Naval CAP (Combat Air Patrol) Doctrine in WW2

[wingedhussar]

All:

Some friends and I are having a discussion around Naval CAP Doctrine during WW2. Did Aircraft Carriers have a doctrine for how planes covered the fleet? We've looked across the 'net and in to as many books as possible, finding information on doctrine for air to ground cover, but nothing so far on how the US protected the carriers.

Any help?

Thanks,
Phil

 

[Nikademus]

USN prewar naval CAP doctrine entailed the use of airborne fighter lookout patrols to detect incoming enemy groups. Since the primary mission of the CAP was the destruction of enemy search planes and strikes, this took up most of the available fighter assets. Once detected, the fleet would be warned and fighters vectored onto the threat for attack.


1942 saw the deployment of shipboard air search radar and the adoption of British techniques which saw the use of an FDO (Fighter Direction Officer) to exercise direct control of fighter operations. (centralized control for the TF)

Basic CAP organization were fighter divisions with their component two-plane sections. When in areas where enemy activity might be likely, the carriers retained in the air a full division of 4-6 planes. Use of radar could allow the FDO to deploy additional assets into the air in time (hopefully) to make an intercept. Standing patrol altitudes varied depending on weather conditions and cloud cover. 20k was usually an upper limit.

CAP doctrine evolved continuously as combat lessons were absorbed so there's much much more to the above, itself only a real basic overview. For more details I'd recommend the source of the above info: Lundstrom; The First Team Vol I (and vol II)

edit: Another curiosity you'll read about if you get the above was the use of SBD scout bombers as ersatz CAP fighters. Pre and early war USN CV's having roughly 1/2 the number of fighters they'd eventually ship later in the war there were never enough to do all the tasks needed (Escort and CAP) so some of the SBD's were utilized for "anti-torpedo plane patrols" in order to assist the fighters (and allow them to fly higher alt patrols to protect against dive bombers) The practice was mostly discontinued after the Coral Sea battle due to heavy losses suffered at the hands of escorting Zeros. The SBD's didn't do bad vs. enemy B5N's, but given their own losses it was quickly realized that the best solution was more genuine fighter aircraft. The folding wing F4F-4 helped alot that area.

 

[renrich]

Good post Nik, I see you are a disciple of Lundstrom. They are excellent books.

 

[Freebird]

1942 saw the deployment of shipboard air search radar and the adoption of British techniques which saw the use of an FDO (Fighter Direction Officer) to exercise direct control of fighter operations. (centralized control for the TF)

losses it was quickly realized that the best solution was more genuine fighter aircraft. The folding wing F4F-4 helped alot that area.

Interesting, and a good thing that the airgroup at least was learning something from British experience. (Unlike Adm. King!) Now if only the British would have taken some ideas from the Americans too...

I've wondered why the British had so much trouble getting a decent number of fighter CAP on to their carriers, whether it was a problem with doctrine or with equipment. For example, on the "Pedestal" convoy from Gibraltar to Malta in Aug '42 they had 2 carriers for escort, (after the 3rd carrier "Eagle" was lost to a U-boat) but the convoy had heavy losses due to Axis air attack. A 4th carrier "Furious" had launched 40 Spitfires from 600 miles out to fly to Malta, then returned to Gibraltar. For air cover the "Indomitable" had 24 SeaHurricanes, 10 Martlets (Wildcats) 14 Albacore TB's. The "Victorious" had 16 Fulmars, 6 SeaHurri's, 14 Albacores.

The convoy had the same trouble as the Japanese at Midway, after disrupting a wave of enemy TB's, Ju 87's were able to hit "Indomitable" several times, and although because of the armoured deck it didn't sink, but the flight deck ( 40 aircraft) were now unusable. The convoy's CAP was now reduced to 8 Hurricanes, 3 Martlets 10 Fulmars.

I would have thought it would have been better to load the Victorious with as many Martlet's SeaHurri's as possible (the same ship had 60 Wildcats operating in 1943 when in the Pacific with the US fleet) to provide a stronger CAP. If it was really thought vital to have the Albacore TB's along, they should have been flown from Gibraltar to land on the "Furious" after launching the Spitfires, as the Italian fleet would not have been in range until after this time anyways.

