Messerschmitt Me.262. Part two. - More prototypes

The Messerschmitt V6 was the sixth prototype. It featured a fully retractable tricylce undercarriage which was present in every subsequent version as it fixed the turbulence problems at take-off.
Testing flights continued all over 1942, but the engines proved to be problematic as the Junkers Jumo 004 was just marginally better than the BMW 003. The airframe was ready and tested by late 1942 but the lack of engines delyaed its mass production until 1944 and even then, deliveries were low with only 28 Me.262s in June, 59 in July and only 20 in August.
During the summer 1943 the Jumo 004A engine was counting with over 100 test-hours, with a time between overhauls of 50. Anyway, it proved not suitable for mass production due to its size and weight and its need of strategical materials like nickel, copper and molybdenum which were running short. Therefore, the Jumo 004B was designed to take as minimum amount of strategic materials as possible. Every heat-resistant metal parts, including the combustion chamber, were changed to mild steel and included an aluminium coating to give protection against oxidation. The whole engine represented a design compromise to minimize the use of strategic materials and simplify manufacture. With lower-quality steels of the Jumo 004B the engine required overhaul just after 25 hours for metallurgical test on the turbine. If the test was passed, it required an additional 10 hours run-test making it 35 hours the absolute limit for the turbine test.
When BMW's and Junkers' axial compressor turbojet engines were characterized by a sophisticated design that could offer a considerable advantage, the lack of rare materials put it into disadvantage when compared to the 'partly axial-flow' of both British and American jet engines which in spite of their simpler design, they had a longer operational life span. Sir Frank Whittle, pioneer of British turbojet technology, concludes in one of his report that "it was in the quality of high temperature materials that the difference between German and British was most marked".
The aircraft could carry 2000L of fuel (440imp gall/530 US gall) in two 900L tanks, one each fore and aft of the cockpit plus an additional 200L ventral fuselage tank beneath. The expected flight endurance of the Me.262 was of 60-90 minutes. It was operated on J2 fuel (which was derived from brown coal), with the option of diesel and the option of oil and high octane B4 aviation petrol. As the fuel consumption doubled the rate of any typical twin-engined fighter of the era, a low-fuel warning indicator was placed in the cockpit that remained pilots when the fuel amount was below 250L.
The Messerschmitt Me.262 V8 was the first one to be armed with four 30mm Mk.108 cannons in the nose.
The Me.262 V9 was the ninth prototype which was used as a test platform for both communications gear and electrically operated acoustic homing and detection devices. It was probably used to examine the adaptation into a night-fighter. On 1st October 1944 it was fitted with a new streamlined canopy and tests gave excellent aerodynamical improvements over the regular versions which were already at the frontlines. However, it came too late to make any impact in the war.
The Me.262 V-10 was a bomber prototype with a towed bomb which would be the prototype for the bomber variants of the Me.262.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Me_262
2. https://www.valka.cz/Messerschmitt-Me-262-t15721 (translated)
3. http://www.luftwaffe39-45.historia.nom.br/aero/me262.htm (translated)
4. The Me.262 Stormbird: From the pilots who flew, fought and survived it.
5. Salamander Books - The Complete Book of Fighters

