BCM Community

Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: HighTechRedneck on April 03, 2010, 09:35:05 AM

Title: How much of a GM 5108's strength is from the shell?
Post by: HighTechRedneck on April 03, 2010, 09:35:05 AM
What happens when you remove the shell and the structural strength it proivdes?

The first photo is an GM 5108 "Old Look"  for reference.

The second is a photo of a GM 5108 that is being scrapped right now.  Everything above the floor has been removed.

(I corrected the original error of thinking that chassis had been an MC-5.)
Title: Re: How much of an MCI's strength is from the shell?
Post by: rgrauto on April 03, 2010, 09:56:45 AM
That does not look like a mc5, Where is the bays?  thank's Glen
Title: Re: How much of an MCI's strength is from the shell?
Post by: HighTechRedneck on April 03, 2010, 10:19:01 AM
I stand corrected, the MC-5 was the last bus they scrapped.  This is another one.  This one was a GM 5108 "Old Look" transit.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: zubzub on April 03, 2010, 03:51:46 PM
we can't really know, but is it possible it bent that much without being loaded?
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: DaveG on April 03, 2010, 04:29:00 PM
wow, a bus bone yard...oboy oboy!
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: jackhartjr on April 03, 2010, 06:58:49 PM
ZubZub, my guess is that yes it did!  No support!
Jack
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: HighTechRedneck on April 03, 2010, 07:28:18 PM
Correct, it didn't sag until the bus shell was cut away.  This is because it is a monocoque design.  There are no front to back frame rails underneath.  The bus body is structured to provide the strength.

In that particular bus, there are frame members coming forward about 6 feet from the rear axle section.  Very much like on my RTS.  But forward of that, there are no large frame rails at all.  I took a bunch of photos this evening that show this.  I will post them soon.

I also photographed an MC-9 that is next up on the chopping block and has had many panels and pieces removed already.  It is easy to see that same monocoque design principle there.  Even more so in that there aren't even the frame members coming forward from the rear axle section typical in the GM designs.  The load is transferred to the body immediately instead of over the span of several feet.

Dave, this is one more reason to come see the world headquarters of BCM. ;D  This is at the Choo Choo Express Garage.  Scrap metal prices are coming back up and they are getting back to scrapping buses.  It is amazing (and saddening to a bus lover) how fast they can tear them down.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: mikewarmblood on April 22, 2011, 04:34:29 PM
I hate to see buses scrapped.  God I can only hope metal prices plummet or all used buses are in trouble.  It breaks my heart to see that.  Old looks are getting realy rare.  I hope to find one someday.  Mike.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: artvonne on April 22, 2011, 05:23:14 PM
  Thats what GMC's do when you skin em out. In that picture, there isnt anything holding it together other than some angle iron running lengthwise, and the wood floor.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: mikewarmblood on April 22, 2011, 05:30:00 PM
Are there any  other bus companies that does that besides GMCs?  I know that most buses use tubular frame or spaceframe through the walls and roof.  If you take the skin off them they still hold together. I thought all buses were like that except schoolbuses then I am finding out that fishbowls and GMCs of that era  uses the skin and wood floor as structure.  I am now worried about my Flxible.  Although under the Flxible there is much more frames and structures than a fishbowl.  On a Flxible Newlook is the floor just what it is a floor??  There are a lot of framing going across the bus every three feet and there is a bunch of tubes in the front and lots of angle iron and tubes and plates in the last 15 feet of the bus? are there any Flxible experts on here? that can explain it better than I understand it? and is the Flxible tubular framed?  I thought the fishbowls were tubular as well but guess not.  Thanks Mike.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: artvonne on April 22, 2011, 05:55:18 PM
  Its really nothing to worry about. The skin is heavier, like 1/8th inch with ribs, its pretty strong stuff. The curved roof adds even more strength to the structure. The bubble shape end caps are steel, and incredibly strong. On an OTR coach like a 4104, 06, 07, 05, 08, etc., the cargo bay floor being tied to the bulkheads, and the catwalk running under the center isle, add even more structural rigidity to the structure. You need to examine how aluminum aircraft are constructed. GMC's are simular, but much, much heavier and stronger. They wouldnt still be around after 70 years if they wernt strong.
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: mikewarmblood on April 22, 2011, 08:01:58 PM
Oh I have no doubt that a GM is agreat design.  I am just comparing a GM to a Flxible.  The Flx is like a Ford compaired to a Chevy when we talk buses. Fords have somethings that are much better than compared to Chevys  and vice versa.   I look under my Flx and looks like a lot of framing compared to the Fishbowl.  So I am wondering if the Flx has a skeleton unlike a Fishbowl.   I think the engineering was really a marvel with GMC very precise.  Whereas the Flx just looks so much heavier than the GMC cause they couldn't engineer something that light and as strong as a fishbowl and the looks are the best  I think the fishbowl is the most beautiful transit bus ever built.  Thanks Mike
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: RJ on April 22, 2011, 10:24:45 PM
Mike -

What's the story on that 4106 parked in the background of the sidewall-less Old Look?

;)
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: pvcces on April 22, 2011, 11:17:50 PM
mikewarmblood, all the Flxibles that I've looked at were lighter than the GMs. The axles were a dead giveaway; the Flex axles are much smaller.

Have you seen some that were heavier?

Tom Caffrey
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: happycamperbrat on April 23, 2011, 01:38:24 AM
Very dramatic photos Mike! If you come across an RTS that your scrapping, try to get a photo with just the side of the 3rd member cut out  ;)
Title: Re: How much of a GM 5108's strength is from the shell?
Post by: mikewarmblood on April 23, 2011, 06:46:38 AM
I would never scrap any bus.  That is like bus abuse LOL.   But yes an RTS is a tank and welded together.  All stainless except for the airbeams and axle substructures. Which are still a high quality steel that is not as rust prone as others.  I had an RTS the one that I lost due to a storage fee war I had to deal with,, long story short I lost. It was a 1983 40 by 102 inch and had a 6v92ta with the typical V730.  Unlike my 1978 it did have steel bulkheads and were in decent shape. They actually what I would call hybrid the tops were stainless steel about 8 inches from the floor of the bus down, Then the rest was steel.  I had another bus that was the same size of mine now 35 by 96 and the bulkheads were almost non existant and not sure how the bus was able to hold up. I just welded angle iron and rebult them.  IT is an easy thing to do if you can weld. I was looking on my Flxible title and the weight that is stated is 27,235 LBS and GVWR is 38,000 LBS  I need to take it to a cat scale and see what the weight really is. But my Gillig Phantom weighed 27,876 unlaiden weight.  So my Flxible weighs as much as my gillig.  I think a fishbowl weighs in at 19,000 unlaiden weight.  Not sure.  I have seen a Flxible starliner and it looks just like a fishbowl inside the walls but the Flx Newlook inside has all kinds of stuff in the walls looks like a bridge inside wierd but not sure if it is a skeleton or "birdcage" design or not.  But I wish it only weighed 10,000 would almost be able to take it to work every day. My RTS for being 35' by 96"  weighs as much as my Flxible. That is overkill.  Mike.