Robinson R44
Join Date: Nov 2005
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R44 clipper track and balancing
Has anyone experienced their R44 Clipper ( pop out equipped ) go through periods of smooth to buppy flight (vertical bounce) this is the second clipper I have had experienced with and they both seem to change considerably with weight, if the ship is tracked at a certain weight it seems to be way out at the opposite weight. From what others say it seems to be the floats as the only cause. Any thoughts?
Join Date: Apr 2002
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Most Raven IIs have an 80 kt flutter....it can be tuned out to beyond your speed range on a clipper. Ask your maint people to do a track and balance and shift the vibration up to 120kts. A clipper never sees that speed.
Join Date: Mar 2002
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Gaseous
No it has not been re sprayed and from what I can see it is only the top layer of the paint that's bubbling. Yeah I don't think I'll get much joy from Robinson but I'll try.
The 80 Kt fluffer, well we have had this on our Raven I since new, despite numerous track n balance. It gets worse when heavy...
Cheers
No it has not been re sprayed and from what I can see it is only the top layer of the paint that's bubbling. Yeah I don't think I'll get much joy from Robinson but I'll try.
The 80 Kt fluffer, well we have had this on our Raven I since new, despite numerous track n balance. It gets worse when heavy...
Cheers
Passion Flying Hobby Science Sponsor Work
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Max speed versus Weight R44
A while ago, I stumbled over a weird condition/prediction of my R44-simulator.
When very light (f.ex. little fuel, 1POB), it takes more power to achieve high speeds.
Could be an error, but I can't seem to find it, so I tried to explain it.
I came up with the following possible explanation:
At light weight the trust vector is smaller. To achieve a speed, the drag forces are relatively unsensitive to weight, resulting in essentially the same needed forward force to achieve a speed.
In the case of light weight, and the resulting lower trust vector this requires the rotor disk to be tillted more forward than when heavy. At some point the forward tilt gets so great that it reduces rotor efficiency because transversal flow increases too much, requiring a lot of power to achieve this smaller trust. The rotary wing becomes an inefficient propeller so to speak.
I tried this out on a R44-I and II, and feel that with 2 POB, little fuel it is indeed faster than with 1 POB. Anyone care to comment ?
d3
When very light (f.ex. little fuel, 1POB), it takes more power to achieve high speeds.
Could be an error, but I can't seem to find it, so I tried to explain it.
I came up with the following possible explanation:
At light weight the trust vector is smaller. To achieve a speed, the drag forces are relatively unsensitive to weight, resulting in essentially the same needed forward force to achieve a speed.
In the case of light weight, and the resulting lower trust vector this requires the rotor disk to be tillted more forward than when heavy. At some point the forward tilt gets so great that it reduces rotor efficiency because transversal flow increases too much, requiring a lot of power to achieve this smaller trust. The rotary wing becomes an inefficient propeller so to speak.
I tried this out on a R44-I and II, and feel that with 2 POB, little fuel it is indeed faster than with 1 POB. Anyone care to comment ?
d3
Join Date: Dec 2004
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Doesn't Induced Lift and Drag change with weight???
The induced drag curve moves to the right with increase weight and left with reduced weight. Parasite and Profile drag donīt change much in relation to weight. This will effect the Overall Power required curve, this will mean more power is requied for less weight at the same speed.........
The induced drag curve moves to the right with increase weight and left with reduced weight. Parasite and Profile drag donīt change much in relation to weight. This will effect the Overall Power required curve, this will mean more power is requied for less weight at the same speed.........
Join Date: Jan 2002
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WLM
What you have described is a Chordwise mass discrepancy on your main rotor.
The twist of the blades as a function of power (blade coning) is controlled by chordwise mounted tip weights (tracking weights) if they are at odds you can only tune the rotor to be good for a narrow AUM range using pitch link and tab corrections.
If you want to cure it you may have to get the blades reweighed and checked for spanwise and especially chordwise CofG , there will be a tolerance on the figures and I suspect you will have two blades on opposite ends of the tolerance. Has one of your blades been repaired I wonder?
Here's a post I did earlier describing how the effect is used to control the track and vibes on a Bell 412
http://www.pprune.org/forums/showthr...19#post1560419
Cheers
W
What you have described is a Chordwise mass discrepancy on your main rotor.
The twist of the blades as a function of power (blade coning) is controlled by chordwise mounted tip weights (tracking weights) if they are at odds you can only tune the rotor to be good for a narrow AUM range using pitch link and tab corrections.
If you want to cure it you may have to get the blades reweighed and checked for spanwise and especially chordwise CofG , there will be a tolerance on the figures and I suspect you will have two blades on opposite ends of the tolerance. Has one of your blades been repaired I wonder?
