Fast bomber for USAAC: how would've you done it?

[tomo pauk]

...or faster than real ones anyway

Please toss in you proposals, for a light/medium/heavy bomber that could be conceived between 1939-1942(from proposal to deployment; 1941 as a deadline is fine also, if judged posible), using engines armament (if any?) available for USAAC back then.

 

[syscom3]

I think the A-26 was the apex of what a two engine medium bomber should have been.

In a nod tot he 5th AF, I would have placed the cockpit further forward (through a fuselage plug) for improved visibility.

 

[fastmongrel]

A 2 seat unarmed bomber using the wings and engines of the P 38. A US Mosquito equivalent with a similar sized internal bomb bay.

 

[BombTaxi]

The 'Mosquito' equivalent would be the best route - but I can't see the US going for that kind of machine, as they placed an emphasis on bombers with substantial defensive armament providing mutual support through close formations and heavy firepower. Also, the P-38 could only lift 2000lb, IIRC. If you add a larger airframe and another crew member, then increase the bombload to the Mossies 4000lb, you will lose so much performance that you're going to need guns, IMHO

 

[davparlr]

I love the Mosquito, but I don't think the US has the engines to pull it off. Also, the wood would be problematic for deployment maintenance.

A-20 was a bit too slow and the A-26 would have been a problem for the R-2800 engine, especially since it would now be used for a light weight fighter!

Okay, how about this for out of the box thinking. I'd build an XB-42 with two turbo-supercharged V-1710-27/-29 engines. I would have to ponder speed vs. range/payload trade-offs.

 

[syscom3]

The A-26 used the R2800. Did you mean a different engine?

 

[wuzak]

I believe he is saying that with Tomo's lightweight R-2800 fighter coming on-stream at about the same time the supply of R-2800s is going to be stretched thin, and could cause problems for the production of the A-26.

Which, I suppose, could be solved by dumping the B-26 in favour of the B-25, thus freeing up the R-2800 for the A-26.

 

[wuzak]

...or faster than real ones anyway

Please toss in you proposals, for a light/medium/heavy bomber that could be conceived between 1939-1942(from proposal to deployment; 1941 as a deadline is fine also, if judged posible), using engines armament (if any?) available for USAAC back then.

What is meant by conceived? As in drew up a proposal and submitted it to the USAAC/F for their perusal? Or do you mean it gets through the process to the construction of a prototype, or even to production?

This what-if has a few timeline issues.
a) If it is merely conceived by 1942 then it is unlikely to get into volume production by war's end. The A-26 prototype construction was authorised in mid 1941, flying in mid 1942 and seeing combat in mid 1944. The project could suffer serious delays due to priority for production of existing typres.

b) Anything conceived before mid 1943 will not benefit from the realisation that the self defending bomber is a myth. Thus the AAC is unlikely to approve a lightly defended bomber. At best you will get approval for a replacement/supplement to the A-20/B-25/B-26 bombers - as was the case with the A-26.

c) Anything conceived before 1941 will not benefit from the demonstration of the Mosquito's performance. Unless the designer got his/her hands on the 1937 memorandum by George Volkert (Handley Page's chief designer), A Memorandum on Bombing Policy and its Influence on design, which proposed a high speed unarmed bomber as being a better solution than a heavily defended bomber. Volkert's hypothetical design, drawn to specification P.13/36 (which produced the Manchester and Halifax), had an estimated top speed of 380mph on 2 x 2000hp Vultures with a normal bomb load of 3000lb and a maximum of 7000lb. That sort of bomb load would make the USAAC/F brass happier than the Mossie's original 1000lb bomb load. You'd still have to get it past the bomber barons, though.


I suppose that the B-17 as originally conceived was a fast bomber, the prototype being faster than any of the USAAC's persuits at the time.

 

[wuzak]

A 2 seat unarmed bomber using the wings and engines of the P 38. A US Mosquito equivalent with a similar sized internal bomb bay.

Maybe better based on the P-61?

