When Allied Signal wanted to develop a flying test bed to perform in flight testing of various engines Soloy was selected to accomplish the modification to their Boeing 720.  Since its completion Honeywell (Allied Signal) has successfully tested at least 8 new engine designs and has accumulated approximately 500 hours of trouble free in flight testing.

The Honeywell Boeing 720 Flying Test Bed was modified at the Soloy Aviation Solutions Olympia facilities.