Safest side by side Gyro in the world? M24 vs Cavalon

[Mike G]

Proportion of all machines involved in fatals.

AutoGyro 1.3% [1 in 77]
Magni .....2.3% [1 in 43]
ELA ....... 4.4% [1 in 23]

[based on my last update over a year ago. I don't expect it to have changed much. Maybe by a decimal.]

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Rod can you explain your percentages please. Example 1 in 77, what does the 77 represent?
Mike

 

[TyroGyro]

Rod can you explain your percentages please. Example 1 in 77, what does the 77 represent?
Mike

It's simply the inverse of the percentage. [for example, 33% = 1 in 3]

1 in 77 machines = 1/77 = 1.3% OR 1/1.3% = 77

In other words, on average, for every 77 machines produced, one has ended in a fatality.

Put another way, with average "luck", your odds of dying in such a machine are 76/1 against. [of course, this is simplistic, and many factors will determine your personal actual odds: training, skill, location, experience, recency, maintenance, ADM, bad luck, etc.]

 

[Mike G]

Abid, you are absolutely right. If we analyze the causes of fatal accidents, the human factor is the overwhelming cause of most of them. Most modern serial gyroscopes are built with enough care for the pilot. Unfortunately, if a human fails, we have to rely on the design of the gyro to protect us at least a little.

If the human fails but he has a GWS he has a good chance of not needing a better designed cockpit, although I agree it is a plus.
I made the point when you posted these design advantages (which I applaud) before, I'm all for better more protective cockpits etc, but surely it's better not to have an accident in the first place. That is what the GWS does for you.
Mike

 

[Abid]

In many Xenon derived crashes including DULV certification ones the mast breaks off because it is too stiff and weakest link is the joint. That alone negates most of everything else. A rotating rotor in an accident allowed to break off on impact will go anywhere it pleases to go in a completely uncontrolled fashion. If you want to claim Argon to be superior structure, fix that. It is an engineering problem and most other masts bend but not break off completely usually. Mast breaking off should be a rare exception. In an accident where the aircraft is falling out of the sky the cockpit's strength is immaterial. It is only relevant in crashes which are survivable to begin with, which are on or near the ground crashes.
Cavalon is also Monocogue structure. These structures are neither better nor worse than framed structures. They are designed to simply behave a certain way. In monocoque structures, field repairs for most of the market are going to be more tricky because you need a proper composite shop and a detailed layup and chemical data to repair properly.
The main “roll cage” in gyroplanes and trikes both comes from the mast and landing gear. They aren't powered parachutes (PPC) which do not have a tall mast and have a flexible wing so they need a real roll cage. Xenon was originally a stolen enclosed type PPC carriage design by Celier and that is what and where it comes from. Gyroplanes don’t need another roll cage unless your mast breaks off clear which yours and Tercels do and the Polish CAA in their infinite wisdom made you guys make the mast structure even more stiff which is in fact incorrect both for vibration propagation and fatigue into other elements of the structure like engine mounting and cabin hop and also for allowing the mast to bend when it takes a shock load hit in a dynamic rollover. In such an accident you want all these elements to bend and absorb the energy and dissipate it but not have a runaway rotating blade sub-assembly going whichever way it chooses. The main thing for the pilot to do is to keep their body parts inside the gyroplane with proper restriction from seatbelts so in the crash these parts can do their job to dissipate the energy. The only advantage I see in Argon or Xenon is the extra wide wheel base. It certainly will resist rollover more than others. That makes sense.

 

[Greg Vos]

