VL Pyörremyrsky began when the Air Force ordered two new Finnish fighters into design phase: VL Pyörremyrsky and VL Puuska. The design was given following basic parameters:
- At least 50 km/h faster then the fastest enemy bomber
- If it is faster than enemy fighters, it may be less agile and worse climber
- If it is slower than enemy fighters, it must be better climber and more agile
Pyörremyrsky had larger wing than Me 109, so it was better in turning combat, but hence slower than the Me 109 G.
First Me 109 Gs arrived to Finland in March 1943, so the test flight results were used in the continued design of Pyörremyrsky. Notice that its design had been already started before Me 109s arrived,. In Autumm 1943 the State Aircraft Factory offered five different Pyörremyrsky variants for production: PM-1 to PM-5, plus the subvariants PM4-a and PM-4b and PM-6.
Of those two were chosen for further design, with names Puuska and Pyörremyrsky. Puuska was to be a light weight, very agile, fast, excellent climber - with no armor and one cannon, with possible two machine guns on wings.
Puuska's design and prototype construction were cancelled though.
One example of Pyörremyrsky was built.
VL Pyörremyrsky had DB-605 AC engine with 1475 hp, one 20 mm cannon, two 12,7 mm LKK 42 machineguns. Top speed on sea level 522 km / h, 620 km/h at 6400 meters. Flight time 1h50mins with normal fuel, plus two extra fuel tanks could be carried on wings.
When Pyörremyrsky test flights began it was found to be more agile than the Me 109 G and easier to fly, but war had already ended for Finland and the Air Force had enough Me 109 fighters for peace time rquirements, so the development was cancelled.
