The current milestone for first hover flight of this aircraft, taken from the AHS calendar is July 14 1954. An alternative source (Journal of the AHS, Vol. 1, No. 1, page 57) states that this was actually the first hover flight of the second prototype. This source states that the first flight of the first prototype was February 11 1954. It also states the aircraft name as 'Convertiplane' not 'Convertaplane'.

Can anyone clarify which of these 2 sources provides the definitive information?
* Last updated by: comodo15 on 7/14/2016 @ 9:32 AM *

“My research says the first lift off of ship #1 was Feb. 1954 (see page A-134) Keep in mind the first liftoff followed by nearly an immediate landing may (sometimes) hardly qualify as the first flight to many people.”
Franklin D. Harris, author of Autogyros, Helicopters and Other V/STOL Aircraft
AHS Member since 1960

Transcribed by AHS staff Betty Chen
* Last updated by: VertipediaTeam on 8/19/2016 @ 9:21 AM *

The AHS Calendar entry for July 2013 seems to fully support your response and the milestone has been changed in accord.