Tirpitz and Graf Zeppelin 1941

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delcyros
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Re: Tirpitz and Graf Zeppelin 1941

Post by delcyros »

The Landing gear of the Bf-109T is strengthened to cope with harder landing, I don´t think it´s an issue. Indeed a case can be made that the Bf-109T is more able to operate from carriers than was the Sea-Hurricane and Seafire, both of which received only limited changes for carrier operation, which amounted for some severe weight increases. In addition to these existential changes to the airframe, Bf-109T improved also the lift aspect (larger wingarea, more flap size) to counter the weight increases (the principal reason why it´s slower than the E4/N and E7/N) and offered more controll over the glide angle in powered approach due to the "Auftriebszerstörer" / air brakes.
The Fulmar I never operated with 87 octane fuel in combat and the manual states:
"Operational units 100 octane, other units 87 octane or higher". Both engines were combat approved for full boost (9/12 lbs) at any altitude and 3000rpm and the manual states:
That´s correct for mid 1942, the period the flight manual was referring to after it´s final revision in april 1942 but You can´t use that for earlier dates without other sources to back up such a claim.
Regarding cruising speed, the speeds given for the Fulmar in the manual are in IAS but those for the Fi-167 are probably TAS at its most favourable altitude. At 15000ft, the IAS cruise for a Fulmar is 130 knots = ~169 knots TAS. The Fi-167 speeds are also given at optimum altitude, and with a bomb load it's speed and climb rate will fall further.
Cruise speed referenced to for the Fi-167 is at "Bodennähe" and thus below and not at crit altitude. In "Bodennähe" IAS and TAS are identic. 15,000ft is way beyond the FULMAR´s crit altitude, which is 6,600 ft/9000ft, dependign on boost. There is little difference between IAS and TAS at such low altitude, altough it can be more dramatic in higher altitudes. You can take the point about dropping loads similarely to the Fulmar as well.
As mentioned previously, while I see that the Fulmar has advantages it´s not a one way situation dogfighting the nimble Fieseler because the FULMAR´s main assets are 8 x 0.3cal, dive and top end speed only. The Ju-87 is not a tougher opponent (it´s slower on the deck with 160kts and slightly faster with 189kts at 16,405ft). It´s very maneuverable but not as extreme in the low speed realm and neither the acceleration nor the climb is as good as the FULMAR or Fieseler. The FULMAR has more options dogfighting a Ju-87 than a Fieseler. Against the Bf-109T, I am still searching for a single aspect where the FULMAR is competetive.
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

delcyros wrote:The Landing gear of the Bf-109T is strengthened to cope with harder landing, I don´t think it´s an issue. Indeed a case can be made that the Bf-109T is more able to operate from carriers than was the Sea-Hurricane and Seafire, both of which received only limited changes for carrier operation, which amounted for some severe weight increases. In addition to these existential changes to the airframe, Bf-109T improved also the lift aspect (larger wingarea, more flap size) to counter the weight increases (the principal reason why it´s slower than the E4/N and E7/N) and offered more controll over the glide angle in powered approach due to the "Auftriebszerstörer" / air brakes.
The Fulmar I never operated with 87 octane fuel in combat and the manual states:
"Operational units 100 octane, other units 87 octane or higher". Both engines were combat approved for full boost (9/12 lbs) at any altitude and 3000rpm and the manual states:
That´s correct for mid 1942, the period the flight manual was referring to after it´s final revision in april 1942 but You can´t use that for earlier dates without other sources to back up such a claim.
Regarding cruising speed, the speeds given for the Fulmar in the manual are in IAS but those for the Fi-167 are probably TAS at its most favourable altitude. At 15000ft, the IAS cruise for a Fulmar is 130 knots = ~169 knots TAS. The Fi-167 speeds are also given at optimum altitude, and with a bomb load it's speed and climb rate will fall further.
Cruise speed referenced to for the Fi-167 is at "Bodennähe" and thus below and not at crit altitude. In "Bodennähe" IAS and TAS are identic. 15,000ft is way beyond the FULMAR´s crit altitude, which is 6,600 ft/9000ft, dependign on boost. There is little difference between IAS and TAS at such low altitude, altough it can be more dramatic in higher altitudes. You can take the point about dropping loads similarely to the Fulmar as well.
As mentioned previously, while I see that the Fulmar has advantages it´s not a one way situation dogfighting the nimble Fieseler because the FULMAR´s main assets are 8 x 0.3cal, dive and top end speed only. The Ju-87 is not a tougher opponent (it´s slower on the deck with 160kts and slightly faster with 189kts at 16,405ft). It´s very maneuverable but not as extreme in the low speed realm and neither the acceleration nor the climb is as good as the FULMAR or Fieseler. The FULMAR has more options dogfighting a Ju-87 than a Fieseler. Against the Bf-109T, I am still searching for a single aspect where the FULMAR is competetive.
The S Hurricane already had an extremely rugged LG and could operate up to ~8500lb MTOW in the SH IIC and both varients operated successfully on CVEs in arctic conditions. The Seafire is probably a better analogy, but the Seafire did have problems with LG failure under less than optimum conditions, and the outward folding LG design of the Seafire/109T is not optimal for CV operations, but we can only speculate on the 109T as it was never operated from a CV. The 109T LG was strengthed but it was also a heavier aircraft.

