Nick I don't think anyone is questioning the time from first flight until enter service rather the time to develop up to the first flight . Do you have dates of the launch of each of these projects
Answering my own question
http://www.ainonline.com/Features/ne...aft02/s92.html
In the ever-so-slow world of rotorcraft development, that would mean the arrival of actual flying hardware 10 years after the S-92 “Helibus” (a term Sikorsky senior management is said to hate) was first announced at Heli-Expo 1992. After a further three years of market and design evaluation, the program was greenlighted.
http://www.flug-revue.rotor.com/FRTy...ack/NH90TR.htm
feasability study 1985
NH90 contract signed 1992
detail design 1993
first parts made 1994
First prototype 1995
# 2 1997
# 3 1998
# 4 1999
When I left Westlands in 1981 the EH101 workshare was already well established ( design work on WG34 dates back to the 70's )
Simple answer is , that large projects of this type move incredibly slowly , the added complication of having multiple design centres and cross border management make it even worse .