RE: [CR]Holy mackerel, 76 Masi Prestige Fiera


From: "RB" <2wheelseal@earthlink.net>
To: "CR" <classicrendezvous@bikelist.org>
Subject: RE: [CR]Holy mackerel, 76 Masi Prestige Fiera
Date: Wed, 2 Nov 2005 23:28:45 -0800
In-Reply-To: <1e3.4817fb12.309b121f@aol.com>


If I'm reading the following correctly, I have to agree with Bob on both accounts.

A) It's a show bike thing, for all the reasons he mentions, plus, it just looks really cool and different.

B) It appears to be borrowed from aircraft engineering - remove material from a structural member in one place, and put it back in at right angles, creating an internally braced structure ('truss'), without resorting to additional external bracing. How much this actually does in this application I can't tell, but it was highly effective in early (perhaps even late) aircraft construction. Particularly before the advent of the highly engineered materials more common today.

-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org]On Behalf Of BobHoveyGa@aol.com Sent: Wednesday, November 02, 2005 11:11 PM To: classicrendezvous@bikelist.org Subject: [CR]Holy mackerel, 76 Masi Prestige Fiera


>My respect for Masi has, for the first time, dropped.

Don't take it too hard Harvey... think of all the impractical whimsies you've seen in showbikes over the years from just about every manufacturer. While this type of construction may have some structural advantages (see below), I think it was more about appearing at the bike show with something that might impress the other builders a bit and (most important) draw a nice crowd at the booth.


>Whether you think that the primary load on chainstays is a twisting one, or side by side, this mutiliation ain't gonna help the strength of the rear triangle. Unless testing or finite element analysis proves me wrong, this isn't decoration like tail fins, this is harm to the structural integrity. I hope I am wrong. harvey sachs mcLean va

If the holes are lined with steel tubes as the owner has said, and they're close to the same thickness as the stays themselves, then I could see some benefit. Whether the returns would justify the massive amount of effort is questionable, but I've seen structures like this in aircraft and they apparently do add strength. It is basically a truss, just using tubes rather than diagonal cross members. The way they are oriented, vertical stiffness is probably a wash, but torsional and lateral stiffness is almost certainly improved.

Bob Hovey
Columbus, GA