B25 or B26, which was the better bomber?

[Conslaw]

It looks like the US hedged its bets with virtually all aircraft types, having at least two options. On the naval side of thing this proved to be even more important than the Army. Having the F4F-3 as an alternative to the F2A-3 was crucial. Having the F6F available for carriers earlier than the F4U - crucial. Building the SBD as a stopgap before the SB2C, again crucial. In cases like the B-25 and B-26 (as well as the B-17 and B-24), both types performed well, but by producing both, we were able to get more plants online and put more people on the job. We were also able to use different engines in each, spreading the risk that if one engine type was problematic, the war effort wouldn't suffer.

I think it would be good for the F-35 to have some competition. Ideally, that competition should have been from the start, but I think it's time to start a new program, learning from mistakes made with the F-35.

(Before F4U fanboys flame me. I'm not suggesting it was a bad plane, I'm just saying that it was good that the F6F was available for carriers while the Corsair's bugs were being worked out. Having 12,000 of each was a nice luxury.)

 

[pbehn]

I would say that hedging bets is a wise strategy if you can afford the luxury. It is only in hindsight that we know how long each took to get into service. In practice they (Corsair and Hellcat) had different strengths and weaknesses which is a plus provided you have enough.

There are few "fanboys" here, however there are some real experts on aviation history.

 

[FLYBOYJ]

I think it would be good for the F-35 to have some competition. Ideally, that competition should have been from the start, but I think it's time to start a new program, learning from mistakes made with the F-35.

1 - the F-35 did have competition, it was called the X-32
2 - not to say the F-35 didn't have issues (most exaggerated) but the only new program that needs to started is a way to recycle the debris left behind after an F-35 strike (to include opposing aircraft).

Sorry to hijack the thread, we do have an F-35 thread that has up to date information on this aircraft.

"Red Flag confirmed F-35 dominance with a 20:1 kill ratio" U.S. Air Force says

 

[Madelman]

Very interesting discussion on bombers. I've learned a lot as always in this forum

But I still have a doubt, did the B-26A really need a wing increase? with the initial wing and being careful with weight increase, would have been viable to keep the B-26 faster?

Imagine that you change the training procedures to reduce crashes

 

[Shortround6]

Well, you run into two (at least) conflicting problems by keeping the weight low.
1. was defensive armament, The initial B-26 model/s weren't badly armed for 1941/early 1942 but they sure weren't well armed either. That power operated twin
.50 on top was well ahead of world standard but it only had 200rpg. The extra 200rpg fell into the overload weight catagory let alone carrying any extra. The single .50 out the tail (without power assist) also didn't have much for ammo(200rounds). As for the single .30 in the nose the the single .30 out the ventral hatch? The 5 man crew was a bit of joke too. 4 gun positions, 5 men, no co-pilot when the guns are manned?
IS the fast B-26 fast enough not to need the heavier defensive guns?
2. And this is the real heart of the matter. The B-26 only hit those high speeds when carrying a small (2000lb) bombload and not much fuel, The 326mph figure was supposed to be at 26,734 pounds.
According to the manual with 2000lb of bombs and 465 gallons of fuel the plane weighed 28,706lbs. so either the 326mph speed is good for after the bombs are dropped or you only have about 130 gallons of fuel to get home with.
With full tanks (962 gallons in the wings) and with 4000lbs of bombs weight could hit over 33,000lb on the early planes.

How they were to be used in operation I don't know but if you want to keep the high speed your bomb/range combination doesn't look a whole lot better than an A-20.
One the B-26B the tail armament installation went from 161.3 pounds to 1135.7 pounds but included 3000 rounds of ammo. Normal gross (2000lb of bombs and 465 gallons of fuel) went up 1180 lbs on the B-26B (early ones).

Once the planes get to combat zones are the commanders going to be happy with the light bomb load and short range?

 

[Greg Boeser]

