotor engineer and neither are you. We have all heard your theory on autogyro blades so could you please post links to the FAA rotor blade regulation and the vast documentation that clear you think exists with their competitors.

Otherwise im bored with the empty claim.
 

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so could you please post links to the FAA rotor blade regulation and the vast documentation that clear[ly] you think exists with their competitors
Sorry, Phil, but I could not glean exactly what you meant by that.


____________
The bend damage to the blade doubler would suggest the blade was broken off by an applied bending load,
Yes, Alan, I agree.

. . . something you could get if the aircraft was descending through a tree line.
Uh, well, if the gyro were descending through the trees . . . upside down.

But if the blade was still attached upon reaching the trees, then what made the gyro descend catastrophically at all?
No, I think it still makes more sense that the blade hit the tail at altitude, and was torn off at altitude.


The fact that the searchers never found the blade could suggest the blade is lodged in a tree top rather than it being flung some great distance outside the search area.
Yes, it could suggest that.

If the blade failure was from a fatigue fracture one would expect to see a clean separation of the blade
and no bending of the doublers given the enormous tensile forces pulling outward on the blade
It doesn't look that way to me.
Rather, it strongly indicates stress from rapid coning and flattening forces, not solely from centrifugal forces.

The tear is at an angle from top to bottom: from the center topside of the last bolt hole towards the bottom of the blade.
The stress riser was exactly in the same place as the RS1 blade cracks:


AutoGyro Rotor System 1 blade cracking.png
 

Vance

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Kolibri;n1143982 said:






Is anyone going to claim that there is zero fretting of the doubler ribs on the leading edge of the blade? Or on the contact surfaces in the center?
On this point, AG owners are welcome to post photos of their blade inspections. I suspect that as 300+ hours are accumulated, the fretting will be obvious to see.

The 6 retention bolts are drilled straight through the large center blade hole.
Where else but the outer bolt hole can the racing of molecules focus?
The blade is bending there, and apparently more there than at the lateral end of the doubler.
An internal "hinge" is being created in the blade itself. It will just take longer in the RS2 vs. RS1.

Please carefully inspect your AutoGyro blades. I'd use a jeweler's loupe with a bright flashlight.

Safe flying,
Kolibri




26 APRIL 2019 REPLY TO THE BELOW ____________


Sorry, Phil, but I could not glean exactly what you meant by that.


____________

Yes, Alan, I agree.


Uh, well, if the gyro were descending through the trees . . . upside down.

But if the blade was still attached upon reaching the trees, then what made the gyro descend catastrophically at all?
No, I think it still makes more sense that the blade hit the tail at altitude, and was torn off at altitude.



Yes, it could suggest that.


It doesn't look that way to me.
Rather, it strongly indicates stress from rapid coning and flattening forces, not solely from centrifugal forces.





The tear is at an angle from top to bottom: from the center topside of the last bolt hole towards the bottom of the blade.
The stress riser was exactly in the same place as the RS1 blade cracks:

I feel it is safe to say the nose on the spacer is there to make assembly easier and is not a load path to anything. They may feel it looks more finished than the way Sport Rotors uses separate spacers. Having assembled both there is no question the AutoGyro system is easier to assemble.

I have run out of new ways write that there are a lot of AutoGyro rotor systems flying a lot of hours without trouble.

If there were an actual design flaw we would have heard about it by now.

In my opinion if you follow the factory recommendation for inspection things will be fine. I don't know if the inspection interval has changed since we last serviced the Cavalon.

I don't know how long the rotor system will last and AutoGyro GMBH wants to be sure their calculations and testing is valid so they mandate the inspections for cracks because the rotors are a flight critical component.

I feel it is important to replace the hardware and use a recently calibrated torque wrench when you take the system apart for inspection and put it back together. The fasteners should slide into place without force. If they don't slide into place it is an alignment issue that should not be solved with even a soft face mallet or a tapered drift. I have seen people using both.

I feel this drivel misdirects the focus from the appropriate preflight inspections and condition inspections.

In my opinion it is fear mongering based on ignorance.
 

Kolibri

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1000+
I have run out of new ways write that there are a lot of AutoGyro rotor systems flying a lot of hours without trouble.
Vance, don't sell yourself short. You seem to always rise to the occasion when defending AutoGyro.


