Matrix Games Forums

Forums  Register  Login  Photo Gallery  Member List  Search  Calendars  FAQ 

My Profile  Inbox  Address Book  My Subscription  My Forums  Log Out

An error in IJN CV capacities?

 
View related threads: (in this forum | in all forums)

Logged in as: Guest
Users viewing this topic: none
  Printable Version
All Forums >> [New Releases from Matrix Games] >> War in the Pacific: Admiral's Edition >> An error in IJN CV capacities? Page: [1] 2   next >   >>
Login
Message << Older Topic   Newer Topic >>
An error in IJN CV capacities? - 11/12/2010 12:41:08 PM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
I am having a problem with Japanese aircraft carrier capacities. This may be due to confusion on my part about how reserve aircraft are dealt with, but might also be the product of an error in the capacities attributed to some of the carriers.

My difficulty stems from the fact that the scenarios I’ve looked at attribute a capacity of 71 aircraft to Hiryu and 72 aircraft to Kaga, which suggests that these two ships had substantially the same aircraft operating capability.

However, it seems to me that these figures credit Hiryu with too great a capacity and Kaga with one that is too small. Reputable sources attribute to Kaga a capacity of 91 aircraft including part-dismantled spares, whilst for Hiryu I have a source suggesting a capacity of 57 aircraft and 16 spares. However, I suspect this source understates Hiryu’s capability.

The Pearl Harbor OOB at the Navweaps site indicates that on 7 December 1941 Kaga despatched a combined total 27 attack planes, 27 carrier bombers and 18 fighters in the two attack waves, whilst retaining 9 fighters on CAP: 81 aircraft in total. From this I deduce that she had an operating capability of 81 modern aircraft. Taken in conjunction with the 91 aircraft total capacity usually attributed to her, this implies that she could carry a total of 10 spares in addition to her operational aircraft.

For Hiryu, the Navweaps OOB indicates that at Pearl Harbor she launched 18 attack planes, 18 carrier bombers and 15 fighters, retaining 9 fighters on CAP – a total of 60 aircraft. For Soryu, a carrier of similar size, the corresponding figures are 18, 18, 18 and 9, giving 63 aircraft in total.

It seems to me that one of the game’s capacity figures for these ships must be wrong. Using current game capacities, enlargement of Kaga’s hikokitai by the permitted maximum of 15% before air ops become impossible brings her operational capability up to 82 aircraft – one better than for the Hawaii Operation but with no remaining capacity for spares. But if you do the same with Hiryu, you raise her operational capability to a historically unfeasible 81 aircraft!

I am not clear as to how reserve aircraft in a carrier air unit affect that carrier’s capacity to operate aircraft. If reserves are counted in the number of aircraft embarked, then it seems to me that Kaga should be attributed a capacity of 91, permitting the historical complement of 81 aircraft plus up to 10 reserves. Hiryu should be treated as being equivalent to Soryu and have a capacity of not less than 71, so that she, like Soryu, can operate 63 aircraft and carry 8 to 10 reserves. However, if reserve aircraft do not count towards the carrier’s capacity, then Kaga’s capacity should be increased from 72 to 81, and Hiryu’s reduced to 63 – the same as for Soryu at present.

_____________________________



Post #: 1
RE: An error in IJN CV capacities? - 11/12/2010 2:29:45 PM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline
See this thread.

Each carrier is rated for CAP/Strike/Hanger/Reserve. CAP is the space available for fighters on deck alert while still allowing landings and launches. Strike is the space on which a deck load strike can be marshalled and still launch. Hanger is the space available for aircraft in the hangar. Reserve is the space available for partially disassembled aircraft. Effective carrier capacity is CAP+Hangar, with some weather risk and corrosion damage to the aircraft on the flight deck. Navies that didn't want to waste aircraft stuck to Hangar capacity. TheElf can probably criticise, but I was working with material available in the open literature 30 years ago.



_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to Local Yokel)
Post #: 2
RE: An error in IJN CV capacities? - 11/12/2010 4:57:20 PM   
Pascal_slith


Posts: 1643
Joined: 8/20/2003
From: in New England now
Status: offline
Dallas Isom in "Midway Inquest" indicated the complete launch schedule of the 6 carriers for PH.  These are laid on page 62 with note 50 for the chapter being important (Akagi's capacity was the same as Kaga but was reduced for the strike because it used space for fuel drums).  Hiryu and Soryu definitely had less capacity.  Can't go into the details just now.  I'll try copying it later.

