I am starting a small series on the "odd variants" of some aircraft types. This is the first post ๐ Please upvote if you would like to see more โ๏ธ
Honeywell owns a 757-200 with RR-engines. They have fitted their 757 with a small, 3rd, wing to test avionics, engines and other instruments. So far it has carried a jet engine, prop engine and instruments..
It is an early 757 from 1983: the 5th delivered 757. Delivered to the now defunct Eastern Airlines. Honeywell aquired it in 2005 as N757HW.
Picture source // aeroprints.com