ASRA new safety directive for TAG gyroplane.

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I would expect to see ductile overstress when the rotor hits something at flight rpm as it did in the Orange Airport crash.
The mast plates broke in flight.
What evidence is there that the rotor blades hit anything prior to that?
 
What evidence do you have that a rotor blade didn't hit something at flight rpm?

It seems unlikely to me that 3,000 pounds could pull a plate like that apart.
 
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Hosko, I think that Chris was trying to blame only the Forrest Beach crash on overloading (even though a decent rotor system would have handled that without failing, since they're designed to tolerate AUW at 3.5g plus a 50% reserve factor).

Regarding the Orange crash, the mast plates failed, despite no defects in the spec material (Grade 5 Titanium).
Bolt hole (mis)placement was no doubt a key factor, as others instantly opined last year.

I don't expect gracious acceptance of ASRA's determination by some, with a blizzard of emoticons to follow.
Or, crickets.




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I DID NOT SPECIFICALLY "tried to blame " the WA accident...on OVERLOADING! " ...Hosko took a GENERAL COMMENT by me OUT OF CONTEXT ...from a Facebook group discussion ...I was pointing out the multiple factors that make up MOST aviation accidents scenarios ...the "swiss-cheese" effect of multiple layers of factors! ......
I noted that it was irresponsible to push a gyro's loading & weight & balance ( especially by adding a 10 liter can of fuel up in a nose cone ,that was NOT designed to store anything ...- & could have interfered with operation of rudder pedals!).

Any loading out of datum plane ...in addition to a full load of fuel,pilot,passenger & cargo pods stuffed full of camping gear (& some more fuel cans? )SIGNIFICANTLY loading beyond MTOW that 's recommended in the POH issued with that model gyro! ...that HAS happened & HAS been BOASTED about right to the manufacturer! (There WAS NO finger pointing to WHICH gyro ...ASSUMPTIONS WERE MADE!) ....the illustration was made to note how a rotor could be put in an overspeed ...with a tight-turn in a very heavily loaded configuration!

MANY TAG rotors of the grounded serial# group have flown many safe hours ....WHAT events happened to the WA one @ about 150 hours service time...PRIOR to the day of accident ...to crack loose the weight rod from it's matrix????
During the TAG manufacturer's Australia & international November/December rounds in verifying the tail attachments - post the Orange accident ...many gyro's had rotor tuning done to ensure smooth rotors!
The WA gyro had smooth flying rotors after the tail verification visit...A short time after, they were then noted to becoming "rougher & rougher" & owner requesting Neil to come out & rebalance them...DAMMIT THAT rotor was telling it's owner SOMETHING abnormal was going on ..... NOT A HAPPY ROTOR! ...here we come to the human-factors of "swiss-cheese" layers that stack to allow (or Avert) a tragedy!

When you have a clearly unhappy rotor system ...it is INSANITY to add more load & go flying! (as in extra passenger) = ?????ADM & human factors ...that treads on "sensitive ground"! ...sadly a likely factor in another accident the same day - closer to our community!

In a separate incident ...a new TAG owner ...during an incorrect pre-rotation procedure ... managed to tear up his ring-gear! ( right in front of the manufacturer ...during rotor tuning!)...his "cavalier response & attitude" ...to learning about a different model machine by READING the detailed POH ..."NAH ...I never read those things ... just do it the way i always have!"

... how VERY discouraging for a diligent manufacturer who puts hours into producing GOOD supporting documentation / instructions! :oops:
 
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Some here seem confused about the difference between ATSB ( Aussie NTSB!) & the ASRA ...who have still not finalized their investigation & issued a final report!
Although I have information on the likely finding ... for the Orange accident ...I await the OFFICIAL ASRA report publication!

The metallurgical report as noted by our gyronews-spotter above was a support assistance to the ASRA investigation by the ATSB! ...I most certainly planned on posting the link ...but the forum was down yesterday!

"I don't expect gracious acceptance of ASRA's determination by some, with a blizzard of emoticons to follow.
Or, crickets." .......such fatuous remarks ...go a LONG way to winning friends & influence here !!!:eek: NOT! (Rancid crow ...coming up for someone!) .
OH BTW ...you missed one! ( a TAG crash/TAG information thread) ...where you should have slapped down the ATSB link ...just to be damn good & bloody SURE everyone reading about Titanium gyro's is well & truly INFORMED! ...go do it & save me the trouble!
 
