MOST OVERRATED AIRCRAFT OF WWII (3 Viewers)

[gjs238]

The design originally envisioned a more powerful engine. The -5 was all that was available when production started. The -43 was not a big improvement, so the whole B-26 program was always saddled with underpowered engines. That's a factor in aircraft development. You can't use what's not available. Then once production is in full swing, its hard to make major changes.
The B-26 involved so many untried systems that its not surprising that the early versions had a lot of issues. The Curtiss Electric prop was notorious for failing at high power.
The biggest problem was the flood of inexperienced pilots stuffed into them right out of flight school.
The 22nd BG and 28th BG, manned by crews trained prewar that flew them in action loved them. They were fast enough to outrun Zeroes, something the B-25 could not do.
The 22nd lost only a handful to fighters while flying the B-26, never more than one on a given mission, the 3rd BG flying B-25s at the same time lost five on one mission alone.

Interesting.
Did the B-26 design envision a more powerful R-2800, or a different engine?

 

[GrauGeist]

The Douglas A-26 (clean) could outrun an A6M, the Martin B-26 could not.

 

[Shortround6]

It may depend on altitude. The Lockheed PV-1 could outrun some Japanese fighters but only at low altitude.
It may also depend on the A6M.
It may also depend on the weight of of the B-26/A
The engines used in these aircraft would only hold Military power ( the 1850hp) to about 2700ft (no ram) the alter 2000hp engines would only hold the 2000hp to 1500ft. getting caught at 7-8000ft would mean several hundred hp less.
In one test on a B-26A it was able to do 285mph at 5000ft using only 1350hp per engine (2400rpm), test was on a wing profile modification which may no difference to high speeds. It also made no difference to stall and so was dropped.
The B-26A had a single .30 cal out the nose, the two gun top turret and a single .50 out the back, no chin guns and one, 30 cal gun firing out the belly. Nose .30 was often replaced by a .50 but these early B-26s were a lot lighter than than the later ones.
With bombs gone and a fair amount of the fuel burned off they may have been able to outrun the A6M2 with its single speed supercharger at low altitude. The A6M3 with two speed supercharger may have been a different story as it picked up 150-180hp (?)at low altitude.

 

[Hiromachi]

Those things are relative, a bomber after bombing run is much lighter and pilots put their machines in a small descent to get away as quick as possible. That of course adds to the current airspeed and may prevent scrambling fighters from intercepting. On the other situation, Zeros may have no issue with catching B-26 if they are high above and could trade altitude for speed.

 

[tomo pauk]

Vis the R-2800, The -5 was the initial production model of the R-2800. About 1450 were produced. The -5 production was slated to equip the B-26 program, but did not produce the promised power output. ....

The design originally envisioned a more powerful engine. The -5 was all that was available when production started. The -43 was not a big improvement, so the whole B-26 program was always saddled with underpowered engines.
...

Thank you for the input.
I'd kindly ask for sources for the bolded part of your posts, however.

 

[Shortround6]

From Joe Baugher's web site.
" On March 11, 1939, the Air Corps issued Proposal No. 39-640 for the design of a new medium bomber. According to the requirements listed in the specification, a bombload of 3000 pounds was to be carried over a range of 2000 miles at a top speed of over 300 mph and at a service ceiling exceeding 20,000 feet. The crew was to be five and armament was to consist of four 0.30-inch machine guns. The proposal called for either the Pratt & Whitney R-2800, the Wright R-2600, or the Wright R-3350 radial engine."

Now please note that the R-2800 had not yet flown in a test hack and it took until May of 1940 for the 5th R-3350 to be accepted.

"Proposals were received from Martin, Douglas, Stearman, and North American."
"Detailed design of the Model 179 was completed by June of 1939. On July 5, 1939, the Model 179 was submitted to a Wright Field Board. The Martin design was rated the highest of those submitted, and on August 10, 1939, the Army issued a contract for 201 Model 179s under the designation B-26. This contract was finally approved on September 10."

Also "The engines were to be a pair of 1850 hp Pratt & Whitney R-2800-5 Double Wasp air-cooled radials, which were the most powerful engines available at the time."

As it turns out, even though Wright started first on the R-3350 vs the R-2800 it was put on the back burner while they sorted out the R-2600 so that P & W caught up fairly well at this time. Due to the time delay and Wright changing head designers and Wright diverting into the R-2160 Tornado program the R-3350 fell so far behind that it required a total redesign before being used in the B-29.
In the Spring/Summer of 1939 the R-2800 may very well have been the most powerful engine that looked likely to make it into production first.
If comparing the R-2800-5 to the R-3350 make sure to compare to the early R-3350 that was actually only flown in the B-19 and a few other experimental aircraft.
I would also note that P & W only started design work on the "B" series R-2800 of 2000hp in MAY 1940.

 

[BLine22]

The 2800-5 engines were rated at 1850hp and the -43 at 2000hp. The R-2600-92 on the B-25H rated at 1700hp. MTOW of 37k and 35k respectively. I wouldn't consider the B-26 to be underpowered having a power to weight ration similar to A-26 and PV-1.

