List of WWII Maybach engines

This is an incomplete list of gasoline engines designed by Maybach AG, manufactured by Maybach and other firms under licence, and fitted in various German tanks and half-tracks before and during World War II. Until the mid 1930s, German military vehicle manufacturers could source their power plants from a variety of engine makers; by October 1935 the design and manufacture of almost all tank and half-track engines was concentrated in one company, Maybach AG, located in Friedrichshafen on Lake Constance.[1]

V-12 Maybach HL230 P30, developing 700 PS.[a]

The firm designed and made a wide range of 4, 6, and 12-cylinder engines from 2.5 to 23 litres; these powered the basic chassis designs for approximately ten tank types (including tank hunters and assault guns), six half-track artillery tractor designs, plus two series of derived armoured personnel carriers. Maybach also designed a number of gearboxes fitted to these vehicles, made under licence by other manufacturers. Friedrichshafen was also home to the Zahnradfabrik (ZF) factory which made gearboxes for Panzer III, IV, Panther and Tiger tanks. Both Maybach and ZF (and Dornier) were originally subsidiaries of Luftschiffbau Zeppelin GmbH, which also had a factory in the town.

Maybach used various combinations of factory letter codes (discussed below) which specified the particular ancillaries to be supplied with each engine variant: the same basic model could be fitted in a number of vehicles, according to the original manufacturer's design requirements. For example, the basic 3.8 and 4.2 litre straight-6 engines (the NL38 and HL42) fitted in various half-tracks could be supplied in at least 9 different configurations, although every single component was to be found in a single unified parts list.[2]

However, as the war progressed, a number of problems hampered the German armaments production effort. The factory's inability to manufacture enough complete engines as well as a huge range of spare parts, meant that there was often a lack of both. Conflicts between the civilian Reich Ministry of Armaments and Munitions and the German Army led to a failure to set up an adequate distribution system, and consequent severe shortages of serviceable combat vehicles. In April 1944 an Allied bombing raid put the Maybach factory out of action for several months, and destroyed the ZF gearbox factory.

Maybach history, 1935–1945Edit

In order to rationalise Germany's military vehicle production, sweeping changes were made to its entire automotive industry. Heinrich Ernst Kniepkamp [fr], head of the Heereswaffenamt (HWA), oversaw the re-organisation. By late October 1935, Maybach had been designated the sole designer of engines for the army, with production outsourced to other firms including Nordbau (Norddeutsche Motorenbau GmbH) in the south-eastern Berlin suburb of Niederschöneweide beside the River Spree.[1][3][4]

 
A Tiger tank undergoing an engine swap (HL230 P45), Romania 1944

Although a steady supply of spare parts is essential to an army in the field, the production of complete engines always took priority over providing spares.[b] Germany never achieved the industrial capacity needed to keep its military vehicles running efficiently: when the Russian campaign got underway, the deficiencies of the armaments industry and the organisation of maintenance depots became obvious.[5] The German armed forces suffered from continual shortages of spare parts for tanks and half-tracks until the end of the war.[6] When the first Tiger I tanks arrived in Russia in autumn 1942, there was only one spare engine and one transmission for every 10 tanks. A critical lack of spare parts meant that most of them were out of commission within a short period, sometimes for weeks on end.[7] Despite various attempts at re-organisation, friction between the distribution systems of the German Army (das Heer) and the civilian Ministry of Armaments (and from 1944 the 'Rüstungsstab') often led to confrontation and inefficiency.[8]

By late 1943 there was a severe shortage of spare tank engines.[c] Rather than concentrate on proven designs, Maybach continued to bring out new, relatively untested models; the wide variety of engine types seriously hampered efforts to fix the multiple defects which Maybach engines developed under combat conditions.[7] The extreme difficulty of stocking so many spares at the front, several thousand kilometres away from the factory, swiftly led to vehicles being unserviceable for combat. Because the armaments industry was already working at full capacity, it was not possible to completely replace obsolete models with new versions. Instead, the number of tank models and types within each series issued to the field forces increased steadily, which only made the maintenance and repair situation worse.[9]

Severely damaged tanks from the Russian front were initially shipped back to Germany, or to the Nibelungenwerk or the Vienna Arsenal for repair;[10][11][12] but the prospect of inevitable delays often meant that vehicles were instead cannibalised at the front for parts. Often when a new engine was delivered, there was little left except the hull of the tank it was intended for.[13] Nevertheless, the maintenance crews did their best, often retrieving knocked-out tanks under considerable difficulties.[d]

As the war progressed, new Maybach engines tended to be rushed into production, without adequate testing and development. As a result, they were viewed as unreliable.[15] All the 325 new Panther tanks delivered to Russia in early 1943 had to be returned because of serious defects in the steering;[16] they were underpowered by the HL210 P30 engine, and its replacement, the HL230 P30 (which didn't arrive until late 1943) suffered from over-heating, fires in the engine compartment and blown gaskets.[17]

By way of comparison, the Russian Army used a single basic engine (the V-12 diesel Kharkiv V-2) to power the majority of its tanks – with a few modifications – starting with the BT-7M and its successor the T-34,[18] producing 500 hp (370 kW) @ 1800 rpm in 1939;[19] the SU-85 and SU-100; the KV-1 and KV-2 (600 hp in 1939); and the IS-2, ISU-122 and ISU-152 and the T-10. Maybach didn't produce a more powerful acceptable engine until late 1943 with the HL230 P30.

Although the German Army used various combat vehicles appropriated from other countries, they continued to be powered by their original engines. Maybach engines were fitted to the German fighting vehicles for which they had been designed.