I think that the British had gotten a large # of Wildcats delivered in 1941, did they not have enough or was it just not RN doctrine to have a large CAP, even when expecting heavy air attack?

 

[renrich]

The air groups on the US carriers typically comprised one VT, two VSB and one VF squadron early in the war. When they realised that they needed more VFs there was actually a shortage of combat ready Wildcats for a while as well as qualified pilots. That was one reason some SBD drivers converted over to Wildcats. One reason there was a shortage of fighters was because the Brits were getting some. Another reason was that thanks to the Brit's stubborness about wanting six guns on the F4F4, which in my opinion was stupid, the armament installation had to be redesigned thus slowing down the assembly line. Later the Navy went back to the four guns in the FM. The things we do for our allies!LOL

 

[Freebird]

One reason there was a shortage of fighters was because the Brits were getting some. Another reason was that thanks to the Brit's stubborness about wanting six guns on the F4F4, which in my opinion was stupid, the armament installation had to be redesigned thus slowing down the assembly line.

What time frame are you referring to Ren? 1941? or 1942?

 

[Glider]

The air groups on the US carriers typically comprised one VT, two VSB and one VF squadron early in the war. When they realised that they needed more VFs there was actually a shortage of combat ready Wildcats for a while as well as qualified pilots. That was one reason some SBD drivers converted over to Wildcats. One reason there was a shortage of fighters was because the Brits were getting some. Another reason was that thanks to the Brit's stubborness about wanting six guns on the F4F4, which in my opinion was stupid, the armament installation had to be redesigned thus slowing down the assembly line. Later the Navy went back to the four guns in the FM. The things we do for our allies!LOL

Be fair Renrich. There were a lot more changes in the Wildcat than just the 6 x HMG's. The RN did accept a delay in delivery but the main reason was to get the folding wings which is a change worth having. Even then the RN accepted the first of the Martlet II's with fixed wing to keep up deliveries.

 

[Freebird]

Be fair Renrich. There were a lot more changes in the Wildcat than just the 6 x HMG's. The RN did accept a delay in delivery but the main reason was to get the folding wings which is a change worth having. Even then the RN accepted the first of the Martlet II's with fixed wing to keep up deliveries.

When did the RN get the first Marlet II's with the folding wings? Did the first SeaHurri II's have folding wings or was that only later?

 

[Glider]

The first folding wing Martlet IIs were delivered in August 1941, the other big changes were of course the extra guns but also armour and Self Sealing fuel tanks.
These were all needed to make the plane fully combat worthy.

Re the Sea Hurricane II I am not so sure about re dates.

 

[Freebird]

The first folding wing Martlet IIs were delivered in August 1941, the other big changes were of course the extra guns but also armour and Self Sealing fuel tanks.
These were all needed to make the plane fully combat worthy.

Re the Sea Hurricane II I am not so sure about re dates.

I couldn't find the info for the first date for folding-wing SeaHurri's

I found the listing for the Seafire which had folding wings, beginning in March 1942, with 165 delivered. In June '42 a further 375 Mk. IIC's were delivered, so I wonder why they were not available for such an important mission as Pedestal. Perhaps the Fulmar was as good a fighter as the Seafire? {I'm kidding!!!}

The Supermarine Spitfire

 

[maxs75]

The Sea Hurricane never had folding wings. Only Seafire had, from the MkII variant.

Max

 

[Freebird]

Did the US have plans for a folding wing Wildcat already in the works? Or was the version that the British ordered the first folding wing fighter in the USN?

 

[renrich]

1942 is the period I am referring to. I am not being truly critical of our Brit cousins but the switch to six guns did cause a delay in production while the redesign took place and I feel the change was not only unecessary and wrongheaded, but was a negative. My opinion but also many naval aviators including Thach(he said "if you can't hit with four you will miss with six"). In an AC like Wildcat four 50s with 400 rounds each has got to be prefarable to six 50s with 240 rounds each. Perhaps the superior training of the US Navy pilots was responsible for that attitude. The folding wing was, I believe, an improvement desired by the USN so that more AC could be carried. I do not think that was initiated by the RN. The changes to the F4F which resulted in the F4F4 added around 1000 pounds to the weight.

