WI TBD-2.

[Riain]

I, for some perverse reason, like the TBD Devasator, or I don't hate and deride it like other people.

WI, knowing that war was looming and the TBF wouldn't be ready until early 1942 the USN ordered another batch of TBDs to be built in 1940/41. By then the R1830 made 11-1200 hp, which is a big boost from the original 900 hp. With this extra power the TBD could carry heavier defensive armament and have considerably better loaded performance. I don't envisage a huge order, perhaps 50-75 and cycling the 100 or so the USN already had back through the production line to get the enhancements.

So how would the early months of WW2 go if the USN had a more potent torpedo-bomber arm? Would better performance and heavier armament save TBDs from annihilation at Midway, even if they didn't get any hits? If the USN had 100 TBDs left after Midway (instead of OTL 39) would they keep them in service?

 

[Markus]

So how would the early months of WW2 go if the USN had a more potent torpedo-bomber arm? Would better performance and heavier armament save TBDs from annihilation at Midway, even if they didn't get any hits? If the USN had 100 TBDs left after Midway (instead of OTL 39) would they keep them in service?

1. Unlike the sub´s torpedoes, the arieal ones were sort-of OK.
2. The TBDs were actually tougher than the wikipedia article indicates. IIRC 7,7mm ammo was barely effective.
3. At Coral Sea the TBDs scored seven(!) hits on Shoho.

Now to your question:

On March 10th, 1942 104 planes from Lexington and Saratoga took part in the Lae-Salamaua Raid. 25 of them were TBDs, but only 13 were armed with torpedoes, the rest carried two 500lb bombs. That was done, because it was not clear if the TBDs could make it over the 7,500 feet high Owen Stanley Range while carrying a 2,000 pond "fish". The Japanese lost three transports -one to a torpedo armed TBD- and two more were damaged. so far the worst casualties the IJN had suffered.
Double the number of torpedo armed planes and the IJN might loose five to six transports.

At Midway, things look bad without a fighter even for "improved" TBDs. The "though" SBDs lost six out of 16 planes to nine attacking Zeros. The 15 TDBs were attacked by at least 21, maybe even 30 Zeros. A higher speed, more armour and a cal.50 gun for the rear gunner might help a bit, but if the plane is kept in service afterwards depends if the USN realizes the main casue for the losses was the lack of fighter protection.

 

[CalBear]

The TBD suffered from a range of issues, some inherent to the aircraft, some due to the weapon.

Weapon first - Mark 13 torpedo was slow (33.5 knots maximum speed vs 40 knots plus for it's British, Germany & Japanese counterparts) making it barely faster than the majority of the warships it was used against. It is noteworthy that Shoho, like most Japanese light carriers, was considerably slower (28.5 knots with a clean bottom) than the Akagi (31 knots) & Soryu (34 knots) fleet carriers that were present at Midway. This fragility would have forced even an improved Devestator to make attack runs at target sleeve speed.

The early war MK 13 also had the rather distressing habit of breaking up if launched at anything faster than a brisk walking pace (a slight exaggeration, but still...) or fail to start when entering the water, a trait demonstrated at Midway where several fish simply failed to initiate after being dropped, as well as the tendency to porpoise and/or surface run (several witness statements on the Japanese side state that CAP fighters actually managed to detonate torpedoes at Midway with their cowl machine guns, something that would only be possible if the torp was on the surface or very close to it).

By mid-1943 many of these problems were ironed out, and by mid 1944 the Mark 13 was arguably the best air launched torpedo of the war, but not in 1942.

The aircraft - The TBD was not just slow, it had a laundry list of issues, starting with the fact it was a 1935 design, making it seven years old in an era when aircraft had a shelf life of about two-three years (the same is true of the B5N, which also suffered horrific losses at both Coral Sea and Midway), The defensive armament of the aircraft was wholly inadequete (a single .30 MG for the gunnerand an additional .30 or .50 cal forward firing) and it's range when carrying a torpedo was pitiful. A more powerful engine would have helped slightly in the post attack breakaway phase of an action, but would also have further reduced the already poor range.

The TBD was, compared to the JNAF aircraft quite sturdy, almost invulnerable to the 7.7.mm machine guns of the A6M, as was common with all American designs. The Japanese learded fairly quickly, to their horror, that the only weapon that could be counted on to bring down the American planes was their 20mm cannon, which accessed a fairly small magazine (60 rounds per gun with the Type 99 Model One in use at Midway).