The thing to remember is that the small wing area of the B-26 was based on the belief that it would be getting more powerful engines. When the USAAF formalized the contract they specified the R-2800-5 at 1850 bhp. Which was the most powerful engine available at that time. The design gross weight was 26,740 lbs, but soon operational considerations pushed the actual weight higher. The addition of a powered turret, self sealing fuel tanks and armor pushed the weight to 28,706 lbs combat weight for the early B-26 and B-26A, 29,886 lbs for the early B-26B. These numbers were the design weight based on a five man crew, 2000 lbs of bombs and 465 gallons of fuel. Take-off weight with full fuel tanks adds another 3000 lbs. Combat units in the Pacific operated with seven man crews (+400 lbs), added .30 caliber waist guns (+150 lbs) and later upgraded the .30 caliber guns to .50 caliber (+170 lbs.)
Meanwhile back in the States, the training establishment is throwing tyro pilots into them straight out of flight school and suffering astronomical crash rates. The quick answer seems to be - increase lift by increasing wing area. Weight reduction was suggested as an option by the combat units, but the Material Command was already pushing for greater increases in defensive armament and armor. By late 1942, short wing B-26Bs fitted with the slightly more powerful R-2800-41 and -43 had a gross weight 31,165 lbs, an increase of nearly 4500 lbs.
Max take-off weight was restricted to 36,500 lbs. G-load restrictions kicked in a 31,000 lbs. so at combat weight, the B-26 is already overweight.

 

[Greg Boeser]

Once the planes get to combat zones are the commanders going to be happy with the light bomb load and short range?

COMSOPAC regarded the B-26B an uneconomical plane, and felt that its role could be performed by P-38s. It should be noted that their experience was with the early R-2800-5 equipped B-26B, further weighed down by the addition of package guns.

 

[davparlr]

Well, you run into two (at least) conflicting problems by keeping the weight low.
1. was defensive armament, The initial B-26 model/s weren't badly armed for 1941/early 1942 but they sure weren't well armed either. That power operated twin
.50 on top was well ahead of world standard but it only had 200rpg. The extra 200rpg fell into the overload weight catagory let alone carrying any extra. The single .50 out the tail (without power assist) also didn't have much for ammo(200rounds). As for the single .30 in the nose the the single .30 out the ventral hatch? The 5 man crew was a bit of joke too. 4 gun positions, 5 men, no co-pilot when the guns are manned?
IS the fast B-26 fast enough not to need the heavier defensive guns?
2. And this is the real heart of the matter. The B-26 only hit those high speeds when carrying a small (2000lb) bombload and not much fuel, The 326mph figure was supposed to be at 26,734 pounds.
According to the manual with 2000lb of bombs and 465 gallons of fuel the plane weighed 28,706lbs. so either the 326mph speed is good for after the bombs are dropped or you only have about 130 gallons of fuel to get home with.
With full tanks (962 gallons in the wings) and with 4000lbs of bombs weight could hit over 33,000lb on the early planes.

How they were to be used in operation I don't know but if you want to keep the high speed your bomb/range combination doesn't look a whole lot better than an A-20.
One the B-26B the tail armament installation went from 161.3 pounds to 1135.7 pounds but included 3000 rounds of ammo. Normal gross (2000lb of bombs and 465 gallons of fuel) went up 1180 lbs on the B-26B (early ones).

Once the planes get to combat zones are the commanders going to be happy with the light bomb load and short range?

No, I do not agree. In another post, I normalized a B-26B-2 short wing with a B-26B-10 long wing, in load carrying (fuel/weapons), horsepower (1400 hp) and altitude (5000 ft) the results was that the -2 was at least 20 mph faster than the -10 according to flight test results of numbered identified aircraft. Additional equal load-outs added to both would most likely not affect this airspeed advantage. 20 mph faster cruise would give a crew 20 minutes less exposure to enemy airspace for 300 mile deep penetration strike. In addition, fighter planes would take longer to intercept and, in the process, use more precious fuel to catch, fuel they usually have little of. If you don't think 20 mph is significant, imagine driving on the interstate (we call them freeways here in California) at 70 mph and some one passes you at 90 mph. I bet at first you would say,wow that guy is really driving fast. That would represent the B-26B-2 short wing passing a B-26-10 long wing. Speed is life.

In my opinion the biggest drawback of the short wing would be the need for longer runways.

 

[Greg Boeser]

Combat comparisons of B-26s and B-25s in North Africa during the short wing era (December '42 to June '43) gave a huge advantage to the B-25. The B-26 was more maintenance intensive and the higher landing and take-off speeds resulted in more crashes. The speed differential was not considered significant because a 375 mph fighter could catch either one. The B-26 was also harder to handle on one engine. The low combat loss reputation of the B-26 did not emerge until the introduction of the long wing. Which also benefitted from better trained crews, better escort, better defined mission envelope (large formations - 24 - 36 a/c at medium altitude, heavily escorted), and weakening opposition.
Remember the loss rate for 8th AF short wing B-26Bs was .44 per sortie. OK, a bit of an exaggeration, a few short wing Bs soldiered on in the Eighth after May '43, but by resumption of operations in July, nearly all Marauders were long wing Bs and Cs.

