VL. (Finnish) pre.1945 projects and prototypes

[Taranov]

Re: VL Finnish pre-1945 Fighter Projects

VL Myrsky

 

[topspeed3]

Re: VL Finnish pre-1945 Fighter Projects

This would indicate that there was after all a difficulty to get the right glue; http://en.wikipedia.org/wiki/VL_Myrsky
Looks a lot like the Fokker D XXI;
http://www.youtube.com/watch?v=qGOnHDG3Ems


----------------

The need for Puuska expired in summer 1944 when president Risto Ryti had been able to acquire 150 Messerschmitts ( 109 G-6s ) with his personal promise not to let down Axis powers in fight against the USSR.

 

[topspeed3]

Re: VL Finnish pre-1945 Fighter Projects

Here is the worst distortion about FAF swastika I have come a cross so far; http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=936

...reads....thusly it carried blue German Swastika on white background !

Finnish AF had carried same emblem before nazism had even been born !
But FAF did have yellow eastern front bands in the fuselage and yellow wingtips underneath to signal AAA about finnish ( or axis ) aeroplane.

Latvian AF also had swastika, but its origins I do not know; http://surfcity.kund.dalnet.se/gladiator_latvia.htm

 

[mz]

Re: VL Finnish pre-1945 Fighter Projects

This would indicate that there was after all a difficulty to get the right glue; http://en.wikipedia.org/wiki/VL_Myrsky
...
The need for Puuska expired in summer 1944 when president Risto Ryti had been able to acquire 150 Messerschmitts ( 109 G-6s ) with his personal promise not to let down Axis powers in fight against the USSR.

If you read the VL factory history part 2, as well as a smaller book about the VL Myrsky airplane, both by Jukka Raunio, you get a strong indication that the glue was a problem. Originally they had good quality Tego-film from a German chemical factory for producing weather resistant veneer. It was a paper like film that was put between layers of veneer in a press. But when the availability ended (1943 bombing of Wuppertal) and they ran out of Tego-film stocks then substitutes were used and developed and tested (milk based etc). There were weather problems with those. http://en.wikipedia.org/wiki/Tego_film

The whole summary about Myrsky was that it was a failure: VL just didn't have experience with high speed aircraft, having just produced simpler wood and fabric trainers earlier. The aircraft shook themselves apart in flutter. Around 1939 nobody would sell aluminium and Finland did not have indigenous production. The country was a mostly agricultural backwater, modernizing itself in a hurry in the war and afterwards with the massive war reparations.

The most important contribution of VL was repairing imported aircraft (Fokkers, Brewsters, Messerschmitts, Junkers etc).

Tuuli = Wind
Puuska = Gust
Vihuri = Hard wind (not to be confused with the Wihuri industrial family / company)
Pyörremyrsky = Tornado

 

[Apophenia]

Re: VL Finnish pre-1945 Fighter Projects

Latvian AF also had swastika, but its origins I do not know;...

OT, but ... "Latvian left-facing swastika or Thunder Cross [pērkonkrusts] dates back to Bronze Age. It is widely seen scratched on the surfaces like rocks, weapons and pottery as a protector sign." http://en.wikipedia.org/wiki/Western_use_of_the_swastika_in_the_early_20th_century#Latvia

 

[topspeed3]

Re: VL Finnish pre-1945 Fighter Projects

Latvian AF also had swastika, but its origins I do not know;...

OT, but ... "Latvian left-facing swastika or Thunder Cross [pērkonkrusts] dates back to Bronze Age. It is widely seen scratched on the surfaces like rocks, weapons and pottery as a protector sign." http://en.wikipedia.org/wiki/Western_use_of_the_swastika_in_the_early_20th_century#Latvia

What ever you may think of the swastikas...I think this looks a bit tasteless; http://www.cantrell.cc/2010/06/lithuanian-swastikas/
Lithuanian cheese with swastika label.
Lithuanian AF did not use swastikas in their aeroplanes

 

[TsrJoe]

ahem ... VL. (Finnish) pre.1945 projects and prototypes

 

[topspeed3]

How about VL Pyry ( Blizzard ) ?

It had several different modifications and subtypes with different wing etc.

 

[Jan den Das]

This one was fitted with a Myrsky wing

 

[Retired In Kalifornia]

Re: VL Finnish pre-1945 Fighter Projects

An american artist Richard Lewis Mendez [Mendes] who recently passed away drew this above..know the bomber ?

Uh, per Monty Python: "I'm Not Dead - Yet!" The bomber is a Myasischev DVB-102. I drew this art piece in November 2000. All my art produced since 2006 is here: http://www.luft46.com/rmart/lufartrm.html all that surviving prior to that year is backed up to my external HDDs though a fair number of my pieces produced prior to that year, including a few harking back to 1999 if not earlier, are still up on the Internet. Am on hiatus drawing art till I get more of my extensive collection of 1/72 scale Regia Aeronautica Italia airplane models built, been on them continuously since 2009 and am 1/2 way building through that stockpile never mind those of other nationalities!

I draw traditional portraiture style very laboriously rendered using Corel Graphic Suite software. Current 3-D CG renderings up on the Web by others which are even more laboriously rendered are fabulous, but to my eye don't bring forth life on the canvas like old timey portraiture. For years I've debated whether to reestablish my Internet graphics arts website I'd had up between 1997 & 2000, if I do it'll include everything I'd produced going back to 1997 along with new renderings. One I absolutely want to complete before I DO die are original twin-tail design CONVAIR B-36 bombers flying in formation, other than art sketches produced by CONVAIR c.1942 of the original design nobody else has done that - so far.

 

[athpilot]

Hey!
Glad to hear you are alive!!
And then I read this: "For years I've debated whether to reestablish my Internet graphics arts website I'd had up between 1997 & 2000, if I do it'll include everything I'd produced going back to 1997 along with new renderings." Cooool!! Please do it. I always liked your renderings. And the Luft46-Website needs (urgently) fresh and good new Pictures.
Greetings from Germany

 

[Retired In Kalifornia]

Hey!
Glad to hear you are alive!!
And then I read this: "For years I've debated whether to reestablish my Internet graphics arts website I'd had up between 1997 & 2000, if I do it'll include everything I'd produced going back to 1997 along with new renderings." Cooool!! Please do it. I always liked your renderings. And the Luft46-Website needs (urgently) fresh and good new Pictures.
Greetings from Germany

Thanks for the complement! I still have all but couple of my 1997-2000 graphic arts website JPEGs; for your enjoyment here is the oldest aviation one c. September 1997:

Göring & Galland are discussing a "secret mission" with these airplanes, Galland ain't at all happy with this mix, that ain't a Nazi salute he's giving!

