Why was the SBD such an effective aircraft?

Schweik said:

The supply ship HMAS Patricia Cam was sunk in this fashion near Wessel Island on 22 January 1943. The store ship Macumba was also sunk by float-planes at Millingimbi on 10 May, although on this occasion a Spitfire from No. 457 Squadron managed to shoot down one of the float-planes.[Note 4]"

Love the silent dive bombing strategy.

Drama! Maybe we should write a screenplay!

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A movie set in this theatre would be great. RE the Patricia Cam, its sinking took a sinister turn - https://www.ozatwar.com/japsbomb/kentishaffair.htm

fliger747 said:

Float versions were produced of the Wildcat and Spitfire V, though not produced as far as I know. I wonder what the ins and outs were of single float versus twin floats? Then there was the C47 on floats...

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From what I remember, twin floats tend to have less drag than a single float, but either type could double or worse a reasonably clean aircraft's zero-lift drag.

It's funny Supermarine started out as a float plane company, but the Allies never came up with a good float plane fighter until the War was basically over. The Curtiss SC which was probably the last good plane made by that company. It would have been an interesting contender in 1942 or even 43 in some of those more remote areas. I'm not sure if it could hang with a Rufe or not but it should have been close, it had a 30 mph speed advantage and decent armament of two .50 cal guns (though the Rufe had 20mm). The only flaw is it didn't have very good range for a scout.







I think the float plane scout fighter and general purpose / scout bomber aircraft was a good idea for certain regions and definitely had a niche.

I remember reading the He 115's were doing that same trick of cutting engines off for a glide-attack to surprise ships at one point.

Having float plane aircraft like that available in the arsenal means the ability to project air power, albeit of a somewhat lesser capability, into remote areas and without risking an aircraft carrier. Once in position they could be supplied by a seaplane tender or even a submarine.

The French had some interesting float plane designs though of course they never came to their potential...

The French float plane fighters had no potential. All the Loire 210 (lower two photos) needed was new wing, a new engine, more guns, a whole new system of bracing the floats and to get rid of the braces on the tailplane. Top speed was under 190mph.

Well, you may be forgetting the Loire 210 was really a pre-war design? Perhaps you should compare it with the float plane competition... lets do just that since I love seaplanes.

The French Seaplane scouts
Loire 210 - 186 mph, 4 x .30 cal, range 750 km (from 1939)
Bernard H 110 - 204 mph, 2 x .30 cal, range 750 km (one prototype in 1935)
Latécoère 298 - 167 mph, 3 x .30 cal, range 1,500 km (it was a torpedo bomber w. 1500 lb bomb load, from 1938)

Single engine seaplane scouts from around the world
Fairey Seafox - 124 mph, 1 x .30 cal, range 708 km (biplane, from 1937)
Supermarine Walrus- 130 mph, 2 x .30 cal, range 966 km (biplane, from 1935)
Curtiss SOC "Seagull"- 165 mph, 1 x fixed .30, 1 x rear firing .30 cal, range 1,086 km (biplane, from 1935)
Vought OS2U "Kingfisher" - 164 mph, 1 x fixed .30 cal, 1 x rear .30 cal, range 1,296 km (from 1940)
Grumman J2F "Duck"- 190 mph, 1 x rear firing .30 cal, range 1,255 km (biplane, from 1936)
IMAM Ro. 43 - 186 mph, 2 x .30 cal, range 1,500 km (biplane, Italian, from 1935)
Nakajima E8N "Dave" - 186 mph, 2 x .30 cal, range 898 km (biplane, from 1935)
Aichi E13A "Jake" - 234 mph, 1 x .30 cal mg, range 2,089 km (from 1941)
Yokosuka E14Y - 153 mph, 1 x .30 cal (this was a submarine based lightweight aircraft, from 1942)
Aichi E16A Zuiun "Paul" - 270 mph, 2 x 20mm, 1 x 13mm, range 1,176 km (from 1944)
Mitsubishi F1M "Pete" - 230 mph, 2 x fixed .30 cal, 1 x rear firing .30 cal, range 740 km (from 1941, biplane)
Arado Ar 196 - 193 mph- 2 x fixed 20mm, 2 x .30 cal, range 1,080 km (from 1938)
Northrop N-3PB - 257 mph, 4 x 12.7mm, range 1,609 km (small number used from April 1941)
Curtiss SO3C "Seamew" (aka "Sea Cow")- 172 mph, 1 x 12.7mm fixed, 2 x 12.7mm rear, range 1,800 km (1942, considered a design failure and withdrawn from service by 1944)
Nakajima A6M2-N "Rufe" - 270 mph, 2 x 20mm, 2 x .30 cal, 1,148 km (from 1942)
Curtiss SC-1 "Seahawk" - 303 mph, 2 x .50 cal, range 1,006 km (from 1945)

