The venerable Bell 47
Join Date: Feb 2005
Location: Australia
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To me it looks like less than 2 man days of work.
A 100 hrly will take at least two man days on a '47 machine that has absolutely no problems.
If it was an initial into country C of A inspection then in OZ that would be at least $6000.00
You may have done very well.
tet
How long is a piece of string?
Couple of questions.................
What was the experience level of the person who put it back together?
Helicopters in total?
On the type? - They are getting a bit "rare" these days.
And how recently? See above.
Do you think 70 hours is excessive? The helicopter would still have to have been released as serviceable, not just "put back together" otherwise you would have done it yourself.
More info would be a help.
With regard to your "maintenance release" if you read the regulations, as the aircraft was effectively disassembled and shipped somewhere. It may no longer be in force.
Read Reg 47 from a CASA viewpoint!
Couple of questions.................
What was the experience level of the person who put it back together?
Helicopters in total?
On the type? - They are getting a bit "rare" these days.
And how recently? See above.
Do you think 70 hours is excessive? The helicopter would still have to have been released as serviceable, not just "put back together" otherwise you would have done it yourself.
More info would be a help.
With regard to your "maintenance release" if you read the regulations, as the aircraft was effectively disassembled and shipped somewhere. It may no longer be in force.
Read Reg 47 from a CASA viewpoint!
Last edited by RVDT; 3rd Jun 2008 at 05:49.
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So you've had the 47 put back together and are now moaning about a lack of useful answers in relation to costs?
BTW Removal of blades, head, mast, skids etc is hardly what I'd call 'slightly disassembled'
BTW Removal of blades, head, mast, skids etc is hardly what I'd call 'slightly disassembled'
Join Date: Jun 2005
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Join Date: Sep 2007
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Yes we have one at our school. Based in Chester area, about to be features in Todays Pilot magazine! PM for details(cos I work there and dont want to get in trouble for advertising!!)
Join Date: Sep 2007
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Wiling to Swap an hour plus or so in my 47 for some time in something different, to get it on my log book...open to offers. Can sort out FE for the 47 if required in return...
Kevin.
Kevin.
Join Date: Apr 2004
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I started my 47 today in colder conditions than I usually do and the clutch woudnt accelerate the blades much over 60-100rpm (guess).
I didnt try dropping the throttle to let it fully engage as i thought the blades were turning too slow to allow the engine to keep going with clutch engaged.
I did try increasing the engine rpm higher than normal just to try get the blades going faster but no noticeable effect.
I stopped the engine and tried again and it engaged the rotor normally and I had a perfectly normal flight.
Should I be worried? I know some operators who warm their 47 with a propane burner on a cold morning but I thought that was purely for warming the engine. Can the clutch become lazy with cold temperatures?
OOW
I didnt try dropping the throttle to let it fully engage as i thought the blades were turning too slow to allow the engine to keep going with clutch engaged.
I did try increasing the engine rpm higher than normal just to try get the blades going faster but no noticeable effect.
I stopped the engine and tried again and it engaged the rotor normally and I had a perfectly normal flight.
Should I be worried? I know some operators who warm their 47 with a propane burner on a cold morning but I thought that was purely for warming the engine. Can the clutch become lazy with cold temperatures?
OOW
Join Date: Dec 2001
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I've often had to stop the engine & then restart, worked every time. I expect the clutch is getting a bit shiny, so I wouldn't be keen to ignore it for too long.
Join Date: Apr 2004
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Thx Nigel,
This is the first time I have noticed this happen and nobody else has flown her in the last 100 tacho hours.
From your experience - can I expect this every time I start from now on or does it come and go (and hence take a while for the clutch to get worse).
I was hoping to take her on a long trip soon! Probably 20 flight hours, 10 starts.
OOW
This is the first time I have noticed this happen and nobody else has flown her in the last 100 tacho hours.
From your experience - can I expect this every time I start from now on or does it come and go (and hence take a while for the clutch to get worse).
I was hoping to take her on a long trip soon! Probably 20 flight hours, 10 starts.