I'd prefer to have somebody host my art pieces rather than launch a new website, was a pain back then maintaining mine! I don't know how long luft46.com will be going, the website owner hinted to me months ago it may be taken down next year, would be very sad especially as he's hosting all my current art on it!

 

[Apteryx]

Mr. Mendes, I too celebrate your status!

for your enjoyment here is the oldest aviation one c. September 1997:

I remember that picture fondly, although it was bigger, no? Or were JPEGs all just smaller in those bygone days? There's something special about vector art--I hope you can share more of those images one way or the other.

 

[Retired In Kalifornia]

Mr. Mendes, I too celebrate your status!

for your enjoyment here is the oldest aviation one c. September 1997:

I remember that picture fondly, although it was bigger, no? Or were JPEGs all just smaller in those bygone days? There's something special about vector art--I hope you can share more of those images one way or the other.

That's actual sized I'd saved it. Its one of my largest art renderings if not the largest in my portfolio. Remember back when we had to cram things in 14-inch or smaller glass tube screens?! I had to make a small JPEG of it for folks to click on this one as y'all back then couldn't see it without scrolling left & right. I have a 30-inch PC monitor, thing looks tiny to me now LOL! Here's something that was up for a very short time on the "old" jetx.org website many moons ago:

​

Can't say it was one of my better art renderings, but y'all can appreciate the comedy of it!

 

[GTX]

Sigh...if only that were a real kit

 

[Retired In Kalifornia]

Sigh...if only that were a real kit

Closest thing to it is this: Antaries Heinkel He 177 B-5/R1 ( He 277) conversion set I bought one earlier this year, listed U.S. $40 but y'all have to buy the Revell He-177 kit to go with it (yes, I did think about adapting it to the old Airfix kit but better sense prevailed here ala didn't wanna chance any mess-ups!):

And this also (y'all have choice of single above or twin below tail configurations with the conversion kit):

It will be years till I get to it BTW; like the paint schemes though think they ain't RLM spec LOL!

 

[GTX]

Unfortunately for me I prefer 1/48 for my aircraft models.

 

[perttime]

There's a slow project for the restoration of a VL Myrsky:
http://www.vlmyrsky.fi/en
(Menu for English pages is all under the "English" link.)

They had some parts on display at 2014 http://www.jamiflyin.com/ . When I had a short chat about it, the guys said that what they are building from scratch is done good enough to fly (using modern glues) - but the best they are dreaming of is to get it good enough to run the engine. Apparently, they are not currently sure if the fuselage that they have is good enough for even that.

 

[TsrJoe]

back on topic ... cheers for sharing the Myrsky link, it'll be good to see it when its completed at some of the shows in a few years time even if just ground running

joe B)

 

[Pioneer]

Re: VL Finnish pre-1945 Fighter Projects

Puuska with few other planes from same era in comparison.

Please excuse my ignorance topspeed3, but are these profiles to scale?

Regards
Pioneer

 

[Retired In Kalifornia]

Sigh...if only that were a real kit

Closest thing to it is this: Antaries Heinkel He 177 B-5/R1 ( He 277) conversion set I bought one earlier this year, listed U.S. $40 but y'all have to buy the Revell He-177 kit to go with it (yes, I did think about adapting it to the old Airfix kit but better sense prevailed here ala didn't wanna chance any mess-ups!):

It will be years till I get to it BTW; like the paint schemes though think they ain't RLM spec LOL!

Sadly it likely will be more years if ever can build this conversion, gave away all but my 1964-1966 Air Lines (FROG) kit collection in November 2015, no room where live now to store it. Antaries ANT-7209 He.277 conversion resin kits still are available for U.S. $60 via their website, may buy another at some point though still have 35 Regia Aeronautica Italia/Aeronautica Nazionale Repubblicana left to build before getting to anything else hopefully by 2021 assuming am alive, eyes & hands remain good & steady.

 

[hesham]

Hi,

the Karhumäki Tiira was a two-seat parasol wing light monoplane of 1929,
and the Karhumäki Viri was a single seat parasol-high -wing very light sport
monoplane of 1935.

 

[Apophenia]

Just to be clear, neither the Tiira nor the Viri have anything to do with V.L. Indeed the Karhumäki factory would not be merged into V.L.'s successor, Valmet, until 1963.

The Tiira was a homebuilt by the brothers Niilo and Valto Karhumäki. The Viri was built by their firm, Veljekset Karhumäki O/Y at Keljo. The brothers had home-built three designs before the Tiira. Their earliest designs were shoulder-winged light monoplanes - the Karhu (Bear) and Karhu 2. The Karhu 3 was a stronger, low-winged monoplane.

After WW2, Veljekset Karhumäki O/Y produced the Karhu 48, a 4-seat cabin monoplane.
-- https://1000aircraftphotos.com/Contributions/VigneronPhilippe/10661.htm

Karhumäki Karhu - 1925 (Bear) homebuilt monoplane, x 1
- Karhu : Single-seat shoulder-wing ultralight aircraft
- Karhu : 1 x 4 hp or ~8.5 hp engine,* span 9.50 m
-- * Karhu incapable of flight with orig. boat motor
-- * Flew with a Harley-Davidson 24 FE motorcycle engine
-- c/n 1, aka Karhu 1 (back-formation), wooden constr'n
-- https://upload.wikimedia.org/wikipedia/commons/f/f5/Karhu_1.jpg

Karhumäki Karhu 2 - 1927 (Bear 2) homebuilt monoplane, x 1
- Karhu 2: Shoulder-wing 2-seater, enlarged 'Karhu 1'
- Karhu 2: 1 x 32 hp British Anzani/Vulpine V-2, span ~12 m
- Karhu 2: c/n 2, w/o 04 Dec 1927 flying off a frozen lake
-- https://upload.wikimedia.org/wikipedia/commons/0/04/Karhu_2.jpg

Karhumäki Karhu 3 - 1928 (Bear 3) homebuilt monoplane, x 1
- Karhu 3: Low-winged 2-seater, enlarged 'Karhu 1'
- Karhu 3: 1 x Haacke HFM-2, repl. by 32 hp Vulpine V-2 *
-- c/n 3, * British Anzani/Vulpine V-2 taken from Karhu 2
-- https://upload.wikimedia.org/wikipedia/commons/2/2b/Karhu_3.jpg
-- Pilven Pentti: 1941 OH-PPA from Karhu 3 wings & nose
-- Pilven Pentti monoplane never flew, was scrapped in 1943
-- Sutinen & Mäkinen Pentti were neighbours of the Karhumäkis

