Most 'Underrated' Aircraft of WW2?

[davparlr]

Some other things were going on between the early short wings and the later aircraft. The early ones had spinners on the props, the air intakes were smaller (no sand filters) the oil cooler intake at the bottom of the cowl was smaller, the tail gun position may have had less drag (when closed)

For my comparison, I used the data (combined from the two books) for the B-26B-2 (short wing) and the B-26B-10/B-25C-5 (long wing). The B-26B-2 had already deleted the spinners. The difference between the two B-26s were an increase of empty weight from 22,380 lbs to 24,000 lbs, the majority of the weight has to be in the wing extensions. Various electronics, some winterizing, auto ejecting life raft, and extended nose wheel was included in growth number. (Empty weight seems to be a variable, however AHT, in its weight list for the P-61, does not use machine gun or cannon weight in the empty weight value only fixtures.) 50 cal machine guns went from six to ten. Other changes affecting performance was the addition of larger air scoops and two machine guns were packaged on the side of the aircraft. Top speed of the B-26B-2 was 317 mph and the cruising speed was 260 mph whereas the B-26B-10 had a top speed of 282 mph and a cruising speed of 214 mph (B-26C-5, same specification numbers as the B-26B-10).

However the weight chart shows a normal gross weight of 28,706lbs.

This Normal gross is for 465 gallons of fuel and 2086lb of bombs.

Armament is one .30 cal in the nose, one .30 cal in the tunnel, the two .50 cal in the top turret and a single .50 in the tail. Each .50 has 200 rounds. The .30s have 600 rounds each. There is only a 5 man crew. Turret gunner mans the tunnel gun?

For the B-26B, the normal gross weight is 29,725 lbs. All the machine guns are 50 cal. I don't have crew data but I would suspect that the B-26B-2 would have one less crew member than the B-26B-10 which had seven. The B-26B-10 did have two side gun stations which the -2 didn't have, but no ventral position which the -2 did have.

A short wing with the twin .50s in the tail, one or more .50s in the waist/bottom positions, and a .50 in the nose is going to pick a fair amount of weight (forget the cheek guns that come later) and that is part of the 1500lb increase, not just the weight of the bigger wing.

Carrying more than four 500lb bombs is going to affect things. and it could easily carry more.

filling (or trying to run) with fuel in the outer wing tanks is going to add weight

I would guess that the growth of empty weight, 1620 lbs, is pretty close to the weight of the wing extension change. The other equipment are bits and bobs. Even the machine gun installations were not sophisticated. Just thumb-nailing it I would estimate that if the B-26B-2 was loaded up to the level of the B-26-10/B-26C-5, the top speed of the B-26B-2 would be around 300 mph and the cruise speed would be around 240 mph. For a 300 mile penetration into France that would provide 20 minutes less time to be exposed to enemy defenses. I think, for that environment, 20 minutes is literally a lifetime. Speed is life.

As far as problems of weight distribution I would guess many aircraft had problems with weight distribution, even now. I working on the Tacit Blue aircraft in the early 80s and was responsible for most of the avionics. We were continually pressed to lower our weight on every component, which was usually a few pounds. After all that work, one ton of lead was added to meet cg requirements!

 

[Conslaw]

Great info, Shortround. Only 465 gallons of fuel in an early B-26? WOW, the P47N carried more than that with a bit heavier bombload. Now, I realize that I'm comparing a 1945 fighter with a 1941 bomber, but still, that seems like a tiny amount of fuel for a plane that large and powerful. I was also in the camp that the B-26 should have stuck with the short wings, but now Im not so sure. An aggravating factor is that the Martin B-26 should have been phased out in favor of the Douglas A-26 starting in early 1944, but the Army's indecision on design changes to the A-26 slowed its introduction. I think the A-26 is the largest underachiever among American planes in WW2, but only because the plane had so much potential.

