[1][2][3][4] Experimentation with the XM-1 lead to the final configuration of the later Marske Pioneer.

The aircraft went through several versions, each a modification of the same basic airframe as Marske experimented with configurations.

[1][4] The XM-1 was built with a welded steel tube fuselage covered in fiberglass.

It was registered with the US Federal Aviation Administration in the Experimental - Amateur-built category.

[1][2] Data from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II[5]General characteristics Performance