 

[Shortround6]

No, I do not agree. In another post, I normalized a B-26B-2 short wing with a B-26B-10 long wing, in load carrying (fuel/weapons), horsepower (1400 hp) and altitude (5000 ft) the results was that the -2 was at least 20 mph faster than the -10 according to flight test results of numbered identified aircraft. Additional equal load-outs added to both would most likely not affect this airspeed advantage. 20 mph faster cruise would give a crew 20 minutes less exposure to enemy airspace for 300 mile deep penetration strike. In addition, fighter planes would take longer to intercept and, in the process, use more precious fuel to catch, fuel they usually have little of. If you don't think 20 mph is significant, imagine driving on the interstate (we call them freeways here in California) at 70 mph and some one passes you at 90 mph. I bet at first you would say,wow that guy is really driving fast. That would represent the B-26B-2 short wing passing a B-26-10 long wing. Speed is life.

In my opinion the biggest drawback of the short wing would be the need for longer runways.

My problem with this is that there were some other changes between the B-2 and the B-10. Some were subtle and some not so subtle but somehow the change in the wing gets all the credit (blame). There were a bunch of changes between the B-26/A and the B-26B-2 that also cost speed.
engine on a B-26A

original picture by Andrew Baird
Engines on a later B-26

The Spinners went away on the very early Bs. The oil cooler inlets got bigger, On the B-3s the air intakes got much bigger in order to accommodate sand filters. Now if the four package guns cost 3-5mph (or 3% of range, sources differ) what did all the changes to the engine installation cost?

[Squadron-Signal]
Please notice that the vertical stabilizer and rudder grew about 1ft 6in from the small wing to the big wing.
I haven't seen what this cost in speed and it may be lumped in the cost of the big wing.
It is said that the larger fin and rudder were needed to stabilize the bigger wing but I am at least somewhat sure that having a bigger fin and rudder helped in an engine out situation.
At some point the horizontal stabilizer and elevators got bigger too, but I don't know when.

A problem with a B-26 doing a 300 mile deep penetration strike (or even a 150 mile radius in enemy territory) is the amount of fuel required. A B-26 used 350-400 gallons an hour at max continuous depending altitude/supercharger gear and so on. Backing down to 75% power gets you (at least on the very early B-26) a cruise of just under 280mph at 8,000ft while burning around 270-290 gallons an hour. IF for instance you drop bombs at 250 miles from base and you figure 150 miles of that is enemy territory then you need about 200 gallon at bombs gone (cruise can be dropped to around 200mph and a fuel burn of close to 100gph once in friendly territory) and this means entering enemy territory with at least 350 gallons in the tanks. Now please note this takes into account NO deviations in flight path (even a several mile turn around at the target), NO reserves , Runway is lined up with the target and NO use of power above 75% even for 1 minute.

The QUestion in post #34 from a new member was

But I still have a doubt, did the B-26A really need a wing increase? with the initial wing and being careful with weight increase, would have been viable to keep the B-26 faster?

Imagine that you change the training procedures to reduce crashes

Some of the changes that slowed the B-26 down had little to do with the wing increase. While you could be a bit careful with the weight increase (did the tail gunner on the B-26B really need 1500 rounds per gun? perhaps 700-800 would have done the job? ) some was inevitable. ANd it started a spiral.

 

[Greg Boeser]

Early users of the B-26B (69th and 70th BS in South Pacific) did recommend reduction in the ammo for the rear guns. 70th BS reduced the load to 400rpg and moved the ammo canisters back to just forward of the bulkhead separating the tail gunner position from the rest of the fuselage. This was done to reduce weight and reduce the vulnerability of the feed chutes. Later, with the adoption of the M6 tail turret on the -20 blocks of the B and C, the ammo load was standardized at 800 rpg. Of course the weight of the hydraulic turret increased the tail heavy aspect of the aircraft, which led to the twisted wing on the F and G models. This increased drag and reduced top speed. But then again, trimming to correct for the tail heaviness probably was responsible for some of the speed loss in earlier models. Too bad the proposed E model modifications were not approved. Moving the top turret forward, as done with the later models of the B-25, and the installation of roll up bomb doors like on the B-24 would have improved CoG problems and reduced drag. Open bomb doors reduced speed by up to 25 mph.

 

[davparlr]

My problem with this is that there were some other changes between the B-2 and the B-10. Some were subtle and some not so subtle but somehow the change in the wing gets all the credit (blame).

