The VL Pyörremyrsky (translates as Hurricane) was a prototype Finnish fighter plane designed to keep up with its contemporaries. It was to be domestically produced, using wood, but using the same engine as the Bf 109 G. Due to limitations brought about due to the war, only one prototype was produced and it wasn’t ready until the end of 1945.
Development and History
As Finland found itself still at war with the Soviet Union in 1942, with no end in sight, it turned to ways to bolster its military force. In order to become as self sufficient as possible, it was engaged in various projects for domestically designed and produced weapons systems. The VL Myrsky project was severely behind schedule and the air force realised that it would be outclassed by the newer Soviet aircraft by the time it reached production. With this in mind, it placed order number 2012/42 on 26th November 1942 for a new aircraft design, under the name Pyörremyrsky.
The State Aircraft Factory (Valtion Lentokonetehdas) was tasked with producing the new fighter and Captain of Engineering Torsti Verkkola was assigned chief designer of the team. The main premise was that the aircraft was to be made out of wood, as much as was possible, and that it was to be comparable with the German Messerschmitt Bf 109G. Verkkola used the Bf 109 as the base for his design, making modifications to allow it to be produced with local skills and materials. However, as the war dragged on, and the Finnish Air Force required more proven aircraft, as well as repairs to the planes already in service, the Pyörremyrsky found itself given a lower priority.
Upon the cessation of hostilities between Finland and the Soviet Union in September 1944, the Pyörremyrsky project had only a partially completed prototype and the Ministry of Defence (puolustusministeriö) cancelled the advance order of 40 aircraft, as well as the second prototype on the 29th September, but they did allow the first prototype to be completed. In Autumn 1945 the prototype, now christened PM-1 (which led to the nickname Puu-Mersu or Wooden Messerschmitt), was ready for pilot tests. On the 21st of November 1945, Luutnantti (Lieutenant) Esko Halme took off in PM-1 from Tampere-Härmälän airfield. The flight only lasted 25 minutes as part of the engines’ exhaust system came loose, forcing an emergency landing as Lt. Halme was unable to see through the exhaust blowing into his cockpit. Despite the incident, Halme reported good flying controls and characteristics. PM-1 would do 2 more test flights at Härmälän airfield before moving to Kuorevesi for Air Force testing. In total 31 test flights were performed, amounting to 27 hours of flight time. All 8 pilots reported the same, smooth and controlled flying characteristics, good speed and turning ability, however it was not quite up to the same performance of the Bf 109 G but close enough. The last flight of PM-1 was on the 22nd of July 1947, when Kapteeni (Captain) Osmo Kauppinen took off for a 20 minute general test flight. After this it was put into storage until it was officially removed from the Air Force’s rolls on the 1st April 1953. This was mainly due to the lack of ability to source new engine parts as part of the armistice Finland signed with the Allies forbade them from receiving military goods from Germany, as well as the decline of the piston aircraft as a fighter.
The Air Force didn’t want such a unique piece of Finnish aviation history to be scrapped however and ordered it to be preserved. It was sent to the State Aircraft Factory’s depot and was refurbished in the early 1970’s and sent to the Finnish Air Force Museum, where it is still on display.
The experiences learnt with the Pyörremyrsky were not totally in vain or wasted as the basic design was used in the development of the VL Vihuri fighter trainer.
Captain Verkkola used the Bf 109’s low-wing cantilever monoplane configuration as his base for the Pyörremyrsky. The Germans were also willing to supply the Daimler-Benz DB 605A-1 liquid cooled V12 engines and VDM 9-12087 three-bladed light-alloy propellers that were used on the Bf 109 series. It was also installed with a German produced Telefunken FuG 7a model of compact airborne receiver/transmitter.
The main body of the aircraft was built using the vast amounts of wood available to the Finns, with metal being used where absolutely necessary, like the cockpit and engine housing. While many believe the design is similar, if not copied from the Bf 109, there are many differences outside of just the materials used. The rear portion of the fuselage is of wooden monocoque design, with the horizontal stabilizers mounted at the near end, as opposed to the Bf 109’s which are mounted on the vertical stabilizer. The wings were of negative transverse V shape and covered in plywood panelling.