Some other things were going on between the early short wings and the later aircraft. The early ones had spinners on the props, the air intakes were smaller (no sand filters) the oil cooler intake at the bottom of the cowl was smaller, the tail gun position may have had less drag (when closed)
View attachment 502773

From the pilots manual the speeds of 326mph or 323mph were obtained at 26,734lbs.
However the weight chart shows a normal gross weight of 28,706lbs.
This Normal gross is for 465 gallons of fuel and 2086lb of bombs.
Armament is one .30 cal in the nose, one .30 cal in the tunnel, the two .50 cal in the top turret and a single .50 in the tail. Each .50 has 200 rounds. The .30s have 600 rounds each. There is only a 5 man crew. Turret gunner mans the tunnel gun?

The speed figures are either for bombs gone or only about 130 gallons of fuel left in the tanks.

A short wing with the twin .50s in the tail, one or more .50s in the waist/bottom positions, and a .50 in the nose is going to pick a fair amount of weight (forget the cheek guns that come later) and that is part of the 1500lb increase, not just the weight of the bigger wing.
Carrying more than four 500lb bombs is going to affect things. and it could easily carry more.
filling (or trying to run) with fuel in the outer wing tanks is going to add weight.

The Big wing gets a lot of blame but the 323mph figure and the cruise speeds that go with it were obtained at a weight that was thousands of pounds below the way the plane wound up being operated.
The early planes were a bit sensitive to weight distribution. With bombs and ammo gone and less than 250 gallons in the tanks ( it took off with only 465 gal) it was recommended in the manual for two of the crew members from the pilots and/or navigator stations to move to seats in the turret compartment to help get the CG in trim for ease of control when landing. maybe increasing the weight of the rear guns solved that?

 

[Shortround6]

Great info, Shortround. Only 465 gallons of fuel in an early B-26? WOW, the P47N carried more than that with a bit heavier bombload. Now, I realize that I'm comparing a 1945 fighter with a 1941 bomber, but still, that seems like a tiny amount of fuel for a plane that large and powerful. I was also in the camp that the B-26 should have stuck with the short wings, but now Im not so sure. An aggravating factor is that the Martin B-26 should have been phased out in favor of the Douglas A-26 starting in early 1944, but the Army's indecision on design changes to the A-26 slowed its introduction. I think the A-26 is the largest underachiever among American planes in WW2, but only because the plane had so much potential.

I am sorry if a gave a wrong impression. The early short wing could hold a lot more fuel 962 gallons in the standard wing tanks (934 usable) . It is just that the speed (and altitude ?) figures usually quoted are for a much lighter airplane.

see: http://www.wwiiaircraftperformance.org/B-26/B-26_Operation_and_Flight_Instructions.pdf

If the service ceiling was 25,000ft at 26,734lbs what was the ceiling when the plane weighed 30,000lbs or more?
Max loaded was 33,326lbs.

There is a lot written about how the big wing slowed the plane down but nowhere near as much is written about how the unrealistic performance figures give a false impression.

 

[davparlr]

After reviewing multiple flight test data for the B-26 in various configurations trying to normalize the variables, which is always difficult, the results is a bit conflicting. This seems to be the closest test set

Test at approx. 5k ft.

B-26B-2, AC 41-17756, airspeed 281 mph, 1400 hp/eng (mil ?), test weight 29,860 lbs

B-26B-10, AC 41-18199, airspeed 250 mph, 1400 hp/engine est. (test-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.

The B-26B-10 configuration contained the torpedo rack which would impact airspeed. The P-51 had two wing racks for bombs and these impacted the top speed by 10 mph at 400 mph at 5000ft. I would suspect the single torpedo rack impacting the B-26 at 250 mph as around 5 mph. From pictures, the torpedo rack seems to be a clean installation.

There is an unknown impact of cowl flaps and oil cooler on the B-26B-10.

I previously discussed the basic configuration differences between the B-2 and the B-10.

With this information, it appears that the short wing B-26B-2 compared to the extended wing B-26B-10, is around 20 mph faster at 5000ft, mil power (around 1400 hp/eng), and equivalent weight , which basically reflects a cleaner aircraft.