Changes between the B-10 to the B-25B-2 include:
Larger cowling intakes for new engines*
Four added .50 cal machine guns- two added .50 cal to fuselage side hatches, one .50 cal added to nose, two package .50 cal added*.
Ventral .50 cal machine gun removed
Various internal mods

• automatic life raft ejector
• Day and night drift signals (?)
• Inclinometer
• Astrocompass
• Astrograph
• New Starter
• Winterization equipment (?)
• Lengthened nose wheel strut
• Mechanically operated gear doors (?)

Slotted flaps
Rudder/vertical stabilizer increase*
* Changes that affect aerodynamic performance not including wing span increase . It is my opinion that all these changes put together would have an almost imperceptible impact to the overall form drag of the B-26.
Wing span extension from 65 to 71 feet,
Empty weight increased from 22,380 lbs to 24,000 lbs, or 1600 lbs. I would guess that the non-wing extension weight increases as between 200-300 lbs (the entire tail structure of the P-47 was 250lbs) which would make the wing extension 1300-1400 lbs.

There were a bunch of changes between the B-26/A and the B-26B-2 that also cost speed.
engine on a B-26A

I was not interested in the B-26A, I was interested in two aircraft configurations that were close but with different wings in order to isolate the performance degradation of the wing extension alone. The B-26B-2, represented all the configurations prior, and the B-26B-10, which is basically the base for follow on models. And, I had flight test results of these two aircraft.

The Spinners went away on the very early Bs. The oil cooler inlets got bigger, On the B-3s the air intakes got much bigger in order to accommodate sand filters. Now if the four package guns cost 3-5mph (or 3% of range, sources differ) what did all the changes to the engine installation cost?

Neither the B-26B-2 nor the -10 tested had spinners. Also, apparently the -10 only had two package guns, per Mendenhall's Deadly Duo.

Please notice that the vertical stabilizer and rudder grew about 1ft 6in from the small wing to the big wing.
I haven't seen what this cost in speed and it may be lumped in the cost of the big wing.
It is said that the larger fin and rudder were needed to stabilize the bigger wing but I am at least somewhat sure that having a bigger fin and rudder helped in an engine out situation.
At some point the horizontal stabilizer and elevators got bigger too, but I don't know when.

Don't know much about this. I think the added size of the vertical stabilizer, or the package guns, would be very small relative to the form drag of a pretty large bomber.

A problem with a B-26 doing a 300 mile deep penetration strike (or even a 150 mile radius in enemy territory) is the amount of fuel required. A B-26 used 350-400 gallons an hour at max continuous depending altitude/supercharger gear and so on. Backing down to 75% power gets you (at least on the very early B-26) a cruise of just under 280mph at 8,000ft while burning around 270-290 gallons an hour. IF for instance you drop bombs at 250 miles from base and you figure 150 miles of that is enemy territory then you need about 200 gallon at bombs gone (cruise can be dropped to around 200mph and a fuel burn of close to 100gph once in friendly territory) and this means entering enemy territory with at least 350 gallons in the tanks. Now please note this takes into account NO deviations in flight path (even a several mile turn around at the target), NO reserves , Runway is lined up with the target and NO use of power above 75% even for 1 minute.

I don't really want to dig into this and, knowing you, I doubt if I could identify an error. However, the salient point is that the B-26B-2 has a lower drag value than the B-26B-10. Therefore, for any given mission, the B-26B-2, vs. the -10, could fly at the same speed with less power therefore use less fuel, therefore more bombload? Or could fly the same mission with the same power setting and fly faster. And since it will fly the mission faster at the same power level, it would use less fuel, therefore more bombload?

Test at approx. 5k ft.
B-26B-2, AC 41-17756, airspeed 281 mph, 1400 hp/eng,, test weight 29,860 lbs
B-26B-10, AC 41-18199, airspeed 250 mph, 1400 hp/engine est. (247mph/1325hp), wt 30,780 lbs

Notes: Since the added wing span is most likely over 1,000 lbs, the two test weights should represent identical load carry capacity.

Miscellaneous issues mentioned above, and a few others including cowl flaps have an impact on these test. Including these, I estimated the difference in airspeed at 5000 ft, 1400 hp power setting and equivalent weight to be reduced from 31 mph to 20 mph.

If any modification, e.g. electro-hydraulic tail gun, to the -10 that led to later configurations up to B-25C were applied to the -2 configuration, i.e. short wing, the results would be the same in that the -2 configuration would be faster at the same power levels just because it was just cleaner.