Karhumäki Tiira: ('Tern') 1929 2-seat, folding-wing lightplane
- Tiira: 1 x 60 hp Anzani 6B 6-cyl. radial, span 10.60 m
- Tiira: Reg. K-SIRA, after 1931 OH-IRA, decommissioned 1931

Karhumäki Viri: ('Breath of wind') 1929 single-seat lightplane
- Viri: 1 x 37 hp Szekely SR-3-0 inv. Y-3, span 8.00 m
-- Design was by Arvo Ylinen (later resp. for VL Tuisku)

 

[Justo Miranda]

Finnish Fighters​

Ilmailuvoimain Lentokonethdas - IVL (Aviation Force Aircraft Factory) made under license, between 1922 and 1925, hundred-and-twenty Hansa-Brandenburg W.33 floatplanes, thirty-four Caudron C.60 and six Morane-Saulnier M.S.50c

The first indigenous fighter, the prototype IVL C.24, with parasol wing inspired by Morane designs, was flown on 16 April 1924 and the C.25, an improved version with narrower-chord wing, was flown on June 1925. Both models suffered longitudinal stability problems caused by the excessive weight of the Siemens Sh 3A engine. Its serial production was dismissed after an accident suffered by the C-25

The next attempt to provide the Ilmailuvoimat with an indigenous fighter was the IVL D-26 Haukka. The biplane prototype was flown on 17 March 1927, manifesting structural faults and flat spin tendence. Both problems were not fully resolved in its successor D-27 Haukka II and its production was again dismissed in favor of licence-built Gloster Gamecock Mk.II.

In 1928 the IVL became Valtion Lentokonetehdas-V.L. (State Aircraft Factory). Before the war, V.L. had built some self-designed trainers and second line aircrafts: it produced thirty-three units of the Saaski reconnaissance airplanes in 1928, seven Kotka light bombers in 1930, thirty-one Tuisku advanced trainers in 1933, twenty-four Viima elementary trainers in 1935 and forty-one Pyry advanced monoplane trainers in 1939, but no fighters.

V.L. Myrsky (470 kph)​

On 8 June 1939, the Ministry of Defence instructed V.L. to design a new single-seat fighter powered by a Bristol Taurus III engine.

V.L. just didn't have experience with high speed aircraft, there wasn't any duraluminium production in Finland and nobody would sell aluminium in 1939. The Taurus engine was not available due to war and a 1,065 hp (with 87 octane fuel) Swedish-built civilian version of the Pratt & Whitney R-1830 was chosen. V.L. then decided to use the same construction system of the Fokker D.XXI. The wings and tail surfaces were made of wood/plywood and the fuselage structure was welded chrome-molybdenum steel tube with fabric and plywood coating.

The prototype was flown on 23 December 1941, manifesting serious yaw to port, excessive wing loading and engine problems. On 30 May 1942, the Department of War Supplies had placed an order for three pre-production aircraft called Myrsky I.

Built between April and June 1943, the three planes suffered accidents and two of them were destroyed, during diving tests, for fractures of the wing attachement bolts and plywood skinning under stress, due to defective bonding.

The investigation board confirmed that flutter had caused the wings to break up and recommended that they be strengthened in the forty-seven Myrsky II (525 kph) that began to be manufactured in July 1944. The fuselage fabric covering was replaced in these aircraft with plywood sheeting, the elevators and the landing gear were strengthened and a VLS 8002 constant-speed propeller (with wooden blades and cooling fan) was installed. The construction of the Myrsky II complicated when the availability of the German Tego-film glue ended, after the destruction of its manufacturing plant in 1943. It was replaced by bad Finnish glues based on casein.
Maximum permissible diving speed was raised to 650 kph and maximum engine revolutions were restricted to 3,060 r.p.m. The armament consisted of four 12.7 mm VKT LKk/42 machine guns.

The Myrsky II entered service with Ilmavoimat in July 1944, being used mainly in reconnaissance missions.

In August and September, the Myrsky II fought against two Yak-7, three Yak-9 and two La-5 of the 195 IAP, damaging several of them but without achieving any victory before ceasefire. Until being retired from service, on February 1948, the Myrsky fighters had suffered a total of 51 accidents, with the loss of 21 aircrafts and four pilots.

V.L. Pyörremyrsky (522 kph).​

At the end of 1942, the V.L. tried to negotiate a full reparation license for the Messerschmitt Bf 109 G-2, but complete sets of drawings and tools were never delivered.

The Ilmavoimat had been particularly concerned with the debut in some numbers of the Lavockin La-5 Soviet fighter and the possibility of the Germans to suspend the supply of fighters. The Pyörremyrsky programme began when the Ilmavoimat ordered two new Finnish fighters into design phase: Pyörremyrsky and Puuska.

The design was given the following basic parameters:

At least 50 km/h faster of the fastest enemy bomber
If faster than enemy fighters, it may be less agile and worse climber
If slower than enemy fighters, it must be better climber and more agile

By early 1943, V.L. was instructed to design a single-seat fighter powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving a VDM three-bladed airscrew. Since it was impossible to import aluminium due to the war, the Pyörremyrsky should be built using only domestic materials, incorporating the lessons learned from the construction of the Myrsky.

The single-spar wing was built in wood/plywood, with metal-framed, fabric-covered ailerons and electrically-operated metallic flaps. The tail assembly was also built in a similar way with metal-framed movable surfaces. The forward fuselage structure was welded chrome-molybdenum steel tube, and the aft fuselage was a Soviet-style wooden monocoque structure. The armament consisted of one engine-mounted 20 mm MG 151 cannon and two 12.7 mm LKk / 42 machine guns in the nose.

Prototype construction was low, affected by the unavailability of the German Tego-film glue and the airplane was still not completed in September 1944, when the peace treaty was signed. On 21 November 1945 during their flight testings the new fighter proved to be more manoeuvrable than the Bf 109 G-6, with an outstanding climb rate and few teething troubles.

Unfortunately, the series production was dismissed because of the difficulty in obtaining a supply of Daimler-Benz engines.

V.L. Puuska (650 kph)​

In the fall of 1943, V.L. was instructed to design a single-seat lightweight fighter, with narrow-track undercarriage, powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving three-bladed VDM airscrew.

The design should adapt to the new fighter tactics of the Ilmavoimat, which was considered outdated the dog fight, preferring the ‘zoom and climb’ to either repeat the attack, or break off the contact with an advantage in speed and climb. To meet the specification, it was necessary to design a light airframe to take full advantage of the 1,475 hp of the available engine.