I also suggest as sources "Sunburst" by Mark Peattie (of "Kaigun" fame) and "Titans of the Seas" by James and William Belote.


_____________________________

So much WitP and so little time to play.... :-(


(in reply to herwin)
Post #: 3
RE: An error in IJN CV capacities? - 11/12/2010 6:38:20 PM   
CV2

 

Posts: 168
Joined: 11/4/2010
Status: offline
Don't forget you can operate 115% so with the 72 plane Kaga + 15% (10) = 82 aircraft.

(in reply to Pascal_slith)
Post #: 4
RE: An error in IJN CV capacities? - 11/12/2010 7:06:40 PM   
Pascal_slith


Posts: 1643
Joined: 8/20/2003
From: in New England now
Status: offline
Here's the quote from Midway Inquest.

The nucleus of the Striking Force consisted of all six of Japan’s attack carriers:
Akagi (“Red Castle”) and Kaga (“Increased Joy”), Hiryu (“Flying Dragon”)
and Soryu (“Green Dragon”), and the new super-carriers Shokaku (“Soaring
Crane”) and Zuikaku (“Happy Crane”). They embarked 423 aircraft—405 “operational”
(that is, with pilots). Three hundred sixty planes were scheduled for
the attack on Pearl Harbor (note 49)—though only 355 would eventually be assigned
for the strike due to pilot disabilities—plus 45 operational planes for combat air
patrol, and the remaining 18 planes as “spares.” (The “operational” aircraft
complements appear to have been: 67 for Akagi,(note 50) 76 for Kaga, 57 for Hiryu, 56
for Soryu, 72 for Shokaku, and 72 for Zuikaku.) Supporting the carriers were the
two fast battleships Hiei and Kirishima, the heavy cruisers Tone and Chikuma
(which had been specially designed to carry five float planes each for reconnaissance),
and a screen of nine destroyers led by a light cruiser.

Here's note 50:

50. Akagi was designed to have the same aircraft capacity as Kaga, but for the Pearl
Harbor and Midway operations carried fewer planes. This was because its fuel oil tanks
were smaller than Kaga’s; to give it the same range, Akagi carried extra oil in drums,
which were stored in the lower hangar—reducing space for airplanes. Interview with
Tokayoshi Morinaga (torpedo plane pilot on Kaga), July 1993.


< Message edited by Pascal -- 11/12/2010 7:07:11 PM >


_____________________________

So much WitP and so little time to play.... :-(


(in reply to CV2)
Post #: 5
RE: An error in IJN CV capacities? - 11/12/2010 11:06:03 PM   
Q-Ball


Posts: 6847
Joined: 6/25/2002
From: Chicago, Illinois
Status: offline

quote:

ORIGINAL: Pascal

... to give it the same range, Akagi carried extra oil in drums,
which were stored in the lower hangar—reducing space for airplanes.


That sounds safe!


_____________________________


(in reply to Pascal_slith)
Post #: 6
RE: An error in IJN CV capacities? - 11/12/2010 11:39:13 PM   
VSWG


Posts: 3432
Joined: 5/31/2006
From: Germany
Status: offline
What could possibly go wrong?! 

_____________________________


(in reply to Q-Ball)
Post #: 7
RE: An error in IJN CV capacities? - 11/13/2010 12:22:41 AM   
DivePac88


Posts: 3123
Joined: 10/9/2008
From: Somewhere in the South Pacific.
Status: offline
Japanese figures (from translation by Tone),

AKAGI; as built 60, as reconstructed 91 (63 operational).

KAGA; as built 60, as reconstructed 91 (72 operational).

SORYU; 68 (57 operational).

HIRYU; 73 (59 operational).



< Message edited by DivePac88 -- 11/13/2010 12:23:10 AM >


_____________________________


When you see the Southern Cross, For the first time
You understand now, Why you came this way

(in reply to VSWG)
Post #: 8
RE: An error in IJN CV capacities? - 11/13/2010 12:46:02 AM   
JeffroK


Posts: 6332
Joined: 1/26/2005
Status: offline
From Shattered Sword by Parshall & Tully

Akagi     91 total when recommisioned, 63 operational (approx) in 1941

Kaga      91 total when recommisioned, 72 operational (approx) in 1941

Soryu     68 total when commisioned, 57 operational (approx) in 1941

Hiryu      73 total when recomisioned, 59 operational (approx) in 1941

Dont forget that different aircraft occupy different amounts of space, so the shape & size of the airgroups affects the number of aircraft carried.


