Track and Balance Troubles
Did AW/Leonardo plagarise, or ask permission to use?
AW also do the BEST static balance job on their rotor blades. I don't know what they use for blade static balancing or how they do it, but they do a damn fine job of it. As do RBI (or whatever they're called now) as they also repair and balance AW139 blades.
Those blades will easily fly on any 139. The worst I've had is a botched job that took a couple of flights to figure out that the inboard and outboard tabs were in opposite directions!
Took Pitch Links and Tabs to nominal, emptied out all the weight and had it below 0.1 IPS from FPOG to VNE in three flights. The third flight was to confirm that HUMS was actually correct with the prediction.
That has to have something to do with how well the static is done.
I'm not going to comment on 500's. I used to try and avoid them as much as possible!
Cheers.
AW also do the BEST static balance job on their rotor blades. I don't know what they use for blade static balancing or how they do it, but they do a damn fine job of it. As do RBI (or whatever they're called now) as they also repair and balance AW139 blades.
Those blades will easily fly on any 139. The worst I've had is a botched job that took a couple of flights to figure out that the inboard and outboard tabs were in opposite directions!
Took Pitch Links and Tabs to nominal, emptied out all the weight and had it below 0.1 IPS from FPOG to VNE in three flights. The third flight was to confirm that HUMS was actually correct with the prediction.
That has to have something to do with how well the static is done.
I'm not going to comment on 500's. I used to try and avoid them as much as possible!
Cheers.
A well tracked 500 is one of the smoothest aircraft out there, but it can take some time and practice. We had a 500 come to us for a Cof A that had been maintained elsewhere.
It was decided to carry out the airtest prior to maintenance. The vibration level was so bad that the airtest was abandoned. As part of the process it was tracked and balanced with the old vibrex system.
The owner came to collect it, took off flew a circuit, and came straight back.
He just couldn't believe how smooth it was. Apparently the previous maintenance company had told him that 500's vibrated much worse than a 206 and he had just accepted what they said.
Over the years I have found that the biggest problem normally lies with the skill level and the lack of knowledge of the individual doing the job. On commercial operations throw in time and crew availabilty.
I remember my first day on the North Sea with Bond. Job to do was tracking and balancing a 105. Thinking I was going to the leading edge of the helicopter business I was horrified to be told that we would wait for dark as "the chadwick doesn't work in daylight".
I soon found out why they had this problem. They were using the dolls eye reflectors supplied by MBB which were not compatible with the chadwick gear. This carried on for some time (as nobody was interested in what I had to say) until the vibrex packed up and the rep from Environmental Equipment (who I knew) came up from Coventry. I cornered him before he got into the hangar and told him what was going on. He produced a set of of reflectors and all was well. As the aircraft was starting up for a tracking run I turned to the quality manager and said that I had used this type of reflector on 500's and they were great. He snarled at me "HOW DO YOU KNOW ITS THE SAME ON A BOLKOW" and walked off.
Pretty much summed up the attitude and why the 105's were shaking to bits.
Oddly enough a few years later I had to use the MBB supplied gear and the dolls eyes on a job in Africa. Worked fine in daylight!!!!
It was decided to carry out the airtest prior to maintenance. The vibration level was so bad that the airtest was abandoned. As part of the process it was tracked and balanced with the old vibrex system.
The owner came to collect it, took off flew a circuit, and came straight back.
He just couldn't believe how smooth it was. Apparently the previous maintenance company had told him that 500's vibrated much worse than a 206 and he had just accepted what they said.
Over the years I have found that the biggest problem normally lies with the skill level and the lack of knowledge of the individual doing the job. On commercial operations throw in time and crew availabilty.
I remember my first day on the North Sea with Bond. Job to do was tracking and balancing a 105. Thinking I was going to the leading edge of the helicopter business I was horrified to be told that we would wait for dark as "the chadwick doesn't work in daylight".
