The Doolittle Raid....

[XBe02Drvr]

In order to drive a Casablanca class CVE 28kn, you need >50,000 hp and to run the engine in excess of 350 rpms. Didn't happen

Well you can take that up with James Hornfischer, author of "Last Stand of the Tin Can Sailors", If he's in error on this point, it wouldn't be the.only detail error he's guilty of.

 

[Greyman]

Interestingly, British-operated Mitchells retained those under-turrets.

Just as an interim measure. They judged the Bendix 'K' unsatisfactory and these were replaced with FN.64 turrets 'at the earliest possible date'.

That said -- whenever I come across a photo of an RAF Mitchell more often they seem to have the Bendix vs. the Frazer-Nash ...

 

[soulezoo]

Can we put a CVE and/or DE hitting 28+ kn into the myths busted section of the forum?

The Casablanca class CVEs at Samar had a designed top speed of 19 kn on 9,000 hp from a 5 cylinder Skinner Marine uniflow steam engine operating on steam of 285psi and 577°F. The best I can find is the engines ran round 200-225 rpms.

In order to drive a Casablanca class CVE 28kn, you need >50,000 hp and to run the engine in excess of 350 rpms. Didn't happen - the reciprocating engines wouldn't run that fast, the boilers would develop that much steam. And ships take time to accelerate, so you need more than just a couple minutes - see HMS Glorious.

Even the USS Samuel B. Roberts didn't hit 28+ knots for similar reasons: The DE was designed for 24 kn on 12,000hp. To hit 28.7 kn (speed noted on Wiki), the boilers would need to be producing enough steam for almost 50,000 hp. Sticking a screwdriver in the relief valve and letting pressure go to 50% overload isn't changing the underlying thermodynamics that there wasn't enough steam flow.

I know little of these CVE's, so this post is not of a declared personal knowledge, neither did I stay at a Holiday Inn Express last night.
I was watching a History Channel show of the event with the Samuel B Roberts and Johnston (along with the others), and a statement was made by the narrator, and repeated by one of the surviving combatants (I don't remember if he was a survivor from the Johnston or the Roberts, both were recounting their experience), was that the CVE's (like the St. Lo) could only do 16 knots. This was significant as the Japanese Task Force was doing approximately 26-28 knots coming at them. I recall this specifically as I was struck by the low speed of the CVE's. How could they get anywhere in a reasonable time frame?

 

[GrauGeist]

Just about all USN escort carriers were built on converted hull designs and thus were about the same speed as the merchant ships they were escorting.

The Long Island class were cargo ship hulls, good for about 16.5 knots.

The Bogue class were larger cargo ship hulls, good for about 18 knots.

The Sangamon class were built on oiler hulls, good for about 18 knots.

The Ruler class were purpose built CVEs from the hull up, good for 17 knots.

Commencement Bay class were purpose built CVEs (though based on a tanker hull design) and were good for 19 knots.

Casablanca class were also purpose built CVEs, good for 19 knots.

There were other, less numerous classes in service, but this gives an idea of what was out there.

 

[Maty12]

Because of the early launch, only one B-25 crossed the coast of Japan at its correct point. That was Plane No 10, commanded by Joyce and navigated by my High School Teacher, H. E. Crouch.

The standard B-25B weapons fit included a remote controlled belly turret with two .50 cal guns. Those were removed on the Doolittle B-25's to allow extra fuel as well as because experience showed showed you could not hit anything with the damn thing, anyway. Thus the need for the dummy guns sticking out the tail bubble. It is entirely possible, that given the lack of low six o clock protection, more than just the Doolittle B-25's stuck a couple of dummy guns out the tail bubble. I think one book mentioned some units employed a .30 cal gun mounted a Jeep spring sticking out the tail bubble, designed to be turned on remotely to scare off fighters attacking from the tail.

In fact, in the Med some B-25 units installed a tail gun position with two .50 cal guns that looked very much like the ones factory installed on the B-25H and B-25J, although a little cruder.

Another big reason that the belly turret was removed was that the raid's altitude was decided to be low level, so a belly turret was useless, as was the Norden sight. Removing the turret saved 600 lbs according to Lawson, but he does not mention how much weight the replacement of the Norden sight saved. Lawson also describes training at 500 ft before the altitude was raised to 1,500 ft, which left him quite relieved because a training run with 100 lbs bombs made him jump and hit his head on the plane's roof.

