Brand new FMTV spotted

[BobS]

David, what percentage of the time are the trucks used to transport troops?
It may be a sensitive number, but the obvious point is that there should be a (possibly) new category of trucks, "armored cargo carriers".

Marines use the 7 tons as the primary mover of troops. We have a version called the "armadillo" just for troops and protecting them. Sorry, No pic. this time.

Bob, I appreciate your superior knowledge that you bring to the forum. However, if you had to pick a side of the fence, which would it be. Do you think an upgraded M35A2 would of been better platform than the whole FMTV program? Yes, I believe the FMTV may have better off-road capabilities, but how much better? Wouldn't the cost savings itself been enough to overlook the difference in off-road capabilities? Basically, would of a upgraded M35 platform meet 95% or more of the TACOM's new specs?

This is going to be sort of long-winded..so please bear with me....

There were several SLEP (Service Life Extension Program) projects on the M35's and M939's. The M35A3 was a great improvement for the 2.5T vehicle. Prior to FMTV (actually they overlapped for me) there was a program GM/MVO won called the MTD (Modern Technology Demonstrator) program. This was done on an M939 5T and consisted of an evalustion of potential components and technology for application to the FMTV program evaluation by TAACOM.

MTD was basically a new suspension, an early version of traction control (from Rockwell), STE-ICE integration on a new commercial engine (from John Deere- a 6466H), high travel leaf suspension, and EATON CEEMAT transmission (this trans was supplied by TAACOM), and finally, a low cost CTIS. One of the vehicle requirements was to be able to remove a powertrain (engine and transmission) from the truck in 20 minutes in the field with nothing else than a 5T wrecker and its toolset. I am not saying I agreed with this, but this iswhat I had to design into the vehicle.

To make a long story short, we met all the specs (we were actually able to do a hot engine R&R in 15 minutes and 20 seconds and were able to ground hop the powertrain on the ground from the truck electrical and computer system). The point to this is that the original M35 was (and still is) a decent vehicle, good for specific applications.

However, automotive technology and understanding is not static. As more and more vehicle applications are built, those of us doing this job learn more about how to make a vehicle more effecient, less complex, easier to service, easier to drive, better handling, safer, stop quicker, etc. Knowledge is not static.

As a result, it is not a fair comparison to compare a truck designed in the 1950's to a truck designed in the 1980's. There was 30 years of learning that simply did not exist in the 50's. They are as different as an M37 Powerwagon from a 2005 Dodge Powerwagon. (OK, I admit that is a bit of a stretch)

My point is, I like both-one is not "better" than the other. It all depends on what you are trying to accomplish. Using a rebuilt 40 plus year old truck to do today's job is not safe for the guys doing today's military jobs. Likewise, as Joaquin has found out the hard way...trying to use Libby as a personal vehicle, that is rock reliable in Baja, AIN'T the way to go without extensive OEM support. Apples and oranges.....

Sorry, I am not trying to evade your question. I am saying your question is not specific enough to form a definative answer. I would love to be able to own and use both.

FMTV is markedly superior to the M35 off road. At the Milford Proving Grounds (GM's PG in Michigan), I could take a loaded M35 around the track (including the 60 percent fore and 30 percent side slopes) in 5 minutes and 10 seconds, approximately. This was running the truck at the maximum speed I could withoout breaking anything. By comparison, the LMTV could run the same course in under 4 minutes at almost 2 times the speed. "Mobility is safety" in action.

The LMTV could also be loaded faster (it used an ISO style bed, instead of a fixed side as on the M35's of the time), had better balance (it was not tail heavy when loaded) so it stopped faster and straighter in panic stopping, the LMTV also could cool better than the M35 (seems like a small item, but the M35 could not ever pass the TAACOM cooling system specs the LMTV had to deal with-those changes came from the overheating issues the Israeli's had wit htheir M35's in the '67 war).

I apologize if that doesn't satisfy your request for a "yes or no" kind of answer. I simply cannot reasonably just "pick one" without any qualifications-they both have strength and weakness.

