MOST OVERRATED AIRCRAFT OF WWII

[Shortround6]

In some of these offensive sweeps the "bait" aircraft were flying at fairly low level ( and in the early operations might include Blenheims)
but the "trap" aircraft flew higher in order to get the "bounce" on the German aircraft which were flying higher than the "bait" aircraft in order to both bounce them and to even see them. Operations were different but sometimes the bait aircraft were flying at 1000ft or under and trying to spot them with interceptors flying at 1000ft or under might be difficult.
It also good to remember that the very Early Allison Mustangs were not rated for War Emergency power and they didn't climb all that well even at low altitudes even though they were fast. What squadrons in the field did could vary from squadron to squadron and between the early Mustangs, the A-36s and the later Allison mustangs there were 3 different Allisons in use. The Early -39 engine used a different crankshaft and crankcase than the later ones and while it did get a WEP rating (late 1942) it was lower than the later engines.
Also remember that in North Africa, however well (or poorly) the Tomahawks and Kittihawks did against the Germans they often had a top cover of Spitfires escorting them. Germans had a choice of coming high and running into the Spitfires or coming in low and engaging the Hawks and getting out before the Spitfires arrived.

 

[stona]

And the Kittyhawks could carry bombs. From memory No. 112 Squadron was the first to operate the type in this secondary role around May 1942.
Previously in North Africa some old Hurricane Is of No 80 Squadron had been rigged to carry eight 40lb fragmentation bombs.They operated against Axis ground forces in November 1941 during Operation Crusader. The risk and losses delivering this paltry load outweighed any effect and by January the squadron had re-equipped with IICs and reverted to a fighter role.
Cheers
Steve

 

[yulzari]

And the Kittyhawks could carry bombs. From memory No. 112 Squadron was the first to operate the type in this secondary role around May 1942.

To quote from a contemporary 112 Squadron song: 'the Flying Fortress flies at forty thousand feet but it only carries a teeny weeny bomb."

 

[airminded88]

Did Flying Fortresses really fly at 40,000 feet over the desert?

 

[tomo pauk]

According to Peyton Magruder, the wing was changed in response to the USAAF desire to decrease wing loading. This was necessary due to the lower than design spec take off power of the early R-2800. But he then goes on to lament the massive increase in gross weight imposed on the design by the USAAF. The B-2 had marginally more powerful R-2800-41 engines, 1920 bhp for take off, compared to 1850 bhp for the -5s in the B-26, B-26A and the first 81 B-26Bs, but the B-26B-10 got no increase in power to offset the increase in gross weight.

A good "what if?" how much better would the B-26 have been with the same engines installed in the exalted A-26? We'll never know, because design improvements were halted in 1943. Even the canted wing of the F/G versions was snuck in and only retroactively approved.

British 'aircraft data card' gives 2000 HP for the R-2800-43 (onborad of Marauder III), for 305 mph at 15000 ft, so there is next to no improvement with engines from A-26 that were of same generation and power as the -43*. What A-26 have had was the next-gen wing, with slotted Fowler flaps - one enables both high speed, other the docile low-speed handling. Unfortunately, Mr. Marguder will not cover the question of why there were no Fowler flaps installed, if even of 1st generation, on the B-26.
The USAAC/USAAF was probably to blame for B-26 having how much - 7 to 9 crew members, a thing that pushed the size & weight of the fuselage; a mistake that was not repeated with A-26.
An even better what if would've been the 'thin fuselage' B-26 tailored for 4-5 crew max, hence much lighter, where the historical engines & wing will suffice, hopefully with ejector exhausts, if not of 2-stage or turbo varety, .

*that is for ww2 machines

 

[tomo pauk]

I have followed this thread with interest.

A question,

Below 15,000', why are you all considering the Allison engined P51 as inferior to the Merlin engined P51?

The only time fighter aircraft typically climbed above this altitude was to escort or intercept high altitude bombers... before 1944 this must not have happened much, at all.

Hello

The Allison engined P-51 still has much less power under 15000 ft than the Merlin Mustang, also the Mustang I/P-51 does not have drop tanks. It won't climb very when compared with light weight Euro/Japanese competition.
Before 1944 there was plenty of escort done, both by Axis and Allied air forces; eg. the Fw 190 drivers feared the escorting P-47s in second half of 1943, as we could read on the documents kindly provided by Steve/Stona.

