Skeleton Tank preserved at Aberdeen Proving Ground
|Place of origin||USA|
|Manufacturer||Pioneer Tractor Company|
|Mass||18,000 lb (8,200 kg)|
|Length||25 ft (7.6 m)|
|Width||8 ft 5 in (2.57 m)|
|Height||9 ft 6 in (2.90 m)|
|1 X .30 caliber machine gun|
|Engine||2 X Beaver 4 cylinder|
|Suspension||Rigid frame tracks|
The Skeleton Tank was an experimental prototype tank built in 1918 by the Pioneer Tractor Company, Winona, Minnesota for $15,000 ($ 249,900 in 2019).  Prototype was ready for trials by October of 1918. Designed with several innovative features, some of which were controversial at the time, the Skeleton Tank project did not proceed beyond the single prototype tank.
The objective of this prototype was to develop a lightweight vehicle capable of crossing wide trenches in a manner similar to the then-conventional heavy British tanks. Unlike the British tanks with their fully enclosed chassis, the Skeleton Tank achieved the requisite lozenge shape by supporting its tracks with a skeleton-like framework formed from ordinary iron pipes joined by standard plumbing connections. Suspended between these track frames was an armored fighting compartment carrying a machine gun turret. The engines were also housed in this armor-protected box.
This arrangement dramatically reduced the weight of the vehicle as compared to the larger British and French tanks while preserving the trench-crossing capabilities of those machines, and there was a belief that most enemy bullets and cannon rounds would pass harmlessly through the structure. However, it eliminated the possibility of mounting weapons in sponsons as in the British tanks and thus limited the armament that could be carried.
It was 25 feet long, which compared favorably in trench-crossing potential to the then-standard heavy British Mk IV and Mk V tanks with lengths of 26’5” but weights of 28 to 29 tons, and the French Schneider CA1 and Char d'Assault St. Chamond with lengths of 19'9" and 28'11" and weights of 13.5 and 23 tons respectively.
It was 8’5” wide, narrower than the 10’ to 12’5” of the British tanks, and slightly higher at 9’6” vice 8’8” for the Mk IV/V due to its turret.
It was never ordered into production.
- Chamberlain, Peter; Ellis, Chris (1972) . Pictorial history of Tanks of the World 1915-1945. Galahad Books. p. 167. ISBN 0-88365-183-1.
- Moore, Craig (2017). Tank Hunter: World War One. The History Press. ISBN 9780750986595. - Total pages: 240
- Zaloga, Steven J. (2017). Early US Armor: Tanks 1916–40. Bloomsbury Publishing. ISBN 9781472818089. - Total pages: 48