An Allison V-1710 with a two-speed supercharger in 1942

[Steamed_Banana]

Oh, and for what is worth the P-51H, P-82 had no maneuverability restrictions due to cg issues. Ditto the P-51B/D if 40 gallons were burned from the fuse tank on climb to altitude. Presumably the same for Spitfire

I think this was the norm for many fighters of what we might call medium range or better, including Spitfire VIII

 

[Steamed_Banana]

Spitfire IIA with 40 gal tank.
View attachment 879720
Tested at Boscombe Down in Sept 1941 (?) .
Some were flown by Sqadron Nos 66, 118, and 154.
I don't know if any squadron was fully equipped or not.
This was the 2nd attempt at fitting the wing tank. It had been tried on a MK I.
Somewhere there was a report on the MK I. The Report on the MK IIA gives speeds and climbs.
The MK IIB had metal alerions and handling was a marked improvement over the MK I and the plane was considered satisfactory as a fighter.
Granted this tank has a fair amount of drag and cost a bit over 20mph in speed. It also cost about 700fpm in climb under 20,000ft.
How much was drag and how much was weight can be argued. Fitting the fuel tanks inside would get rid of the drag (except for a few mph) but the weight is still a problem.
Engaging the enemy over the French/Belgian coast is problematic. Near the end of the misson/sweep (longer than a normal Spitfire) there isn't going be much difference.
At the start or entry into enemy airspace the planes carrying the extra fuel are going to have much degraded climb.
Early MK Vs (eight gun) show a bit better climb using standard 2850rpm and 9lbs climb compared to the MK IIs with Merlin XII engines. Above 20,000ft the MK Vs show more advantage.
MK Vs seem to show rather different performance from each other.
A MK Vb with standard tanks was within 15lbs of the MK IIA with the fuel tank. Extend range Vb might have had similar performance to a standard IIa? Or IIb? Is that good enough in late 1941?

Yikes that is horrific!

 

[Shortround6]

Er, it was in 1941 that my home city received its worst bombing raids. Even when Germany was daft enough to attack the Soviet Union there was a very real perception that, at best, an invasion of Britain was merely delayed. Whilst the Barbarossa assault continued forward and reached the gates of Leningrad and Moscow that perception was still current. It was only in 1942 that the halt of the Germans and some reverses for them changed the perception. Until then the home islands were, not unreasonably in the light of the time, under a genuine threat. The priority pure interceptor rôle was thus current until well into 1942. The last raid on my home city was in May 1944. The last cruise missile raid on London was on the 29th of March 1945. Dealing with V1 raids was very much an interceptor rôle, within a whole defence system.

We saw this again in the 1950s and 1960s when the emphasis of British fighters was to get fighters up and away to meet Soviet bombers as fast as possible in all weathers. Hence the English Electric Lightning with the climb rate of an angel leaving work on a Friday and the fuel storage of a human bladder with prostate difficulties.

Without the benefits of 20/20 hindsight and historical records, the perceptions of the government officials are important and which government officials and what was the actual danger.
The Royal Navy might have scoffed at a German Invasion in 1941, especially after they lost the Bismark, rest of their fleet wasn't in very good shape either. Doesn't mean the RN didn't think a renewed/expanded bombing offensive wasn't a danger. The RN needed fuel from tankers and supplies and food and.............
British army had their own thoughts. They had to be prepared if both the Navy and the RAF failed. They were also responsible for the AA guns, searchlights, etc and were right up there with RAF for blame when German bombers did their thing.
RAF thought they were the first line of defense and part of the RAF thought the best defense was a strong offence of bombing German industry. This was at a time when the RAF was doing good if it found the right city. They didn't know how bad they were. See perception again.
Civilian minsters were getting a minimum of 3 different opinions plus complaints from the civilians.
Telling the civilians to just "suck it up while we bomb the Germans" was not going to go well. They had to at least plan for and implement some sort of defense, how well it worked is certainly up to question. British were flying around with bombers with searchlights in the nose and no guns as night fighters and other bombers towing explosive charges on 1000ft cables to try to snag enemy aircraft.
Sticking with normal short-range interceptors as a large part of the air defense would seem to be quite reasonable.

