Let's talk about SBDs

[NTGray]

I haven't been able to find a definitive online answer to a simple question, so I figured I would ask the experts here:
What was the normal altitude for an SBD Dauntless pilot in a vertical (70°) combat dive to release his bomb and begin the pullout?
A long time ago I read a historical novel that began with Midway and continued to Guadalcanal, and it stated somewhere that bomb release was at 2700 feet, but since then I've read lower figures, even as low as 1000 feet, and I really don't have a feel for what figure seems reasonable. How fast was the plane traveling downward with dive flaps extended?

 

[MIflyer]

I recall hearing a Midway SBD pilot say they kept climbing, presumably as they burned off fuel, and they were at 20,000 ft by the time they got to the IJN fleet.

And in fact my HS physics teacher flew the final acceptance test on the XSBD, which involved diving from 20,000 ft with a live 500 lb bomb. The Douglas company pilot refused to fly with live ordnance and so they paid my teacher $500 to do the test flight.

As for pull out altitude, that would depend on various factors, including terrain, but I think the biggest factor was the target moving. If the targeted ship is moving and maneuvering then you have to get closer to get a hit. Somewhere I've got a book by a guy who flew Curtiss SB2C Helldivers and it probably has more info than anything else that comes to mind. Also, the USAAF A-36A had a best speed altitude of only about 5000 ft, so I would guess that is the altitude they used, Of course the USAAF would not have been thinking of attacking ships.

One thing I was wondering is if anyone has ever read of an SBD shooting down another aircraft except in self defense. The guy flying the SB2C described his flight of four Helldivers attacking and shooting down a Betty bomber over Taiwan. SBD's were sent out at Coral Sea to defend against IJN torpedo bombers but I think the only ones to score kills were fighting Zeros. By the way, Maj Howard of CMH fame thought that using SBDs as fighters was insane.

 

[GregP]

The Planes of Fame operates a genuine SBD-5 Dauntless. From people who fly it, I can tell you it feels like you fly into Elmer's glue when you deploy the dive brakes. So, the 70° dive is nowhere near as hard to pull out of as you might think because the SBD isn't really going all that fast on the way down with the dive brakes open. Maybe 170 - 210 mph, making the pull-out nowhere near as tough as if it were going 450 mph+ on the way down. It also makes aiming easier then if going faster, too. The guys who fly iy all say it would be relatively easy to hit something, assuming a decent pilot who has practiced the operation.

The SBD Dauntless is generally credited with shooting down a total of about 138 enemy aircraft including those shot down by the rear gunners. Not sure how many were at Midway or the percent by guners / pilots.

 

[ThomasP]

re SBD dive procedures

EwanS covered this to a fair degree here:
"SBD dive bombing procedures"

ie begin pullout at 3,000 ft and release bomb at 2,500 ft.

I would assume that the reason to begin pullout before bomb release is to ensure that the aircraft has a positive g to help in bomb aiming and staying away from the bomb after release.

I added a bit here:
"SBD dive bombing procedures"

In addition to what I already posted:

It would only take about 3000 ft vertical height to go from 0 downward velocity at wing/nose over from cruise altitude to 240 knots downward velocity with dive brakes deployed - assuming that at least 80-90 knots ( ie IAS remains above stall speed) is retained during the change form horizontal flight to diving flight.

If the procedure laid out in the book EwanS quoted is anywhere near what was actually used, then the 240 knots at ~70° steady dive speed with dive brakes deployed (as referenced from Best) would be reached before the start of pullout at 3,000 ft altitude - mentioned in EwanS's post - and should be readily achievable from somewhere above about 6,000-7,000 ft altitude.

The procedure in the post by EwanS also says that they usually started their attack dive (at least I think that is what is meant) from '10-12,000 ft'. This would give the pilot about 10-15 seconds for lining up on the target before reaching the start of the pullout at 3,000 ft altitude.

