R22 & R44 blade delamination
NZ feedback
RotorSwede,
I was in NZ a few days ago, doing a Robbie course. Had a chance to listen to an engineer give an hour going over both the R22 and R44.
He was a great teacher, as he had many years of experience with Robbies.
When asked about the delaminations, the NZ industry has not seen any major problems, it seem the R44 has had a couple.
It may not be a serious problem, but unless the world Robinson community reports them to Frank and his team, and your local regulator, we will never know.
So please put pen to paper.....
The previous blade problems were showing up long before "the system" became aware. Again, the need to do the right thing and tell the right people.
As an aside, the new blades seemed to be well excepted, but the thinner skin was easily damaged, and bush pilots were now keeping well away from anthing that could fly up into the rotor.
The engineer showed us blade sections of old and new. Tapping with a small coin, it is very obvious the new blades are really "soft" and easily dented.
But despite these minor problems, the Robbies are very safe when you spend hours on international data. The older types have a much greater loss and fatal rate, according to ATSB stuff from OZ.
If anyone wants a copy of the data, just PM me. It is interesting reading.
Fly with a smile ........
I was in NZ a few days ago, doing a Robbie course. Had a chance to listen to an engineer give an hour going over both the R22 and R44.
He was a great teacher, as he had many years of experience with Robbies.
When asked about the delaminations, the NZ industry has not seen any major problems, it seem the R44 has had a couple.
It may not be a serious problem, but unless the world Robinson community reports them to Frank and his team, and your local regulator, we will never know.
So please put pen to paper.....
The previous blade problems were showing up long before "the system" became aware. Again, the need to do the right thing and tell the right people.
As an aside, the new blades seemed to be well excepted, but the thinner skin was easily damaged, and bush pilots were now keeping well away from anthing that could fly up into the rotor.
The engineer showed us blade sections of old and new. Tapping with a small coin, it is very obvious the new blades are really "soft" and easily dented.
But despite these minor problems, the Robbies are very safe when you spend hours on international data. The older types have a much greater loss and fatal rate, according to ATSB stuff from OZ.
If anyone wants a copy of the data, just PM me. It is interesting reading.
Fly with a smile ........
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here we go again,
one blade delamination in the territory and two more in western australia in the last three weeks.
all of these blades are in the 300 to 400 hours in service.
trying to get more photos and more specific details.
one blade delamination in the territory and two more in western australia in the last three weeks.
all of these blades are in the 300 to 400 hours in service.
trying to get more photos and more specific details.
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damn
To the ppl that have been long in the industry:
When would be the time for RHC to make some sort of official comment concearning this issue? If one would look back at the previous blade-issues with the RHC.
Is it still to many unknown parameters, or is it "strange" that there is no info either on their website or to customers or to national CAA.
Or is it not big enough?
Just concearned, I know one should read the statistics and so on, but this is starting to take the fun out of flying the R22. If you check the blades 100% visually before you take off and not fly for more than 2h in a row, can one be more sure that this **** won't happen during the time airborn? I would say the answer is "no", or ? How is one supposed to train for CPL with this in the back of ones head.
*sigh*
RS
When would be the time for RHC to make some sort of official comment concearning this issue? If one would look back at the previous blade-issues with the RHC.
Is it still to many unknown parameters, or is it "strange" that there is no info either on their website or to customers or to national CAA.
Or is it not big enough?
Just concearned, I know one should read the statistics and so on, but this is starting to take the fun out of flying the R22. If you check the blades 100% visually before you take off and not fly for more than 2h in a row, can one be more sure that this **** won't happen during the time airborn? I would say the answer is "no", or ? How is one supposed to train for CPL with this in the back of ones head.
*sigh*
RS
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please don't shoot the messenger, I read on a site once, which I will attempt to find, that the delamination problem is mainly located in Australia, the reason stated, was, due to hobbs being disconnected, services being forged, 1000 of hours being flown, by "ghost" pilots, all this in the severe environment, of scorching heat / dust etc, while mustering. Be interesting to see the delamination stats per country.
Maybe just Oz
Agree.
More research needed.
NZ being colder? May not have the alleged problem. But Oz heat, flies and more UV, seems to be getting a problem.
Reminder again - if you see problem tell the regulator via their whatever system to keep tabs.
Then we will al know the answer sooner.
imabell goodonya for chasing this up
More research needed.
NZ being colder? May not have the alleged problem. But Oz heat, flies and more UV, seems to be getting a problem.