A few other nuggets from the book that y'all might find interesting:
The plan was never specifically 16 B-25s. 24 volunteer crews arrived in Eglin AFB, and those were the ones that were trained. During the course of training not all aircraft made the cut. Lawson does not give the date, but mentions that during short-field takeoff practice Lt. Joyce's aircraft dropped back down onto the runway after raising the gear, though fortunately there was no fire and no deaths. Joyce did still go on the raid, but that's one less B-25. Before being loaded onto the Hornet, all the aircraft had their propellers replace, radios removed and were given a few days in McClellan Field to have any other necessary repairs done. Lawson's opinion of these repairs is very negative, and he blames them for damage to the Ruptured Duck's interphone system. Arriving in Sacramento, Doolittle asked crews if everything was okay with their aircraft. Lawson said that the aircraft was okay, and the Duck was lifted onto the Hornet. He then saw other crews being instructed to taxi into a hangar instead and learned that those aircraft had been cut from the raid. Had he mentioned his interphone problems he would've been too. Two now ship-less crews went on the USS Hornet as replacements, and according to Lawson one pilot did choose to switch his copilot for one of the replacements before the raid.

And on another note, the reason the aircraft involved in the raid had deicer boots fitted was because at the time the USAAF was negotiating with Russia about letting the aircraft land there (which York and his crew ended up doing anyway due to being very low on fuel) and delivering them as lend-lease. While Russia ultimately decided against allowing the crews to land due to their neutrality pact with Japan and plans were made to land in China instead, the boots were never removed.

 

[MIflyer]

Another problem "The Ruptured Duck" had was that the turret would not power up unless the pilot turned on auxiliary power.

Many years after the war my HS teacher constructed a copy of the "protractor" sight used on the raid for display by the USAF Museum. During my USAF career one day I went into a building that had been named after Gen Doolittle and was stunned to see that they had that very sight on display in the lobby.

 

[Marshall_Stack]

Another big reason that the belly turret was removed was that the raid's altitude was decided to be low level, so a belly turret was useless, as was the Norden sight. Removing the turret saved 600 lbs according to Lawson, but he does not mention how much weight the replacement of the Norden sight saved. Lawson also describes training at 500 ft before the altitude was raised to 1,500 ft, which left him quite relieved because a training run with 100 lbs bombs made him jump and hit his head on the plane's roof.

A few other nuggets from the book that y'all might find interesting:
The plan was never specifically 16 B-25s. 24 volunteer crews arrived in Eglin AFB, and those were the ones that were trained. During the course of training not all aircraft made the cut. Lawson does not give the date, but mentions that during short-field takeoff practice Lt. Joyce's aircraft dropped back down onto the runway after raising the gear, though fortunately there was no fire and no deaths. Joyce did still go on the raid, but that's one less B-25. Before being loaded onto the Hornet, all the aircraft had their propellers replace, radios removed and were given a few days in McClellan Field to have any other necessary repairs done. Lawson's opinion of these repairs is very negative, and he blames them for damage to the Ruptured Duck's interphone system. Arriving in Sacramento, Doolittle asked crews if everything was okay with their aircraft. Lawson said that the aircraft was okay, and the Duck was lifted onto the Hornet. He then saw other crews being instructed to taxi into a hangar instead and learned that those aircraft had been cut from the raid. Had he mentioned his interphone problems he would've been too. Two now ship-less crews went on the USS Hornet as replacements, and according to Lawson one pilot did choose to switch his copilot for one of the replacements before the raid.

And on another note, the reason the aircraft involved in the raid had deicer boots fitted was because at the time the USAAF was negotiating with Russia about letting the aircraft land there (which York and his crew ended up doing anyway due to being very low on fuel) and delivering them as lend-lease. While Russia ultimately decided against allowing the crews to land due to their neutrality pact with Japan and plans were made to land in China instead, the boots were never removed.

So there was the possibility that 18 planes could have gone on the raid? There was enough room of the flight deck for that?

 

[GrauGeist]

So there was the possibility that 18 planes could have gone on the raid? There was enough room of the flight deck for that?

I beleive by the time they were ready to go, it had been decided on 15 for the mission, the 16th was for a takeoff test after they shipped out, but the demo was cancelled and the 16th was included in the raid.

 

[ODonovan]

I always wondered why they didn't do the raid with P-38s. The "F" model had just come out. It had a 2000 mile range with drop tanks. Clean, it could carry 2,000 lbs. of bombs, which is what each Mitchell carried on the raid. With its (somewhat) smaller size, they could've sent more than 16 Lightnings on the USS Hornet. With a mix of extra fuel and bombs, and the ability to send more aircraft, the Lightning has always seemed to me to have been the obvious choice for the mission.


-Irish

 

[wuzak]

No, the P38F was still months away.

