Forum: General F-22A Raptor forum

Just occured to me watching a Nova on JSF. Why was the JSF X-32 v X-35 but the fighter competition was YF-22 v YF-23? I know that X is experimental and YF is prototype figher, but what's the diff. I'm missing?

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Dunno. Was it maybe because the ATF prototypes were built with DoD funds (and hence the military designations) but the JSF prototypes were built with contractor funds? Shrug

X usually means Experimental Prototype whereas Y means Service Test.

http://www.designation-systems.net/usmi ... 16-401.pdf
Table A3.1. Description of Aircraft Status Prefix Symbols
Here's the whole document describing designations.
fisk

"The JSF Concept Demonstration Program is not meant to be a competitive fly-off. The Boeing JSF X-32 and Lockheed Martin JSF X-35 are not prototypes – they are technology demonstrators, hence the "X" designation, as opposed to the "Y" designation used for aircraft such as the YF-22 and the YF-23 (prototypes for the F-22). Both Boeing X-32 aircraft demonstrate how highly common variants of the same aircraft can be designed and built on a single product line."

From global security

Forum: General F-22A Raptor forum

X vs. Y