M1 Abrams gas turbine engine question.

koxinga

Well-Known Member
That's right, the M1 ran better on DF-2.
If the M1 ran better on DF-2, why did the US Army switch to JP-8? They were coming off the M60 which was using DF-2 and because of the M1, the supply chain had to accomodate another fuel type.

The only reason that I can think of is the performance outweight the fuel economy and that fitted with US CONOPS.

Then the larger question is not whether the M1 can run on DF-2/vodka/sunflower seed oil, but whether the tradeoffs are acceptable in the Ukraine's context. It appears the answer is yes for now, although I remain interested in the considerations.
 

Pukovnik7

Member
If the M1 ran better on DF-2, why did the US Army switch to JP-8? They were coming off the M60 which was using DF-2 and because of the M1, the supply chain had to accomodate another fuel type.
JP-8 is used by aircraft, fixed-wing and helicopters alike, so both USAF and US Army had to handle absolutely enormous quantities of the stuff anyway. So while DF-2 may have been better for the M1 on its own, keep in mind that US military is an expeditionary force and has access to large quantities of fuel. Using JP-8 was simply easier from the logistical standpoint.
 

Rob c

The Bunker Group
Verified Defense Pro
JP-8 is used by aircraft, fixed-wing and helicopters alike, so both USAF and US Army had to handle absolutely enormous quantities of the stuff anyway. So while DF-2 may have been better for the M1 on its own, keep in mind that US military is an expeditionary force and has access to large quantities of fuel. Using JP-8 was simply easier from the logistical standpoint.
.

JP8 has a slightly lower S.G. than some other military fuels and when we used it our aircraft got a slight reduction in range from what we were use to with our regular fuel which was F34. (similar to JP4) Weight wise we could only fit 10800 lbs in an A4 of JP8 as apposed to 11400lbs of F34. The mass weight being the important factor, not the volume. Otherwise performance was the same.
 

FormerDirtDart

Well-Known Member
JP-8 is used by aircraft, fixed-wing and helicopters alike, so both USAF and US Army had to handle absolutely enormous quantities of the stuff anyway. So while DF-2 may have been better for the M1 on its own, keep in mind that US military is an expeditionary force and has access to large quantities of fuel. Using JP-8 was simply easier from the logistical standpoint.
When the US Army transitioned their ground tactical vehicle fleet and support equipment to JP-8 they also transitioned their aviation fleet from JP-4 to JP-8
So, it was a massive reduction in logistical efforts across an organization the size of the 80's/90's US Army
 

Takao

The Bunker Group
You also have to remember, the US Army runs more helicopters than most countries have trucks. No idea on reliability or if they mean US military or US Army, but they could have over 5000 of the buggers. When you are throwing attack helicopter Brigades into the mix, their fuel becomes supper important. And the reality is, even an Armoured Brigade's fuel usage pales into insignificance when compared to an Aviation Brigade. It makes sense to hence run everyone on JP-8. For a more, 'normal' Army like Australia, we can't do that. Even on a perfect day, we are throwing a Regt/Bn of helicopters into the mix. Against an Armoured Brigade, the 'need' for jet fuel is much, much lower. So we just stick with diesel.

People also need to be careful at comparing like for like. A M1 chews fuel like ... well, like I chew chocolate. An M1A2 on the other hand, it's much more restrained. The work done over the years to improve the efficiency of the AGT1500 (TIGER ECU update in 2006 improved consumption by 10% straight up for example) and add an APU means there is no real difference in fuel consumption between Western MBT. And I say real, because fighting isn't just drive at optimal rpm over nice terrain. It's also not until you are dry. All our MBTs are about the same weight, they are all about the same in performance. Physics demands that they all chew about the same amount of fuel. As a neat fact, a Pl of M1 chews as much fuel as a Pl of M4, despite 60 odd years difference....

Anyone who thinks that supporting Leo 2's is easy....probably shouldn't be listened to..... ;)
 

Pukovnik7

Member
People also need to be careful at comparing like for like. A M1 chews fuel like ... well, like I chew chocolate. An M1A2 on the other hand, it's much more restrained. The work done over the years to improve the efficiency of the AGT1500 (TIGER ECU update in 2006 improved consumption by 10% straight up for example) and add an APU means there is no real difference in fuel consumption between Western MBT. And I say real, because fighting isn't just drive at optimal rpm over nice terrain. It's also not until you are dry. All our MBTs are about the same weight, they are all about the same in performance. Physics demands that they all chew about the same amount of fuel. As a neat fact, a Pl of M1 chews as much fuel as a Pl of M4, despite 60 odd years difference....
How did they solve the "crawling" issue? From what I know, turbine tend(ed) to go through fuel far more quickly than diesel engine because it is most efficient at maximum RPM, and thus far less efficient than diesel when:
1) tank is idling
2) tank is "crawling" along at low speed

I believe they solved the idling issue with APU, but what about low-speed movement?
 

FormerDirtDart

Well-Known Member
How did they solve the "crawling" issue? From what I know, turbine tend(ed) to go through fuel far more quickly than diesel engine because it is most efficient at maximum RPM, and thus far less efficient than diesel when:
1) tank is idling
2) tank is "crawling" along at low speed

I believe they solved the idling issue with APU, but what about low-speed movement?
No, the APU is not connected to the powertrain, it just provides electrical power allowing the turbine to be shut down rather than idling. It was installed to replace a significantly heavier battery pack which was no longer sufficient to provide for modern power needs.
That is one of the goals hoped for in installing electric drives in tactical vehicles. The ability move short distance under just battery power, without the noise signature of the vehicle's main engine
 
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