Dive vs Torpedo Bomber

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An advantage that FAA Torpedo-divebombers had was that they could use a divebomb attack profile while torpedo bombing, so they could attack targets even in confined waters, where there was at least a few hundred yards of open water in front of the target, as they could dive vertically with the torpedo to avoid the terrain.
 

Hi

Just after dawn on 6th April 1941 a Beaufort of No. 22 Sqn. flown by Flying Officer K Campbell and crew made a low level torpedo attack against the Gneisenau in the heavily defended Brest harbour, putting a 40 feet hole in the ships side. The aircraft was shot down and crew killed, Campbell being awarded the VC. Ironically the ship had just been moved out of dry dock due to an unexploded 250 lb SAP bomb being near by. I don't think Brest harbour was very big or deep.

Mike
 
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If you have a limited CAG size, a dive bomber that can also carry a torpedo is better than a torpedo bomber that cannot dive bomb. Look at wing wing carriers today, where CAGs are made up of a single fixed wing type.
 
If you have a limited CAG size, a dive bomber that can also carry a torpedo is better than a torpedo bomber that cannot dive bomb.
They had to wait until they got powerful enough engines to allow one plane to do both.
The TBD Devastator used a 422 sq ft wing, The Northrop BT-1 (which was modified into the SBD) used a 322 sq ft, both used the same engine.

I would also note that, torpedoes being expensive, the requirement that lead to the Avenger required the plane to land back aboard the Carrier still carrying the torpedo and do so with a stalling speed of 70mph. A reason for it's 490 sq ft wing.

Most torpedo bombers were expected to have similar strike radius as the dive bombers but were carrying a heavier payload, for the Americans it could be twice as much (or even four times as much).
SB2Cs didn't start really carrying torpedoes until they got 1900hp engines and a quick change torpedo mount.
 


I'm not sure what the conclusion is (or if it was just a nice history lesson).

It could very reasonably be that torpedos were a better choice in 1920, even if dive bombers were the better choice in 1940.

In fact, the Swordfish could and did do both. I understand that they were more often torpedo bombers, but that might be FAA making their best decision given limited information, or it might be that the Swordfish isn't the world's best dive bomber and that was the airplane they had.
 


This makes ZERO sense to me.

Torpedo bombers existed throughout the war. Given one had a torpedo bomber capable of meeting torpedo bomber requirements, one could put dive brakes on it, bombs in it, and have a dive bomber.

(or just use a biplane with wire braced wings, and not worry about speed brakes
 

The airframe has to be stressed for divebombing, and that always adds considerable weight. The FAA used biplane torpedo-divebombers because they had the wing area for STOL whilst lifting large loads with low powered engines, but the airframe still had to have the strength to fly a dive-bomber attack profile.

The TBF/TBM was only stressed for ~3g at max TO weight where the SBD and SB2C were stressed for ~7G.
 

That does make more sense.
 

That the Air Ministry/RAF was not interested in torpedo aircraft. I made another reply further down. The raison d'etre of the RAF as an independent air force in the inter-war years was as a strategic bombing force and deterrent. Attacking ships with torpedoes was considered 'unsuitable employment' for aircraft.

It's why Coastal Command's striking force in 1939 and early 1940 consisted of two squadrons of these (though just 12 aircraft, less than one squadron, were operational at the outbreak of the war as the remaining aircraft were being overhauled).



The Vickers Vildebeest. It was not even originally specified as a torpedo aircraft but built to a 1926 specification for a 'light' bomber, which explains its exceedingly limited range.
 
They had to wait until they got powerful enough engines to allow one plane to do both.
The TBD Devastator used a 422 sq ft wing, The Northrop BT-1 (which was modified into the SBD) used a 322 sq ft, both used the same engine.
This makes ZERO sense to me.
In order to lift the heavy torpedo, and to fly safely(?) at torpedo launch speeds on the same HP, the TBD had to (as Shortround said) have a much larger AND THICKER wing making it slower and more vulnerable when in harm's way. And due to its G limits, it couldn't maneuver as aggressively in its own defense, even when unladen. Their fuel efficient cruise speed was so much lower than other strike aircraft, that ideally they would be launched first if part of a combined strike and be overtaken enroute by the rest.
Cheers,
Wes
 
Designing and effective dive bomber wasn't quite as easy as it seems. The aircraft is the delivery system, the actual weapon is the bomb or torpedo (or bullets/shells).

