[TalonDJ]

“During WW II, we could design, manufacture, and field weapons with alarming speed.”

A zeal that cost the lives of many test pilots.

“For example, the P-51 went from drawing on a napkin to a flying prototype in 102 days.”
People love throwing that number around but forget that it took YEARS longer before the design was perfected.

The complexity different between a P-51 and an F-22 is several orders of magnitude.

[AndyJackson]

And do not forget that North American originally fielded it with the Allison engine. It was the Brits who recognized that it was a superior airframe and would be a top notch high-altitude fighter if they used the Rolls-Royce Merlin engine.

[SkyPilot]

You make precisely my point - the complexity of today's weapon systems means that we have to be planning for war now. We cannot do so on the fly. The Russians and Chinese have spent the last decade rearming, while we have been going in the opposite direction since around 2007. The 102 days number is historically accurate, and the prototype was the essential aircraft. And as Andy mentioned, they refitted one with a Merlin engine (from the Allison non-supercharged one). That took only a few weeks, and in only one flight they realized the benefits and started the transformation on models almost immediately. Can you imagine that happening today? No. It would take 5 years for even a technological equivalent test to even occur.