_____________________________

Interdum feror cupidine partium magnarum Europae vincendarum

(in reply to DivePac88)
Post #: 9
RE: An error in IJN CV capacities? - 11/13/2010 2:48:40 AM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
A big problem in any discussion of Japanese carrier capacities is that none of the available sources of information can be treated as dispositive. I guess there may be only one non-Japanese historian who can speak authoritatively about how many operational aircraft were embarked in any one of the carriers that attacked Pearl Harbor, and his book on the subject doesn’t seem likely to reach the shelves in less than a year from now. Even he has indicated that official records are beset with issues, in particular:

- there are a number of discrepancies between the Official War History aircrew roster for the Hawaii Operation and the air group records from which that roster has been derived;

- apparently there is no surviving air group record for the CAP flown from Kaga on 7 December.

FWIW the Official War History tabulates aircrew for 35 aircraft flown from Kaga in each of the two attack waves. If the Official History were to prove accurate to that limited extent, it means that on 7 December Kaga was operating a minimum of 70 aircraft committed to the attack itself, in addition to which she would have contributed an indeterminate number of carrier fighters to ‘garrison’ over Kido Butai itself. At the moment it looks as though no means can be found for establishing what that number was. 3? 6? 9? Even if the CAP contribution was confined to a single shotai of 3 aircraft that still makes Kaga’s total of operational aircraft larger than the approximation offered by Parshall and Tully.

My guess is that Dallas Isom may have got the figure of Kaga’s aircraft right at 76, if only because the retention of only one shotai of fighters for CAP over the task force is so perilously small a number, whilst the holding back of two three plane elements allows for relief and reinforcement of the standing patrol and a reserve against operational casualties. But I accept this is purely a guess.

I also accept that, due to increases in the size of aircraft embarked, Kaga’s maximum capacity may have shrunk somewhat from the figure of 91 at the time of her reconstruction. However, I find it hard to believe that this accounts a reduction of 19 in the number of aircraft that can theoretically be embarked – that’s a capacity loss of almost 20%!

In general, I see little here that is much at odds with my first thoughts that Kaga’s capacity in the game is understated whilst Hiryu’s is overstated. And I would still be grateful for clarification of whether reserves affect the total number of aircraft that can be embarked in a carrier.

_____________________________




(in reply to JeffroK)
Post #: 10
RE: An error in IJN CV capacities? - 11/13/2010 7:50:59 AM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: JeffK

From Shattered Sword by Parshall & Tully

Akagi     91 total when recommisioned, 63 operational (approx) in 1941

Kaga      91 total when recommisioned, 72 operational (approx) in 1941

Soryu     68 total when commisioned, 57 operational (approx) in 1941

Hiryu      73 total when recomisioned, 59 operational (approx) in 1941

Dont forget that different aircraft occupy different amounts of space, so the shape & size of the airgroups affects the number of aircraft carried.



The number of aircraft that could be operated depended on spot size. For pictures, see this link. What I did in my analysis thirty years ago was draw layouts of the various flight decks and hangar decks, allowing me to explore how many planes could fit in various operational scenarios with folded and unfolded wings. See Friedman for a discussion.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to JeffroK)
Post #: 11
RE: An error in IJN CV capacities? - 11/13/2010 8:12:38 AM   
Sardaukar


Posts: 7576
Joined: 11/28/2001
From: Finland/Israel
Status: offline

quote:

ORIGINAL: herwin

The number of aircraft that could be operated depended on spot size. For pictures, see this link. What I did in my analysis thirty years ago was draw layouts of the various flight decks and hangar decks, allowing me to explore how many planes could fit in various operational scenarios with folded and unfolded wings. See Friedman for a discussion.