Multi engine seaplanes and flying boats
He 115 - 200 mph, 3 x 30 cal mg
CANT Z.506 - 230 mph, 1 x 12.7mm and 3 x .30 cal mg
PBY Catalina - 190 mph, 2 x 12.7mm, 3 x .30 cal
Do 18 - 155 mph , 2 x .30 cal
Do. 24 - 205 mph, 1 x 20mm, 2 x .30 cal
H6K "Mavis" - 211 mph, 1 x 20mm, 4 x .30 cal
H8K - 290 mph, 5 x 20mm cannon, 5 x .30 cal (from March 1942)
Short Sunderland III- 210 mph, 2 x 12.7mm, 14 x .30 cal
BV 138 - 177 mph, 2 x 20mm, 1 x 13mm, 1-3 x .30 cal
BV 222 - 205 mph, 3 x 20mm, 5 x 13mm (from August 1941)

That is what I could come up with. Did I miss any? Range is from the wiki's so could certainly be off.

Of the single engine planes, I'd say the French ones are a bit better than the middle just comparing armament and speed. The Loire is about in the middle of the pack on speed but more heavily armed than most, it looks quite good next to the Kingfisher (for combat at least, if not range) which was probably the most important Allied float plane scout, and competetive with the "Dave" which would be the Japanese equivalent. The Rufe of course stands out above all the others but it didn't become operational until 1942. The "Paul" also looks good but only 24 were made and it was not in the War until 1944. The "Jake" really stands out by it's incredible range, which is the single trait probably most valuable for most of these planes as scouts - range really needed to be good. The FM1 by contrast had quite limited range though it was much better for combat.



The only Allied single engine seaplane which even comes close to the "Rufe" by the mid-war period was the (to me, quite impressive) Northrop N-3P but it was also made in very small numbers (less than 20) and basically only used by the Norwegians out of Iceland. It was heavily armed, fast and had a good range. It was actually supposed to get 2 x Oerlikon 20mm cannon but wasn't armed in time for the outbreak of the war. The Ar 196 was a dangerous opponent just because of the heavy armament and you can see where the F1M "Pete" looks pretty good based on speed and what we know of it's maneuverability, though it was lightly armed. The Seahawk looks good but as I said already it really came too late.

As for the Loire 210, I think a slightly bigger engine would have made it quite effective. It had a 720 hp but that could have been upgraded to a 900 or 1,000 hp engine fairly easily, which should have put the speed well over 200 mph and thereby quite competitive with most of the other single-engined types up to 1942 or so. Just the fact that it was a monoplane would make it superior to most of the other early war designs. Not sure why it would need a different wing. The guns are pretty decent by early war standards but adding a 20mm cannon would significantly improve it's utility.

The other one I posted, the Bernard H 110 managed 200 mph with a 700 hp engine which isn't bad for 1935 though the manufacturer went bankrupt.

Of the mult-engined planes, some of the early war ones could be intercepted but many are too heavily armed for that Loire, with the H8K, Sunderland, BV 138 and BV 222 all probably well out of reach. The H8K, Sunderland and BV 222 were heavily armed enough so as to be dangerous for even front line land based fighters to attack. H8K in particular really looks like a beast on paper though I know many were shot down.

The thing to keep in mind about seaplanes is that they could operate in remote areas often far out of reach of land based aircraft. A float plane that can tangle with short to medium ranged carrier or land based planes like the "Rufe" (and I guess to a lesser extent, the "Pete") is kind of a next-level creature. Most of them will only face other float planes and long range maritime patrol aircraft like a FW 200 or a PB4Y, and then often only rarely.

If the enemy makes sufficient efforts it can get carrier planes or long ranged land based fighters / mulitrole planes like a Beaufighter or a Ju 88 in range of your seaplane base, it could be trouble for the seaplanes. But they could also just be moved to another more remote base (depending on the Tactical / Operational situation).

The ideal role for the seaplane was to project power where aircraft would not normally be. Like from remote pacific Islands without land bases, or as scout planes paired with surface warships like Cruisers or armed merchantmen. Think how useful a "Rufe" would have been for the Royal Navy as an alternative to a Sea Hurricane for North Sea convoys. No need to ditch in the sea after chasing away that Fw 200.

For that matter the Northrop N-3P might have been a good alternative too.

Aichi M6A "Seiran"
Max. range: 738 miles
Max. speed: 295mph
Armament: one flexible 13mm MG, one Type 91 torpedo or two 550lb. bombs/one 1875lb. bomb.

Yokosuka E14Y "Glen"
Max. range: 575 miles.
Max. speed: 153mph.
Armament: one flexible 7.7mm MG, two 168lb. bombs.

GrauGeist said:

Aichi M6A "Seiran"
Max. range: 738 miles
Max. speed: 295mph
Armament: one flexible 13mm MG, one Type 91 torpedo or two 550lb. bombs/one 1875lb. bomb.

Yokosuka E14Y "Glen"
Max. range: 575 miles.
Max. speed: 153mph.
Armament: one flexible 7.7mm MG, two 168lb. bombs.

