Archives: Gmedia Albums

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.

Brass liquid oxygen (LOX) spray nozzle.Note: the thread is shown in simplified graphic form. 3D model by Alexander Savochkin

Brass liquid oxygen (LOX) spray nozzle. Note: the thread is shown in simplified form. 3D model by Alexander Savochkin

One of the 18 liquid propellant (LOX and fuel) diffuser cups, showing three rows or echelons (A,D,& E) of brass injector inserts as well as two rows of drilled fuel feed holes. The LOX spray head is shown in the centre. 3D model by Alexander Savochkin

Cutaway showing echelon A with 2-part 2131E fuel injector inserts at the top of a propellant diffuser cup. Note the close proximity of the injector inserts to the simple ‘watering can’ type LOX spray head. One row of drilled fuel feed holes can be seen below the inserts. 3D model by Alexander Savochkin

This images shows a cutaway of a burner cup from outer Ring I of the injector head and shows injector insert eschelon D, & E as well as one row of drilled feed holes. Three fuel injector insert types can be seen: Top D, = 3303D (white), lower E, = 3304D (red), and E, = 3305D (blue). 3D model by Alexander Savochkin

This images shows a burner cup from outer Ring I of the injector head and the cutaway shows injector insert eschelon A,D, & E as well as two rows of drilled feed holes. Four fuel injector insert types can be seen: Top, A = 2131E, lower D, = 3303D (white), lowest E, = 3304D (red), and E, = 3305D (blue). 3D model by Alexander Savochkin

General view of the propellant diffuser cup inner core. The swirl caps of fuel injector inserts in positions A,D,& E can be seen clearly on the outside of the core as well as the central holes in the 3304D (red) inserts.The two rows of drilled fuel feed holes are also well shown. 3D model by Alexander Savochkin

Close-up detail showing independent pathway for fuel passing into injector head and fuel passed down from the head to be used for veil cooling system. Fig. A shows vertical passages for overall fuel feed to the head and Fig.B shows horizontal pathway for veil coolant fed from the head via the veil coolant distributor ring or manifold. 3D model by Alexander Savochkin

Underside view of injector head showing liquid propellant (LOX and fuel) diffuser cups, (see other images for insert and position nomenclature). Of note in this image are the pointing angles of the cups, positioned on a parabolic section to focus the propellant nebular stream into the central axis of the combustion space. Also of note are the large areas between each cup NOT employed in the injection process – initiating ‘clumpy’ and uneven propellant mixing initially below the injector face but also carried forward into the combustion space. The LOX spray head is shown in the centre of each cup. 3D model by Alexander Savochkin

Inverted view of injector head showing liquid propellant (LOX and fuel) diffuser cups, (see other images for insert and position nomenclature). Of note in this image are the pointing angles of the cups, positioned on a parabolic section to focus the propellant nebular stream into the central axis of the combustion space. Also of note are the large areas between each cup NOT employed in the injection process leading to structured propellant mixing as opposed to even homogeneous mixing. The four veil cooling inlet connectors are well shown. 3D model by Alexander Savochkin

View of injector head showing 18 liquid propellant (LOX and fuel) diffuser cups and head fuel valve seating ring at centre, (see other images for insert and position nomenclature). Visible immediately below the valve seat are the large connecting holes that allow fuel to flow from the inlet manifold and cooling jacket to the injector space (some brass injector inserts can be seen through the holes) after the head fuel valve is released to be opened by the turbo-pump supply pressure. The four veil cooling inlet connectors are well shown as are two of the outlet connection holes immediately above them. 3D model by Alexander Savochkin

View of the top of the injector head, with outer cups and pressed steel capping piece removed, showing, propellant diffuser inner cores with injector inserts and LOX supply pipe connection thread. The LOX spray head can be seen inside the LOX pipe connector. The swirl caps of fuel injector inserts in positions A,D,& E can be seen clearly on the outside of the cores and the two rows of drilled fuel feed holes are also well shown. 3D model by Alexander Savochkin

Another view of injector head showing liquid propellant (LOX and fuel) diffuser cups and head fuel valve seating ring at centre, (see other images for insert and position nomenclature). Visible immediately below the valve seat are the large connecting holes that allow fuel to flow from the inlet manifold and cooling jacket to the injector space (some brass injector inserts can be seen through the holes) after the head fuel valve is released to be opened by the turbo-pump supply pressure. The four veil cooling inlet connectors are well shown as are two of the outlet connection holes immediately above them. 3D model by Alexander Savochkin

A close-up view of the head fuel valve mounting flange (showing 12 fastener holes). Visible immediately below the top flange are the large connecting holes that allow fuel to flow from the inlet manifold and cooling jacket to the injector space (some brass injector inserts can be seen through the holes) after the head fuel valve is released to be opened by the turbo-pump supply pressure.

Exploded view showing some of the 1100 parts required for the complicated 18-pot injector head of the V2 25-ton thrust rocket engine. 3D model by Alexander Savochkin

Here the 18-pot head model has been cutaway to show the fuel cooling and fuel delivery spaces. the cooling jacket layer can be seen in the lowermost area of the head – below the centrally positioned fuel valve seat, between each cup at the lowest point, and ruining down toward the first set of veil cooling pores and the topmost coolant distributor ring. Note that the veil cooling system does not communicate with the regenerative cooling jacket and has its own feed pipes drawing fuel from the head injector space and not the cooling space. Visible immediately above the valve seat are the large connecting holes that allow fuel to flow from the inlet manifold and cooling jacket to the injector space after the head fuel valve is released to be opened by the turbo-pump supply pressure. 3D model by Alexander Savochkin

Liquid propellent (LOX and fuel) diffuser cup, showing three rings or echelons (A,D,& E) of brass injector inserts as well as two rows of drilled fuel feed holes. The LOX spray head is shown in the centre. Note the simple ‘shower head or watering can’ design of the LOX diffuser. A sealing washer can be seen fitted between the LOX diffuser and the steel cup. 3D model by Alexander Savochkin