Reminder again - if you see problem tell the regulator via their whatever system to keep tabs.
Then we will al know the answer sooner.
imabell goodonya for chasing this up
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Data logging
I find it amazing that light helicopters, where your life depends on correct data logging, have nothing more accurate than a Hobbs meter. And it's plainly obvious that this is easily corrupted.
Yet again, the age old problem of certification is probably causing loss of life. For sure, there are low cost electronic telemetry systems out there which can log the data accurately with no risk of corruption. But you're not allowed to fit them.
The temps in the outback of Oz are no different to the surface temps in some other locations on the planet. So, let's get real. This is a problem unique to the "operating environment" of Australia - and we need more data to ascertain if limits are being exceeded, hours ignored and paperwork forged or lacking.
RHC should insist that CASA force bush operators to fit telemetry for a trial period.
And then let's have it for the rest of the world. Because we'd all love to know what our hirers, instructors and students have been doing.......
Yet again, the age old problem of certification is probably causing loss of life. For sure, there are low cost electronic telemetry systems out there which can log the data accurately with no risk of corruption. But you're not allowed to fit them.
The temps in the outback of Oz are no different to the surface temps in some other locations on the planet. So, let's get real. This is a problem unique to the "operating environment" of Australia - and we need more data to ascertain if limits are being exceeded, hours ignored and paperwork forged or lacking.
RHC should insist that CASA force bush operators to fit telemetry for a trial period.
And then let's have it for the rest of the world. Because we'd all love to know what our hirers, instructors and students have been doing.......
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Eventually I found the link, great read, from someone who obviously knows whats gone on ?
http://brumbyhelicopters.com.au/auspage1.htm
http://brumbyhelicopters.com.au/auspage1.htm
Tango Victor the older model blade problems probably had somthing to do with under recording of hours but these new blades haven't been around long enough for that to be the problem. It seems to be occuring at 300 to 400 hours of age.
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Having not long ago returned from RHC maintenance course it was highlighted that the -4 blades skins (stainless) are now only a third the thickness of earlier (aluminium) blades. (.008 -v- .025 thou).
This reduction in skin thickness is very evident in the markedly differing (less tolerant) damage limits with the new blades. A bit of 'Hangar rash' is now enough to render a blade scrap. Be careful and treat them with respect. RHC reported they are doing good trade in MR blade sales due to carelessness.
This reduction in skin thickness is very evident in the markedly differing (less tolerant) damage limits with the new blades. A bit of 'Hangar rash' is now enough to render a blade scrap. Be careful and treat them with respect. RHC reported they are doing good trade in MR blade sales due to carelessness.
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here are a few photos of the latest blades.
there seems to be an indentation near the doubler on the first pic as well as the crack, hasn't been ascertained what the cause is.
the severe ripples on the 63" station of both blades is also a mystery as there is no impact damage evident at all anywhere on the blades.
the delamination is hard to see in the photograph.on the orange upper section but is easy to see in real life.
these blades are outside the batch numbers of the original problem blades so the base is widening.
they are just over 300 hours in service so please this problem has nothing to do with high temperatures or over running times or flies. or misuse.
the fact is that contrary to some writers opinions mustering machines flown by experienced pilots (most are) do not pull heaps of power all day long playing silly buggers in the trees. most pilots use minimal power at slower speeds and get the optimum performance at low power settings. (i fly with these pilots regularly). no-one is in a hurry.
there seems to be an indentation near the doubler on the first pic as well as the crack, hasn't been ascertained what the cause is.
the severe ripples on the 63" station of both blades is also a mystery as there is no impact damage evident at all anywhere on the blades.
the delamination is hard to see in the photograph.on the orange upper section but is easy to see in real life.
these blades are outside the batch numbers of the original problem blades so the base is widening.
they are just over 300 hours in service so please this problem has nothing to do with high temperatures or over running times or flies. or misuse.
the fact is that contrary to some writers opinions mustering machines flown by experienced pilots (most are) do not pull heaps of power all day long playing silly buggers in the trees. most pilots use minimal power at slower speeds and get the optimum performance at low power settings. (i fly with these pilots regularly). no-one is in a hurry.
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Really hard to see in the 1st and last pictures! If you get any that show it clearer, please put them up.
The ripples look downright wierd!
Anything that helps point to what we should be checking for every day is appreciated!
BW
The ripples look downright wierd!
Anything that helps point to what we should be checking for every day is appreciated!
BW
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Functional Description of a General Aviation Flight Event Recorder – Flight Minder.
