Concluding the conversation about the aircraft of the 17th family of the Claudius Dornier firm, one cannot but say a few words about the reconnaissance aircraft, which represented a separate detachment, which could have good prospects. However, something went wrong ...
In general, the development of aircraft during the interwar period was strange. Mainly because not fighters, but bombers were at the forefront of development. Since this class of aircraft was not as limited in size and weight as fighters, such novelties as retractable landing gear, cantilever wings, the number of which became smaller, aerodynamic refinements, and so on began to appear en masse on bombers. As a result, some bombers began to overtake biplane fighters.
And then the concept of a "high-speed bomber" was born, which does not need to be burdened by defensive weapons... The plane will simply leave the enemy at the expense of speed.
It is clear that the idea could not but please. And the basis for the execution was taken, if not a separate project, then a passenger airliner, whose interior was simply changed to a compartment with bombs. This is how one of the main losers of the Second World War, Bristol Blenheim, the Italian Savoy-Marchetti S.79, the German Dornier 17, appeared.
The Do.17 was a very modern aircraft and was an all-metal overhead monoplane. The long, narrow fuselage had a duralumin frame and smooth metal skin. The radiators were deeply hidden inside the engine compartment of the engine nacelles, so their cross-section was small. The main landing gear in flight was completely retracted inside the nacelles, and the tail wheel was retracted into the fuselage along with the fairing.
The eighth prototype of the aircraft was built precisely as a long-range reconnaissance aircraft with the possibility of delivering a bomb strike. The plane itself was very different from its bomber counterparts in the layout of the cockpit in the light of the tasks that were posed to the scout.
If the Do.17E bomber was called a "flying pencil", then its reconnaissance brother did not look like a pencil at all.
The nose has become larger and rounded. The glazing was made more extensive for both the pilot and the navigator, who was assigned the duties of an observer. In place of the first passenger compartment of the original Do.17 version, a radio room was equipped with a radio operator's workplace and a set of radio equipment. A blister rifle installation with an MG.15 machine gun appeared above the wheelhouse, from which, if necessary, a radio operator, who also became a shooter, could repel attacks from the rear hemisphere.
It was believed that the high speed of the scout was his main trump card in the confrontation with enemy fighters, so one machine gun "just in case" would be enough.
In place of the second passenger cabin, two or three cameras were placed between the wing spars, depending on the model.
The Dornier long-range reconnaissance aircraft was named Do.17F-1. The main difference from the bomber was the absence of bomb dropping mechanisms and a bomb sight. Instead of the bomb racks, another fuel tank was installed in the compartment, and the Rb 10/18, Rb 20/30 or Rb 50/30 cameras were placed below, in the bomb positions.
The plane was "tested" in Spain during the Civil War as part of the Condor legion. 15 scouts have greatly enhanced the data mining capabilities of Franco's army.
Here it turned out that Polikarpov's I-16 fighter, although “with a screeching noise,” was catching up with Do.17. 390 km / h for the I-16 versus 355 km / h for the Do.17 is a small but advantage. Once an airplane appeared capable of catching up with a reconnaissance aircraft (or a high-speed bomber), then something must be done about it.
But it should be noted that the losses of Do.17F-1 scouts in Spain were mainly from anti-aircraft fire, which confirms the high speed qualities of the scout. During the year that the Do.17F was used as a reconnaissance aircraft, Franco's army shot down only 2 aircraft, in exchange for which the Germans politely provided 10 more aircraft of the next Do.17Р modification.
The armament had to be strengthened to three MG.15 machine guns. A course machine gun appeared, from which a pilot or navigator could shoot, and another machine gun from a radio operator, who shot back and down through a hatch in the cockpit floor.
In general, with the presence of enemy fighters in the air, the work of the radio operator ended.
Despite the obvious flaw in terms of armament and the distribution of duties between the crew members, the Do.17 liked the highest ranks of the Luftwaffe and it was decided to re-equip all reconnaissance squadrons with this aircraft. The frankly unsuccessful "Heinkel 70" had to be changed to a more modern aircraft at the time of its adoption.
Spanish combat trials confirmed the Luftwaffe leaders' belief that the Do.17F was the right fit. And work was started on the Do.17Р modification, which was the next in the development line.
The Do.17Р series went into production in 1938. The main difference was the replacement of engines with air-cooled engines from BMW. The proportion of metal in the design of the planes was increased, which gave an increase in speed. Do.17Р developed 410 km / h at 4000 m.
Due to the use of "thicker" air-cooled engines, the chassis track has increased, which cannot be called a minus. On the Do.17P, only two cameras Rb 50/30 or Rb 75/30 were installed, and the place of the third camera was taken by an enlarged gas tank. The total fuel supply for the Do.17P was 2120 liters and significantly increased the range, which was 675 km.
