The P-38J and L in the European theater.

[Kevin J]

I'm guessing by that statement that P-51/-47 aircraft always had the drop-tanks released before they were "bounced"

I think they dropped them as soon as they entered what they thought would be the 'hot' zone. Except of course, Thunderbolts lumbered with belly tanks, they were 'screwed' because they couldn't drop them. You should remember that the Thunderbolt was developed in haste, about 18 months between first flight and service entry, 2 years between first flight and combat entry. The USAAF got it into service pretty fast as it had excellent high altitude capability which was needed in Europe, they sorted out the range issue later. The Mustang had already had the drop tank issue sorted before it went into combat in Europe in Dec 43. The P-51A of early 43 was drop tank compatible and the Na 73 had first flown a year before the Thunderbolt.

 

[Kevin J]

Yep, Us Americans had better eyesight and never got bounced.

When you're flying much higher and faster than the intercepting Germans then that should be the case. Its only when you're flying a Spitfire V, or even worse a LaGG-3 that you're really screwed.

 

[Shortround6]

The NA-73 first flew 7 months before the XP-47B. It also took quite a while to sort out the drop tank situation on both aircraft. Proper drop tanks being in very short supply in Europe in the fall of 1943.
The Initial P-51Bs arrived in England without either rear tanks or being drop tank capable (or drop tanks were not available) and their first few missions were without drop tanks. On their first missions with tanks they used 75 gallon ones, Lightings flying on the same missions are also using 75 gallon drop tanks. despite having used much larger tanks well before this. But there is a problem using some fuel tanks at high altitudes.
A few P-47s had been ferried to England using a pair of P-38 165 gallon tanks at the end of Aug 1943 but it is only in Jan 1944 that a program is started to re-equipe/refit ALL P-47s to take under wing fuel tanks or bombs.

Somewhere we may have the dates that various tanks went into service but it is a confused affair with some tanks being able to be used at low altitudes only and/or different pumps having to be fitted to the aircraft.

 

[Shortround6]

When you're flying much higher and faster than the intercepting Germans then that should be the case. Its only when you're flying a Spitfire V, or even worse a LaGG-3 that you're really screwed.

The US did not always have the altitude advantage. Between radar and the bomber stream flying at 180-200mph the Germans often had 1-2 hours warning of incoming raids. If the 109 couldn't get to 30,000ft in an hour the Germans should have just surrendered in 1943.

 

[Kevin J]

The US did not always have the altitude advantage. Between radar and the bomber stream flying at 180-200mph the Germans often had 1-2 hours warning of incoming raids. If the 109 couldn't get to 30,000ft in an hour the Germans should have just surrendered in 1943.

The Germans were sneaky, they just waited until the Thunderbolts ran out of fuel and turned home in 1943. Then they attacked the bombers,

 

[Navalwarrior]

The Germans were sneaky, they just waited until the Thunderbolts ran out of fuel and turned home in 1943. Then they attacked the bombers,

Resp:
Very true. So much so that the 78th FG (and 56th) fitted their old 200 gal Ferry Tanks (which hindered their maneuverability and often would not jettison) to their P-47s (July? 1943) in order to gain a few extra miles. The 78th actually caught the Luftwaffe off guard and shot down several of their aircraft. The Germans thought they were untouchable. Surprise, surprise!

 

[Navalwarrior]

The NA-73 first flew 7 months before the XP-47B. It also took quite a while to sort out the drop tank situation on both aircraft. Proper drop tanks being in very short supply in Europe in the fall of 1943.
The Initial P-51Bs arrived in England without either rear tanks or being drop tank capable (or drop tanks were not available) and their first few missions were without drop tanks. On their first missions with tanks they used 75 gallon ones, Lightings flying on the same missions are also using 75 gallon drop tanks. despite having used much larger tanks well before this. But there is a problem using some fuel tanks at high altitudes.
A few P-47s had been ferried to England using a pair of P-38 165 gallon tanks at the end of Aug 1943 but it is only in Jan 1944 that a program is started to re-equipe/refit ALL P-47s to take under wing fuel tanks or bombs.

Somewhere we may have the dates that various tanks went into service but it is a confused affair with some tanks being able to be used at low altitudes only and/or different pumps having to be fitted to the aircraft.