 

[Glider]

1942 is the period I am referring to. I am not being truly critical of our Brit cousins but the switch to six guns did cause a delay in production while the redesign took place and I feel the change was not only unecessary and wrongheaded, but was a negative. My opinion but also many naval aviators including Thach(he said "if you can't hit with four you will miss with six"). In an AC like Wildcat four 50s with 400 rounds each has got to be prefarable to six 50s with 240 rounds each.

I don't know where the view that the redesign for the additional two guns was the only reason for the delay in production comes from. As mentioned in the earlier posting that particular version had a number of changes only one of which was the additional two guns.
I think its also worth remembering that Grumman had already designed the Wildcat to have six guns well before the RN became involved. The first nation to order the Wildcat were the French and they specified 6 x LMG, not 4 x HMG.
When the British took over the contract the British initiated the change on those aircraft to 4 x HMG. Clearly there is a big difference between 6 x LMG and 6 x HMG but the groundwork as to where to put the guns, had already been done.

Re wrongheaded its a debate, but its worth remembering that the P51 was upgunned from 4 to 6 HMGs and by European Standards, 4 x HMG was light for a fighter.

 

[Freebird]

I don't know where the view that the redesign for the additional two guns was the only reason for the delay in production comes from. As mentioned in the earlier posting that particular version had a number of changes only one of which was the additional two guns.
I think its also worth remembering that Grumman had already designed the Wildcat to have six guns well before the RN became involved. The first nation to order the Wildcat were the French and they specified 6 x LMG, not 4 x HMG.
When the British took over the contract the British initiated the change on those aircraft to 4 x HMG. Clearly there is a big difference between 6 x LMG and 6 x HMG but the groundwork as to where to put the guns, had already been done.

Re wrongheaded its a debate, but its worth remembering that the P51 was upgunned from 4 to 6 HMGs and by European Standards, 4 x HMG was light for a fighter.

Yes it would seem to me that the design of folding wings would involve more design work than putting (back - as Glider says) the 2 extra guns. And while it may be true that 4 guns was fine for PTO where the Japanese aircraft were of a lighter design IIRC, but the stronger German AC could withstand MG's better.

 

[renrich]

You gentlemen have forced me to go back into my references to back up my (perhaps) poorly chosen words. From Dean's chronology of the Wildcat in "America's 100 thousand" In March of 1940, a contract change by the Navy provides for installation of wing folding on an F4F3. That is the first mention of wing folding on the Wildcat. As you know a Martlet shot down a vaunted(by some) JU 88 on Christmas Day, 1940. 4 guns seems to have been plenty then. Interestingly all the Wildcats at Coral Sea were F4F3s. No folding wings and 4 guns. all the Navy Wildcats at Midway were F4F4s with manual folding wings and 6 guns. From Lundstrom "The First Team" page 435. " Because of production difficulties, modern aircraft were slow in getting to the fleet and newly formed squadrons often languished with just a few planes." Page 436-"New AC deliveries and new flight school graduates have done little more than balance operational and battle losses of active carrier planes and pilots." These statements are in June after Midway. Back to Dean-about 75% of all Wildcats were built by Eastern(GM) Back to Lundstrom-On 18 April, BuAer signed a contract with Eastern to produce the FM1 an exact copy of the F4F4. Deliveries expected in late summer 1942. Meanwhile the Bureau seemed to hedge it's bet with an order for an additional 100 fixed wing F4F3s with 4 guns. The Bureau seemed to feel guilty about the 6 gun planes with the extra weight and reduced ammo load. The decision to go with six guns was a desire for standardization in production "because of the British insistence on 6 guns." "Upon seeing the installation which Grumman cooked up for 6 guns, this Section as well as Armament has realised we made a mistake, but there again it is too late to tamper with production at this time." A little later they did decide to tamper with production. "Armament labored to redesign the F4F4s folding wings to accomodate four guns instead of six and with 430 rounds each instead of 240. The resulting AC , which included a few minor changes tipped the scales about 500 lbs lighter than a standard f4f4." The Bureau did not tamper with Grumman's production but shocked Eastern on 14 June, 1942 by issuing a change order directing that the eleventh production FM1 and those following had to feature a redesigned 4 gun battery. Therefore I cannot find an exact quote about the 6 gun wing demanded by the Brits causing a production dlay but I will keep looking. The fact remains than in the summer of 1942 there was a shortage of Wildcats in the USN. Who would have thought it?