The result was the Puuska, an 80 per cent smaller and light version of Pyörremyrsky that V.L. offered to the Ilmavoimat at the end of 1943. Out of the five proposed designs, the Finnish Air Force Material and Procurement staff selected two on 24 January 1944, called PM-3 and PM-5, to be built as prototypes that were to be ready on 1 July 1945. The PM-3 should use the under nose oil cooler and two radiators from Bf 109 G-2 under the wings, local manufacture Sperry artificial horizon, Hollsman compass and Vaisala reflector gunsight.

The double-joint undercarriage retraction system would use Siemens and Stromberg electrical motors and two 660 x 160 mm wheels from Bf 109 G-2. The proposed armament was one engine-mounted 20 mm MG 151 cannon, with 300 rounds, and two 12.7 VKT LKk/42 mm nose-mounted machine guns.

Wingspan: 9.2 m, length: 7.5 m, wing area: 13.5 sq.m, maximum weight: 3,200 kg, maximum speed: 620 kph, climb rate: 6.2 min to 6,000 m., service ceiling: 12,000 m.

The PM-5 was designed as a point-defence interceptor, very fast and with amazing climb rate. To save weight they decided not to install armour and the armament was reduced to a MG 151 with 210 rounds. The internal fuel was also reduced to only 400 litres, with the possibility of carrying two drop tanks of 140 litres each under the wings.

Oil and glycol radiators were grouped in a ventral nacelle to save drag.

It was expected that series aircraft were equipped with a Telefunken FuG-7a R/T device and used the main wheels from Soviet LaGG-3 and the retractable tail wheel from DB-2 bomber. The building system should be the same used in the Pyörremyrsky, but the project was cancelled on March 1944 due the low availability of DB engines.

Maximum weight: 2,650 kg, maximum speed: 682 kph, climb rate: 4.7 min to 6,000 m, service ceiling: 14,000 m.

V.L. Humu (430 kph)​

In October 1942, the Ilmavoimat placed an order with the V.L. for four prototypes of the Humu, a copy of the Brewster 239 fighter that should be built in wood/plywood/steel with the same technique used in the Fokker D.XXI. It was expected to build a series of 55 aircraft, using instrument and M-63 engines from captured Soviet airplanes.

On 8 August 1944, the prototype was flown, powered by a 930 hp Shvetsov M-63, reaching the 420 kph. A surplus Brewster fuselage and new wings built in wood/plywood by V.L. had been used for its construction. It turned out to be too heavy (2,895 kg) manifesting problems of longitudinal stability, and the initiation of series production was delayed pending results of flying tests. The proposed armament were three 12.7 mm LKk / 72 machine guns.

The project was cancelled in the summer of 1944.

Fokker D.XXI modified​

Earlier, in 1939, the Finns had experimentally fitted two underwing 20 mm Oerlikon cannons in the Fokker FR-76.

On 29 January 1940 the FR-76 shoot down a Soviet DB-3M bomber with just 18 rounds, but the excessive weight limited its performances and the experiment was discontinued.

Another attempt to improve the outdated fighter consisted in installing a modified wing (the so-called E-wing) in the FR-121. It had more dihedral and was more tapered that the standard wing.

During flight tests it was found that the gun access panel blew off as a result of the air pressure in the gun bay.

Finally, two Fokkers were modified with a retractable landing gear: the FR-117 (Mercury) on 27 April 1941, and the FR-167 (Twin Wasp) on 2 March 1942. Both aircraft were later equipped with a fixed gear, and the whole idea was dropped because the speed improvement was only 15-37 kph, depending of altitude.

V.L. Vihuri​

In 1943 the Finns were waiting to receive two crashed British de Havilland Mosquito, requested from Germany to serve as models for planned production. One would be repaired and another one would be teared into parts to make blueprints. The Finns are great wood workers and probably would have been able to circumvent the unavailability of balsa and Tego-film, with the technique used by the Soviets in the construction of the Polikarpov I-16, which already had been tested in the Pyörremyrsky. The Polikarpov fuselage was built in two halves, like the Mosquito, and each half comprised pine frames and longerons. The monocoque skin was produced from layers of birch strips glued cross-grained and molded on a former.

The new aircraft, called Vihuri, would have possibly been used as fighter-bomber with nose-mounted machine guns. It would have been powered by two 1,475 hp German Daimler-Benz DB 605 AC engines and used the landing gear of the Bristol Blenheim. It was estimated that its performances would have been inferior to those of the Mosquito because of its greater structural weight. Production plans would have delivered between mid of 1946 and December 1947, due to the overload of work that represented for V.L. the repair of fighters in service, the production of the Myrsky and the Mörkö-Moraani conversion.

Mörkö Moraani (525 kph)​

Starting from June 1944, forty-one Moranes were re-engined with one 1,100 hp Klimov (Hispano-Suiza) M-105 P driving one VISh-61P constant speed airscrew.

Only three modified aircraft entered combat during the Continuation War, shooting down one La-5 and two Airacobra.

Armament: one engine mounted 20 mm MG 151 cannon and two wing-mounted 7.7 mm (belt feed) Browning machine guns.

 

[elmayerle]

Re: VL Finnish pre-1945 Fighter Projects

An american artist Richard Lewis Mendez who recently passed away drew this above..know the bomber ?

I beg to differ, he has not yet passed away and was still modelling and posting online as of earlier this year.

 

[Airborne2001]

Finnish Fighters​

Ilmailuvoimain Lentokonethdas - IVL (Aviation Force Aircraft Factory) made under license, between 1922 and 1925, hundred-and-twenty Hansa-Brandenburg W.33 floatplanes, thirty-four Caudron C.60 and six Morane-Saulnier M.S.50c

The first indigenous fighter, the prototype IVL C.24, with parasol wing inspired by Morane designs, was flown on 16 April 1924 and the C.25, an improved version with narrower-chord wing, was flown on June 1925. Both models suffered longitudinal stability problems caused by the excessive weight of the Siemens Sh 3A engine. Its serial production was dismissed after an accident suffered by the C-25

The next attempt to provide the Ilmailuvoimat with an indigenous fighter was the IVL D-26 Haukka. The biplane prototype was flown on 17 March 1927, manifesting structural faults and flat spin tendence. Both problems were not fully resolved in its successor D-27 Haukka II and its production was again dismissed in favor of licence-built Gloster Gamecock Mk.II.

In 1928 the IVL became Valtion Lentokonetehdas-V.L. (State Aircraft Factory). Before the war, V.L. had built some self-designed trainers and second line aircrafts: it produced thirty-three units of the Saaski reconnaissance airplanes in 1928, seven Kotka light bombers in 1930, thirty-one Tuisku advanced trainers in 1933, twenty-four Viima elementary trainers in 1935 and forty-one Pyry advanced monoplane trainers in 1939, but no fighters.

