Eureka !
We were indeed the Dewoitine 520 and the Avia B135.
Both were good planes, which were on par with the Me109, but the production of the Dewoitine was not in gear before late 1939 and the Czechs never fought
.
Just a minor correction, the Bulgarians were indeed the intended users, the Bulgarian delegation first came to Czechoslovakia when it still existed (february 1939). The prototype was presented to the "Salon de l'aéronautique" in Brussels later that year, but at that time Czechoslovakia had become part of the Reich, hence the German markings. Bulgaria had ordered 12 planes, plus another batch of 50, but only the initial 12 ones were built.
As they never got the 20 mm cannon fitted, they served essentially as trainers.
Here are some links :
Dewoitine 520
another one (text only)
Looks like there is still one D520 flying
Avia B135 (in czech but w. pics)
The Bulgarian Avias (w. pics)
This being said, please accept my apologies if I contributed to kill this thread.
Archimedes, you have the floor, it is now up to you to decide if the show must go on, or if we let this old thread just fade away.