The powerful and deadly Messerschmitt Bf-109 was the mainstay of the Luftwaffe’s fighter arm throughout World War II, scoring more aerial victories than any other type. Thirteen Bf 109 pilots claimed more than 200 victories apiece, while two of these ‘Experten’, ‘Bubi’ Hartmann and ‘Gerd’ Barkhorn, each shot down more than 300 enemy aircraft. In the early years of the war, the speed, handling characteristics and firepower of the Bf 109E 'Emils' gave many Allied Hurricane and Spitfire pilots a nasty shock.
With a top speed of 690 km/h (429 mph) at 7,400 m (24,280 ft), a powerful 2,000 horsepower Daimler-Benz 605D engine and a pressurized cabin, the K-4 ‘Kurfürst’ was the best and final version of the Bf-109 to see service. Armed with one 30-mm Mk 108 cannon and two 13-mm Mk 131 machine guns, the K-4’s agility made it more than a match for most Allied fighters, while its blistering firepower made it the scourge of high-flying enemy bombers.
The ‘Kurfürst’ was also no slouch in the ground-attack role, carrying either a 500 kg or a 250 kg bomb.
Jump into your K-4, get airborne and tangle with Mustangs, Spitfires and Thunderbolts, or scythe your way down through massed Flying Fortress bomber formations.
MW-50 (MethanolWasser 50) is a 50-50 mixture of methanol and water sprayed into the Bf 109K-4's supercharger, allowing the use of increased boost pressures.
Many Bf 109 variants use some sort of boost. The G-6 was the first variant designed for a new field modification kit or Rustsatz model that allowed a large number of various standard kits to be quickly installed in the field, as well as a number of Umrutsatz, or factory kits that could be installed in the factory. The U2 kit provided for a 118-liter tank behind the cockpit used for the GM 1 nitrous oxide injection system, while the U3 kit used a tank for the MW 50 water-methanol mix.
At sea level, the engine runs at over 1800 hp with MW-50 enabled, compared to 1430 hp with the MW-50 off.
The boost provided by the MW-50 begins to decrease in power at altitudes above 6,000 meters.
The Bf 109K, as most Bf 109 variants, uses a single main 250-liter L-shaped fuel tank located partly under the cockpit floor and partly behind the rear cockpit bulkhead.
The Bf 109K-4 can also carry an external drop tank under the fuselage with the capacity of 300 liters.
The fuel system operates on a simple principle. When more than one fuel tank is used, all tanks are daisy-chained and fed into one another. A Fuel Selector lever located on the left side of the Front Dash allows the pilot to manage the system.
Two fuel pumps are provided, P1 and P2. P1 draws fuel from the rear section of the tank, while P2 draws fuel from the front of the L-shaped tank. A Fuel Cock lever located below the throttle quadrant is used to switch between the fuel pumps, with the options of ZU (both off), P1 (P1 pump), P2 (P2 pump), and P1+P2 (both).
The engine always draws fuel from the main tank.
When drop tanks are used, their fuel pump feeds the main tank. The Fuel Contents Gauge will continue to display full for as long as the drop tanks continue to feed the main tank. Once the drop tank is emptied, the fuel quantity in the main tank begins to decrease.
When drop tanks are used, the Fuel Selector Switch should be set to Hinten. The Fuel Contents Gauge will continue to display full for as long as the drop tanks continue to feed the rear and in turn the forward tanks. Once the drop tanks are emptied, the fuel quantity in the rear tank begins to decrease.
The hydraulic system in the Bf 109 is used to operate the landing gear and the wheel brakes.
The landing gear is normally raised and lowered hydraulically. There is also an auxiliary manual system for operating the gear.
The Bf 109K-4 also has hydraulically operated brake shoes on each of the two main wheels. Each has its own hydraulic pump and brake lines. Each wheel can be braked individually.
A circular oil tank is located in the nose. As no armor protection is provided for the oil system, the oil tank and the oil cooler are some of the aircraft's most vulnerable spots.
The oil system is used for the following:
The Bf 109 K-4 used two matching radiators partially recessed in the wings for cooling. First introduced during a radical redesign of the F for Friedrich variant, the system used a system of interconnected flaps to efficiently regulate cooling while providing the least possible drag. The flaps are controlled automatically by a thermostat that works to provide maximum cooling by moving the flaps in unison as needed.
The automatic system can be somewhat sluggish, especially on the ground. Common pilot tactic is to nudge the throttle slightly on take-off to reach the proper temperature limit, causing the automatic cooler flaps to open or close as needed.
Manual override for the system is also provided. It should be used in the case of emergency; during normal operation it is highly recommended to use the automatic system.
The electrical system is powered by a 2000-watt 24-volt generator. The system also contains one 7.5 Ampere-hour battery.
The electrical system powers the following:
The Circuit Breaker Panel on the right-hand side of the cockpit is used to power up the components.
Each circuit breaker has two buttons. The larger black button with a white dot switches the corresponding circuit on. Red button opens the circuit and switches it off.
Each circuit is designed to pop out if overloaded and can be reset by pushing the black button in.
The oxygen system consists of a cockpit-mounted flow valve with the attached flow monitor, the regulator unit with oxygen hose, and high-pressure lines with pressure gauge, and a set of spherical 2-liter bottles located in the right aircraft wing that contain the oxygen. The bottles are split into three banks of three as an additional safety measure.
Opening the flow valve starts the flow of oxygen. Oxygen flows to the regulator unit. The provided Flow Indicator and the Pressure Gauge located on the right-hand side of the Front Dash correspondingly indicate system status.