V.L. Myrsky (470 kph)​

On 8 June 1939, the Ministry of Defence instructed V.L. to design a new single-seat fighter powered by a Bristol Taurus III engine.

V.L. just didn't have experience with high speed aircraft, there wasn't any duraluminium production in Finland and nobody would sell aluminium in 1939. The Taurus engine was not available due to war and a 1,065 hp (with 87 octane fuel) Swedish-built civilian version of the Pratt & Whitney R-1830 was chosen. V.L. then decided to use the same construction system of the Fokker D.XXI. The wings and tail surfaces were made of wood/plywood and the fuselage structure was welded chrome-molybdenum steel tube with fabric and plywood coating.

The prototype was flown on 23 December 1941, manifesting serious yaw to port, excessive wing loading and engine problems. On 30 May 1942, the Department of War Supplies had placed an order for three pre-production aircraft called Myrsky I.

Built between April and June 1943, the three planes suffered accidents and two of them were destroyed, during diving tests, for fractures of the wing attachement bolts and plywood skinning under stress, due to defective bonding.

The investigation board confirmed that flutter had caused the wings to break up and recommended that they be strengthened in the forty-seven Myrsky II (525 kph) that began to be manufactured in July 1944. The fuselage fabric covering was replaced in these aircraft with plywood sheeting, the elevators and the landing gear were strengthened and a VLS 8002 constant-speed propeller (with wooden blades and cooling fan) was installed. The construction of the Myrsky II complicated when the availability of the German Tego-film glue ended, after the destruction of its manufacturing plant in 1943. It was replaced by bad Finnish glues based on casein.
Maximum permissible diving speed was raised to 650 kph and maximum engine revolutions were restricted to 3,060 r.p.m. The armament consisted of four 12.7 mm VKT LKk/42 machine guns.

The Myrsky II entered service with Ilmavoimat in July 1944, being used mainly in reconnaissance missions.

In August and September, the Myrsky II fought against two Yak-7, three Yak-9 and two La-5 of the 195 IAP, damaging several of them but without achieving any victory before ceasefire. Until being retired from service, on February 1948, the Myrsky fighters had suffered a total of 51 accidents, with the loss of 21 aircrafts and four pilots.

V.L. Pyörremyrsky (522 kph).​

At the end of 1942, the V.L. tried to negotiate a full reparation license for the Messerschmitt Bf 109 G-2, but complete sets of drawings and tools were never delivered.

The Ilmavoimat had been particularly concerned with the debut in some numbers of the Lavockin La-5 Soviet fighter and the possibility of the Germans to suspend the supply of fighters. The Pyörremyrsky programme began when the Ilmavoimat ordered two new Finnish fighters into design phase: Pyörremyrsky and Puuska.

The design was given the following basic parameters:

At least 50 km/h faster of the fastest enemy bomber
If faster than enemy fighters, it may be less agile and worse climber
If slower than enemy fighters, it must be better climber and more agile

By early 1943, V.L. was instructed to design a single-seat fighter powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving a VDM three-bladed airscrew. Since it was impossible to import aluminium due to the war, the Pyörremyrsky should be built using only domestic materials, incorporating the lessons learned from the construction of the Myrsky.

The single-spar wing was built in wood/plywood, with metal-framed, fabric-covered ailerons and electrically-operated metallic flaps. The tail assembly was also built in a similar way with metal-framed movable surfaces. The forward fuselage structure was welded chrome-molybdenum steel tube, and the aft fuselage was a Soviet-style wooden monocoque structure. The armament consisted of one engine-mounted 20 mm MG 151 cannon and two 12.7 mm LKk / 42 machine guns in the nose.

Prototype construction was low, affected by the unavailability of the German Tego-film glue and the airplane was still not completed in September 1944, when the peace treaty was signed. On 21 November 1945 during their flight testings the new fighter proved to be more manoeuvrable than the Bf 109 G-6, with an outstanding climb rate and few teething troubles.

Unfortunately, the series production was dismissed because of the difficulty in obtaining a supply of Daimler-Benz engines.

V.L. Puuska (650 kph)​

In the fall of 1943, V.L. was instructed to design a single-seat lightweight fighter, with narrow-track undercarriage, powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving three-bladed VDM airscrew.

The design should adapt to the new fighter tactics of the Ilmavoimat, which was considered outdated the dog fight, preferring the ‘zoom and climb’ to either repeat the attack, or break off the contact with an advantage in speed and climb. To meet the specification, it was necessary to design a light airframe to take full advantage of the 1,475 hp of the available engine.

The result was the Puuska, an 80 per cent smaller and light version of Pyörremyrsky that V.L. offered to the Ilmavoimat at the end of 1943. Out of the five proposed designs, the Finnish Air Force Material and Procurement staff selected two on 24 January 1944, called PM-3 and PM-5, to be built as prototypes that were to be ready on 1 July 1945. The PM-3 should use the under nose oil cooler and two radiators from Bf 109 G-2 under the wings, local manufacture Sperry artificial horizon, Hollsman compass and Vaisala reflector gunsight.

The double-joint undercarriage retraction system would use Siemens and Stromberg electrical motors and two 660 x 160 mm wheels from Bf 109 G-2. The proposed armament was one engine-mounted 20 mm MG 151 cannon, with 300 rounds, and two 12.7 VKT LKk/42 mm nose-mounted machine guns.

Wingspan: 9.2 m, length: 7.5 m, wing area: 13.5 sq.m, maximum weight: 3,200 kg, maximum speed: 620 kph, climb rate: 6.2 min to 6,000 m., service ceiling: 12,000 m.

The PM-5 was designed as a point-defence interceptor, very fast and with amazing climb rate. To save weight they decided not to install armour and the armament was reduced to a MG 151 with 210 rounds. The internal fuel was also reduced to only 400 litres, with the possibility of carrying two drop tanks of 140 litres each under the wings.

Oil and glycol radiators were grouped in a ventral nacelle to save drag.

It was expected that series aircraft were equipped with a Telefunken FuG-7a R/T device and used the main wheels from Soviet LaGG-3 and the retractable tail wheel from DB-2 bomber. The building system should be the same used in the Pyörremyrsky, but the project was cancelled on March 1944 due the low availability of DB engines.

Maximum weight: 2,650 kg, maximum speed: 682 kph, climb rate: 4.7 min to 6,000 m, service ceiling: 14,000 m.

V.L. Humu (430 kph)​

In October 1942, the Ilmavoimat placed an order with the V.L. for four prototypes of the Humu, a copy of the Brewster 239 fighter that should be built in wood/plywood/steel with the same technique used in the Fokker D.XXI. It was expected to build a series of 55 aircraft, using instrument and M-63 engines from captured Soviet airplanes.

