jensenracing77

I was at the GM Heritage Center a couple weeks back doing research on the 62 63 Jetfire. While looking through all the information I found a large thick book for each year that had each and every part listed by weight. Down to every screw or plastic fastener. Had every part of a car listed in this book. I am wondering why they needed this recorded in a book? I have thought about it and just can't think of a reason for it. Anyone have any ideas?

joe_padavano

It's called mass properties engineering, and it is a fundamental part of the design process. The weight of the car drives structural design, suspension design and tuning, engine HP needs, tire sizing, fuel economy, brake sizes, wheel bearing sizes, etc. Those sizing decisions need to be made long before there is a prototype vehicle to weigh, so you must bookkeep estimated and calculated weights. Front/rear weight distribution matters also, and this tabulation lets you calculate that as well. These mass properties reports also facilitate design trade studies. For example, it might be less expensive to fabricate a certain part out of cast iron instead of aluminum, but the resulting increase in weight might require larger and more expensive brakes. This is all part of the engineering process. If you think this level of weight documentation and control is a lot, you should see what we have to do on satellites where every pound might be worth $10K or more in other costs.

jensenracing77

Very cool to know. Thanks

oldspackrat

Joe, I didn't know you worked on Plymouths?!?!

joe_padavano

:d

1969w3155

Eric, what is the process to go the GM center and search through the records? Do you call and make an appointment?

jensenracing77

A couple other guys well known to the Heritage center put a good word in for me. it was about a year process before I was able to go. You need to have a specific thing in mind to look at and they will bring you the files. You do not get to just look as you please. Also helps if your search is specialized in one particular model. It is good and bad. The good is that you do get really good information. The bad, you can not make copies of anything, can only take photographs and then you are not allowed to share it.

1969w3155

Thanks Eric. I have a friend who would really being interested in going there for research, and has a nose for this type of thing. He has a Masters degree in history, and is always rooting around car stuff to glean what he can. He is up the road in Grand Blanc, Mi. So, not much of a drive.