 

[NB1944]

Phil

Nice looking rig! We saw similar ones at the Vet's Day parade in Colo Sprgs last year. NB

 

[cranetruck]

Re: RE: Brand new FMTV spotted

....What's with the "No Step" on the bumper?....

Does not meet MIL-STD-1472E for clearance on the size 12W combat boot, so should not be used as a step.

Interesting response, makes me wonder about the constraints you had to work under.
It certainly would have made more sense to widen or placed the bumper a little further out since it would make an excellent step for reaching the windshield etc.

It also changes the meaning (at least by my understanding) of the "No Step" warning. Does it not usually mean that the marked area is not built to support a man's weight?

 

[cranetruck]

RE: Re: RE: Brand new FMTV spotted

BobS wrote:
......
FMTV is markedly superior to the M35 off road. At the Milford Proving Grounds (GM's PG in Michigan), I could take a loaded M35 around the track (including the 60 percent fore and 30 percent side slopes) in 5 minutes and 10 seconds, approximately. This was running the truck at the maximum speed I could withoout breaking anything. By comparison, the LMTV could run the same course in under 4 minutes at almost 2 times the speed. "Mobility is safety" in action.

Does the automatic transmission have anything to do with this? How long is the course?

The LMTV could also be loaded faster (it used an ISO style bed, instead of a fixed side as on the M35's of the time),

ISO existed at the time. The M656 had it in 1969.

.... had better balance (it was not tail heavy when loaded) so it stopped faster and straighter in panic stopping,

The weight on the front axle is not changed when the truck is loaded, the load is almost 100% on the rear bogie of the deuce, so are you saying that the front axle is loaded down when the FMTV is loaded?

....the LMTV also could cool better than the M35 (seems like a small item, but the M35 could not ever pass the TAACOM cooling system specs the LMTV had to deal with-those changes came from the overheating issues the Israeli's had wit htheir M35's in the '67 war).

That's very interesting since we are always commenting (complaining about?) on how cool the multifuel is running. I keep a more or less permanent radiator cover on mine and have operated the truck loaded all across the US, not desert heat though and never exceeded 205°F.... it usually stays below 180.
.......

 

[cranetruck]

....
However, automotive technology and understanding is not static. As more and more vehicle applications are built, those of us doing this job learn more about how to make a vehicle more effecient, less complex, easier to service, easier to drive, better handling, safer, stop quicker, etc. Knowledge is not static.....

How much of this would you say was incorporated into the desing of the 1969 Ford M656 series?
I have to ask since the xm757 is my new baby.
I also assume that all previous MVs must have been studied thoroughly by your group, so as not to reinvent all of it....then again perhaps when building to new specifications, it's best not to be biased....

What is a "high travel" leaf suspension?

 

[BobS]

Re: RE: Brand new FMTV spotted

....What's with the "No Step" on the bumper?....

Does not meet MIL-STD-1472E for clearance on the size 12W combat boot, so should not be used as a step.

Interesting response, makes me wonder about the constraints you had to work under.
It certainly would have made more sense to widen or placed the bumper a little further out since it would make an excellent step for reaching the windshield etc.

It also changes the meaning (at least by my understanding) of the "No Step" warning. Does it not usually mean that the marked area is not built to support a man's weight?

yep, we had some "restraints" to work with and around....

"NO STEP" means that it is simply unsafe, for various reasons, not just how heavy a soldier is.

 

[BobS]

RE: Re: RE: Brand new FMTV spotted

The automatic Trans had a little (very little) to do with the speed difference. The biggest difference was the combination of factors that lead to lower VCI- more suspension travel to prevent punishing the driver, improved jounce and rebound damping in the shocks front and rear, springs that were of a lower rate combined with front and rear anti-sway bars, improved tire cross section to increase traction for steering, braking, and terrain traversing, things like that.

The M35 we had was supplied by TAACOM and was "representative" of the majority of the fleet in 1984-it did not have the ISO bed (at that time there was a group within TAACOM saying ISO was not worth the extra cost). S&S, Teledyne, MVO, AMG (before they dropped out of the competition), and others all said TAACOM should keep the ISO bed, for obvious reasons, even at the increased cost.

