NZ Govt agencies ban the R44

What have you heard?
Gonsky
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Re: NZ Govt agencies ban the R44

Postby Gonsky » Sun Nov 6 2016, 00:34

Of course they don't do 120 hours and that is a good thing???? I am not going to even enter the moral debate for what a responsible adult should impose, yet one would think as many hours in as many different conditions possible would be a start. So 30 hrs on L's and then 5 hrs a week for 3 yrs, almost 500 hours for a 2 axis killing machine.

And your away in a 3 axis in no time, agree with safe pilots yet how many on his forum alone would ever say they are not a safe pilot.

Agree with some having higher skills sets and aptitude, I have seen pilots who view themselves as superior do real stupid stuff. There is no benchmark, everyone is different s**t happens.

This thread started with the Robinson and a very good paragraph by Saucepan and why there is the issue in NZ so much. Commercial pressure, training it had some good points.

A lot seem to defend an air frame that is causing grief to your industry, whether it is pilot or design or both that is yet to be determined. Some have pointed out that it is less forgiving and that is the issue.

Bottom line is as AgRattler pointed out if not suited for NZ then rates go up. If banned in one country then legal issues will bring problems for operators in others. Higher operating costs mean people will start looking at other ways to achieve the same outcome.

Regards,

Gregory
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Re: NZ Govt agencies ban the R44

Postby bigboynasty » Sun Nov 6 2016, 03:06

I have read with interest on this tread to see if the collective wisdom of the industry has found the root cause of the mast bump problem, so a solution can be found. It would seem to me that this hasn't been achieved in any positive way. It just seems to fall into the slanging match of what has been a fantastic machine for lots and lots of Pilots to learn inand gain valuable experience. NZ has a problem with Robinson products but the answer isn't,the well documented issues with a 2 blade machine but in the training of not only Pilots but also instructors.
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Re: NZ Govt agencies ban the R44

Postby Birdy » Sun Nov 6 2016, 04:29

I cant think of any situation where, with a competent pilot, mast bumping would be inevertable.
Ill gladly be corrected.
So if most of the NZ incidents are mast bumps, it took an incompertent pilot to get it into the situation that caused it.

Ham fisted cyclic rates with insufficiant power on causes mast bumps.
As i said earlier, the power assist in 44s mask to a degree the inertia resistance felt without it.
That resistance is the rotor telling you to backoff a tad.
Funny how the R66 hasnt been blackmarked.
Power increases in a piston machine can be as quick to respond as fast as you can twist the grip.
Turbines are not so snappy to respond, so all inputs are lagged, lowering the input rates of the pilot.
Lower input rates means the airframe has more time to follow the rotor, and not bump.

Im ready to be corrected, i love to learn.
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Re: NZ Govt agencies ban the R44

Postby Practice » Sun Nov 6 2016, 09:29

Im ready to be corrected, i love to learn.


You probably mean inevitable not
inevertable
:)

And incompetent, not "incompertent"... - Mod.
:)
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Re: NZ Govt agencies ban the R44

Postby bangequalsbad » Sun Nov 6 2016, 19:44

Hi Birdy.
Ham fisted cyclic rates with insufficiant power on causes mast bumps.
From memory it is the "unloading" of the main rotor system during negative-G situations and the subsequent induced roll of the tai rotor thrust that setup mast-bumping conditions. To complete the disaster, the pilot must make an input (gentle or violent...doesn't matter) to "correct" the roll WITHOUT LOADING THE DISC to actually contact the mast. The Robinson safety course does a pretty good job of explaining this, and the correct procedures for both AVOIDANCE and CORRECTION.

Funny how the R66 hasnt been blackmarked.
Not the numbers of them out there currently.

Turbines are not so snappy to respond, so all inputs are lagged, lowering the input rates of the pilot. Lower input rates means the airframe has more time to follow the rotor, and not bump.
As stated above, not the rate of the input that is important, it's the disk being "loaded" (positive-G) or "unloaded" (negative-g). If it was as simple as limiting the pilots input to the main rotor in all conditions, it would be a simple task of a few bolts and holes to reduce available movement to a degree required, and then you'll have to give yourself a bit more room to turn the machine.

On a slightly more mathematical route...does anybody have the main rotor shaft length (exposed above gearbox to rotor head attachment) for the 44,66 and 206? I'm suggesting that a longer driveshaft creates a longer lever, which while reacting slower to upsets, it also takes less effort to get it there. Combine that with say a light 44 airframe opposed to a lump of 206 and think about which one requires the most effort to get into negative-g to start with, and then proceed from there. It may well be that the 44 has a "bad" combination of forces that require more eduction, especially in difficult environmental conditions, and companies using this type have additional training on these factors provided to their pilots. It could also be that the 44 has a "good" combination of forces, and it is completely (without reference to any event, person, or situation specifically) the pilots who are at fault, regardless of the training or courses attended.

