Oh, we're into strong stories now, eh?

In Northern Iceland, in the Krafla region, a magma chamber sits relatively close to the surface. This boils the ground water, and since that water has no way to escape, the pressure builds up. The Icelandic people drill holes in the ground and tap into these high pressure steam chambers to run turbines to produce electricity.

One such drill action went spectacularly wrong, and led to the steam chamber exploding. Bits of the drill were apparently found three kilometers away. Fortunately nobody was hurt.

Krafla - Lonely Planet

I had a mate on a drilling rig that the driller made a slight cockup with his mud weights.

This led to a 800m string of drill pipe getting blown out the drill hole and the BOP didn't fire. It went straight up through the Derrek.

Then another one that was stall testing a tunnelling unit gear box when the wrong end of it became untethered and the whole bloody engine started rotating. He only managed to stop it by taking an axe to the fuel line which was of fire hose diameter.

To be honest I think all of us survived our 20's more by luck than skill or common sense.

A diving buddy witnessed what happens when you drop a filled air tank (230 bar) and the fall breaks off the valve on the end. The whole air tank went straight thru a concrete wall 1 meter thick and ended up sticking in the next wall on the other side of the room.

And we strap these things to our back willingly :}

Truer words have rarely been spoken!

Oxygen tanks on a trolley , greasy fingers, hangar deck Ark Royal all aircraft fully loaded ready for flight next morning. Total mayhem, then some pillock lowered the fire curtain between us fire crew & the fire.
I'd like to have seen 800m of drill going through the Derrick though!

I have a pic of the prop stump, anyone know how i can post it on here?

you have to find somewhere that will host it and then get the link out of it.

Either that or upload it into dropbox and post the link of that.

It won't be viewable with dropbox but we will get it full sized without it screwing with the forum.

https://onedrive.live.com/redir?resi...nt=photo%2cJPG

https://onedrive.live.com/redir?resi...nt=photo%2cJPG

Let me know if you can see this

or maybe this link below
https://onedrive.live.com/redir?resi...nt=photo%2cJPG

https://onedrive.live.com/redir?resi...nt=photo%2cJPG

that site doesn't support sharing of photo's.

BUt I got to see it from the bad link properties.

For the engineers among us can you try and get a photo of the flat fracture face please like the picture by Nonsense post as an example.

Does look like a fatigue fracture followed by fast fracture.

It still has not been found so it must have traveled outside the field boundary as the area directly to the left and right of the planes position when it came of his heavily trafficked.

I would go and have a look in Venice reservoir site.

Some one would have found it by now if it had gone into housing.

But if it speared in it may well be under ground.

What are the chances of oscillation on a prop blade?

loads which is why commercial operators get them dynamically balanced every so often.

And when something changes you know about it as a pilot you can feel it through your backside and your feet on the rudder pedals.

https://oijb2g.by3302.livefilestore....6/IMG_1201.JPG

Hopefully you can all see the image above.

yes but its utterly useless.

We need to see the fracture face perpendicular.

it looks very spectacular which it is but we can see sod all apart from the fast fracture failure and nothing about the fatigue surface.

:eek: How far out from the spinner was the fracture?


MJ:ok:

A shot of the whole blade section would be more interesting, those black marks on the near top left hand side might be the start of something.

As Jock says, it's hard to determine the cause for sure from the pic, but it looks like it may, unusually, have started from the trailing edge of the blade, and have been started off by some damage to the rear face of the blade, near the trailing edge.

We all check the leading edge of blades for chips, but perhaps we don't pay as much attention to the rear face of the blade as we should?


MJ:ok:

.
Sherlock Holmes here.... Look at the shadow on the cowling. It looks as if the break was 6-8 inches from the hub root.


I did a Parabolic calculation for a perfect projectile, and the range was about 6.3 km in 36 seconds (starting at 250m/s at 45deg.). However this blade would have been spinning and tumbling, so the variable aerodynamic forces would severely reduce the range. If during one of its tumbles, it went leading edge first, then the lift created by its 'wing section' would dramatically change the direction of the trajectory.


Use the Peak Height, Range and Time of Flight Calculator at....
Trajectories


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