Unlike the wing fuel tanks found in the Bf 109, the Pyörremyrsky had a single tank behind the cockpit, protected by a 10mm thick armoured plate. The landing gear was copied from the Bf 109 but the Finns made some changes to eliminate the narrow and problematic system that plagued the Germans. The tailwheel was also retractable, thus helping it with aerodynamics.
Due to wartime shortages, Finland was forced to rely on substandard replacement products. The use of Lukko glue was one of the main reasons for the failings in the VL Myrsky and so it has been suspected that the Pyörremyrsky would have suffered similar issues to its sister aircraft had it been pushed into service or flown for longer periods of time.
Armament was not fitted to the PM-1 but it was designed to be installed with a Motorkanone mounted 20 mm (.78 in) MG 151/20 cannon and two nose mounted synchronized 12.7 mm LKK-42 machine guns. It was also proposed that the wings would have provisions for two 100kg bombs each for fighter bomber duties, but it is not clear if the proposal was ever considered seriously.
Finland – The VL Pyörremyrsky was intended to be used by the Finnish Air Force.
The VL Myrsky (translates as Storm) is a Finnish domestically produced fighter. 51 were manufactured between 1941 and 1945 and it was one of the fastest aircraft in the Finnish inventory at the time. Despite having good performance on paper, it was plagued with issues and uncertainty. It would be withdrawn from service in 1947 having served in numerous roles such as interceptor, fighter-bomber and reconnaissance.
Finland, being a small and newly independent nation, suffered from severe financial limitations and this included funds allocated towards its air force. However, the situation in 1930s Europe was not looking promising and in 1937 major funds were allocated to the defence budget for modernisation and expansion of Finland’s armed forces. By 1938, Finland had bought 7 Fokker D.XXI fighters, as well as the manufacturing license to produce more. However, Head of the Defence Council, Marshal Mannerheim, highlighted the need to produce a local fighter in order to lessen reliance upon foreigners in case of war. Major General Jarl Lundqvist, commander of the Finnish Air Force, replied that alternatives were being sought out but that high prices of specialised machinery, as well as many nations gearing up for war themselves, needed to produce such aircraft put limitations in place.
In early 1939, the Air Force made a survey of various aircraft designs and, upon completion in April, invited the State Aircraft Factory (Valtion lentokonetehdas) to ‘negotiations in Tampere on the construction of a prototype of a fighter machine in Finland’. On 4th May 1939, VL presented 5 different designs using the Bristol Taurus engine to the Ministry of Defence (puolustusministeriö) .
The Ministry of Defence placed contract 1094/39 with the State Aircraft Factory on 8th June 1939, which called for 33 aircraft to equip a fourth squadron. The design chosen was to be powered by the Bristol Taurus III 14-cylinder two-row radial aircraft engine, have semi-elliptical 19 square meter wings and retractable landing gear with allowances for ski pods. Its initial appearance was similar to the VL Pyry trainer which was undergoing prototype trials at the time.
However, when the United Kingdom declared war upon Germany in September 1939 due to its invasion of Poland, the possibility of acquiring the Bristol Taurus disappeared and a solution was needed. The design team thought the best replacement was the Pratt & Whitney R-1830-S3C3-G Twin Wasp and an order was placed. Due to the inevitable delays and mounting pressure in Europe, the Air Force placed an order for 35 Fiat G.50s to equip the fourth squadron. On 30th November 1939, Soviet forces attacked Finland in the opening moves of what would become known as the Winter War. This action put paid to many of Finland’s rearmament plans, including the Myrsky development, with an official order of termination being issued by the Ministry of Defence on 8th December (which seems to have not been fully complied with due to archival material showing dates during the Winter War).
After the conclusion of the Winter War on 13th March 1940, Finland saw itself in a critical situation which was further enhanced by the actions of Germany in Denmark and Norway. In April, the Finnish domestic programme was restarted with an emphasis upon speed, which led to more delays on the design. Finland reached out to both the US and Germany for more powerful engines, like the American Pratt & Whitney R-2800 Double Wasp and German BMW 801. However, the US put an export ban on war material in July and Germany was unwilling to sell any materials except captured ones like the Curtis 75A Hawk and Morane Saulnier MS 406. This then led to the placement of the programme in suspension until the winter of 1940.