Also...I stand to be corrected ;)

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Re: NZ Govt agencies ban the R44

Postby County » Sun Nov 6 2016, 21:10

Every Helicopter has different characteristics, each has to be flown with that in mind. R44 is a great aircraft and still favoured by many operators here in OZ.
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Re: NZ Govt agencies ban the R44

Postby heliA1 » Mon Nov 7 2016, 08:24

I'm no instructor or engineer
How many people do a calculation prior to every flight in 44 it's so easy to go forward C of G as fuel burns off. Combine this with light airframe 700kg light on fuel then only 12 degrees of separation on mast and hub and bit of airspeed on hit bit of turbulence???Heard pilots loading backseats with weight for return flight home if turbulent.
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Re: NZ Govt agencies ban the R44

Postby Waka topatopa » Mon Nov 7 2016, 09:07

Birdy wrote:I cant think of any situation where, with a competent pilot, mast bumping would be inevertable.
Ill gladly be corrected.
So if most of the NZ incidents are mast bumps, it took an incompertent pilot to get it into the situation that caused it.

Ham fisted cyclic rates with insufficient power on causes mast bumps.
As i said earlier, the power assist in 44s mask to a degree the inertia resistance felt without it.
That resistance is the rotor telling you to backoff a tad.
Funny how the R66 hasnt been blackmarked.
Power increases in a piston machine can be as quick to respond as fast as you can twist the grip.
Turbines are not so snappy to respond, so all inputs are lagged, lowering the input rates of the pilot.
Lower input rates means the airframe has more time to follow the rotor, and not bump.

Im ready to be corrected, i love to learn.


Since you are ready....

Firstly.....why do some of the worlds top race car drivers crash.....are they incompetent drivers?

The reason mast bumping occurs is due to the right roll of the aircraft fuselage in relation to the rotor head in low G conditions.

This right roll is the result of a torque couple produced between the main rotor and the tail rotor.

Robinsons tall masts compared to other 2 bladed teetering systems like the Bell products and their more efficient tail rotors make things worse as do their light airframes. Look at crashes attributed to mast bumping and you'll find many of them were in lightly loaded machines. I won't even go into the difference in the crash worthiness of the airframes. After all the JR's were designed and built for the military and the Robinsons the daily commute.....

Low G and insufficient power doesn't make sense. More power= more left pedal which =more right roll in low G. And it's not only ham fisted inputs which cause low G....turbulence does a great job of it too and NZ gets its fair share of that. And before you point out the obvious it's not a case of windy day=lots of turbulence. Unexpected clear air turbulence isn't uncommon either and has caught the rapid attention of many an aviator.

The R66 isn't off the radar. I attended the Robinson factory safety course recently and they had just clocked over 10,000 hours with 8 fatals for which mast bumping was the most likely cause. Not surprising given it's a lighter airframe with more power going through it and the things want to fly fast too (another factor which is less than helpful when hitting unexpected potholes in the sky or not having the experience/training to pick areas of turbulence in the hills).

Mast bumping is definitely at the forefront the medias attention at present. But let's not forget also the posts crash fires and that 60 minutes doco produced in Aussie not so long ago that captured everyone's attention in regards to Robinson aircraft too....

I'm not jumping on the Robinson bagging band wagon. Like many on here I've flown them a fair amount including in some pretty windy conditions. They are no doubt a great helicopter when flown in the right manner in the right conditions. However, one must still admit they are made in such a way that they have been far too susceptible to dislpaying the result of design faults that have taken the lives of too many of our colleagues, friends and passengers despite the awareness training, safety notices, courses etc already in place.

As for the exit of the R44 increasing hourly rates in NZ....good luck with that when we already have a number operators charging less than acceptable R44 rates for H500's and JR's!
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Re: NZ Govt agencies ban the R44

Postby Evil Twin » Mon Nov 7 2016, 10:01

Waka topatopa wrote:
Birdy wrote:I cant think of any situation where, with a competent pilot, mast bumping would be inevertable.
Ill gladly be corrected.
So if most of the NZ incidents are mast bumps, it took an incompertent pilot to get it into the situation that caused it.