Yes to the 165 gal ferry tanks, but special plumbing was rigged to run fuel from these wing mounted tanks to the engine. The first wing pylon p-47s were for ordinance so we're not plumbed (crazy!). It would be months into 1944 before the plumbed wing pylons could carry drop tanks (P-47D-15s).

 

[Navalwarrior]

I think they dropped them as soon as they entered what they thought would be the 'hot' zone. Except of course, Thunderbolts lumbered with belly tanks, they were 'screwed' because they couldn't drop them. You should remember that the Thunderbolt was developed in haste, about 18 months between first flight and service entry, 2 years between first flight and combat entry. The USAAF got it into service pretty fast as it had excellent high altitude capability which was needed in Europe, they sorted out the range issue later. The Mustang had already had the drop tank issue sorted before it went into combat in Europe in Dec 43. The P-51A of early 43 was drop tank compatible and the Na 73 had first flown a year before the Thunderbolt.

Resp:
Actually, the A-36A was the first Mustang airframe to be drop tank capable. Since NAA incorporated wing pylons for ordnance, they went a step further and plumbed them (did not ask the USAAF). Since the P-51A soon joined the A-36A on the production line (built side-by-side) NAA only deleted the dive brakes (keep it simple, stupid!). The plumbing was retained.

 

[Kevin J]

Resp:
Actually, the A-36A was the first Mustang airframe to be drop tank capable. Since NAA incorporated wing pylons for ordnance, they went a step further and plumbed them (did not ask the USAAF). Since the P-51A soon joined the A-36A on the production line (built side-by-side) NAA only deleted the dive brakes (keep it simple, stupid!). The plumbing was retained.

Yes, just found that. The drop tank requirement wasn't required by the USAAF for the A-36A, and it was North American's decision to incorporate the feature. I guess it simplified production?

 

[pbehn]

Without enemy activity a P-51 B/D could fly from UK to Berlin return overland in UK and go back to Berlin then land in UK given perfect conditions. The radius lines drawn on a map are practical limits of how far they could escort a bomber group of the time in squadron strength allowing a time for them to actually fight. Operations always eat into any contingency so the contingencies built in were huge. Despite all the margins for form up escort combat and return pilots did land running on little more than fresh air, and an unknown number didn't make it back at all.

 

[pbehn]

No I read it somewhere on the internet. Yes, it could be dropped, but when you get bounced, do you have the time. The 45 gal had to be dropped. Anything above that and operating restrictions applied to the Spitfire flying it.

I believe it is a calculation, keeping a 45 gal slipper tank on throughout the mission increases the drag so much that its overall loss of range and top speed means it isn't a benefit.

 

[Kevin J]

I believe it is a calculation, keeping a 45 gal slipper tank on throughout the mission increases the drag so much that its overall loss of range and top speed means it isn't a benefit.

Loss of top speed with a slipper tank on the Spitfire Vb TROP was 5 mph with a 30 gal one rising to 16.5 mph with a 90 gal one.

 

[Greyman]

I believe it is a calculation, keeping a 45 gal slipper tank on throughout the mission increases the drag so much that its overall loss of range and top speed means it isn't a benefit.

At most economical speed, the Spitfire IX gained 287 miles in range if the 45-gallon tank was used and dropped halfway, and 251 miles if kept on throughout the mission.

 

[Mike Williams]

Let us not forget the Spitfire VII which had somewhat better range and was operational by early 1943.

Spitfire VII aircraft data card

The 90 gallon drop tank was in widespread use in UK based Spitfires. Note again the use of 90 gallon drop tank in the following combat report.

In this instance the mission was a sweep from Culmhead to Tours, a straight line distance of approximately 300 miles one way.

 

[Kevin J]

At most economical speed, the Spitfire IX gained 287 miles in range if the 45-gallon tank was used and dropped halfway, and 251 miles if kept on throughout the mission.

Flying at most economical speed anywhere near or over the coast of Europe in 1941/42 was going to get you killed. The Spitfire V's acceleration was slow, pilots were advised to fly at max cruise IIRC. As for retaining the 45 gal slipper tank, again its going to get you killed, even by Me 110's, as happened in 1941 to a squadron of Spitfires flying cover for a downed pilots rescue attempt off the Hague..