 

[Steamed_Banana]

The question is for how long. I understand all the difficulties in terms of policy, perception, and the challenges of retooling factories but I really struggle to believe that they needed to manufacture Hurricanes into 1944 or also Spit Vs into 1943. I think there was some overly conservative thinking going on.

More setbacks more quickly delivered to the Germans in North Africa in 1941-42 could have reduced the threat on the Home Islands as well. The British were looking for ways to keep up the attrition war with the Luftwaffe over the Channel, and mostly failing at that with the Rhubarbs etc., the costly Dieppe experiment and so on. But North Africa was right there, and turned out to be a real meat-grinder for the Germans by the end. Invading Italy and forcing the collapse of the Italian government didn't end the war but it certainly added to the problems for the Germans.

On the other hand, along the lines of how the British ground Army felt about a possible invasion of the home islands, it does not appear that they (forces of the ground army) were in any way ready to contend with their German opponents successfully in 1941 or probably in 1942. How much that could be influenced or changed by improved air operations is somewhat of a question, though clearly the DAF was a factor in the victory at Second El Alamein. So were US made tanks and artillery etc.

 

[Shortround6]

Yikes that is horrific!

very true, but that was considered 'state of the art" by some at the time.
At least it kept the fuel somewhere near the CG for and aft.
I doubt it was much safer in a bellylanding than an under-fuselage tank.

When they started stuffing fuel in the rear of the fuselage in they had the heavier two stage engine and the larger 4 blade propeller to balance out.
In fact some MK IXs were carrying five 17.5 lb ballast weights near the tail wheel. Adjust as needed for individual aircraft and equipment.
Merlin XX is heavier than a Merlin III or 45 but nowhere near as heavy as Merlin 61.
Not saying they could not put anything inside a MK V or MK V with Merlin XX but it is going to be closer to 30 gallons than 70 gallons.
30 gallons is better than nothing but 30 gallons does not turn a Spitfire into a Ruhr escort fighter either.

 

[tomo pauk]

Engaging the enemy over the French/Belgian coast is problematic. Near the end of the misson/sweep (longer than a normal Spitfire) there isn't going be much difference.
At the start or entry into enemy airspace the planes carrying the extra fuel are going to have much degraded climb.

Aren't we already at some height and speed during the entry at enemy airspace, while the enemy might not even started his climb to meet us?

 

[Shortround6]

On the other hand, along the lines of how the British ground Army felt about a possible invasion of the home islands, it does not appear that they (forces of the ground army) were in any way ready to contend with their German opponents successfully in 1941 or probably in 1942.

We are back to perceptions again. German army was all conquering in 1940-41, at least in perception. In reality? Forget Russia. Norway did not go well in 1940, German prowess or British mistakes? Germans lost a large part of their fleet. German airborne invasion? big fear in Britian in 1941, reality in 1940, a lot of problems and huge losses in transport aircraft and men.
Crete in 1941? again huge losses in men and transport. Ability to use airborne forces against England in 1941? Somebody in Britian should have been looking at photos of wrecked Ju 52s on the ground and counting them.
Germans cannot land 10 divisions in a few days on British soil. British navy may have known that. Army may not have. The Allies barely did it at Normandy in 1944. In fact, the Allies only managed to put 7 infantry divisions ashore in Sicily in 1943, with a lot more ships and landing craft than the Germans had.

How much that could be influenced or changed by improved air operations is somewhat of a question, though clearly the DAF was a factor in the victory at Second El Alamein. So were US made tanks and artillery etc.

