You might also realize that I get your point. If someone builds a 36L engine producing 860 hp. with room for a gun, that's a good idea. If someone else builds a 26L engine producing 1,030 hp, but it doesn't take a cannon, that's also a good idea. If someone builds a 34L engine with 1100 hp, and the available cannon doesn't work until the BoB is over, that's not that good of an idea. The Yak-9T was perhaps the most stellar performer in this regard, except that the cannon wrecked the a/c. None of this helps Poland, which should have developed indigenous industries to produce undercarriage, propeller, hydraulics, and aero engines, as well as myriad other products, and done it much sooner so we wouldn't have to discuss how they couldn't have what they needed when they needed it because nobody else could have supplied it either, except maybe Germany,at that critical moment.