I soon found out why they had this problem. They were using the dolls eye reflectors supplied by MBB which were not compatible with the chadwick gear. This carried on for some time (as nobody was interested in what I had to say) until the vibrex packed up and the rep from Environmental Equipment (who I knew) came up from Coventry. I cornered him before he got into the hangar and told him what was going on. He produced a set of of reflectors and all was well. As the aircraft was starting up for a tracking run I turned to the quality manager and said that I had used this type of reflector on 500's and they were great. He snarled at me "HOW DO YOU KNOW ITS THE SAME ON A BOLKOW" and walked off.
Pretty much summed up the attitude and why the 105's were shaking to bits.
Oddly enough a few years later I had to use the MBB supplied gear and the dolls eyes on a job in Africa. Worked fine in daylight!!!!
Last edited by ericferret; 20th Mar 2017 at 12:58.
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500e,
Appreciate your support.....totally agree with you.
Nooby, If you are talking about RBI in Dubai they use the same Static Balance approach as does Avion....just that Avion made it much earlier than RBI did and is probably backed by a little more research. RBI built theirs themselves if I'm not mistaken. However I think you will find the Avion USBF far more flexible and operator friendly.....useable on any hangar floor or flight line not requiring air conditioned environments tor draft free area.
All I strongly suggest is you do the research and tell me who is correct.
To clarify the your inference that AW/Leonardo sought permission I am prepared to stand on stack of bibles and can prove one of their engineers in Apr 2008 downloaded the same information from the web site. AW even admitted to it in email to the offence and said they would change their documentation. If you like I can email you the letter of demand and their email replies if you remain of the belief they sort permission.....far from it....
Be very very careful about believing in OEMs as if they are Gods. Don't believe all the information they release as unchallengeable facts or unassailable truths....they are after all, protecting their bottom line. Treat everything with healthy scepticism and always ask that magic question.........."why"....then wait for the answer and ask if it makes sense or is it B/S..t.
Once again....read the web sites and tell me I'm wrong.
Sorry to Steve for highjacking your thread...I hope you have got some info to help you with your original Q ref the types and the equipment you mentioned
Cheers
RG
Appreciate your support.....totally agree with you.
Nooby, If you are talking about RBI in Dubai they use the same Static Balance approach as does Avion....just that Avion made it much earlier than RBI did and is probably backed by a little more research. RBI built theirs themselves if I'm not mistaken. However I think you will find the Avion USBF far more flexible and operator friendly.....useable on any hangar floor or flight line not requiring air conditioned environments tor draft free area.
All I strongly suggest is you do the research and tell me who is correct.
To clarify the your inference that AW/Leonardo sought permission I am prepared to stand on stack of bibles and can prove one of their engineers in Apr 2008 downloaded the same information from the web site. AW even admitted to it in email to the offence and said they would change their documentation. If you like I can email you the letter of demand and their email replies if you remain of the belief they sort permission.....far from it....
Be very very careful about believing in OEMs as if they are Gods. Don't believe all the information they release as unchallengeable facts or unassailable truths....they are after all, protecting their bottom line. Treat everything with healthy scepticism and always ask that magic question.........."why"....then wait for the answer and ask if it makes sense or is it B/S..t.
Once again....read the web sites and tell me I'm wrong.
Sorry to Steve for highjacking your thread...I hope you have got some info to help you with your original Q ref the types and the equipment you mentioned
Cheers
RG
Also what problems you are experiencing with RADS or Chadwick in balancing these aircraft.
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I know this is a long shot with this thread being years old. But I am looking for Track/balance info for the UH-60A, I cannot find any old Chadwick charts for it anywhere, I'm assuming they are somewhere out there, considering these were designed in the early 70's. I have current manuals. But they only seem to reference following the modern computers. And I cannot find tracking data from before all these computers. If anyone knows of any or could point me in the right direction, I would greatly appreciate it!
Thanks
Thanks
I know this is a long shot with this thread being years old. But I am looking for Track/balance info for the UH-60A, I cannot find any old Chadwick charts for it anywhere, I'm assuming they are somewhere out there, considering these were designed in the early 70's. I have current manuals. But they only seem to reference following the modern computers. And I cannot find tracking data from before all these computers. If anyone knows of any or could point me in the right direction, I would greatly appreciate it!
