Here is an interesting SP write up on the M-1 Tank.
So much is sad about the M-1 but the whole power-pack thing only has one path: to get worse with less available motors.
The reduction will remove 24 M1 companies leaving 952 M1 tanks in service.
Remember, we have a tank factory yet there are no "new" M-1s. Only those pulled from storage. Be nice someday if we were building the right kind of tank.
Read page 4 of the comments and look for what Blacktail wrote:
Blacktail 6/14/2014 6:49:11 AM
There's a lot that needs to be clarified here --- first, regarding the content of the article.
It was stated that;
"The army has already invested several hundred million to develop an easier to maintain engine; the LV100-5. This engine has 43 percent fewer parts and requires less than half as much maintenance. It is smaller, lighter, quieter and emits no visible exhaust. But it will cost several billion dollars to put into production."
The LV100 is the only tank engine around that's worse than the AGT1500, and this is why;
- The new LV100 gas Turbine would only reduce fuel consumption by 33% --- it would still consume 3 to 6 times as much as a Diesel engine.
- That the US military expects the LV100 to be 50% more efficient at idle means the M1 would consume all it's fuel in 16 hours, while all Diesel tanks (which have HALF the M1's fuel capacity) can idle for more than 48 hours on end.
- The 30% reduction in Mean Time Between Failure of the LV100 from the AGT1500 is an increase in operability to only 26 minutes.
- The AGT1500 costs $200000 --- more than TEN times the price of an equal-power Piston engine.
- A single LV100 engine would have cost more than $800000.
- The LV100 was also supposed to be quieter and cooler than an AGT1500, but these promises are also meaningless --- it's STILL a beacon for IR sensors (with an exhaust temperature of over 1700 degrees!), producing exhaust STILL several-times as hot as Diesel, and it STILL fails to muffle the noise generated by the rest of the tank.
- It still runs ceaselessly at 30000rpm (which is mechanically-reduced to 3000rpm at the driveshaft, to avoid braking it), resulting in fuel consumption that's much higher at low speeds, because the consumption rate is constant. This is why an M1A1 is capable of driving 298 miles at 40mph, consuming 2 gallons/mile in the process, while moving at a 15mpg "marching" speed (the speed tanks most often move at) results in 8 gallons/mile of fuel consumption --- and why Gas Turbines consume fuel so quickly at idle.
- The last mention of the LV100 by the manufacturer was more than a decade ago; meaning, the project is extinct.
"A diesel engine has been proposed but these are twice as heavy, take up more space and produce less power."
It only appears this way, because the AGT1500 is never compared by it's manufacturer and users (who form the two halves of it's marketing effort) with substantial amounts of heavy equipment always fitted to the powerpack when the M1 operational. For example, the aft fuel cells in the M1 Abrams FOV are *part of the powerpack* --- the weight of these is always subtracted from the powerpack's total weight whenever the AGT1500's apologists promote it.Because the M1's AGT1500 Gas Turbine engine is so fuel-hungry, the M1 was stuffed so full of fuel cells, that it's engine was literally encased with them. Incidentally, this also means that when one of these cells ruptures, a Tank Fire begins that WILL completely destroy an M1, because it can't be put-out.
"All those additional M1 tanks are there if there is a major war."
There are no engines to power them. The AGT1500's production ended in the late 1990s, and many of them are burned-out beyond repair. Those that are usable are the only reason the US Army's sad, dying little tank fleet hasn't already long-since been scrapped.
Quote Reply
Blacktail 6/14/2014 7:10:54 AM
Now, for a few of the comments made by the readers...
HR;
"The engine is what makes M1 very much unique among tanks. It has been known from the start that it is a tradeoff. Quick acceleration vs. fuel consumption and reliability."
This has never been true. When the M1 Abrams was introduced, crews operating them for the first time who had driven Diesel powered AFVs complained about how poor it's pick-up was, despite it's high power/weight ratio (the highest of any M1 Abrams variant, ever, at over 22hp/ton). This was also the most common complaint by consumers during product testing of turbine-powered automobiles. The reason is that Gas Turbines have extremely weak low-end torque, which is largely because they run so fast.
The AGT1500 runs ceaselessly (except when starting or shutting-down) at 30000rpm, which is reduced to 3000rpm at the driveshaft. The significance of that is that when an engine runs at higher rpms to produce a given maximum quantity of power, it produces less torque than engines that run slower when producing the same amount of power. Torque is a big deal, because it govern's a tank's acceleration, towing potential, and slope-climbing capability. You can measure an engine's torque by multiplying it's horsepower by 5252, then dividing the result by the number of rpms the engine produces it's full power at. The result is it's torque, measured in pound-feet. Multiply 1500hp by 5252 and divide the result by 3000, and you get a disappointing 2626lb/ft. By contrast, the MTU 883 that powers the Leopard 2 produces 1500hp at 2600rpm; the result is 3030lb/ft of torque. That's 13% less torque than the MTU 883 --- and the worst of any tank engine in the 1500hp class.
HR;
"The Leopard II is a full generation ahead of the M1, so it stands to reason that it will be improved."
Don't bet on it. The same organization that would improve it (the US Army and Defense Industry) are the ones who let the M1 fall behind to begin with.
trenchsol;
"120mm smoothbore gun can hit the enemy tank at more than 3 miles."
The gunnery computer for the M256 only computes ranges to 4000m, which is about 2 miles. You can't confirm a kill beyond that distance in an M1.
trenchsol;
"Muzzle velocity is 1500 - 2000 m/s. How does maneuvering help against that ?"
There's no time to react to a projectile that fast, but evasive maneuvers are also used proactively. Ever try to hit an erratically-moving target at a long distance? It' not easy at all.
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