(I think - if I did my math right)

 

[MIflyer]

From people who fly it, I can tell you it feels like you fly into Elmer's glue when you deploy the dive brakes.

The dive brakes on the SBD are friggin' HUGE! And they found out on the A-36A that you BETTER open those very much smaller dive brakes BEFORE you go into the dive or almost immediately the Apache will be going so fast that it'll be too late to open them.

 

[RCAFson]

I haven't been able to find a definitive online answer to a simple question, so I figured I would ask the experts here:
What was the normal altitude for an SBD Dauntless pilot in a vertical (70°) combat dive to release his bomb and begin the pullout?
A long time ago I read a historical novel that began with Midway and continued to Guadalcanal, and it stated somewhere that bomb release was at 2700 feet, but since then I've read lower figures, even as low as 1000 feet, and I really don't have a feel for what figure seems reasonable. How fast was the plane traveling downward with dive flaps extended?

A lot depends on the target type and the bomb type. if the SBD is attacking a fleet carrier in 1942, then it will be delivering a 1000lb GP bomb and the release altitude will be a low as possible to ensure a hit and still safely pull out of the dive. OTOH, in 1944 that 1000lb bomb might be AP and be dropped on a battleship, and then the release altitude is as high as possible, to ensure a high striking velocity for good armour penetration, but low enough to have a reasonable probability of a hit.

 

[PStickney]

A lot depends on the target type and the bomb type. if the SBD is attacking a fleet carrier in 1942, then it will be delivering a 1000lb GP bomb and the release altitude will be a low as possible to ensure a hit and still safely pull out of the dive. OTOH, in 1944 that 1000lb bomb might be AP and be dropped on a battleship, and then the release altitude is as high as possible, to ensure a high striking velocity for good armour penetration, but low enough to have a reasonable probability of a hit.

Which, given the Danger Close distance for a 1,000 lb bomb means that you start pilling out at 2,000 - 1800 or so ft, rounding out at about 700 ft - where not only might you just frag yourself, but the Japanese Light AAA would actually be dangerous.

 

[RCAFson]

Which, given the Danger Close distance for a 1,000 lb bomb means that you start pilling out at 2,000 - 1800 or so ft, rounding out at about 700 ft - where not only might you just frag yourself, but the Japanese Light AAA would actually be dangerous.

Fortunately for the SBDs the IJN tended not to use a ring formation for carrier escorts as per the USN, so the density of IJN light AA was fairly low in 1942.

 

[Thumpalumpacus]

One thing I was wondering is if anyone has ever read of an SBD shooting down another aircraft except in self defense. The guy flying the SB2C described his flight of four Helldivers attacking and shooting down a Betty bomber over Taiwan. SBD's were sent out at Coral Sea to defend against IJN torpedo bombers but I think the only ones to score kills were fighting Zeros. By the way, Maj Howard of CMH fame thought that using SBDs as fighters was insane.

In the same action wherein Butch O'Hare shot down all those Bettys in Feb 1942, one of the surviving bombers was shot down by an SBD returning from a scouting mission, if my memory is correct. I think the Betty was already damaged. I'll go dig out First Team to confirm.

ETA: Lundstrom credits one Betty in that action to Lt Edward Allen flying in an SBD.

 

[PStickney]

Fortunately for the SBDs the IJN tended not to use a ring formation for carrier escorts as per the USN, so the density of IJN light AA was fairly low in 1942.

Japanese Light AAA was never what would be considered sufficient by U.S. or even British standards.
Their primary weapon was the 25mm triple, short ranged and not heavy hitting. They never managed anything mid-range, like the 40mm Bofors.

 

[GregP]

Not sure if everyone knows it, but the dive brakes on the A-36 are rather unique. There is a brake on the top of the wing and one on the bottom of the wing, and they work simultaneously and are on pivot pins. One set is hinged at the front of the brake and one set is hinged at the rear of the brake, so the forces to extend or retract them cancel each other out, making them easy to deploy at any speed.