Thanks
Thanks
With various T&B kit and hardware installation it's more simpler to draw up your own charts after each adjustment to see what is happening.
Very rarely does the kit get installed exactly as per MM in our case as we use various kit across a mixed fleet with local made installation hardware.
Easier to figure out it manually based on position of optical pick up /mag pick/accelerometers / direction of rotation etc and see what effect a weight move has after obtaining a good track on ground and hover with PCL and maybe tab in hover depending on aircraft type.
Get track in on ground and hover, then go for lateral and vertical in flight.
Every adjustment will have an effect on all channels but after a few flights you can usually start establishing a pattern and plot your own chart.
Some of the newer kit will "learn" the moves but on a basic level.
Make one or two "big moves" to start with and establish the pattern and go from there.
Tab moves more sensitive at speed so do those with a little finesse.
We use:
Chadwick 2000
ACES
Dynavibe
Microvib II
Don't ask why we have such a mixed kit, I couldn't answer.
ACES the best out of all of them for learning the moves.
Dynavibe good for raw data and accurate track.
Microvib II reserving judgement on but also good for raw data. Crappy user interface though.
Fleet 206/206L's/212/Lama and MD500E.
MD500E is a bitch and usually upto five flights to get smooth with Dynavibe as tab adjustment is very finnikey. Most was eight flights to get below 0.1 L/V.
Good luck.
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Hi Glock,
This is a little late, but hope you have had success with your UH60 RTB problem.
The ref that Cyclic provided should provide a good basis to do the basic RTB. If the blades and machine are in reasonable shape then the procedures outlined therein be pretty straight forward...just print off the charts and worksheets and go for it.
Don't want to tell you to suck eggs, but not sure of how much experience on Uh60s you may have. Just be advised that the 4 per rev tuning is different to the RTB but commonly carried in conjunction with the RTB. But the first priority is to get the RTB within limits first.
Often, as the main rotor became smoother and below 0.1 IPS, it often made the 4 per rev vibes much more noticeable to the point of thinking that the machine is actually getting rougher.. This link may help
https://www.rwas.com.au/rotor-track-and-balance-rtb/
Scroll down to "Nper Rev Vibration"
Also if the blades are getting some time up on them and depending on their service history, be cautious if the move lines begin to move tangentially rather than close to parallel to expected move lines i.e. if the move line doesn't track toward the zero origin but moves tangentially past the origin and the minimum achievable vibe level is still excessive (>0.2/0.25ips) It may indicate a span moment mis-match which may need the blades to be statically balanced and tip weights adjusted. to bring the span moment back within limits.
See this link for explaination:
https://www.rwas.com.au/the-blade-problem/
I will PM you a guide on how to create you own polar chart if all else fails....
cheers
RG
This is a little late, but hope you have had success with your UH60 RTB problem.
The ref that Cyclic provided should provide a good basis to do the basic RTB. If the blades and machine are in reasonable shape then the procedures outlined therein be pretty straight forward...just print off the charts and worksheets and go for it.
Don't want to tell you to suck eggs, but not sure of how much experience on Uh60s you may have. Just be advised that the 4 per rev tuning is different to the RTB but commonly carried in conjunction with the RTB. But the first priority is to get the RTB within limits first.
Often, as the main rotor became smoother and below 0.1 IPS, it often made the 4 per rev vibes much more noticeable to the point of thinking that the machine is actually getting rougher.. This link may help
https://www.rwas.com.au/rotor-track-and-balance-rtb/
Scroll down to "Nper Rev Vibration"
Also if the blades are getting some time up on them and depending on their service history, be cautious if the move lines begin to move tangentially rather than close to parallel to expected move lines i.e. if the move line doesn't track toward the zero origin but moves tangentially past the origin and the minimum achievable vibe level is still excessive (>0.2/0.25ips) It may indicate a span moment mis-match which may need the blades to be statically balanced and tip weights adjusted. to bring the span moment back within limits.
See this link for explaination:
https://www.rwas.com.au/the-blade-problem/
I will PM you a guide on how to create you own polar chart if all else fails....
cheers
RG
