Best US escort fighter in ETO during 1943?

[Shortround6]

I thought most of the problem was political, you don't get long range escort fighters until you ask for them and many insisted that bombers didn't need them for far too long.

That is the modern, easy, blame the generals for being stupid answer.
The real problem was that is pretty much impossible to build a single engine fighter that could reach the middle of Germany (let alone Berlin) until late 1942 or early 1943.
even 1942 P-38s with twin engines would have problems.

 

[DarrenW]

Not knowing as much about the Spitfire as I would like, which models were in prominence during 1943 and would there be one version best suited for high altitude escort duty?

 

[DarrenW]

I added the Spitfire into the mix, just in case parsifal would like to possibly change his vote.

 

[pbehn]

Not knowing as much about the Spitfire as I would like, which models were in prominence during 1943 and would there be one version best suited for high altitude escort duty?

Here is a good article on the subject.
Escort Spitfire - a missed opportunity for longer reach? - Royal Aeronautical Society

 

[pbehn]

I thought most of the problem was political, you don't get long range escort fighters until you ask for them and many insisted that bombers didn't need them for far too long.

That is the modern, easy, blame the generals for being stupid answer.
The real problem was that is pretty much impossible to build a single engine fighter that could reach the middle of Germany (let alone Berlin) until late 1942 or early 1943.
even 1942 P-38s with twin engines would have problems.

Not really, although there was a bomber doctrine, just looking at the Battle of Britain in 1940 may have prompted someone some where to think it may be a good idea to have long range on internal fuel as a good idea.

 

[wuzak]

Not knowing as much about the Spitfire as I would like, which models were in prominence during 1943 and would there be one version best suited for high altitude escort duty?

The Mk IX was prominent in 1943.

The Mk VIII was, slightly, better, but was just getting into production and were being sent elsewhere.

MK XII production had come and gone, but was not suitable for high altitude work anyway.

The XIV was just starting production, and would come into squadron service towards the end of 1943/early 1944.

 

[Shortround6]

The Problem was going from "good idea" to "actually possible".

We have had a number of threads on this.

It took several advances to make the long range escort fighter possible, short range could have done earlier but if you limit your bombers to the range of your single engine fighters then you don't bomb much of Germany.

Now please note that the P-47 had roughly double the "book" range of a P-39 and about 22% further than a P-40E while flying 10% faster.
And yet the P-47 is derided as being short ranged. At ridiculously slow speeds (like 200-220mph) and low altitudes the P-37 could fly twice as far as as an early Spitfire or Hurricane. The P-47 was a 1940 design and yes, while the R-2800 was something of a gas hog ( but then any 2000hp engine is) it carried 305 gallons of fuel.
To escort bombers you need to be almost as good as the defending fighters, not just show up. carrying enough fuel to fly for several hours after combat was too much of a weight penalty until you had really low drag airframes that could carry large amounts of fuel inside (the P-39 was low drag but carried crap for fuel). The Allies also benefited from 100-130 fuel. Trying to build an escort fighter using 87 octane fuel is going to be very hard. You are going to need a bigger heavier engine which means you can't carry something else ( large numbers of guns/ammo?)
You also need an engine that is compact and has a very good power to weight ratio.
The P-51 combined all three.
The P-47 and P-38 might have worked but at a much higher cost in in airframes, engines, fuel and even lives.
Now please note that a Hawker Typhoon has a range of around 500 miles on internal fuel at around 300mph (but at 15,000ft, pass on that for now) by averaging (kind of) the most economical and the max lean mistrue speeds. It has 154 inp gallons and the ranges are after it uses 34 gallons taking off. Now if you take out even 15 minutes of combat you have to take off around 180 to 225 miles worth of range from the 120 gallon capacity.
and we have to add back in the reserve to find airfield after crossing the coast.
SO how much fuel do we have to jam into a Typhoon to make an escort fighter and what happens to the performance once we stick in an extra 300-600lbs of fuel and fuel tank?
Speed won't be bad but what happened to climb and turn?

The P-47 wouldn't have worked with straight 100 octane (not 100/130), the P-38 would have been in trouble (limited to 1150 hp or so not the 1335-1425 engines of 1943-44) and so on.
Advances in propeller design also helped the later fighters.
Now we can argue about exactly when the balance tipped over but tip over it did. The escort fighter was just not technically possible in 1938-39-40. And remember the P-47 was ordered off the drawing board. Over 1200 on order months before the first one flew.