Messerschmitt Me.262. Part one - first prototypes

The Messerschmitt was world's first operational jet fighter-bomber. Design work started before the World War II began but various problems delayed the project.
In 1939 the RLM issued a specification for a jet powered aircraft with one hour of endurance and a speed of at least 850km/h (530mph). Messerschmitt overtook the task and appointed Dr. Valdemar Voigt to lead the design team with Robert Lusser overseeing.
First plans were drawn in April 1939 and the original drawings were very different from the aircraft that eventually entered service, as it featured root-mounted engines instead of the podded ones. Plans were submitted in June 1939 and progression of the original design was greatly delayed by technical issues involving the new jet engine. As the engines were slow to arrive, the design was changed from root wings to underwing pods, allowing them to be changed and repaired faster if needed. As the BMW 003 engines were heavier than expected, the wings were swept slightly by 18.5º to acommodate a change in the centre of gravity. Messerschmitt also had to face another trouble, the lack of funding, as many high ranking officers thought that the war could be won with conventional aircrafts. Among them were Hermann Göring who cut the engine development to just 35 engines in February 1940. However, both Willy Messerschmitt and Adolf Galland supported Messerschmitt and by 1941 the first prototype was ready to flight.
The first prototype, named V1, flew on 18th April 1941 and, since the BMW 003 engines weren't available, it was powered by a single conventional Junkers Jumo 210 mounted in the nose and driving a two-bladed propeller. It was used to test the V1's airframe. Later, when the BMW 003 engines were available, they were installed in underwing pods but retaining the Junkers Jumo 210 just in case. This decission proved wise as the jet engines catched fire during the test flight and the pilot had to land using the propeller engine alone. The first four prototypes featured a convetional landing gear with a retracting tailwheel.
The third prototype became a real jet fighter when it flew on 18th July 1942 in Leipheim, close to Günzburg, however its conventional retracting tail wheel gear caused the jet exhaust to deflect off the runway with the wing's turbulence negating the effects of the elevators and the first takeoff attempt was cancelled. On a second attempt, the problem was solved by tapping the aircraft's brakes at takeoff speed, lifting the horizontal tail out of the wing's turbulence. In order to avoid that problem for good, the fifth prototype featured a tricycle landing gear which would feature in every production aircraft.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Me_262
2. https://www.valka.cz/Messerschmitt-Me-262-t15721
3. Salamander Books - The Complete Book of Fighters

Villish VM-6

Today's airplane is a curious Russian project that didn't see the light.
In mid-1917, the concept of a high-speed flying-boat came to an end and it was then when the 2nd Cpt. Scherbachev had the idea of designing a "counter-fighter". It was going to be a land-based single-engined aircraft with dropable wheeled gear to make it able to land on water surfaces. The idea also featured a blocking mechanism to stop the propeller and block it at the horizontal position when the airplane touched the water, turning the engine off.
In summer 1917 the UMA (Uprelevnie Morskoj Aviatsii - Naval Aviation Management) gave green light to this project and named it "Counter-Fighter". It's study and completion was ordered to D.P. Grigorovich, AIS Design Bureau and A.Yu Villish being this last one the only one who could present complete project winning the contest as the other two contestants retired from it.
On 13th September 1917 the project was ready. It was going to be powered by a 200hp Hispano engine and armed with a single Vickers 0.303in placed on the nose. The designs made by Villish included also a catapult for launching, rails, undercarriage and a compressed air system. The construction of the prototype started in the end of 1917 and by spring 1918 the prototype was almost finished as the waterproof boat-shaped fuselage, covered in plymouth which was going to be the fuselage was completed with the tail section (which was very thin and it's believed that it wouldn't have cope very well with the design) also completed but not ensambled.
The only incomplete prototype was destroyed during the Russian Civil War. The war in 1918 didn't allow A. Yu. Villish to finish the project and, as he was a landlord, he fleed Russia and settled in the Baltic Coast (surviving the Russian Civil War). He never returned to aircraft design and construction.

Sources:
1. http://ram-home.com/ram-old/vm-6.html
2. https://www.secretprojects.co.uk/forum/index.php?topic=10533.0
3. http://www.airwar.ru/enc/fww1/vm6.html (translated)

Aero L-29 part seven, miscellaneous users

As we've posted previously so many times, the Aero L-29 was used by many countries. Now it comes the turn for those miscellaneous and civilian users which we haven't counted for tags as they were too many of them.

• People's Republic of China: The People's Liberation Army Air Force bought 4 Aero L-29 in 1968. We found some photos of an Aero L-29 kept nowadays in the Beijing's Air Museum, however, as we couldn't find pics of the L-29 serving with the PLAAF, the drawing should be considered as speculative.
• Indonesia: The Indonesian Air Force bought some L-29s in the late 1960s to equip their trainer squadrons. They were in active service until the 2000s when they were retired and sent to the Indonesian Air Force Museum where they are being shown nowadays.
• Socialist Republic of Vietnam: It seems that the Vietnam People's Air Force had some L-29s in trainer service after the end of the Vietnam War. They were replaced with the more advanced L-39, and nowadays at least one L-29 is being shown at the Bach Mai Air Force Museum.
• United States: The US Navy got some modernized Aero L-29 during the late 2000s to use them in aggressor squadron maneouvres. They were seen on board the USS Bonhomme Richard (LHD-6) back in the year 2010.
• Argentina (untagged): The Argentinean Experimental Aircraft Association has one L-29. 
• Canada (untagged): The International Test Pilots School uses the Aero L-29.
• Norway (untagged): The Norwegian acrobatic team "Russian Warbirds of Norway" use the L-29 (with British civilian registrations).
• New Zealand (untagged): The acrobatic team Soviet Star, based in Christchurch, is equipped with the L-29.
• Slovakia (untagged): The Slovakian company Air Prestige has at least one Aero L-29.