A requirement / opportunity has been identified for improving safety and correctly allocating costs associated with operation of light aircraft and helicopters in the field of General Aviation.
Introduction
Without some form of basic "flight event" monitoring and recording mechanism, it is the responsibility of the pilot, to recognise and record all the events associated with a flight, some of which can affect the safety of the aircraft or the cost of the flight.
Such events may include the following, along with the time and location at which they occur :-
Engine start and stop
Taxiing start and stop
Take off / Landing
Very heavy landing
Engine over-speed (rotorcraft)
Rotor over-speed (rotorcraft)
An instrument has been developed specifically to identify and record such events. During development this instrument is has been referred to as “Flight Minder”.
Description of the Airborne Equipment
The airborne equipment comprises a small (140 x 90 x 40mm) rectangular module which houses a microprocessor based event recorder along with the associated sensors and interfaces. The module includes a non-volatile memory for storage of events, along with a “Smart” (memory) card reader / writer and an integral GPS receiver. An external “patch” antenna is required for the GPS receiver.
To simplify installation in the aircraft, electrical connections to the aircraft have been kept to a minimum. Installation in a fixed wing aircraft requires only a DC power connection via an approved circuit breaker and aircraft main switch. The airborne module will operate from 7 to 36 volts DC, and consumes an average of 100 milliamps at 12 volts.
Flight Events
Engine Start / Stop
The “engine running” condition is detected acoustically
Stationary /Taxiing / In Flight
Events related to aircraft speed, i.e. stationary, taxiing or “in flight”, are determined by an integral GPS module. Software routines within the microprocessor require that the aircraft speeds remains above or below the set thresholds for a given period of time, before recording a change of condition. GPS “Speed over the Ground” is used throughout, with no correction for wind speed being made.
Heavy Landing
Heavy landings are detected by an integral two axis accelerometer. The use of two axes allows the instrument to be mounted on either a horizontal or vertical surface. At “switch-on” the microprocessor determines which axis of the accelerometer is aligned vertically, and this axis is then used for measurement until the instrument is switched off. A “running average” of vertical acceleration is taken over several seconds. This average, plus a preset level, are used as a threshold against which to compare any sudden, large, transient changes in vertical acceleration. The level is chosen to represent a value which if exceeded would indicate that structural damage to the airframe may have occurred. For the accelerometer to provide reliable results, the Flight Minder must be securely attached to the aircraft.
Rotary Over Speeds
When installed within a helicopter, if the potentially dangerous conditions of engine or rotor over-speed are to be detected, then external, non contacting sensors are required to provide electrical impulses at a rate proportional to engine and rotor speed. Connection to these sensors is made via pins on the same connector as the power supply. A current limited supply of 12 volts DC for the sensors is also available on the same connector.
Data Recording
When any flight event is detected, the nature of the event, along with the time, date and location at which it occurred is stored as a record in an internal memory. The aircraft registration, Flight Minder ID, and if available pilot details are also appended to the record. The internal memory can store over 500 events, and will retain data after power has been removed from the instrument.
If a suitable “Smart” (memory) card has been inserted into the instrument, then events stored in the internal memory are also copied to the removable memory card as soon as possible.
The primary function of the removable memory card is as a medium by which recorded data relating to the flight can be transferred from the airborne instrument to ground based equipment for recording and further processing as required. A secondary function of the card is to provide details to the airborne instrument, relating to the flight. Such details may include the name of the pilot, the type of flight (dual / solo / instruction etc.) The removable memory card can also store over 500 events. It is envisaged that data would be transferred from the card to the ground based equipment at the end of each flight, or if more appropriate, at the end of each day. Records are not deleted from the internal memory, until they have been secured on the ground based equipment.
Depending on individual requirements, a single card can be used for the transfer of all records from the aircraft, or a separate card could be issued to each pilot. The latter method is preferred as this allows pilot details to be assigned to flight event records.
Ground Based Equipment
A suite of software has been developed to read and manipulate flight event records from the Smart Cards. This software is designed around the Microsoft Access database format.
Alan Kitching Electro-Technik
+44 1642 724932 [email protected]
A requirement / opportunity has been identified for improving safety and correctly allocating costs associated with operation of light aircraft and helicopters in the field of General Aviation.
Introduction
Without some form of basic "flight event" monitoring and recording mechanism, it is the responsibility of the pilot, to recognise and record all the events associated with a flight, some of which can affect the safety of the aircraft or the cost of the flight.