General designEdit

A number of Maybach motors shared the same basic design but had different engine sizes, the larger engines having bigger cylinders to increase the capacity. Similar engine designs had shared parts lists, e.g. the NL38 and HL42; the HL57 and HL62; and the HL108 and HL120.[20]

The 6-cylinder Maybach engines used a single Solex 40 JFF II down-draught carburetor,[21] and earlier V-12s used two.[22] Later V-12s used Solex 52 JFFs.

A hand-cranked inertia starter (Schwungkraftanlasser) was fitted to the V-12 engines to supplement the Bosch electric starter motor.[23]

NomenclatureEdit

IntroductionEdit

Maybach used a series of letter codes and numbers to identify specific engine models, namely:

  • NL / HL – performance
  • TU / TR – lubrication
  • K – clutch
  • R / RR – belt drives for compressor and fans
  • M – magneto ignition

Although these codes usually indicate what ancillary equipment was fitted at the factory (e.g. the HL42 TUKRRM and the HL57 TR), there are some exceptions, discussed below.

The individual engine number and its capacity, the model type, and year of manufacture are hand-stamped on each crankcase. On 6-cylinder models with magneto ignition, this information is found on the magneto housing: e.g.[24]

MOTOR Nr 730192
    4198 ccM.
   HL42 TUKRM
      1943

PerformanceEdit

  • NL = Normalleistung (normal performance motor)
  • HL = Hochleistung (high performance motor)

This is followed (without space) by the approximate engine capacity (e.g. HL42 = approx. 4.2 litres.)

LubricationEdit

  • TR = Trockensumpfschmierung (dry sump lubrication), generally fitted to tanks - because of low ground clearance, and to some half-tracks. There is no sump below the crankcase: the engine oil is contained in a tank on one side. On later V-12s there is a tunnel through the oil tank, through which the hand crank for the inertia starter passes, operated from the outside rear of the vehicle.[25]
In a number of cases, especially the dry sump tank engines (e.g the HL108 TR), this is the complete designation of an engine: in other words, there is no factory-fitted clutch (K) attached to the engine; no extra drive belts driving a compressor (R) and/or dual fans (RR) on custom pulleys; ignition is achieved via a distributor rather than a magneto (M); and no specific vehicular installation (P, S, or Z) is implied.[e]
  • TU = Tiefer Unterteil ('deep lower part' i.e. wet sump), only fitted to some half-tracks. The sump has an inverted triangle shape, bolted to the underneath of the crankcase housing.
Most of the TU (wet sump) type engines were installed in half-track artillery tractors Sd.Kfz 6, 7, 8, 9 and 11, and were fitted with some or all of the ancillaries (K, R, or M). There appear, nevertheless, to be exceptions. For example, the HL57 TU was apparently only installed in some versions of the Sd.Kfz. 7, which was in fact fitted with a factory clutch, compressor and magneto. But since it was the only model available in that engine size, the extra equipment was fitted as standard and the extra letter codes were not included in the model number.[f]

In addition, 'T' by itself has no meaning; it is always directly followed by either R or U, but 'R' in this position should not be confused with an (R) signifying a belt drive (see below). Furthermore, in some sources engines may be referred to simply as e.g. "a Maybach HL 120 of 300 metric horsepower",[citation needed] which indicates that further information is needed to identify the particular model number.

TransmissionEdit

  • K = Kupplung or Kupplungsgehäuse (clutch housing): a clutch is attached directly to the flywheel end of the crankshaft, driving a manual gearbox. This type of transmission was fitted to most half-tracks, both TR and TU types, and to early Panzer Is. The gearbox could also have a rear power take-off shaft fitted, to power a gun or crane turntable on half-tracks such as the Sd.Kfz. 9/1.[26]
 
Panzer III engine and Maybach-Variorex pre-selector gearbox (in German). Click picture for English translation.
  • If there is no factory-fitted clutch (K), this indicates a tank engine (except early Panzer Is). Instead, a horizontal cardan shaft connects the flywheel to a separate gearbox next to the driver. This could be a pneumatically-controlled, pre-selector Maybach-Variorex (e.g. certain Panzer IIIs and Stug III); or a synchromesh ZF Aphon (e.g. later Panzer III and IVs); or a hydraulically-controlled Maybach-Olvar (e.g. Tiger I and II).
    • A 10-speed Maybach-Variorex SRG 328 145 gearbox[g] was fitted in Panzer IIIs Ausf. E–G,[27] operated by vacuum pressure generated by a compressor (R) - see next section. The main clutch is integral to the gearbox housing.[28] (See also diagram on right.)
    • Other tank gearboxes included the synchromesh ZF Aphon SSG[h] 5x and 7x series gearboxes (the SSG 75 fitted in early Panzer IV had five forward gears and one reverse:[29] the 76 and 77 had six forward and one reverse). The main clutch (Hauptkupplung) (LA 120 HD) was bolted to the gearbox on the SSG 75, and incorporated into the main housing in the 77.[30] The SSG 77 gearbox replaced the mechanically vulnerable Variorex in the Stug. III Ausf. C.[31][32] Bigger tank engines (e.g. the HL230) used a Maybach-Olvar hydraulically-operated gearbox such as the Olvar EG 40 12 16 (8 forward gears, 4 reverse), fitted to Tiger Is and IIs.[33][34]
    • Some half-track gearboxes also included a power take-off shaft (PTO) driving an external winch (German: Seilwinde).[i]