I think you mean the number of aircraft that could be operated SIMULTANEOUSLY depends on spot size? As Friedman says, actual aircraft capacity carried little explicit weight. Usually "deck-load strike" is less than practical number of planes CV can operate. There is also the matter with elevator numbers and their position. So, CV could launch full deck strike and then start to spot for second, but we also have to allow some for maintaining CAP, unless there was designated CV for that. So calculations game-wise would be quite tricky, to fit with all probabilities. It's safe to say that no CV operated with absolute maximum of planes they could operate theoretically (maybe in ferry mission), because it was impossible in practice.

I think they made good compromise with historical figures fitted into AE game engine.


_____________________________

"To meaningless French Idealism, Liberty, Fraternity and Equality...we answer with German Realism, Infantry, Cavalry and Artillery" -Prince von Bülov, 1870-


(in reply to herwin)
Post #: 12
RE: An error in IJN CV capacities? - 11/13/2010 9:01:46 AM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: Sardaukar


quote:

ORIGINAL: herwin

The number of aircraft that could be operated depended on spot size. For pictures, see this link. What I did in my analysis thirty years ago was draw layouts of the various flight decks and hangar decks, allowing me to explore how many planes could fit in various operational scenarios with folded and unfolded wings. See Friedman for a discussion.



I think you mean the number of aircraft that could be operated SIMULTANEOUSLY depends on spot size? As Friedman says, actual aircraft capacity carried little explicit weight. Usually "deck-load strike" is less than practical number of planes CV can operate. There is also the matter with elevator numbers and their position. So, CV could launch full deck strike and then start to spot for second, but we also have to allow some for maintaining CAP, unless there was designated CV for that. So calculations game-wise would be quite tricky, to fit with all probabilities. It's safe to say that no CV operated with absolute maximum of planes they could operate theoretically (maybe in ferry mission), because it was impossible in practice.

I think they made good compromise with historical figures fitted into AE game engine.



I think I agree. Flight deck operations were choreographed in detail within the constraints of flight and hangar deck layouts and aircraft planform. What I did was set up CAP operations to see how large those could be, and set up a deckload strike for that. I then packed the aircraft into the hangar layout to see what could be reasonably kept there. Reserves were from other sources. Typically, a deckload strike was half the aircraft complement.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to Sardaukar)
Post #: 13
RE: An error in IJN CV capacities? - 11/14/2010 2:11:14 AM   
John Lansford

 

Posts: 2662
Joined: 4/29/2002
Status: offline
I thought the Japanese didn't spot planes on-deck until ready to launch, unlike the USN.  That reduced their operational tempo, and caused delays in launching whenever planes in the air had to land suddenly since any new planes to launch had to use the elevators to get on deck.  IJN carriers should be rated for plane capacity by the size of their hangars, not the size of their flight deck.

(in reply to herwin)
Post #: 14
RE: An error in IJN CV capacities? - 11/14/2010 3:46:38 AM   
CV2

 

Posts: 168
Joined: 11/4/2010
Status: offline
Or you could just rate them by how many planes they historically operated.

(in reply to John Lansford)
Post #: 15
RE: An error in IJN CV capacities? - 11/14/2010 7:28:56 AM   
mike scholl 1

 

Posts: 1265
Joined: 2/17/2010
Status: offline

quote:

ORIGINAL: John Lansford

I thought the Japanese didn't spot planes on-deck until ready to launch, unlike the USN.  That reduced their operational tempo, and caused delays in launching whenever planes in the air had to land suddenly since any new planes to launch had to use the elevators to get on deck.  IJN carriers should be rated for plane capacity by the size of their hangars, not the size of their flight deck.



USN carriers could perform a "continuous launch" of their entire air groups because they could "run up the engines" of A/C in the hanger decks. The Japanese could not do this do to the design of their CV's. They had to spot a strike on deck, run up the engines, launch that strike, bring up another deckload of planes, run them up, and launch a second strike.

(in reply to John Lansford)
Post #: 16
RE: An error in IJN CV capacities? - 11/14/2010 7:41:34 AM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: John Lansford

I thought the Japanese didn't spot planes on-deck until ready to launch, unlike the USN.  That reduced their operational tempo, and caused delays in launching whenever planes in the air had to land suddenly since any new planes to launch had to use the elevators to get on deck.  IJN carriers should be rated for plane capacity by the size of their hangars, not the size of their flight deck.


