Kinked rotor blade
Thread Starter
Joined: Feb 2002
Posts: 176
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From: england
Kinked rotor blade
Robinson r22 dash 4 stainless type blades
I have found a very small kink on the trailing edge 5ft from the hub. No idea how this has happened.
Machine six months old, 205 hours TTSN, Never left outside in windy conditions.
No heavy landings
The kink is on the top of the blade and looks like its been hit with a piece of timber on edge.
Any ideas how this has happened?
I have found a very small kink on the trailing edge 5ft from the hub. No idea how this has happened.
Machine six months old, 205 hours TTSN, Never left outside in windy conditions.
No heavy landings
The kink is on the top of the blade and looks like its been hit with a piece of timber on edge.
Any ideas how this has happened?
Joined: Aug 2000
Posts: 3,670
Likes: 1
From: UK
You asked for this
Don't blame us, we were all busy on this forum writing helpful ditties. We couldn't have been in the hangar when that happened..honest.
How the hell do we know, we dont live with you???
is it stored in a garage, barn? Do owls live there too?
Was it hit by your kids radio controlled aeroplane/
Did someone spin the blades for a laugh and then stop it by probing it with a broom handle??/
How do we know???
Hope its useful
Don't blame us, we were all busy on this forum writing helpful ditties. We couldn't have been in the hangar when that happened..honest.
How the hell do we know, we dont live with you???
is it stored in a garage, barn? Do owls live there too?
Was it hit by your kids radio controlled aeroplane/
Did someone spin the blades for a laugh and then stop it by probing it with a broom handle??/
How do we know???
Hope its useful
Thread Starter
Joined: Feb 2002
Posts: 176
Likes: 0
From: england
Dash 4 blades are the latest blades out. photo to follow.
High coning angles, Engine off in the hover allowing the rpm to drop to say 75% for couple of secs coluld that kink the blade.
Definately not hangar rash.
FOD on the trailing edge??
High coning angles, Engine off in the hover allowing the rpm to drop to say 75% for couple of secs coluld that kink the blade.
Definately not hangar rash.
FOD on the trailing edge??
Senis Semper Fidelis
Joined: Feb 2001
Posts: 1,288
Likes: 0
From: Lancashire U K
1. Bird ( now dead)
2. Irrate husband/boyfriend of some gal you know too well
3. Irrate wife! or some gal who would like to be!
4. really teeed off father of some gal.
But whatever and however, dont fly untill replaced!
Peter RB
Vfr
2. Irrate husband/boyfriend of some gal you know too well
3. Irrate wife! or some gal who would like to be!
4. really teeed off father of some gal.
But whatever and however, dont fly untill replaced!
Peter RB
Vfr
Iconoclast
Joined: Sep 2000
Posts: 2,132
Likes: 0
From: The home of Dudley Dooright-Where the lead dog is the only one that gets a change of scenery.
High coning angle? The POH warns against this.
To: cyclic flare
Since everyone else is hazarding a guess or trying to be funny I’ll hazard a guess. If the blades had a high coning angle and you introduced any cyclic input the blades would be exposed to high lead lag loads. This could overstress the blades along the spanwise axis resulting in metal deformation. In this case, the blades would have to flap in relation to the underslung rotorhead.
Not a single word about the 18-degree offset.
And no, I didn’t do it.
Since everyone else is hazarding a guess or trying to be funny I’ll hazard a guess. If the blades had a high coning angle and you introduced any cyclic input the blades would be exposed to high lead lag loads. This could overstress the blades along the spanwise axis resulting in metal deformation. In this case, the blades would have to flap in relation to the underslung rotorhead.
Not a single word about the 18-degree offset.
And no, I didn’t do it.
Joined: Jul 2000
Posts: 733
Likes: 0
From: The Daylight Saving Free Zone
.. or perhaps a crap pilot!
Going by all the circumstantial evidence given, including eyewitness reports, I can only conclude that ..... its been hit with a piece of timber on edge ... or high coning angles, with the engine off in the hover allowing the rpm to drop to say 75% for couple of secs.
Seriously, it would be good to see those pics.
Going by all the circumstantial evidence given, including eyewitness reports, I can only conclude that ..... its been hit with a piece of timber on edge ... or high coning angles, with the engine off in the hover allowing the rpm to drop to say 75% for couple of secs.
Seriously, it would be good to see those pics.
Thread Starter
Joined: Feb 2002
Posts: 176
Likes: 0
From: england
The kink is normal.
Following further inspection if you look a the trailing edge there is a difference / change in thickness of the trailing edge. From approx 2.5mm - 2mm which appears as a kink.
RHC response
Without actually examining the blade we cannot confirm airworthiness. Having said that, there are some blade characteristics you should be aware of:
At R.S. 64.00 + or - 0.5 two pieces of honeycomb adjoin, maximum allowable external bulge at this location is 0.020inch.
Also at 64.00 one 0.6 inch wide trailing edge internal (Between blade skins) doubler ends
At R.S. 61.90 + or - 1.00 there is a thread rap around the internal trailing edge doublers which typically produces a barely detectable 0.6 inch chordwise bulge at the trailing edge.
An allowable "washboard effect" consisting of chordwise depressions of 0.010 inch maximum depth may be found along the entire span approx every 1.5 inches. Such depressions may extend chordwise from the aft face of the leading edge D spar to just forward of the trailing edge bond joint
Following further inspection if you look a the trailing edge there is a difference / change in thickness of the trailing edge. From approx 2.5mm - 2mm which appears as a kink.
RHC response
Without actually examining the blade we cannot confirm airworthiness. Having said that, there are some blade characteristics you should be aware of:
At R.S. 64.00 + or - 0.5 two pieces of honeycomb adjoin, maximum allowable external bulge at this location is 0.020inch.
Also at 64.00 one 0.6 inch wide trailing edge internal (Between blade skins) doubler ends
At R.S. 61.90 + or - 1.00 there is a thread rap around the internal trailing edge doublers which typically produces a barely detectable 0.6 inch chordwise bulge at the trailing edge.
An allowable "washboard effect" consisting of chordwise depressions of 0.010 inch maximum depth may be found along the entire span approx every 1.5 inches. Such depressions may extend chordwise from the aft face of the leading edge D spar to just forward of the trailing edge bond joint
Joined: Oct 2004
Posts: 16
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From: UK
Kinked rotor blade
A bit more info reqrd. Initial post by cyclic flare asking how dent or ding might occur. Later post by cyclic flare asking if engine out in hover resulting in low rotor rpm could do it. Are we to assume that this machine has in fact been subjected to a low rotor rpm situation whilst in hover, and if this was the case was the subsequent landing normal or heavy. Is the opposite blade free from defects in the same area as the alleged damaged blade. Is there something more that we need to know in order to give a reasonably accurate answer.