CompressorEdit

  • R = Riemenantrieb für Luftpresser (belt drive for air compressor), driven by a pulley at the other end from the flywheel. The compressor is connected to various types of equipment, including:
    • Panzer III and Stug III (some variants) – Maybach Variorex SRG 328 145 pre-selector gearbox
    • Sd.Kfz. 10 and 250 – Variorex VG 102 128H pre-selector g/box
    • Sd.Kfz. 11 and 251 – air brakes on towed equipment (e.g. Pak 40 anti-tank gun)
    • Sd.Kfz. 6–9 – pneumatic foot/parking brake + towed equipment[35] (e.g. 15 cm sIG 33 towed by the Sd.Kfz 7[36])
On certain Panzer IIIs, and Stug III, and on the Sd.Kfz. 10 with its derivative the Sd.Kfz. 250, the compressor provided the (reverse) pressure for a pneumatically-operated pre-selector gearbox. To shift gears, the pre-selector lever is set in the desired position or slot, and then the clutch pedal is depressed and released. The air inlet of the compressor is connected to the system, not the outlet: the compressor works "in reverse" to create a vacuum. Inside the Variorex gearbox, there are vacuum-actuated pistons: these move dog clutches, which select the desired gearing.[28] On inline-6 engines, the compressor is mounted in various locations - either on the left or right at the front of the engine, or on top of the cam cover nearest the driver.
  • KR = Clutch and compressor: production versions of the Demag half-tracks, the Sd.Kfz. 10 (manufacturer type D7) and Sd.Kfz. 250 (D7p) were fitted with a Maybach SRG, type VG 102 128H,[j] with 7 forward and 3 reverse gears.[37][38][39] Although they worked on the same vacuum principle as the bigger tank pre-selector gearboxes, these types had no integral clutch, and were much smaller than those fitted to tanks. The drive passed through a standard clutch attached to the engine via a cardan shaft into the gearbox: depressing and releasing the clutch pedal simultaneously disengaged the main clutch and actuated the vacuum pistons to engage the pre-selected gear ratio.[40][41][42]
  • KRR = Clutch, compressor, and extra belt drives for radiator fans: fitted to a number of Sd.Kfz. 11 and 251 variants.[37] A triple V-belt pulley mounted at the top of the engine also drove the twin cooling fans mounted directly between the engine and the radiator.[43][k]

IgnitionEdit

  • M = Schnapper-Magnetzündung (impulse magneto ignition): some models had a Bosch 12-volt magneto for the ignition. On 6-cylinder engines, the magneto is geared to the starter ring on the flywheel.[21] On 12-cylinder engines the magnetos were located either on the camshaft ends, or between the cylinder heads, driven by a large internal helical-cut ring gear.[45]
  • The alternative to a magneto was an ignition coil (German: Zündspule) connected to a vertically-mounted distributor (German: Zündverteiler), often driven from one end of the camshaft.[46]
  • Most models were also fitted with a belt-driven dynamo for charging the batteries for the electric starter motor, lighting, etc. On 4- and 6-cylinder engines the dynamo was usually connected by a drive shaft to a separate coolant pump located close to the cylindrical oil cooler.

InstallationEdit

These letters were only used on some models, e.g. HL42 TRKM S, HL45 Z, HL230 P30. The HL230 P30 was designed to be fitted in the Panther, whose prototype was the 30-ton class VK30.02; the HL230 P45 went in the Tiger, whose final 45-ton class prototype was numbered VK45.01.[47]

ExamplesEdit

  • NL38 TRKM = Normal performance 3.8 litre, dry sump, clutch, magneto
  • HL62 TR = High performance 6.2 litre, dry sump, pre-selector gearbox (no K), no compressor (R), ignition coil & distributor (no M)
  • HL108 TUKRM = High performance 10.8 litre, wet sump, clutch, compressor, magneto

