Archives: Gmedia Albums

Control compartments 3 showing gyro mounting platform with two gyros and DC motor driven 3 phase AC voltage generator. The alcohol tank pressurisation pipe is also shown running through the equipment bay (large silver coloured pipe). Image copyright Imperial War Museum

LEV-3 V2 missile gyroscope system with mounting plate. The third component of this system, the Muller gyroscopic accelerometer, is missing – the 2x mounting points can be seen on the right-hand side of the mounting plate.

Photo shows rare surviving complete set of 8 lead acid battery cells from one of the V2 rocket’s 32 volt (100 amp) lead acid batteries. Two sets of batteries like this were used to provide the direct current (DC) voltage used aboard the V2 missile to power the DC to 3-phase alternating current (AC) generators, that in turn, powered the gyroscopes, electro-hydraulic servos, trim motors and other vital guidance and control devices. Photo copyright: The Horst Beck Collection

Photo shows rare surviving 1.2 volt cell from the V2 missile’s 50 volt command or signalling battery used in its gyro guidance system (note, the terminal connection on the left is missing from this exhibit, it would be identical to the one on the right). This wet nickel-cadmium battery cell was combined in pairs to a total set of 21 providing a 50.4 voltage at 300mA. The cells were contained in a wooden box that was held on a rack in equipment bay III. Its function was to provide the direct current (DC) signalling voltage that communicated the moment to moment resistance of the gyroscope’s potentiometers to the analog guidance computer (Mischgerät = Mixer-device or control amplifier) aboard the V2 missile. It was critical that the signalling voltage was maintained between 48 and 50.4 volts. Photo copyright: The Horst Beck Collection

The Muller mechanical or Pendulous Integrating Gyroscopic Accelerometer – today normally referred to as a PIGA. Designed by Fritz K Muller.

The J device no1 (J Gerate Eins). The full name of this device is: the Muller Pendulous (or mechanical) Integrating Gyroscopic Accelerometer – today normally referred to as a PIGA. The device, designed by Fritz K Muller, operates as a switch to initiate rocket engine shutdown and is able to smoothly record and accumulate every moment of acceleration, without any kind of recording resolution or discrete time interval limit, of the rocket’s entire motor burn phase, and at the same time process this accumulated acceleration with respect to time as a gradually increasing velocity. In the case of the V2 missile, when the correct predetermined velocity is reached, the velicity sufficient to achieve the desired range of the missile, the device trips the relays that close valves that shutdown the supply of steam to the turbo-pump, and thus shutdown the rocket motor itself.

The chart shows water delivery in litres per minute per injector

Each burner cup of the V2 rocket engine injector system has forty-four brass inserts, but each cup also has twenty-four 2mm diameter plain holes, 30 deg apart, drilled into the cup’s central wall. To mimic this for testing purposes, we created a brass insert that has a base with just a 2mm central hole. The base is sized to be consistent with the 4 to 5mm cup wall. V2RH image

V2 rocket engine fuel injector inserts – a part of our collection used for the water tests with various types shown. The tool shown is a pin-wrench used to fit the inserts into the test apparatus. V2RH collection image

3305D fuel injector insert showing swirl cone nebular, and 4 steady steams emanating from cooling pores.

3305D fuel njector insert showing comparison nebular and jet stream pattern with high and low pressure. Left image shows correct hollow cone-shaped aerosol effect from central 6mm orifice, that is also creating a fine mist around and within the cone, and 4 steady steams emanating from cooling pores. Right image shows the effect of reduced pressure: a dropping poorly formed cone, composed of larger slower moving droplets, and a tendency for the thicker spray to combine and cause ‘dribbeling’ with much fluid failing to clear the injector face.

3304D higher volume fuel injector insert (with three inlet apertures: 2 swirl, 1 jet) showing swirl cone nebular, steady central jet, and 4 steady steams emanating from cooling pores.