Flight test of the B-26F shows more of a compatibility to the B-26B-2 performance than it does the B-26B-10/C. It did have a 3.5 degree increase in wing incidence angle which gave it a more level cruising attitude, which I guess, made up the difference.

 

[Venturi]

Ultimately, a fast bomber was only truly advantageous against enemies which were sub-400mph. And here I'm talking about pre 1942 European aircraft, or really before 1944 for the Japanese. When a fighter has a 100+mph advantage over the bomber, air supremacy or failing that, effective fighter escort are what protect the bombers - not speed. The fast bomber ideology only really became effective when you started talking about bombing from very high up (B-29) and fast, or when the bombers had near speed-parity with the fighters (aka 1942 low-level bombing, PTO). You'll see this reflected in the bomber design as the war went on: medium bombers were no longer "the bomber will always get through", regardless of their speed (if the fighters were sufficiently faster). Thus faster designs were less prioritized than those which carried more payload - or had longer ranges. Or they were simply modified to achieve those goals (as in the case of the short vs long wing B26). The experiences in the Med showed that plainly enough, where the Luftwaffe medium bomber fleet was decimated... A major exception was the Mosquito - and Arado - but again, we are talking now about bombers with near (or greater) speeds than the pursuing aircraft.

 

[Kevin J]

Alot of good information but don't you think as p39 expert said if they had the 2 stage Allison in production by April 43 and they new that it was commimg it doesn't seem like to much of a jump to think they could have had the q delivered by spring pf 44.

The only problem with all this is 'who's the customer'? The Aussies don't need them, they have the Spitfire VIII. The Kiwis don't need them, they have the Corsair. The Brits are using their Warhawks as fighter bombers so they don't need the high altitude capability. The USAAF has got better planes like the Mustang and Thunderbolt. The VVS prefers the Cobra because its faster. The only possible customer I see is Soviet Naval Aviation who preferred the Warhawk over the Cobra because of its greater range. So there you have it, only one potential customer for a plane that may not even be ready for service before the European War is over.

 

[P-39 Expert]

The only problem with all this is 'who's the customer'? The Aussies don't need them, they have the Spitfire VIII. The Kiwis don't need them, they have the Corsair. The Brits are using their Warhawks as fighter bombers so they don't need the high altitude capability. The USAAF has got better planes like the Mustang and Thunderbolt. The VVS prefers the Cobra because its faster. The only possible customer I see is Soviet Naval Aviation who preferred the Warhawk over the Cobra because of its greater range. So there you have it, only one potential customer for a plane that may not even be ready for service before the European War is over.

Lots of customers for a high altitude fighter, problem was, we didn't want the Russians to have them. Fine to give (lend lease) them single stage P-39s and P-40s but not something that could easily fight at B-17/B-24 altitudes. The Russians were our allies and we wanted to help them, just not too much.

Perfect outcome for the war (for us) would have been if the Germans and Russians had defeated each other before D-Day.

 

[Shortround6]

Lots of customers for a high altitude fighter, problem was, we didn't want the Russians to have them. Fine to give (lend lease) them single stage P-39s and P-40s but not something that could easily fight at B-17/B-24 altitudes. The Russians were our allies and we wanted to help them, just not too much.

According to Wiki;
"A total of 2,397 (2,672, according to other sources)[13] such aircraft were delivered to USSR, out of the overall 3,303 production aircraft (72.6%).[14]"

Deliveries of two stage "high altitude"P-63s to Russia.


and we have the problem that the two stage Allison in the spring of 1943 really wasn't that good of a high altitude engine.

 

[Kevin J]

Lots of customers for a high altitude fighter, problem was, we didn't want the Russians to have them. Fine to give (lend lease) them single stage P-39s and P-40s but not something that could easily fight at B-17/B-24 altitudes. The Russians were our allies and we wanted to help them, just not too much.

Perfect outcome for the war (for us) would have been if the Germans and Russians had defeated each other before D-Day.