GalleryEdit

List of Maybach enginesEdit

List of Maybach WWII engines
Model Type Capacity (Litres)[p] Power (PS)[q] @rpm[r] Application
HL25 I-4 2.5 65 2,800 Pre-production Sd.Kfz. 10 D4[3]
HL30 I-4 3.0 95 3,000 Le.WS - Leichter Wehrmacht Schlepper (Light Army Tractor) (1st & 2nd models)[48][49]
NL38 TRKM[50] I-6 3.817[s] 90 3,000 Panzer I Ausf. B and derivatives, e.g. 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B:[51] Sd.Kfz. 10 D6 (pre-production):[52] early Sd.Kfz. 11[53]
NL38 TUK I-6 3.817 90 early Sd.Kfz. 6 (BN 1 8) [54][55]
HL38 TUKR I-6 3.817 100 2,800 Sd.Kfz. 11 (early versions)[56][t]
HL42 TRKM I-6 4.170[u] 110[53][v] Sd.Kfz. 10 type D7 (production models):[57][w]
HL42 TUKRR[58] I-6 4.198 100 Sd.Kfz. 11: Sd.Kfz. 251 (various models, incl. /16 & /21)[59]
HL42 TUKRM I-6 4.198 100 2,800 Sd.Kfz. 250: Sd.Kfz. 11,[60] Sd.Kfz. 251
HL42 TRKM-S[61] I-6 4.198[x] 100 3,000 Leichter Wehrmachtschlepper (Le.Ws) (late models) [48] Schwerer Wehrmachtschlepper (s.Ws)[62]
HL45 P I-6 4.678 105[y] Panzer I Ausf. C/F and Ausf. J[63]
HL45 Z I-6 4.678 105[y] 2,800 HKp 602/603 (prototype replacement for Sd.Kfz. 251)[64][65]
HL50 P I-6 4.995 110[z] 3,000 Kätzchen APC (prototype) · HKp 603/604 (later prototype replacement for Sd.Kfz. 251)[65]
HL52 TU[66] I-6 115[aa] Sd.Kfz. 7, 1st prod models[67]
HL54 TUKRM I-6 5.420 120?[ab] 2,600 Sd.Kfz. 6 (late models)[68]
HL57 TR I-6 5.698 130 2,600 Panzer II Ausf. a[69]
HL57 TU I-6 5.698 130 2,600 Sd.Kfz. 7, 2nd batch[70]
HL62 TR/TRM I-6 6.191 140 Panzer II Ausf. b–F:[71] Wespe[72]
HL62 TUK I-6 6.191 140 2,600 Sd.Kfz. 7, 3rd batch (KM m 10)[73]
HL64 I-6 6.4? 160 Sd.Kfz. 7 after 1943
HL66 P I-6 6.754 180? 2,800 Panzer II Ausf. G and L (Luchs)[74]
SHL66 I-6 6.754 Used in Pionierschnellboot[47][75][ac]
HL80[ad] I-6 8.0? 160? 2,600 Sd.Kfz. 7 (KM m 12 - 1939 projected design only)[70]
HL85 TUKRM V-12 8.505[76] 185 2,500 Sd.Kfz. 8[77]
HL90[ae] V-12 9.0[af] 360[ag] 3,000? Heuschrecke 10 - Grasshopper SPG[78]
HL98 TUK V-12 230 Sd.Kfz. 9 (FAMO F2 pre-production) [79]
HL108 TR V-12 10.838 250 Panzer III Ausf. A through D:[80] Panzer IV Ausf. A (only 35 made)[81]
HL108 TUKRM V-12 10.838 250 3,000 Sd.Kfz. 9 (production models)[82]
HL116 V-12
[ah]
11.048 250[83][ai] 3,300 Sturer Emil : HK1600 (prototype)[83]
HL120 TR V-12 11.867 300 2,000 Panzer III, Ausf. E:[27] StuG III Ausf. A:[31] Panzer IV Ausf. B, early C[27]
HL120 TRM112 V-12 11.867 300 Panzer III, Ausf. F-N:[84] StuG III: StuG IV: Hummel: Panzer IV Ausf. later C-J:[85] Elefant: Brummbär (Sturmpanzer IV)
HL157 P[aj] V-12 15.580 410? 3,000? VK 1602 Leopard (prototype)
HL174 V-12 17.4[ak] 450[86] 3,000 VK 3601 H (Henschel prototype)[86]
HL210 P30 V-12 21.353[87] 650 3,000? First 250 Panther Ausf. Ds (aluminium alloy cylinder block)[88][89]
HL210 TRM P45 V-12 21.353 650 3,000 first 250 Tiger Is (aluminium alloy cylinder block)[90]
HL224 V-12 22.4 680?[al] 3,000 VK 6501(H), (heavy tank prototype by Henschel based on Panzer IV)
HL230 P30[88][91] V-12 23.095[92] 700 Later Panther Ausf. Ds, all As and Gs[93] Jagdpanther, Tiger II (King Tiger),[94] : Jagdtiger : Sturmtiger : Panther II (prototype)[94]
HL230 P45 V-12 23.095 700 3,000 Later versions of the Tiger I and Sturmtiger (cast iron block)[90]
HL234[am] V-12 23.88 800 3,000 Panther II (proposed at later prototype stage, discontinued)[95]

Development of the HL210 and HL230Edit

 
Repairs on a Maybach HL210. Russia, June 1943, during Operation Citadel

A proposed replacement for the Panzer IV had been considered since around 1937. What became the Tiger tank went through a series of specifications, with the final revision (VK 4501) being made in May 1941.[96] Only a month later, the German armies invading Russia encountered the superior T-34 and KV-1: by December 1941 a specification for a 30-ton medium tank (which became the Panther) had been proposed as an immediate response to the Soviet tank threat.[97][an]

Development of the two tanks continued simultaneously: the Tiger prototype was demonstrated to Hitler on his birthday in April 1942,[101] and the first of two Panther prototypes was ready in August 1942.[97]

The weight of the Tiger had increased considerably since its inception, and although it was now considerably heavier than the Panther medium tank, Maybach proposed fitting almost exactly the same 21-litre V-12 650 hp engine in both tanks. To save weight, the cylinder block was cast in aluminium alloy, with cast iron liners. The pistons were made of low-expansion aluminium-silicon alloy with Si content of nearly 20%.[102] The engine for the original 30-ton Panther project was the Maybach HL210 P30,[88] while the 45-ton specification for the Tiger received the HL210 P45.[90] The only visible difference was the arrangement of the coolant ducts exiting the cylinder heads, since the Panther and Tiger had different flows through their radiators.[ao]

Quantity series production of the PzKpfw VI Tiger (Ausf. H) with the HL210 P45 engine began in August 1942,[101] and it is possible that production of the Panther's HL210 P30 was begun at much the same time. The first battalions to be equipped with the Tigers were the 502nd Heavy Panzer Battalion on the Eastern Front near Leningrad, and the 501st Heavy Panzer Battalion which was sent to Tunisia. Unfortunately, it swiftly became apparent that the Tiger was seriously underpowered, and the rush into production of the new engines meant that the inevitable design defects had not been ironed out. Nevertheless, when the new Tigers arrived in Russia, there was only one spare engine and one transmission for every 10 tanks. A critical lack of spare parts meant that most of them were out of commission within a short period.[16]

 
HL230 P30 in a Jagdtiger: note central magnetos and symmetrical rusty coolant connectors just above rear bulkhead.[ap]