Such events may include the following, along with the time and location at which they occur :-
Engine start and stop
Taxiing start and stop
Take off / Landing
Very heavy landing
Engine over-speed (rotorcraft)
Rotor over-speed (rotorcraft)
An instrument has been developed specifically to identify and record such events. During development this instrument is has been referred to as “Flight Minder”.
Description of the Airborne Equipment
The airborne equipment comprises a small (140 x 90 x 40mm) rectangular module which houses a microprocessor based event recorder along with the associated sensors and interfaces. The module includes a non-volatile memory for storage of events, along with a “Smart” (memory) card reader / writer and an integral GPS receiver. An external “patch” antenna is required for the GPS receiver.
To simplify installation in the aircraft, electrical connections to the aircraft have been kept to a minimum. Installation in a fixed wing aircraft requires only a DC power connection via an approved circuit breaker and aircraft main switch. The airborne module will operate from 7 to 36 volts DC, and consumes an average of 100 milliamps at 12 volts.
Flight Events
Engine Start / Stop
The “engine running” condition is detected acoustically
Stationary /Taxiing / In Flight
Events related to aircraft speed, i.e. stationary, taxiing or “in flight”, are determined by an integral GPS module. Software routines within the microprocessor require that the aircraft speeds remains above or below the set thresholds for a given period of time, before recording a change of condition. GPS “Speed over the Ground” is used throughout, with no correction for wind speed being made.
Heavy Landing
Heavy landings are detected by an integral two axis accelerometer. The use of two axes allows the instrument to be mounted on either a horizontal or vertical surface. At “switch-on” the microprocessor determines which axis of the accelerometer is aligned vertically, and this axis is then used for measurement until the instrument is switched off. A “running average” of vertical acceleration is taken over several seconds. This average, plus a preset level, are used as a threshold against which to compare any sudden, large, transient changes in vertical acceleration. The level is chosen to represent a value which if exceeded would indicate that structural damage to the airframe may have occurred. For the accelerometer to provide reliable results, the Flight Minder must be securely attached to the aircraft.
Rotary Over Speeds
When installed within a helicopter, if the potentially dangerous conditions of engine or rotor over-speed are to be detected, then external, non contacting sensors are required to provide electrical impulses at a rate proportional to engine and rotor speed. Connection to these sensors is made via pins on the same connector as the power supply. A current limited supply of 12 volts DC for the sensors is also available on the same connector.
Data Recording
When any flight event is detected, the nature of the event, along with the time, date and location at which it occurred is stored as a record in an internal memory. The aircraft registration, Flight Minder ID, and if available pilot details are also appended to the record. The internal memory can store over 500 events, and will retain data after power has been removed from the instrument.
If a suitable “Smart” (memory) card has been inserted into the instrument, then events stored in the internal memory are also copied to the removable memory card as soon as possible.
The primary function of the removable memory card is as a medium by which recorded data relating to the flight can be transferred from the airborne instrument to ground based equipment for recording and further processing as required. A secondary function of the card is to provide details to the airborne instrument, relating to the flight. Such details may include the name of the pilot, the type of flight (dual / solo / instruction etc.) The removable memory card can also store over 500 events. It is envisaged that data would be transferred from the card to the ground based equipment at the end of each flight, or if more appropriate, at the end of each day. Records are not deleted from the internal memory, until they have been secured on the ground based equipment.
Depending on individual requirements, a single card can be used for the transfer of all records from the aircraft, or a separate card could be issued to each pilot. The latter method is preferred as this allows pilot details to be assigned to flight event records.
Ground Based Equipment
A suite of software has been developed to read and manipulate flight event records from the Smart Cards. This software is designed around the Microsoft Access database format.
Alan Kitching Electro-Technik
+44 1642 724932 [email protected]
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The blade problems occur in just a few hundred hours leading me to suggest the problem is design. I think operation in turbulence is a problem.
Because the R-22 does not have lead/lag blade hinges. Normally a teetering head doesnt have lead/lag hinges, instead it is built heavy to absorb the lead/lag. The very lightly built R-22 has coning (flapping) hinges to relieve coning bending but nothing to relieve lead/lag stress resulting from the independent flapping in sharp turbulence.
Just my opinion on this rumor network. Until someone explains how the lead/lead hinges are not needed, that is what I think.
slowrotor
Because the R-22 does not have lead/lag blade hinges. Normally a teetering head doesnt have lead/lag hinges, instead it is built heavy to absorb the lead/lag. The very lightly built R-22 has coning (flapping) hinges to relieve coning bending but nothing to relieve lead/lag stress resulting from the independent flapping in sharp turbulence.
