P-51 fuselage fuel tank

[drgondog]

They had the capability but they weren't using them

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The USAAF was slow to get drop tanks into production. They had the capability to use drop tanks but they weren't building them in anywhere near sufficient numbers until late 1943.

Notably, Lockheed and Curtiss and North American proceeded to develop and design wing and fuselage drop tank/sway brace capability in 1941/early 1942 on their own nickel. Spaatz was Chief Materiel Cmd for only a brief period, then Echols assumed command when Spaatz went to Air Plans - then in 1943 assumed command of 8th AF and brought Eaker as CO VIII Bomber Cmd.

 

[Reluctant Poster]

P47's were fitted with unpressurised ferry tanks when Spitfires were coming off the production lines with a 85G main tank. Sydney Cotton fitted a 20G seat tank in his PR ''Cotton Specials'', that tank alone would have totally changed the dynamic of how the BoB could have been fought.

Explain

 

[Reluctant Poster]

They had the capability but they weren't using them

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The USAAF was slow to get drop tanks into production. They had the capability to use drop tanks but they weren't building them in anywhere near sufficient numbers until late 1943.

To give an idea of how little importance the USAAF was attaching to long range they had actually STOPPED production of the 75 gallon drop tank.

The reality is that in the middle of 1943 the USAAF is not placing a high priority on escorts for the B-17 over Germany. They have transferred their longest range fighter from the UK to North Africa and they attitude towards drop tanks is lackadaisical to say the least. But the RAF is supposed to reduce production of the most important fighter in the ETO and MTO in order to compensate for the tardiness of of US. If the US isn't doing all it can why should the RAF.

Also note that the RAF was carrying all the load in defending the UK. One thing that Spitfire never gets credit for is the air tight cordon they placed over the UK. Between the Spitfire by day and the Mosquito by night the US never had to worry about their home base being bombed. When they did leave the protective cocoon of RAF Fighter Command they found out at great cost that the Russians did not have anywhere near that capability

 

[Reluctant Poster]

Thats the difference between the Americans and British, the British found excuses as to why they couldn't do it, the Yanks just got on with it.

It took the Yanks over a year a half from the first B-17 mission over Europe to get it on with it and build a viable escort force . In January 1944 they were still futzing around with adding drop tank capabilities to P-47 and P-51s. The P-38s were finally being delivered with leading edge tanks and the P51s with fuselage tanks. Retro fits kits for both those aircraft were also arriving . Its not an accident that Big Week didn't start until February.

Appendices M through P contain quite a bit of information on drop tank tests

 

[PAT303]

It took the yanks over a year a half from the first B-17 mission over Europe to get it on with it and build a viable escort force

But they did it that's the difference, the British new their fighters lacked range and that indirectly lead to the blooding of the RAF in 1941 over France. I don't buy we didn't have time, didn't have resources etc, they had time and resources to fit the Merlin 45, 20mm Hispano's, design belt feed, change over to constant speed props, fit pilot armor, metal covered control surfaces and finally the Merlin 60 series with all new cooling system and wings, fitting the 29G rear tank took no time in the MkV, stupid thing is after fitting them for ferry flights they removed them, Stupidity at it's worst.

 

[PAT303]

Explain

By having an extra 20G the fighters could have been launched earlier allowing for optimal positioning for attack. During the BoB fighters were held on the ground until the last minute, they had to wait until the plotters were satisfied what the target was before releasing the fighters for launch, this caused them to be constantly attacking from underneath or from less than ideal positions, that extra 20G would have had them at 20,000ft before attacking or likewise fuel to reposition.

 

[Reluctant Poster]

By having an extra 20G the fighters could have been launched earlier allowing for optimal positioning for attack. During the BoB fighters were held on the ground until the last minute, they had to wait until the plotters were satisfied what the target was before releasing the fighters for launch, this caused them to be constantly attacking from underneath or from less than ideal positions, that extra 20G would have had them at 20,000ft before attacking or likewise fuel to reposition.

The extra weight of the tank and fuel etc are going to weight as much as a second crew man which will have significant impact on the rate of climb.