The armament has also undergone changes. Instead of the usual pivot turret, a lens mount was installed at the top of the fuselage. The two points for firing down and back and forward remained unchanged, but on the later Do.17P aircraft, a fourth firing point appeared, the MG.15 machine gun, which fired through the cutout in the frontal glazing of the cockpit forward and downward.
Aircraft with such a set of weapons took part in the initial stage of the Second World War.
The Do.17Р aircraft were produced until the end of 1938, until they were replaced by the next modification - Do.17Z. A total of 330 Do.17Ps were produced. For a scout, a very, very impressive figure.
It is worth noting special upgrades, the long-range naval reconnaissance Do 17P-1 / U1, which was equipped with a compartment with an inflatable lifeboat and a large emergency kit, and the Do.17P-1 / Trop, which was equipped with dust filters, desert equipment and an additional water tank. 50 liters.
On the basis of the Do.17P, an experimental series of four aircraft with water-cooled DB.601A engines with direct fuel injection was created. These were very serious machines, the maximum speed was 532 km / h, the flight range was 2250 km.
For certain reasons (the demand for DB.603 engines for fighters), the aircraft did not go into production, and four manufactured copies were placed at the disposal of the Rovel air reconnaissance special group.
The Do.17F and P scouts served in specialized squadrons until the very end of the war.
About 20 scouts were sold to Bulgaria. 12 aircraft took part in the operations of German and Italian forces in the Mediterranean Sea. Bulgarian "Dorniers" accompanied Italian and German ships going with various cargoes to North Africa, and also made aerial photography of minefields in the Aegean and Mediterranean seas.
After the "U-turn" of Bulgaria on September 8, 1944, the Bulgarian "Dorniers" together with the crews were part of the Soviet aviation, where they were used as scouts.
Is interesting история the appearance of this plane.
When the Do.17Z modification appeared, the Swedes wanted to buy this aircraft, which the French refused to fulfill the previously concluded contract for the Breguet-694 aircraft. Mistral, but in the 20th century.
The German aviation ministry gave the export permission, but to avoid confusion, gave the aircraft a new name. The Do.215a-1 was completely identical to the Do.17Z.
But the Swedes were unlucky twice, because export ban was imposed upon the readiness of a batch of 18 bombers. And these bombers were urgently converted into scouts and, under the name Do.215b-1, were included in the Luftwaffe.
Even the Do.215b-4 modification was made, in which the aircraft carried only two cameras, the Rb-50/30 was mounted under the lower gun mount, and the Rb-20/30 - on the entrance hatch. But in the compartment it was possible to hang 5 bombs of 50 kg each, and when flying over short distances - 10 such bombs.
Defensive armament consisted of two MG-15 machine guns firing forward, two of the same machine guns in the side windows of the cockpit and two machine guns in the upper and lower positions backward.
The crew was finally increased by one person and consisted of a pilot, navigator and two gunners, one of whom also served as a radio operator.
Limited production of the Do.215b continued until early 1941, with a total of 101 aircraft produced.
In 1940, our specialists bought two of these aircraft and carefully studied them at the Air Force Research Institute.
A lot of interesting things came to light. It turned out that the Germans, to put it mildly, were cunning. The maximum speed at the ground was 30 km / h less, and at an altitude of 4500 meters - by almost 50 km / h. The time to climb 3000 m was 6,2 minutes instead of the declared 5,2.
On the other hand, a set of excellent FuG-10a radio station, EZ-3 radio compass, blind landing equipment and “SAM” autopilot made this aircraft very interesting for pilots.
According to the pilots, the aircraft was easy to fly, had excellent visibility, and the equipment for "blind" and night flights allowed it to be operated at any time of the day and in adverse weather conditions.
The glazed nose contributed to an excellent view forward, downward, to the sides and back. The flight test report noted:
"With a good view and the joint location of the entire crew, the enemy can be quickly detected and the entire crew is immediately notified."
Training air battles Do.215 were conducted with I-153 and I-16 fighters. As a result, it turned out that the German aircraft was virtually defenseless in attacks from the front, bottom and front to the right, and the interaction of fire in the hemisphere of the front and rear firing points of the aircraft during attacks in the front was impossible. When the fighter leaves the attack towards the tail of the Do-215 aircraft, short-term fire from the upper rear or hatch installation is possible. The use of weapons of the upper, rear and hatch firing points is possible for all attacks in the rear hemisphere, but the firing angles of the attacking aircraft are limited.
Soviet experts gave recommendations to the pilots that "Do.215 has the most vulnerable and undefended sectors in front of the completely left lower sector and on the right above and below at angles of more than 20 degrees, as well as behind directly under the tail from the stabilizer and below - up to 25-30 degrees. In these sectors, the attacking fighter is not can be fired upon by any of the rifle installations. "
It was also noted that
“The aircraft has excellent forward visibility and excellent conditions for bombing. The performance of navigational tasks is ensured by the availability of good air navigation equipment. The Dо.215 aircraft can successfully perform reconnaissance missions both visually and using aerial photography. "
Do.215 aircraft were used as long-range reconnaissance aircraft throughout the war.
