Making sense of USN WWII dive/torpedo bomber projects

[Colonial-Marine]

I've been trying to understand he USN's various dive and torpedo bomber projects following the TBF/TBM Avenger and SB2C Helldiver. Ultimately these efforts led to the AM Mauler and AD Skyraider but there was a large number of designs prior to this. Would categorizing these aircraft into three distinct efforts be accurate?

1941 requirements dive bomber:

Douglas SB2D - two-seat dive bomber to replace the troubled Curtiss SB2C Helldiver - 2 prototype XSB2D-1 built - change in requirements resulted in production order being switched to the single-seat BTD
Curtiss SB3C - two-seat SB2C Helldiver replacement - cancelled in favor of the Douglas SB2D before any prototypes completed
Douglas BTD "Destroyer" - redesign of the SB2D after revised 1943 requirements for a single-seat aircraft - 26 production BTD-1 and 2 prototype XBTD-2 with mixed propulsion built - production cancelled in favor of newer designs with superior performance

long range torpedo bomber (1942-43):

Grumman TB2F - large two engine long range torpedo bomber - determined to be too large for practical carrier operations - cancelled before prototypes built
Grumman TSF - two engine long range torpedo scout, derived from the F7F Tigercat - cancelled before prototypes built
Douglas TB2D "Skypirate" - large single engine long range torpedo bomber - 2 prototype XTB2D-1 built - no production order followed
Grumman TB3F - mixed power long range torpedo bomber - 3 prototype XTB3F-1 built - turbojet deleted and redesigned into ASW aircraft with 2 prototypes converted into separate "Hunter" and "Killer" variants - redesignated and saw service as AF "Guardian"

1943 requirements torpedo/dive bomber:

Douglas BT2D "Dauntless II" - single seat dive/torpedo bomber - redesignated and saw service as AD "Skyraider"
Martin BTM - single seat dive/torpedo bomber - redesignated and saw service as AM "Mauler"
Curtiss BTC - single seat dive/torpedo bomber - 2 prototype XBTC-2 built - rejected in favor of Douglas and Martin designs
Curtiss BT2C - less ambitious dive/torpedo bomber reusing many of components of the SB2C Helldiver - second crewman in rear fuselage as a dedicated radar operator - USN ordered prototypes late January 1945 - 9 prototype XBT2C-1 built
Kaiser-Fleetwings BTK - smaller single seat dive/torpedo bomber intended for escort carriers - 5 prototype/pre-production XBTK-1 completed

If we don't count redesigns, this was 11 different designs ordered by the Navy, 8 of which made it to prototype phase, 3 of which entered full scale production and had post-war service careers.

Other relevant aircraft:

Boeing F8B - designed as a fighter but Boeing emphasized its ability to perform other roles including dive and torpedo bombing - 3 prototype XF8B-1 built
Curtiss A-40 - the USAAF expressed interest in a de-navalized variant of the BTC and this was assigned the A-40 designation - not proceeded with
Vought TBU and Consolidated TBY "Sea Wolf" - a competitor with the Grumman TBF Avenger for the torpedo bomber role - Vought lacked the manufacturing capacity, so the project was transferred to Consolidated - production did not begin until August 1944 with 180 production TBY-2 completed - all further orders cancelled with the end of the war

 

[isayyo2]

Does Boeing's XF8B fit into this list?

 

[Colonial-Marine]

Does Boeing's XF8B fit into this list?

I think the Boeing XF8B came about more due a separate requirement the Navy developed with Boeing. I'm not sure how interested they were in using it as a dive or torpedo bomber but the ability to serve as a general-purpose fighter bomber (a role the F4U Corsair was proving the effectiveness of) had to be a good selling point. It's a shame the Navy didn't go forward with the XF8B but they must have viewed it as a fighter first and foremost and when it came to fighters jet engines were the future.

 

[isayyo2]

@Colonial-Marine
Thanks for the insight!

 

[robunos]

Regarding the Boeing XF8B-1, see HERE . . .

cheers,
Robin.

 

[Colonial-Marine]

Regarding the Boeing XF8B-1, see HERE . . .

cheers,
Robin.

Excellent article. I had thought it was viewed a bit more favorably in testing but I guess there is no getting over the fact that it was very large and heavy for a single engine fighter. A real "jack of all trades master of none" I suppose.

 

[tallguy]

Where does the Vultee TBV (naval Vengeance )come into the mix?

 

[BlackBat242]

Where does the Vultee TBV (naval Vengeance )come into the mix?

Pre-war (1940) export dive bomber designed for France, who ordered 372 in early 1940. First flight 30 March 1941.