 

[Freebird]

"Upon seeing the installation which Grumman cooked up for 6 guns, this Section as well as Armament has realised we made a mistake, but there again it is too late to tamper with production at this time." A little later they did decide to tamper with production. "Armament labored to redesign the F4F4s folding wings to accomodate four guns instead of six and with 430 rounds each instead of 240. The resulting AC , which included a few minor changes tipped the scales about 500 lbs lighter than a standard f4f4." The Bureau did not tamper with Grumman's production but shocked Eastern on 14 June, 1942 by issuing a change order directing that the eleventh production FM1 and those following had to feature a redesigned 4 gun battery. Therefore I cannot find an exact quote about the 6 gun wing demanded by the Brits causing a production delay but I will keep looking. The fact remains than in the summer of 1942 there was a shortage of Wildcats in the USN. Who would have thought it?

Ren it seems like this refers to the time BEFORE Dec 1941, because the British order (folding wings, 6 guns) was presumably larger, the USN went along, then later (after Pearl) changed their mind, and ordered the 4 gun. But its not a surprise that their was a shortage of A/C in summer '42, because of the rapid expansion needed to convert from peacetime to wartime.

i will agree with you that the 4 gun model seems better, I think the British were looking at combat with Me 109's {in the Med} vs lighter Zeros with less protection.

It seems that it was a mistake by the Bureau to change production on an existing line so late in the game. The grumman line was working on the 6 gun model. The Bureau should have gone to Eastern right after Pearl {ie Jan 1942} and said THIS is the model that we want. Instead it seems that they were undecided as well {understandable with very little war experience} and it was only after the early battles in the S. Pacific that they decided that 4 guns would have been better. Again, it sounds as if this might be something that could only be learned through combat. IF they had decided right away after pearl what they wanted, there would have probably been no delays. However, the shortage of aircraft might not have been avoidable in any event.

 

[renrich]

I think that part of the problem was that the Wildcat, because of power available, was just not suitable to gain all the weight that the various mods caused. A big part of that weight gain was the 6 gun configuration. With all that extra weight the Wildcat just could not perform. I also know that the Brits had different training standards for their pilots(of necessity) than the USN and on average they did not have as much gunnery practise and were not trained for deflection shooting like the USN pilots. The Brits, FAA and RAF, were trained to get on the enemy's six, spray a bunch of bullets, their doctrine was they would have 2 seconds to fire and needed to put 261 303 bullets(as I recall) into a bomber to bring it down. That was the reason they wanted 8-303s in their fighters and I suspect they thought the 6-50s was needed in order to get the number of hits necessary. Our Navy pilots were not trained that way.

 

[renrich]

One interesting thing about the IJN fighter pilot tactics in 1942 is that I believe we all have images of Zeros engaged in turning fights with Wildcats. According to Lundstrom that was not true. Their tactics were to get an altitude advantage, make a firing pass and then climb out to do it again. In other words,pretty much energy tactics or what the flight sim people call boom and zoom. One reason for this was they did not want to engage in a WW1 type dogfight and risk being hit with no armor or SS tanks. Another reason was that they only carried 90 rounds per gun for the 20mms and the 7.7s had lots of ammo but weren't up to heavily damaging the robust US AC. The 20s also had a low muzzle velocity and they had to get close to get any hits. That is the reason the Thach Weave worked well as the A6M did not want to go head to head with a Wildcat. The Wildcat could reach out and touch the Zero with those 50s before the Wildcat was in good range of the 20 mms plus the Wildcat could take a lot more hits than a Zeke. However all the Wildcat tactics were defensive in nature. Just think you are in a F4F4 and you see a Zero. He can outclimb you, out turn you and out run you. You somehow get on his six and he loops and he is on your six. The only advantage you have is you can take more damage and live, you can maybe outdive him but if you can get him going real fast his ailerons get too heavy. Course he knows all that. What to do?