 

[DarrenW]

Here is a good article on the subject.
Escort Spitfire - a missed opportunity for longer reach? - Royal Aeronautical Society

The Mk IX was prominent in 1943.

The Mk VIII was, slightly, better, but was just getting into production and were being sent elsewhere.

MK XII production had come and gone, but was not suitable for high altitude work anyway.

The XIV was just starting production, and would come into squadron service towards the end of 1943/early 1944.

Thanks fellas for the great information and link. I will delve into it after work...

 

[parsifal]

Claiming that it would take "a lot' or "a long time" to adapt the spitfire to long range escort duty is just not supported by facts.

In 1945 with the deployment of the BPF with its complement of Seafire III (the basic airframe on which this navalised version of the Spitfire had been developed from was available since at least 1942. It took time to adpt this basic airframe because of issues relating to LG strengthening and compound wing folding…..issues that took a long time to solve. Endurance was another issue frequently raised in relation to the spitfire, and yet it took the maintenance guys of 801 and 880 sqns (the Seafire squadrons of HMS INDEFATIGIBLE no more than a couple of hours to adapt the Seafire to carry the 89 gallon slipper tanks that they had acquired from the RAAF.

The end result was a great boost in the Seafire's operational endurance to 4.5 hours. Suddenly, it was capable of engaging in RAMROD (offensive air superiority) missions and long range escort missions. Hellcat effective combat radius was 240 miles, the Seafire compared reasonably well to this with those slipper tanks fitted, with an effective combat radius of 220 miles at . However, it could still not match the performance of - a Corsair carrying a 1000lb bomb which could still fly further.

Drag did increase by as much as 10%, but when all aircraft in the Wing had been modified to carry the 89-gallon tank, it meant they could carry out offensive sweeps or strike escort duties to a useful radius of 225 miles was [for] 'Ramrod' ops" - The Seafire, David Brown

225miles would not allow escort to even the ruhr, much less to berlin or Schweinfurt/Regensburg. But it just about cover air attacks to the Ruhr.

Why the RAF insited on sticking to their problematic 45 gallon slipper tanks, or worse, their leaky 90 gallon tanks, is beyond me. The US type 89 gallon tanks (imperial gallons folks) was the way forward and easy to do.

With no tanks….ie relying on internal fuel only, the Spitfire had an effective combat radius of just under 100 miles. With the RAAF 2 x 89 gallon slippers fitted, this range increased to 225 miles. I have read that it also possible to add a further 2 x 13gal slipper to the outer wings. Ive never seen that but ive read that it was possible, with no wing strengthening required. By my rough reckoning the seafire with the 89 gallon tanks is consuming 1.42 gallons per mile. Potentially the additional 26 gallons of fuel carried in the outer tanks, increases its range to 240 miles

Extending the range of the spitfire was not difficult, it was just not tried really.

Supermarine Seafire: Variants

 

[eagledad]

Voted for the P-38. Lower altitude equals warmer cockpit and no dive restrictions. The problems with the Allisons and cold temperatures was also reduced. Operating at lower altitudes removed most of the problems that limited the Lightning at higher altitudes. See "A History of THE VIII USAAF Fighter Command" by Lt Col aldo Heinrichs, page 158, to get 8th AF pilots thoughts on the P-38 and lower altitudes.

Eagledad

 

[tomo pauk]

I thought most of the problem was political, you don't get long range escort fighters until you ask for them and many insisted that bombers didn't need them for far too long.

That is the modern, easy, blame the generals for being stupid answer.
The real problem was that is pretty much impossible to build a single engine fighter that could reach the middle of Germany (let alone Berlin) until late 1942 or early 1943.
even 1942 P-38s with twin engines would have problems.

Nancy, France to Berlin - 664 km (~415 miles) It was certainly feasible in 1937 with Hurricane-sized A/C + Merlin III + VP prop + 150 imp gals + 100 gals in drop tanks.
Japanese probably must wait until 1941 with historical Zero. The Ki 61 also used legacy engine and airfoil, still managed excellent range.

...
Now we can argue about exactly when the balance tipped over but tip over it did. The escort fighter was just not technically possible in 1938-39-40. And remember the P-47 was ordered off the drawing board. Over 1200 on order months before the first one flew.

(sorry for butchering the post)
Again, Japanese were very much escorting their bombers before Germany attacked Poland.

