Let’s face it, I don’t think anyone reading EngineLabs DIDN’T have some kind of toy tank as a child. Whether it was a Matchbox-sized replica or a more advanced build-it-yourself model, or even an R/C toy, chances are there was a main battle tank mixed somewhere in your childhood possessions.

While you might think right off the bat, “What’s strange about a big diesel engine?” Well, read on (or watch the video) to see that in the quest to more efficiently move these hulking armored behemoths, there have been a number of different approaches tried in both modern and not-so-modern history.

Honeywell AGT1500

You might be familiar with the name Honeywell, as they have a lot of different lines of products, from pedestal fans like the one currently moving air around my office, to having a huge line of turbochargers (until recently) under the name brand “Garrett.” The AGT1500 is a turboshaft gas-turbine engine. While you might hear that and think of helicopter engines, you’d be right.

Turboshaft engines are the usual power source for modern helicopters, and there is even an aviation variant of the AGT1500. But we’re talking tanks, and the AGT1500 produces 1,500 horsepower at 3,000 rpm, and max torque of 3,950 lb-ft at only 1,000 rpm. Like most main battle tanks, the AGT1500 can run on a wide variety of fuels, such as gasoline, diesel, and jet fuel, in order to allow the M1 Abrams to operate on whatever is available, as tanks are often well in front of their supply lines.

The gas-turbine turboshaft engine of the M1 Abrams line of modern main battle tanks looks like it would be more at home in a modern helicopter than a 140,000-pound cannon on wheels, err, tracks. The 1,500-horsepower beast can propel the fighting machine to more than 45 miles per hour, if the governor was removed.

Guiberson 1020

Another tank engine that has an aircraft variant (you’ll notice that theme a lot here) is the Guiberson 1020. The T-1020 (T for Tank; the aircraft variant was the A-1020) was a diesel radial engine that powered the M3 Stuart light tank starting in 1941. However, the M3 was quickly upgraded to dual V8 engines in the M5 variant, not because the 1020 wasn’t capable, but rather because there was such demand during wartime for the radial engines in the aircraft configuration.

In its ground-based configuration, the 9-cylinder T-1020 displaced 1,021 cubic inches and made 250 horsepower at 2,150 rpm. It had an extremely low BMEP by today’s diesel engine standards, meaning it was wildly inefficient. However, it is quite a durable engine, still serving in its original role in some countries.

Detroit Diesel 6046

The General Motors 6046 engines were wild, in that they were a pair of inline 6-71 Detroit Diesel engines which weren’t turned into a V12, but rather a “U12” configuration, where the two inline sixes were placed side-by-side and mated to a shared output shaft. This unique engine was used in a number of tanks during World War II, but most notably, for us anyway, is in the A2 variant of the iconic M4 Sherman tank.

Obviously, being a twin 6-71 design, the 6046 displaced double that of a standard 6-71’s 426 cubes, for a stout 852 cid. The power numbers didn’t increase as linearly, with the engine putting out 4,10 horsepower and 1,000 lb-ft of torque. The 6046 is one of only two on this list without an aviation counterpart.

The GM 6046 is what they called a “U” engine. With two 6-71 Detroit Diesels situated vertically in parallel, they were joined to a single output shaft and run as a single unit. The U12 engine even went on to be further developed as a quadruple 6-71 setup.

Rolls-Royce Meteor

This one might be our favorite on the list, largely because it is the tank variant of the historic Merlin engine which powered the legendary P-51 Mustang, Hawker Hurricane, and Supermarine Spitfire fighter planes, among others. Like the Merlin, the Meteor engine is a V12 configuration with a 5.400-inch bore and 6.000-inch stroke for 1,649 cubic-inches of displacement.

While the Meteor engines were largely rebuilt Merlin III engines, the Meteor’s power production was quite different, producing 600 horsepower at 2,400 rpm and 1,450 lb-ft of torque (compared to the Merlin III’s 1,030 horsepower at 6.5psi of boost). Interestingly, the Meteor has come back into minor notoriety lately as the photos of the “Meteor Interceptor” project have started to make their round, which a team of Swedes has fit the engine into a Ford Crown Victoria Police Interceptor.

Ford GAA Engine

The Ford GAA engine is the other engine on this list that has no aviation variant, although it was originally designed to be an aircraft engine, based on the Merlin’s bore and stroke, however, it never got off the ground (no pun intended). Instead, Ford took the all-aluminum, four-valve-per-cylinder dual overhead cam engine and lopped four cylinders off the end of it, making a 60-degree V8 engine they dubbed the GAA.

Making 500 horsepower at 2,600 rpm, and 1,050 lb-ft of torque at 2,200 rpm naturally aspirated on gasoline out of “only” 1,094 cubic-inches, the GAA was fitted to the later variants of the M4 Sherman, M7, and M10 tanks. Like the Meteor, there is an internet-famous 1970 Mustang with a GAA engine sticking out of the hood.

The Wright R-1820 was a prolific aircraft engine in its day, powering a number of legendary fixed-wing and rotor-wing aircraft. It was put into tanks in both the standard gasoline version as well as a diesel variant.

Wright R-1820

Like the Meteor, the Wright R-1820 9-cylinder radial has been built by a number of engine manufacturers under license. While it has powered many famous aircraft, like the DC-1, DC-2, DC-3, B-17, SBD Dauntless, and even the H-21 and H-34 helicopters, we’re talking tanks here. The gasoline-powered variant was used in some armored vehicles, but for tanks, a diesel variant — the D-200 — was developed.

Caterpillar Inc. developed the diesel variant of the engine during World War II, producing half of the G-200’s (gasoline-powered ground-based variant) 900 horsepower at 2,300 rpm, with the D-200 producing only 450 horsepower at 2,000 rpm.