Here's a post I did earlier describing how the effect is used to control the track and vibes on a Bell 412
http://www.pprune.org/forums/showthr...19#post1560419
Cheers
W
Join Date: Jul 2005
Location: australia
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Hooks for r44
Our company is looking at getting rid of our old hooks on our r44's for the latest and greatest on the market.
Any bad stories with with equipment or any recommendations would be much appreciated.
We've heard all the hype about Onboard systems so they must have a good product but outlaying for a few r44's adds up so all feedback adds up
cheers tropic
Any bad stories with with equipment or any recommendations would be much appreciated.
We've heard all the hype about Onboard systems so they must have a good product but outlaying for a few r44's adds up so all feedback adds up
cheers tropic
Join Date: Mar 2002
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Wunper: Thanks for the info. I posted 2 days ago but for some reason it is showing up. Anyway will show your info to our engineers
R44Tropic: I asked the same question about 5 weeks ago but did not get any reply
may be it is not a popular aircraft type to sling with in the Northern Hemisphere.... Let see what happens this time around
WLM
Oops typo error...meant to say posting did not show up
R44Tropic: I asked the same question about 5 weeks ago but did not get any reply
may be it is not a popular aircraft type to sling with in the Northern Hemisphere.... Let see what happens this time aroundWLM
Oops typo error...meant to say posting did not show up
Join Date: Jul 2005
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wlm cheers.
mate we have regular sling jobs here. we're actually prefered to our opposition cause they're using jetrangers.
Our clients would rather take a couple of trips slinging gear than using them mainly due to our personel with much smaller ego's
tropic
mate we have regular sling jobs here. we're actually prefered to our opposition cause they're using jetrangers.
Our clients would rather take a couple of trips slinging gear than using them mainly due to our personel with much smaller ego's
tropic
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Gday mate
Now what sort of hook system you're using at the moment? any mirror installation on the R44 or just head out? What can you comfortably lift?
I did my sling endorsement in a B47 then slinged with the Jety but I don't have the big ego..... Been flying a R44 Raven for the last 2 years in the jungle, and need to reposition 44 gallons drums so I thought a hook and 1 drum at a time for short distance would be ok? 2 would be pushing it
Also the NZ company selling the R44 pods seemed to have a hook rep contact, but I'm still waiting
Cheers
WLM
Now what sort of hook system you're using at the moment? any mirror installation on the R44 or just head out? What can you comfortably lift?
I did my sling endorsement in a B47 then slinged with the Jety but I don't have the big ego..... Been flying a R44 Raven for the last 2 years in the jungle, and need to reposition 44 gallons drums so I thought a hook and 1 drum at a time for short distance would be ok? 2 would be pushing it
Also the NZ company selling the R44 pods seemed to have a hook rep contact, but I'm still waiting
Cheers
WLM
Better red than ...
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R44 Rotor Vibration
The poor CFI got a shock this morning with sudden significant vibration from the rotor head.
The description of the event is:-
Start and airtaxi, nothing out of the ordinary.
Significant vibration starts in the climb, occured intermittent downwind and to land. Continues in air taxi back to the stand.
Vibration felt throughout the aircraft but INTERMITTENT, and tending to occur during pitch changes (hence more during air taxi).
Described as "like flying in high wind condition" but wind was under 5kts.
Examiner who flew it last, describes slight mis tracking on the main blades.
Engineer has a view on potential cause.
Aircraft had annual 7hrs ago. No known defects and nothing obvious (or not obvious) in a visual and 'manual' inspection after the incident. No leaks, cracks in the blade, dents, loose transmission parts, tail rotor still attached.
H-R interested to hear if other people have experienced rotor head vibration in a 44 and the cause.
Discuss
h-r
(who has turned blue at the chill of the cost..)
The description of the event is:-
Start and airtaxi, nothing out of the ordinary.
Significant vibration starts in the climb, occured intermittent downwind and to land. Continues in air taxi back to the stand.
Vibration felt throughout the aircraft but INTERMITTENT, and tending to occur during pitch changes (hence more during air taxi).
Described as "like flying in high wind condition" but wind was under 5kts.
Examiner who flew it last, describes slight mis tracking on the main blades.
Engineer has a view on potential cause.
Aircraft had annual 7hrs ago. No known defects and nothing obvious (or not obvious) in a visual and 'manual' inspection after the incident. No leaks, cracks in the blade, dents, loose transmission parts, tail rotor still attached.
H-R interested to hear if other people have experienced rotor head vibration in a 44 and the cause.
Discuss
h-r
(who has turned blue at the chill of the cost..)
Last edited by helicopter-redeye; 30th Nov 2005 at 16:56.
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Re: R44 Rotor Vibration
Originally Posted by helicopter-redeye
The poor CFI got a shock this morning with sudden significant vibration from the rotor head.
The description of the event is:-
Start and airtaxi, nothing out of the ordinary.
Significant vibration starts in the climb, occured intermittent downwind and to land. Continues in air taxi back to the stand.