The U.S., had it been more aware of the war's fast approach, would have been far better served to have accellerated the TBF program (which was actually in service AT Midway, although in small numbers and flying from the Isalnd). Of course this is true of a rather awesome range of aircraft (P-38, P-47, F4U, just to name a few) and even surface ships (Essexes, North Carolina & Iowa BB's, etc.).

 

[Markus]

The U.S., had it been more aware of the war's fast approach, would have been far better served to have accellerated the TBF program (which was actually in service AT Midway, although in small numbers and flying from the Isalnd).

I disagree strongly. Rushing anything into service is usually a very bad idea.
Furthermore, after a bit googling the range looks quite ok. 430 miles with twice the payload of an SBD carried externally is nothing to sneer at. Weren´t air strikes launched 150 to 200 miles a way from the target anyway?

 

[Redbeard]

I can follow you Riain in your crush on the TBD - I don't know why, but I just like it

Perhaps it started by a feeling of great unjustice being done to the TBD - no torpedobomber in service in WWII would, have fared better in the same battle conditions. What the gallant USN pilots needed at Midway was not a better torpedobomber, but a strong fightercover.

Anyway a stronger engine being transformed into higher speed would only be of rekevance if a torpedo capable of higher speed dropping was introduced.

The best idea I can come up with would be utilising extra horsepower for strong armourprotection on the upper surfaces and around the crew. It would not be difficult to achieve immunity vs. 7,7mm, but the 20mm wing cannons on the Zero is another matter. The Japanese 20mm OTOH wasn't very powerful (and inaccurate too).

Regards

Steffen Redbeard

 

[The Dean]

I can follow you Riain in your crush on the TBD - I don't know why, but I just like it

Perhaps it started by a feeling of great unjustice being done to the TBD - no torpedobomber in service in WWII would, have fared better in the same battle conditions. What the gallant USN pilots needed at Midway was not a better torpedobomber, but a strong fightercover.

Exactly, look at the results the Fleet Air Arm achieved with the Swordfish! A far less likely looking aircraft than the TBD but nevertheless it did get the job done. However against enemy fighters it had no chance.

 

[CalBear]

I can follow you Riain in your crush on the TBD - I don't know why, but I just like it

Perhaps it started by a feeling of great unjustice being done to the TBD - no torpedobomber in service in WWII would, have fared better in the same battle conditions. What the gallant USN pilots needed at Midway was not a better torpedobomber, but a strong fightercover.

Anyway a stronger engine being transformed into higher speed would only be of rekevance if a torpedo capable of higher speed dropping was introduced.

The best idea I can come up with would be utilising extra horsepower for strong armourprotection on the upper surfaces and around the crew. It would not be difficult to achieve immunity vs. 7,7mm, but the 20mm wing cannons on the Zero is another matter. The Japanese 20mm OTOH wasn't very powerful (and inaccurate too).

Regards

Steffen Redbeard

It is true that there was not any torpedo aircraft that could have prospered under the conditions that confronted the pilots of VT-3, VT-6, and particularly, VT-8, (as was proved by the slaughter of the TBF squadron operating from Midway on the same June 4 morning) but the concept of a TBD II, is, IMO, not a justifiable expense.

IOTL the TBF missed being deployed on all the carriers at Midway by less than six months. (One of the curious little ironies of the war is that Grumman actually performed the Ribbon cutting ceremony on its Plant Two, where the TBF was to be built, and where the aircraft was introduced to the media, on December 7, 1941. Tell me God lacks a sense of humor.) The aircraft was already good to go for large scale production at this point, all that had prevented it reaching the fleet before even Coral Sea was that the ordering process was slower than necessary (or would be in more urgent circumstances) making the opening of the new Plant occur later in 1941.

To spend a large amount of funding on earrings for a plow horse would not have made any sense when you had a thoroughbred ready to run.

 

[Riain]

With an extra 300hp it would be able to fly much faster loaded with the torp, so would the Midway TBDs have even lost contact with the rest of the airgroup?

Even if they still did they would be subject to attack for considerably less time due to their higher approach speed. There might be 5 or 10 minutes less time for the Zeros to attack them before they killed their speed for the torp drops. (How long does it take 30 zeros to intercept and shoot down 3 TBD sqns, it wouldn't be a 1 minute job I assume?) And if the TBDs had .50cals for their rear gunners the Zeros would have even a tougher time shooting down all the TBDs.

As for the TBF, well it's an easy plane to love so where's the challenge in that? However there were only 6 TBFs at Midway, far outnumbered by the old TBD, and it took several months before enough were produced to outnumber the TBD. What did the USN use for a TB between the TBD retirement after Midway and the time when enough of TBFs were produced to sustain frontline operations?

