aircraft/loadouts VL Myrsky

LunarRainbow · September 2, 2016

History of the Myrsky: The VL Myrsky (Myrsky = Storm) was an attempt of the Valtion Lentokonetehdas (VL) to build a more modern plane, an assignment given by the Finnish government because they had trouble purchasing modern planes from other countries because of the tension in the late 1930s. VL got the assignment in the spring of 1939, but the VL had already made sketches of the Myrsky in 1938.

The initial specification for the fighter wasn't precise, they wanted a fast fighter, capable of air superiority and strafing. It was to be built with wooden wings and a welded tube frame.

Arvo Ylinen (technical director of VL) made a preliminary proposal of the fighter in 4.5.1939 (day-month-year). It was to be a low-wing monoplane with a retractable landing gear (all three). Wingspan: 11.2 m. and a wing-area of 18.0 m². Top speed: 555 km/h at 4725 m. climb rate: to 5 km in 6 min and 35 s. Armament: 2x13 mm and 2x7.7 mm in the wings. These plans were changed and there were multiple engines proposed which i'll leave out from this post. MY-1(2).jpg

The planes designing was halted because of the Winter War. The first prototype was ordered in 20.12.1940, but in early 1941, VL made changes to the specification (smaller wing-area for more speed and 550 l of fuel etc.). The first flight was in 23.12.1941. (identification number MY-1). The flight showed some major problems with the aircraft. Like it had a tendency to turn to the left and bad cooling for the engine. The MY-1 went through 4 stages to overcome these problems.

In the spring of 1942, Finland changed their vision of the Myrsky's purpose, now it needed to be a pure air superiority fighter. Because of this, planes MY-2 to MY-4 were build. Known as the I series (test series), they were structurally different from each other. These three planes were all destroyed in accidents.

The II series (big series) of planes (MY-5 to MY-51) were the last. In this series, they fixed what they thought caused the crashes of MY-2, MY-3, and MY-4. The real reason was found in 1944 with MY-5 and MY-6 and were mostly fixed. The MY-5 first flew in 21.12.1943 and MY-6 in 2.2.1944.

The first squadron to get the Myrsky was TLeLV 12, this was a reconnaissance squadron. The fighter squadrons had Bf 109s so they weren't interested in the Myrsky.

The Myrsky served in the Finnish Air Force (not counting prototypes and test flights) from 23 February 1944, to 9 May 1947 when a Myrsky broke apart in a dive. It got immediately banned from flying. The last flight was in 10 February 1948 when Ilmavoimien varikon Koelentue got a special permission to fly the MY-50 from Kauhava to Tampere. Landing to Tampere, the pilot forgot to lower the flaps, leading to the plane not stopping before the end of the runway. MY-50 broke it's left gear and propeller.

The plane that i want is from the II series, therefore i'll put their performance.

Statistics/equipment:

Engine: Pratt & Whitney R-1830 SC3-G "Twin Wasp" 14-cylinder, supercharged, two-row, radial engine.

Engine power: Take-off power 1065 hp (2700 rpm) for 5 min. Max. 910 hp (2550 rpm) for unlimited amount of time. The critical altitude is at two different altitudes, take-off power has critical altitude at 2650 m and cruising power has at 3650 m. As i've understood it.

Propeller data: VLS 8002 constant speed propeller with a propeller governor and a copied Hamilton Standard propeller hub. Blade is made out of kolupuu, a.k.a. koivuvaneriviilupuu. I don't have a translation, but it's made out of thin layers of birch that are glued together in high temperature/pressure. The propeller pitch can be adjusted by 20 degrees.

Armament: 4 x 12.7 mm VKT 12,70 LKk/42 in the engine cowling. 260 rpg for the two outer guns and 220 rpg for the two inner guns. RPM is 1 100 rounds without synchronization.

Payload: 2 x 100 kg, or less, bombs.

Take-off: When the speed is 165 km/h it will take-off, and no flaps are used. Take off run is ca. 300 m.

Weight: Empty is 2485 kg, full load (fuel, oil, ammunition and pilot) 2950 kg. Max. weight is 3213 kg.

Top speed: (weight is 2850 kg, test flight with the MY-6) At sea level 470 km/h, and at 3300 m it's 515 km/h. It says in the book "which is 10-20 km/h slower then what was achieved earlier with the test series planes. The manual gives a top speed of 535 km/h with a 3% tolerance (radiator closed). Radiator open, slows the plane down approx. 8-10 km/h."

