Re: [CR] So-called death stems... Now AL failures in planes and bikes

(Example: Bike Shops:R.E.W. Reynolds)

Date: Tue, 17 Jan 2006 08:45:37 -0800 (PST)
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
Subject: Re: [CR] So-called death stems... Now AL failures in planes and bikes
To: gpvb1@comcast.net, classicrendezvous@bikelist.org
In-Reply-To: <011720061618.13086.43CD18F00007D58E0000331E2207000953CE0D909F09@comcast.net>


Just saw a TV show on this very recently. That they did not crash was a miracle. They diverted from their Oauhu destination to Maui for an emergency landing, then on approach could not confirm that the landing gear was locked, then, as if they needed any more problems, one engine failed. It was a heroic effort on the part of the crew to land safely. One fight attendant was sucked out of the plane when the top first tore away. Miraculously, no one else was killed.

Airframes it seems have long been the laboratory in which failure modes of aluminum alloy are discovered. I believe fatigue failure of aluminum was first understood after several crashs of the first jet airliner, the DeHaviland Comet, shortly after WWII. There was a 1950's movie, I believe starring James Stuart, about this subject. I guess we should be thankful the phenomenon was not discovered due to Coppi, Bartali or Bobet crashing over a cliff in the TdF. The truth of course, is that the magnitude and number of stress cycles experienced by an airframe is exponentially greater than a bicycle part will ever see.

Regards,

Jerry Moos Big Spring, TX

gpvb1@comcast.net wrote: It's apples and oranges. The airplane didn't crash, but landed safely. Not true for a bike with a broken stem.

Greg Parker
Ann Arbor, Michigan


-------------- Original message --------------
From: "Jerome & Elizabeth Moos"


My point was more the public reaction than the circumstances of the failure, i.e. a spectacular, exhaustively documented failure does not cause panic, but vague rumors can cause parts to be labeled a "death" whatever. The one similarity is that we are talking about fatigue failures of aluminum structures.

Regards,

Jerry Moos Big Spring, TX

gpvb1@comcast.net wrote: Just FYI, that famous 737 failure occurred on a plane that had experienced something on the order of 300,000 compression / decompression cycles. It was a short-hop aircraft that had made over 300,000 take-offs and landings! It caused Boeing to re-write the maintenance specs. for 737s. It has absolutely nothing whatsoever to do with bicycle parts breaking.

Greg Parker Ann Arbor, Michigan

Date: Mon, 16 Jan 2006 14:47:35 -0800 (PST) From: Jerome & Elizabeth Moos To: oroboyz@aol.com, hdarr@localnet.com, dartley@co.ba.md.us, classicrendezvous@bikelist.org Subject: [CR]Re: So-called death stems; where exactly.....

I've never had one fail, although I'm sure some do, as do some Cinelli and TTT stems. It would seem SOMEONE must have experienced such a failure, or perhaps heard rumors of such failures, else where did this "death stem" thing come from? Unless the Cinelli and TTT marketing boys just manufactured the whole thing to trash the competition.

Funny thing, one of the most spectacular failures of an aluminum structure, in which most of the top of an Aloha Ailines jetliner tore away in mid-flight some years ago, is absolutely undisputed and exhaustively documented. Yet no one speaks of "death planes" and the incident didn't seem to scare people away from flying, at least not for long.

Regards,

Jerry Moos Big Spring, TX

oroboyz@aol.com wrote: ...do they fail? Anyone? Anyone? Ferris? Ferris Bueller?

Dale Brown
Greensboro, NC USA