The Merlin VIII was cleared for 100 octane use by the time the Fulmar entered operational service and by Jan 1941 all RN CVs had to use 100 octane for the Fulmar II/Merlin XXX anyways.

The only time IAS and TAS are identical is at SL.

If you have the manual for the Fulmar, you will also see the cruise fuel consumption stated for 15000ft. My point is altitude is critical piece of the puzzle for cruise speeds and we don't have all the needed data for the Fi-167. The Fulmar cruised at ~100 knots less than maximum speed and max endurance was at 105 knots ( both speeds are well matched to the Albacore cruise speeds. How will a 109T cruise when escorting a strike? ), and yet we are told the Fi-167 cruises at only ~35 knots less than maximum? Maximum speed of an Albacore with Taurus XII/torpedo is ~145 knots at ~4500ft at MTOW, but max Cruise is 100 knots IAS up to ~15000ft. Maximum speed is dependent on critical altitude, but not max cruise which can be at considerably higher altitude as the engine can maintain supercharger pressure for cruise at much higher altitudes than for maximum power.

Against the 109T the Fulmar has better visibility due to the observer, better navigational capability, longer range and endurance. The Fulmar can also use a combat flap setting to decrease its turning circle and a Fulmar pilot reported being able to out-turn a Cr-42 this way.
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Re: Tirpitz and Graf Zeppelin 1941

Post by srgt rock »

German AW radar Freya developed in 1938. FuMG 39 units were being delivered in 1940.

For air search The German had the Fi 167 which could out perform even the Swordfish in slow speed handling. As stated, minimal CAP with additional fighters on deck ready to launch.

As Battle Group commander, I would understand the possibility of landing accidents but it would not stop me. The term acceptable losses applies. There would only need to be a larger number of fighters airborne AFTER BEING LOCATED. A smaller CAP need only deal with recon aircraft that are trying to shadow.

The British Cruisers in home waters Nov 41:
CL Cairo
CA Hawkins
CA Berwick
CA Cumberland
CA Norfolk
CA Exeter
CL Sheffield
CL Edinburgh

CV Argus would have replaced Ark Royal as she did historically. Argus would embark Ark Royal's air group but limited to her 20 plane capacity.

The Northern Battle Group in rapidly approaching the Iceland-Faroes Gap. The German admiral has a good idea about the British patrol ships. Fi 167s have been launched to determine the exact positions of the patrol ships in the sector that the Group will pass through. Ju 87s are prepared to fuel & arm.

How would the British Admiralty deploy its available ships and where?
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

srgt rock wrote:

How would the British Admiralty deploy its available ships and where?

RN dispositions were predicated on the KM not having any CVs, so having GZ pop into existence with historical RN dispositions is problematic. The RN would watched the completion and noted the flying trials and began making plans much sooner.


The RN had 2 carriers refitting on the US east coast ( Illustrious, Formidable) and Indomitable working up in Bermuda. All of these carriers were ready for sea by Oct 1941 and could have been given higher priority for earlier completion. Ark Royal, for example, would probably have been pulled out of Force H to reinforce the Home Fleet and Furious sent there in her place and/or HMS Eagle, which had been deployed to the South Atlantic in September.
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Dave Saxton
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Re: Tirpitz and Graf Zeppelin 1941

Post by Dave Saxton »

I would like to see some details on KM AW radar, since there is no evidence such radar was in existence in Dec 1941.
srgt rock wrote:German AW radar Freya developed in 1938. FuMG 39 units were being delivered in 1940.
Freya went into production in 1938. There were about 20 sets in operation when the war started. In April 1940 production of FuMG39 models ceased and were superseded by FuMG40 models. However, Freya wasn't mounted to warships. It wasn't necessary as the multi role Seetakt could also perform that role.