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It seems unlikely to me that 3,000 pounds could pull a plate like that apart.
Vance, the plates are subject to more than mere tensile load, such as twisting during prerotation.
Not to mention the forces of flying.

Besides, you're not even accounting for the abysmal design of the straight-across bolt holes,
which both Jean-Claude and Doug Riley previously panned.



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I DID NOT SPECIFICALLY "tried to blame " the WA accident...on OVERLOADING! " ...Hosko took a GENERAL COMMENT by me OUT OF CONTEXT ...from a Facebook group discussion
Chris, I think readers are smart enough to recognize clear implication when they see it.
I.e., why even bring up overloading if you didn't think it pertained to that crash?


Any loading out of datum plane ...in addition to a full load of fuel,pilot,passenger & cargo pods stuffed full of camping gear (& some more fuel cans? )SIGNIFICANTLY loading beyond MTOW that 's recommended in the POH issued with that model gyro! ...that HAS happened & HAS been BOASTED about right to the manufacturer!
OK, I'll "play". Are you referring to pilots of either the Orange or Forrest Beach crash?
If not, then why mention it here?


....the illustration was made to note how a rotor could be put in an overspeed ...with a tight-turn in a very heavily loaded configuration!
Even in your scenario, rotor rpm would still be less than what it should have been designed for: UAW at 3.5g + 50% reserve factor.
The rrpm overspeed wouldn't be enough to have alone failed the mast plates.


I most certainly planned on posting the link ...but the forum was down yesterday!
Both Steve_UK and I managed to post about it yesterday.

Although I have information on the likely finding ... for the Orange accident ...I await the OFFICIAL ASRA report publication!
Odd that you all didn't wait last year before you meanwhile sent out thicker replacement mast plates.
Hosko rightfully called you on that.

Regards,
Kolibri
 
Results

"The ATSB examination undertook physical, microscopic and chemical analysis of the cheek plates. These examinations found that the plates had failed due to ductile overstress, commencing at the leading edge and progressing to the trailing edge (when oriented in the direction of travel). The plate’s dimensions and chemical composition were in accordance with manufacturer’s specifications and there was no evidence of any pre-existing defects".

So are they saying there were no stress cracks, crystallization,or other defects in the plates prior to the break \ Accident? if so the weight is now a suspect
Have had a helicopter blade so bad from new we could not wind the turbine up to ground idle, let alone flying RPM I am sure if we had it would have taken the head off, the tip was 100grams heavier than the other 3.
You only need to look at ground resonance to see the destructive power of uncontrolled vibration.

I tend to agree with K & others that the mast design may not be the best & bears a closer study
 
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Thanks, 500e.

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If that fat balance rod was migrating towards the end cap through centripetal force,
then it would have flown "
rougher & rougher ". But, if the rod's original placement
were flush with the end cap, then it had nowhere to move (unless/until it exited).

Point being, who knows why that rotor lost its former smoothness, or how bad it had gotten.
Many gyros flying have distracting rotor imbalance, though probably not to the level of actual peril.
Nonetheless, it's still advisable to balance and track as well as possible.
 
Ductile overstress means it failed because it was pulled apart.

In the report there was no evidence of preexisting defects.

That suggests to me a force well outside the normal flight envelope.
 
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That suggests to me a force well outside the normal flight envelope.
< sigh > lol < sigh >
Ah, Vance, you blithely presume a well-designed part.
I mean, really, c'mon. Have you actually looked at these plates and their "
Erector-set " bolt holes?
Even TAG implicitly admitted their weakness by quickly replacing them with thicker ones after the 31 Oct 2018 Orange crash.

Are all gyro kit manufacturers safe with you?
For the uninformed newbie reading your posts, any gyro is just as robust as the other.
 
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"Even TAG implicitly admitted their weakness by quickly replacing them with thicker ones after the 31 Oct 2018 Orange crash."
WRONG & VERY INCORRECT!


A bit of information to the sensible readers! (the denigrators & persnikitey-pickers ..CAN & WILL spin most everything I say ..THEIR WAY! o_O) .....I'm here for clarity & not to engage in futile "king-of-the-hill" word games!

TAG management approached ASRA ...with the plan to produce revised fold-mast plates .....at no cost to customers to allow them to return to flying . ASRA allowed that this was a viable method to return machines to flight-status & as coroners inquests take 1-2 years & the complexity of ALL the evidence gathered in the Orange accident made this ASRA investigation looking like a long one! - ASRA appreciated the wisdom in not tempting pilots to take risks until the report was finalized!