Climb rate: At sea level 15 m/s (Best climbing speed is 240 km/h IAS at sea level. After you've passed 1 km you start lowering the speed by 5 km/h for every kilometer you've passed). This is data from the MY-6's test flight. Manual data shows a little higher climb rate at full power. Weight 2850 kg.

Ceiling: 9500 m according to the manual, but 8600 m with a test flight with the MY-6, which was lower then with the other tests.

Turn time: 18 s at 2 km if the starting speed is 440 km/h and finishing speed is 350 km/h

Stalling speed: Gears/flaps up it's 170 km/h IAS, and gears/flaps down it's 150 km/h.

Gear: Gear up takes 30 s, gear down takes 20 s. Below 250 km/h you can take the gears down.

Flaps: Flaps down takes 10 s. Below 240 km/h you can lower the flaps to landing position.

Oil Radiator and Radiator: Controllable.

Brake power: Satisfying at it's best.

Fuel tank: 300 l, made out of aluminium and covered with 6 mm of rubber. Placed between the engine and the pilot.

Wing area/span: Area is 18 m² and the span is ~11 m. Wing loading: 178.5 kg/m².

NACA airfoil shape (wing profile): NACA 23015 at the base of the wing and NACA 23009 at the end of the wing.

The wings V-angle: 5 degrees 20 minutes, measured from the bottom wing surface.

Value of wing taper ratio: 0.565 (not sure if that is the correct translation of "trapetsisuusuhde", but it somehow tells how much the tip and root chords differ from each other)

EDIT #1: The information is taken from http://www.vlmyrsky.fi/ , i've taken info from pages like answers to questions (Kysymykset -> Historiakysymykset), performance, comparison (Historia -> Vertailukohteet), structure and so on. You can find performance and structure in English, but answers to questions are mostly in Finnish, and the comparison is also in Finnish.

The seat is a 10 mm steel plate, covered with leather and felt.

Length: 8.35 m

Height: 3.00 m

Horizontal tail area: 2.38 m²

Aileron tail area: 1.73 m²

Empty weight according to (http://www.vlmyrsky.fi/en/22): 2337 kg

Turning time: 180^o takes 10,8 s and 360^o takes 18,5 s according to (http://www.vlmyrsky.fi/en/22)

"Part of vertical tail belong to the frame structure. The rest of vertical tail and horisontal tail are wooden structure covered by plywood. The rudder and elevators are duralumin structure with fabric covering."

"The rounded cross section has been built by using wooden formers. The front part of the fuselage is covered by duralumin sheets and the rear part by birch plywood."

"The sight TH-m/44 KK was designed by Vilho Väisälä"

"There are collection boxes for empty cases."

"The spinner has short blades to enhance engine cooling."

These two are pretty much the same, but with differences in description

"The wing is a wooden structure. Spars are box beams with three plywood waists. The upper spar edge is made from pine and the lower from laminated veneer lumber. The spars divided plywood ribs to three parts."
"Wooden wing with two spars. Spars are box beam structure where waists are made from veneer, and flanges from laminated veneer lumber and pine. Three-piece ribs are made from birch veneer and strengthened by pine strips."

"Wing is covered by birch veneer."

"Ailerons have welded steel tube structure with fabric covering."

"Flaps are made from duralumin plate."

"Wing attached to fuselage with four bolts."

Landing gear: "Steel structure, steel spring suspension and with oil shock absorption."

[Finished! Because i'm bored]

Sources: Lentäjän Näkökulma by Jukka Raunio, pages 102 - 135.

Finnish Air Force fighters: History, camouflages and markings 1939 - 1945 part 2 by Kari Stenman & Karolina Holda.

Edited November 18, 2016 by LunarRainbow
two extra pictures i didn't need. More info of the vehicle

blakeob · September 2, 2016

Open for discussion. :yes_yes_yes: :salute:

Please get some sources to make your suggestion complete.

_Sync · September 3, 2016

Sure, why not? I would like it as a German premium

LunarRainbow · September 3, 2016

5 hours ago, _Sync said:

Sure, why not? I would like it as a German premium

A premium does sound good. Especially i don't have any idea where in the tech tree to put it as a non-premium.

But i was also thinking of adding another Finnish made warplane. The VL Pyörremyrsky a.k.a "Puumersu" (Wooden-messerscmhitt). Although only the engine, propeller and the Mg151 was retained from the 109. 1 prototype built, around 27 hours of flight time. Now that would be a proper premium.