First jump takeoff in France

[anthom]

But that clearly is a statistical question, Vance. If you have a flaw in your design it is much more likely to show up if you sell 3000 aircraft instead of, let's say, 30. Or, in the same context, if Boeing had sold just three 737MAX aircraft these would probably still be flying.

Quote: AutoGyro had not made that many gyroplanes when the problem was discovered. /Quote
What time are we talking here, ten years ago or fifteen?

Perhaps you might want to try and get over the fact that currently the world wide market leader in autogyros is a German company...;-)

What does being a German company have to do with the issue? Or being the biggest in sales. It is also my understanding that the Company has since filed for "Preliminary Insolvency". It does not dispel the fact that there were failures, irrespective of your statistics. Statistics aside, what if the designs were flawed during the early evolution of the product, and hence caused the failures?

Suppose the evolution started with a flawed design and the initial 300 of the 3000 machines were flawed, does that mean that the flaws occurred because of the large numbers produced, or the fact that the initial designs were not proper? So statistically, if they had stopped production after 300, the flaws would have still manifested and shown up.

 

[Tyger]

It seems to me that manufacturing errors may become more evident with larger numbers, because only a certain percentage will have a problem, whereas design flaws will be present in every example produced. Then it's more a matter of time for the flaws to be discovered, as opposed to total numbers existing.

 

[kolibri282]

Quote: Then it's more a matter of time for the flaws to be discovered, as opposed to total numbers existing. /Quote
But here again the number of aircraft of a brand is important. The use of aircraft probably follows a standard distribution. Most aircraft will fly a certain number of hours per year some much less some much more. A problem that is fatigue related will first materialize in those aircraft with more operating hours. The higher the number of aircraft sold the higher the number of those with lots of operating hours, hence the more likely it is that flaws are found. Also if a problem crops up in a small batch of aircraft this will quite likely rather be classified as a "Monday Machine".

As for "Preliminary Insolvency" I understand this is a purely legal step to cope with the sharp decline in the market mainly in the US and China due to COVID. German media say that production continues unabated.

 

[anthom]

Hey Kolibri282, I know enough to not get into an argument with you that never ends. The reason that I mentioned the issue of "primary insolvency" was because of the fact that I felt you were condescending in your statement to Vance, "Perhaps you might want to try and get over the fact that currently the world wide market leader in autogyros is a German company...;-)", which is completely irrelevant to the issue at hand in light of the issues that he brought out. Perhaps you are missing the point. But again, I see no point in arguing over this with you. Just stick to the facts, and we can all get along just fine.

 

[kolibri282]

Quote: I felt you were condescending in your statement to Vance /Quote
That was definitely not my intention.

My impression was, that Vance wanted to tease me a bit by mentioning problems of a German manufacturer (certainly over the years many manufacturers around the globe had to tackle some problem), so in return I pulled his leg a bit about sales numbers, please note the smiley at the end of the sentence.

If Vance would feel my remark was condescending I will not hesitate to apologize to him.

Quote: which is completely irrelevant to the issue at hand in light of the issues that he brought out. /Quote
Not quite, as I tried to explain many types of problems will crop up more often when the number of aircraft of a certain type is large, so I pointed out that the company with the largest market share is also the one with the highest probability of issues developing.

 

[loftus]

While we are on the subject of the Auto Gyro blade failures, were there any failures in flight or were these all or mostly cracks picked up on inspection?

 

[rwdreams]

While this was a sikorsky tail rotary hub. Huey's are often available. How would you go about determining if those hub bearings are appropriate for a jump application? Just wondering, different gripes and hub components would have to fabricated.

 

[skyguynca]

While this was a sikorsky tail rotary hub. Huey's are often available. How would you go about determining if those hub bearings are appropriate for a jump application? Just wondering, different gripes and hub components would have to fabricated.

It is not really if the bearing in the grips are suitable, is the assembly is strong enough. These grips can not be just removed from the head assy and attached to a big block of aluminum as he did with the Sikorsky tail rotor grips. While the bearings maybe just fine and can handle the dynamic and static loads, the grips themselves may not handle the centripetal load of a set of 22 or 25 ft rotors.

I worked on Huey's for years and I can say those tail rotor blades are extremely light, even at the high rpms they run I seriously doubt it will come close to the loads applied by a set of 7in chord and 12 ft long rotor blade. Also the blade grips themselves are pretty narrow, it would be difficult to mount the blades.

There are a lot of other helicopter tail rotor assy that have flapping hinges that support bigger blade assy. The grips he is using are from Sikorsky tail rotor that have flap hinges. That is why the block of the head is machined to fit very precisely square to the base of the grip to hold these grips by the flap hinges and keep them stable and locked in place so the head can teeter to handle blade flap.

You can see in post 1 pic the very close tolerance and also a bolt used for fine adjustment of the coning angle
In post 2 pic you can see both the top and bottom bolts used to adjust the coning angle and the teeter bearing in the center block.

 

[Abid]

While we are on the subject of the Auto Gyro blade failures, were there any failures in flight or were these all or mostly cracks picked up on inspection?