We know there are many more civilian users, but we selected some of them.

Sources:

1. https://en.wikipedia.org/wiki/Aero_L-29_Delfín

2. https://en.wikipedia.org/wiki/People%27s_Liberation_Army_Air_Force

3. https://en.wikipedia.org/wiki/Indonesian_Air_Force

4. https://en.wikipedia.org/wiki/Vietnam_People%27s_Air_Force

5. https://forum.keypublishing.com/forum/modern-military-aviation/naval-aviation/103773-l-29-over-lhd-6

Aero L-29 part six, African and Middle-east users

As we've said previously, the Aero L-29 was exported to an enormous amount of countries. Here are some of them:

• Democratic Republic of Afghanistan (DRA): Apparently, when the USSR invaded Afghanistan and created the DRA, they received a small amount of Aero L-29s together with some L-39s. As we couldn't find any graphical evidence of this, the drawing should be considered as speculative.
• United Arab Republic/Egypt: The United Arab Republic's Air Force received the Aero L-29 in 1959. It was the main trainer of the Egyptian Air Force during the 1960s and it was used in active combat role during the Yom Kippur War of 1973 when some of them were armed with missile launchers and sent to attack Israeli ground forces. It served as their main trainer until the late 1970s when it was replaced by the more advanced Aero L-39.
• Iraq: It seems that some Aero L-29s were delivered to Iraq after the 1958 coup d'etat that overthrew the King of Iraq. The L-29s served with the 2nd Training Squadron at the Tikrit Air Force Base during the 1960s until they were phased out by the more advanced Aero L-39.
• Libya: Some sources claim that the Libyan Arab Jamahiriya (Gaddafi's Libya) received some Aero L-29s to equip the air force. As we couldn't find graphical evidences or even text references, the drawing should be considered as speculative as most probably only the L-39 served in Libya and not the L-29.
• Mali: Just like in the Libyan case, it seems that the Malian Air Force bought some L-29s in the mid-1960s to equip their air force. Apparently they served during the 1960s, however as we couldn't find neither graphical nor text evidence, the drawing should be taken as speculative.
• Syria: It seems that the Syrian Air Force was supplied with some Aero L-29s in the very late 1950s and served through the 1960s. Most of them were either destroyed in the Six-Days war and those that survived, served until the 1970s when they were replaced by some other more modern type like the Aero L-39.

Sources:

1. https://en.wikipedia.org/wiki/Aero_L-29_Delfín

2. https://en.wikipedia.org/wiki/Democratic_Republic_of_Afghanistan#Air_Force

3. https://en.wikipedia.org/wiki/Egyptian_Air_Force

4. https://en.wikipedia.org/wiki/Iraqi_Air_Force

5. https://en.wikipedia.org/wiki/Armed_Forces_of_the_Libyan_Arab_Jamahiriya

6. https://en.wikipedia.org/wiki/Mali_Airforce

7. https://en.wikipedia.org/wiki/Syrian_Air_Force

Aero L-29, part five, African users.

The Aero L-29 saw very active service in the African continent, in the next countries, among another oner that we'll post later:

• Angola: There are six L-29s in active service nowadays with the Angolan Air Force. Those were delivered during the 1970s and used during the Angolan Civil War. After that, they were used as their main trainer, role which they keep performing nowadays in the 9th Training Squadron, based at Menongue Air Base, in Menongue, Angola.
• Ghana: Some ex-Nigerian L-29s were sold to Ghana in the late 1980s. They served from 1989 until the mid 2000s when they were replaced by the Aero L-39. 
• Guinea-Conakry: The newly founded Guinean Air Force bought some Aero L-29s from Czechoslovakia to equip their training squadron. They served for an unknown period of time when they were retired.
• Nigeria: The Aero L-29 reached Nigeria in 1967 and served through Nigerian Civil War where it was used extensively as an attack aircraft. After that, they were used as trainers until they were either retired or sold to other countries like Ghana.
• South Africa: The South African 'Tyco Dolphins' acrobatic team operated at least one Aero L-29 during the 1990s.
• Uganda: The Ugandan People's Defence Air Force has six L-29s in inventory nowadays. They were bought directly to Aero during the 1970s and were used during the Ugandan-Tanzanian war in 1978. They are kept in active service nowadays.