Perception again. Some people in Britian, who should have known better, thought that the German army could get across the channel and start marching on London in short order and I mean march.
Few light tanks, even fewer mediums, few trucks, in 1940 they were planning (unknown to the British) to bring horses. In 1941 the British had almost a year to build AT guns, field guns, and lots of other stuff, like ammo. Germans had to bring everything with them. Get it ashore and try to move it several miles inland.
RN would have something to say about supply dumps on the beaches. The Germans did not have control of the sea or any way control the sea. disputing control is not controlling it.
Which leaders the British listened to could be important. British had to plan for an invasion, which limited overseas deployments, but the chances of the Germans succeeding were very small and using 20/20 hindsight almost non-existing. The only way the Germans could actually win is if the British totally screw up and lose.

 

[Engineman]

Aren't we already at some height and speed during the entry at enemy airspace, while the enemy might not even started his climb to meet us?

Yes, but climb capability is always a factor in combat, it is one of the performance variables that define possible advantage in a situation that requires manoeuvre to engage from a less advantageous initial position.
Worth noting that escort fighters may be tied to limiting escort parameters that mean they may almost definitely be at an initial disadvantage.

Eng

 

[Shortround6]

Aren't we already at some height and speed during the entry at enemy airspace, while the enemy might not even started his climb to meet us?

Maybe, Germans had radar in 1941, not as many as the British and maybe not as far ranged (?)
but that was a big problem of the British 1941 air offensive. Germans didn't come up to "play" unless they thought they had an advantage. They didn't really care if the British shot up a Belgian or French train or barge, they weren't German. They could "see" (radar ?) large formations of fighters at higher altitudes than the few low level radars.
They often picked or choose when to engage based on if they thought they could have an advantage.

And I keep saying, rate of climb of a fighter is an indicator of how well it can turn in fight. Rate of climb is an indicator of excess power and the fighter can use excess power to keep from descending when maneuvering or keep from descending as much. If one side decides to boom and zoom or just boom and fly away then a difference in climb speed doesn't mean much but if the two sides get into a maneuver fight the higher climb rate fighters will have an energy advantage.

 

[Howard Gibson]

This is a point that is constantly pushed and it's false, the Spitfire wasn't going to match the range of the P51 and it didn't have to, all it had to do was have operational flexibility by having the ability to carry more fuel, flexibility in increased range, increased cruising speed or loiter time and it could have had all that 12 months before the P51. As has been discussed instead of having factories making obsolete or rubbish aircraft or like MB make a 1943 aircraft in 1946 they could have been making or modifying Spitfires for specific roles, the Mk V could have had extra tanks and fit and finish adjustments afterwards so the production lines weren't effected, once the 60 series Merlins arrived MkIX's likewise could have had the same treatment which would have allowed escort missions to the Ruhr from late 1942, there was huge numbers of military complexes in the Ruhr that were well within the range of modified Spitfires that could have been pounded late '42 and right throughout 1943 which would have caused a major shift in Luftwaffe strategy which did happen in 1944 when they were pushed out of the low countries and forced back to Germany. We are not making a Mk 51 Spitang, what we are doing is best utilizing the extra power and performance offered by the newer engines as they are developed along with available factories to perform airframe improvements and then putting it all together to update tactics as the environment or mission required. Forget the rubbish constantly spewed about poor handling and the Spitfires inability to carry fuel, the fact is they did and all the fighters that came later all had the same COG issues, the same flight restrictions and required the same hands on control until the extra fuel as burnt off.

The Spitfires were perceived as interceptors. They needed maximum climb rate and maximum ability to catch bombers. Great Britain was not seriously bombed by manned aircraft after the Battle of Britain. The Spitfires had a job to do, and they did it. When the RAF flew daylight missions in Lancasters, they used Mustangs as escorts.

It is worth looking at 1943 to see how Supermarine and North American set about improving their aircraft. The P51D got a bubble canopy, an extra fuel tank in the rear fuselage, two extra machine guns, and hard points in the wings for drop tanks and bombs. The Spitfire_XIV got a bigger engine, which is the worst thing you can do if you want to extend the range. The climb rate and top speeds improved quite a bit.

Given the Spitfire_V's lack of performance against new Luftwaffe fighters, especially Fw190s, extended range was the last thing they needed.