Deliveries cancelled by the fall of France, 200 ordered by UK in July 1940, 100 more in December - saw combat mostly in Burma/India - a total of some 900 total purchased (501 directly from Vultee, bypassing US military controls).

After 7 Dec. 1941 US Army Air Force held onto some 243 of the British order, then ordered some 920 of a "better" version more to its liking.

The RAAF then ordered 400. 58 were still to be delivered when production of the type ended in March 1944 (other sources say only 121 delivered).

The total built was 1,931 (as for many WW2 aircraft the total numbers for each customer do not necessarily reflect actual production numbers, as contracts were frequently altered).

A torpedo-bomber version was proposed, but none were built.
No Vengeances of any variety were produced for the USN - the aircraft was a land-based-only program.

 

[tallguy]

Pre-war (1940) export dive bomber designed for France, who ordered 372 in early 1940. First flight 30 March 1941.

Deliveries cancelled by the fall of France, 200 ordered by UK in July 1940, 100 more in December - saw combat mostly in Burma/India - a total of some 900 total purchased (501 directly from Vultee, bypassing US military controls).

After 7 Dec. 1941 US Army Air Force held onto some 243 of the British order, then ordered some 920 of a "better" version more to its liking.

The RAAF then ordered 400. 58 were still to be delivered when production of the type ended in March 1944 (other sources say only 121 delivered).

The total built was 1,931 (as for many WW2 aircraft the total numbers for each customer do not necessarily reflect actual production numbers, as contracts were frequently altered).

A torpedo-bomber version was proposed, but none were built.
No Vengeances of any variety were produced for the USN - the aircraft was a land-based-only program.

Then why was the TBV designation applied? Lend Lease?

 

[BlackBat242]

Then why was the TBV designation applied? Lend Lease?

The only mention I can find for "TBV" is for the proposed and un-built torpedo-bomber version (TBV-1).

Vultee used the designation V-72 ( Vultee Model 72) for the French order, the UK used Vengeance I, Vengeance II, etc for theirs - and the US Army used A-31 & A-35 for theirs.

 

[P-STICKNEY]

Then why was the TBV designation applied? Lend Lease?

Could you perhaps be confusing it with the Vought TBU / Consolidated TBY?
Basically an R2800 powered competitor to the TBF, designed and prototyped by Vought, but priority put it on the back burner, so development was slow. Vought was going all out on Corsair production, so TBU production was transferred to Consolidated. (Hence the TBY) By the time production got going, all deployed Torpedo Bombers were Avengers, the Multi-Seat Torpedo and Dive Bombers were going to be replaced by Single Seat Attack Aircraft, so they never reached front-line units.

 

[P-STICKNEY]

I've been trying to understand he USN's various dive and torpedo bomber projects following the TBF/TMB Avenger and SB2C Helldiver. Ultimately these efforts led to the AM Mauler and AD Skyraider but there was a large number of designs prior to this. Would categorizing these aircraft into three distinct efforts be accurate?

1941 requirements dive bomber:

Douglas XSB2D - two seat dive bomber designed to succeed the troublesome SB2C Helldiver, two built
Curtiss XSB3C - cancelled in favor of the XSB2D before any prototypes built
Douglas BTD Destroyer - redesign of the XSB2D after revised 1943 requirements for a single seat aircraft, some sources claim it had worse performance, 26 built, further production cancelled in favor of newer designs

long range torpedo bomber (1943):

Grumman XTB2F - large two engine long range torpedo bomber, cancelled before prototype built
Grumman XTSF - two engine long range torpedo scout, derived from the F7F Tigercat, cancelled before prototype built
Douglas XTB2D Skypirate - large single engine long range torpedo bomber, cancelled after two prototypes
Grumman XTB3F - mixed power long range torpedo bomber
Grumman AF Guardian - redesign of the XTB3F into an anti-submarine aircraft, jet engine deleted

1943 requirement multi-role bomber:

Douglas XBT2D - single seat dive/torpedo bomber which became the AD Skyraider
Martin XBTM - single seat dive/torpedo bomber which became the AM Mauler
Curtiss XBTC - single seat dive/torpedo bomber rejected in favor of the Douglas and Martin designs, two prototypes built
Curtiss XBT2C - less ambitious dive/torpedo bomber reusing a large number of components of the SB2C Helldiver, second crewman in rear fuselage as a dedicated radar operator, nine built
Kaiser-Fleetwings XBTK - smaller single seat dive/torpedo bomber intended for escort carriers, cancelled after five prototypes

So a total of 11 different designs ordered by the Navy, 8 of which made it to prototype status, 3 of which saw service post-war.