That didn't mean they couldn't; just that they didn't. Aircraft left on deck were vulnerable to salt water corrosion and weather. The RN moved from keeping their aircraft below to a deck park during the war as aircraft became more available. The same option was available to the IJN.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to John Lansford)
Post #: 17
RE: An error in IJN CV capacities? - 11/14/2010 11:36:03 AM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
Some support for Dallas Isom’s contention that Akagi took a reduced aircraft complement to Hawaii is to be found in the War History aircrew roster, to which I referred earlier. If correct, it reveals that Akagi despatched 33 aircraft in the first attack wave, and only 27 in the second. On the Isom figures that would leave 7 fighters for CAP over Kido Butai.

Morinaga’s recollection that Akagi was carrying extra fuel in the lower hangar is tantalising because it begs the question ‘which lower hangar?’ Did he mean the second level hangar or the third? The third hangar was very much smaller than the other two, but the most likely place for storage of additional fuel drums.

This leads conveniently to consideration of the Japanese carriers’ hangar area. Referring to Parshall and Tully’s Shattered Sword, Akagi is credited with 93,000 square feet for the upper and middle level hangars combined, and 8,515 square feet for the lower level hangar. For Kaga, the corresponding figures are 108,240 square feet and 5,568 square feet. Hiryu and Soryu had only two hangar levels; they lacked the small third level hangar of the bigger carriers. Parshall and Tully credit both Hiryu and Soryu with same overall hangar area: 61,740 square feet.

There’s no getting away from this: Hiryu and Soryu had only 66% of the hangar area of Akagi and 57% of that of Kaga – and that’s leaving out of account the additional space of the two big carriers’ third level hangar. Akagi’s hangar area was approximately 86% of that for Kaga. Yet, according to the capacity figures attributed to the carriers in the game, Kaga can accommodate only 72 aircraft against Akagi’s 81, notwithstanding her significantly larger hangars. Meanwhile Hiryu, with a hangar area only two thirds the size of Kaga, can accommodate only one fewer aircraft.

The number of aircraft in a deckload spot may be all very well as a measure of a carrier’s striking capacity, but overall capacity and the limit it places on total aircraft embarked has greater relevance to that ship’s ability to remain in a fight once attrition has started to take its toll. In the CHS version of WitP, Shokaku, Zuikaku, Kaga and Akagi were each given a capacity of 84 aircraft, whilst Hiryu and Soryu had capacities of 71 and 70 respectively. In AE these have been altered as follows:

Hiryu: no change
Akagi: -3
Soryu: -7
Kaga, Shokaku and Zuikaku: -12

It appears that something prompted the developers to make these reductions, but I can see no obvious rationale for them. In particular, it makes no sense to me that Hiryu, with only two-thirds of Kaga’s hangar area, should be treated as having substantially the same capacity. Even more inexplicable is a decision that Kaga, with bigger hangars than Akagi, should have her capacity reduced by four times the amount of Akagi’s reduction.

I would welcome an explanation of these reductions, and also one about the impact, if any, of reserve aircraft upon a carrier’s capacity.

<edit> Corrected spelling </edit>

< Message edited by Local Yokel -- 11/14/2010 11:37:02 AM >


_____________________________




(in reply to herwin)
Post #: 18
RE: An error in IJN CV capacities? - 11/14/2010 2:02:54 PM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline
The spot size of an aircraft should be about wing span folded times length times about 2/3rds, except for the Grummans, which folded differently. For example, an A6M was about 36x30*2/3 = 720 square feet. Allowing that you couldn't pack them that close, 9 A6Ms occupied about 6600 square feet of hangar space. Vals took up about the same space, while Kates, with folding wings required about 5000 square feet of hangar space (9*25*30*2/3) for nine aircraft. At launch, the Hiryu could position 2 Kates, 2 Vals, or 2-3 Zeros in a row across the flight deck. With a minimum takeoff distance of about 250 (normal)-300 (overload) feet, and a flight deck length of 711 feet, a deckload strike would be 400-450 feet of aircraft arrayed in pairs. That works out to 10x2 attack aircraft and 5x(2-3) fighters. The Shokaku/Akagi/Kaga were good for two or three across and 500-550 feet of aircraft. Figure a range of 36-54 (average 45) aircraft in a deckload strike. American carriers were similar to the Shokaku. Landing distance was about 400 feet, so a standing CAP required 400 feet for landing, 250 feet for takeoff, and had perhaps 150 feet for aircraft operations on the flight deck.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to Local Yokel)
Post #: 19
RE: An error in IJN CV capacities? - 11/14/2010 6:01:53 PM   
mike scholl 1

 

Posts: 1265
Joined: 2/17/2010
Status: offline

quote:

ORIGINAL: herwin


quote:

ORIGINAL: John Lansford

I thought the Japanese didn't spot planes on-deck until ready to launch, unlike the USN.  That reduced their operational tempo, and caused delays in launching whenever planes in the air had to land suddenly since any new planes to launch had to use the elevators to get on deck.  IJN carriers should be rated for plane capacity by the size of their hangars, not the size of their flight deck.