Not so on the SBD. The dive flaps hinge at the front and are hydraulic. They look just like large flaps with holes drilled in them. SBD brakes below, and not fully open.

 

[MIflyer]

The A-36A dive brakes were based on those of the Vultee Vengeance - one might even say an exact copy - made by another Los Angeles County aircraft manufacturer - and had a somewhat spotty operational record. When the first A-36A's were delivered to the Med Theater they had problems getting the hydraulically operated dive brakes to work reliably. It seems likely that they did not get all the air purged out of the hydraulic system. On some aircraft the dive brakes were wired shut but this situation was not universal, nor did it persist.

 

[GrauGeist]

The SBD's lower dive brake panels are actually continuous along the bottom.

Here is excellent artwork of Swede Vejtaska's SBD-3 at Coral Sea.

You can see the just how large the dive-brakes are.

 

[MIflyer]

You can see the just how large the dive-brakes are.

When I was in high school I read a novel in which the dive brakes on an SBD were described as being "as large as basketballs." I thought of my 1/48 Monogram SBD and said "No Way! Must be more like the size of baseballs!" But indeed, basketballs are a lot closer. Note that the holes in the dive flaps of the SB2C appear to be not as large, although the general arrangement is similar.

Funny story about an SBD. Following the attack on the IJN carriers after the Battle of Leyte Gulf, the strike force were coming back to the carriers in the dark and low on fuel. So they were landing on whatever carrier they could find. An SBD landed on a carrier that was not equipped with SBD's and the pilot was told, "Taxi forward and fold your wings." The pilot replied that the wings did not fold. The response from the deck crewman was, "Well, fold them anyway!"

 

[Steve Hnz]

Maj Howard of CMH fame thought that using SBDs as fighters was insane.

M MIflyer For the uninitiated, which Major John Howard are we referring to & who or what was CMH? Accounts I've read of the battle of the Coral sea indicate the SBDs were used as fighters because they were short of the real things, needs must as it were.

 

[MIflyer]

which Major John Howard are we referring to & who or what was CMH

Maj John Howard, USAAF, P-51B "Ding How!" Congressional Medal of Honor, former Flying Tiger and before that, USN pilot.

 

[Steve Hnz]

Maj John Howard, USAAF, P-51B "Ding How!" Congressional Medal of Honor, former Flying Tiger and before that, USN pilot.

Thanks for that clarification, I did wonder that but struggled to see where his knowledge of the SBD might have come from, although his knowledge of air fighting per se is in no way in question.

 

[MIflyer]

There has not been much written about the Coral Sea battle, probably not 10% of what has been published about Midway. But the Dogfights video claims that the SBDs were sent out to intercept Kate torpedo planes. Okay, between a Kate and an SBD, I'll bet on the SBD getting the Kate unless it involves a long chase.

But instead of Kates they found Zeros. And most of the SBDs just flew like dive bombers, except for one guy who actually flew his like a fighter.

 

[RCAFson]

There has not been much written about the Coral Sea battle, probably not 10% of what has been published about Midway. But the Dogfights video claims that the SBDs were sent out to intercept Kate torpedo planes. Okay, between a Kate and an SBD, I'll bet on the SBD getting the Kate unless it involves a long chase.

But instead of Kates they found Zeros. And most of the SBDs just flew like dive bombers, except for one guy who actually flew his like a fighter.

There were several Kates shot down by SBDs on CAP at Coral Sea. Lundstrom:

From a correlation of Japanese and American sources, it appears reasonable that the F4Fs actually shot down no Zeros, but perhaps splashed three dive bombers and one torpedo plane, while the SBD crews accounted for no Zeros, but downed one dive bomber and five torpedo planes—total ten Japanese aircraft destroyed by aerial engagement. American antiaircraft fire from the ships likely destroyed one dive bomber and two torpedo planes.

 

[GrauGeist]

The SBD was indeed used as supplemental CAP - at that point in the war, you used what you had available.

The Dauntless was far from a Wildcat, but it certainly was not helpless.