3-engine Cordership is a c/12 diagonal spaceship that was discovered by Paul Tooke on January 12, 2004. Until the 2-engine Cordership was found, it was the Cordership that used the fewest number of known possible switch engines. Despite this, the 4-engine Cordership is smaller in terms of minimum population (the 2-engine Cordership beating both).
David Bell discovered in 2005 that the 3-engine Cordership can be used to turn a lightweight spaceship 90 degrees as shown below. It could be  constructed with 15 gliders, and Tooke created a gun for this spaceship only a week after its original construction (see 3-engine Cordership gun). In March 2017 Luka Okanishi discovered a three-glider synthesis for a switch engine, which reduced the recipe to only 11 gliders.
The 3-engine Cordership can easily be destroyed by three
eater 1s and four blocks, as shown below. This cleanup reaction was found by Jason Summers.
On September 15, 2020,
wwei23 discovered several variant 3-engine Corderships, including one that cleans up its trailing blocks with sideways gliders, similar to a 5-, 6-, or 7-in-a-row Cordership.
Dave Greene discovered a glider synthesis for upgrading a switch engine to a wing, which can be repeated to form the complete Cordership. Adam P. Goucher then built a Herschel conduit to convert a glider into a 3-engine Cordership.
3-engine Cordership about to reflect a lightweight spaceship by 90 degrees (click above to open LifeViewer) RLE: here Plaintext: here
149P96H8V8.1 at Heinrich Koenig's Game of Life Object Catalogs