FMTV up close

[cranetruck]

Thank you Bob for your interesting responses!

More questions:

When you see the 15W etc requirement, how far from an original or previous design can you stray, could you go to a dual front axle design if that has some advantages or are you to stay within certain boundaries? Can you simply redesign the seat to be more "absorbent/tolerant" of these forces, or would that be assigned to a different group?

What requirement led to the closed cab-over design and the single front axle configuration?

A long time ago, I worked on a McDonnell Douglas project and we were testing a cockpit display to determine if the intensity of the symbols met the Air Force specifications. The requirement was for them to be visible in sunlight, but the spec was in lumens/square inch or something like that.
Of course, my suggestion that we bring the display outside in the sunlight didn't go over too well.

 

[emr]

Bob, I like this post and love to agree or disagree, I take it with a smile and love to poke, I sure can take it too, and I actually like it, But I would never compare the 2, that is what i was saying, there is no comparison in my eyes, The Marine truck is what all trucks shoud be as long as it was not so dam tall, But there is alot to be said for simplicity,they went for a 7 ton tried to put both trucks in one, is it working,? it is a monster fure sure. but then again where is that line anyway, we sure don't know, Joaquin's truck is awesome in my eyes too,Having something that is/was a proto type is sure one heck of a cool thing...I would be proud to own it.A mission ready truck, what about a good percentage of the guys one will carry will break a leg? I love ALL MV's...and for what they stood and stand for, I think U have taken alot of the mystery out of this for us, for that I say thanks, I have learned alot, and hope to learn more, As I have stated in the past, I have opinions, alot of them are from hands on, I believe for the most part American Industry does a very good to Great job, But like everything else It is subject to scruitiny. most things designed are changed , I am a firm believer hind sight is 20/20, and after it is driven it may need a complete overhaul ,true in many cases of history and some of the worst like the P51 Mustang went on and/or others will go on to make history again and again.I like anything Green, The Real Green no tree hugger here... Randy

 

[BobS]

See inline comments in LARGER TEXT:

Thank you Bob for your interesting responses!

You are welcome.

More questions:

When you see the 15W etc requirement, how far from an original or previous design can you stray, could you go to a dual front axle design if that has some advantages or are you to stay within certain boundaries? Can you simply redesign the seat to be more "absorbent/tolerant" of these forces, or would that be assigned to a different group?

It depends on the original program requirements, in that some designs are best met with a SLEP (Service Life Extension Program) much like the M35A3 was. Others, like FMTV was to be a "no holds barred" complete re-think of how the military performs it's tasks and what tasks may be better handled by other vehicles (the current -and ongoing for the last 40 years- argument over the Force Protection APC's, the Navistar APC's, and M113 variant APC's, for example). Where a guy like myself comes in is at the point of "trade off studies", in that we create paper vehciles of various configurations to attempt to optimize the TACOM requirements. All these "proposals" are then evaluated by the prospective manufacturer to determine exactly which approach would make the most likely winner of the contract. The FMTV program at GM/MVO (far earlier, by 2 years than the eventual TTC joint venture with BMY-Harsco, the winner of the M35A3 contract) was initiated on a "draft" (not a finalized) RFP (Request for Proposals) from 1981.

MVO was a unique group, in that there were actually only 3 of us that had any military vehicle experience (and I was the noobie of the group). Out of over 50 people, the 3 of us (2 program engineers and myself-the lead design engineer) came up with (as I remember) over 20 different vehicle design concepts, biasing each to a particular failure of the M35/M809 series of trucks in field use, based on personal experience. We built (I don't mean just worked on papaer and supervised techs', I mean we got dirty and burned up pants from welding, mashed toes from dropping steel, etc....real work, in other words ) 3 prototyped, based on the British MoD's Bedford trucks that were repowered with american drivelines (DDC 8.2's and Allison transmissions) to simulate the configurations we felt best met the requirements, then commenced pseudo-military performance testing to determine durability of these concepts, off road performance, etc. We then started a "production intent" design based on the results of these tests, one that provided the least amount of cost, carried over necessary components from existing vehicles (mostly electrical system), and provided the cheapest cost that still met the objectives.

The upshot to this is yes, playing with a seat, suspension, and any other component is valid at this point.

What requirement led to the closed cab-over design and the single front axle configuration?

Sound level measured at the driver's right ear-sorry but I do not remember the exact value. The spec came from the M35/M809 right hand mounted verticle exhaust stack.

A long time ago, I worked on a McDonnell Douglas project and we were testing a cockpit display to determine if the intensity of the symbols met the Air Force specifications. The requirement was for them to be visible in sunlight, but the spec was in lumens/square inch or something like that.
Of course, my suggestion that we bring the display outside in the sunlight didn't go over too well.