That didn't mean they couldn't; just that they didn't. Aircraft left on deck were vulnerable to salt water corrosion and weather. The RN moved from keeping their aircraft below to a deck park during the war as aircraft became more available. The same option was available to the IJN.



Not quite the same, Herwin. The IJN didn't have the American Industrial Monster cranking out so many A/C that they could afford to scrap them if they were damaged by weather.

(in reply to herwin)
Post #: 20
RE: An error in IJN CV capacities? - 11/14/2010 9:05:52 PM   
Saburo Kurusu


Posts: 67
Joined: 7/4/2010
From: Imperial Japanese Embassy, Berlin
Status: offline
Well, at least everyone might feel free to change the numbers via the editor in the way he assumes to really fit reality best...... But I think the developers might have done that to the best possible knowledge. I also have three books with three different numbers on this, that's annoying, I can understand the poster very much...... I think in the end a definite answer to this is perhaps impossible......

_____________________________

"Santa Maya must be liberated by any means necessary. Even diplomacy if it should come to it."

British PM Sir Mortimer Chris in "Whoops Apocalypse"


(in reply to mike scholl 1)
Post #: 21
RE: An error in IJN CV capacities? - 11/15/2010 12:26:08 PM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
I have extrapolated some of the figures given in Herwin’s post #19 in an attempt to relate space required by carrier aircraft to the hangar space available.

I assumed a complement of 81 aircraft for Kaga broken down into three 9-plane chutai apiece of A6M, D3A and B5N. Applying Herwin’s figures, 27 A6M and 27 D3A require 19,800 square feet apiece, whilst the 27 B5N require 15,000 square feet. Combined, these give a total of 54,600 square feet. This is slightly more than one half of the available hangar space provided by Kaga’s upper and middle level hangars. Put another way, it is almost possible to house the carrier’s entire airgroup in one of her two principal hangars.

If you reduce the airgroup size to the game maximum for Kaga of 72 aircraft by taking away one chutai either of A6M or D3A, the hangar space requirement drops to 48,000 – substantially less than half the available hangar space.

I have two reservations about the figures given by Herwin as the space required for individual carrier aircraft. First, I think he may have underestimated the area taken up by a single D3A. I also suspect that there may be a significant difference between the minimum theoretical area into which an aeroplane can be crammed and the minimum area required for practical handling purposes – you can’t park an aircraft by moving it sideways! I am aware that Herwin made some allowance for this by increasing the area required for parking each 9-plane element, but I think that allowance may not been large enough.

Even if one allows a generous increase in the amount of hangar space required for parking a chutai of any given aircraft model, you still seem to be left with ample space within Kaga’s hangars. On Herwin’s figures a single A6M or D3A takes up about 720 square feet, a B5N about 500. Contrast that with a figure of 1,336 square feet per individual aircraft if the upper and middle level hangars’ area is divided evenly amongst 81 aircraft. All this without any resort being made to the additional area of 5,568 square feet that is available in the lower level hangar.

The conclusion I draw from this is that there is no obvious reason for limiting Kaga’s capacity to 72 aircraft by reference to the space available within her hangars. Even with a manoeuvring/parking area per aircraft about double the space allowed for by Herwin, I see no reason to think that Kaga could not have accommodated an hikokitai of 81 1941-era aircraft in her hangars. This implies that some other reason was adopted by the developers for constraining her capacity to 72. What can that reason be?

I’m well aware that I can modify the data to restore Kaga’s capacity to a figure closer to Akagi’s, if I think it better reflects her historical capability. But I would much prefer to understand why the developers limited her capacity to 72 when both the historical record (91 aircraft capacity) and calculations of her available hangar area point to a different conclusion. So far, the only explanations I have seen suggested for such a reduction have been related to such factors as the maximum size strike she could spot. This, however, is to confuse her ability to conduct various forms of air operations with her staying power over a battle that may last several days, for which total aircraft embarked (and therefore maximum capacity) becomes much more significant.