The weight on the front axle of the M35 true-when it was designed, braking forces and vehicle dynamics were not as well understood as in 1984 (and more is understood now). What you mention is a liability in the safety of the truck, not a help. the more shift in the center of gravity (fore and aft) in the vehicle, the more unstable it is at the limits of it's handling. Remember, the M35 is not capable of the offroad speed of the FMTV (I do not mean just ours, but any of the competitor's vehicles). So, yes, the result is that part of the load is transferred to the front axle when the truck is loaded.

The Hercules engine (multifuel) never had to pass emissions either. FMTV was the first program that Congress had mandated had to meet emmissions standards for the year it was produced. The Israelis had to use and ambient temp of 140F plus 115F increase across the engine for heat rejection- giving a total engine out temp of 255F maximum. When White attempted to modify the multifuel to meet emissions, the engine failed miserably. I know this is going to anger a lot of people, but the multifuel engines, since inception, was a cluster@#$%. It was a poorly designed engine that had a BSFC of about 0.4lb/hp/hr fuel consumption, where even the noisy DDC 2 strokes were below that. It is also why the Herc could not cool itself-the radiator was designed to cool a much larger engine, due to the engine heat rejection. This is not to say that the Herc runs hot-it means that the Herc cannot stabilize it's temp at full loading without the oversized cooling system. And even this was not enough in the MidEast to do the job for the Israelis. I can explain in greater detail, but be aware-cooling is a VERY involved subject.

The result is that TAACOM decided a full diesel was required to increase milage, increase durability, and to increase the parts availability (since the Herc was not road legal for the US, TAACOM was the only buyer in the US and costs were astronomical).

The M656 was the beginning of the idea of FMTV, in that it explored the idea of "high mobility" through lower VCI (prior to the Ford work, it was though that the higher the ground pressure, the better the offroad mobility) and was the subject of much money between Ford and TAACOM. There is a standard design handbook (sorry-I don't have the number offhand) on automotive suspensions that was heavily modified by the results of that truck and it's increase over the M35. (Sidebar-this book is a result of all the TAACOM research into off and on road mobility since the invention of the auto-mobile (this is not a typo, I am using the hyphen in a specific manner of meaning a self propelled transport-the original meaning of the word "auto-mobile".)

Now that being said, Ford made several mistakes in the military application of the technology, but that is to be expected in determining how to employ new knowledge. I will not comment further, but suffice to say, Ford did a far more credible job on that, than later programs, especially when compaired to the M151 fiasco (they overlooked their own research when coming up with that abortion-yes, I lost friends in SEA to that POS. Let's leave it at that).

The M35 has,IIRC, 4 inches of jounce travel, metal to metal, and 4 inches of rebound travel to the max "droop" position. Our FMTV had leaf springs also (MVO management would not let me run air springs like the Teledyne- it was judged to be too great a technical risk in the tradeoff studies) that were tapered in 2 directions and were only 2 leaf, but could be overloaded higher than the M35 spring pack and still maintain 12 total inches of travel, instead of the 8 inches of the M35. The main difference was cost- one of our springs would have cost (on a per unit basis) twice what an M35 spring cost. TANSTAAFL.

 

[ptg530C]

Texas Euro-trash

 

[ptg530C]

I remember going to the SAE convention at COBO with my father and some of the emmissions suppliers seeing his TACCOM badge trying to sell him some of their services and him remarking "funny, we design these vehicles to kill people and we have to worry about them polluting the enviornment on the way".

 

[BobS]

Texas Euro-trash

????

Sorry, I don't understand your meaning-can you add to it? (Guess my brain is fading.... )

 

[ARMYMAN30YearsPlus]

Up Armored FMTV

Wow this is becomig a great education thread. Bob what would explain the damage to the frame on the FMTV I saw in Afgahistan if it is so robust? I am just curious because when the armor cab was added they also added huge coil springs to augment the leafs. Here are some picutes of the up armoring

 

[cranetruck]

Thanks Bob for that informative response! Lots of tidbits to research.

From my own rough calculations, based on horsepower and fuel consumption/hr the BSFC for the multi is about 0.38. Assuming that it takes about 100 HP to run the deuce at 50 MPH with a MPG of about 10.
That can be fine tuned and compared to other engines. I always felt that the hypercycle was more efficient....

