The 311 is a printer that uses type wheels with their characters on the wheel's rim parallel to the shaft. As Dave said, there is a line width worth of type wheels mounted in parallel. The wheels spin on the back side of the paper. A hammer on a linear track runs across the front to impress the character through a ribbon. Pictures attached of machine and two type wheels.

The other drum printer I am familiar with is the UGC-74. Unlike this one, the lines of characters are a spiral, and there are individual hammers for each column.

The 311 as the AN/FGC - 80 version is in the 1970 KL catalog on page 4. A scan of the catalog may be downloaded at:

Kleinschmidt used Smith Corona type baskets and keyboard keys from the founding of Kleinschmidt Laboratories in 1948. Smith Corona bought KL in 1956. After merging with Marchant the name and logo change became SCM. SCM went on to become a diversified conglomerate including Glidden paint. SCM was sold to Hanson in the UK in 1980. Hanson spun off all operations with less than $20mm in annual revenue. KL was bought by its then general manager. As Kleinschmidt Inc they still provide EDI services, a spinoff of there old rail car tracking business.

I wonder if Glidden provided paint for Smith Corona, even though we had a very active paint maker, Strathmore here in Syracuse. The paint booths and drying ovens were largely intact in the factory building when it was flattened. ATTACHED is a photo of an SCM mechanical calculator, restyled from the older Marchant Figuremaster and Figurematic models. I am trying to find one of them as well. I have no idea who the designer was, but the general theme was used for years on many SCM products.