I'd say that what you're seeing is the result of Combat Experience outpacing development. The 1941 Specs are calling for more of the Prewar concepts, but bigger and faster, but not fast enough. By 1943, combat experience showed that fighter escort was a better defense than gunners with limited arcs of fire.

 

[tallguy]

Could you perhaps be confusing it with the Vought TBU / Consolidated TBY?
Basically an R2800 powered competitor to the TBF, designed and prototyped by Vought, but priority put it on the back burner, so development was slow. Vought was going all out on Corsair production, so TBU production was transferred to Consolidated. (Hence the TBY) By the time production got going, all deployed Torpedo Bombers were Avengers, the Multi-Seat Torpedo and Dive Bombers were going to be replaced by Single Seat Attack Aircraft, so they never reached front-line units.

Thanks, but no. The TBY and the TBV are different beasts.

 

[Stargazer]

1943 requirement multi-role bomber:

Douglas XBT2D - single seat dive/torpedo bomber which became the AD Skyraider
Martin XBTM - single seat dive/torpedo bomber which became the AM Mauler
Curtiss XBTC - single seat dive/torpedo bomber rejected in favor of the Douglas and Martin designs, two prototypes built
Curtiss XBT2C - less ambitious dive/torpedo bomber reusing a large number of components of the SB2C Helldiver, second crewman in rear fuselage as a dedicated radar operator, nine built
Kaiser-Fleetwings XBTK - smaller single seat dive/torpedo bomber intended for escort carriers, cancelled after five prototypes

Not to undermine your work in any way, but despite the fact that it can sometimes be found on the web, it is incorrect to write the designations the way you did.

The way the US Navy system worked, the basic model designations were always BT2D, BTM, BTC, BT2C, BTK.
The first versions of each were designated BT2D-1, BTM-1, BTC-1, BT2C-1 and BT2D-1.
If it so happened that the first version (or in fact, any later version) had a prototype, or was a prototype, the X was added to it, but the logic was always that the XBTC-1 was a particular variant of the BTC-1, itself a version of the BTC.
I could develop further with other examples, but I'm sure you get the jist of it.

Consequently, "XBT2D" and the others do not correspond to anything as such and are simply in error.

Also, according to my files, there was a Douglas BTD project, which would have been a modified SB2D.

 

[Colonial-Marine]

Thanks for the

Not to undermine your work in any way, but despite the fact that it can sometimes be found on the web, it is incorrect to write the designations the way you did.

The way the US Navy system worked, the basic model designations were always BT2D, BTM, BTC, BT2C, BTK.
The first versions of each were designated BT2D-1, BTM-1, BTC-1, BT2C-1 and BT2D-1.
If it so happened that the first version (or in fact, any later version) had a prototype, or was a prototype, the X was added to it, but the logic was always that the XBTC-1 was a particular variant of the BTC-1, itself a version of the BTC.
I could develop further with other examples, but I'm sure you get the jist of it.

Consequently, "XBT2D" and the others do not correspond to anything as such and are simply in error.

Also, according to my files, there was a Douglas BTD project, which would have been a modified SB2D.

Thank you for the clarifications, I'll edit my post with those corrections.

The BTD was indeed the single-seat redesign of the SB2D. I'm a bit skeptical of the claim that it had worse performance than its two-seat predecessor. Removing the gunner, turrets, and associated systems allowed them to add more armor and fuel but it would have taken a whole lot of both to notably reduce performance. Douglas' work on the more capable BT2D (which became the famous AD Skyraider) was progressing well however, so it definitely made sense to cancel BTD production when they did.

If the Navy hadn't changed requirements and went ahead with the original two-seat SB2D I wonder if by 1944 the US Navy could have had a better alternative to Curtiss' troublesome SB2C Helldiver.

 

[1635yankee]

I think a large source of the confusion of which you speak is the USN's changing requirements, which were do to increasingly serious analysis of aircraft and aircrew combat performance during WW2. I think these were 1) the USN found aircraft gunners had negligible effects on aircraft survival, at least with carrier-launched aircraft and 2) improving technology eliminated the need for a second crewman for navigation and radio duties, even during night operations.

 

[Oleo]

I have a brochure somewhere for a large Grumman twin engined carrier strike aircraft ....probably XTB2F....It looks very like a Tracker but more streamlined and with a lot more power. Not had it out in years, I think it just had a G-number designation ...the artists impressions showed it in overall glossy sea blue so quite late war.

 

[Jemiba]

Maybe this one ?

(Design 55) Grumman XTB2F-1