Here are some googled numbers:

Engine Description Disp, Cu In HP RPM BSFC
Sultzer marine, max power 1,300,000 90,000 100 0.278
Sultzer Marine, max econ. 1,300,000 53,244 90 0.260
Stultzer Marine, overspeed 1,300,000 100,000 101.5 0.280 est
Caterpillar C18 1007 600 1600 0.352
Caterpillar 3126B-200 439 200 1550 0.340
Yanmar LV100 26.5 8.3 3600 0.459
MEP-531A 2 KW genny (yanmar) 12.9 4.2 3600 0.480

So, the multi roughly compares to a modern 1000 Hp engine in efficiency. If my numbers are not way off, I wouldn't say that's so bad....
I would also like to see the emission results. After several years, nobody has come up with real numbers.

 

[BobS]

RE: Up Armored FMTV

Without going into metallurgy specifics, there are 2 ways to increase the strength of a frame rail.

1. Add material (thickness, hieght of the section, width of the horizontal flanges, or "box" it in to provide another vertical wall)

2. Add strength by using a heat treatable steel

Both of these methods have pluses and minuses that the design engineer must balance against the program reqirements and costs. For example, adding thickness will cause:

Pluses- Reduced cost per pound of increase (only material cost and sometimes die cost to form the frame rail), increased stiffness in bending (vertical loading), increased stiffness in torsion (twisting loading on the rail), no special materials or processing needed

Minuses- Increase in weight per pound of increased stiffness. More material must be added per unit of increase than other methods.

Heat treating rail for increased stiffness:

Pluses- Does not substancially increase weight, allows a wide range of stiffness increase depending on the specific loading of a given component (this means that the crossmemmbers in the frame can be a different stiffness to allow a removal of stress concentration at anyy fasteners, providing a more uniform loading over all parts of the assembly).

Minuses- Increases costs substantially, due to special material, special processing, added assembly techniques, special fasteners, not repairale without substantial penalty of strength loss and further damage if not repaired correctly.

Now-remember I did NOT work on the S&S truck, so the following is ONLY a cursory look at those photos. No absolute conclusions can be drawn without a full analysis. My comments are only generally applicable!

In the pics you showed of the frame damage, it appears that the root cause was 2 fold, in that, the flange distortion surrounding the crack was caused by flexing of the rail at that point (a heat treated rail typically is "springy" and has a higher amount of distortion allowable, before failure), and finally, it exceeded it load in cycles, combined with the impact damange. The root cause of this would be the extra weight of the cab armouring and the terrain displacement of the axle (jounce bumper, specifically) and the reverse loading placed in the flange. Simply put, the axle hit the rail flange more than one time under the loading, indicating that the springs allowed the suspension to cycle beyond the flexing capabilities of the rail to support it for the same lifespan.

This is NOT to say S&S did anything wrong-they made do with what they had produced under the original specs from TAACOM and adapted as best they could, within the budget allotted for the armoured cab.

 

[ARMYMAN30YearsPlus]

RE: Up Armored FMTV

I know the tractor in the last picture is restricted from going more than five miles and hour without a trailer attached because they have flipped up on the nose with a even a moderate braking. We build several baskets of plate steel with a king pin in the center that they could load up to counterbalance the cab and make them highway roadable bobtails. I really apprcieate all you are bringing to the table I am learning a lot. Thanks

 

[BobS]

Re: RE: Up Armored FMTV

I know the tractor in the last picture is restricted from going more than five miles and hour without a trailer attached because they have flipped up on the nose with a even a moderate braking. We build several baskets of plate steel with a king pin in the center that they could load up to counterbalance the cab and make them highway roadable bobtails. I really apprcieate all you are bringing to the table I am learning a lot. Thanks

You are welcome-just remember what I said earlier. I am not anyone special-I know things from experience and have probably screwed up more tihngs than most. I just try not to let my mistakes out to the world....LOL.

 

[BobS]

Thanks Bob for that informative response! Lots of tidbits to research.