On 20th December 1940, contract 1621/40 was issued ordering a prototype. About 60,000 hours went into the design phase, with 77,000 manhours going into the manufacture of the prototype. The original goal was for a working prototype to be completed in early July 1941 but, with the outbreak of the Continuation War, the project saw delays again. The prototype was finally completed in December and made its maiden flight on the 23rd December 1941 by Lieutenant (Luutnantti) Erkki Itävuori. A few redesigns were made during this second stage of development, the most notable being the copying of the tailplane of the Brewster Buffalo F2A. Given the serial MY-1, the prototype suffered from engine difficulties, as well as displaying a tendency to yaw. Also, it had a high wing loading (194 kg/m2) which meant that its rate of climb and maneuverability were compromised.
The MY-1 was redesigned and modified in order to fix the issues highlighted in the small scale test flights. The yaw was resolved by redesigning the whole rudder with an enlarged area and removing the supports from the horizontal stabilizers. Weight was reduced by changing the fuel tank, changing the engine gills and a few other minor changes, freeing up 317 kg and decreasing the wing loading to 175 kg/m2. The Hamilton Standard propeller was replaced by a locally designed VLS 8002 adjustable propeller and the exhaust pipes were modified to attain better thrust. Overall the MY-1 prototype went through four major modification stages and attained a final maximum speed of 519 km/h at 3250 meters altitude and a climb to 5000 metres in 6.5 minutes. While not perfect, the aircraft was seen as satisfactory. MY-1 took its last flight on 26th November 1943 with Captain (Kapteeni) Kokko, ending with a total logged time of 142 hours and 20 minutes in 162 flights.
Before the prototype’s test flights had all finished the Air Force placed an order for a pre-series of three aircraft to be produced on 30th May 1942. The idea was for these three aircraft to help test concepts and make mass production faster when the time came. These craft were serialled MY-2 to MY-4 respectively. MY-2 was completed in April 1943, it had thinner wings, Hamilton Standard metal propeller, pneumatic brakes and was the lightest Myrsky at 2150kg empty. It was destroyed on 6th ofMay 1943 when its engine failed from lack of fuel, Captain P.E. Sovelius was injured during the crash landing. MY-4 was finished 5th June, it boasted a thicker wing, easier removable engine, better cowlings, hydraulic brakes and the VLS 8002 adjustable propeller. It weighed in at 90 kg more than the MY-2, or 2 240 kg. MY-3 was completed on the 11th July, it weighed in at weighed 2 210 kg but was similar to the MY-2 except for slight modifications. This series was known officially as the I Series (I Sarja).
MY-3 made a belly landing on 5th August 1943 as the landing gear malfunctioned. During the repairs, they patched up the fuselage with plywood, adding another 10 kgs. Splines were added to the propeller spinner to help reduce overheating and these were carried over to the production models. After repairs the MY-3 was cleared for more flights, on 19th November 1943, during a test dive, aeroelastic flutter broke off the wings and then the tail, plunging the aircraft into the ground at 855 km / h. Warrant Officer (Vääpeli) Aarre Siltavuori was killed. Investigation after the event concluded that the wings needed to be reinforced and that dive speeds should not exceed 600 km/h.
MY-4 was continually used for testing and its armament layout was the one used in the production series. In February 1944 it was issued to No. 26 Fighter Squadron (Hävittäjälentolaivue 26) to assess its viability as a combat aircraft, it immediately caused problems as the 20 pilots who took turns to fly it noticed issues with its flying characteristics in comparison to their Fiat G.50s. On the 17th March, during a diving test the plane was attempting to spin to the right and lieutenant Jaakko Marttila struggled with the aircraft, under such stress the right wing finally broke at two metres from the tip, causing the plane to enter into an uncontrollable spinning dive that killed the pilot.
Production Series and the Continuation War
On the 18th August 1942, contract 1952/42 was issued that specified a production of 50 Myrskys, split into two batches. A three aircraft pre-series, as covered above, and a production series, to be called the II series, of 47 aircraft to be serialized as MY-5 to MY-51. MY-5 was completed in December 1943 and MY-51 was finished in December 1944.