Standard fuel injector inserts for production series 18-pot injector head. Insert 1 (3304D/3305D) shows four thin wires demonstrating the angles of all four ‘cooling’ pores. Insert 2 (3305D/2131E) has two 1.3mm twist drill showing the edge bores for the gyroscopic swirl inlets. Insert 3 (3305D) shows another view of the cooling pore angle and origin. V2RH image

V2 Fuel Injector insert: part code 2131E from injector pot echelon A (nearest to LOX spray head). The push-together two part construction of the insert is shown here. The two parts were pushed together in a specially shaped tool set that compressed the thin skirt on the female part into a recess cut into the male part. The failure test for this component required that the mated parts resist a separating force of 300kg. The two part design was dictated by the small size of the 2mm exit orifice and the funnel shaped introduction to the exit orifice. In the case of the other three standard inserts, the large 6mm exit orifice allowed a sub 6mm milling cutter, with a thin support shaft and a top chamfer, to be used in such a way that the area below the exit orifice could be undercut to create an injector cavity with a diameter larger than the 6mm entry point.

Fuel injector inserts for production series 18-pot injector head showing general shape and thread position. For further details see associated image. The lowermost insert have been halved to reveal the cavity shape, orifice edge, inlet and cooling apertures. V2RH image

Single nozzle insert test rig used by V2 Rocket History to test spray shape and volume at supply pressures consistent with fuel pressures specified for the injector head of summer 1944. The test system features an adjustable pressure regulator and fluid pressure gauge. For test purposes the device was simply connected to a relatively high pressure mains water supply. And although water does not have the same viscosity of the 75% Ethenol to 25% water mix of the V2’s fuel it was considered close enough by the German technicians, who regularly used plain water as a substitute when testing issues related to furl flow rather than combustion. A 2131E fuel injector insert is shown installed in the holder at the front of the rig, but as the thread was the same on all inserts the nozzle can be changed for other models easily with aid of a pin spanner. See video for a demonstration of this simple test system.

Single nozzle insert test rig used by V2 Rocket History to test spray shape and volume at fluid supply pressures consistent with fuel pressures specified for the injector head of summer 1944. A 2131E fuel injector insert is installed in the holder at the front of the test rig, but as the thread was the same on all inserts the nozzle can be changed for other models easily with aid of a pin spanner. See video for a demonstration of this simple test system.

3305D injector insert showing larger low-velocity droplets and ‘dribbly’ performance due to insufficient pressure. The cone shaped aerosol is not functioning. Broken streams can be seem emanating from the four cooling pores.

3305D injector insert showing comparison nebular and jet stream pattern with high and low pressure. Top image shows correct hollow cone-shaped aerosol effect, from central 6mm orifice, that is also creating a fine mist around and within the cone, and steady steams emanating from cooling pores. Bottom image shows the effect of reduced pressure: a dropping poorly formed cone, composed of larger slower moving droplets, and a tendency for the thicker spray to combine and cause ‘dribbeling’ with much fluid failing to clear the injector face – unlike the image above, where the injector face is clear of drips.

Image shows a correctly formed nebular cone attended by a fine mist. the four injector cooling jets are well shown, and although fluid beading can be seen on the face of the injector, there is insufficient liquid to cause dripping.

Single fuel injector water test rig showing a 3305D bress insert about to be tightened home using a pin-wrench. V2RH image

3304D higher volume injector insert (with central jet) showing comparison nebular and jet stream pattern with high and low pressure. Top image shows correct hollow cone-shaped aerosol effect from central 6mm orifice, that is also creating a fine mist around and within the cone, and strong single central (non-swirl) jet can be seen as well as 4 steady steams emanating from cooling pores. Bottom image shows the effect of reduced pressure: a dropping poorly formed cone, composed of larger slower moving droplets, and a tendency for the thicker spray to combine and cause ‘dribbeling’ with much fluid failing to clear the injector face. The appearance of central jet however seem largely unchanged.