In many Xenon derived crashes including DULV certification ones the mast breaks off because it is too stiff and weakest link is the joint. That alone negates most of everything else. A rotating rotor in an accident allowed to break off on impact will go anywhere it pleases to go in a completely uncontrolled fashion. If you want to claim Argon to be superior structure, fix that. It is an engineering problem and most other masts bend but not break off completely usually. Mast breaking off should be a rare exception. In an accident where the aircraft is falling out of the sky the cockpit's strength is immaterial. It is only relevant in crashes which are survivable to begin with, which are on or near the ground crashes.
Cavalon is also Monocogue structure. These structures are neither better nor worse than framed structures. They are designed to simply behave a certain way. In monocoque structures, field repairs for most of the market are going to be more tricky because you need a proper composite shop and a detailed layup and chemical data to repair properly.
The main “roll cage” in gyroplanes and trikes both comes from the mast and landing gear. They aren't powered parachutes (PPC) which do not have a tall mast and have a flexible wing so they need a real roll cage. Xenon was originally a stolen enclosed type PPC carriage design by Celier and that is what and where it comes from. Gyroplanes don’t need another roll cage unless your mast breaks off clear which yours and Tercels do and the Polish CAA in their infinite wisdom made you guys make the mast structure even more stiff which is in fact incorrect both for vibration propagation and fatigue into other elements of the structure like engine mounting and cabin hop and also for allowing the mast to bend when it takes a shock load hit in a dynamic rollover. In such an accident you want all these elements to bend and absorb the energy and dissipate it but not have a runaway rotating blade sub-assembly going whichever way it chooses. The main thing for the pilot to do is to keep their body parts inside the gyroplane with proper restriction from seatbelts so in the crash these parts can do their job to dissipate the energy. The only advantage I see in Argon or Xenon is the extra wide wheel base. It certainly will resist rollover more than others. That makes sense.

You make some very good points, IIRC Cillier is on record about 13 years ago chanting the breakaway mast during a crash was in fact his brainchild and contribution to safety …of course we know his credibility.

 

[IgnacioParodi]

Which companies or Gyros that are still in production today, have had structural failures from factory????????????

 

[Abid]

You make some very good points, IIRC Cillier is on record about 13 years ago chanting the breakaway mast during a crash was in fact his brainchild and contribution to safety …of course we know his credibility.

Hmmm. Really . Interesting. Celier is not an engineer as far as I know and I doubt he could on purpose actually design something like that except by a lot of trial and error. I doubt his claim and I think he is wrong to claim that a breakaway mast is a positive feature.
Usually these things are never really single-handedly designed completely and they also have to deal with compliance or testing. I know the Polish CAA made them stiffen up the mast because they themselves don’t understand.

 

[Abid]

Which companies or Gyros that are still in production today, have had structural failures from factory????????????

The largest one. AutoGyro. You saw the gimbal block tore itself apart in the UK accident and also seems like in Beverly, Mass accident.
They have had cracks in the rotor blades at one point because of incorrectly designed hub bar interface to hold the blades. In their new rotors again there have been cracks found in the UK I think (please correct if I am wrong).
AG has also has mast cracking around the weld where engine mounts. I have fixed a couple. I have seen that in Europe also.
They have had several prerotator brackets crack but they are not a flight risk.
They have had a few HTC prop blades delaminate including in the air in Texas and one suspected in Arizona. HTC props are made by AG themselves.

ELA has had tail booms break off at the butt welds causing fatal accidents in France and Spain. Not the Eclipse series though.
Seen cracks on two sets of ELA composite blades here in Florida. They were caught before they caused any issues in flight and changed.

Artur Trendak had rotor blade come apart in a Polish gyroplane accident killing my friend and former trike world champion and I believe also gyroplane European champ. They released an AD.

In an accident in Florida Tango gyroplanes Russian one rotor blade was seen coming off the gyro 400 feet away from where the gyro ended up.

TAG Australia gyro had carbon fiber blades whose tip weight inserts were not properly structurally glued in the blades so they slid all the way out in flight breaking the thin tip caps. That caused such horrendous vibrations that it caused the masts to break off. That would be expected with such vibrations. At first they thought it was the folding mast which I knew it couldn’t be. Then someone figured it out. That issue however has been fixed since then.
Added: I forgot someone did also post picture of a crashed TAG frame and complained that the welding on Titanium was bad because the break in mast to keel junction and another area was right in the middle of the TIG weld bead. That does sound correct to me. A proper penetration TIG weld should not break in the weld bead but right next to it due to shock load and impact. This was on one of the TAG gyroplanes that lost tip weight in the blade which caused the accident. So the weld breaking was not the cause of the accident just showed the improper low penetration of the weld.

I can’t think any other true structural failures in any current batch of production gyroplanes.

 

[RogerB]

The largest one. AutoGyro. You saw the gimbal block tore itself apart in the UK accident and also seems like in Beverly, Mass accident.
They have had cracks in the rotor blades at one point because of incorrectly designed hub bar interface to hold the blades. In their new rotors again there have been cracks found in the UK I think (please correct if I am wrong).
AG has also has mast cracking around the weld where engine mounts. I have fixed a couple. I have seen that in Europe also.
They have had several prerotator brackets crack but they are not a flight risk.
They have had a few HTC prop blades delaminate including in the air in Texas and one suspected in Arizona. HTC props are made by AG themselves.

