How did B-17 and B-24 formations avoid shooting each other?

[Thumpalumpacus]

Yeah, I'm not sold. Top turrets can't shoot downwards, waist gunners have no time to line up shots, so you've got the chin and the bubble for straight-line shooting for a pass. Hope you armor them up for those 3000' passes ... which will only make them slower.

There's no M-61 in 1943, and you're not squeezing a 105 or even a 75 in there sideways. Orbiting in .50 cal range when the enemy AA has quad 20s might not be conducive to health and well-being.

 

[Reluctant Poster]

Perhaps the gunship could work in concert with a team of Tiffies or Jugs, who's job was to sweep the area for flak batteries prior to the heavy's gun-run?

Neutralizing flak was not easy and generally only temporarily. An orbiting gunship would had a very short life expectancy.

One pass only. Any flak position not destroyed on the first pass would come back in to action

 

[Admiral Beez]

This isn't New Guinea. German AA is solid. Get in, shoot up, GTFO. Do low-and-slow at your own peril.

Then let's change the theatre to where it might be useful. We can all list off the reasons why a B-17 CAS gunship wouldn't, couldn't or shouldn't be feasible. The fun is in overcoming our contrarian tendencies and trying to make it work with the technology at hand. Even if we fail miserably like World War II's Worst Airplane and Second World War Weapons That Failed.

 

[GrauGeist]

The idea was to have fixed weapons firing sideways or downward.

I'd also suggest removing turrets and fair over the waist positions to eliminate drag.

One similar concept was tried by the Soviets with their Tu-2Sh, which had 88 PPSh-41 SMGs in it's bomb bay, aimed downward at a 30° angle.

 

[Holtzauge]

View attachment 799079
Neutralizing flak was not easy and generally only temporarily. An orbiting gunship would had a very short life expectancy.

View attachment 799093
View attachment 799095
One pass only. Any flak position not destroyed on the first pass would come back in to action
View attachment 799096

View attachment 799094

Well sometimes strafing was indeed effective. At least if you ask those on the receiving end:

At our local glider-club outside Stockholm, we in the late 1970's had a lady who had been a so-called Flakhelferinn on a Richtungshörer during the war.

TBH, since she had nothing negative to say about what transpired in Nazi Germany during the war, and had that superior attitude you can sometimes find in some Germans, I did not find her a very likeable person. OTOH, she was a bit unstable and was absolutely livid about Russians, so it could very well be so that she like so many other German women had not fared too well under the Russian occupation before making her escape to Sweden.

Be that as it may, she once told us youngsters an interesting war story: One day when they were manning the listening station as usual (she said she was 19 at the time as I recall it), as the youngest in the crew it fell on her to run errands. So when it was time for lunch she was as usual sent packing to get it. However, on this particular day, when she returned, a lot of her friends were dead. Killed by a strafing fighter while she was away getting the chow.

So it goes, as Kurt Vonnegut used to say......

 

[DDonSS3]

I'm pretty sure those R-2600s were added when the PB4Ys were converted postwar (by civilian companies, not the USN) for water-bombing forest fires in the western US. I am certainly willing to be proven wrong, though.

It was able to keep up with B-17s when loaded with bombs, but not on the return back.

More HP was needed.

Postwar, USN Privateers, very similar to the B-24, were retrofitted with R-2600 from the B-25 for better performance
View attachment 798820

with only minor work to mate up.

One way to improve that return home performance.

That said, The Gunship escort never worked well for anybody

 

[marathag]

I'm pretty sure those R-2600s were added when the PB4Ys were converted postwar (by civilian companies, not the USN) for water-bombing forest fires in the western US. I am certainly willing to be proven wrong, though.

Yes, that was all private by the eyeball and tape measure hangar engineering(Looks like that will fit!), I should have had wrote 'surplus ex-USN Privateers' to make that more clear.

Was solid enough that the company got the FAA to do a STC on that.

 

[Peter Gunn]

EXCELLENT Info. Or as the RAF chaps said, "Pukka gen." Sharing widely.

Um... huh?

Sorry, my midwest vocabulary is failing me on that one.

 

[Shortround6]

I'm pretty sure those R-2600s were added when the PB4Ys were converted postwar (by civilian companies, not the USN) for water-bombing forest fires in the western US. I am certainly willing to be proven wrong, though.

Yes, that was all private by the eyeball and tape measure hangar engineering(Looks like that will fit!), I should have had wrote 'surplus ex-USN Privateers' to make that more clear.

Was solid enough that the company got the FAA to do a STC on that.

I believe you are correct.

I will also note that the R-2600s were NOT turboed and while the R-2600s gave a lot more power for take-off they didn't give much more power in the high teens or into the 20s than the R-1830s in the B-24s did.
The planes that got the R-2600s seem to be PB4Y-2s that were built without turbos and used R-1830-94 engines that were rated at 1350hp for take-off. They had the taller single tails and a longer fuselage/nose.