Sad to say, still no response on my question about how reserve aircraft are related to carrier capacity.

_____________________________




(in reply to Saburo Kurusu)
Post #: 22
RE: An error in IJN CV capacities? - 11/15/2010 1:22:36 PM   
Fishbed

 

Posts: 1821
Joined: 11/21/2005
From: Beijing, China - Paris, France
Status: offline
Tell me if I am wrong (for I don't have the book with me and it's been a very long time), but I seem to remember that Shattered Sword (or was it Sunburst?) had an interesting graph of some IJN carrier hangar storage in its annex (I think it was Akagi's) with its airgroup as an overlay seen from the top. Maybe it could answer some questions, or at least give a better picture of the whole thing.

_____________________________


(in reply to Local Yokel)
Post #: 23
RE: An error in IJN CV capacities? - 11/15/2010 1:35:41 PM   
DivePac88


Posts: 3123
Joined: 10/9/2008
From: Somewhere in the South Pacific.
Status: offline
Local Yokel,

you have to remember that the Hanger space figures provided, did not take into account the lift-wells. The spaces on either side of the lift-wells could not be used for aircraft storage, and were generally used for aircraft and engine parts. Also some of the older carriers had lifts that could not handle all aircraft types available, and this dictated the storage arrangements also.

_____________________________


When you see the Southern Cross, For the first time
You understand now, Why you came this way

(in reply to Local Yokel)
Post #: 24
RE: An error in IJN CV capacities? - 11/15/2010 1:36:03 PM   
spence

 

Posts: 5283
Joined: 4/20/2003
From: Vancouver, Washington
Status: offline
It's "Shattered Sword" but it's only a partial view of the hangar deck. It's pretty crowded in there. Tall people would get lots of bumps on their heads unless they were very careful. IIRC there is considerable text describing hangar deck operations.


(in reply to Fishbed)
Post #: 25
RE: An error in IJN CV capacities? - 11/15/2010 2:34:14 PM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline
Thanks for the critical comments. The other thing is that Japanese carriers had workshops along the edges of the hangar deck--much like RN carriers. I did the original work 30 years ago, and my notes are back in America in the condo (if they still exist). I suspect the big constraints were flight deck operations and aircraft availability.

Shattered sword shows 13 Zeros and Kates ranged between the amidships and rear lifts, apparently on Hiryu or Soryu. Four rows of three aircraft plus one. The A6M2 had a wingspan of 36 feet 2" with wingtips folded and a length of 29 feet 9 inches. Three took up about 75 by 30 = 2250 square feet. The B5N2 had a wingspan of 24-25 feet folded and a length of 33 feet 9.5 inches. Seven in the picture took up a bit more than 75 by 70 = 5250 square feet. Based on the figure, 61740 minus the space for the three elevators and adjoining shops (about 75x30x6=13500 square feet) was about enough space for 48000/750 = 64 aircraft. Sounds like the quoted capacity. The flight deck was 711 x 75 feet. Subtract 650 feet for landing and takeoff operations gives 61 x 75 = room for six A6M2s in a deck park. Theoretical maximum of 70 aircraft.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to Local Yokel)
Post #: 26
RE: An error in IJN CV capacities? - 11/15/2010 2:45:12 PM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
DivePac makes the entirely valid point that the lift wells and the space laterally adjacent to them have to be left out of any reckoning of hangar space, and Spence rightly directs attention to Figure 7-1 in Shattered Sword. The authors don't say which carrier is being illustrated, but judging by the offset of the centre lift and the sponson arrangement I'd say it's a plan of Hiryu, whose hangar area is shown by shading on Fig. 17-6.