On 8 August 1944, the prototype was flown, powered by a 930 hp Shvetsov M-63, reaching the 420 kph. A surplus Brewster fuselage and new wings built in wood/plywood by V.L. had been used for its construction. It turned out to be too heavy (2,895 kg) manifesting problems of longitudinal stability, and the initiation of series production was delayed pending results of flying tests. The proposed armament were three 12.7 mm LKk / 72 machine guns.

The project was cancelled in the summer of 1944.

Fokker D.XXI modified​

Earlier, in 1939, the Finns had experimentally fitted two underwing 20 mm Oerlikon cannons in the Fokker FR-76.

On 29 January 1940 the FR-76 shoot down a Soviet DB-3M bomber with just 18 rounds, but the excessive weight limited its performances and the experiment was discontinued.

Another attempt to improve the outdated fighter consisted in installing a modified wing (the so-called E-wing) in the FR-121. It had more dihedral and was more tapered that the standard wing.

During flight tests it was found that the gun access panel blew off as a result of the air pressure in the gun bay.

Finally, two Fokkers were modified with a retractable landing gear: the FR-117 (Mercury) on 27 April 1941, and the FR-167 (Twin Wasp) on 2 March 1942. Both aircraft were later equipped with a fixed gear, and the whole idea was dropped because the speed improvement was only 15-37 kph, depending of altitude.

V.L. Vihuri​

In 1943 the Finns were waiting to receive two crashed British de Havilland Mosquito, requested from Germany to serve as models for planned production. One would be repaired and another one would be teared into parts to make blueprints. The Finns are great wood workers and probably would have been able to circumvent the unavailability of balsa and Tego-film, with the technique used by the Soviets in the construction of the Polikarpov I-16, which already had been tested in the Pyörremyrsky. The Polikarpov fuselage was built in two halves, like the Mosquito, and each half comprised pine frames and longerons. The monocoque skin was produced from layers of birch strips glued cross-grained and molded on a former.

The new aircraft, called Vihuri, would have possibly been used as fighter-bomber with nose-mounted machine guns. It would have been powered by two 1,475 hp German Daimler-Benz DB 605 AC engines and used the landing gear of the Bristol Blenheim. It was estimated that its performances would have been inferior to those of the Mosquito because of its greater structural weight. Production plans would have delivered between mid of 1946 and December 1947, due to the overload of work that represented for V.L. the repair of fighters in service, the production of the Myrsky and the Mörkö-Moraani conversion.

Mörkö Moraani (525 kph)​

Starting from June 1944, forty-one Moranes were re-engined with one 1,100 hp Klimov (Hispano-Suiza) M-105 P driving one VISh-61P constant speed airscrew.

Only three modified aircraft entered combat during the Continuation War, shooting down one La-5 and two Airacobra.

Armament: one engine mounted 20 mm MG 151 cannon and two wing-mounted 7.7 mm (belt feed) Browning machine guns.

Do you know about the VL Myrsky III?

 

[Justo Miranda]

Finnish Fighters​

Ilmailuvoimain Lentokonethdas - IVL (Aviation Force Aircraft Factory) made under license, between 1922 and 1925, hundred-and-twenty Hansa-Brandenburg W.33 floatplanes, thirty-four Caudron C.60 and six Morane-Saulnier M.S.50c

The first indigenous fighter, the prototype IVL C.24, with parasol wing inspired by Morane designs, was flown on 16 April 1924 and the C.25, an improved version with narrower-chord wing, was flown on June 1925. Both models suffered longitudinal stability problems caused by the excessive weight of the Siemens Sh 3A engine. Its serial production was dismissed after an accident suffered by the C-25

The next attempt to provide the Ilmailuvoimat with an indigenous fighter was the IVL D-26 Haukka. The biplane prototype was flown on 17 March 1927, manifesting structural faults and flat spin tendence. Both problems were not fully resolved in its successor D-27 Haukka II and its production was again dismissed in favor of licence-built Gloster Gamecock Mk.II.

In 1928 the IVL became Valtion Lentokonetehdas-V.L. (State Aircraft Factory). Before the war, V.L. had built some self-designed trainers and second line aircrafts: it produced thirty-three units of the Saaski reconnaissance airplanes in 1928, seven Kotka light bombers in 1930, thirty-one Tuisku advanced trainers in 1933, twenty-four Viima elementary trainers in 1935 and forty-one Pyry advanced monoplane trainers in 1939, but no fighters.

V.L. Myrsky (470 kph)​

On 8 June 1939, the Ministry of Defence instructed V.L. to design a new single-seat fighter powered by a Bristol Taurus III engine.

V.L. just didn't have experience with high speed aircraft, there wasn't any duraluminium production in Finland and nobody would sell aluminium in 1939. The Taurus engine was not available due to war and a 1,065 hp (with 87 octane fuel) Swedish-built civilian version of the Pratt & Whitney R-1830 was chosen. V.L. then decided to use the same construction system of the Fokker D.XXI. The wings and tail surfaces were made of wood/plywood and the fuselage structure was welded chrome-molybdenum steel tube with fabric and plywood coating.

The prototype was flown on 23 December 1941, manifesting serious yaw to port, excessive wing loading and engine problems. On 30 May 1942, the Department of War Supplies had placed an order for three pre-production aircraft called Myrsky I.

Built between April and June 1943, the three planes suffered accidents and two of them were destroyed, during diving tests, for fractures of the wing attachement bolts and plywood skinning under stress, due to defective bonding.

The investigation board confirmed that flutter had caused the wings to break up and recommended that they be strengthened in the forty-seven Myrsky II (525 kph) that began to be manufactured in July 1944. The fuselage fabric covering was replaced in these aircraft with plywood sheeting, the elevators and the landing gear were strengthened and a VLS 8002 constant-speed propeller (with wooden blades and cooling fan) was installed. The construction of the Myrsky II complicated when the availability of the German Tego-film glue ended, after the destruction of its manufacturing plant in 1943. It was replaced by bad Finnish glues based on casein.
Maximum permissible diving speed was raised to 650 kph and maximum engine revolutions were restricted to 3,060 r.p.m. The armament consisted of four 12.7 mm VKT LKk/42 machine guns.

The Myrsky II entered service with Ilmavoimat in July 1944, being used mainly in reconnaissance missions.

In August and September, the Myrsky II fought against two Yak-7, three Yak-9 and two La-5 of the 195 IAP, damaging several of them but without achieving any victory before ceasefire. Until being retired from service, on February 1948, the Myrsky fighters had suffered a total of 51 accidents, with the loss of 21 aircrafts and four pilots.

V.L. Pyörremyrsky (522 kph).​

At the end of 1942, the V.L. tried to negotiate a full reparation license for the Messerschmitt Bf 109 G-2, but complete sets of drawings and tools were never delivered.

