swampyankee
Chief Master Sergeant
- 4,036
- Jun 25, 2013
An interesting question. I can see one benefit to two types: easier training, as dive bombing and torpedo attack involve different skills.
Dive vs Torpedo Bomber
- Thread starter kitplane01
- Start date
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An interesting question. I can see one benefit to two types: easier training, as dive bombing and torpedo attack involve different skills.
The engine technology for a combined carrier operable monoplane TB/DB didn't exist until engines of 1600+ HP became available. Before these engines existed you could have monoplanes that were stressed for DBing, but had insufficient lifting capacity for a torpedo, or you could have monoplanes that had the wing area and lifting capacity to carry a torpedo, but to save weight, they could not be stressed for DBing.
The RN's FAA stuck with biplane designs for the Swordfish and Albacore because they could do both roles utilizing lower powered engines. When the USN sorted out the SB2C, with the -4 and later variants, the logic of having two distinct types faded and there were calls from within the USN to remove the TBF/TBM from USN fleet carriers.
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(my bold) Source for the bolded sentence?
The SBD-3 carried 1600 LB bomb on 1000 HP for take off. FAA torpedo weighted 1750 lbs, so perhaps it is too much to ask for a 60% power increase so one can lug extra 10% more.
Granted, the US torpedoes were a lot heavier at 2000+ lbs.
The first 1600HP+ engines didn't enter USN or FAA service until 1942.
The SBD3 had to reduce fuel to 158usg to carry a 1600lb bomb and no SBD variant ever flew a combat mission from a carrier with this weapon, according to the USN's aviation stats.
The SBD-5 was rated for a 95nm combat radius with the 1600lb bomb and 165usg fuel and it had a longer TO run than the -3 despite another 200hp on TO (which suggests that SBD-3 stats were optimistic). To make the SBD, or a similar aircraft, truly combat useful the combat radius would have to be ~200nm and then the fuel and weight requirements dictate a somewhat larger airframe. Additionally, the SBD is a bit of a misleading case because it doesn't have folding wings.
You have misunderstood me.
I was asking for a source that confirms without a doubt that one needs at least 1600 HP to make a viable DB+TB in a single airframe.
We (I, you, some other person) can be misleading in our statements; the SBD made no statement, so it can't be misleading? But okay, even if it is 1200 HP for take off it is not quite 1600+ HP for the SBD-5s.
The Aichi Val also didn't have wing fold.
Unfortunately, people were too late to pick up on Fowler flaps for carrier-borne aircraft - that can shave a lot from required power or from required wing area.
This ship had, most probably.
Italian battleship Giulio Cesare - Wikipedia
(Frogmen theory is fascinating but is not given any proof beyond the hearsay, so far)
Shortround6
Major General
Top of page 77 or the referenced book;
"This double discontinuity in the structure lead to a weakness and the Belfast broke her back at this point when mined (see Chapter 10)"
In Chapter 10 page 161 "The outer bottom failed in compression, the flat keel being fractured. There was a severe buckle, 14 in deep, in the upper deck and there were several fractured plates in the deck. Altogether the the ship was bent upwards by some 4ft 6in."
Emphasis added. We may have different ideas of what "breaking the back" of ship means.
Shortround6
Major General
It depends on what you are trying to do.
The Avenger had a rather generous split flap, it also had a rather generous wing. However Fowler flaps don't do as much for take-off as they do for landing.
The US wanted to fly-off their planes in quick succession. Not resort to catapults unless absolutely necessary. A minimal flap angle may help, a large flap angle may hurt do to drag.
It also complicates the wing fold. One more linkage or actuator system to deal with.
For the US the 1500-1600 engine was in the works in 1938-39. It may not have gone into service with the Navy until 1942 but the engine existed, it was in small scale production and could have been seen as low risk.
Lets remember that the Curtiss SB2C was in design/development months before the Avenger. It took longer to get it to service status.
Lets also remember that this
had only been in service for around year when work started on the SB2C and the Avenger.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
These images are from Shattered Sword, 1st paperback printing.
What bombs do to Carriers and what they do to heavy cruisers. The Hiryu had to be scuttled by torpedoes. The Mikuma went down without further "assistance".
A good illustration of what has been discussed here.
I'm trying to figure out how to post the illustration on page 338 of the Kaga without it being weirdly rotated. The single bomb dropped by Dick Best turned the Kaga into the world's largest canoe. Yet it still had to be scuttled by torpedo.
What bombs do to Carriers and what they do to heavy cruisers. The Hiryu had to be scuttled by torpedoes. The Mikuma went down without further "assistance".
A good illustration of what has been discussed here.
I'm trying to figure out how to post the illustration on page 338 of the Kaga without it being weirdly rotated. The single bomb dropped by Dick Best turned the Kaga into the world's largest canoe. Yet it still had to be scuttled by torpedo.
Attachments
fubar57
General
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
And another tip of the braided hat to fubar57.
Fowler flaps certainly do a lot for improving take-off capabilities. Unfortunately, the simplest Fowler flap, as the one installed on the Lockheed Electra in 1937, took a a few years to be installed on aircraft needing it most - the carrier-borne aircraft.
This is why Fowler flap is good/great - not just that it increases the wing camber, it also increases wing area thus reducing wing loading.
Agreed all the way.
The fact that no one made a combined monoplane carrier TB/DB before those engines arrived seems fairly convincing.
I gave the SBD case (case =design history) as a statement. Again, the SBD-5 even with extra power couldn't carry enough fuel with the 1600lb bomb to make a viable carrier operable aircraft and so this is an example that proves that 1200hp wasn't sufficient. The Val wasn't designed to carry a torpedo or a single bomb over 550lb, but in fact, it did have folding wings, albeit only the outer 6 ft of each wing.
Fairey Barracuda - 1300 HP, stressed for dive bombing, carried a torpedo.
My point was that the 1600 HP figure is arbitrary. An aircraft can carry both a hefty load and be stressed for dive bombing, especially if the designer knows how to have proper flaps on it's A/C.
Your addition of combat range kinda moved the goal post.
The Barracuda 1 used a Merlin 30* and was found to be underpowered and was never used operationally as it's TO run was too long for carrier operations. The Barracuda 2 used the Merlin 32 with 1625hp on TO, and so it actually proves the point that ~1600hp was needed.
Designing an aircraft with all the needed qualities, but with insufficient range, to save weight would be rather pointless.
The Aichi B7A is another example of a combined TB/DB and was designed around an ~1800hp engine.
*The Merlin 30 had it's boost limit raised to 16lb in Jan 1942:
http://www.wwiiaircraftperformance.org/merlin-ratings_3jan42.jpg
and would have provided ~1500hp at 16lb boost. However this increased rating seems not to have been used for Barracuda 1 trials.
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Looking at the photo's of Kaga Hiryu and Mikuma they didn't sink from bomb hits alone but does it really matter, all three while still afloat are still total loses.