...
My understanding is that below 15,000' the Allison engined Mustang was in fact faster than the Merlin engined Mustang. Additionally it could run at lower RPM than the Merlin which extended range, was lighter, and had better overall durability, especially in the desert as has already been brought up.

So I am curious as to why the P51A gets no love? Perhaps we need a "most underrated aircraft of WW2 thread".

I'm not sure that Allison Mustang was faster at any altitude than Merlin Mustang.
P-51A and P-51 are not the same aircraft. The P-51A/Mustang II was a later model (Euro/Asian use from Sept 1943 on) with better engine, drop tanks and only 4 .50s. With only 310 examples produced, it was hardly in position to carve it's name.

 

[Venturi]

Hi Tomo!

The Packard Merlin V-1650-3 at 60.5" of boost (sea level), regulated, made 1450hp

The Allison V-1710-39 at 56" of boost (sea level), regulated, made 1470hp

The Allison which was not regulated (by omission of manifold pressure regulator) theoretically could produce up to 65" of boost at sea level without ram and there are anecdotal stories of this occurring with the Mustang I in British use.

I agree the Merlin was a better performer overall due to it's more advanced supercharger.

But the basic Allison was a pretty good unit.

 

[tomo pauk]

The V-1650-3 operating on 60.5 in Hg is making military power (15 min duration), contrary to the V-1710-39 making war emergency power (5 min) on 56 in Hg. When on WER, the V-1650-3 will be doing 67 in Hg on 130 PN fuel, meaning the power of ~1600 HP.
At 10000 ft, the V-1710-39 will do ~1250 HP, vs. 1600+ for the V-1650-3.

...
I agree the Merlin was a better performer overall due to it's more advanced supercharger.

But the basic Allison was a pretty good unit.

Agreed all the way.

 

[Greg Boeser]

Tomo, I always wonder how the Marauder II is rated differently than the B-26C, which it essentially was. I suppose it has to do with the weight at which the aircraft was tested. Or was it good Martin Co. propaganda? The R-2800-43 was rated at 1920 bhp for takeoff. I'm not that well informed about the model installed in the A-26.
As far as design decisions, the route that Martin took was to build the aircraft around the bomb bay. They copied the bomb bay of the B-17, which determined the circumference of the fuselage. So in effect, they were shrinking a heavy bomber to fit the specifications of a fast medium, and in the process, retained much of the heavy bomber's baggage.
The A-26 was a bigger, more powerful A-20, and retained the compactness of the light bomber. The same could be said for the B-25, which was a bigger version of their failed NA-40.

 

[fubar57]

6 books on the B-26 and not one mentions "....the route that Martin took was to build the aircraft around the bomb bay. They copied the bomb bay of the B-17, which determined the circumference of the fuselage...." The USAAC wanted a medium bomber that could carry..."the same bomb load as on the Boeing B-17 Flying Fortress four engine heavy bomber and a top speed of 300mph..."

 

[drgondog]

The Allison 1710-81 in the P-51A will pull a P-51A at MP faster than the 1650-3 and -7 in the P-51B/D under 12000 feet. Both weight of airframe (induced drag), and excellent performance at low/medium altitudes for the 1710 contributed.

 

[Greg Boeser]

Fubar, vis the USAAC specification, you are correct. Wolf's Martin B-26 Marauder, the Ultimate Look: From Drawing Board to Widow Maker Vindicated, states that the bomb bay was designed based on the measurements copied from the bomb bay of the B-17. However, I confess that the book also states that the fuselage diameter was determined by the width of the cockpit. The USAAC requirement to carry thirty 100 lb bombs was the reason that the aft bomb bay was added to the design, since the B-17 bomb bay had only 20 stations.

 

[tomo pauk]

Tomo, I always wonder how the Marauder II is rated differently than the B-26C, which it essentially was. I suppose it has to do with the weight at which the aircraft was tested. Or was it good Martin Co. propaganda? The R-2800-43 was rated at 1920 bhp for takeoff. I'm not that well informed about the model installed in the A-26.
As far as design decisions, the route that Martin took was to build the aircraft around the bomb bay. They copied the bomb bay of the B-17, which determined the circumference of the fuselage. So in effect, they were shrinking a heavy bomber to fit the specifications of a fast medium, and in the process, retained much of the heavy bomber's baggage.