 

[Navalwarrior]

I believe it is a calculation, keeping a 45 gal slipper tank on throughout the mission increases the drag so much that its overall loss of range and top speed means it isn't a benefit.

Resp:
I would think the use of additional fuel (drop tank) puts the aircraft in an area it wouldn't have normally been. Looking at it from an economical or requiring a high rate of benefit would likely have prevented trials and testing from ever occurring. I know that in mid to late 1943 the USAAF 8th AF was willing to try anything (78th FG using 200 gal ferry tanks, etc) to get even a few more miles . . .to put them where they could engage the enemy.
Bomber loses were excessive, and cries from Bomber Command for more fighter coverage was heard. Just my two cents.

 

[pbehn]

Flying at most economical speed anywhere near or over the coast of Europe in 1941/42 was going to get you killed. The Spitfire V's acceleration was slow, pilots were advised to fly at max cruise IIRC. As for retaining the 45 gal slipper tank, again its going to get you killed, even by Me 110's, as happened in 1941 to a squadron of Spitfires flying cover for a downed pilots rescue attempt off the Hague..

45 gallons is about twenty minutes to one hours fuel from most to least economical. If you maintain a high cruise speed from start to finish, the extra weight and drag could mean that no real improvement in range resulted.

 

[Shortround6]

Flying at most economical speed anywhere near or over the coast of Europe in 1941/42 was going to get you killed. The Spitfire V's acceleration was slow, pilots were advised to fly at max cruise IIRC. As for retaining the 45 gal slipper tank, again its going to get you killed, even by Me 110's, as happened in 1941 to a squadron of Spitfires flying cover for a downed pilots rescue attempt off the Hague..

I believe they were instructed to fly at speeds that were a compromise between most economical and max cruise and to adjust the speed to the area they were in rather than a blanket one sentence "fits all" solution. Like flying under the German radar screens on the approach could be done at most economical, then increasing the cruise speeds.
A memo put out in Aug of 1942 has eight paragraphs and a further note/Memo called Safety Fast-Or Prune's guide for living is also about 8 paragraphs which repeats some of the same points. there was also an attached appendix of various speeds/altitudes and throttle settings for different fuel consumptions.
Several pf the paragraphs talk about mission planning and speeds to be flown in different areas that have different levels of threat.
For the fuel consumption at 10,000ft three different speeds are listed, each with 2 different throttle settings. There are a few misprints in the table.(or at least in the reproduction in one of Alfred Price's books). some of these throttle settings could show differences of 2-6 gallons per hour for the same speed (low rpm high boost gave best results, a fact well known before the summer of 1942.

Max cruise for a formation is also different than max cruise for a single airplane. In Aug 1942 the max cruise setting successfully used by a wing was 2650rpm and 5lbs of boost. Stringing your formation out with each plane running at a slightly different speed is also a recipe for disaster.

In the areas of the highest threat the highest possible cruise speed that the formation could use was the way to go. But blasting along at max cruise in areas of lower threat could well mean going for a swim or dinghy test.

 

[Mike Williams]

This page from 91 Squadron's Diary is interesting as it shows their first fighter sweep to France (Reams area, 11th May 1944 ) with Spitfire XIVs , use of 90 gallon drop tanks and miles covered (460). West Malling (their base) to Reims (their destination) is 213 miles in a straight line, one way.

 

[Kevin J]

This page from 91 Squadron's Diary is interesting as it shows their first fighter sweep to France (Reams area, 11th May 1944 ) with Spitfire XIVs , use of 90 gallon drop tanks and miles covered (460). West Malling (their base) to Reims (their destination) is 213 miles in a straight line, one way.

View attachment 512965

Spitfire XIV as opposed to Spitfire V which was the most numerous Fighter Command fighter until 1943. Less than 1000 Spitfire IX's were built between 1942 and 1943 and these had to be allocated between Britain, the Commonwealth, our European allies and the Americans being assigned to both the ETO and MTO. In my comments, I should have made it clearer that I was referring to the use of the slipper tanks by Spitfire V's, although I thought the restrictions on the larger tanks use continued.