As far as some of the engine swap nonsense goes, as a contrarian, this late Twin Wasp went about 1573lbs and was a two speed single stage engine. It was about 400lbs lighter than the Wright R-2600 that was swapped in.
Wright never got a turboed R-2600 into service in anything.
For the B-17 the 9 cylinder R-1820 engines were just over 1300lbs weight. A lot harder to get the just under 2000lb R-2600s to fit (balance) and without turbos the power at altitude doesn't work.
The Firefighting Privateers also had all their combat gear (guns/armor/self sealing tanks)) stripped out and probably new radios and a crew of 3-4 men? A lot of room to juggle weight around. They also were not trying to fly 500-1000 miles each way to drop their load.

Comparing modern (late Viet Nam ) era attack aircraft to WW II is a fools errand.
Different guns, different ammo, different bombs/underwing ordnance and.............
much more importantly much different aiming systems and sensors.
An early AC-47 might have used gum stuck on the side window but they soon escalated to a fighter type reflector gun sight and then night vision, and RF sensors (they could locate trucks by the RF signals given off by the ignition systems) and infrared on the later gun ships and electronic sights. They also operated a lot a night to minimize the effects of the less sophisticated enemy air defenses. At some point the pilot stopped aiming the guns and it done by mission operators in fuselage of the plane at sensor/weapons consoles.
Orbiting in daylight was just offering themselves up as targets.

I would also note that there were ways to improve firepower during WW II that did not involve using time machines, IF you willing to pay the cost in weight.
A 20mm Vulcan gun weighs about double what a 20mm Hispano does. Granted it fires a lot faster. But they also rarely operate the Vulcan at peak rates of fire for ground attack.
4200rpm or less vs the 1200-1500rpm for two Hispanos. It also becomes a question of weight of the ammo. 500 rounds of Vulcan gun ammo weighs about 225lbs. Adjust rate of fire as you see fit and/or adjust weight of ammo.

They stuck an electric motor underneath a Gatling gun before 1900 with a pair of pullies and a V belt. The Problem was feeding it. How fast can you move the rounds through the feed system leading to the gun.

Gun system for an F-18. There is an awful lot of 'stuff' that the gun needs to run. The ammo in the 'drum' is in a spool/helix and there are motors that move the rounds to and from the gun (WW II might just eject overboard) but the entire spool/helix rotates inside the exterior casing to feed ammo into the system. You need a fair amount of power to get the system up to speed to feed the rounds to the gun quickly. You also need a way to stop the gun and clear it. Throwing 3-5 loaded rounds out the ejection chute as the gun stops may not be a good idea?

Maybe you could get 3 primitive Hispano guns for one Vulcan gun system as far as weight goes?
Doesn't sound as cool.

 

[marathag]

Comparing modern (late Viet Nam ) era attack aircraft to WW II is a fools errand.
Different guns, different ammo, different bombs/underwing ordnance and.............
much more importantly much different aiming systems and sensor

A-26 saw the end of WWII and the beginning of Vietnam
Some new, some old under the wings, till the wings fatigued out

too many missions, too many loads

For the Waterbombers, it was economy. R-2600s weren't as popular as the P&Ws were, and were good for the expected roll of dropping almost 20,000 pounds of water.
During the War, the R-2600 had it's issues, like no turbo or really advanced supercharger work, so not so good for a high altitude escort.
Point remains, that a few hundred HP more per engine might have been enough for the escort to remain with the lighter bombers on the way home.

 

[Shortround6]

Point remains, that a few hundred HP more per engine might have been enough for the escort to remain with the lighter bombers on the way home.

Kind of depends on at what altitude they were going home at.
The 1700hp the R-2600 engines had at sea level started to taper off at 3000ft in low gear.
If you stayed in low gear the engine might give 1100hp at 15,000ft.
Shifting to high gear gives 1450hp (?) up 10 12,000ft but by 15,000ft the power has dropped to about 1300hp.
Trouble is it keeps dropping. At 20,000ft is is just under 1100hp.
That is at full power (5 or 15 minutes) and at cruise it would be much less.
The Turbo equipped small engines could make 1200hp at 23-25,000ft full power and could make Cruise power at 35,000ft.
B-17 could make 750hp at 35,000 using max lean. and burn around 62 gph (?)
Engines in the B-25 could make about 905hp at 15,000ft max lean and burned around 100gph.
By the time you are trying to fly in the low 20s the turbo engines are going to give more power for less fuel than the R-2600s.