The first PzKpfw V Panthers (Ausf. D) were similarly ill-fated; series production began in January 1943, but when they arrived in Russia in the spring the faults (including the steering and leaking engine gaskets) were so egregious that the entire batch had to be returned to Germany.[7] A special plant for rebuilding the Panthers was established near Berlin.[7]

In the meantime, Maybach re-designed the HL210, replacing the alloy cylinder block with a traditional cast-iron one. Although there was no space for a physically larger engine, the cylinders were capable of being bored out without compromising the engine's integrity. The new HL230 23-litre engines were installed from May 1943 in the latest production Panthers as the P30, and in Tigers as the P45.[103][104][aq]

Despite all the changes, the up-engined Panther Ausf. A with the HL230 P30 (which didn't arrive in Russia until late 1943) suffered from over-heating, fires in the engine compartment and blown head gaskets.[17]

Identifying HL210 and HL230 types
  • HL210: three air filters; magnetos are located separately at the end of each camshaft; on the oil cooler side the oil filter sits at a relatively upright angle, approx. 70°.
  • HL230: two air filters: magnetos are located centrally in a twin housing between the cylinder heads; oil filter sits at approx. 45°.
  • P30: the twin cast iron hot coolant ducts are symmetrical and visually similar, with separate feeds to l.h and r.h. radiators..
  • P45: the coolant ducts are siamesed into a single pipe leading to the r.h. radiator.[90]

Half-tracksEdit

German WWII half-track prime mover numbering may appear not to be strictly logical: the two smallest vehicles were introduced after most of the larger artillery tractors were in production.[105] In ascending order of engine size and therefore towing capacity, they were designed to tow the following:[106]

As Maybach designed new, more powerful engines, all these vehicle types received at least two and up to four different engine models during production of the latest batches. There remained the necessity of attempting to produce either spare parts or complete new engines, just to keep the older vehicles running.