The Myrsky continued to show problems during dives, MY-6 crashing due to the left elevator breaking loose when it reached 640 km/h in June 1944. This caused an order to reinforce all elevators, both on completed models and those going through production. Due to the numerous delays, the now adequate performance, as well as the many Bf 109’s supplied by Germany, the Fighter squadrons were not interested in the Myrsky. Indeed, only No. 26 Squadron were equipped with Myrskys to replace their aging Fiat G.50s but these were soon replaced by Brewster F2A Buffalo s. Orders from Air Force command saw the Myrsky banned from crossing the front lines due to their poor performance against contemporary Soviet fighters. Instead the reconnaissance squadrons (Tiedustelulentolaivue) gratefully received these speedy and modern aircraft, by comparison to their previous machines. No. 12 Reconnaissance Squadron became the first Myrsky reconnaissance unit in July 1944, there first mission was on the 9th August with a patrol flight in the Suistamo area where they attempted to intercept a flight of Yak-7 fighters with no results. The 22nd August saw the Myrskys baptism of fire when a 6 plane reconnaissance mission came across 3 Yak-9s at Mantsi. Lieutenant Linden scored confirmed hits upon one Yak but failed to bring it down, during the return flight Captain Virkkunen scored hits upon a La-5 but still not confirmed kills (after the war it was confirmed the Yak made an emergency landing at its home base and the La-5 suffered from damaged pressure systems).
During the later design phase, it was decided that the planes should be able to mount two 100 kg bombs. Pilots at the Tampere testing facility practiced the concept using weight concrete bricks but due to the planes relegation to reconnaissance, it was believed that the racks would not be used. However on the 3rd September, Captain Oiva Tylli led a six plane formation to bomb the Soviet 7th Army Corps headquarters at Orusjärvi (this saw the lifting of the crossing frontlines orders, as the HQ was some 35-40km behind the Soviet lines). 11 of the 12 bombs detached from their racks and damaged the lightly defended headquarters and the planes flew out of there before they could be intercepted. Later that same day the last combat mission of the Mysrky during the Continuation War took place, a four Myrsky flight was sent on a patrol at Sortavalan-Lahdenpohja but returned empty handed.
On the 4th September 1944 a ceasefire came into effect as a result of negotiations between the Finnish and Soviet Governments. No. 12 Reconnaissance Squadron was ordered to fly to Joroinen and await further orders. At the closing of hostilities, 44 of the 47 II series aircraft were completed. One squadron, No.12, was fully equipped, and another squadron, No.16, was partially equipped with six.
Lapland War and Peace
One of the stipulations of the ceasefire was the cessation of diplomatic relations with Nazi Germany and the expelling of Wehrmacht forces from Finnish territory by the 15th September 1944. With over 200,000 troops residing in Finland, as well as the essential nickel mines in Lapland, the Germans were both incapable and unwilling to withdraw in such a quick manner. This led to the outbreak of what became termed ‘The Lapland War’ (Lapin Sota).
A Finnish force of some 75,000 (4 Divisions as well as some attached elements) was assigned to the task of pushing the Germans from their land. A special air detachment was formed, Lentoryhmä Sarko, with the mission to support ground operations. 2nd flight of No. 12 Reconnaissance Squadron was subordinated to No. 26 Fighter Squadron at Kemi. Soon Myrskys were performing reconnaissance missions over Lapland but the severe weather soon put paid to any more flights by the Myrskys and on the 23rd November the last flight in combat conditions by a Myrsky was completed.
After the formalisation of the Moscow Armistice in September 1944, the Air Force was put in to peacetime strength in December. This saw a major reduction and restructuring of the Air Force as a whole. No.12 Reconnaissance Squadron became No.11 Fighter Squadron, and No.16 Reconnaissance Squadron became No.13 Fighter Squadron, these squadrons were amalgamations of other units and so were also equipped with BF-109G-2s and Curtiss Hawk 75As. The Myrskys continued to serve in these fighter units but were still subject to accidents, especially from stalling, which saw a suggestion to modified the wings with slots. MY-50, which was never issued to the air force but remained at the factory’s hanger, was modified with slotted wings but nothing went further. On 9th May 1947, Captain Kauko Ikonen, took MY-28 out for a training flight when it suddenly entered into a dive and broke up in the air. The plane plunged into the soft clay and was not recovered, No.11’s commander ordered a grounding of the entire Mysky fleet, which was confirmed by the Wing’s headquarters later that day.
The last flight of the Myrsky took place on 10th February 1948, when MY-50, was allowed to fly from its test hanger to Tampere for storage but as it came into land, it overshot the runway and landed on its belly.
