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Posted

Yeah, I've been up in a Dragonfly. Real thrill that was, like going for a ride in a flying Bondi tram.

 

And what about the pilot of the DC4 leaning right out of his window to slam the side door shut - bit how-ya-going that was.

 

 

  • Haha 1
Posted

From the slope of the cheat line on the fuselage, and the fact the props are so close to the open window, I'd say it was definitely a DC3. and I dont think any door on a DC4 was that close to the cockpit window.

 

 

 

Edit: Nev posted while I was typing.

Posted

Interesting response: A circle, and hence a sphere, is a special type of ellipse (oval). Also, a square is a particular type of rectangle, and an equilateral triangle is a special type of isosceles triangle.

 

My Dad had a near-feral tom cat which was a champion rodent catcher. Dad called it a ball-bearing rat trap.

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  • Haha 3
Posted

No, they're oval, but only very slightly oval, and oval oddly, meaning the bearing tracks are ground to have two or three irregularly spaced hollows to counter harmonics which were cracking the bearings at 20,000 RPM or what ever the high revs are. Too much for the bearings anyway, and something had to be done about it, and that's what they did. Perhaps they are not really a true ovality, but they are certainly not round either.

  • Informative 3
Posted
9 hours ago, Grumpy Old Nasho said:

Perhaps they are not really a true ovality, but they are certainly not round either.

"Ovality" is a word derived from the Medieval Latin ovalis "of or pertaining to an egg", leading to the French ovalle "oval figure," describing a 2-dimensional figure in the general shape of the lengthwise outline of an egg.

 

In describing a shape, oval and ellipse actually have different meanings. An ellipse is a specific type of oval with a precise mathematical definition, while an oval is a more general term for any shape resembling a squashed circle. The shape of a cam is oval, while the shape of a ball bearing is elliptical (the special type of ellipse called a sphere).

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  • Informative 1
Posted
20 minutes ago, Marty_d said:

That's interesting.

So all football/cricket fields should have their name changed from "oval" to "ellipse"?

That's where the vocabulary of the layman and the specialist collide. I see no problem with using a tern derived from the observation of common things, in this case the shape of an egg, in non-technical situations, and the use of the specifically defined term in technical situations. Context is important. Do you kick a ball or a sphere across a sports oval, or depending on your preferred game, an ellipsoid?

Posted (edited)

The greatest bearings I've ever encountered were in the rear axle of a German Magirus-Deutz truck I owned from 1967 to 1975. Magirus-Deutz was a fire-engine manufacturer from 1899, and they went on to produce a long line of road trucks. The company was absorbed into Iveco Trucks when Iveco was formed by Fiat.

They built the cab and chassis, and used air-cooled Deutz engines with ZF gearboxes and rear axles. The ZF rear axle in my truck was only single drive, but it was rated at 12 tonnes load capacity, unlike the normal 8-9 tonnes of most truck axles.

 

This axle contained barrel roller bearings, and these bearings are a heavy duty bearing that can cope with major deflection in load angles and high shock loadings.

Thus, the axle was designed to cope with bending of the axle housing under severe overload conditions. The rollers in barrel roller bearings are essentially an oval shape.

 

Edited by onetrack

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