The Ilmavoimat had been particularly concerned with the debut in some numbers of the Lavockin La-5 Soviet fighter and the possibility of the Germans to suspend the supply of fighters. The Pyörremyrsky programme began when the Ilmavoimat ordered two new Finnish fighters into design phase: Pyörremyrsky and Puuska.

The design was given the following basic parameters:

At least 50 km/h faster of the fastest enemy bomber
If faster than enemy fighters, it may be less agile and worse climber
If slower than enemy fighters, it must be better climber and more agile

By early 1943, V.L. was instructed to design a single-seat fighter powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving a VDM three-bladed airscrew. Since it was impossible to import aluminium due to the war, the Pyörremyrsky should be built using only domestic materials, incorporating the lessons learned from the construction of the Myrsky.

The single-spar wing was built in wood/plywood, with metal-framed, fabric-covered ailerons and electrically-operated metallic flaps. The tail assembly was also built in a similar way with metal-framed movable surfaces. The forward fuselage structure was welded chrome-molybdenum steel tube, and the aft fuselage was a Soviet-style wooden monocoque structure. The armament consisted of one engine-mounted 20 mm MG 151 cannon and two 12.7 mm LKk / 42 machine guns in the nose.

Prototype construction was low, affected by the unavailability of the German Tego-film glue and the airplane was still not completed in September 1944, when the peace treaty was signed. On 21 November 1945 during their flight testings the new fighter proved to be more manoeuvrable than the Bf 109 G-6, with an outstanding climb rate and few teething troubles.

Unfortunately, the series production was dismissed because of the difficulty in obtaining a supply of Daimler-Benz engines.

V.L. Puuska (650 kph)​

In the fall of 1943, V.L. was instructed to design a single-seat lightweight fighter, with narrow-track undercarriage, powered by one 1,475 hp Daimler-Benz DB 605 AC engine driving three-bladed VDM airscrew.

The design should adapt to the new fighter tactics of the Ilmavoimat, which was considered outdated the dog fight, preferring the ‘zoom and climb’ to either repeat the attack, or break off the contact with an advantage in speed and climb. To meet the specification, it was necessary to design a light airframe to take full advantage of the 1,475 hp of the available engine.

The result was the Puuska, an 80 per cent smaller and light version of Pyörremyrsky that V.L. offered to the Ilmavoimat at the end of 1943. Out of the five proposed designs, the Finnish Air Force Material and Procurement staff selected two on 24 January 1944, called PM-3 and PM-5, to be built as prototypes that were to be ready on 1 July 1945. The PM-3 should use the under nose oil cooler and two radiators from Bf 109 G-2 under the wings, local manufacture Sperry artificial horizon, Hollsman compass and Vaisala reflector gunsight.

The double-joint undercarriage retraction system would use Siemens and Stromberg electrical motors and two 660 x 160 mm wheels from Bf 109 G-2. The proposed armament was one engine-mounted 20 mm MG 151 cannon, with 300 rounds, and two 12.7 VKT LKk/42 mm nose-mounted machine guns.

Wingspan: 9.2 m, length: 7.5 m, wing area: 13.5 sq.m, maximum weight: 3,200 kg, maximum speed: 620 kph, climb rate: 6.2 min to 6,000 m., service ceiling: 12,000 m.

The PM-5 was designed as a point-defence interceptor, very fast and with amazing climb rate. To save weight they decided not to install armour and the armament was reduced to a MG 151 with 210 rounds. The internal fuel was also reduced to only 400 litres, with the possibility of carrying two drop tanks of 140 litres each under the wings.

Oil and glycol radiators were grouped in a ventral nacelle to save drag.

It was expected that series aircraft were equipped with a Telefunken FuG-7a R/T device and used the main wheels from Soviet LaGG-3 and the retractable tail wheel from DB-2 bomber. The building system should be the same used in the Pyörremyrsky, but the project was cancelled on March 1944 due the low availability of DB engines.

Maximum weight: 2,650 kg, maximum speed: 682 kph, climb rate: 4.7 min to 6,000 m, service ceiling: 14,000 m.

V.L. Humu (430 kph)​

In October 1942, the Ilmavoimat placed an order with the V.L. for four prototypes of the Humu, a copy of the Brewster 239 fighter that should be built in wood/plywood/steel with the same technique used in the Fokker D.XXI. It was expected to build a series of 55 aircraft, using instrument and M-63 engines from captured Soviet airplanes.

On 8 August 1944, the prototype was flown, powered by a 930 hp Shvetsov M-63, reaching the 420 kph. A surplus Brewster fuselage and new wings built in wood/plywood by V.L. had been used for its construction. It turned out to be too heavy (2,895 kg) manifesting problems of longitudinal stability, and the initiation of series production was delayed pending results of flying tests. The proposed armament were three 12.7 mm LKk / 72 machine guns.

The project was cancelled in the summer of 1944.

Fokker D.XXI modified​

Earlier, in 1939, the Finns had experimentally fitted two underwing 20 mm Oerlikon cannons in the Fokker FR-76.

On 29 January 1940 the FR-76 shoot down a Soviet DB-3M bomber with just 18 rounds, but the excessive weight limited its performances and the experiment was discontinued.

Another attempt to improve the outdated fighter consisted in installing a modified wing (the so-called E-wing) in the FR-121. It had more dihedral and was more tapered that the standard wing.

During flight tests it was found that the gun access panel blew off as a result of the air pressure in the gun bay.

Finally, two Fokkers were modified with a retractable landing gear: the FR-117 (Mercury) on 27 April 1941, and the FR-167 (Twin Wasp) on 2 March 1942. Both aircraft were later equipped with a fixed gear, and the whole idea was dropped because the speed improvement was only 15-37 kph, depending of altitude.

V.L. Vihuri​

In 1943 the Finns were waiting to receive two crashed British de Havilland Mosquito, requested from Germany to serve as models for planned production. One would be repaired and another one would be teared into parts to make blueprints. The Finns are great wood workers and probably would have been able to circumvent the unavailability of balsa and Tego-film, with the technique used by the Soviets in the construction of the Polikarpov I-16, which already had been tested in the Pyörremyrsky. The Polikarpov fuselage was built in two halves, like the Mosquito, and each half comprised pine frames and longerons. The monocoque skin was produced from layers of birch strips glued cross-grained and molded on a former.