The Russians were given small numbers of Thunderbolts which could attain a very high altitude, and over a thousand Spitfire LF IX's which also had a high altitude capability. I'm also thinking, so why would the Soviet Navy need a Warhawk with better altitude capability when the P-40N was perfectly adequate for the altitudes which they flew at.

 

[P-39 Expert]

According to Wiki;
"A total of 2,397 (2,672, according to other sources)[13] such aircraft were delivered to USSR, out of the overall 3,303 production aircraft (72.6%).[14]"

Deliveries of two stage "high altitude"P-63s to Russia.


and we have the problem that the two stage Allison in the spring of 1943 really wasn't that good of a high altitude engine.

The P-63 was delivered to the Russians well after the LW had been beaten and were not used in combat, unless the rumors that Pokryshkin had one (against regulations) are true.

Whether you say the V-1710 wasn't that good or not, they provided a 25% increase in HP at 25000' over a single stage model. Would have helped any P-39, P-40 and P-51A.

 

[Shortround6]

Doesn't matter when or why, you said the US didn't want the RUssians to have high altitude fighters and yet we shipped them around 3,000 (counting a few hundred P-47s) so, obviously , we did want them to have them.
This also pretty much makes hash out of the idea that we didn't want them to have aircraft that would operate at the hights the B-17 and B-24 would operate at.

The 25% increase in power came at the cost of several hundred pounds of engine weight (and even more weight for the complete powerplant) and would require some significant redesign of the aircraft in question, meaning a delay in getting them into production and delivering them to the "other customers".

The _93 Allison was not fully sorted out and passing it's type tests until the late fall of 1943, not the spring of 1943.

 

[GrauGeist]

The Soviets were also provided various types of the P-51, either through lend-lease or abandoned.
These were the RAF Mk.I, P-51B, P-51C and P-51D, but the Soviets weren't interested in them and none of the Mustangs were used in any front line duties.

In regards to the P-47, the Soviets felt that it's attributes were already met by their IL-2 for ground attack and both the YaK-9 and La-5 for high-altitude combat, so the P-47s in their service were relegated to training or high-altitude CAP over interior cities.

 

[P-39 Expert]

Doesn't matter when or why, you said the US didn't want the RUssians to have high altitude fighters and yet we shipped them around 3,000 (counting a few hundred P-47s) so, obviously , we did want them to have them.
This also pretty much makes hash out of the idea that we didn't want them to have aircraft that would operate at the hights the B-17 and B-24 would operate at.

The 25% increase in power came at the cost of several hundred pounds of engine weight (and even more weight for the complete powerplant) and would require some significant redesign of the aircraft in question, meaning a delay in getting them into production and delivering them to the "other customers".

The _93 Allison was not fully sorted out and passing it's type tests until the late fall of 1943, not the spring of 1943.

The auxiliary stage itself weighed about 125# without carb. Any redesign should have been started to coincide with the anticipated production date of April '43. After all it had been in development since '40.

And the AAF was confident enough in it passing the tests that it put it into the P-63 prior to passing. It was a reliable engine. And it pushed a P-63 that was heavier than a P-39 with a larger wing to 420+mph at high altitude.

 

[Shortround6]

Ok the engine weighed 125lbs more,but the engine is positioned further forward in either the P-40 or P-51 airframes due to the longer length and that affects the center of gravity, even shifting the engine only a few inches forward and modifying the area behind the engine will call for some serious redesign. The two stage Allison was far from a drop in replacement for the single stage engine. Now I assume that with no more weight allowed for in your plans you are going to keep using the same propellers as the single stage allisons? The same radiators and oil coolers despite the much increased heat loads? No water injection system to act as crutch due to the lack of intercoolers?

I like the "started to coincide with the anticipated production date of April '43. After all it had been in development since '40."

The Continental IV-1430 had been in development since about 1932-33 and the Army was still hoping it could be turned into a useable engine in 1943.

Lets look at a few of the P-63 benchmarks to see how practical this scheme is.

