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Aircraft fighting NSW bushfire crashes


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Guest pookemon

The ABC said it was an air tractor, however the above links both say it's an M-18 Dromader. It doesn't sound good - hopefully it isn't something that will ground the other water bombers.

 

 

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Yes, well, agricultural aircraft can operate at whatever weight the pilot considers he can get off the ground. Add this to a cantilever wing, and you have a formula for wing fatigue failure. See http://www.ruudleeuw.com/tanker130.htm

Actually not. The formula for fatigue is miners rule... check the other axis of the curve...

 

 

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Wing loss in water bombing aircraft is not uncommon. Some of the turbulence they encounter must be quite violent. Could be simply overload in those circumstances. Fatigue reduces life and /or causes cracks, intergranular corrosion etc Cantilever wings are a difficult structure.( For me anyhow). I can analyse the sheer and bending etc, but how does it stand up in service? Fatigue test? How often are they done? I saw the Mirage wing at Fishermen's Bend. Apparently Dassault hadn't done one to the extent that was done as we kept them is service for a long time. Nev

 

 

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i was thinking along similar lines, how many pilots actually observe the turbulence penetration speeds when in bumpy air? a lot seam to confuse the Vra with the Vno speed. (yellow arc) and when loaded sometimes above MTOW as some bombers are when fully fuelled, the Turbulence penetration speed, Vra, comes down significantly. and in rough, windy weather with a huge amount of thermal activity from fires, its easy to see how a waterbomber can break up or severly reduce its fatigue life.

 

Sadly it happened to a C130 Hercules crew in california a few years ago.

 

 

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i was thinking along similar lines, how many pilots actually observe the turbulence penetration speeds when in bumpy air? a lot seam to confuse the Vra with the Vno speed. (yellow arc) and when loaded sometimes above MTOW as some bombers are when fully fuelled, the Turbulence penetration speed, Vra, comes down significantly. and in rough, windy weather with a huge amount of thermal activity from fires, its easy to see how a waterbomber can break up or severly reduce its fatigue life.

Sadly as experienced as these pilots may be, they'd no doubt be under a lot of pressure and may push the boundaries, even if it's personal pressure to make their activity really count in making a difference to the situation ahead of them. I can imagine that the turbulence above all that rising heat would not be for the feint-hearted.

 

As sad as this event is, we have to be very grateful for his contribution, for which his family can be justifiably proud, despite their sad loss.

 

R.I.P.

 

 

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Actually not. The formula for fatigue is miners rule... check the other axis of the curve...

Not clear to me what you mean. The Dromader is based on the Ayres Thrush - probably pretty close to the Bull Thrush (R1820) and I've seen quite a bit of that spar design. It's a non-tapered cantilever wing, and the spar caps are steel - but the web stress at the wing root is a major problem in that wing. I've done plenty of fatigue life calculations using the cumulative damage hypothesis - it's standard practice, see FAA AC 23.13B - and a small increase in the 1-G stress makes a big difference to the fatigue life. The cumulative damage sums go out the window when the MTOW is arbitrary. The agricultural operators have been in denial about fatigue for decades. So, it would not surprise me if that accident was a fatigue failure; but we are hypothesizing ahead of the evidence.

 

 

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Guest Maj Millard

That particular C-130 had been used by the CIA reportable to carry gold. When they were asked how many hours it had done, by the US ATSB , the CIA refused to give any info .........................Maj....027_buddies.gif.22de48aac5a25c8f7b0f586db41ef93a.gif

 

 

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Guest Maj Millard

Early reports said the wing failure was on an Airtractor 802. Anyone who has inspected the massive wing carry through on Airtractor would find that hard to imagine how one could break, except in extreme circumstances. I know nothing of Dromaders, but I would imagine they would have to be similar. Being chemical bombers, a leaking hopper which is situated right over the main spar, creates a corrosion problem if not watched closely.

 

I know on the Airtractor the huge hopper has to be removed from the aircraft periodically to properly inspect the foward surface of the spar for any corrosion or other damage.......Condolences to the family of the lost pilot..............Maj......

 

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