Use turbocharged R-2800s, which weren't used on P-61s until the post WW2 P-61C, ditch the turret and belly guns, maybe use the one piece canopy from the P-61E/F-15 Reporter, equip the backseater with a telescopic bomb sight (so he doesn't have to be in the nose). Bomb bay could go under the fuselage where the 4 x 20mm cannons were, with additional stores/fuel tanks on underwing pylons. Maybe have to move cockpit forward to allow for the bomb bay, or shorten the cockpit area.

The night fighter version could use the same canopy, with the radar in the nose and 4 x 20s in the belly. The bomber version may have room for some guns in the nose - maybe 4 x 0.50s?

http://3.bp.blogspot.com/_8DAL7gPYBiM/TQRGgubjqNI/AAAAAAAAAp8/m9pxotVML-Q/s1600/F15_Reporter.jpg
http://i792.photobucket.com/albums/yy210/Ryan_Crierie/Northrop_F-15_Reporter_10.jpg
http://airspot.ru/catalogue_image/filename/5412/thumb/p61e-i.jpg
http://fc07.deviantart.net/fs47/i/2009/196/e/4/F_15A_Reporter_Lineart_by_talos56.jpg

Still not going to get this before mid 1944.

 

[davebender]

The A26 entered service during mid 1944 with a max speed of about 355mph. 1,400 mile range with 2,000lb internal bomb load. IMO that's not terribly impressive for a late war medium bomber. It was no faster then the B29 heavy bomber which entered service about the same time.

Ju-288A. 416mph max speed. 2,237 miles with 3,000kg internal bomb load.
IMO something like this should be the objective. Very fast, excellent range and decent internal bomb load. Did the U.S. produce a prototype of anything similiar? Perhaps it could be powered by a pair of 2,500hp Packard built Napier Sabre engines.

 

[wuzak]

btw, the USAAC/F saw the DB-7/A-20 as being too lightly armoured. For its day it was a reasonably high performance bomber.

Engine wise, in the time period I don't think there is any other option for the US than the R-2800. There were a lot of experimental 2000hp+ motors, but the R-2800 was the only one going to be available in the required time frame. I suppose the R-3350 could also be considered, but it was a bit behind the R-2800 in development.

The other realsitic alternative was the V-3420, which was developed using V-1710 parts. If it was required for a high speed bomber then maybe its development would have received a higher priority earlier.

 

[wuzak]

The A26 entered service during mid 1944 with a max speed of about 355mph. 1,400 mile range with 2,000lb internal bomb load. IMO that's not terribly impressive for a late war medium bomber. It was no faster then the B29 heavy bomber which entered service about the same time.

Ju-288A. 416mph max speed. 2,237 miles with 3,000kg internal bomb load.
IMO something like this should be the objective. Very fast, excellent range and decent internal bomb load. Did the U.S. produce a prototype of anything similiar? Perhaps it could be powered by a pair of 2,500hp Packard built Napier Sabre engines.

Douglas A-26 Invader - Wikipedia, the free encyclopedia has the internal load as 4000lb with 2000lb external load possible. The internal load is probably due to space restrictions. Lose the defensive armament, fit high altitude versions of the engine, such as the R-2800-8 used in the F4U-1, F6F and P-61A/B and the performace would no doubt improve.

 

[Shortround6]

The A26 entered service during mid 1944 with a max speed of about 355mph. 1,400 mile range with 2,000lb internal bomb load. IMO that's not terribly impressive for a late war medium bomber. It was no faster then the B29 heavy bomber which entered service about the same time.

True but it was certainly much more reliable than the 1944 B-29, much less likely to set itself on fire. What was the range with a 4000lb internal bomb load?

Ju-288A. 416mph max speed. 2,237 miles with 3,000kg internal bomb load.

At least the B-26 could actually meet the performance numbers given for it, Not the numbers given in the manufacturers advertising literature before the plane flew.

IMO something like this should be the objective. Very fast, excellent range and decent internal bomb load. Did the U.S. produce a prototype of anything similiar? Perhaps it could be powered by a pair of 2,500hp Packard built Napier Sabre engines.