ELA has had tail booms break off at the butt welds causing fatal accidents in France and Spain. Not the Eclipse series though.
Seen cracks on two sets of ELA composite blades here in Florida. They were caught before they caused any issues in flight and changed.

Artur Trendak had rotor blade come apart in a Polish gyroplane accident killing my friend and former trike world champion and I believe also gyroplane European champ. They released an AD.

In an accident in Florida Tango gyroplanes Russian rotor blade were seen coming off the gyro 400 feet away from where the gyro ended up.

TAG Australia gyro had carbon fiber blades whose tip weight inserts were not properly structurally glued in the blades so they slid all the way out in flight breaking the thin tip caps. That caused such horrendous vibrations that it caused the masts to break off. That would be expected with such vibrations. At first they thought it was the folding mast which I knew it couldn’t be. Then someone figured it out. That issue however has been fixed since then.

I can’t think any other true structural failures in any current batch of production gyroplanes.

No mention of Magni?

 

[WaspAir]

It's a pretty long, scary list.

 

[Abid]

No mention of Magni?

Or AR-1
I don’t know of serious structural failures in them causing direct flight risk. There have been fatal accidents but not due to structural failures.

 

[Abid]

It's a pretty long, scary list.

It also tells you being certified (primary category cert with FAA and Cavalon Pro beingType Certificated with UK CAA) is no guarantee of anything. I say that specially to you because you are a big fan of certification. Crap I have seen in many certified airplanes leads me to the same conclusion.
The only good thing about certification is that it generally leads to a corrective action being forced upon the fleet.

 

[WaspAir]

If you read closely, you would find that I have no regard for Primary Category certification.

There has never been a Bensen-style rotor system aircraft approved for Standard Airworthiness.

 

[Abid]

If you read closely, you would find that I have no regard for Primary Category certification.

There has never been a Bensen-style rotor system aircraft approved for Standard Airworthiness.

True.
But Cavalon Pro is Type Certified in the UK also.
Also I am telling you crap I saw in CAR 4 certified airplane fleet as well. Things get missed. But they do get corrective action which becomes regulatory and mandated.
R22 and if I remember some early Bells were teetering rotors even if powered. Mast bumping isn’t unheard of in certified helicopters including in fatal accidents right here in Clearwater, Florida. You fly them wrong and you will get it.

 

[WaspAir]

I own a two-blade "teetering" Bell 47, but it has a swash plate, full collective and cyclic control, a stabilizer bar, etc., and would never be confused for a Bensen-type rotor (same goes for the semi-rigid R22). Nothing ensures perfect safety or idiot-proof piloting, but structural failures in Standard Airworthiness aircraft are really rare. The exceptions are typically after many thousands of hours of abuse in harsh environments, or you get disoriented in IMC, bust Vne by double, and pull the V-tail off your Bonanza. Mast bumping in Bells requires similar serious mishandling. Despite some Huey UH-1 disasters back in Viet Nam, I don't know of any model 47 mast bumping accidents. The last 47 fatality I recall was a 1953 model 47 used as a crop duster with 14,000 hours that suffered a catastrophic transmission separation in 2018.

 

[Abid]

About the structural failures. Certain clarification adds value

ELA Butt welds breaking off —. That is a process control issue.
ELA composite rotors getting cracks also a process control issue.

Artur Trendak AirCopter rotor cracking due to fatigue and also AutoGyro rotor system 1 getting fatigue cracking where hub bar clamps around the bolt. Both these rotor blades are copies of each other. AutoGyro literally copied them. This is am improper design issue leading to pre-mature fatigue and an overly optimistic fatigue life calculation. If you copy and know you copy and improve or you copy all the mistakes as well.

TAG carbon fiber rotor. That is also a process control issue.

AutoGyro gimbal block tearing itself apart at 1106 foot pounds of torque applied to it while it was at its travel stop. That is a design structural issue. It won’t happen in their earlier rotorhead. It was a miss and never expected or considered. Also machining down a weld to accommodate a washer That is a cardinal sun never allowed in aviation production. Welds should never be grounded.

Tango rotor coming apart. I am not sure. Maybe there was a previous flap or maybe there is sone deficiency in design or material. Maybe the guy trailered long distance with rotor in the mast causing many fatigue cycles. I don’t know. I just know that I saw sone scary stuff in the Tango frame and you will never catch me flying in one ever. That was enough for me.