See alsoEdit

ReferencesEdit

Notes
  1. ^ The HL230 P30 can be identified by twin central magneto housings between twin coolant ducts (white interiors), and the oil filter at approx. 45°.
  2. ^ (Müller-Hillebrand 1982, p. 21). The lead author of this pamphlet, General Burkhart Müller-Hillebrand [de] worked in the Operational History (German) Section [de] of the Historical Section of the US Army in Karlsruhe after the war, helping to write operational histories from the German point of view.
  3. ^ For example, an official report in September 1943 on the state of various battalions under the command of Panzerjäger-Regiment 656 (including the 653rd Heavy Panzerjäger Battalion) stated that sixty complete HL120 engines (two per tank) were needed to bring the Ferdinand battalions up to strength.(Munch 2005, pp. 62–3) In a long list of other modifications, only two related to the engine: the fuel line needed shielding from the exhaust; and oil leaked onto the fan housing, both leading to fires in the engine compartment.(Munch 2005, p. 64) A total of only 91 Ferdinands were ever built.
  4. ^ For example, up to five 18-ton Sd.Kfz. 9s were needed to haul an immobilised Ferdinand through the mire of the Eastern Front.[14]
  5. ^ Similarly, the HL57 TR and HL62 TR with no ancillaries were only fitted in the Panzer II.
  6. ^ Likewise, the bored-out HL62 TUK engines were also only fitted in the SdKfz 7; these also had a compressor (R), but this appears not to have been included in the model designation.
  7. ^ SRG = Schaltreglergetriebe, 'shift regulator [or controller] gearbox'. Maybach changed the name from SRG to Variorex in 1939. (Spielberger 1994, p. 37).
  8. ^ SSG =Schaltsynchronisiertegetriebe, 'shift synchronised gearbox'[citation needed]
  9. ^ Diagram of Sd.Kfz. 9 geartrain at Spielberger 1994, p. 215. Key, from r.: Seilwinde – winch; Untersetzergetriebe – reduction gearbox; Gleiskette – track; Bremszylinder – [air]brake cylinder; Lenkbremse – steering brake; Lenkgetriebe – steering gear; Kupplung – clutch; Luftfilter – air filter; Triebrad – driving wheel; Fahrbremse – road brakes; Triebradenantrieb – drivewheel gearbox; Wechselgetriebe – change speed gearbox.
  10. ^ VG = Variorex-Getriebe, 'Variorex gearbox'; H = Hohlachse, 'hollow axle'
  11. ^ "Cette motorisation est redésignée avec une lettre R supplémentaire (R = ventilation séparée), donnant ainsi les NL38 TUKRR, NL38 TUKRRM et HL42 TUKRRM."[44] This roughly translates as 'separate (or forced) ventilation', Fremdbelüftung.
  12. ^ Or perhaps Zondereinbau, special installation.
  13. ^ The serial number stamped on the magneto housing appears to be MOT 551253
  14. ^ Note the guide positioning and excessive tappet clearance of the far right inlet valve.
  15. ^ HL230. From top right: magneto housing, between hot coolant pipes (to radiator). Immediately below magnetos: fan drive housing (yellow interior) with locating hole for fan drive shaft (four bolts). Centre right: cast iron exhausts. Lower right: harmonic damper with splined centre. Far lower right, beneath yellow lifting eye: oil tank (partially hidden), with hole for inertia starter handle (hand crank).[25] Centre, below exhaust: dynamo (black). Lower centre: oil cooler, with cold water inlet (from radiator). Far lower left: oil filter (at 45°). Top centre: carburettor cover, with holes for twin air filters
  16. ^ Manufacturer's figures were given in litres. Exact engine capacities may vary slightly due to different values of π (Maybach used 355÷113), conversion into US customary units, rounding errors, etc. Details of engines fitted to a small number of prototypes are often vague. To work out engine capacity:
    Engine capacity in litres = (π/4 * bore2 (mm) * stroke (mm) * no. of cylinders) ÷ 1,000,000
    eg The Maybach HL85 has a bore and stroke of 95mm x 100mm. Taking π as 355÷113 (Maybach's own value),
    Engine capacity = (0.78539823 * 9,025 * 100 * 12) ÷ 1,000,000 = 8.505 litres.
  17. ^ Manufacturer's values for engine power were originally stated in PS (metric horsepower), which is approximately equivalent to imperial/US horsepower (1 hp = 1.04 PS, 0.7457 kW).
  18. ^ These are manufacturer's maximum rpm figures: under normal operating conditions, recommended revs were a couple of hundred rpm less - e.g. 2,600 rather than 2,800 rpm.
  19. ^ Frank (Frank 1990, p. 4) gives 3.790 litres. This value is incorrect: Frank appears to have taken π as 3.12, thus with bore x stroke = 90 * 100 mm: 3.12/4 = 0.78, * (8,100 * 100 * 6) / 1,000,000 = 3.790. Taking Maybach's value of π as 355÷113, and bore x stroke of 90 * 100 mm, the correct value is 3.817 litres.
  20. ^ A 100 hp Maybach engine was experimentally used in early Schnellbooten nos. S2–5 as an auxiliary power source which could operate the central propeller for silent running, but was found not to be needed. Source: Paterson, Lawrence (2015). Schnellboote: A Complete Operational History. Barnsley, Yorkshire: Seaforth Publishing. p. 24. ISBN 9781848320833.
  21. ^ (Frank 1990, p. 4). This value is incorrect. Frank appears to have taken π as 3.12, thus: 3.12/4 = 0.78, * (8,100 * 110 * 6) / 1,000,000 = 4.16988 = 4.170
  22. ^ Possibly an error for 100
  23. ^ The Sd.Kfz. 10 chassis had a hull like a tank, (unlike the other half-tracks which had a frame chassis), and therefore used a dry sump (TR) engine because of the engine bay's restricted height.
  24. ^ The figure 4.198 litres (taken from the manual) is arrived at by taking π as 355 ÷ 113, and bore * stroke = 90 x 110 mm (from the manual) : capacity = (0.78539823 * 8,100 * 110 * 6) / 1,000,000 = 4.198 litres.
