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?

FOD

Well spotted, that may have saved somebody's life - even yours.

G

You have any foto?

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:E

a) meteorite

b) the butler did it

c) small children on stepladder with sticks

d) any one of your enemies

e) any one of your friends

f) the al-quaida neighbors

Sounds like hangar rash to me, a photo would be very helpful!

Are -4 blades one's that have to be replaced anyway?

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 hanger rash.

FOD on the trailing edge??

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:(

extremely extremely high coning angle...?
Check the other blade!

:}

Lu did it!!!!!!

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.


:E :E

.. 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.

Is this the machine that the blade hit the tail under the influence of Gazelle downwash??

Just wondering.

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

Picture of kinky blade, as requested;

http://www.unicopter.com/Temporary/gayblade.jpg

:O

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.