 

[tomo pauk]

Yes, but climb capability is always a factor in combat, it is one of the performance variables that define possible advantage in a situation that requires manoeuvre to engage from a less advantageous initial position.

If there is a 'but', I discount anything before that. Even the 'yes'.

A long-range Spitfire of 1940 that cruises at 270-280 mph will be diving on the enemy that is still on the runaway or it is climbing, and can use the zoom climb to it's advantage. It is the enemy that needs to climb very fast.

 

[Engineman]

If there is a 'but', I discount anything before that. Even the 'yes'.

A long-range Spitfire of 1940 that cruises at 270-280 mph will be diving on the enemy that is still on the runaway or it is climbing, and can use the zoom climb to it's advantage. It is the enemy that needs to climb very fast.

That "but" is because your point was weak and bore little relevance to the general value of RoC capability in the WW2 escort fighter being discussed.
If you discount that the enemy has an early warning system to intercept raids that can pre-position it's intercepting fighter force at an advantageous altitude and position , then the
enemy would have to mount CAP and would position itself at an advantageous altitude by default. However, the Germans did have Freya radar in 1940 and interception of escorted raids could be done in a timely way.


Eng

 

[Engineman]

The Spitfires were perceived as interceptors. They needed maximum climb rate and maximum ability to catch bombers. Great Britain was not seriously bombed by manned aircraft after the Battle of Britain.

Although the "official" BoB finished in October 1940, the night Blitz continued until May 1941. Later heavy bombing continued with the Baedecker Blitz and operation Steinbock.

Eng

 

[tomo pauk]

That "but" is because your point was weak and bore little relevance to the general value of RoC capability in the WW2 escort fighter being discussed.
If you discount that the enemy has an early warning system to intercept raids that can pre-position it's intercepting fighter force at an advantageous altitude and position , then the
enemy would have to mount CAP and would position itself at an advantageous altitude by default. However, the Germans did have Freya radar in 1940 and interception of escorted raids could be done in a timely way.

My standpoint is that underscoring a single technical thing (= rate of climb) is a wrong approach.
Even the half-decent escort fighters can be concentrated on the area of interest, unlike the short-range defensive fighters. Having a 20-50% greater numbers, even before we account for the bombers the defenders need to cater for, is a greater deal than having 5% better RoC. Attackers can use zoom climb, the defenders might not be able to return the favor.
Escorts are already on some altitude, the defenders might not be; same for airspeed.
As for the radar coverage - the German radar coverage was next to non-existent in 1940 above France and Belgium.

For 1941 - RAF will need the Spitfire III with a normal drop tank.

 

[Engineman]

And I keep saying, rate of climb of a fighter is an indicator of how well it can turn in fight. Rate of climb is an indicator of excess power and the fighter can use excess power to keep from descending when maneuvering or keep from descending as much. If one side decides to boom and zoom or just boom and fly away then a difference in climb speed doesn't mean much but if the two sides get into a maneuver fight the higher climb rate fighters will have an energy advantage.

Having a better sustained RoC capability over your opponent is an advantage, especially if it is a large difference, say more than 10%. However, a 10% higher airspeed capability is a greater value in most circumstances, be it level speed or diving, as most circumstances will see the faster aircraft able to disengage and re-engage at will, whereas the slower aircraft with a better climb rate can only disengage by climbing if his faster opponent does not have excess airspeed for Zoom. Again, the bigger the difference in capability the more marked the strengths and weaknesses.

Eng

 

[MiTasol]

Extra fuel tanks do not need to be kept full, and empty fuel tanks don't add nearly as much weight.

The metal shell of tank weighs very little but the "bullet proof" covering was built up from multiple layers of rubber and/or other compounds and far from light. Below is a typical British covering - I do not have the specific pages for the Spitfire so I do not know if they used the CIMA or another covering. The total thickness was over 1/2 inch. The Dunlopillo then and Dunlopillo now are two very different things. Some coverings were built up using multiple layers of leather and rubber. All were heavy.
Plus the structure had to be reinforced to handle not only the loads from fuel static in a full tank but also the far greater loads imposed when doing combat with a half full tank where the fuel is sloshing from side to side. That additional structure must still be carried 24/7 when flying with empty tanks.

