Lockheed Stress Memo 88

[aerostruct1979]

Hello,

I need the Lockheed Stress Memo 88. Where can I find this document in pdf? I tried at emule but it is quite dificult to find.

Does anyone have a hint?

Thanks a lot!

 

[bf109g]

As with all proprietry data, you will find it difficult to find what you want. The OEM's are notoriously stingy with these documents and they keep an eye on the internet to make sure that people are not distributing this things willy nilly in cyberspace.

All of what I have has come from back-channel personal contacts. You may want to call in a few markers to see if anybody has what you want. I don't believe you'll find anybody willing to cough up SM 88 in a public forum.

 

[aerostruct1979]

Oh My!

I've already found it!

The complete Lockheed Stress Memo Manual!!!

Guess where?

eMule!!!

I finished dowloading it yesterday after almost 1 week with my computer on (24 hours per day).

 

[bf109g]

Aerostruct -

Just curious, what is the date on that?

Glad you found it. I have to admit, I've never used eMule until today. There are few things I've been trying to add to my library but have yet to find. Perhaps eMule will yield some results!!!

 

[RPstress]

Theoretically, Lockheed's (well, LockheedMartin's or whatever they're called this week) lawyers are now tracking you down...

Does downloading a document for personal use constitute breach of copyright in the US? I would think that the people who made the document available via e-mule are guilty of breach of copyright, although because of the fragmented nature of the process (usually with multiple providers of different bits of the document) it's far from clear cut. If it's an ancient document from the '50s then that's one thing, but if it's the company's up to date manual...

 

[edbgtr]

For users of this forum, it should be noted that it is very unlikely that Lockheed’s lawyers will be tracking anyone down over the use of this stress memo. In their text they haven’t even given credit to the original creators of this work, i.e. North American, if my sources serve me correctly.
An old friend of mine, who worked for many years as Head of Methods at a large airframer in the Dallas area, once told me that every US aircraft company has a copy of their competitor’s structures manuals. Where there were gaps in their own manual, the competitor’s data were included and a few “confirmation tests” done to verify the “foreign” method. Thus you’ll find a very large amount of uniformity among stress manuals emanating from US companies.
Differences do appear in SM material and fastener allowables however, where very often different suppliers are able to achieve statistically better results than those published in the public domain literature like the MMPDS. Similar materials (e.g. 2024) are given additional identifiers relating them to the supplier.
Much of this work has also found its way across the pond to Europe, with some sloppy disguise work done, in particular, on commercial aircraft fatigue analysis methods.
In particular the L-SM 88 method under discussion here, on Tension Fittings, has found its way into European manuals, then migrated to Ireland and has finally wound up back in Canada, with the European “tweaks” still evident in the fine-print. At least the European company did some substantial mathematical and FE analysis work on the empirical methods to confirm their validity. They have their own internal substantiating reports to back-up their use of the original.
Most of today’s manuals still rely on the ground-breaking work done by the NACA researchers before during and after WW2. The works of Kuhn and Gerard et al are enshrined in each one.
Besides the inter-company “flow” of manuals, ex-company SM authors have shared their company methods and test results with us in the form of public domain books and supplements that are now widely used by stress engineers around the globe.
IMHO, the L-M lawyers would have an extremely tough time convincing a jury that they were the sole owners of the text contained in L-SM 88. But who knows, in order to turn a buck, maybe they’ll try anyway.

 

[aerostruct1979]

The date of LSM 88a is:

15 DECEMBER 1955
REVISED JUNE 1988
REVISED NOVEMBER 1992
REVISED APRIL 1995

That's it.

There is no problem at all obtaining a stress manual. Summarizing what edbgtr said, the information is spreaded away....everybody uses available information.

 

[aerostruct1979]

If you buy Michael Niu - Airframe Stress Analysis And Sizing.

You will find the LSM 88a in it.

It's already a public information.