If there were an actual design flaw we would have heard about it by now.
Not if it's taking several hundred hours for the blade to flex fatigue at that point.

The average fleet hours on RS2 equipped AutoGyros is probably under 500 hours/machine.
If the RS2 is an improvement over the RS1 (and I concede that it probably is), then a continuing stress crack at the bolt hole will take more flight hours to manifest.

D-MDOZ had only 333 hours, but a very high number of landings -- 1073.
That's a landing on average every 18 minutes 37 seconds.

The gyro was flown (with another MTOsport, D-MDGO) for commercial flight-seeing, which in German is called a Rundflug (round-trip flight).
The round-trip through the scenic valley near Freiburg was about 12 miles, comporting well with the 18.6 minute Hobbs/landing average.

If my fatigue failure hypothesis is correct, then the higher landing cycle probably heavily contributed to a lower hour figure of breakage than what would be common.

There was nothing in the BfU report, and nothing in this thread, to strongly indicate rotor rpm decay and rotor flap.
Not the weather, not the flight path, and not the pilot.

Until I've compelling information otherwise, I'll stick with the theory of fatigue failure.
Considering the RS1 history, Occam's Razor is relevant here.


_________
If a former Cavalon owner (or beneficiary) wants to dismiss all this as "
drivel", well, that's his prerogative.
But to claim that my thread "
misdirects the focus from the appropriate preflight inspections and condition inspections" is so without merit as to be ridiculous.

I've urged AutoGyro owners to pay more attention to their gyros, not less.

Regards,
Kolibri
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,582
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
You response indicates to me you didn't understand anything I posted Kolibri.

I can't help you Kolibri; you are lost in an alternate reality of your own construction.

There are lots of people with lots of hours.

I put four hundred hours on a Cavalon in a year.

There were lots of hard landings and lots of aggressive flying along with some off airport operations.

The last time I trained at Spanish Fork; I put 30 hours on in five days with about two hundred landings. Weather kept me from flying more.

I flew seven and a half hours in one day.

The rotor system is well tested.

It is not unusual to put on over six hundred hours doing flight training with lots of hard landings in a year.

Some of the flight schools are flying off rough fields.

There is a lot to be more concerned about when flying a gyroplane than the Auto Gyro rotor system.

Follow the recommendations for inspection and carry out the prescribed maintenance and you will have a positive consumer experience as demonstrated by the high resale value of AutoGyro products.
 

Kolibri

FW and Gyros
Joined
Oct 17, 2014
Messages
1,636
Location
Wyoming
Aircraft
Cessna 152, 172, 172RG, 177, 206 -- Piper 180 -- RV-7A -- Calidus -- RAF2000 -- Sport Copter II and
Total Flight Time
1000+
Your Cavalon's operational tempo for its first 400 hours proves but one thing: a new broom sweeps cleanly.
You'd have worn out the machine in another year or two, probably beginning with the rotor blades.
AutoGyros are lightweight and not robust. That's acceptable for most owners.
(I'd caution one on the purchase of a used AutoGyro with over 300 hours.)
A retiree could buy a new machine, put 50 gentle hours/year for a decade and have a marvelous and safe time.

But imagine that one could fly it hard for 1000+ hours with no issues is optimistic at best.

__________
RS1 did not develop cracks until several hundred hours; and some didn't crack at all even past 700hours.
Since RS2 is a likely improvement, if fatigue failure is still an issue, it will take longer to manifest.

Rough field work, and/or higher landing cycles, will accelerate any material fatigue issue.


The rotor system is well tested.
Not to anywhere near 2500 hours. And probably not even 1500.

AutoGyro owners are the test pilots, just like they were for Rotor System 1.

Vance, where were all their mechanical engineers for RS1? Hmmmm?
 

Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,582
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
Field experience always has value.

It doesn't take much experience with airworthiness directives to understand field experience is a part of the engineering process in aviation.

It appears to me that the engineers at AutoGyro did not correctly anticipate the loads from the customer use for rotor system one and field experience motivated a redesign of the blade grips.

As far as I know no one was hurt using the first rotor system.

You live in a fantasy world if you imagine that everything is engineered correctly when it leaves the factory in any industry.

At one time I had an engineering job shop in the San Carlos, California and made my living correcting engineering miscalculations from many high tech manufactures.

Engineers make an educated guess and fix it if it doesn't work out.
 
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