WE DONT HAVE WIND TUNNELS
AND WE ARE DEVELOPING 3 JETs simultaneously
Having wind tunnels is not enough.
How many? What type? What scale? How many hours they already run? These are the key questions!
Question 1&2: To develop a jet, you need at least over 30 different kind wind tunnels: different speed, different weather condition, etc, etc.
Question 3: What size of model can be tested? How long can continue? What kind of data can be collected?
Question 4: Aerodynamic design is based on experience and data accumulated. That is why USA and Russia are the leading countries on this area, both of them have the largest wind groups in the world and longest operation hours in the world.
We can look at Japan as an example: she has some of the best wind tunnels in the world. But just look at how they are struggling with their 5th generation jet.