There is no question that taking the turbos out was the right thing for the PB4Y-2s at they rarely (if ever) flew at high altitudes.
The model of R-1830s they used was rather rare (different cylinders and other differences) so getting spares was hard. Going to 'normal' R-1830s means 150hp less per engine for take-off. The R-2600s gave the power needed at low altitude and solved the spare parts problem.

But in WW II trying to shove R-2600s into B-17s (or B-24s) was not going to solve the speed at altitude problem without a whole lot of work (time).

Maybe they could have stuck turbos on the R-2600 1900 hp (BB series) engines and down rated them to 1600-1700hp to help with the cooling but since that engine didn't show up until the last 3-4 months of 1943 it isn't going to solve the escort problem any sooner than the P-38s, P-47s and P-51s did.

 

[yulzari]

Um... huh?

Sorry, my midwest vocabulary is failing me on that one.

Dydh da Peter. As they might say near me. Yer, tis proper job. Duw genes.

 

[buffnut453]

Um... huh?

Sorry, my midwest vocabulary is failing me on that one.

Allow me to translate for you, dear chap!

"Gen" means information, possibly derived from the term "General Information" used in official correspondence. "Pukka" is a borrowed word from the Indian Sub-continent, meaning "solid." Thus "pukka gen" means "solid/reliable/accurate information."

The antonym of pukka gen is duff gen.

Both terms are particularly associated with the RAF but I suspect the terms have a longer heritage than that.

 

[Peter Gunn]

Allow me to translate for you, dear chap!

"Gen" means information, possibly derived from the term "General Information" used in official correspondence. "Pukka" is a borrowed word from the Indian Sub-continent, meaning "solid." Thus "pukka gen" means "solid/reliable/accurate information."

The antonym of pukka gen is duff gen.

Both terms are particularly associated with the RAF but I suspect the terms have a longer heritage than that.

I knew I could count on a fellow Buff lover.

 

[don4331]

A group formation (36 B-17s) would have much less than one cubic mile of airspace in the formation. Said formation would have anywhere from 330 to 400 machine guns pointing in all directions, depending on model. The odds on not catching friendly fire had to be very low.

Actually, you are only really at risk from the immediate 2-5 other aircraft in your portion of the box thanks to gravity:

As you are leading and elevating so your fire hits the attacking fighter, 99.99% of the time before the bullet arrives horizontally at any other block in the box, gravity has pulled it far below (my biggest issue with video games...you fire lasers - no leading/compensating for bullet drop required...)

It's why you see fighters "walk" rounds into the trains/trucks...the drop of the rounds, causes them to fall short, but as you get closer/correct aim, your rounds begin to hit the target.

It's also why a torpedo bomber can't suppress the flak coming at it from the ship; if your aiming your plane so the torpedo arrives where the ship will be, you're pointing to a spot several hundred meters ahead of the target. And your guns firing straight ahead would be firing at air.

 

[Thumpalumpacus]

Actually, you are only really at risk from the immediate 2-5 other aircraft in your portion of the box thanks to gravity:

As you are leading and elevating so your fire hits the attacking fighter, 99.99% of the time before the bullet arrives horizontally at any other block in the box, gravity has pulled it far below (my biggest issue with video games...you fire lasers - no leading/compensating for bullet drop required...)

It's why you see fighters "walk" rounds into the trains/trucks...the drop of the rounds, causes them to fall short, but as you get closer/correct aim, your rounds begin to hit the target.

It's also why a torpedo bomber can't suppress the flak coming at it from the ship; if your aiming your plane so the torpedo arrives where the ship will be, you're pointing to a spot several hundred meters ahead of the target. And your guns firing straight ahead would be firing at air.

Sure, but the bullets from bombers ahead and above you have to go somewhere -- backwards and down, in many cases. Many bombers, and American aircrew, took hits identified as being from .50 cal.

 

[Greg Boeser]

It was not uncommon for trailing, lower aircraft to get pelted with spent cartridges. MTO based B-26s had pans installed under the tail to catch the spent casings and links.

 

[GrauGeist]

A few bombers even got hammered by bombs falling from aircraft above.

That caused a bit more damage than a few stray .50 MG rounds...

 

[EwenS]

A few bombers even got hammered by bombs falling from aircraft above.

That caused a bit more damage than a few stray .50 MG rounds...

As with this RAF B-24 in Italy.

Bombs dropping onto B-24 · IBCC Digital Archive

IBCC Digital Archive

ibccdigitalarchive.lincoln.ac.uk

 

[Peter Gunn]

This piqued my interest so I consulted my uncles (extensive) diary, nothing about friendly fire but, he does say in one entry that spent casings (links too perhaps?) trickling down from the high squadron (or at least high-er squadron) were pelting the windscreen like rain. He doesn't mention if it cracked or chipped the glass though.

Just a small vignette on the topic.