The metallurgy & indépendant stress tests & have shown the original fold mast plates ( with all their "idiot-holes") ... to be MORE than adequate for the application in normal flight regimes! ( OUR 3 USA machines with fold-mast-original plates have over 800 hours ...showing NO wear/stress when replaced with NEW upgrade plates)
THE NEW plates tested 4 times stronger!

There are multiple "human-factors" associated with BOTH Orange & WA accidents ...& any mention of them is too sensitive to discuss with specifics ... SO I try to illustrate "scenarios" with several known non-specific examples of questionable ADM! "IMPLICATION" >>>is just the reader's perception ...we are ALL on the SAME TEAM here to see improved gyro-flight understanding, safety & develop disciplined professional attitudes replacing the "cavalier cowboy" attitudes that have brought too many tragic ends!



YES ...even wonderfully stable "big-tail-way-back" ...modern design gyros can be put into a flight profile that causes rapid rotor speed decay & HS rotor flapping, chopping off tails in flight & over stressing mast components! ( The weakest link of the rotor-system WILL break "in ductile OVERSTRESS!) ...if the masts had been solid ....we can only guess where they would have torn apart!

BTW I am currently in a very different time zone & hemisphere ...so was not hovering"breathlessly" to post the ATSB report the minute RWF came live again!

:sleep:
 
"Even in your scenario, rotor rpm would still be less than what it should have been designed for: UAW at 3.5g + 50% reserve factor."

As near as I can calculate The Predator at 4,900 pounds (all up weight of 1,400 pounds times 3.5 with no reserve) would have a rotor rpm of 694.

In my opinion this is well beyond the design limits of her Sport Rotors.

I mention this to point out that some people use language that they don’t understand to pretend they know more about engineering than the engineers.
 
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The metallurgy & indépendant stress tests & have shown the original fold mast plates ( with all their "idiot-holes") ... to be MORE than adequate for the application in normal flight regimes!
TAG management approached ASRA ...with the plan to produce revised fold-mast plates
Chris, then why revise them if they were always "MORE than adequate for the application in normal flight regimes"?
TAG can't have it both ways.

But, you're apparently aware of that, hence your current hinting at multiple "
human-factors":
There are multiple "human-factors" associated with BOTH Orange & WA accidents ...& any mention of them is too sensitive to discuss with specifics ... SO I try to illustrate "scenarios" with several known non-specific examples of questionable ADM!
. . . while trying to deny that you're blaming the pilots by disingenuously claiming that your non-specific "scenarios" are not meant to actually imply what you think may have been pilot error in these two crashes.

You're not fooling anyone with your <
wink, wink, nudge, nudge >.

Regarding the Orange crash, you've not at all mentioned the theory down-under of the tail having detached in flight, and due to something regarding the nut-plates.

I do not believe that a gyro's mast or rotor should fail from a tail strike or tail loss. Period.
YMMV, but you'll be sorry if it does.



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As near as I can calculate The Predator at 4,900 pounds (all up weight of 1,400 pounds times 3.5 with no reserve) would have a rotor rpm of 694.
Vance, Sport Rotors are available in 9"x31' which safely lift the MTOW 1700 lb SC2 in vigorous aerobatic flight, which includes spike g-forces in excess of 3.5 according Jim's g-meter.

The formula I quoted of MTOW weight at 3.5g plus a 50% safety factor is one for tensile testing, used by AutoGyro.
Your 1400 lb gyro with only 8.5"x30' Sport Rotors are probably of marginal size, thus your normal rrpm is higher than necessary.
So, assuming that your math is correct, it may be based upon an undersized/overspinning rotor.

Nonetheless, your own rrpm figure is moot: you're not going to pull them apart no matter what you do.
I'd be more concerned with your rigid mast.


In my opinion this [694 rrpm] is well beyond the design limits of her Sport Rotors.
Based on what evidence? I doubt that you conferred with Sport Copter before posting such unflattering opinion.

AutoGyro's discredited RS1 had calculated its MTOW 500kg @3.5g
to generate 687 rotor rpm. (RS2 figures are 638 rrpm.)
I never read any disbelief of yours about their rotor tensile strength.



I mention this to point out that some people use language that they don’t understand to pretend they know more about engineering than the engineers.
You claimed to have run some sort of engineering consulting firm.
So, what's your opinion of the TAG mast plates' straight-across bolt hole pattern?
Is that sound engineering?
Two here other than I say that it is not.
 
