Remember the many holes (windows) an airplane has?
 

As an architect, we are familiar with structural components which have many holes, such as airplanes with their many windows. They are none the less strong for the "holes".

Wheel are similar. Strength is not reduced, if the holes are "engineered" correctly (as the airplane windows are).

The reason that wheel manufacturers do this, is to avoid stocking many different wheels with many different bolts centers and sizes. Note that some companies design over-size holes, then require you to use washers to make the holes bolt-centric.

But your concern is well-founded; such wheels can't be as "good" as ones made specifically for your car, your bolt pattern, your hub-centric condition. And generally they weigh much more, too.

Then there were the airplane windows of the DeHaviland Comet jet of the mid-1950s.........a MAJOR structural failure in this area caused these promising planes to be grounded. Square windows just did not work - too many stress risers.

Craig
@RS

Ahh the DeHaviland comet. . . square windows, to crack at the corners with every pressurization/depressurization cycle, and no-bypass turbojets located in the wing root, so when you lose a compressor blade, you slice through the main wing spar! Ever wonder why modern jets have the engine so far ahead of the wing leading edge? It ain't aerodynamics or weight reduction!

The Comet may have been a deathtrap but it sure was beautiful.

Holes (windows) in an aircraft and holes in a wheel are two different things. In an aircraft, the windows are holes in a pressure vessel. If you do the math, there is a huge amount of force pressing outward on the skin of an aircraft once you get above 8-10000ft.

Mike

Hey, John! Ever see the 1951 Jimmie Stewart movie <i><b>'No Highway in the Sky'</b></i> ??? A bit of Hollywood mumbo-jumbo about nuclear fission in aluminum atoms ... but, nevertheless, a predictor of metal fatigue as a major problem in jets ... a couple of years before the Comets started falling out of the sky! Makes you wonder if a disgruntled De Haviland employee wasn't a factor in the screenplay?

Re: Remember the many holes (windows) an airplane has?
 

Ah, ever seen the inside of a modern day fuselage without the interior bits? There is a lot of reinforcement (and extra weight) around those windows. Generally the fuselage is much stronger and can take more cycles (landings and takeoffs, with pressurization) without the windows. Take a good look at a OEM designed and built cargo plane...no windows.

I was a Boeing 737 engineer for 14 years. Without windows, a fuselage
is a remarkably simple structure:

Stringers (looong U-shaped pieces which run fore and aft)
Stringer clips (which hold the stringers to the fuselage ribs)
Ribs (circular/circumferential pieces at every body station - vertical pieces)

The window areas are a PITA to machine and design. Holes in a fuselage do not help an aircraft ;-)

Left Boeing to start my own Porsche business.

Craig
@RS

It would be better, in my opinion, to have LCD screens where the windows are, with external cameras, to provide "synthetic vision" to the passengers. You could pan, zoom, IR to shoot through clouds/precip, and auto-dim the screens.

You know I had this same idea for the interior cabins on cruise ships. If we got together we wouldn't have to drive these old beat up Porsches, we could buy new ones! :)

Put the LCD screens in the arm rests, make them so they fold out on articulating arms and you've got it...oh wait, they already have that...only in 1st class though :(

This definitly belongs in O.T. but is way-interesting.

The stuctural integrity of a piece of a hollow tubular frame during a varied vibrational cycle.
[edit:I wasen't making too much sence when I typed this. Sorry]

Hey now! This is a family site!

Warren -
I've seen that freaking movie. I think I was nursing a post-overserved condition one afternoon and it was on AMC. Goofy film.

In a prior life I did some naval architecture, and the rule is never a square corner -- all the stress "focuses" on corners and the failures are often spectactular and w/o warning. Coaming helps some, but you're specifically designing in failure point if you add a corner.

JP

Comet Crashes due to fuselage breakup

G-ALYP 10 January 1954 35 Fatal
G-ALYY 08 April 1954 21 Fatal

If you look at the other crashes, more than two were caused by stalling the aircraft (overrotation). So in addition to round windows, it sounds like the Comet needed a stickshaker also.

Son-of-Comet!

http://ciel.me.cmu.edu/soji/photo/02...and/nimrod.jpg

http://www.airventure.de/airventurep...at99nimrod.JPG

http://www.shanaberger.com/images/Nimrod.jpg

Maybe we could go on an LCD vacation too... It's a nice idea, but i dont think itll provide quite the same effect.