So at least half were process control issues meaning production engineering and QA specially from ELA and TAG.

In upcoming ASTM standards we have standards not just for design but for QA and production as well as COS and others. Constructions norms like not grinding down welds are generally spelled out in the design standard but control of production processes are on the manufacturer and they have personnel required to sign off assemblies before closing. This is similar to what is required in a production certification. COS requires corrective action is released. Hopefully we can make companies claiming compliance to those standards better control their processes and do not do non standard construction things like grind r machine welds down.

 

[WaspAir]

Those are insightful details. Thanks.

 

[IgnacioParodi]

The largest one. AutoGyro. You saw the gimbal block tore itself apart in the UK accident and also seems like in Beverly, Mass accident.
They have had cracks in the rotor blades at one point because of incorrectly designed hub bar interface to hold the blades. In their new rotors again there have been cracks found in the UK I think (please correct if I am wrong).
AG has also has mast cracking around the weld where engine mounts. I have fixed a couple. I have seen that in Europe also.
They have had several prerotator brackets crack but they are not a flight risk.
They have had a few HTC prop blades delaminate including in the air in Texas and one suspected in Arizona. HTC props are made by AG themselves.

ELA has had tail booms break off at the butt welds causing fatal accidents in France and Spain. Not the Eclipse series though.
Seen cracks on two sets of ELA composite blades here in Florida. They were caught before they caused any issues in flight and changed.

Artur Trendak had rotor blade come apart in a Polish gyroplane accident killing my friend and former trike world champion and I believe also gyroplane European champ. They released an AD.

In an accident in Florida Tango gyroplanes Russian one rotor blade was seen coming off the gyro 400 feet away from where the gyro ended up.

TAG Australia gyro had carbon fiber blades whose tip weight inserts were not properly structurally glued in the blades so they slid all the way out in flight breaking the thin tip caps. That caused such horrendous vibrations that it caused the masts to break off. That would be expected with such vibrations. At first they thought it was the folding mast which I knew it couldn’t be. Then someone figured it out. That issue however has been fixed since then.
Added: I forgot someone did also post picture of a crashed TAG frame and complained that the welding on Titanium was bad because the break in mast to keel junction and another area was right in the middle of the TIG weld bead. That does sound correct to me. A proper penetration TIG weld should not break in the weld bead but right next to it due to shock load and impact. This was on one of the TAG gyroplanes that lost tip weight in the blade which caused the accident. So the weld breaking was not the cause of the accident just showed the improper low penetration of the weld.

I can’t think any other true structural failures in any current batch of production gyroplanes.

You are the man! I bow down

 

[BarryK]

Face it gentlemen…..any gyro is only as safe as the pilot flying them.
Be safe out there

 

[ARGON Producer]

In many failures of xenon derivatives, including DUTL tests, the mast breaks off because it is too stiff, and the weakest link is the connection. This alone negates most everything else. A rotating rotor in an accident that can break away on impact will go wherever it pleases, in a completely uncontrollable manner. If you want to claim that Argon is a better structure, fix it.

Abid, ARGON has a fully modified mast structure and the connection and introduction of forces into the composite (look pictures first 3 - ARGO , last XENON). ARGON has a full structural mast pocket that absorbs force from the mast both through the shear of the bolted connections and (mainly) through the friction of the mast surface against the composite structure. The mast pocket, together with the central tunnel, form the backbone of the load-bearing structure of the entire ARGON. The mast profile itself was designed based on a mathematical model to handle the maximum loads that the most demanding BUT and CAP certification processes predict. The mast is both strong and flexible (it has a milled side surface causing greater flexibility) , it does not “break away” only deform. During strength and fatigue tests it met all the imposed strengths and forces.

With all due respect, you are wrong on several facts.

XENON has never been certified in DULV only in DAeC.

Neither DAeC nor the Polish CAA ever “recommended” increasing mast stiffness. Celier was not an engineer in the sense of having a degree, but he was a brilliant designer, there were always engineers around him with degrees, but he could often “bend” them with the knowledge he had.

The mast in the Xenon was attached to the surface of the fire wall with angle brackets and inserted into a partial short pocket, and was made of a different profile and aluminum alloy, which combined to cause cracking in critical overloads.

Modgil Arun, the manufacturer of the American Ranger said that you also had a number of problems with the structure cracking, you are so eager to speak about other gyros, maybe you should also tell about your experience....