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I have had several long conversations with Jim Vanek about the suitability of the rotors on The Predator. He feels they are appropriately sized and the rotor rpm limits he shared with me are 275 minimum to 475 maximum.

I am sorry you missed the point.
 
and the rotor rpm limits he shared with me are 275 minimum to 475 maximum
I'm sorry that you missed the point with him.
Those are min-max normal flight rrpms, not an indication of how much more Sport Rotors could actually handle.

Also, you've frequently described your own "
poor memory", so I'll take that into consideration regarding your recollection of size suitability.
I'd wager that Jim thought 8.5"x30' was marginal back then for MTOW 1400 lbs and hard flying.
(9" chord Sport Rotors are another ~$3,000.)

Speaking of wagers, I'm also confident that 1400 lbs @ 3.5g rrpm is well within the tensile strength of 8.5"x30' Sport Rotors.
 
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kolibri
I think that the statement is somewhat unfair,
"Even TAG implicitly admitted their weakness by quickly replacing them with thicker ones after the 31 Oct 2018 Orange crash".

My take on the replacements are they found a break, remember the ASAR report
"there was no evidence of any pre-existing defects". & decided to beef up their existing plates to give existing customers a belt & bracer's item. (over engineered)
The Co seem to be upfront & have shown concern regarding the alleged loss of balance\blade weight, as you say if the weight is at the extreme tip of the blade if it comes loose the first thing you will know is Massive vibration followed by something else breaking is my guess.
Even if it is not at the tip & it starts to move how long before it exits, this could be a worse case as it has time to gain momentum before it hits the end plate.
The weights on 500s 300s are screwed into the leading edge spar the Enstrom also has a threaded cap the weights are fitted to.
These are no the weight or size of the suggested missing item.
My preference would be for some mechanical form of locking as well as the glue,
 
kolibri
I think that the statement is somewhat unfair,
"Even TAG implicitly admitted their weakness by quickly replacing them with thicker ones after the 31 Oct 2018 Orange crash".
500e, I understand your point: that their replacement was of the "over engineered" rationale (while maintaining faith that the original plates were not truly a safety issue). Perhaps that was indeed their mindset; I don't know. I'm not alleging their recognition of culpability.

ASRA's relevant sentence:

The plate’s dimensions and chemical composition were in accordance with manufacturer’s specifications
and there was no evidence of any pre-existing defects.

There are two ways to read that: the way you did (no pre-existing defects [before the crash]),
or, how the sentence naturally suggests to me (no pre-existing [
manufacturing] defects) given the previous mention of mfg. specs.

The original mast plates weren't up to handling the imbalance from blade failure.
Other gyro kit mfg. mast plates have remained intact with complete loss of blades, or flight rotor rpm impacts.
Retreating blade stall, tail strike, tail loss, overweight, whatever . . . the mast and rotor system must remain intact.
Nothing like the Orange crash should have happened.

______
Regarding the possibly ejected balance rod (smooth rod for poor epoxy bond; no mechanical securing at all),
this was a case of both bad engineering and/or production quality assurance.
Nothing like the Forrest Beach crash should have happened, either.

Regards,
Kolibri
 
When people fork out serious $'s for a gyro they are naturally distressed to have their machines grounded!.
Customer service, in-house information & honest disclosure with judicious return-to-service of the fleet ...are important !

When a precautionary grounding order is placed on a fleet (or sub-set of a fleet) ...due to an accident ....that will take many many months to have reports published ....a manufacturer who has access to a lot more information than can be publicly discussed after the initial investigation & before the final report is published...can take the option of redesigning a component and essentially create a "new model" ...(this of course contingent on engineer tested assessment of the new component) - DONE!

As 500e ... correctly called YOU OUT ...on YOUR unfair statement ...TAG Aviation DID not implicate their original design was faulty or culpable (in redesigning the mast plates) - just giving customers an option to return their gyro to flight status ...sooner than much much later ...awaiting an ASRA lifting of the grounding order - specific to originally equipped gyro's).....& in light of the ATSB (NOT to be confused with ASRA) metallurgy report ...feel justified that that the original design WAS PROVEN ADEQUATE!

HAD the WA gyro owner installed the NEW plates & the accident proceeded as it did ...no question the company would be in DEEP 💩 !

With the computer-modeling available these days ... it would be interesting to run some simulations!

