Addendum to Nomad history
The Allison 250 actually began its life in 1957 as a result of a US Army contest to provide power for a Light Observation Aircraft (LOA) in two versions, turboprop (fixed wing) and turboshaft (helo). The Army decided only to get LOHs with the turboshaft, and the Allison 250 B15C was first used in the Italian SIAI-Marchetti SM1019E first flown in 1969.
The sad loss of the Nomad at Avalon was caused by an elevator anti flutter strip being devised, attached and test flown without supporting wind tunnel tests. The test flight was done on a windy day - 30 knots plus down the strip.
Immediately after liftoff it became apparent that the aircraft was barely controllable in pitch. The PIC elected to turn downwind and lost control in that manoeuvre. The acft crashed with a tailwind of 35kts plus.