The Marauder III in RAF nomenclature was a cumulative name for several B-26F sub-variants. I agree pretty much re. bolded part; quirk is they (USAAC? Martin?) also retained such a hefty crew requirement that furthed drove the size & weight of fuselage up.
The A-26 is noted as B-26 in the attached table, eg. as per post-war nomenclature. The (X)R-2800-27 was the during-the-war engine used on the A-26B.

The A-26 was a bigger, more powerful A-20, and retained the compactness of the light bomber. The same could be said for the B-25, which was a bigger version of their failed NA-40.

The A-26 emerged from a clean sheet of paper, incorpotating then-current cutting edge in aerodynamics, plus with remotely operated powered turrets. With the wing span of 70 ft it was hardly within confines of light bomber category IMO.

 

[tomo pauk]

The Allison 1710-81 in the P-51A will pull a P-51A at MP faster than the 1650-3 and -7 in the P-51B/D under 12000 feet. Both weight of airframe (induced drag), and excellent performance at low/medium altitudes for the 1710 contributed.

A quick glance at Williams' site shows P-51B (-3 engine) doing 3500 fpm at 10000 ft, vs. P-51A doing 3250 fpm; granted the P-51A is faster at 10400 ft. However, the P-51D matches the P-51A at 10000 ft in speed, and it is further superior in climb.

The P-51A produced instead A-36 would've been a major boon to the Allies IMO.

 

[drgondog]

Tomo - the sole point I was making is that the P-51A with the 1710-81 (more powerful than -39) was faster in MP than the P-51B/D in MP under 12000 feet. The P-51B always out climbed it.

 

[Greg Boeser]

Tomo, when the Martin B-26 was designed, power turrets were in their infancy. The Martin turret, developed specifically for the B-26 was a very successful design, used in nearly all US bombers during the war. Remote turrets were not yet perfected, the Bendix turret most commonly used in the early war was notably inferior.
There were many proposals to modify the Martin B-26, with an eye toward reducing weight, however, few were ultimately accepted due to the impact on production rates. In 1943 a USAAF directive basically froze Marauder development in place. The B-26 soldiered on with its inherent limitations, while Douglas had the luxury of developing the Invader using technology that came of age after the Marauder was introduced.

 

[tomo pauk]

Greg, don't get me wrong - I'm not criticizing Martin for a non-installation of a power-opearted turret (whether remotely- or 'directly-' controled) in the early days of the B-26.

Had the costumer (USAAC) been more modest (realistic?) with some requirements, esp. re. crew size/accomodation, had Martin/Marguder installed better Flap system, had the best possible R-2800 got installed, had the, now USAAF managed to restrain themselves from again upping the capability (= weight) - then yes, we'd see the B-26 making 350 mph by 1943. But too many 'if they only did this is' are involved, and B-26 historically went to the ever increasing weight & drag spiral, with engine power increased just a bit, and result was the slow bomber for standards of 1943 and later.
BTW - looking here, the wings were not that thick on the early B-26 - 16.7% at root.

The A-26 was ordered as an attack aircraft, that probably kept the crew size low, and indeed it used newer aerodynamics and other technological advances to it's advantage. The only 'legacy', or low hech items in 1944 were the engines, single stage supercharged R-2800s, B series, in production from late 1941/early 1942.

 

[tomo pauk]

Tomo - the sole point I was making is that the P-51A with the 1710-81 (more powerful than -39) was faster in MP than the P-51B/D in MP under 12000 feet. The P-51B always out climbed it.

Bill, the V-1710-81 was making less power in 'militar power' setting than -39, 1125 HP vs. 1150 (under 12000 ft, no ram). Deficit of 25 HP was due to the increased gearing of the S/C; benefit was that power was bigger at high altitudes.
In military power, the P-51A does ~375 mph at 10000 ft (chart), vs. the P-51B with -3 engine doing 395 mph (chart). The P-51D doing 400 mph at 10000 ft, mil power (chart).

 

[Venturi]

I see 394mph at 10000' for the P-51B at 1485hp output, while I see 375mph at 10000' for the P-51A at 1125hp. These are both "military power" ratings, however,

the P-51A seems to be good for 415mph at 10000' and 1485hp.

 

[Greg Boeser]

Tomo, it would appear that the Army did recognize the error of their ways in the decision to terminate the B-26 and B-25 programs in favor of the A-26 when it was finally ready. But the A-26 wasn't ready until late '43, and didn't enter combat until '44.