 

[Thumpalumpacus]

I always wondered why they didn't do the raid with P-38s. The "F" model had just come out. It had a 2000 mile range with drop tanks. Clean, it could carry 2,000 lbs. of bombs, which is what each Mitchell carried on the raid. With its (somewhat) smaller size, they could've sent more than 16 Lightnings on the USS Hornet. With a mix of extra fuel and bombs, and the ability to send more aircraft, the Lightning has always seemed to me to have been the obvious choice for the mission.


-Irish

This was addressed above. B-25 pilots and crew had already been doing ASW patrols overwater for some time (crew experience). And what would the range for the -38s be carrying an extra ton of bombs and no extra fuel? How many P-38 pilots had experience with navigating long flights overwater at that time?

 

[FLYBOYJ]

P-38F production started in February 1942. Although capable, I doubt you would have had aircraft and trained aircrew ready by April.

 

[GrauGeist]

The P-38E had just been delivered to the 1st Pursuit Group in limited numbers, in October '41 - not enough time to get hours in, work out the bugs and be ready for such a mission by the first week of April.
The 24 hand picked B-25 crews had all been with the 17th BG since receiving their Mitchells back in early summer of '41 and had been conducting ASW patrols off the Atlantic coast - four months of experience by the time the 1st PG received their first P-38Es.

 

[FLYBOYJ]

And I doubt there was any short field testing done on the P-38 based on carrier operations

 

[nuuumannn]

Certainly there were not many Mosquito B.IVs at that time, and they would have been the series i, of which only 10 were made. The B.IV series ii would only become operational the following month.

Kind of a moot point whether or not the type was available; it doesn't change what I said, that the type was in service and it is highly unlikely, if not impossible that the US would have considered them.

 

[GrauGeist]

Let's consider for a moment, that the RAF made Mossies available to the USAAC.
Would there have been 24 available in fall of 1940?
The B-25 crews that worked up the mission between February and April were seasoned crews, so there would have been an extended time of familiarization needed prior to the work up period (which is why I figured fall).

 

[pbehn]

Let's consider for a moment, that the RAF made Mossies available to the USAAC.
Would there have been 24 available in fall of 1940?
The B-25 crews that worked up the mission between February and April were seasoned crews, so there would have been an extended time of familiarization needed prior to the work up period (which is why I figured fall).

It would be a bit controversial to use Mosquitos to declare war on Japan? (Typo I presume).

 

[GreenKnight121]

Another big reason that the belly turret was removed was that the raid's altitude was decided to be low level, so a belly turret was useless, as was the Norden sight. Removing the turret saved 600 lbs according to Lawson, but he does not mention how much weight the replacement of the Norden sight saved.

Removing the Norden sight had exactly nothing to do with weight reduction... it was a classified piece of equipment that we had not even let the British look at... and which worked best at high altutide. Given the low altitude of the raid, and the strong possibility of at least one being shot down in Japanese-held territory (which did, in actuality, happen), it was determined to be necessary to remove the sights (replacement ones were to be provided in China).

Also, isn't the Lexington and Saratoga bigger than the Hornet? Couldn't they have used one of them?

The two Lexington class carriers were slightly larger (60 feet longer, 12,000 tons heavier, half a knot faster, and 6 aircraft more powerful) than Hornet, but were not readily available at the time. Saratoga was in drydock and Lexington was prowling the Coral Sea protecting Port Moresby. Besides, Doolittle's planes were already embarked on Hornet, who had ferried them from Alameda, and transferring them to another carrier would have been impossible to do in the requisite secrecy.

Of the Yorktown class CVs, Hornet also had the longest (814' vs 802') and widest (114' vs 109'* flight deck.
Sara & Lex had a 866' x 106'** flight deck - Sara's was lengthened aft to 888' in 1941.



* Although all three were only 86' wide abreast the island, the added width was to accommodate a row of 20mm guns outboard of the island, where Yorktown & Enterprise stowed ship's boats - E had the boats removed and guns added in mid-1943, her new specs listed 114' flight deck width.

** 83' abreast the island.

 

[nuuumannn]

Would there have been 24 available in fall of 1940?

1940? Typo, Dave? By late 1941 production of B.IVs hadn't produced many examples. Certainly the type's performance was known by then, but in the timeframe it was not likely enough were built, unless the USAAC anticipated the raid prior to Japan attacking Pearl and pressure was made to prioritise production on the B.IV over the night fighter and PR examples. I think we are retrospectoscoping by considering the Mossie, but that's why we are here, I guess...

 

[MIflyer]

The B-25's were supposed to fly on to airfields in China and join our forces there. I doubt that Mossies or P-38's could have been supported logistically given those plans.