Sources:

1. https://en.wikipedia.org/wiki/Aero_L-29_Delfín

2. https://en.wikipedia.org/wiki/National_Air_Force_of_Angola

3. https://en.wikipedia.org/wiki/Ghana_Air_Force

4. https://en.wikipedia.org/wiki/Guinea_Air_Force

5. https://en.wikipedia.org/wiki/Nigerian_Air_Force

6. https://en.wikipedia.org/wiki/Uganda_People%27s_Defence_Force#Ugandan_People's_Defence_Air_Force

Aero L-29, part four, various European users users

As we've previously said many time, the Aero L-29 was used by many Eastern bloc countries. The ones covered in this post are:

• Hungary: As it happened with almost every other Warsaw Pact country, Hungary bought a number of Aero L-29 in the mid 1960s (in 1965 to be more precise) to equip their training squadrons. They served until the fall of communism in 1989 together with other more advanced and modern types. 
• Romania: Being a Warsaw Pact member, the Romanian Air Force was supplied with a number of Aero L-29 to equip their training squadrons and flight schools. They served until the fall of communism in 1989 and shortly beyond, together with other types.
• Slovakia: After the creation of the Slovak Air Force in 1993, there were many L-29s left in the country which served as the main trainer for the newly created air force. It served alongside the more advanced Aero L-39 until the very late 1990s when it was phased out.
• USSR: The Soviet Air Force (VVS) was the main user of the Aero L-29. It served as its main trainer, together with other types until the dissolution of the USSR in 1992.

Sources:

1. https://en.wikipedia.org/wiki/Aero_L-29_Delfín

2. https://en.wikipedia.org/wiki/Hungarian_Air_Force

3. https://en.wikipedia.org/wiki/Romanian_Air_Force

4. https://en.wikipedia.org/wiki/Slovak_Air_Force

5. https://en.wikipedia.org/wiki/Soviet_Air_Forces

Aero L-29, part three, Czech and East German users

The Aero L-29 was a jet-powered aircraft which featured a straightforward and simple design and construction. It used a mid wing with a T-tail arrangement. Wings were unswept and air intakes were placed at the wing roots. Undercarriage was reinforced and able of withstand considerable amount of stress. It was relatively unpowered but even yet, it showed many favourable characteristics in its flight performance, like handling ease. The primary flying controls were manually operated and both flaps and airbrakes were actuated using hydraulic systems.
Most of the aircraft were powered by the Czech-designed Motorlet M-701 engine which delivered 1960lb of thrust (8,7kN). Between 1961 and 1968 approximately 9250 engines were completed and no less than 5000 of them were destinated to the L-29. The student and the instructor were placed in a tandem layout underneath separate canopies with the instructor's position placed in a slightly position to better oversee the student. Both posts were provided with ejection seats which were interlinked to fire in a synchronised manner to avoid any possibility of mid-air collision between the two ejector seats.
During the mid 1990s many were sold to private owners to use them in the private civil sector with many technical changes like the removal of military related equipment such as gunsights, the replacement of avionics with western-made ones and so on.
As we said previously, the Aero L-29 was the main trainer of the Czechoslovak Air Force since the 1960s and it was kept in active use, together with the Aero L-39, until the mid-1990s when it was withdrawn from service and many of them were sold to private owners to use them in aerial shows. The type also served with the East-German Luftwaffe from the mid-1960s until the late 1980s when it was withdrawn from service.

Sources:
1. https://en.wikipedia.org/wiki/Aero_L-29_Delfín
2. https://en.wikipedia.org/wiki/Air_Forces_of_the_National_People%27s_Army
3. https://en.wikipedia.org/wiki/Czechoslovak_Air_Force