400mph, 3 tons of bombs and almost intercontinental range are fine goals for a medium bomber. They just took a while to achieve.

 

[Shortround6]

If the dead line is Jan 1942 for squadron service for actual operational use in the Spring/summer of 1942 the US has a choice of three engines. the Wright R-2600, the P&W R-2800 and the Allison V-1710.

If we are talking about a light/medium bomber then choices are going to start falling to sort of a cross between an A-20 and B-25 using the R-2600. The A-20 couldn't carry enough fuel to be as useful as a slightly bigger plane and cutting one crew member and a few .30cal guns isn't going to provide it. That leaves a cut down B-25 type. The Early ones without power turrets could hit 322mph. Cutting crew means less armor needed and cutting the few hand aimed defensive guns means a bit more weight saving but we are talking in the range of 1,000-2,000lbs here. A bit smaller wing but if you want 4000lbs of bombs and over 700 gallons of fuel (4200lbs) you can't go too small on the wing without winding up with a slightly smaller B-26.

The B-26 could carry 962 gallons of fuel not including bomb bay tanks. And it needed them. From Joe B's web site. "Range 1150 miles at 214 mph with 3000 lbs of bombs and 962 gallons of fuel".

If you want speed you are going to need even more fuel. Granted you can ditch a few crew members and those .50 cal guns and a smaller fuselage will help a bit but those big radials have a lot of drag.

A cross channel dash is one thing but South Pacific distances are another.

Carrying 4,000lbs 2-300 miles at 300mph might be doable. Carrying 4,000lbs 1000miles at 300mph may not be.

 

[wuzak]

What about a 4 x turbo V-1710 aircraft, smaller than a B-17, but larger than one of the mid-sized bombers, no turrets or gunners, close attention to drag reduction?

Or, perhaps, the same 4 x V-1710s, but with pairs installed in a single nacelle on each wing. Each of the V-1710s drives its own 3 blade prop, in a contraprop arrangement. The V-1710s monted close together, almost like a V-3420.

 

[riacrato]

1. P-38 with redesigned cockpit section accomodating a bombardier, and 1000 lbs internal. Gun armament reduced to a pair of M2s. Should still go ~600-620 km/h top at fth where fighter defense is not much faster if at all.

Not great but feasible and relatively easy to do.

2. DB-7B without defensive turret and ventral gun.

 

[davebender]

If we are talking about 1939 to 1942 then 2,500hp engines are out of the question.

Operational altitude will be 10,000 feet. Low enough to bomb accurately yet above effective range of light flak.

Nothing requires a fast bomber to have only 2 engines. Build the most aerodynamic airframe possible powered by 4 of the most powerful liquid cooled engines available (they have less frontal area then radial engines). Personally I'd use Packard built Merlin engines. However Allison engines should work also. In any case they will have reliable single stage superchargers. No need for turbochargers or two stage superchargers at 10,000 feet.

Internal fuel adequate for a combat radius of 600 miles while carrying a 3 ton internal bomb load. Wing mounted drop tanks might extend the combat radius further.

No manned gun turrets. A pair of streamlined remote control barbettes similiar to those on the Me-410 cover the vulnerable tail area. Other then that, speed and maneuverability are the only defense. Two man crew (pilot plus navigator / bombardier). The navigator doubles as gunner for the remote weapon barbettes.

With a crew this small they can be enclosed in an armored cocoon. A crew this small is also more expendable then a 10 man B17 aircrew.

Fuel tanks are to be self sealing. Remainder of the aircraft would be unprotected. This bomber will fly easily on 3 engines if one gets shot out. A nice feature for a combat aircraft.