Land based Freya had already proved itself by Dec 1939 by warning of Bomber Command raids on German harbors. It was used successfully to direct BF109 day fighters to intercept causing unacceptable loss rates. This was a primary reason that Bomber Command gave up on daylight bombing.


Hohentwiel was one of the best ASV radars of WWII. It could have been made available to the KM Air Arm in 1941 if there was a need.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

Dave Saxton wrote:
I would like to see some details on KM AW radar, since there is no evidence such radar was in existence in Dec 1941.
srgt rock wrote:German AW radar Freya developed in 1938. FuMG 39 units were being delivered in 1940.
Freya went into production in 1938. There were about 20 sets in operation when the war started. In April 1940 production of FuMG39 models ceased and were superseded by FuMG40 models. However, Freya wasn't mounted to warships. It wasn't necessary as the multi role Seetakt could also perform that role.

Land based Freya had already proved itself by Dec 1939 by warning of Bomber Command raids on German harbors. It was used successfully to direct BF109 day fighters to intercept causing unacceptable loss rates. This was a primary reason that Bomber Command gave up on daylight bombing.


Hohentwiel was one of the best ASV radars of WWII. It could have been made available to the KM Air Arm in 1941 if there was a need.
Can you give me an example of Seetakt being used as an operational AW radar?

The Luftwaffe didn't have operational ASV in 1941 and Luftwaffe ASV was fitted to much larger aircraft and then not in any numbers until much later, 1943.

I know the KM and Germany had the technological base to build ASV but the fact is that they trailed the RN in deploying it by several years.
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Re: Tirpitz and Graf Zeppelin 1941

Post by Dave Saxton »

The Scheer used its Seetakt to detect and track aircraft. The Tirpitz also detected and tracked aircraft with Seetakt radar. The coastal Seetakts routinely detected and tracked aircraft. In 1944 tests a coastal Seetakt detected and tracked aircraft to ranges exceeding 240km. There's really no reason that if Freya could be a good AW radar (and it unquestionably was) that Seetakt could not be as well. They were sister radars based on the same basic design.

Hohentwiel was a very compact and light weight radar design. It was not limited to large aircraft. The main reason for the possible late deployment (If this is actually the case?) of Hohentwiel in large, long range, shore based, aircraft was the Luftwaffe's historical priorities and circumstances. The Luftwaffe controlled all German aviation during WWII historically. But if we are talking about KM aircraft carriers, then it has to be a very different set of priorities and circumstances than the historical. In that case, there's no reason that Hohentwiel could not have been deployed in numbers on carrier aircraft in 1941. There are reports of some LW Hohentwiel deployment in 41 historically, anyway.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

Dave Saxton wrote:The Scheer used its Seetakt to detect and track aircraft.

Hohentwiel was a very compact and light weight radar design.
Hohentwiel (Fug 200) was based on captured UK ASV II technology and the first prototypes were not operational until the end of 1941, and it was not widely used until 1943. Experimental use of Seetakt to detect and track aircraft is not the same as operational deployment of a usable AW radar.

The Luftwaffe was still the operating organization for GZ's air complement, rather like the interwar FAA which had RAF aircrew.
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Re: Tirpitz and Graf Zeppelin 1941

Post by Thorsten Wahl »

Development of Hohentwiel started in 1938 at the C. Lorenz AG in Berlin. The device was originally planned as ground-based fire control radar for the Luftwaffe. As Telefunken with its "Würzburg" device won the tender, the development of Hohentwiel stopped in 1939. In 1941 development was restarted as air based search radar with different antenna set.
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Re: Tirpitz and Graf Zeppelin 1941

Post by srgt rock »

Radar development in Germany in the late 30s was a KM initiative. Historically, the only radars the Germans had during the battle of Britain were the KM radars.

For our debate, GZ has a combination of Seetakt for longer range detection and FuMG 40 for more accurate altitude and bearing information. Further more, since the plan was to throw everything into this operation, grant the Northern Battle Group a limited number of ASV sets (2 to 4?) mounted on the Fi 167.

As Operation Rapier would be the worst nightmare the Admiralty could imagine, it is far to add Indomitable (still working up) to the British force availability table. Changing Eagle for Argus in Force H adds little change to the potential so I suggest leaving Eagle in the South Atlantic at this time.