 

[Conslaw]

IMHO, it's really hard coming up with a most overrated aircraft of World War II, especially in the context of this board. If nothing else, the strengths and weaknesses of each type are well-discussed in this forum, so I think the B-26 and other aircraft are rated accurately. It is easier coming up with an "underachieving" aircraft. The two leading contenders for me would be the A-26 Invader, which should have been THE standout medium bomber of the war, but was so delayed getting into combat that its effect was negligible (despite first flying in 1941). It showed its capabilities in Korea and Viet Nam. The second candidate for under achiever would be the P-61 Black Widow. The reason for the P-61's underachievement is a combination of its high development costs and its limited availability in combat zones truly under threat. When it did get into combat zones, it often wasn't supported by ground radar assets suitable for getting it into intercept position.

 

[GregP]

The Martin B-26 Marauder wound up as a safe medium bomber in USAAF service, so perhaps speed wasn't everything. They called it the "Baltimore Whore" due to small wings (no visible means of support) and the widow maker, but all that really happened is the pilots learned how to fly it in landing configuration so 90 mph on final didn't seem way too fast. Bad safety record at the start of service and a pretty good one by the time it was retired (loss per sortie at 0.0070 --- the BEST loss per sortie was the A-26 Invader at 0.0058, but it flew less than half of the sorties the B-26 did).

 

[Peter Gunn]

The Martin B-26 Marauder wound up as a safe medium bomber in USAAF service, so perhaps speed wasn't everything. They called it the "Baltimore Whore" due to small wings (no visible means of support) and the widow maker, but all that really happened is the pilots learned how to fly it in landing configuration so 90 mph on final didn't seem way too fast. Bad safety record at the start of service and a pretty good one by the time it was retired (loss per sortie at 0.0070 --- the BEST loss per sortie was the A-26 Invader at 0.0058, but it flew less than half of the sorties the B-26 did).

"A Marauder a day in Tampa Bay"

 

[fastmongrel]

so 90 mph on final didn't seem way too fast.

Wasnt the safe landing speed more like 140mph. Imagine coming from your little 600hp Beechcraft or Cessna trainer that would land at 60mph and getting into a 4,000hp fire breathing monster like the Marauder.

 

[gjs238]

Wasnt the safe landing speed more like 140mph. Imagine coming from your little 600hp Beechcraft or Cessna trainer that would land at 60mph and getting into a 4,000hp fire breathing monster like the Marauder.

It was a ruthless plane to fly...

 

[Greg Boeser]

William Wolf, B-26 Marauder, the Ultimate Look, is a good synopsis on the development of the B-26. Martin had proposed designs with several different engines, unsupercharged and supercharged R-2600s, unsupercharged and supercharged R-2800s and R-3350s. The Army selected the version with the unsupercharged R-2800s. This is the design that beat out the North American entry by 150 points.
Hindsight being 20/20, its clear that the B-25 turned out to be the better investment. The B-25 proved more versatile, cheaper and easier to build and maintain, easier to fly.
The A-26 was a whole generation later.

 

[GregP]

About the speed in final ... my mistake, it was about 150 mph. Duuhhhh ....

 

[tomo pauk]

William Wolf, B-26 Marauder, the Ultimate Look, is a good synopsis on the development of the B-26. Martin had proposed designs with several different engines, unsupercharged and supercharged R-2600s, unsupercharged and supercharged R-2800s and R-3350s. The Army selected the version with the unsupercharged R-2800s. This is the design that beat out the North American entry by 150 points.
Hindsight being 20/20, its clear that the B-25 turned out to be the better investment. The B-25 proved more versatile, cheaper and easier to build and maintain, easier to fly.
The A-26 was a whole generation later.

Good points, but the bolded part.
Nobody was flying military aircraft with unsupercharged engines from early 1930s on. Americans even used supercharged engines on their tanks.

 

[wuzak]

Good points, but the bolded part.
Nobody was flying military aircraft with unsupercharged engines from early 1930s on. Americans even used supercharged engines on their tanks.

I guess that means with a turbo.

 

[Greg Boeser]

Right.
Martin expected turbocharged R-2800s or R-3350s would push the B-26's top speed to 368 to 400 mph.

 

[Shortround6]

In this case I believe the terms supercharged and unsupercharged refer to being turbo-charged. The turbo R-2600 never did work out and the Turbo R-3350 took a long time to get service ready.

I believe the superchargers on the radial engines used in some US tanks were geared low enough that they were little more than "mixing fans" that assured an even mixture distribution to all the cylnders.

 

[BLine22]

I wouldn't say the B-25 was a better investment. The B-26 had an excellent combat record in the ETO. USAAF didn't deploy B-25s to the ETO, they were used in the Pacific, Mediterranean and sent to USSR via lend-lease. Neither aircraft served a frontline role after the war but the Mitchell served as a trainer and other secondary roles because of its better flying characteristics.

B-25 vs B-26 could be a separate thread.

 

[GrauGeist]

The B-25 did see some action in southern Europe with the USAAF, but it was also operated by the RAF as the Mitchell and saw extensive use from 22 January 1943 onwards. After D-Day, the RAF kept their Mitchells at forward bases in France and Belgium.