I don't know how you think ANY rotorcraft mast system can be designed to withstand the MASSIVE out-of-balance forces PROVEN over & over to trash the craft in seconds ...when weight is unevenly added( Ice) or subtracted( loss of a balance component - or piece of rotor)! :rolleyes:

SO ...we await the ASRA reports -& wait & wait & wait! ......for full disclosure of ALL the factors culminating in these tragedies!

Meantime ... the "REAL POSSIBILITY" of a suspected rotor balance weight departure from the rotor in flight( in the WA accident) has grounded most of the fleet world-wide ...while a solution is being engineered to refit those rotors back to original specs (with leadshot-in-resin...along the leading edge!)

The culpable party in the rotor fiasco ...is the separate entity that produces ONLY the ROTOR ....AND ...ignored a specific direction from the TAG manufacturer ...when requesting a change of weighting material being laid up in the leading edge!

Everyone is working together ...doing their best to fix an engineering mistake (fortuitously discovered after the WA accident & time will tell IF it had a significant role in the accident "swiss-cheese" stack!) ...and getting TAG owners, CFI's, musterers & sport fliers back to work & play - SAFELY & ASAP!
 
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I cannot believe that meany \ any mast can cope with blade loss at flight RPM
I guess I should have landed immediately.....
Just noticed your post My answer is YES & if it was doing it before take off I am lost for words
 
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Anyone who is well aquainted with the TAG designer/manufacturer/"rotor-whisperer" ...OR has flown with me @ US meets in my demo units, OR who owns one of the other 50 odd TAG gyro's happily flying ..."OUT THERE" is well aware of what nice flying rotors the TAG design CAN BE!!!

Each rotor is flown & balanced smooth-flying before shipping OS or delivery to Aussie customers!

The composite rotor does have some "memory" ...so we TAG owners have all noted ..WHEN it sits at rest for a time .it does take a few minutes (about15) to relax into it's flight shape & smooth out during the first minutes of a flight ! (- after some degree of initial shake & perceived roughness in the stick!)

The manufacturer also has learned over time & experience with this new design of rotor that a little tune-up balance-work of his rotors at about 25 hours in service is beneficial to maintain the smooth flight profile as this is the nature of the composite rotor vs aluminum rotors!

With increasing time in service & different climatic conditions of the machines home-environment ... we all learn more about how these new type of rotors react over time ...IN FIELD conditions!

Neil has spent plenty of time traveling extensively with follow-up rotor tuning ...when a customer requests NICELY!

Neil is very positive & supporting of all his customers ...even the 1in50 who utilizes social media & public forums to "stick his vindictive boot in" ...with his grievances & need for attention!

The TAG carbon-on carbon spar rotor is unique new design & use of the aerospace materials ... there IS a learning curve of their characteristics ...under field & multiple environment conditions ...just as rotax engines can only do just so much testing in the factory lab & limited field trials ...it's only when their NEW designs go out in the general larger aviation population for real-life operation that new issues show up!

Remember ...all the rotax recalls in recent years ..for "manufacturing defects" ...in floats, fuel pumps, turbo's ...etc no matter how rigorous their quality control & in house testing ... the contracted "out-of-house" components ...still show up with "deviations from manufacturing specs" ...or however they word it! ....after a time under "real-life /fleet-hours " operation!

Aviation ...by nature is unforgiving ..when things go wrong ...everyone's best intentions can be damned in an instant ...when fatalities happen!
This is why we need to keep vigilant and disciplined ...in our YAWF( You,Aircraft,Weather,Flightplan ) checklists, personal "IMSAFE pilot readiness to fly list, manufacturer's upgrades installed, grounding notices complied with ... AWARENESS OF ALL the swiss-cheese layers that can line-up to make an accident happen! (or NOT!)
 
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The composite rotor does have some "memory" ...so we TAG owners have all noted ..WHEN it sits at rest for a time .it does take a few minutes (about15) to relax into it's flight shape & smooth out during the first minutes of a flight ! (- after some degree of initial shake & perceived roughness in the stick!)

It is common for older technology rotor blades with wood components to take a "set" if left drooping unsupported for too long, and fly accordingly for a while. For those blades, the best way to cope with that annoyance is to put a stand under each tip to support the weight while sitting in the hangar and going through temp and humidity changes. Being supported at both the hub and the tip makes a big difference. I wonder if that might positively affect the behavior you see.
 
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