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Good catch! I forgot the sub-launched seaplanes. Another fascinating sub-genre. I left out the M6A because I don't think it ever saw combat, despite the promising design. The E14Y was used though so I've added it to my post.

I got to see the Northrop N-3P up close. Tthey raised from a fjord and Northrop workers restored. It was featured at the Torrance Armed Forces Day parade in 1982. Beautiful airplane, like a sleeker SBD, which was also originally designed by Northrop.

It really is a beautiful aircraft.



Interestingly Douglas made an export version of the Northrop A-17 as the A-33, which they called a "ground attack fighter". I saw nothing about dive bombing though it did seem to have dive brakes for dive bombing based on the photos. Performance was comparable to the SBD with basically the same engine, and it had 2 x .50 and 4 x .30 cal guns, as well as supposedly a 2,000 bomb load (four wing hard points stressed for 500 lbs each).

The Douglas SBD was also derived from a Northrop design, the BT-1 so there seems to be some link to the two aircraft families so to speak. Northrop was a subsidiary of Douglas.

Despite the clean lines it was not as impressive as you would like. Probably a bit of extra drag caused by the very large (47') wingspan, and the wheels were exposed on the front which probably also caused drag.

It did see some action in the Dutch air forces but was used as as fighter and quickly slaughtered according to the Wiki

It brings up another question about the SBD. How good of a fighter could you make if you stripped away dive brakes, rear gunner, rear gun and ammo, rear gunner armor, special dive-bombing bomb rack, the extra set of controls for the rear gunner, the back half of the cockpit and so on. That should save a good bit of weight, maybe 1,000 lbs? That might get close to Wildcat performance.

SBD-5 empty weight was ~ 6,400 lbs, F4F-4 was 5,800 lbs. If you dropped the SBD down to an empty weight of 5,500 lbs or so I would think it might make a competitive carrier fighter. Probably more useful in Scout-dive bomber configuration but it's interesting to think about.

I saw the M6 Seiran they were restoring at Sliver Hill, sitting right next to the Enola Gay. The type almost saw combat., They were going to bomb the Panama Canal. The sub surfaced and received a radio message about the atomic attack on Hiroshima. They, tossed the airplane overboard and returned to Japan.

Personally I think the Marines on Midway would have been much better off with the F3F-3 than the F2A. I talked to a former USMC pilot who said that when the F2A came out the Marines at San DIego were mad as hell. The East Coast USMC got the new F2A and they were stuck with the old F3F's. Little did they know.....

And yet the Finns did so well with it. It may have just needed some weight cut out.

Apparently the Latécoère 298 saw some action. From the wiki:

"The Laté 298s first saw action during the Battle of France in 1940. They were used at first for maritime patrol and anti-submarine duties, but did not meet any German ships. Later, as the Wehrmacht drove through France, they were used to harass and interdict armoured columns. Despite not having been designed for this role, they suffered fewer losses than units equipped with other types.

After the armistice of June 1940, the French Navy under the Vichy regime was allowed to retain some Laté 298 units, and captured aircraft were used by the Luftwaffe.

After Operation Torch, French units in Africa sided with the Allies. In this guise, the Laté 298 was used for Coastal Command missions in North Africa, in cooperation with Royal Air Force Wellingtons.

The Laté 298's final combat missions were flown during the liberation of France, where they were used to attack German shipping operating from strongholds on the Atlantic coast.

The last Laté 298s were retired from active service in 1946, but continued to serve as trainers until 1950."

A float plane torpedo bomber with that kind of range seems like it could have had an impressive niche both in the Pacific and the Med. I wonder what kind of combat record it had, did it sink any German ships? How good were the French torpedoes?

The stripped down SBD, gunner and aft cockpit removed etc, probably looks almost exactly like a Zero..

A stripped SBD looks even more like a T-6 made to look like a Zero. It would no more be a competitor to the Zero than would a modified T-6.

The Finns had the early F2A's, provided from US Navy stocks, not export models built to European standards. They lacked many of the weight adding upgrades of the later models.

The E14Y was also one of the few enemy aircrat to ever attack the continental U.S.

In September '42, an E14Y launched from I-25 attacked twice (9th and 29th), near Brookings Oregon.

MIflyer said:

A stripped SBD looks even more like a T-6 made to look like a Zero. It would no more be a competitor to the Zero than would a modified T-6.

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Well the T-6 had / has a 600 hp engine (and managed 200 mph with that), the SBD like the F4F had a 1,200 hp engine, so with double the horsepower I think they would actually be closer to competitive.

The T-6 is also a two-seater whereas the hypothetical SBD fighter would be a single-seat aircraft.

Don't forget about the N1K1

Well, the Aussies did build a single seat T-6 with an R-1820, the Boomarang, armed the same as a Spitfire V. And it never shot down an enemy aircraft. They used to get P-39's to escort it on ground attack missions.