  25. ^ a b Some sources claim 150 PS/hp, but 105 PS/hp seems more likely, given its place in the hierarchy.
  26. ^ Some sources put the figure as high as 150 or 180 PS, but these figures seem unlikely,
  27. ^ Adjusted estimate
  28. ^ Adjusted estimate
  29. ^ This may be a similar engine to one described as a "6-cylinder Maybach S5 of approx. 7 litres", used to power motor boats used in bridging and rafting operations. See US War Department Technical Manual TM-E 30-451: Handbook on German Military Forces (March 1945), Chapter 8, p. VIII-93. The power output of 80 hp seems to be a misprint for 180.
  30. ^ Prototypes only?
  31. ^ Only three prototype vehicles were ever constructed, 1942-3. Details are vague. Photos of engine at "Maybach Motoren: Maybach HL 90". Fahrzeuge der Wehrmacht (in German). Retrieved 12 May 2020.
  32. ^ Approx. capacity based on the model number
  33. ^ Various sources say it was 300 or 360 hp. Although with a smaller displacement than the HL 120, its rpm was much higher, resulting in an excellent power output. The HL 90 was later developed into the HL 100 and HL 101.
  34. ^ A number of websites claim an I-6, but this seems unlikely given its place in the table
  35. ^ Many websites give a figure of 300 or even 360 hp, but it seems more likely to be around 280 hp, given its place in the table.
  36. ^ This engine and the HL174 appear only to have been fitted in a few prototypes, and there seem to be few reliable sources about them.
  37. ^ Some sources claim 19.144 litres, but this figure should be around 17.4 litres according to the manufacturer's designation
  38. ^ Adjusted estimate
  39. ^ Fuel injection engine, due to be completed by August 1945
  40. ^ Although the T-34 and KV tanks were almost impervious to the German 37mm anti-tank guns and the guns of the Panzer III and IVs,[98] they were not the primary reason why the German offensive ground to a halt by the end of 1941. Both sides suffered huge losses of personnel and matériel. The Battle of Smolensk delayed the German push towards Moscow.[99] Despite staggering losses including the Battle of Bryansk, the Red Army (backed up by physical defences constructed by innumerable civilian forces, both women and men, and the implacable weather - the rasputitsa) kept the invading forces at bay for long enough to keep re-located tank production going over the winter.[100]
  41. ^ The HL210 P30 is externally almost identical to the HL210 P45, apart from the hot coolant ducts (to radiator) at the flywheel end. On the P30 they are visually similar mirror images, and each duct is separately piped to the radiators on either side. On the P45 they are of unequal appearance, and are linked over the top of the fan drive housing into a 'Y'-fitting: a single pipe feeds the top of the offside radiator, which is coupled at the bottom to the top of the nearside radiator. The lower outlet of this feeds the oil cooler and then the water pump at the flywheel end. Photos make this much clearer.[88][90]
  42. ^ The four large central grey fittings are ducts to improve air flow in the engine bay.
  43. ^ The different cooling duct arrangements were carried over to their respective vehicles, and both designs received central twin magnetos, a new placement of the oil filter, and twin air filters in place of the triple cyclone housings.
Citations
  1. ^ a b Frank 1990, p. 20.
  2. ^ "Maybach NL 38 und HL 42 Motor TUKRR TUKRM TRKM TUKRRM Ersatzteilliste". classicseller.com (in German). Retrieved 12 May 2020.
  3. ^ a b Milsom 1975, p. 88.
  4. ^ "'Nordbau': Norddeutsche Motorenbau GmbH Niederschöneweide". Fotowiesel (in German). Retrieved 29 November 2020.
  5. ^ Müller-Hillebrand 1982, pp. 2-4.
  6. ^ Müller-Hillebrand 1982, p. 4.
  7. ^ a b c d Müller-Hillebrand 1982, p. 25.
  8. ^ Müller-Hillebrand 1982, p. 21.
  9. ^ Müller-Hillebrand 1982, p. 3.
  10. ^ Müller-Hillebrand 1982, p. 28.
  11. ^ Munch 2005, p. 172, 187.
  12. ^ Ankerstjerne, Christian (9 April 2016). "Homeland Armor Maintenance". Panzerworld. Retrieved 16 May 2020.
  13. ^ Müller-Hillebrand 1982, pp. 19, 25.
  14. ^ Munch 2005, pp. 138-9.
  15. ^ Milsom 1975, p. 9.
  16. ^ a b Müller-Hillebrand 1982, pp. 24-25.
  17. ^ a b Jentz 1995, pp. 61–62.
  18. ^ Müller-Hillebrand 1982, p. 43.
  19. ^ Hughes & Mann 1999, p. 34.
  20. ^ Photos of various front covers at "Maybach HL 62 TUK 6-cylinder Vergasermotor Owner's Manual Brochure". classicseller.com. Retrieved 20 May 2018.
  21. ^ a b Photo (with Solex carburetter above, and fuel pump below l.) at "Maybach Sechszylindermotor HL 42". flickr. Retrieved 20 April 2018.
  22. ^ Photos of Solex 40 carbs (end of page) at "Panzer IV Ausf.G (früh)". Rommelkiste.de (in German). Retrieved 20 April 2018.
  23. ^ Illustration in Koch 2000, p. 27.
  24. ^ Maybach HL42 TUKRM engine number. Fahrzeuge der Wehrmacht (in German). Retrieved 21 May 2018. Photo hosted at Fahrzeuge der Wehrmacht.
  25. ^ a b Hand-cranking various tanks (Youtube)
  26. ^ See Lubrication chart and photos of the model build at FAMO - Schwerer Zugkraftwagen 18 t - SdKfz 9 - Crane and cargo version by Panzerserra, retrieved 10 December 2019.
  27. ^ a b c Koch 2000, p. 20.
  28. ^ a b Photos, diagrams (some in English) and explanations here: "О крайней упоротости Pz.III ausf.E-G. Почему Pz.III ausf.E-G упороты (Flaws in the Panzer III ausf. E-G)". Kedoki (in Russian). Retrieved 21 April 2018. (Russian website, but machine translation is not too bad these days).
  29. ^ Perrett 1999, p. 5.
  30. ^ Spielberger 1994, diagrams p.36; 40.