Vibration felt throughout the aircraft but INTERMITTENT, and tending to occur during pitch changes (hence more during air taxi).
Described as "like flying in high wind condition" but wind was under 5kts.
Examiner who flew it last, describes slight mis tracking on the main blades.
Engineer has a view on potential cause.
Aircraft had annual 7hrs ago. No known defects and nothing obvious (or not obvious) in a visual and 'manual' inspection after the incident. No leaks, cracks in the blade, dents, loose transmission parts, tail rotor still attached.
H-R interested to hear if other people have experienced rotor head vibration in a 44 and the cause.
Discuss
h-r (who has turned blue at the chill of the cost..)
The description of the event is:-
Start and airtaxi, nothing out of the ordinary.
Significant vibration starts in the climb, occured intermittent downwind and to land. Continues in air taxi back to the stand.
Vibration felt throughout the aircraft but INTERMITTENT, and tending to occur during pitch changes (hence more during air taxi).
Described as "like flying in high wind condition" but wind was under 5kts.
Examiner who flew it last, describes slight mis tracking on the main blades.
Engineer has a view on potential cause.
Aircraft had annual 7hrs ago. No known defects and nothing obvious (or not obvious) in a visual and 'manual' inspection after the incident. No leaks, cracks in the blade, dents, loose transmission parts, tail rotor still attached.
H-R interested to hear if other people have experienced rotor head vibration in a 44 and the cause.
Discuss
h-r
(who has turned blue at the chill of the cost..)Last edited by Flingwing207; 16th Jan 2006 at 03:05.
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Re: R44 Corner
R44 Airconditioning
Can anyone tell me how the Aircond. 44's perform. I wonder if the compressor cuts out under max power, that sort of thing and most importantly dose the air con work good.
Can anyone tell me how the Aircond. 44's perform. I wonder if the compressor cuts out under max power, that sort of thing and most importantly dose the air con work good.
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Re: R44 Corner
Redeye and 207.
If I was flying any Robinson that developed sudden rotor vibration I would be on the ground FAST. Have a read of the report...http://www.atsb.gov.au/publications/...200302820.aspx
If I was flying any Robinson that developed sudden rotor vibration I would be on the ground FAST. Have a read of the report...http://www.atsb.gov.au/publications/...200302820.aspx
Better red than ...
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Re: R44 Corner
Overpitched.
The person flying was on the ground rather quick.
Was checked by certified engineers (note plural). Head de-ass. Blades off and checked; MR and TR tracked and balanced; hydraulics taken apart.
Nothing found.
May have been some ice build up as it was a cold day and early morning, but like all icematters, now we shall never know ..
The person flying was on the ground rather quick.
Was checked by certified engineers (note plural). Head de-ass. Blades off and checked; MR and TR tracked and balanced; hydraulics taken apart.
Nothing found.
May have been some ice build up as it was a cold day and early morning, but like all icematters, now we shall never know ..
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Re: R44 Corner
HR. I experienced such a vibration in an R44 some time ago. The cause was worn out teeter bearings. The journals that fit into the teflon couted bearings were also damaged since the journals grinded it way into the hub itself 
Unfortunately I was not flying this particular bird enough to catch the wear early on the bearings. I believe the bearings have since been changed by Robinson because this was a common problem from operators that are pulling lots of torque when slinging. Go to your helicopter and carefully inspect the teeter bolt trust washers. If there is any bearing material missing between the hub and the truet washers your M/R Hub need to have it's bearings changed including the journals....
Good luck
Unfortunately I was not flying this particular bird enough to catch the wear early on the bearings. I believe the bearings have since been changed by Robinson because this was a common problem from operators that are pulling lots of torque when slinging. Go to your helicopter and carefully inspect the teeter bolt trust washers. If there is any bearing material missing between the hub and the truet washers your M/R Hub need to have it's bearings changed including the journals....Good luck
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Re: R44 Corner
Hi Flingwing,
I am an owner/ operator of a new Raven 2.
What damage is done in a rotor overspeed? What sort of cost is involved in putting it right?
Is the R44 designed to withstand the occasional mismanagement of the controls eg not being quick enough on the collective in the auto or mishandling the throttle?
My machine is not used for training or hire but I do expect to let others fly it occasionaly, hence the question. If the risks of accident/ high rectification costs are too great I'l keep it all to myself!
Hairyplane
I am an owner/ operator of a new Raven 2.
What damage is done in a rotor overspeed? What sort of cost is involved in putting it right?
Is the R44 designed to withstand the occasional mismanagement of the controls eg not being quick enough on the collective in the auto or mishandling the throttle?
My machine is not used for training or hire but I do expect to let others fly it occasionaly, hence the question. If the risks of accident/ high rectification costs are too great I'l keep it all to myself!
Hairyplane