B-17 and B-24: plausible upgrades?

[GregP]

I think the Allison engine, R-2000's, or R-2600's would have been good. A slight reductin in armament along the lines Drgondog suggested would not hurt in a large formnation, but might prove fatal for a straggler. Then again, stragglers were pretty much a target anyway.

Some armor plating along the nose to protect the flight crew froma head on pass might also help. Of course, if you take away weight and then add it back on, would there be enough gasoline left for the mission given the new engines? It would take some figuring.

I'm thinking a strecthed version of the B-26 Maraduer with four R-2800's might have been a good possibility. Longer would give more bomb bay space and the 4 engines would certainly not be more complex than the B-17's and B-24's already were. I've wondered why nobody ever pursured even a prototype of it for a long time. It would look something like the Japanese Nakajima G8N-1 Renzan, which was not produced serially. They only made 4 after the 3 prototypes.

The Renzan was also fast at 358 mph, with a supposed 242 mph cruise speed. Not saying the 4-engine B-26 would have been the same, but would have been a faster airplane than were either the B-17 or B-24, and with the R-8000's, would almost certainly have hauled more payload. The Douglas A-26 could haul a normal load of 4,000 pounds internally plus another 2,000 pounds externally with only two R-2800's.

 

[FLYBOYJ]

So what plausible upgrades could USA undertake, in order to make the B-17 and B-24 better suited for the tasks, even if planes taking those tasks might be contested by enemy actions? There was one real-life upgrade to the B-17, namely the version with V-1710s, so that might get the ball rolling.

You mentioned the V-1710 upgrade for the B-17. Outside of that and the actual evolution both aircraft went through, I really don't think there was much more that could be done to them that would have been real cost or performance effective.

Regarding the B-24 - it's original proposal sketch below...

Because of the time contraints of bidding on the contract that awarded the B-24, the actually production aircraft looked much different. I think, however, Consolidated had this in mind the whole time...

 

[gjs238]

I'm thinking a strecthed version of the B-26 Maraduer with four R-2800's might have been a good possibility. Longer would give more bomb bay space and ehe 4 engine would certainly not be more complex than the B-17's and B-24's already were. I've wondered why nobody ever pursured even a prototype of it for a long time. It would look something like the Japanese Nakajima G8N-1 Renzan, which was not produced serially. They only made 4 after the 3 prototypes.

Martin XB-33 Super Marauder - Wikipedia, the free encyclopedia

Seems they considered "Supering" things before the Super Hornet

 

[GregP]

Thanks gjs328,

I had seen that many years ago and forgotten. Unfortunately they didn't pursue it. The point is they COULD have had them available well before the B-29 and they could have been in the fray in Europe. Alas, they weren't in real life, but it's nice to know they were considered. I suppose there was some reason why it wasn't pursued, and the reason probably included the B-17 and B-24.

Given the specs though, it seems like one or the other should have been replaced with the new design that was faster, had enough range, and hauled a lot more weight. Of course, I'm speaking from hindsight, not from within WWII production realities and I am no doubt unaware of the pressures and resource constraints they were facing at the time, though it would seem as if the Martin project would not take up Boeing or Consolidated resources ... other than GFE (government furnished equipment), of course, such as Aluminum, engines, propellers, etc. .

 

[davebender]

1935. R2600 engine prototype first run.

29 Dec 1939. B-24 prototype first flight.

B-24 could have been designed for R2600 engine from the beginning. There should have been no production delay.

 

[tomo pauk]

So far this is the best information I have about the turbo R-2600.

The second engine might be the C series R-2600, that one was in production from 1944 on.
Installing them, in turbo guise, could be too much for historic B-24. A whole new airframe would indeed be needed for that, as proposed with XB-33.

 

[GregP]

Not sure about the turbo, but the B-25 used the R-2600 and was in sercvice soon enough to fly the Doolittle Raid on Tokyo. It was introduced to service in 1941, so the "Super B-26" COULD have been fielded not much later, with trubos coming later.

Sure, it's a "what if," and I don't like theose much .... but the point is the timeline for European deployment could have been met easily if authorization to proceed had been forthcoming. In the real world it wasn't, of course.

 

[syscom3]

Would take some work, but I would rather see the bomb bays redesigned so that the center structural member is moved outbound to the sides (same as the B29 and Lanc). That way both bombers could carry the large bombs (4000 pounders) internally instead of the drag inducing external hard points.

 

[GregP]

Good point Syscom. I was thinking more of a newer or faster airframe than of the improvements that could be made for operational ease of use on existing airframes. But they are important, too.

 

[Shortround6]

So far this is the best information I have about the turbo R-2600.

Only one A-20 was completed as such out of an order for 63 planes, it was decided to complete the rest as A-20A's without the turbo. Most of these were actually completed as P-70s. 3 were completed as F-3A recon planes. Both the A-20D and O-53 died on the drawing boards, no example ever flew. Not sure about the YF-3 but one source only gives two serial numbers. Flown as YF-3s or converted to/from something else?

Leaving out the turbos probably means a lower than desired cruise height with a trade off from flak. faster speed means less time in flak range at turbo altitudes but lower operational height means more time in Flak range. How close it comes to equaling out I don't know.