 

[Markus]

To spend a large amount of funding on earrings for a plow horse would not have made any sense when you had a thoroughbred ready to run.

Better say; if you had a thoroughbred ready to run!
The development of the TBF began in April 40 and usually it took well over two years to get from the drawing board to mass production. So the USN ordering a limited number of "improved" TBDs in late 39/early 40 makes sense. This way you keep the production line open and have a "safety net" in case the new planes are delayed or the war is early.

@Riain: You sort-of got a point. New planes are needed in sufficient numbers, but according to wikipedia the USN had them in time before the next major naval battle after Midway.

 

[Matt Wiser]

The type of rear gun makes no difference; The TBDs were slaughtered at Midway for the following reasons:

1) Lack of fighter protection. VT-3 was the only squadron that had any fighters at all, but Jimmy Thach could only go with 6 Wildcats from VF-3, as the rest of the squadron was held back for CAP.

2) Ancient (by 1942 standards) design. In 1937, when the TBD was introduced to the Fleet, it could take care of itself if intercepted, as the JNAF's shipboard fighter was the A5M Claude, with only two 7.7 machine guns. Sticking a better engine on a TBD really doesn't make sense, especially if either the TBF or TBU (produced by Consolidated as the TBY-2 Seawolf) is coming by Spring of '42.

3) Wretched torpedoes. All four carriers at Midway could outrun the Mark-13 torpedo. Their running performance was shoddy, and whoever approved the weapon for Fleet service should have been hanged from the nearest yardarm. The same comment should go for those who approved the Mark-14 for subs, and the Mark-15 for surface ships. It took time, convicing bureaucrats the fish had problems, more realistic testing, and blood that shouldn't have been spilled before the Bureau of Ordnance (with fire-breathing Admrial King breathing down their necks) admitted there were problems and began to implement fixes. Admrial Charles Lockwood, who commanded SUBPAC from 1943-45, told his counterpart in SWPAC, "I doubt anyone will ever get a court-martial out of this fiasco." He was correct.

VT-8 had trained on the TBF before deploying with TBDs to the Pacific. The reason they kept TBDs was that there were problems with the Avengers' wing fold mechanisms, and that required a factory-level fix. Enough TBFs had arrived in Hawaii to reequip VT-8, but the carrier Hornet sailed on 29 May 42 for Midway before the transition could take place. 6 aircraft did fly to Midway, following a PBY as navigational lead, and only one made it back after striking Kido Butai on 4 June. That pilot won two Navy Crosses-one for the attack, and one for getting his shot-up plane back to the island. He wasn't hurt, but his radioman was wounded and the turret gunner was KIA.

 

[Riain]

Even in 1942 when compared to the Fairey Albacore the TBD is a modern plane.

With more defensive armament, more armour and better loaded performance the Zeros may not have shot down quite so many TBDs, despite the lack of fighter protection. The fact that fighters had become more lethal by 1939 is a good reason to authorise another run of TBD-2 with the armour, .50cals and better performance to better cope with these fighters.

I wonder what would have happened if VT8's 6 Avengers had been on the Hornet for the battle? However I do wonder how serious the navy was about putting these Avengers on the Hornet since they could only deploy 6 of them to the OA. Enough for an emergency but not to affect a wholesale conversion from the TBD.

 

[Matt Wiser]

Wouldn't have made any difference: TF 16 had to be off Midway by 1 June, as the attack was initally expected on 3 June, so Hornet and Enterprise had to sail on 28 May 42, regardless. VT-8 had aircrew ashore in Hawaii at NAS Ford Island, preparing for the transition, and 6 volunteer crews from the det flew to Midway. There were enough TBFs for VT-8 to transition, but the need to deploy prevented the transition from going fully ahead.

The main problem in 1939 for any TBD-2 variant is a still-isolationist and somewhat penny-pinching Congress. Even if the Navy wanted a new variant of the TBD, which they didn't IRL, Congress would still have to appropriate the money. Not to mention the likely opponent in 1939 from the Japanese was the A5M Claude, which the TBD-1 would have had a better time of it, but when the Zero came along, nothing short of cast-iron fighter cover would have protected any TBD squadron at Midway, which they didn't have. VT-8 actually did have the twin .30s as used in SBDs, and some homemade armor, but only VF-8 would have ensured that some Devastators survived to make runs on Kido Butai, and the ten F4Fs escorting VB-8 and VS-8 wound up ditching SE of Midway after they got lost returning to the carrier.The Navy's main strike priority in 1939-40 was the SBD program, and for fighters, both the F2A Buffalo and the F4F. And we all know how the Buffalo turned out....