The new aircraft, called Vihuri, would have possibly been used as fighter-bomber with nose-mounted machine guns. It would have been powered by two 1,475 hp German Daimler-Benz DB 605 AC engines and used the landing gear of the Bristol Blenheim. It was estimated that its performances would have been inferior to those of the Mosquito because of its greater structural weight. Production plans would have delivered between mid of 1946 and December 1947, due to the overload of work that represented for V.L. the repair of fighters in service, the production of the Myrsky and the Mörkö-Moraani conversion.

Mörkö Moraani (525 kph)​

Starting from June 1944, forty-one Moranes were re-engined with one 1,100 hp Klimov (Hispano-Suiza) M-105 P driving one VISh-61P constant speed airscrew.

Only three modified aircraft entered combat during the Continuation War, shooting down one La-5 and two Airacobra.

Armament: one engine mounted 20 mm MG 151 cannon and two wing-mounted 7.7 mm (belt feed) Browning machine guns.

Do you know about the VL Myrsky III?

Sorry but I have no information about the Myrsky III

 

[Grey Havoc]

Just to be clear, neither the Tiira nor the Viri have anything to do with V.L. Indeed the Karhumäki factory would not be merged into V.L.'s successor, Valmet, until 1963.

So if the factory wasn't merged with Valtion lentokonetehdas during the Second World War, then which state company did it get merged into?

 

[Apophenia]

Just to be clear, neither the Tiira nor the Viri have anything to do with V.L. Indeed the Karhumäki factory would not be merged into V.L.'s successor, Valmet, until 1963.

So if the factory wasn't merged with Valtion lentokonetehdas during the Second World War, then which state company did it get merged into?

It is a bit convoluted ... Just prior to the War, Mannerheim wanted Finnish industry to decentralize. In the Autumn of 1938, Niilo and Valto Karhumäki were using their aerial photography skills to survey possible aircraft plant locations with potential for nearby airfields. They concluded that Kuorevesi in the Pirkanmaa region of western Finland was ideal.

The Brothers identified a logical spot just outside Kuorevesi for a new airfield. And nearby Lake Kuorevesi would suit float-flying (or Winter ski operations off the ice). Kuorevesi was reasonably far from the then-Soviet border. And, most importantly, Kuorevesi wasn't a major industrial town - thereby addressing objections to V.L. relocating to Tampere in 1936 (Mannerheim being convinced that Tampere would become a target of Soviet bombing in a war).

In June 1939, an agreement was reached with the Ministry of Defense for the construction of a new aircraft factory for Veljekset Karhumäki Oy in Kuorevesi. But, shortly afterwards, another aircraft facitlity was also started nearby in an effort to decentralize V.L. activities from Tampere. Production began at VL2 - the V.L. Kuorevesi plant in 1941. Then, at some point during the Continuation War, V.L. expanded its wartime activities into the adjacent Veljekset Karhumäki facility. So, V.L. was actually running two operations at Kuorevesi during the War.

So, as near as I can tell, V.L. had taken control of the Brothers' Kuorevesi building during the War but had not actually absorbed Veljekset Karhumäki Oy into their operations. Instead, the Veljekset Karhumäki plant supplied parts. Meanwhile, aircraft production was broadening in Finland. Actual airframe production was dispersed by type to various locations (for V.L., Fokkers were assembled at Kolho; Myrsky at Linnavuori (later an engine plant); Pyrys were made at Pori and Viiala; etc.).

When the war ended, the Karhumäki brothers' Kuorevesi plant was taken over completely. But, AFAIK, not Veljekset Karhumäki Oy which branched out into a small domestic airline Karhumäki Airways (Karair) amongst other things. In the meantime, V.L. - along with other defence industries - was absorbed into VMT (Valtion Metallitehtaat) the State Metal Factories (aka ValMet). VMT, in turn, became the limited company Valmet Oy in 1951 (officially 01 Jan 1952). Under Valmet Oy, aviation operations became Valmet Lentokoneteollisuus (Valmet Aircraft Industries). Ironically, in 1967, all Valmet aviation activities were centred on Kuorevesi.

Of course, all of this is second-hand and relying heavily upon machine translation. Any native Finns care to weigh in?

 

[Justo Miranda]

Fokker D.XXI with retractable landing gera

 

[perttime]

VL did two different D.XXI installations with retracts. The first one didn't function well and didn't increase performance much. The second installation actually worked and increased speeds. Neither went into production.

Not sure where I got that. Could be the Finnish History of VL book that has been mentioned in this thread.

 

[Justo Miranda]

Fokker D.XXI modified

​

Earlier, in 1939, the Finns had experimentally fitted two underwing 20 mm Oerlikon cannons in the Fokker FR-76.

On 29 January 1940 the FR-76 shoot down a Soviet DB-3M bomber with just 18 rounds, but the excessive weight limited its performances and the experiment was discontinued.

Another attempt to improve the outdated fighter consisted in installing a modified wing (the so-called E-wing) in the FR-121. It had more dihedral and was more tapered that the standard wing.

During flight tests it was found that the gun access panel blew off as a result of the air pressure in the gun bay.

Finally, two Fokkers were modified with a retractable landing gear: the FR-117 (Mercury) on 27 April 1941, and the FR-167 (Twin Wasp) on 2 March 1942. Both aircraft were later equipped with a fixed gear, and the whole idea was dropped because the speed improvement was only 15-37 kph, depending of altitude.

 

[Apophenia]

Earlier, in 1939, the Finns had experimentally fitted two underwing 20 mm Oerlikon cannons in the Fokker FR-76...​

Actually, the Oerlikon FF installation wasn't a Finnish modification. FR-76 was one of seven I-sarja D.XXIs built by Fokker. Only FR-76 was delivered with cannons, the other six I-sarja aircraft had 7.7 mm Vickers machine guns fitted (although, reportedly, all I-sarja wings were made to accommodate Oerlikons).

 

[Raa]

Does anyone know more about the relationship between VL Pyorremyrsky and VL puuska?

 

[tomi]

Do you know about the VL Myrsky III?

VL Myrsky III 10 aircraft production planned, canceled. Shvetsov M-63 engine. The parts manufactured before the production of the series was discontinued were used for the benefit of the Myrsky II series.

• Keskinen, Kalevi; Stenman, Kari & Niska, Klaus: Suomen ilmavoimien historia 14 – Suomalaiset hävittäjät. AR-Kustannus ky, 1990. ISBN 951-95821-0-X

 

[Apophenia]

I'm not sure of its veracity, but Ive read that up to 90 x Myrsky III were considered as early as October 1942 - in contest with the Humu. Presumably, by that date, VL had already secured 90 x captured Soviet M-63s from German war-booty stocks.

Somehow that turned into the 16 March 1944 order for only 10 x Myrsky IIIs. I'm guessing that the Ilmavoimat was concerned about diminished performance resulting from the larger frontal area of the Shvetsov engine.