I don't have information about the early US AP bombs but the 1000lb MK 33 that was introduced in october of 1942 was rated at piercing 5 in of deck armor if dropped from 10,000ft OR from 6,500ft in a 300kt 60 degree dive.

The slower the dive the higher the release point has to be to get the same armor penetration. The higher the release point the less accuracy and the more time for the ship to evade.

Ships with thinner decks can be attacked from lower altitudes and HE bombs don't need/use the impact speed for target effect. SAP bombs do need a certain impact velocity to penetrate light armor.

A lot of planes could "dive bomb" but if you are planning on attacking large ships with thick decks using a Biplane even with an AP bomb may not be the way to go.

Not to mention low, slow aircraft are an AA gunners dream.
 

The "Roadsteads" of Brest Harbour are huge - The harbour where the Gneisenau was is only separated from it by a low mole - Hence it presented no problem for the run-in of the Beaufort and could not be deemed "confined". - Where Campbell and his crew were amazingly brave was that that mole was lined with AA guns. There is a nice map on this website...

Coastal Command Bombers Against the German Navy II
 
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The Mk 33 and Mk 1 (1600 lb) AP bombs did not work as advertised and were a major disappointment to the USN BuOrd which designed and manufactured them. The much improved Mark 13 torpedo of 1944 became the preferred weapon for attacking armored ships. I have noted in a previous post that the RN used the Mk 1 to attack the Tirpitz without success. From the








As for the early war AP bombs, primitive is the best way to describe them. They were pre WWI technology as can be seen by the "pillbox" armor piecing cap on the M61



The M61 was converted from a projectile for a deck piercing mortar first produced in 1890. Here is a mesmerizing video of a battery of these mortars in operation.

 
The bombs may not have worked as advertised, but they do point out the need for different airplanes in the 30s and early war years, A torpedo bomber with dive brakes added on was unlikely to dive fast enough or pull out late enough to actually be a good dive bomber even if it could dive steeply or had clearance to drop a bomb in a 60 degree or better dive.

There were a number of requirements for aircraft that seldom make into the short stories or articles about them that had quite a bit to do with the actual design choices. Landing speeds and take-off runs and desired ranges had quite an impact.
 

Dive brakes limited the speeds of most divebombers up to the SBD-3 (including the Albacore) to between 200 and ~250 knots. A divebomber achieving 300 knots in a low altitude release would be exceptional, IIRC.

The Barracudas attacking Tirpitz released their 1600lb bombs at up to 65degs
 
Dive brakes limited the speeds of most divebombers up to the SBD-3 (including the Albacore) to between 200 and ~250 knots. A divebomber achieving 300 knots in a low altitude release would be exceptional, IIRC.

The Ju 87 was certified to carry out dives up to 'stress group 5' which required a maximum safe diving speed of 600 Km/h (about 373mph). The dive brakes were required to slow the aircraft down to give the pilot time to properly aim at his target and to reduce the forces during the pull out.
I have no idea what the maximum safe dive speeds were for Allied types, but I doubt they were anything like that.
 

This site, Pearl Harbor Douglas SBD Dauntless Scout / Dive Bomber shows the nominal attack profile of an SBD; doing a little math gives a speed of 300 mph during the pullout. I remember seeing that the SBD was stressed for at least 7 g; nominally, this would permit about 400 mph. See also How fast do dive bombers dive?

Note that there is another limit, never-exceed speed, Vne, which can be set by flutter or other constraints, not g limits.
 
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I have seen a photo of the Beaufort wreckage being lifted out of the harbour. What was striking was the body of the pilot was still upright in his seat, looking almost untouched, it was very clear as the impact on the water had stripped away the nose of the aircraft. It's one of those pictures that you never forget.
 
To have kept on going when the rest of the other attacking aircraft had all turned back because of the lousy weather was amazing bravery.
 

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