 

[PAT303]

The extra weight of the tank and fuel etc are going to weight as much as a second crew man which will have significant impact on the rate of climb.

I was waiting for this exact reply. With an extra 10 minutes of fuel the need for max climb rate is null and void, as soon as the incoming raid's direction is plotted the fighters are launched and will be race tracking at 20,000ft before the bombers cross the coast, the need for a high climb rate is because they don't have enough fuel to do anything other than point defense. The P51 got rear Berlin tanks from late December '43? when the missions they flew required more internal fuel, and numerous different sized drop tanks.

 

[Sisu]

Just from a modern day perspective...a gallon of aviation fuel is roughly 6lbs...85*6 is 510lbs. In Betty Jane we were around 6,500-7000lbs, that's 4000lbs under gross weight, give or take. But, a tailheavy airplane is a tail heavy airplane. The addition of the rear instrument package, seat structure and a 220lb (average weight) passenger could be considered a rear tank half full of gas. The airplane was completely stable. We didn't pull more than 4.5-5gs but never had any indication of instability or "snatch". The controls in a Mustang are balanced but mildly heavy, even being aggressive you can't yank the stick around like a Pitts Special. The stall, even an accelerated stall gives you a ton of warning and recovers with even slight release of back pressure. The Mustang also has a powerful trim system...once in cruise flight you can set it and fly basically hands off, particulary in smooth air. The only time you have to re-trim the airplane is during power changes. I understand the wartime warnings and SOP regarding the fuse tank and aft CG...but it boils down to how you fly the airplane and knowing the complete envelope. The policy of burning off the fuse tank first served it's purpose. The Merlin burns a gallon a minute in cruise and varies at climb power settings...roughly an hours worth of fuel, which would get them to altitude and pretty close to any combat area, where they could switch to the drops.

jim

Thank you for this, Jim. I have always wondered if there were any handling issues due to the aft CG with all the TF-51D restorations we see these days. Doing the math gave me about half the weight of a full tank in WW2, so I assumed things are fine, but it's nice to have your post talking about the issue.

 

[GreenKnight121]

A P-38 with external drop tanks forced to maneuver was definitely an issue. McGuire discovered that issue too late.

McGuire knew that long before that day... it was in the squadron SOP (as it was in ALL P-38 squadrons' SOP manuals), and he was well-known for emphasizing to pilots his combat rules... one of which was to NEVER enter combat without first dropping the external tanks, another of which was to NEVER get into a turning fight at low altitude, and the third of which was to never enter a fight below 300 mph.

The fight that killed him was a mission where they were cruising at low altitude, and a single Japanese fighter "bounced" them from above - they began defensive maneuvers without gaining much speed. When the enemy fighter got on the tail of a US pilot McGuire tried to help - still with his tanks under his wing, at about 200', and well below 300mph, he then tried to turn into the enemy and stalled out.

He broke all three of the combat rules he himself actively taught - his fellow pilots were completely confused as to why he did that.

 

[gingerbob]

Didn't seem to bother the MkIX or MkXVI, every MkXVI had the 42-33G rear tanks from the factory.

No, they did not.

 

[drgondog]

McGuire knew that long before that day... it was in the squadron SOP (as it was in ALL P-38 squadrons' SOP manuals), and he was well-known for emphasizing to pilots his combat rules... one of which was to NEVER enter combat without first dropping the external tanks, another of which was to NEVER get into a turning fight at low altitude, and the third of which was to never enter a fight below 300 mph.

The fight that killed him was a mission where they were cruising at low altitude, and a single Japanese fighter "bounced" them from above - they began defensive maneuvers without gaining much speed. When the enemy fighter got on the tail of a US pilot McGuire tried to help - still with his tanks under his wing, at about 200', and well below 300mph, he then tried to turn into the enemy and stalled out.

He broke all three of the combat rules he himself actively taught - his fellow pilots were completely confused as to why he did that.

I suspect that self preservation was lower in his mind than saving his wingman. IIRC they needed all the fuel remaining in the tanks to get home safely, but frankly don't know where that information came from.