OOW
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I had this happen in a 47J in Tassie in mid winter, snow, ice, etc. The engineer deglazed the clutch after 1 week. In PNG & Darwin this happened in a 3B1 & in a G2 in Sydney; I can't remember how long we put up with it as it does get worse, probably 2 weeks at the most. I think it is caused by poor engagement technique such as incorrect throttle control. It doesn't take that long, winching up the trannie gives you access to the clutch.
I wouldn't like to suggest what you do as all this happened so long ago!
Send me a private msg if you like.
I wouldn't like to suggest what you do as all this happened so long ago!
Send me a private msg if you like.
Bell 47 TRE
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OOW
I'd like to suggest that when you lift the xmon that you also pull the freewheel and check it. The symptoms you descirbe fit perfectly to a freewheel failure soon.
How long since the xmon has been overhauled or a mid point (600hrly) done. One thing for sure is that if you cannot vouch for the exact hours then you should check it. The non negotiable exact time called up inspections are for the grips and freewheel on any '47.
see if it is a lighweight or medium weight freewheel. if it is either try to get a heavyweight unit installed.
you may be able to check the worksheet of the last xmon overhaul, to see if new rollers were installed or at least the actual miked measurements of the rollers and ring.
when the freewheel fails the engine goes straight to valve bounce speed, if you are lucky the fan and or fan belts don't take out any of the flight controls and you descend immediately. it is a (VERY) frightening and disorientating sound.
But as Nigel says it may just be the clutch which could be because of a loose retaining nut, which means check it straight away afore you wreck your fan drive.
tet
I'd like to suggest that when you lift the xmon that you also pull the freewheel and check it. The symptoms you descirbe fit perfectly to a freewheel failure soon.
How long since the xmon has been overhauled or a mid point (600hrly) done. One thing for sure is that if you cannot vouch for the exact hours then you should check it. The non negotiable exact time called up inspections are for the grips and freewheel on any '47.
see if it is a lighweight or medium weight freewheel. if it is either try to get a heavyweight unit installed.
you may be able to check the worksheet of the last xmon overhaul, to see if new rollers were installed or at least the actual miked measurements of the rollers and ring.
when the freewheel fails the engine goes straight to valve bounce speed, if you are lucky the fan and or fan belts don't take out any of the flight controls and you descend immediately. it is a (VERY) frightening and disorientating sound.
But as Nigel says it may just be the clutch which could be because of a loose retaining nut, which means check it straight away afore you wreck your fan drive.
tet
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Outofwhack,
I remember the first time it happened to me, very disconcerting, but in my case I was a long way from anywhere in the Canadian bush. Word from engineering was "anytime it happens, shut the engine down straight away, go inside and have a cup of coffee, wait about 10 minutes and try again".
The clutch always engaged normally second time around.
I'm going back to the 70's here so can't remember the exact conditions at which these things were done. This company had operated several 47s of different marks for fifteen years at that point, winter and summer, and had some very experienced guys maintaining them. I was around 47s for three years and never heard of any safety concern with this phenomenon nor can I recall any clutch problems which may have come because of it.
Also, for your info, below a certain temperature on moist days, on the first start of the day, we pulled one set of plugs [left or right, didn't matter] and put them in the oven to warm them. It made starting much easier as icing of the plugs was an occasional problem as well.
I remember the first time it happened to me, very disconcerting, but in my case I was a long way from anywhere in the Canadian bush. Word from engineering was "anytime it happens, shut the engine down straight away, go inside and have a cup of coffee, wait about 10 minutes and try again".
The clutch always engaged normally second time around.
I'm going back to the 70's here so can't remember the exact conditions at which these things were done. This company had operated several 47s of different marks for fifteen years at that point, winter and summer, and had some very experienced guys maintaining them. I was around 47s for three years and never heard of any safety concern with this phenomenon nor can I recall any clutch problems which may have come because of it.
Also, for your info, below a certain temperature on moist days, on the first start of the day, we pulled one set of plugs [left or right, didn't matter] and put them in the oven to warm them. It made starting much easier as icing of the plugs was an occasional problem as well.