 

[parsifal]

A bit out of left field, but what if the US tried to marry its higher powered engines to a foreign designed airframe. As an example, consider the aerodynamically clean French Bre 482. The protype flown in 1940 had the following characteristics

Breguet 482 B4

Type: Heavy bomber
Overall Height: 2
Crew: 4
Engine: 4 HS 12Z, each rated at 1350 hp
Fuel tank
Empty weight: 10,450 kg
Maximum takeoff weight: 14,010 kg
Wingspan: 24.09 m
Length: 18.87 m
Height: 5.6 m
Max. speed: 560 km / h 8000 m
Ceiling: 12,000 m
Range: 1200 km
Armament: 2500 kg bombs, machine gun 3 mobile, 1 mobile gun


What would have happened to an airframe like this, if it had been adapted to four engines of around 2000HP. 560 KMH is around 350 MPH.

Some images of the prototype.

 

[wuzak]

If we are talking about 1939 to 1942 then 2,500hp engines are out of the question.

Operational altitude will be 10,000 feet. Low enough to bomb accurately yet above effective range of light flak.

Nothing requires a fast bomber to have only 2 engines. Build the most aerodynamic airframe possible powered by 4 of the most powerful liquid cooled engines available (they have less frontal area then radial engines). Personally I'd use Packard built Merlin engines. However Allison engines should work also. In any case they will have reliable single stage superchargers. No need for turbochargers or two stage superchargers at 10,000 feet.

Internal fuel adequate for a combat radius of 600 miles while carrying a 3 ton internal bomb load. Wing mounted drop tanks might extend the combat radius further.

No manned gun turrets. A pair of streamlined remote control barbettes similiar to those on the Me-410 cover the vulnerable tail area. Other then that, speed and maneuverability are the only defense. Two man crew (pilot plus navigator / bombardier). The navigator doubles as gunner for the remote weapon barbettes.

With a crew this small they can be enclosed in an armored cocoon. A crew this small is also more expendable then a 10 man B17 aircrew.

Fuel tanks are to be self sealing. Remainder of the aircraft would be unprotected. This bomber will fly easily on 3 engines if one gets shot out. A nice feature for a combat aircraft.

I still don't think that 10,000ft was enough. The Manchester operated at 10,000ft often (was it because of bomb load, or the single engine operation height - I can't recall).

2000hp liquid cooled engines weren't exactly falling off the production line at the time. For Merlins and V-1710s you have to wait until late 1943/early 1944 before that is even possible. SO then you are left with the Vulture - which is about to be cancelled, the Sabre - which is far from ready, and the V-3420 which is either on again or off again depending which month you choose. Packard Merlins aren't in great supply at the time either.

I think you need 3 crew if a defensive gun, even if remote, was required. Simply because one of the most vulnerable of times was on the bom approach, where both the pilot and bomb aimer/navigtor would be fully occupied. Having a thrid crew to aim the gun on a bombing approach would be much appreciated, I'm sure.

When were reliable remote targeted barbettes possible?

I think the later Republic Rainbow showed how sleek a 4 engined aircraft could be. Make it a bit smaller, and use turbocharged V-1710s. The performance should be quite acceptable by 1942 standards.

http://www.fas.org/irp/program/collect/republic.jpg
http://fsaircraft.net/sites/default/files/models/rbw.jpg?1298020975

 

[Mustang nut]

Nothing requires a fast bomber to have only 2 engines. Build the most aerodynamic airframe possible powered by 4 of the most powerful liquid cooled engines available (they have less frontal area then radial engines). Personally I'd use Packard built Merlin engines. However Allison engines should work also. In any case they will have reliable single stage superchargers. No need for turbochargers or two stage superchargers at 10,000 feet.
No manned gun turrets. A pair of streamlined remote control barbettes similiar to those on the Me-410 cover the vulnerable tail area. Other then that, speed and maneuverability are the only defense. Two man crew (pilot plus navigator / bombardier). The navigator doubles as gunner for the remote weapon barbettes.

With a crew this small they can be enclosed in an armored cocoon. A crew this small is also more expendable then a 10 man B17 aircrew.

Dave that is starting to sound like a lancaster with the turrets removed, there was a proposal to do that but some objected on "morale" grounds. They speculated that taking the guns ammo and turrets out would give an extra 50 MPH. The lanc with no turrets and bomb load was quite an agile plane.