Today there is a restoration project to bring back MY-14 to a fully reconditions state for display at the Finnish Aviation Museum. The project has reach a stage where it could be unveiled to the public for Finnish Air Force 100th anniversary air show in June 2018.
When the original order went out for the design, Arvo Ylinen (head of the design-bureau), Martti Vainio (aerodynamics), and Torsti Verkkola (structural design), were assigned the task of designing the new plane.
They decided to combined the learning they had from the Pyry trainer with the experience of licensed building of modern aircraft like the Fokker D.XXI. This allowed for not only cheaper design and production but also allowed for the design to be tweaked to Finnish desires. Due to the limitations upon Finnish industry (both due to its economic and geographical locations), it was decided that the design would be a combination of wood and metal.
The fuselage used a metal wire frame which was then covered with fabric and plywood, while the wings made from plywood and covered in a birch veneer (called Kolupuu).This did allow for cheaper production and lighter construction but contributed to the breaking of the wings upon reaching certain speeds. Because of the rarity of duraluminium, it was decided that the Myrsky should have none of it in its construction (but because of problems finding a suitable replacement, it was used in certain aspects of the machine like the flaps), instead aluminum (which had been bought from Norway and Sweden before the war) would be used sparingly and combined with specialised wooden parts.
The generalised design was the conventional piston aircraft, with a low wing attached just forward of center. The cockpit suffered from the same issues that many of its contemporaries did, in that the long nose limited its forward vision, but it is have excellent side visibility. The armament was four VKT 12,70 mm LKk/42 machine guns, mounted two per side of the engine, these were synchronised to fire through the propeller. It was also decided to add a hard point under each wing which would allow for an additional fuel tank or a 100kg bomb to be used.
Due to wartime shortages, Finland was forced to rely on substandard, replacement products. The use of Lukko glue was one of the main reasons for the failings in the Myrsky. It was not of the same quality as pre-war glue and did not stand up to rain, frost and humidity (a common occurrence in Finland), and would require more man hours to keep the aircraft in a flyable condition.
During its lifespan, the Myrsky was involved in 48 separate incidents, 10 of these resulted in the complete loss of the aircraft and 4 pilots died as a result.
MY-2 was destroyed on 6th May 1943 when its engine failed from lack of fuel, Captain P.E. Sovelius was injured during the crash landing.
MY-3 was destroyed on 19th November 1943 when aeroelastic flutter broke the wings of the aircraft. The Pilot, Warrant Officer Aarre Siltavuori was killed
MY-4 was lost on 17th March 1944 during a training flight. The plane entered into a dive which then broke one of the wings. Lieutenant Jaakko Marttila died in the crash.
MY-29 was destroyed on 4th September 1944 during a transfer flight. Lieutenant Aulis Kurje lost control of his aircraft when the engine overheated and cut out. The plane crashed into the wood, causing the seat to break free, killing the pilot.
MY-25 was destroyed on 13th November, 1944. During a reconnaissance flight near Kemi, MY-25s engine cut out forcing Lieutenant Berndt Schultze to perform a crash landing, he sustained minor injuries.
MY-27 was destroyed on 26th January 1945. After a crash landing on the 23rd January 1945, it was decided to fly the aircraft down to Pori, during the flight the fuel ran out. Warrant Officer N. Satomaa crashed the plane into a forest near Veteli. He was badly wounded but survived.
The MY-26 was destroyed 25th December, 1945. Due to malfunction, Staff Sergeant (Ylikersantti) E. Tähtö was forced to crash land in Pori. He walked away with minor injuries.
MY-24 was destroyed on 11th December 1945. Sergeant (Kersantti) Onni Kuuluvainen lost control of his craft when performing a speed correction. After several attempts to recover the plane he parachuted to safety. The plane crashed into a farmer’s field in the Pori area.
MY-5 was destroyed on November 20th, 1946. Lance corporal (Korpraali) Erkki Jaakkola was forced to make a crash landing in a field after his plane suffered from a fuel feeding problem after climbing to 7,000 metres.
MY-28 was destroyed on 9th May, 1947. During a training session, Captain Kauko Ikonen lost control of his plane, which then broke into pieces and smashed into the ground at Nakkila. This caused the entire Myrsky fleet to be grounded.
