R44 ground handling
I was at a local airport the other day, visiting an avionics shop and I watched a mechanic at an adjacent hangar, moving an R44 into the hangar.
In order to put the rotor blades fore and aft, he rotated the tail rotor by hand. Is that a permitted practice? |
It’s normal practice.
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Yes, normal. I like to do it by the hub, though. No point in putting stress on the actual tail rotor blades.
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Originally Posted by India Four Two
(Post 10805137)
I was at a local airport the other day, visiting an avionics shop and I watched a mechanic at an adjacent hangar, moving an R44 into the hangar.
In order to put the rotor blades fore and aft, he rotated the tail rotor by hand. Is that a permitted practice? ,...primarily due to "safety tip 14" where it states that, "Stopping or rotating the tail rotor by hand can damage the tail rotor drive" It seems like such an obscure place to put that? If it were a true "caution don't do this" I would image they'd put it somewhere more "out in the open", but I always forget to ask when I'm at RHC,...and I was just there in February!,...ha! |
In what document and page is this safety tip?
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Originally Posted by aa777888
(Post 10805244)
In what document and page is this safety tip?
,...but its also in my R22 book as well. |
If you are referring to Safety Tip 14 in the current R44 II POH, that's not relevant. Apples and oranges. Gently repositioning blades that are already stopped using the tail rotor is acceptable. Trying to use the tail rotor as a rotor brake is not.
"14. Do not use collective pitch to slow the rotor during shut-down. Collective pitch produces lift on the blades which can disengage the droop stop friction and allow the blades to strike the tailcone. Also, do not slow or stop the rotors by grabbing the tail rotor. Stopping the tail rotor by hand can damaged the tail rotor drive." |
if the helicopter I was on was so fragile in the drivetrain, that rotating the TR by hand was a risk to damage it, then i would rethink flying it.
now taking into consideration that there are many hamfisted individuals out there...i can see why the cautions are there. |
Spinning the Blades
“Stopping or rotating the tail rotor by hand can damage the tail rotor drive”.
Is possibly referring to the practice of spinning the blades in cold weather prior to engine start, I would carry an 18in folding step allowing me to remove the front blade tie-down, spin the blade to take off the rear tie-down then continue spinning 4 more revolutions to listen to the gearbox and drive. This was standard procedure on a Gazelle which didn’t require an 18in Step. |
Originally Posted by aa777888
(Post 10805665)
If you are referring to Safety Tip 14 in the current R44 II POH, that's not relevant. Apples and oranges. Gently repositioning blades that are already stopped using the tail rotor is acceptable. Trying to use the tail rotor as a rotor brake is not.
"14. Do not use collective pitch to slow the rotor during shut-down. Collective pitch produces lift on the blades which can disengage the droop stop friction and allow the blades to strike the tailcone. Also, do not slow or stop the rotors by grabbing the tail rotor. Stopping the tail rotor by hand can damaged the tail rotor drive." They change this thing so much, its hard to keep up. :( |
Regularly turn the blades by rotating the TR during pre-flight. Never standing outside it when the blades are moving after shut down.
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Originally Posted by Hilico
(Post 10805919)
Regularly turn the blades by rotating the TR during pre-flight. Never standing outside it when the blades are moving after shut down.
Not turning the tail rotor by hand (like say during preflight) is what always had me wondering,...why? Maybe it was just a typo in the old books? |
Not sure there's any other way to check the tail rotor flex coupling than by turning the tail rotor blades and looking through the sight glass.
aa777888, interesting point. I wonder what the stresses are on the blades in flight? Longitudinally, I'd guess they're enormous, laterally, they'll be huge. But lead/lag, wonder where they fit in? |
I think it is just that the piddly gears in the T/R box are designed for stresses in only one way. Sudden stoppage or a rapid change in direction by hand could cause some problems. Be gentle.
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Originally Posted by India Four Two
(Post 10805137)
I was at a local airport the other day, visiting an avionics shop and I watched a mechanic at an adjacent hangar, moving an R44 into the hangar.
In order to put the rotor blades fore and aft, he rotated the tail rotor by hand. Is that a permitted practice? |
to put things in context: machine force against human force
The tail rotor system is likely absorbing 10% of your total power at times, let say up to 20Kw, with wide variations of torque on pedal input. A bicycle rider can produce 100W to 300W |
Originally Posted by Robbo Jock
(Post 10806098)
Not sure there's any other way to check the tail rotor flex coupling than by turning the tail rotor blades and looking through the sight glass.
aa777888, interesting point. I wonder what the stresses are on the blades in flight? Longitudinally, I'd guess they're enormous, laterally, they'll be huge. But lead/lag, wonder where they fit in? |
aa: if you really want to awaken your OCD, think about the loads on the tail rotor gearbox when you rotate the tail rotor in the "right" direction. They are actually opposite the normal.
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Actually they're exactly the same as the load from autorotation.
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Ha ha, true! :} I guess I better rotate it the other way from now on!
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