This aircraft appeared due to the fact that the aircraft designers received a new BMW 801 engine, more compact and powerful. 1580 h.p. the new engine promised a very decent increase in the characteristics of the aircraft.
The Do.217 bomber turned out to be quite good, if we exclude the fact that it was never taught to dive. With the scout, everything turned out a little differently. In general, work on reconnaissance models never stopped at the Dornier firm, and there were many projects. Do.217M-8, which did not go into production, Do.215V-6 with DB 601T engines, Do.217A-0 with DB 601R engines, Do.217L with DB 603H engines and a GM1 boost system. According to calculations, Do.217L could reach a speed of 575 km / h and gain an altitude of 15 m. The aircraft was not produced due to the lack of DB 000H engines, which despite the power of 603 hp. turned out to be very moody.
But there was a very interesting reconnaissance bomber Do.217P in preliminary production. The plane was actually three-engine, with two DB 603B engines with a capacity of 1750 hp. added inside the fuselage, in the bomb bay, a third DB 605T engine with a capacity of 1400 hp, which acted as a central pressurization unit, increasing the air pressure at the inlet to the main engines when flying at high altitude.
The idea itself is not new, it was applied here in the TB-7 / Pe-8 in the mid-30s. But the Germans managed to create a good pressurized cabin for three people, which did not work for the Soviet designers.
On trials, the Do.217PV1 easily climbed to an altitude of 11 m, and the crew did not experience any discomfort at all, which was noted in the reports. A larger wing was subsequently installed.
The Do.217P had to compete with the Henschel aircraft, the Hs.130. The development of the two companies was carried out in parallel, but the Henschel was a new generation machine and could not get on stream as quickly as the brainchild of Dornier. The final point in the programs for the creation of both aircraft was put by the allies: during the raid on Stuttgart, both prototypes of the Dornier Do.217P and both Henschel Hs.130 were destroyed.
Three pre-production Do.217P-0 aircraft were built and handed over to Rechlin for testing.
In general, it turned out interesting with them: a pressurized cabin is great, but what about machine guns? Hatch, lens, window installations for a pressurized cabin are completely unacceptable. You need a hole in the glass through which the barrel will stick out!
In general, the problem could be solved with the help of remotely controlled installations, but that was too much of a complication. Therefore, we made a compromise: Do.217Р-0 were armed with three MG.81Z pairs in standard bow, rear upper and lower settings.
When the plane reached operating altitude, the machine guns were retracted inside, and the embrasures were closed with sealed hatches. When descending, when the cockpit pressurization was not required, the embrasures opened and the weapon could be used.
It was believed (quite rightly) that at altitudes above 8 meters, the likelihood of meeting enemy fighters would be extremely small.
The Do.217Р-0 reconnaissance equipment consisted of three aerial cameras instead of two of its predecessor - one Rb 20/30 and two Rb 70/30. Since the pressurization unit was located in the former bomb bay, two suspension assemblies were equipped under the wings, on which it was possible to carry either two additional fuel tanks of 900 liters each, or two bombs of 500 kg each.
The company planned to produce two variants of the Do.217Р high-altitude reconnaissance aircraft. The first one corresponded to the Do.217Р-0, the second version of the Р-2 was distinguished by a large wing of as much as 100 sq. m.
The plans were not implemented, since at the end of the war the scouts were no longer so in demand.
In general, everything was complicated with the Dornier planes. The Do.217 was at least as good as the Ju.88 in flight performance and was definitely superior to the He.111. However, the production of Junkers and Heinkel aircraft dominated, and Dornier aircraft were built in addition. Therefore, not so many were released, only 346 reconnaissance aircraft.
On the other hand, reconnaissance aircraft are far from the most numerous class of aircraft, so here we can say that Dornier's work was quite successful. Numerous detailed photographs of the territory of the USSR captured after the war are proof of this. Thanks to these photographs, the Germans always had the most detailed maps at their disposal, and this was the undoubted merit of these aircraft.
Wingspan, m: 24,50.
Length, m: 17,85.
Height, m: 5,00.
Wing area m: 65,00.
- normal take-off: 14;
- maximum take-off: 15 980.
Engine: 2 х Daimler-Benz DB-603А (with the compressor based on DB-605Т) х 1750 hp
Maximum speed, km / h: 580.
Maximum rate of climb, m / min: 290.
Practical ceiling, m: 15 500.
Crew, person: 3.
- four 7,92 mm MG-81 machine guns - two forward, one backward in the upper and lower settings;
- two 500-kg bombs under the wing.