The 1200hp engines burned about 50-55 gallons each at around 180mph True. B-17 Cyclones at 2050rpm and 30in MAP. At 210-212mph true the engines were burning 71 gallons each at 2100rpm and 31.5in MAP.

AN R-2600 from a B-25 making 810hp at 15,000ft. (minimum cruising) uses 80 US gallons an hour at 2000rpm and 27in MAP.

An R-1820 in a B-17 can make 1000hp (max continous, NOT Military) at 30,000ft. It can make 1200hp at 27,000ft using Military power.
An R-2600 WITHOUT turbo makes 900hp at 25,000ft at Military power. 1100hp Military at 20,000ft.

This may be why little or no effort was made to re-engine the B-17 and B-24. The R-2600 offered less power at the operational heights wanted over Europe. It weighed about 500lbs more per bare engine and burned more fuel.

 

[tomo pauk]

Thanks for the effort to type out the numbers
You can note that I don't try to push forward the turbo-less R-2600 for the USAF bomber's use in the ETO. My pet engine being the turbo V-1710 for that task. The take off power would also go up, with those installed.

Another ideas: R-2000 in the B-24? Maybe having the engines with water injection, so the take off power can be greater?

Question for people well versed in HP Halifax: was there a difference in speed with differently equipped models, but with same engines?

 

[model299]

I've seen before that the B-24 crews would razz the B-17 crews about arriving back at the base sooner.
The '17 guys would counter that they flew higher and thus were harder to "reach" than the '24s.



The problem with the XB-38 was the additional weight and complexity the installation brought with it.

In fact, the prototype was lost to an engine fire. Sound familiar?

You certainly can't argue about the looks though. They did a great job on those cowls.

 

[GregP]

I understand they "cobbled together" the exhaust manifolds, there being no other application for them, and so they tended to leak after a few hours. If production manifolds had been designed and used, it would not have been a problem ... as it wasn't in the P-38 after the usual teething troubles. We have many P-38 exhaust components today and they work just fine when they get installed in a flying P-38.

 

[bob44]

Would a faster B17 or B24 have helped with bomber losses?

 

[MikeGazdik]

So what plausible upgrades could USA undertake, in order to make the B-17 and B-24 better suited for the tasks, even if planes taking those tasks might be contested by enemy actions? There was one real-life upgrade to the B-17, namely the version with V-1710s, so that might get the ball rolling.

More Mustangs, sooner.

 

[GregP]

A B-17 cruising at 230 mph would have been better than 180 mph. The closing speed would have been less, so the gunnery from both sidres would have been better, and the losses to B-17 bubbers would have been higher ... as might have been the B-17 losses. Without emprical data, we will never really know.

 

[Aozora]

There was an attempt made to modify the B-17 - it was called the "Reed Project" Plane Talking - HyperScale's Aircraft Scale Model Discussion Forum: More Reed Project B-17 photos

Essentially this was a B-17E modified by an 8th AF engineering officer, Major Robert J. Reed. For a start he noted that all operational B-17s were flying with their cg aft of the rearward limit of 32% MAC at the operational weights then in use (early 1943); of course this had bad effects on the stall characteristics, slower cruise speeds, worse fuel economy etc.

Major modifications:
Incorporating Consolidated turrets into nose and tail positions - because the turrets had their own armor plate, which turned with the turret, fixed armor was no longer needed in the nose and rear gunner's compartments: turrets were also equipped with more effective sights and could cover a greater area more effectively than the hand-held weapons.

Change the bombardier's position to a streamlined blister under the nose, closer to the aircraft's cg.

Relocate the radio operator and radios to the nose compartment, rectifying the cg problems and allowing more effective co-operation with the navigator, plus the operator manned the turret leaving the bombardier free to concentrate on one task.

Modifications to the ventral ball turret: remove ammunition boxes from within the turret to the yoke carrying the turret, which also allowed a much increased ammunition capacity of 1,400 rpg. The internal components of the turret were rearranged to provide more room and better accessibility to oxygen outlets, etc which meant that the gunner could now wear his parachute.

Replace the Sperry upper turret with a Martin 250CE unit which was 120 lbs lighter, with more efficient sights, better armor plating and visibility for the gunner, plus it took up less room behind the cockpit and the seated gunner was more comfortable. It was also possible to dispense with the waist guns.

Add a powered twin-machine gun installation in what had been the radio operator's compartment.

Replace the folding bomb bay doors with units that slid forward and aft, meaning that there was far less drag than with the standard doors open.

Overall it was calculated that there would be a decrease in gross loaded weight of 1,000 lbs, while the mean cg would be at 27% MAC, decreasing the stress on the airframe, improving flight characteristics and increasing cruising speed by 10 mph.

From Air Power January 1984 Vol 14, No. 1

The main problem I can see is that with the hinged bomb bay doors bombs could be jettisoned through them, if need be, whereas with the fore and aft sliding units that might not have been possible.

 

[johnbr]

I so a photo with a B-17 with 3 50s cil in the tail.

 

[VBF-13]

Would a faster B17 or B24 have helped with bomber losses?

I'm thinking the same thing. Negligible, if anything. These aircraft were in just too tough.

 

[Readie]

Boeing XB-38 Flying Fortress - Wikipedia, the free encyclopedia

This was another avenue explored. I read this and wondered if 4 Griffons would have been another option.

Cheers
John