Ham fisted cyclic rates with insufficient power on causes mast bumps.
As i said earlier, the power assist in 44s mask to a degree the inertia resistance felt without it.
That resistance is the rotor telling you to backoff a tad.
Funny how the R66 hasnt been blackmarked.
Power increases in a piston machine can be as quick to respond as fast as you can twist the grip.
Turbines are not so snappy to respond, so all inputs are lagged, lowering the input rates of the pilot.
Lower input rates means the airframe has more time to follow the rotor, and not bump.

Im ready to be corrected, i love to learn.


Since you are ready....

Firstly.....why do some of the worlds top race car drivers crash.....are they incompetent drivers?

The reason mast bumping occurs is due to the right roll of the aircraft fuselage in relation to the rotor head in low G conditions.

This right roll is the result of a torque couple produced between the main rotor and the tail rotor.

Robinsons tall masts compared to other 2 bladed teetering systems like the Bell products and their more efficient tail rotors make things worse as do their light airframes. Look at crashes attributed to mast bumping and you'll find many of them were in lightly loaded machines. I won't even go into the difference in the crash worthiness of the airframes. After all the JR's were designed and built for the military and the Robinsons the daily commute.....

Low G and insufficient power doesn't make sense. More power= more left pedal which =more right roll in low G. And it's not only ham fisted inputs which cause low G....turbulence does a great job of it too and NZ gets its fair share of that. And before you point out the obvious it's not a case of windy day=lots of turbulence. Unexpected clear air turbulence isn't uncommon either and has caught the rapid attention of many an aviator.

The R66 isn't off the radar. I attended the Robinson factory safety course recently and they had just clocked over 10,000 hours with 8 fatals for which mast bumping was the most likely cause. Not surprising given it's a lighter airframe with more power going through it and the things want to fly fast too (another factor which is less than helpful when hitting unexpected potholes in the sky or not having the experience/training to pick areas of turbulence in the hills).

Mast bumping is definitely at the forefront the medias attention at present. But let's not forget also the posts crash fires and that 60 minutes doco produced in Aussie not so long ago that captured everyone's attention in regards to Robinson aircraft too....

I'm not jumping on the Robinson bagging band wagon. Like many on here I've flown them a fair amount including in some pretty windy conditions. They are no doubt a great helicopter when flown in the right manner in the right conditions. However, one must still admit they are made in such a way that they have been far too susceptible to dislpaying the result of design faults that have taken the lives of too many of our colleagues, friends and passengers despite the awareness training, safety notices, courses etc already in place.

As for the exit of the R44 increasing hourly rates in NZ....good luck with that when we already have a number operators charging less than acceptable R44 rates for H500's and JR's!



Well articulated bro.
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Re: NZ Govt agencies ban the R44

Postby Gonsky » Mon Nov 7 2016, 11:01

A long main shaft allows something like 12 degrees tethering in the case of a 44, a shorter main shaft would reduce that as a boom strike would occur. Therefore the hit on the main shaft would not be a severe if the tethering angle was less based on a shorter MS. Less hit means less separation.

Another point mentioned earlier is the leverage factor due to the longer shaft, the real point is because of that longer main shaft the ability for a serious bump is possible. If you had a 1 mtr shaft vs a 6 mtr shaft the stress and FOS would be completely different.

The one reason I have always hated and never trusted a 22,44 or 66 is the length of the main shaft. Bump is one issue the simple maths for a long shaft that a difference in the cg (chord/span) or mass of one blade will be magnified exponentially.

Washout is very important when it comes to blade dynamics, thin chord with little rigidity is not a good look but does not require much HP. A reflex blade that has less chance for laminar separation would be a far better design, something that could be perceived as a super critical added to a reflex could be a winner. Mostly it is a NACA 8 H -12 which is a flat bottomed general purpose air foil that has had its day, the 63-015 is not that flash either. This also has consequences on blade/disk loading.

NACA 64 series need to be looked at more carefully in blade design as do super critical air foils.

Regards,

Gregory
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Re: NZ Govt agencies ban the R44

Postby AgRattler » Mon Nov 7 2016, 21:05

Well said wakatopatopa. Some big words in there too!
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Re: NZ Govt agencies ban the R44

Postby agusta » Tue Nov 8 2016, 03:02

Bit off topic

If you encountered turbulence in a 44, if you chucked in a heap of right pedal and flew it out of balance would it be less likely to roll due to less torque?

(Im aware correct move is slowing the aircraft up and taking the long way)
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Re: NZ Govt agencies ban the R44

Postby zzodr » Tue Nov 8 2016, 04:10

History has a habit of repeating itself.
You can mast bump a Bell 47. Did they ban it? no. Saved 18,000+ lives in Korea.
You can mast bump a UH1. Did they ban the Huey? Hell no. They flew it in combat in some of the most demanding conditions for helicopter operations in Vietnam, and it saved the lives of countless people and still doing it today.

