wuzak
Captain
The RAE received a Jumo 222 at the end of the war in order to examine its features. It was not complete, missing some of its pipework.
Referencing captured German documents they determined the engine to be a 222B-2 with right hand rotation.
The specs of the engine were as follows:
*the nominal volume with the 135mm stroke was 49.88l/344ci. The calculated volume takes into account the actual piston strokes, which varied because of the articulated rods.
The cylinders were numbered by the RAE in the following manner:
Cylinder bank #1 was the horizontal right bank when looking from front to rear.
Cylinder bank # 2 was the right upper bank.
Cylinder bank #3 was the left upper bank.
Cylinder bank #4 was the left horizontal bank
Cylinder bank #5 was the left lower bank.
Cylinder bank #6 was the right lower bank.
Cylinders were then numbered sequentially front to back for each of the banks.
Bank #1: 1, 2, 3, 4
Bank #2: 5, 6, 7, 8
Bank #3: 9, 10, 11, 12
Bank #4: 13, 14, 15, 16
Bank #5: 17, 18, 19, 20
Bank #6: 21, 22, 23, 24
Using this numbering system, he firing order was:
The cylinder in the upper row fired at the same time as the corresponding cylinder in the bottom row. ie 1 and 14 at the same time, 24 and 11, etc.
Traditionally radials have odd numbers of cylinders, so that it takes two rotations to fire all cylinders in a row, every second cylinder firing until this is completed.
This is not possible with an even number of cylinders per row. If you look closely at the way the firing order works, two cylinders fire, two are missed, then two fire, tow missed then two fire, this happening over 2 revolutions.
For the first row if the 222 the firing order is 5-1-13-9-21-17.
The cylinders had different strokes because of the articulated rods. The actual strokes were:
Bank #5 was the one with the master rods, bank #2 was opposite bank #5.
The crankshaft had 4 throws, the two end ones being 180° opposed the the centre ones. There were counterweights mounted on the end crank cheeks and one either side of the centre main bearing.
The crankcase was built in 2 halves. The upper half mounted 4 cylinder banks, the lower half 2 cylinder banks.
There were 5 main bearings. The centre main bearing was wider. The bearings were shell type with 0.5mm coating of silver-lead over a steel backing. The bearings were stopped from spinning with a dowel.
One part of the main bearing fitted directly into the upper crankcase and the other half was fitted to a bearing cap.
As the crankshaft was a single piece type, the master con-rod was split. The rod part had 2 holes for the articulated rods, the cap had 3. The mating surfaces were serrated for location.
I'll post some more tomorrow.
Referencing captured German documents they determined the engine to be a 222B-2 with right hand rotation.
The specs of the engine were as follows:
Code:
Bore: 140mm 5.51"
Stroke: 135mm 5.31"
Swept Volume: 2124cc 129.6ci (per cylinder)
Clearance Volume: 370cc 22.6ci
Capacity: 50.976l 3111ci*
Compression Ratio: 6.735:1
Supercharger
Impeller Diameter: 324.7mm 12.784"
MS/Low Ratio: 6.7:1
FS/high Ratio: 9.16:1
Propeller Reduction Gear
Type: Epicyclic
Ratio: 0.3667:1
Weight of Engine: 1246kg 2747lb*the nominal volume with the 135mm stroke was 49.88l/344ci. The calculated volume takes into account the actual piston strokes, which varied because of the articulated rods.
The cylinders were numbered by the RAE in the following manner:
Cylinder bank #1 was the horizontal right bank when looking from front to rear.
Cylinder bank # 2 was the right upper bank.
Cylinder bank #3 was the left upper bank.
Cylinder bank #4 was the left horizontal bank
Cylinder bank #5 was the left lower bank.
Cylinder bank #6 was the right lower bank.
Cylinders were then numbered sequentially front to back for each of the banks.
Bank #1: 1, 2, 3, 4
Bank #2: 5, 6, 7, 8
Bank #3: 9, 10, 11, 12
Bank #4: 13, 14, 15, 16
Bank #5: 17, 18, 19, 20
Bank #6: 21, 22, 23, 24
Using this numbering system, he firing order was:
Code:
1 24 7 2 22 8 4 21 6 3 23 5
14 11 20 13 9 19 15 10 17 16 12 18The cylinder in the upper row fired at the same time as the corresponding cylinder in the bottom row. ie 1 and 14 at the same time, 24 and 11, etc.
Traditionally radials have odd numbers of cylinders, so that it takes two rotations to fire all cylinders in a row, every second cylinder firing until this is completed.
This is not possible with an even number of cylinders per row. If you look closely at the way the firing order works, two cylinders fire, two are missed, then two fire, tow missed then two fire, this happening over 2 revolutions.
For the first row if the 222 the firing order is 5-1-13-9-21-17.
The cylinders had different strokes because of the articulated rods. The actual strokes were:
Code:
Bank #1: 1 2 3 4 136.9mm
Bank #2: 5 6 7 8 135.0mm
Bank #3: 9 10 11 12 136.9mm
Bank #4: 13 14 15 16 137.5mm
Bank #5: 17 18 19 20 135.0mm
Bank #6: 21 22 23 24 137.8mmBank #5 was the one with the master rods, bank #2 was opposite bank #5.
The crankshaft had 4 throws, the two end ones being 180° opposed the the centre ones. There were counterweights mounted on the end crank cheeks and one either side of the centre main bearing.
The crankcase was built in 2 halves. The upper half mounted 4 cylinder banks, the lower half 2 cylinder banks.
There were 5 main bearings. The centre main bearing was wider. The bearings were shell type with 0.5mm coating of silver-lead over a steel backing. The bearings were stopped from spinning with a dowel.
One part of the main bearing fitted directly into the upper crankcase and the other half was fitted to a bearing cap.
As the crankshaft was a single piece type, the master con-rod was split. The rod part had 2 holes for the articulated rods, the cap had 3. The mating surfaces were serrated for location.
I'll post some more tomorrow.