Just my opinion on this rumor network. Until someone explains how the lead/lead hinges are not needed, that is what I think.
slowrotor
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Speculation.
As slowrotor say, the two outside hinges of the tri-hinge hub should relieve a portion of the out-of-plane blade flexing and thereby allow for lighter/weaker blades.
I understand that the desire of a 2-blade rotor to flex in-plane is absorbed by the long mast. At certain RRPMs, could a resonance come about between the low inertia rotor and the engine that would increase the in-plane stresses?
Again, just speculation.
As slowrotor say, the two outside hinges of the tri-hinge hub should relieve a portion of the out-of-plane blade flexing and thereby allow for lighter/weaker blades.
I understand that the desire of a 2-blade rotor to flex in-plane is absorbed by the long mast. At certain RRPMs, could a resonance come about between the low inertia rotor and the engine that would increase the in-plane stresses?
Again, just speculation.
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Originally Posted by slowrotor
The blade problems occur in just a few hundred hours leading me to suggest the problem is design. I think operation in turbulence is a problem.
Because the R-22 does not have lead/lag blade hinges. Normally a teetering head doesnt have lead/lag hinges, instead it is built heavy to absorb the lead/lag. The very lightly built R-22 has coning (flapping) hinges to relieve coning bending but nothing to relieve lead/lag stress resulting from the independent flapping in sharp turbulence.
Just my opinion on this rumor network. Until someone explains how the lead/lead hinges are not needed, that is what I think.
slowrotor
Because the R-22 does not have lead/lag blade hinges. Normally a teetering head doesnt have lead/lag hinges, instead it is built heavy to absorb the lead/lag. The very lightly built R-22 has coning (flapping) hinges to relieve coning bending but nothing to relieve lead/lag stress resulting from the independent flapping in sharp turbulence.
Just my opinion on this rumor network. Until someone explains how the lead/lead hinges are not needed, that is what I think.
slowrotor
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flimflam,
In a normal two blade teetering system like a Bell 47 or Hiller the blades are forced to flap as a unit. The hinges on a R-22 allow individual blades to flap alone when hitting a sharp gust. It has been known since Cierva invented the flapping hinge that a lead/lag hinge would be needed as well.(after he found his free to flap blades failed in lead/lag)
A hinge is a hinge no matter what it is called.
What prevents the R-22 "coning hinge" from working as a flapping hinge?
slowrotor
In a normal two blade teetering system like a Bell 47 or Hiller the blades are forced to flap as a unit. The hinges on a R-22 allow individual blades to flap alone when hitting a sharp gust. It has been known since Cierva invented the flapping hinge that a lead/lag hinge would be needed as well.(after he found his free to flap blades failed in lead/lag)
A hinge is a hinge no matter what it is called.
What prevents the R-22 "coning hinge" from working as a flapping hinge?
slowrotor
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Has anybody heard what robinson is saying on these delaminations. I have been told they are saying that it is paint cracks and not debonding ,am unsure of how accurate this information is. I have seen in person the same as the pictures of the cracks at the doubler. I fly a lot of 22 hours this time of year.
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these photo's are of the blade off a raven 2 in new zealand. about 910 hours in service.
the chalk hatched lines show the extent of the delamination under the doubler.
flimflam, the robbie head may look like it is underslung but it does not have the ability to rock like a true underslung head that has a gymbal and a yoke.
the gymbal allows the head to flap and the yoke, attached to the gymbal by pillow blocks, allows the blades to rock, relieving all of the hunting stresses on the grips. an effective design feature for two bladed systems.
the robbie head does not have this feature.
to me it looks like the lead and lag, (hunting), stresses are still taken up by the blades and maybe the root cause of the problem.
the chalk hatched lines show the extent of the delamination under the doubler.
flimflam, the robbie head may look like it is underslung but it does not have the ability to rock like a true underslung head that has a gymbal and a yoke.
the gymbal allows the head to flap and the yoke, attached to the gymbal by pillow blocks, allows the blades to rock, relieving all of the hunting stresses on the grips. an effective design feature for two bladed systems.
the robbie head does not have this feature.
to me it looks like the lead and lag, (hunting), stresses are still taken up by the blades and maybe the root cause of the problem.
Last edited by imabell; 21st May 2006 at 22:56.