--
The Fort Worth Star-Telegram
Sunday, March 25, 1984

WASHINGTON — Nearly 250 U.S. servicemen have been killed since 1967 aboard Bell helicopters that crashed because of a design flaw that remains largely uncorrected even though the Army discovered it in 1973, according to military documents and former Pentagon safety experts.

The top lawyer at Bell Helicopter of Fort Worth acknowledged the seriousness of the matter in 1979 when he urged the company to fix the problem even if it had to spend its own money to do so.

"I consider this matter very serious and, if we do nothing about it, very likely to be the subject of attempts at punitive damages." George Galerstein, Bell's chief legal counsel, told company management in a 1979 internal memo.

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Re: NZ Govt agencies ban the R44

Postby Gonsky » Tue Nov 8 2016, 07:27

Tethering head is old school considering current capabilities.

Robinson as the #1 heli sales company should sort this. Many have said they are and yet they just fix s**t after the issue???

Many have said they are number 1 through sales yet they just had the right design at the right time hence the penetration into the market place, think of a 44 as a c note (us100$) no matter where you are you can always pass both of them. The tooling and global maintence setups make a huge differnce as you can be in the middle of nowher and you can get a robinson mec and pay him with us$$$ :D

Complete redesign on the fuse with CF and safety cell, less weight that can be pushed into the safety cell for PAX.

Redesign of main blades with different airfoils at root/mid/tip composite construction as well as TR blades. And get rid of that head.

Kevlar self sealing main tanks at least.

A few points that could make a huge difference.

Regards,

Gregory
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Re: NZ Govt agencies ban the R44

Postby godfather007 » Tue Nov 8 2016, 10:07

This topic is getting old.
Yes Robinson Helicopter Company need to look into redesigning the rotor head. Imagine if they incorporated an AS350 style upper structure, head and rotor system on the current airframes.(genius) Will they?
Don't hold your breath. Saving $. Maintaining a low operator purchase/running costs leads to increasing sales, that always has a swinging factor in any design, be it a lounge, car, all the way up to a helicopter. The trend is, If it works don't change it.
As far as I know, (happy to be corrected) Frank Robinson went about designing, building and selling the Robinson series helicopters with the average Joe having access to and being able to fly helicopters. (People like me)
His ambition was to bring an affordable helicopter to the general public ( for simple A-B flying) in the late 70,s after he worked for the big military helicopter suppliers. They thought his idea of the average joe being able to purchase and fly a helicopter in a private situation were not economically viable and the military market was the way to go for the best dividends. As a result, he has proved them wrong. Many private operators/ CPL H holders have lived the dream and many commercial operators world wide have prospered from the Robinson idealology.
Over the years, Frank has delt with the issues of his designs and the incompertant decisions that some PIC's have made.
Mast bumps, low RPM situations, electrical design floors, fuel tank issues, not sticking to normal procedures set out in the FM, low G.. The list goes on, just read the limitation, AD section and end of the fright manual of any RHC series helicopter. They are mainly based off fatal endings caused by poor PIC decision making and some design limitations that were not considered during the testing and approval stage of the type. (all manufactures have done the same)
I don't think Frank Robinson had any idea back in the early days that his designs would be out completing taskes up to and beyond there design limitations nor in some situations people dying as a result of outcomes mentioned above.
Choose the right tool for the job, fly the machine within its limitations and your ability.
I have and will continue to fly many R22 and R44 helicopters, moved into Squirrels, EC's, Bell 206, 407, Huey's, 300''s, 500's. They all have different limitations, price tags and capabilities. Clients will do ther best to dictate what type I fly based off $ (and so they should, they pay the $$) but when it comes down to the machinery capability for the task, doing the math, risk assessment and considering the weather conditions, I will only put my passengers and my bum in what I believe is the best tool for the job or decline the job.
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Re: NZ Govt agencies ban the R44

Postby Eric Hunt » Tue Nov 8 2016, 10:49

Gregory, there are a lot of factors involved in designing a helicopter, and the biggest one is PRICE.

Two blades are cheaper than 3 or 4. The head design is cheaper. It fits easily into a hangar.
If the aerofoil shape is symmetrical, the grips can be made lighter, because the forces that need to be restrained are smaller. The blade is cheaper to make. We all know that this is not the most efficient blade profile, but it does the job, within limits.

If the design change from a 22 to a 44 is minimal, the costs to get it certified are less. By extending the mast length, the cg range was able to be increased from a simple 2-seat calculation to a more complex 4-seat configuration. Mast bump is not unique to the Robinson family, it applies to any TEETERING (note the spelling) head. I lost 3 very good friends to a Huey with a mast bump back in '81.