Yep, I can understand that....also I can understand the response you got. Repeatability for verification in a lab is a prime requirement of the IP's in a truck are also an issue. We ended up spending over $100,000 on a test fixture and certification testing in the Milford (GM Proving Grounds in Milford, MI) photometrics labs.

 

[cranetruck]

Thanks again Bob for sharing....so driver comfort considerations rate pretty high then?

 

[BobS]

Not for comfort's sake, but from a crew longevity standpoint. Think of it this way-drive a CUCV (M100 for 12 hours straight, stopping for only a refuel. Now drive a Caprice for the same distance, for the same length of time. Which one can you jump out of and go run a confidence course?



Best as always,

Bob

 

[emr]

Bob, Your insite and info would make a GREAT read in the MV Mag. we sure are lucky, I think, to have U on board. No other place could one get this inside info.All I have learned and the money i have saved from this site was well worth My donation 2 fold...Thanks randy

 

[BobS]

You are welcome Randy. Unfortunately, I don't know if my "comments" would be of interest to the general readers....as Joaquin has said, I tend not to play well with others and once I get talking.....



Best as always,

Bob

 

[cranetruck]

Not for comfort's sake, but from a crew longevity standpoint. Think of it this way-drive a CUCV (M100 for 12 hours straight, stopping for only a refuel. Now drive a Caprice for the same distance, for the same length of time. Which one can you jump out of and go run a confidence course?



Best as always,

Bob

You are asking me! I drove the deuce cross country and back, sleeping in the cab mostly and loved it.
..of course being over sixty may have something to do with it in a convoluted way....

 

[emr]

I spent 15 hours in a deuce drivers seat the longest for me one way , and I slept for 15 hours right after that ...Randy

 

[vinny-socom1]

I love the look of the LMTV trucks but I heard they are top heavy?? still look good to me !!!

 

[cranetruck]

Not for comfort's sake, but from a crew longevity standpoint. Think of it this way-drive a CUCV (M100 for 12 hours straight, stopping for only a refuel. Now drive a Caprice for the same distance, for the same length of time. Which one can you jump out of and go run a confidence course?....

These trucks (FMTVs) are designed to be troop carriers as much as moving general cargo, what about the troops in the back who would actually be the ones to run the confidence course at the end of the day? Any consideration here (not from an engineering point of view, but in the general requirements)?

 

[emr]

They come with an intercom to the driver right in the cargo area so they could say "hey stop we need more beer" Oh that was the 80's...OR ...Hey U Jerk slow down that could help.might be considerd a consideration? ,Randy

 

[BobS]

Not for comfort's sake, but from a crew longevity standpoint. Think of it this way-drive a CUCV (M100 for 12 hours straight, stopping for only a refuel. Now drive a Caprice for the same distance, for the same length of time. Which one can you jump out of and go run a confidence course?....

These trucks (FMTVs) are designed to be troop carriers as much as moving general cargo, what about the troops in the back who would actually be the ones to run the confidence course at the end of the day? Any consideration here (not from an engineering point of view, but in the general requirements)?

Yes, actually, there was, on ingress and egress from the truck bed. It actually was a sore spot with me, personally. On the MVO truck, we had ladder steps built into the tailgate, which was easier to get into than the S&S truck, BUT neither was "good" in my opinion.

The problem came from the simple geometry of packaging and departure angle. I can't remember how many times I fell off the back of that damn thing trying to get in and out of that bed design. It had a LOOONNNNGGGG last step getting out. I never broke anything, but that did not alter the damage to my ego while performing a demo for management from MVO and I ended up teaching some of the fairer sex engineers new descriptive terminology about TACOM and their "requirements"...... ....oh, well.

Best as always,

Bob

 

[cranetruck]

The FORD engineers solved the step-up/down problem this way back in '69.

 

[emr]

That truck seems to be alot lower to the ground than the newer skyskrapers of today, Something that slides right out of the top of the tailgate itself when slung down and then ridgidity would be an issue,and anything that movs breaks eventually, the tailgate of M series trucks has the step/handle/loop on top and works well. Then the new F series trucks have options like this and is also nothing new, seems everything has been done by somebody by the year 2008, just getting the people designing on to agree on, ...randy

 

[cranetruck]

That truck seems to be alot lower to the ground than the newer skyskrapers of today.....randy

Hmmm...the deck level of the 5-ton m656 is 54 inches above ground....note my avatar, tires and frame relative to those two guys and the deuce.

 

[emr]

Just my view from the black and white photo, it looks like the bed is right on the tire of in that pic,...Randy

 

[cranetruck]

Just my view from the black and white photo, it looks like the bed is right on the tire of in that pic,...Randy

This should give you a better idea....tires are 42 inches tall.