VL Myrsky – Myrsky prototype. Serialled MY-1. It differed from the later versions in being armed with two fuselage mounted 12,7mm mgs and four wing mounted 7,7mm mgs in the wings. It also had the Pratt & Whitney R-1830-S3C3-G Twin Wasp engine. The altitude stabilizers were originally supported but removed during the stage III modifications. Its undercarriage is also 15cm longer, giving it a more angled appearance when on a flat surface. Only 1 produced
VL Myrsky I – The pre-series production. Used to test ideas from the prototype, and to help gain experience in production. Each one was slightly different with various modifications. These were powered with the Pratt & Whitney R-1830-SC3-G Twin Wasp engine. They had more fabric pieces than their production counterparts. 3 produced.
VL Myrsky II – The production series. Taking the experience gained in the prototype and pre-series phases and putting it into practice. Using the R-1830-SC3-G Twin Wasp engine, it was modified with different gears to produce 1,155 horsepower on take-off. 47 were built.
VL Myrsky III – In March 1944 an order for 10 improved Myrsky versions was given to the State Aircraft Factory. This order was cancelled on 30th September 1944 and the whole series was cancelled on 30th May 1945.
The VL Myrsky was the embodiment of Finnish thinking, small and quick, hard hitting but light. The domestic fighter programme would not only bring more jobs to the locals but would be a point of pride that Finland could stand its own if it needs be. Also, as it was the only domestic fighter to see service during the war, it became a symbol of pride of Finnish independence.
Because of the many delays in its production, by the time it arrived on the front lines, the war had stabilized into what is termed ‘asemasota kausi,’ or The Trench War period. This meant that the war was much quieter in comparison to the other fronts that the Soviets were fighting on. The fighter pilots reports upon its mediocre performance in terms of speed and maneuverability in comparison to the Yaks and Las they were facing but the reconnaissance pilots reported positively upon these characteristics. It occupied the second fastest serving aircraft in the Finnish Air Force (only the BF-109 being faster) and its cockpit ergonomics were favorable and the pilots enjoyed its ground handling properties, thanks to the wide undercarriage.
It was far from the perfect aircraft, at low speeds it had a tendency to stall to the left. Its batteries tended to drain quickly if not pulled from the aircraft when not in use and the metal parts were prone to rusting. The inferior quality of the glue used during the war meant that more maintenance was required to keep the airframe flight worthy, reports of seams on the wing surfaces, rudder and elevators opening were a common occurrence. Pilots, both fighter and reconnaissance, reported upon the armament being too weak to take on the modern Soviet fighters and that due to the engine being governed, the plane was ‘too slow’ for what it should have been.
Finland – The VL Myrsky was only used by the Finnish Air Force
VL Myrsky II
36.08 ft / 11.00 m
27.39 ft / 8.35 m
9.84 ft / 3.00 m
193.75 ft² / 18.00 m²
1x Pratt & Whitney R-1830-SC3-G Twin Wasp modified (1,155 hp)
7,083 lbs / 3,213 kg
5,152 lbs / 2,337 kg
49.21 ft/s / 15.00 m/s
292.04 mph / 470 km/h at Sea Level
332.43 mph / 535 km/h at 10830 ft / 3,300 m
Maximum Service Ceiling
31,170 ft / 9,500 m
4x 12.7mm VKT 12,70 Lkk/42 (960 Rounds Total)
2x 220.5 lb /100 kg Bombs or
2x 39.62 Gal / 150 L Drop Tank
The Hakaristi (Finnish Swastika)
It is important to note the use of the ‘Swastika’ on Finnish military equipment due to the confusion of its application.
Finland first adopted the Swastika (known as Hakaristi, broken cross, in Finnish) on the 18th March 1918, thanks to a donated aircraft that arrived earlier that month from Swedish Count Eric von Rosen (who used a blue swastika as his personal symbol). The Hakaristi became a national symbol from that moment, being used on everything from the Medal of the War of Liberation, the Mannerheim Cross, tanks, aircraft, to even a Women’s auxiliary organisation.
It became part of the official Air Force insignia, being used as an identification symbol as well as on certain badges and awards, from its inception in 1918 and today is still maintained upon certain symbols like the Standards of Commands.
Due to this early adoption, it has no association with the Nazi regime and the usage of such a symbol by both parties is only a coincidence.