The plan of the aft section of Hiryu's hangar (assuming that's correct) shows 13 aircraft. Given that this is a double deck hangar, a similar number of aircraft would be accomodated on the deck above or below - add another 13 aircraft: 26 in total so far. Ahead of the middle lift shown in the plan there's another section of double deck hangar of comparable length - add another 26 aircraft, and we are up to 52. Finally, there's a further section of hangar ahead of the forward lift. The upper level of this is longer than the aft section illustrated in Shattered Sword, but the double-deck portion below is shorter. The upper area was probably used for A6M's - from memory their cannon arming station was near the front of the carrier and it makes sense to bring them up to the flight deck via the forward lift. Even if this forward section can accomodate, say, only 20 rather than 26 aircraft, the total has gone up to 72. This in a carrier having a hangar area only 57% of that of Kaga, so when scaling up to the hangar space available in the larger carrier I have no difficulty in visualising capacity for more than eighty aircraft.

Once again, this assessment of the available hangar space in Kaga is without recourse to the small lower level hangar. Indeed, if my extrapolation from the Shattered Sword plan of the number of aircraft that Hiryu can take into her hangars is correct, Hiryu herself has an aircraft capacity equal to that attributed to Kaga in the game.

_____________________________




(in reply to spence)
Post #: 27
RE: An error in IJN CV capacities? - 11/15/2010 3:03:40 PM   
Local Yokel


Posts: 1494
Joined: 2/4/2007
From: Somerset, U.K.
Status: offline
My previous post made before I saw Herwin's.

Harry, the workshops flanking the hangars may well have a bearing on available space, although in the midships hangar section we are dealing with the area of maximum beam. So 72 in the hangar may be too high an estimate. I think we are moving closer on the area required per aircraft; it's a pity we don't have a full hangar plan with which the part plan in Shattered Sword can be compared.

Nevertheless, when the substantially greater size of Kaga is taken into account I don't see a reason to revise my conclusion that she could take more than 72 aircraft into her hangars.

Incidentally, I think the plan in Shattered Sword is showing D3A carrier bombers rather than A6M's. The obvious place to strike below the Zeroes is the forward end, given that they will normally go to the front of the flight deck spot because of their short take-off run.

_____________________________




(in reply to herwin)
Post #: 28
RE: An error in IJN CV capacities? - 11/15/2010 4:10:36 PM   
spence

 

Posts: 5283
Joined: 4/20/2003
From: Vancouver, Washington
Status: offline
quote:

Incidentally, I think the plan in Shattered Sword is showing D3A carrier bombers rather than A6M's. The obvious place to strike below the Zeroes is the forward end, given that they will normally go to the front of the flight deck spot because of their short take-off run.


They are not D3As since the Vals did not have folding wings. Folding wings were inherently weaker wings and dive bombers needed every bit of the strength of a one-piece wing in order to withstand the G forces of pullout (that is; in order to make more than one dive per airframe ).

The Ryujo and other CVLs never carried D3As because they were much larger to accommodate in the hangar and on the elevator because of their non-folding wings.

(in reply to Local Yokel)
Post #: 29
RE: An error in IJN CV capacities? - 11/15/2010 4:16:12 PM   
herwin

 

Posts: 6059
Joined: 5/28/2004
From: Sunderland, UK
Status: offline

quote:

ORIGINAL: spence

quote:

Incidentally, I think the plan in Shattered Sword is showing D3A carrier bombers rather than A6M's. The obvious place to strike below the Zeroes is the forward end, given that they will normally go to the front of the flight deck spot because of their short take-off run.


They are not D3As since the Vals did not have folding wings. Folding wings were inherently weaker wings and dive bombers needed every bit of the strength of a one-piece wing in order to withstand the G forces of pullout (that is; in order to make more than one dive per airframe ).

The Ryujo and other CVLs never carried D3As because they were much larger to accommodate in the hangar and on the elevator because of their non-folding wings.



The aircraft with the folding wingtips were A6M2s. The wingtips were removed in later models. The ones with the folding wings were B5N1s or B5N2s.

_____________________________

Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com

(in reply to spence)
Post #: 30
Page:   [1] 2   next >   >>
All Forums >> [New Releases from Matrix Games] >> War in the Pacific: Admiral's Edition >> An error in IJN CV capacities? Page: [1] 2   next >   >>
Jump to:





New Messages No New Messages
Hot Topic w/ New Messages Hot Topic w/o New Messages
Locked w/ New Messages Locked w/o New Messages
 Post New Thread
 Reply to Message
 Post New Poll
 Submit Vote
 Delete My Own Post
 Delete My Own Thread
 Rate Posts


Forum Software © ASPPlayground.NET Advanced Edition 2.4.5 ANSI

0.230