Niilo and Valto Karhumäki started in autumn 1924 the construction of an airplane at their home. The work also involved Emil Kankaanpää and Hope Hovinen. The machine was given the name Bear 1.
The brothers built in the 1920s of four aircraft: Bear 1 Bear 2 Bear 3 and Tern. Construction was initially something of a hobby, but soon expanded into a versatile aviation business.