Illustrious did not complete repairs until May 42. Formidable did not complete repairs until Dec 41. Formidable can become available off the east coast of the USA in December but what air group could she have embarked?

So, the Northern Battle Group op plan for breakout is to keep the fighters close for CAP duties, search with the Fi 167s and to limit air strikes to patrol ships. The intention is to punch a hole the surface search line and then use air recon to avoid British surface strike groups.

A side question. Has Admiralty already stopped the convoys in order to concentrate all available warships?
Last edited by srgt rock on Thu Dec 08, 2011 2:53 pm, edited 3 times in total.
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Re: Tirpitz and Graf Zeppelin 1941

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Development of Hohentwiel started in 1938 at the C. Lorenz AG in Berlin. The device was originally planned as ground-based fire control radar for the Luftwaffe. As Telefunken with its "Würzburg" device won the tender, the development of Hohentwiel stopped in 1939. In 1941 development was restarted as air based search radar with different antenna set.
Yes, Hohentwiel was a totally original design.

Seetakt could be and was used for operational AW from the beginning and throughout the war, both at sea and on land. This was not experimental use. And Freya was essentially Seetakt converted to operation on a longer wave length. Seetakt came first, then Freya. However, the Germans rejected the use of metric wave lengths at sea.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

Dave Saxton wrote:
Development of Hohentwiel started in 1938 at the C. Lorenz AG in Berlin. The device was originally planned as ground-based fire control radar for the Luftwaffe. As Telefunken with its "Würzburg" device won the tender, the development of Hohentwiel stopped in 1939. In 1941 development was restarted as air based search radar with different antenna set.
Yes, Hohentwiel was a totally original design.

Seetakt could be and was used for operational AW from the beginning and throughout the war, both at sea and on land. This was not experimental use. And Freya was essentially Seetakt converted to operation on a longer wave length. Seetakt came first, then Freya. However, the Germans rejected the use of metric wave lengths at sea.

Can you provide some specific dates and circumstances where Seetakt was used as an AW radar at sea?

When were the first 1/2 dozen Luftwaffe ASV radars used operationally?
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

srgt rock wrote:

Illustrious did not complete repairs until May 42. Formidable did not complete repairs until Dec 41. Formidable can become available off the east coast of the USA in December but what air group could she have embarked?
Ilustrious:

October: Post refit trials.

November 28th Passage to Jamaica to embark 12 SWORDFISH aircraft and carry out flying trials.

Formidable:

July to (Under repair
Preparations for installation of additional radars carried out.)
November (See RADAR AT SEA).

December Post refit trials.

Both ships were ready for sea in October, but their completion was delayed to fit new radar equipment, but this could certainly have postponed. Indomitable had already sailed to Bermuda in October.
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Re: Tirpitz and Graf Zeppelin 1941

Post by paulcadogan »

dunmunro wrote:The RN had 2 carriers refitting on the US east coast ( Illustrious, Formidable) and Indomitable working up in Bermuda.
Just for the sake of accuracy, Indomitable was working up in the Caribbean - she ran aground outside Kingston Harbour here in Jamaica on November 3rd. Were the Swordfish Illustrious embarked in Jamaica from Indomitable?
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Re: Tirpitz and Graf Zeppelin 1941

Post by dunmunro »

paulcadogan wrote:
dunmunro wrote:The RN had 2 carriers refitting on the US east coast ( Illustrious, Formidable) and Indomitable working up in Bermuda.
Just for the sake of accuracy, Indomitable was working up in the Caribbean - she ran aground outside Kingston Harbour here in Jamaica on November 3rd. Were the Swordfish Illustrious embarked in Jamaica from Indomitable?
Bermuda...Jamaica...hey it was somewhere warm and sunny... :D It's possible that Illustrious got some of Indomitable's Swordfish but Indomitable sailed for the far east with an outfit of Albacores and according to McCart, Indomitable had already embarked a squadron each of Albacores, Fulmars and Sea Hurricanes by Oct 13 1941, and conducted some offensive patrols en-route to Jamaica. First flying trials were conducted Oct 1 in UK waters with a squadron of 9 Albacores and he doesn't mention Swordfish being present on Indomitable.

Illustrious and Formidable both sailed for the UK from Norfolk Va, on Dec 12 19141, where they promptly ran into severe weather and collided on the 16th, necessitating further repairs.

However, at the very least, the RN would have kept Indomitable in the UK to work up, if there was even a hint of the KM having an operational CV.
Last edited by dunmunro on Thu Dec 08, 2011 9:21 pm, edited 1 time in total.
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