Tying the aircraft down

[rgmwa]

19 minutes ago, Blueadventures said:

This is the bracing (Fly and cross) for our Northern Queensland ratings.

Just out of interest, these are the various wind speed regions for Australia:

If you're in coastal Northern Qld, you'll be in Region C (cyclonic). The number after the letters (eg A0-A5) denotes different wind speeds coming from different directions for each region, and can be used to fine tune a design. The typical basic design wind speeds in each region are:

           A 45m/sec (162 km/hr)

           B 57m/sec  (205 km/hr)

           C 66m/sec (238 km/hr)

           D 80m/sec (288 km/hr)

 

 

[onetrack]

Well, the willy-willies they measured might have only travelled at those low speeds, but I can tell about some personally viewed experiences of mini-tornadoes in W.A., that would indicate wind speeds in excess of 200kmh.

In July 1975, at my minesite at Higginsville W.A., I endured a frightening night of howling winds from a major storm that travelled through the Southern Goldfields and S.W. W.A. I was sheltering in a 3-room former railway fettlers hut, a very sturdily built timber building, that was built in 1907, when over-building for strength was the order of the day. I'd transported 4 of these buildings to the mine in 1972, from the nearby Pioneer siding, when the narrow gauge line was upgraded to standard gauge in 1971.

I would estimate the consistent winds that night, of around 70-90kmh, with gusts around 100-110kmh. 

In the morning, I drove S into Norseman, down the Coolgardie-Esperance Rd, and about 10kms S of my mine, a mini-tornado had left a trail of destruction through the native vegetation on the Eastern side of the highway.

 

Now, the vegetation in that area is hefty stuff, big Salmon Gums, decent-size Gimlet trees, and Goldfields Blackbutt trees, interspersed with lighter scrubby trees and bushes.

But there was a strip of country there, that looked like someone had dragged a clearing chain between two bulldozers along it.

Big Salmon Gums, a metre wide at the base, had been screwed off about 1.5-2M high, leaving shattered stumps. There wasn't a single tree left intact over a length of probably 700-800 metres, and about 100 metres wide.

It was total and utter devastation, and it was caused by intense cyclonic wind, and nothing else. I wouldn't have liked to have been in a building in that mini-tornado's path.

 

I've seen the results, in the wheatbelt, of multiple numbers of farm sheds that were destroyed by mini-tornadoes embedded in storms. Some of them were sturdily built from RSJ (I-beam or Universal Beam, or Universal Column, as they're called today), with structural steel trusses.

The tornado-like winds just blew them apart. In one case, the mini-tornado picked out a single shed in amongst a group of sheds and a house, and destroyed that single shed, and nothing else.

It was like the mini-tornado had simply fallen out of the sky onto that single shed.

 

I have great respect for what concentrated strong winds can do, especially when they're in storms embedded in strong cold fronts, or in thunderstorms.

 

Edited 4 hours ago by onetrack