  31. ^ a b Anderson 2016, p. 25.
  32. ^ Spielberger 1994, p. 40.
  33. ^ Photos at "Tiger II Maybach Olvar EG 401216 B transmission unit". stalker6delta.tumblr.com. Retrieved 17 July 2019.
  34. ^ Diagrams and explanations here: Hamby, Alan. "Transmission & Steering". Tiger I Information Centre. Retrieved 11 May 2020.
  35. ^ Many detailed photos at Lebert, Ron. "Sd.Kfz. 6/2 with 37mm Flak 36: air brake details". Missing-Lynx. Retrieved 11 May 2020.
  36. ^ "15 cm sFH 18 German field howitzer". Panzerserra Bunker. 10 March 2017. Retrieved 12 May 2020.
  37. ^ a b "Comparative table of various types of German half-tracked vehicles". TM-E 30-451: Handbook on German Military Forces. (Online version hosted at LoneSentry.com). U.S. War Department. 1945. Retrieved 11 May 2020.CS1 maint: others (link)
  38. ^ Jentz 2008, p. 3.
  39. ^ Jentz 2009, pp. 8, 20.
  40. ^ Good cutaway diagram here: "Автострадные танки… по-немецки" [Avtostradnye tanki... po-nemetski]. Warspot.ru (in Russian). Retrieved 11 May 2020.
  41. ^ Milsom 1975, p. 10.
  42. ^ Photos at Schwabe, W. (30 December 2019). "Surviving SdKfz.10 D7 Demag Half-Tracks" (PDF). Retrieved 11 May 2020. and Schwabe, W. (15 January 2020). "Surviving SdKfz. 250 Half-Tracks" (PDF). Retrieved 11 May 2020. (search both for MM Park, La Wantzenau)
  43. ^ Ashley, Terry. "German WWII Maybach HL 42 TUKRM Engine". PMMS. Retrieved 11 May 2020.
  44. ^ Couderc, Nicolas (April–May 2010). "Les Sd.Kfz.251 Ausf. A, B, C et D". Véhicules Militaires Magazine (in French) (32): 18–19. Retrieved 11 May 2020.
  45. ^ Photo of damaged HL120 TRM: Koch 2000, p. 18
  46. ^ Photo at "Maybach NL-38". Fahrzeuge der Wehrmacht (in German). Retrieved 21 May 2018.
  47. ^ a b "Which vehicles used the Maybach SHL 66 petrol engine?". Axis History Forum. Retrieved 16 May 2020.
  48. ^ a b Milsom 1975, p. 94.
  49. ^ "Leichte Wehrmachtsschlepper Adler leWS". Achtung Panzer!. Retrieved 20 April 2018.
  50. ^ Photo at "Maybach Motoren". Fahrzeuge der Wehrmacht (in German). Retrieved 20 May 2018.
  51. ^ Perrett 1998, pp. 6,8.
  52. ^ Milsom 1975, pp. 10, 88.
  53. ^ a b Milsom 1975, p. 11.
  54. ^ Milsom 1975, pp. 11-12.
  55. ^ "m. Zgkw. 5t (Sd. Kfz. 6): Medium Semitrack Prime Mover". Catalog of Enemy Ordnance Materiel, Volume 1: German. pp. 52, 53. lonesentry.com. Retrieved 22 April 2018. [NB includes pages missing/redacted from archive.org's copy of CoEO (G) 1945.]
  56. ^ Milsom 1975, pp. 11, 90.
  57. ^ Milsom 1975, pp. 88-89.
  58. ^ Photo at "Mittlerer gepanzerter Mannschaftstransportwagen (Sd.Kfz. 251) Typ Hkl 6p". wh-verstand.de (in German). Retrieved 21 May 2018.
  59. ^ CoEO (G) 1945, p. 46•1 [pdf 28].
  60. ^ Milsom 1975, pp. 90-91.
  61. ^ Photos of 1943 manual: "Mittlere Zugkraftwagen 5t (Sd.Kfz. 6)". wh-versand.de (in German). Retrieved 20 April 2018. bore * stroke: 90 x 110 mm, 4.198 litres, compression ratio 1:6.6
  62. ^ Milsom 1975, p. 75.
  63. ^ Perrett 1998, pp. 6-7.
  64. ^ "HKp 602/603". Achtung Panzer!. Retrieved 20 April 2018.
  65. ^ a b "HKp 602 / 603, HKp 605 / 606". Vehicles of the Wehrmacht 1939-1945. Retrieved 16 August 2019.
  66. ^ Photo at Milsom 1975, p. 40
  67. ^ Milsom 1975, p. 92.
  68. ^ Milsom 1975, pp. 12, 90.
  69. ^ Perrett 1998, p. 9.
  70. ^ a b Milsom 1975, pp. 12, 92.
  71. ^ Perrett 1998, p. 9; plate D.
  72. ^ Perrett 1998, p. 14.
  73. ^ Milsom 1975, p. 12.
  74. ^ Perrett 1998, p. 12.
  75. ^ Photo at Kuhn 2017, p. 16
  76. ^ Bore * stroke = 95mm x 100mm: see Sd.Kfz. 8 manual
  77. ^ Milsom 1975, pp. 13, 92.
  78. ^ "Heuschrecke 10". The Encyclopedia of Weapons of World War II. 1, p. 540. Sterling Publishing Company. ISBN 1-58663-762-2.
  79. ^ Milsom 1975, p. 13.
  80. ^ Perrett 1980, p. 5.
  81. ^ Perrett 1999, pp. 5-6.
  82. ^ Milsom 1975, p. 14.
  83. ^ a b Milsom 1975, p. 62.
  84. ^ Perrett 1980, pp. 6-9.
  85. ^ Perrett 1999, p. 6.
  86. ^ a b "King Tiger development". Swiss Military Museum Full. Retrieved 20 April 2018.
  87. ^ Bore * stroke 125 mm x 145 mm. Taking Maybach's value of π as 355÷113, engine capacity = (0.78539823 * 15,625 * 145 * 12) ÷ 1,000,000 = 21.353 litres.
  88. ^ a b c d Tech. info and labelled diagrams at Eberl, E. (3 February 2015). "Motor & Transmission". Panther 1944 (in German and English). Retrieved 14 February 2020.
  89. ^ The intended HL230 P30 was not ready. (Doyle & Jentz 1997, pp. 5–6).
  90. ^ a b c d e "The Maybach Engine". The Tiger I Information Center. Retrieved 8 January 2019.
  91. ^ Informative labelled photos from Musée des Blindés, Saumur, at "The engine (HL230 P30)". Tiger1.info. Archived from the original on 4 November 2007. Retrieved 14 February 2020.
  92. ^ Bore and stroke, 130 mm * 145 mm (5.1 in * 5.7 in) "German Armor Engines". PanzerWorld. Retrieved 21 May 2018.
    Taking Maybach's value of π as 355÷113, engine capacity = (0.78539823 * 16,900 * 145 * 12) ÷ 1,000,000 = 23.095 litres.
  93. ^ Doyle & Jentz 1997, pp. 6, 7, 8.
  94. ^ a b Jentz & Doyle 1993, p. 12.
  95. ^ Doyle & Jentz 1997, p. 10.
  96. ^ Perrett 1981, pp. 3-4.
  97. ^ a b Doyle & Jentz 1997, p. 4.
  98. ^ Zaloga 1994, pp. 14-15.
  99. ^ Bellamy 2007, p. 240.
  100. ^ Zaloga 1994, pp. 14-17, 18-21.
  101. ^ a b Perrett 1981, p. 4.
  102. ^ Saeed et al. 2013, p. 640.
  103. ^ Eberl, E. "The production periods of the Panther versions and the technical changes over the production periods". Panther 1944. Retrieved 16 May 2020. NB Engine changes half-way down in light grey.
  104. ^ Jentz & Doyle 2002, p. 14.
  105. ^ Milsom 1975, pp. 7-8.
  106. ^ Milsom 1975, pp. 6-7.

BibliographyEdit

External linksEdit