From my own rough calculations, based on horsepower and fuel consumption/hr the BSFC for the multi is about 0.38. Assuming that it takes about 100 HP to run the deuce at 50 MPH with a MPG of about 10.
That can be fine tuned and compared to other engines. I always felt that the hypercycle was more efficient....

Here are some googled numbers:

Engine Description Disp, Cu In HP RPM BSFC
Sultzer marine, max power 1,300,000 90,000 100 0.278
Sultzer Marine, max econ. 1,300,000 53,244 90 0.260
Stultzer Marine, overspeed 1,300,000 100,000 101.5 0.280 est
Caterpillar C18 1007 600 1600 0.352
Caterpillar 3126B-200 439 200 1550 0.340
Yanmar LV100 26.5 8.3 3600 0.459
MEP-531A 2 KW genny (yanmar) 12.9 4.2 3600 0.480

So, the multi roughly compares to a modern 1000 Hp engine in efficiency. If my numbers are not way off, I wouldn't say that's so bad....
I would also like to see the emission results. After several years, nobody has come up with real numbers.

A couple of questions:

1. Did you use J688 to obtain the road load calcs?

2. What grade input were you using?

3. What rpm are you calculating for?

Emmissions and how you perform the cleanup has a great effect on the BSFC. You won't find out the results of the original testing at White, unfortunately, due to the confidential nature of them (plus the fact that White has been out of the Herc building atage for a long time). For all practical purposes, the results simply do not exist anymore.

 

[Joaquin Suave]

Gosh what a great thread!!!

I've took on a design / development contract with an un-reasonable deadline (sound famillier Bob???), so I haven't followed this thread since last week. This is the real deal! Rare amoungst all the internet fluff.

I haven't nailed down an exact date for my "adventure vehicle swapmeet". However, when I do...I'll be sure to post it on SS.

How does Libby ride? Well, driving it from New York to California was one of my greatest adventures. Long, slow, loud, and turely a challenge given that the Allison computer would crap out EVERY time we downshifted into 3rd or come to a stop. It was the imputis for one of my greatest inventions...

The Libelua Cocktail! 3 Advils, 4 Alives, & 16oz Miller beer. We started our mornings ( at 5 AM) with a Libelula cocktail before a day of driving.

The Cover for the battery box is safely stashed in my backyard. I've had so many problems with the POS 12V/24V electrical system...I got tired of taking the cover on and off.

Here is a picture of me flex testing Libby so that I determine the peramters for designing the 3 point mounting of my camper box.

Here is an image of Libby's camper design

 

[cranetruck]

......
1. Did you use J688 to obtain the road load calcs?

2. What grade input were you using?

3. What rpm are you calculating for?

Emmissions and how you perform the cleanup has a great effect on the BSFC. You won't find out the results of the original testing at White, unfortunately, due to the confidential nature of them (plus the fact that White has been out of the Herc building atage for a long time). For all practical purposes, the results simply do not exist anymore.

Like I stated, rough calculations, but I now have a starting point, and sooner or later the real numbers will emerge, including brand new emission data on the old multifuel, they still run as good as ever and the data can still be obtained.
I based the power usage on the BTU value of the fuel and the approx efficiency of a diesel to get the horsepower.
RPM is directly related to the speed, which was about 50 MPH.

Your statements about the multifuel don't anger me, just a little irritating, I still love that engine. The 2-cycle DDC has a lot of fans also....
We don't need no stinking battery power to run our engines....or transmissions, for that matter.

Oh, JS, what you need for your travels is a good old deuce. LOL

 

[cranetruck]

Re: RE: Some more pictures of the FMTV

The big box behind the cab is the engine compartment-the radiator is on top,.....

Doesn't this create problems in rain and snow and how is the air flow into a horizontal radiator hehind the cab? Did you intend to have a cover for it?

 

[cranetruck]

Re: RE: Not all gone

http://www.expeditionportal.com/forum/showthread.php?t=13201

I do not know how many people would be interested, but Joaquin is having a get together in November at his place for expedition people. Perhaps there would be people here interested in attending. I will be making a small presentation about several subjects related to vehicle design, parameters and operations, using Libby as the training aid....

...

You may want to start a new thread on this.....