Add to that all the attaching hardware and the whole assembly becomes quite heavy. This is the rear tank on the Mk IX - my apologies for it being rotated but my graphics program is not being cooperative this morning - and that rear cross tube and all its attachment to the fuselage shell is not fitted on aircraft that do not have these tanks.

By the way, in all this talk about armor, it is worth noting that Spitfires up to I'm not sure which mark, or maybe all of them, had that big fuel tank in front of the cockpit which was not armored, or rather was 'armored' with aluminum alloy only which is more or less the same thing. Just one other little factor to consider.

And, starting very early in the war, the two tanks under that "armour" also had the same heavy "bullet proof" covering as discussed above.
There was also, admittedly light (4mm) armour in front of the top tank.

 

[Shortround6]

Extra fuel tanks do not need to be kept full, and empty fuel tanks don't add nearly as much weight.

True but depend on tank construction they were heavier than you might think.
From 1943 text book.
Integral tank..............1/4lb per gallon.
Conventional Aluminum tanks 3/4 lb for small tanks to 3/8lb per gallon for large tanks (over 100 us gallons)
Bullet sealing tanks can range from 0.7lbs per gallon to 1.5lbs per gallon.
The weight of the tanks is somewhat dependent on the shape, odd shaped tanks with high surface area to volume are going to be heavier.

You are often pointing out that P-40s were often used without their fuselage tank filled, which is true.

They were often tested this way, what they did operationally I don't know. It might have given the 'planners' a better Idea of what they could expect in combat, or it might have made the US planes look better in the brochures. I don't really care except to point out that this was US practice, not other countries and people should be aware of this when quoting test figures.
For some reason one test of a P-51A at 8000lbs with 105 US gallons on board. This may or may not be an error. To get that light they had to leave fuel out. But they sometimes counted the 105 gallons a service load and there was another 15 gallons counted as 'reserve'. A lot of unanswered questions in some these reports.

Sometimes for interception / point defense missions almost all fighter types were used with half fuel for better climb rate.

This calls for some very good judgment. You can't use much less fuel for starting, warm up and take-off without risk of engine damage. Climb to altitude is closer than some people think climbing slow uses less fuel per minute but takes more minutes. Getting an 8,000lb plane to 20,000 takes a certain amount of work, no short cuts. How many minutes for combat?
and the kicker. How many minutes do you want for reserve? Figuring out where you are after combat, getting back to the airstrip, and landing. Landing includes waiting your turn if a number of planes in the air or waiting for damage to be at least flagged, taxing into unseen bomb hole is not good, or waiting for other problem, like burning truck or tent near the runway to be taken care off. Or being told to use alternate field. Basically, taking off with half full tanks eliminates the cruise aspects of the flight and you don't get far (or long) on 1/2 tank. 1/4 tank can buy you a lot if you are not in combat. A-36 could use as little as 1/4 the fuel per minute as it did at high speed.
Not full tanks I believe, 1/2 tanks is a harder sell, at least for anything except special missions.

 

[Steamed_Banana]

Whether it was a good idea or not, they did it, starting in Java and Malaya as a desperate expedient for trying to deal with Japanese fighters - with Hurricanes, Buffaloes and P-40s. It was done at various times and in various places throughout the war.

 

[PAT303]

So what is the mission that no other fighter in RAF inventory could achieve better than a Spitfire with extra internal fuel?

Don't people read????, I clearly stated that having extra fuel allows for a whole range of different missions that historically the Spitfire didn't fly because it didn't have the range, if range wasn't important why did every fighter once suitable engines were available have aux tanks drop tanks or both fitted?.

 

[PAT303]

Ditto the P-51B/D if 40 gallons were burned from the fuse tank on climb to altitude.

I'm pretty sure I actually said that, more than once.