The TBF or TBU/Y (if it had made it to the war zone) would still need escort on any opposed strike, period. The slaughter at Midway showed that most graphically. The bottom line is that the TBD had seen better days, and the sooner the TBF (or the TBY) arrived in Fleet VT squadrons, the better.

 

[Markus]

1. The Mk.13 torpedo was quite ok, if dropped at the right speed and altitude. The speed was low, but one attacks ships form ahead anyway.

2. I just realized: Had the TBD Devasator still been in production in 1940 it would have cahnged the whole war in the Pacific. The reason is the CAC Wirraway. It´s esentially a pimped T-6 Texan. It was a good general purpose aircraft. It did liason and recon and was even usefull for night harassment attacks, but it was used as a fighter, too. A plane that makes barely 200mph, has an anemic 600hp engine and two cal.30 peashooters used as a fighter you say.

IMO it´s a sure sign Australia and New Zealand were desperately short of warplanes and would have bought anything on the market ... like an improved TBD. And a couple of squadrons equipped with decent torpedo bombers would have been a hell of a speedbumb for the Japanese. In spite of Japanese air superiority allied bombers usually got through to the ships, but didn´t do much damage. The horizontal bombers(Blenheim,Hudson, B-10) hardly scored hits and one light bomb won´t sink a merchant ship. But one torpedo ... that´s something diferent.

 

[Matt Wiser]

Markus, the Mark-13's reliability issues weren't fixed until late 1943-early '44. The issues were: poorly designed contact fuse, lack of speed (most IJN warships could outrun the early versions), and drop height and drop speed. By late '43 and into '44, those issues had been corrected, but at a price paid for in blood by both TBD and TBF/M crews. I've read of some suggestions that the USN should have purchased the RN's 18-inch torpedo used on the Swordfish and Albacore, with modified lugs to fit the Avenger's bomb racks in the weapons bay. This was a much more reliable weapon, and certainly the best Allied air-dropped torpedo. The JNAF, with its Type 91 family, certainly had the best one of all. Why wasn't the RN torpedo purchased? Admrial Earnest J. King was a notorious Anglophobe. 'Nuff said there.

 

[CalBear]

Markus, the Mark-13's reliability issues weren't fixed until late 1943-early '44. The issues were: poorly designed contact fuse, lack of speed (most IJN warships could outrun the early versions), and drop height and drop speed. By late '43 and into '44, those issues had been corrected, but at a price paid for in blood by both TBD and TBF/M crews. I've read of some suggestions that the USN should have purchased the RN's 18-inch torpedo used on the Swordfish and Albacore, with modified lugs to fit the Avenger's bomb racks in the weapons bay. This was a much more reliable weapon, and certainly the best Allied air-dropped torpedo. The JNAF, with its Type 91 family, certainly had the best one of all. Why wasn't the RN torpedo purchased? Admrial Earnest J. King was a notorious Anglophobe. 'Nuff said there.

The MK 13 was an interesting design. It was overly fragile, something that was corrected (to the point that there wasn't a carrier launched aircraft that was capable of getting outside of it's drop envelope that could carry a torpedo until 1956, and even that is somewhat questionable) by late 1943 and it was a weapon that the U.S. kept in active inventory until 1950.

The British MK XII was not substantively better than the 1942 MK 13, it had a vey limited drop window (under 100 ft, 150 MPH) that was not much different than the American weapon. It was, depending on setting, from 4-9 knots faster than the U.S. fish, although this is less of an advantage as it initially appears since they were rarely, if ever, dropped in a stern chase mode. It should be noted that even the excellent IJN Model 21 was fairly easy to avoid if a fast ship was the target (witness the Yorktown at Coral Sea as one of numerous examples).

At the same time, the MK 13 had a unique advantage, albeit one that was not, AFAIK, used during the war. It's range was close to double that of the MK XII and very close to triple that of the Japanese Model 21 or German F5 (which was also a knot slower than the MK 13).

The MK 13 was designed to kill battleships, which topped out at 21-26 knots, from far enough out that the aircraft had a reasonable chance of survival. Unfortunately, it was 1944 before it was used in that mode, where it was remarkably effective (both Yamato class ships were killed by it). It's limitations in the early war years were serious, although no more serious than its peers.

 

[Markus]

(most IJN warships could outrun the early versions), and drop height and drop speed.

Moot points: You attack warships from ahead, merchant ships make usually less than 15 kts and a torpedo armed TBD isn´t faster than 100mph anyway.

By the way, my sources contradict the info of the poor contact fuse. They say that was a problem of the Mk.14. The Mk.13´s fuse was described as reliable due to the fish´s lower speed.