There’s One Main Reason Ukraine Might Prefer German Tanks Over U.S. Tanks—The American Vehicles Guzzle Gas

Pressure is mounting on the German government to sign off on various European countries’ proposals to donate German-made Leopard 2 tanks to Ukraine.

But German officials, clearly desperate to avoid the appearance of arming Ukraine for offensive action, told The Wall Street Journal they wouldn’t approve the Leopard 2s unless U.S. officials agreed to give Ukraine some of America’s own M-1 tanks.

Think of the U.S. tanks as diplomatic cover for the Germans.

There’s one good reason the Ukrainians would prefer Leopard 2s over M-1s, however. The M-1 has a gas-turbine engine rather than a strictly diesel engine like almost every other armored vehicle has—and that includes the Leopard 2.

In essence, the M-1 is meant to burn jet fuel, and not very efficiently. That can complicate the logistics of any army that operates the type.

When the U.S. Army and Chrysler—later, General Dynamics—designed the M-1 back in the 1970s, they included the 1,500-horsepower gas-turbine in order to lend the tank high acceleration and speed without also weighing it down too much.

Thus the M-1, which in its latest version weighs more than 70 tons, is fast—with a top safe speed of around 45 miles per hour while burning JP-8 aviation fuel. The Leopard 2 also weighs 70 tons, but with its 1,500-horsepower diesel engine might be slightly more sluggish and a few miles per hour slower under some conditions.

The M-1’s modest agility advantage over similar tanks comes at a cost, however. The American tank gulps fuel faster than most tanks do. In one 1990 study, the Washington, D.C. Project on Government Oversight concluded an M-1 would burn 83-percent more fuel than a Leopard 2 would do at the same speed.

That high fuel consumption weighs on an army’s logistics. A U.S. Army unit mixing M-1s with other vehicle types—M-2 fighting vehicles, for instance—needs at least two separate fuel trains. One for JP-8. One for diesel.

And the combined capacity of the logistical trains must increase. According to POGO, when a U.S. Army battalion traded its old diesel M-60s for M-1s, it also had to add several dozen fuel tankers, trailers and pumps in order to keep the new tanks gassed up over the same distance as before.

When the Germans ask the Americans to give the Ukrainians M-1s as a precondition for Germany signing off on Leopard 2s, the Germans in effect are demanding the Ukrainians accept the extra logistical burden that comes with the American tanks.

There’s one way somewhat to simplify the problem. The M-1’s Honeywell gas-turbine in theory can burn any fuel that’s thin enough to move through its lines. The U.S. Army prefers JP-8, but another army could top off its M-1s with diesel, motor gasoline, kerosene, moonshine, whatever.

It’s unclear whether and how much changing the fuel alters the tank’s performance. The Australian army fuels its M-1s with diesel and hasn’t reported any serious performance issues.

But force-feeding the M-1 diesel doesn’t do anything to quench the tank’s extreme thirst. Whatever fuel it burns, the M-1 is going to burn a lot of it.

Would the Ukrainians say no to thirsty American M-1s? Almost certainly not. But Leopards 2s with their simpler and lighter logistics probably are better for a small-ish, middle-income country fighting an existential war against a much bigger foe.

German officials might bear that in mind as they weigh whether, and under what conditions, to approve tanks for Ukraine.