The XP-63A makes it first flight April 26th 1943.
The Army formally accepts the XP-63 in May of 1943.
Production deliveries of the P-63A start in Oct of 1943.
May 16th 1944 has a report on operational suitability of the P-63A conclude that the aircraft in it's current form cannot be considered an operationally suitable front line fighter.
Aug 1944 has the USAAF with 339 P-63As on hand, How many have already been sent to the Russians I don't know.

The -93 engine was 100-200hp behind the two stage Merlin in the low 20,000ft altitude range in early/mid 1943.

 

[GrauGeist]

If memory serves right, the Soviets sent a test pilot and an engineer to Bell early in '44 to evaluate the A type and uncovered a handfull of bugs, it was with their input that the '63 was greatly improved.

 

[davparlr]

Ultimately, a fast bomber was only truly advantageous against enemies which were sub-400mph. And here I'm talking about pre 1942 European aircraft, or really before 1944 for the Japanese. When a fighter has a 100+mph advantage over the bomber, air supremacy or failing that, effective fighter escort are what protect the bombers - not speed. The fast bomber ideology only really became effective when you started talking about bombing from very high up (B-29) and fast, or when the bombers had near speed-parity with the fighters (aka 1942 low-level bombing, PTO). You'll see this reflected in the bomber design as the war went on: medium bombers were no longer "the bomber will always get through", regardless of their speed (if the fighters were sufficiently faster). Thus faster designs were less prioritized than those which carried more payload - or had longer ranges. Or they were simply modified to achieve those goals (as in the case of the short vs long wing B26). The experiences in the Med showed that plainly enough, where the Luftwaffe medium bomber fleet was decimated... A major exception was the Mosquito - and Arado - but again, we are talking now about bombers with near (or greater) speeds than the pursuing aircraft.

Actually, there are other factors associated with surviving a military strike where where even small increases in speed are important. One of these is exposure time to enemy defenses, ten, fifteen, twenty minutes reduction in exposure to enemy defenses can significantly improve strike suvivability. Another is the reduction of enemy response time. Faster attackers complicate and reduce enemies response time to confront threat. AAA targeting is more complicated. It is more difficult to target faster aircraft than a slower one. Even small increases of fighter overtake time is important. Point interceptor fighters generally held a limited amount of fuel and every minute of max power gobbled up fuel. The Bf 109 only carried 105 gallons of fuel internally and 1500 hp max engine was a hungry beast. There is a good reason for the comment speed is life

I written about this before but the four short winged B-26s, with mounted torpedoes, were considered "blazing fast and difficult to bring down" by the Japanese. Three of the four reached weapon release point with one flying down the Akagi's flight deck machine gunning the ship. Two made it back, well shot up. Had those AAF pilots been better trained in torpedo attacks or had Navy torpedo bomber pilots, and, and this is a big and, had they carried Japanese aerial torpedoes, great damage could have been done to the Japanese invasion fleet.

 

[GrauGeist]

I know the B-26 torpedo idea was noble, but they may have had a better chance for results with skip-bombing.

Of course, this is purely hind-sight.

 

[wuzak]

Lots of customers for a high altitude fighter, problem was, we didn't want the Russians to have them. Fine to give (lend lease) them single stage P-39s and P-40s but not something that could easily fight at B-17/B-24 altitudes. The Russians were our allies and we wanted to help them, just not too much.

Perfect outcome for the war (for us) would have been if the Germans and Russians had defeated each other before D-Day.

Did the Soviets want high altitude fighters?

The USSR had the MiG-3 in 1941/42, but these were gradually phased out of front line service, as they didn't see much high altitude fighting, and they were poor at low altitude.

 

[Shortround6]

Did the Soviets want high altitude fighters?

The USSR had the MiG-3 in 1941/42, but these were gradually phased out of front line service, as they didn't see much high altitude fighting, and they were poor at low altitude.

They also needed the engine production capacity for the AM-38 engine in the IL-2.
Same basic engine, every Mig-3 built was an IL-2 without an engine.

 

[DBII]

My vote is the B18. Long rang and large bomb bay. Perfect for low and slow anti sub patrol. Plenty of room for the crew.