 

[fliger747]

As to flying the B-26, it was faster on takeoff and landing, enough so that a different frame of mind was needed. Remember that these pilots trained and transitioned from such slower aircraft. Almost like the transition to jets. I transitioned to jets from C130's which maybe had sort of B-29 weight and speeds so not so bad after a long sim program under experienced tutelage. This was war time, no such luxuries and the military aviation was very much a swim or sink proposition. In USN basic flight training of the time my father said they lost about 5% killed...

Not that it makes much difference but I did the flight dynamics for a B-26 available for Flightsim and thought it much more like approaching with a jet, at least in my interpretation. Speed is life in this case and loss of an engine on a balked landing when low and slow and cobbing the power to it for the go around is definitely a ragged edge of the envelope requiring decent skills. Low time pilots... Most of the WWII aviators could have used more and better training, a luxury and the loss rate was considered acceptable.

With good trading and experience, a good airplane, the B-26. The low loss rate speaks to this.

 

[tomo pauk]

...
With good trading and experience, a good airplane, the B-26. The low loss rate speaks to this.

Target choice, escort available - those two factors need to be factored in, too. Had nothing to do with specific aircraft, the B-26 benefitted through these. We know that un-escorted B-26 (as well as most of other bombers) will be cut to pieces when attacking in daylight, say, targets around Frankfurt area.

 

[fliger747]

The point being that they weren't crashing outlandish numbers operationally. Probably more Bf 109's bit the dust in takeoff and landing accidents than to air combat.

Speaking of Frankfurt, my co pilot (ex Edwards Test Pilot) and I were standing on a bridge in the middle of the Main and an old german galoot comes up and starts blazing away at us in german. I'm getting about half of it, all the local stuff bombed starting with the bahnhof the talks about the Amerikanish Panzers rolling into Sachenhausen. Then he blurts out "Unt das Holocaust vas ein Schwindle"....

Cheers: T

 

[tomo pauk]

The point being that they weren't crashing outlandish numbers operationally. Probably more Bf 109's bit the dust in takeoff and landing accidents than to air combat.
...

Let's not move the goal post.
Phrase 'the low loss rate speaks to this' is a world away from 'they weren't crashing outlandish numbers operationally '. Loss rate has plenty to do with enemy encountered (or not), capability of enemy Flak, targed type and distance, while operation crashes are much more related to the flying qualities of a selected A/C.

 

[davparlr]

As to flying the B-26, it was faster on takeoff and landing, enough so that a different frame of mind was needed. Remember that these pilots trained and transitioned from such slower aircraft. Almost like the transition to jets. I transitioned to jets from C130's which maybe had sort of B-29 weight and speeds so not so bad after a long sim program under experienced tutelage. This was war time, no such luxuries and the military aviation was very much a swim or sink proposition. In USN basic flight training of the time my father said they lost about 5% killed...

Not that it makes much difference but I did the flight dynamics for a B-26 available for Flightsim and thought it much more like approaching with a jet, at least in my interpretation. Speed is life in this case and loss of an engine on a balked landing when low and slow and cobbing the power to it for the go around is definitely a ragged edge of the envelope requiring decent skills. Low time pilots... Most of the WWII aviators could have used more and better training, a luxury and the loss rate was considered acceptable.

With good trading and experience, a good airplane, the B-26. The low loss rate speaks to this.

When did you transition from C-130s to jets? Back in the 50s I believe the Navy had a real problem with safety. I grew up in Pensacola where at the time the Lexington was stationed for carrier quals. It seemed like every time the Lex went out for quals it would lose a plane and pilot. I lived on the approach end of NAS runway and there were several wrecks out in the woods, mostly SNJs, one F9F. I think they started a rigorous safety program and cleaned up their act.

 

[YF12A]

My neighbor flew just about everything, including both the B-25 and the B-26. He told me the B-26 was not as easy to fly and definitely took more training to be safe in it. Said the same thing about the B-24 compared to his all time favorite, the B-17. He kept current in the B-25, among other aircraft when stationed at the Pentagon in the '50's and loved flying it and said it had better visibility as well. This is from someone with 8,500 hours in the USAAF/USAF.

 

[Greg Boeser]

That is an apt comparison. The B-24 vs B-17 and B-26 vs B-25 debates have many similarities. Both the B-24 and B-26 were more complex than their rivals, and were at least on paper better performers, but the ease of handling and easier serviceability of the B-17 and B-25 gave them an edge operationally. Accident rates were much higher for the B-24 and B-26 compared to their stable mates.

 

[Zipper730]

I guess building in an intercooler would have been harder to do even when the twin-stage superchargers became readily available for operational use in the US?