So we have a cheaper machine capable of carrying 4 people. Extend it with a turbine and a few more changes and it is a 5-seater.

It isn't, and never was, a competitor with the AS 350 series. Compare the prices. And as long as you fly by the flight manual, you will not have a problem with it. However, if you behave like a d1ckh3ad it will bite you. The bites also apply to those who don't like recurrency training.
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Re: NZ Govt agencies ban the R44

Postby Birdy » Tue Nov 8 2016, 21:20

Two excellent posts. ( EH & GF).
Horses for corses.
Opperate every machine within its limits.
Always stay within your own limits.
Your the PIC, so take command.
If the air turns bad, land the damn thing, its a helicopter, it can land near anywhere.
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Re: NZ Govt agencies ban the R44

Postby arrrj » Wed Nov 9 2016, 10:50

Some great posts here. Eric's is short and sweet and correct. I have watched the thread with interest, and now that it has calmed down, I will comment.

I have 1,000 plus hours on 44's. Time in 66's, 206, 206L, EC120B, AS350 and A109 (no 22 time). Certainly not in the class of VF, Eric et al, but I have some idea of how to fly a helicopter.

My 44 time is mainly in Australia, but some time in NZ. I have flown 44's in nearly every state, and around the Snowy, Blue Mountains and Tassie mountains.

I do not like flying around the mountains in a 44 if it is breezy. I will NOT consider flying any two blade heli anywhere near the mountains in winds greater than 20 knots - it's just NO FLY for me. In a 44 if it is windy (bumpy) I don't pull more than 20" and nose up...even a slight climb. It takes longer but I get there. I generally fly "heavy" on fuel etc, as I like the 44 when it is heavier to fly, it is not so skittish. No need to load up dead weights, just get more fuel, and then get some more if you are flying a long way. This may be boring for some, but it has served me well. I have a mate with something like 20,000 hours, who flies a 206L a lot, and he agrees with me. If it is too windy and anywhere near the mountains, it is a no go. Squirrel or 109...knock yourself out, but no 2 blades.

I flew with a really hard core guy years ago just after I got my licence, a sort of private BFR, and he said only one thing to me of note. ALWAYS keep the main rotor loaded, no matter what machine you fly. That has stuck in my head, and I ensure that's how I fly. I have been to the Robbie safety course, met Tim Tucker (and chatted, mainly about wine...) and learned a bit. I am always keen to talk to the real guys, with real hours, and I learn from them. BS can provide this to younger blokes too, and no need to shout...let's help each other. I have been to the Robbie factory, even met Frank. For anyone that blindly knocks the brand, a visit to this pristine factory may change your mind. There is a reason that the 44 is the number one selling machine in the world, and it's not just price.

Mast bumping happens (and has happened) in all 2 blade machines - like many older blokes (I am 50 plus - let's say an older head :wink: ) I have read about it a lot. It may sound so innocuous, but it might as well be called "mast dead", because obviously you can't fix it, no matter how good you are.

The 66 is a different beast. I was one of the first to fly it in Aus, and one up it can be scary. The machine does not have the great big lump of metal (the engine) that the 44 does, to weigh it down, and it is a bloody rocket ship. I have a good mate that flies one a lot, probably done more hours than anyone else, and he and I always talk about never flying it light. One up, I would fly it full of fuel, and really watch my speed if flying in the mountains. 66 is a 130 knot machine all day...I would say 90 knots in extreme conditions for me !

On another note (and ducking for flack) VF would have no problem flying a 44 or 66, because clearly he knows how to fly a 2 blade machine in extreme conditions. An old jetty flying around the Himalayas is certainly not for me, but he did it without problem and at extreme heights. Remembering that one of the reasons the 206 feels "solid" is that it weighs a lot and performance suffers enormously as a result. All those door panels and other lovely stuff does nothing for safety or performance.

Also remember that all the machines need to be maintained properly, some famous 44 accidents in Aus were caused by poor maintenance, as much as poor flying.

Slow down, nose up and keep the rotor loaded.

Cheers,
Arrrj
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Re: NZ Govt agencies ban the R44

Postby Birdy » Wed Nov 9 2016, 11:36

Interested to know, if someone can help, some head limits on Robbies.
How much stop to stop teetering range ( degrees) on the 22,44 and how much cyclic range, fore n aft, right to left?
Thanks in adavance.
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Re: NZ Govt agencies ban the R44

Postby Crowman » Wed Nov 9 2016, 21:49

I don't see too many 44's in this video.

https://youtu.be/nm8iV_uiBsI

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