I believe they were picked up on inspection in the UK in 2010. The problem was the design as AutoGyro copied AirCopter rotor system. Also the Trendak and Xenon variances that had issue were also based on Aircopter rotors I believe (someone please correct me if I am wrong). Seems like Aircopter design had a flaw on the clamping section of hub bar to the blade and all these are leftovers of that. Also the use of 8 mm bolts with higher torque versus 10 mm which spreads the clamping force may be a contributing factor but I do not know enough to say that definitely.

I do believe they reduced the life of those rotor systems to 700 hours and mandated a change to rotor system 2 to take care of the problem in the fleet if I recall right. This has been discussed before and seems to point to AirCopter design legacy in the hub bar/blade clamping area

https://publicapps.caa.co.uk/docs/33/20110712MPD2011006E.pdf

 

[Smack]

It is not really if the bearing in the grips are suitable, is the assembly is strong enough. These grips can not be just removed from the head assy and attached to a big block of aluminum as he did with the Sikorsky tail rotor grips. While the bearings maybe just fine and can handle the dynamic and static loads, the grips themselves may not handle the centripetal load of a set of 22 or 25 ft rotors.

I worked on Huey's for years and I can say those tail rotor blades are extremely light, even at the high rpms they run I seriously doubt it will come close to the loads applied by a set of 7in chord and 12 ft long rotor blade. Also the blade grips themselves are pretty narrow, it would be difficult to mount the blades.

There are a lot of other helicopter tail rotor assy that have flapping hinges that support bigger blade assy. The grips he is using are from Sikorsky tail rotor that have flap hinges. That is why the block of the head is machined to fit very precisely square to the base of the grip to hold these grips by the flap hinges and keep them stable and locked in place so the head can teeter to handle blade flap.

You can see in post 1 pic the very close tolerance and also a bolt used for fine adjustment of the coning angle
In post 2 pic you can see both the top and bottom bolts used to adjust the coning angle and the teeter bearing in the center block.

I'm not 100% sure about that bolt 'setting the coning angle'.
When I zoom in on the picture, the bolt is very close to the edge of the center block (teeter).
That bolt on top (picture 2) has a washer; that washer looks like it is overlapping the grip.
If there is another washer on the bottom, I'm thinking that rather than 'setting' the coning angle, that bolt/washer (nut, too?) are actually just clamping the grip and preventing it from flapping independent of the center block (teeter).
I don't see the 'fine adjustment'.
For the mechanism to work, the grips must not move; all they can do is rotate along their long axis to change blade pitch.
I agree that setting the grips angle to the teeter would make a built-in coning angle, but I'm missing how you think that works.

As it appears to be 'locked down', there is no point to a flapping hinge there, only the thrust bearings that allow pitch change.
Brian

 

[loftus]

I believe they were picked up on inspection in the UK in 2010. The problem was the design as AutoGyro copied AirCopter rotor system. Also the Trendak and Xenon variances that had issue were also based on Aircopter rotors I believe (someone please correct me if I am wrong). Seems like Aircopter design had a flaw on the clamping section of hub bar to the blade and all these are leftovers of that. Also the use of 8 mm bolts with higher torque versus 10 mm which spreads the clamping force may be a contributing factor but I do not know enough to say that definitely.

I do believe they reduced the life of those rotor systems to 700 hours and mandated a change to rotor system 2 to take care of the problem in the fleet if I recall right. This has been discussed before and seems to point to AirCopter design legacy in the hub bar/blade clamping area

https://publicapps.caa.co.uk/docs/33/20110712MPD2011006E.pdf

Yes thanks; just trying to establish if there were any in-flight failures like with the Titanium.

 

[Abid]

Yes thanks; just trying to establish if there were any in-flight failures like with the Titanium.

No I think they caught them before anything like that happened.

 

[rwdreams]

So that I'm am clear on the choice of the design. A larger tail rotor will tolerate the stress of a light rotor. But will usually have a flapping hinge. Which must be disabled in a teetering rotor. Does anyone recall an application utilizing a larger prop hub. It would not have a flapping hinge. But may not tolerate the stress. Thank you in advance.

 

[Grodou]

Michel's latest test...
Looking more and more controled.
(Immediate landing is voluntary.)

 

[Vance]

Looks like progress to me. Good job!

 

[wolfy]

Well done Michel.

wolfy

 

[Eric S]

Michel's latest test...
Looking more and more controled.
(Immediate landing is voluntary.)

Things sure do happen fast. I would love to watch that jump in high resolution and slow motion. Is his left hand manually dropping the collective soon after lift off?

His right hand is busy on the cyclic, but it appears he has good control.

 

[Tyger]

I don't believe he has a collective, per se. As I understand it, the spinup is at zero pitch, and the change to normal pitch required for the jump and subsequent flight comes from pressing a button on the cyclic.

 

[Martin W.]

Things sure do happen fast. I would love to watch that jump in high resolution and slow motion. Is his left hand manually dropping the collective soon after lift off?

His right hand is busy on the cyclic, but it appears he has good control.

No collective . Flat pitch held via an electric solenoid during prerotation . Button released , goes to full pitch , takeoff , then flyweights reduce pitch to gyro mode once rpm diminishes to normal. Other than a few stabs of the cyclic it looks like a smooth takeoff. Remember this is a new concept so probably even smoother takeoffs will come with more experience.

 

[Tyger]

What exactly is a "flyweight"? I am not familiar with the term.