 

[Shortround6]

We may be having some problems in defining a "long range escort" is it a 200 mile radius? 300mile radius or perhaps 475 miles (distance from Colchester to Nuremburg)? forget Berlin for the moment.
We also have to compare like to like, as in flying over occupied/enemy territory (land) vs flying over open ocean.
The like to like also covers similarly equipped planes. Please remember that while a liquid cooled plane could be brought down by a single rifle bullet through the radiator any plane could be made to fail to return to base from a long flight by a single bullet (flak fragment) through an unprotected fuel tank.

This is why the radius of the escort fighter is defined/limited to the distance it can fly on the fuel contained in protected tanks after it drops external tanks AND engages in combat for XX minutes AND exits the combat area at a high enough speed to make interception difficult.
Some countries (Japan) may differ.

consider the P-40 for a moment, early ones had unprotected fuel tanks and the fuel system weighed 171lbs (includes lines,valves/pumps) and held 180 gallons, by the time you get to the "C" the "system" weighed 420lbs (protection) and capacity had dropped to 135 gallons. They rigged the planes to take the 52 gallon drop tank and got the range back but the plane would always be saddled with the 250lbs of extra weight from the protected tanks.

We have been over this many times.

We also have to avoid the trap of "back fitting" that is to say plane XX (Say Spitfire) had a radius of 220 miles in 1943/44, therefore they could have made it go 220 miles in 1940, if they had wanted to. This ignores the changes in engines/fuel and propellers that occured during that time.

If the British had Merlin 55 engines with 16lbs of boost (and four bladed props) during the BoB things would have been a bit different there too

For a contemporary view of the problem (and I have no idea what this guy was smoking) see.
bristol blenheim | 1940 | 0079 | Flight Archive
for a multi-page article.

 

[Shortround6]

I would also note that endurance (especially at 180-200mph) is NOT range in the sense of escorting (or even flying) over enemy land masses that have AA guns.

 

[DarrenW]

Has anyone looked at the U.S. Navy radius formula before and figured out how the calculated range would be different if flying in an ETO environment?

You would have to climb an extra 10,000 feet before starting your cruise (in the Hellcat's case, take 9 minutes longer while burning an extra 26 gallons of fuel), and of course fly at faster cruise to the target and back than in the PTO, descending only after leaving enemy territory. But the reserves look higher (60 min as opposed to 20 min) so would it basically be a wash or is there more to it than that?

 

[Shortround6]

The US Army figured 30 minutes for reserve in their charts. We may have used 20 minutes in some of our threads to try an give the idea a bit of a chance or because at some point 20 minutes was used by either the army or the British. 20 minutes is not a lot of time if you navigation is a bit off and/or unexpected clouds/fog are covering your planned landing field.

170 kts (195mph) at 1500ft is suicidally slow over enemy held land masses. You are a volunteer target for every machine gun that can point upwards on your route, let alone setting yourself up for a bounce from all but the most rookie of pilots.

There is a reason the Army used flying back out of the combat area at 210IAS (315mph true) at 25,000ft as an estimate for radius.

30 minutes at most economical is only about 21 gallons for the F4U or F6f and that is only going to last 15-20 minutes at cruising speeds that use lean mixture.

Compared to a P-47 the F6F has less internal fuel, more drag and less efficient engine at higher altitudes (25,000ft). The turbo with it's "free" hp comes into play at the higher altitudes and high cruising speeds.
we can argue about exact numbers but that is the basic situation. The F6F is never going to come close to the P-47 in radius of action in european conditions and in fact, from land bases in the Pacific the P-47 would have been the better option. That extra 55 gallons inside and the lower drag would still count.

 

[DarrenW]

Compared to a P-47 the F6F has less internal fuel, more drag and less efficient engine at higher altitudes (25,000ft). The turbo with it's "free" hp comes into play at the higher altitudes and high cruising speeds.

It's obvious that the larger fuel capacity of the P-47 gave it a longer range than the F6F. But I don't see where the F6F had more drag, as they burned basically the same amount of fuel while flying at the same power settings and in the same configuration (with or without drop tanks). And in optimum cruise their specific engines were developing roughly the same horsepower so the Thunderbolt's extra 300 horses would only come into play when operating above the cruise. No question though that the P-47 was more optimized for high altitude escort and was the better choice for this role in ETO.

 

[Glider]

Taking them one at a time

P39 - what can I say apart from - next
P38 - Had performance altitude issues in the west and the Germans didn't consider them to be a real threat
P47 - Only real problem was its poor climb which isn't a huge issue for the escort role as you get plenty of time to gain the altitude. A serious issue if it was trying to defend as an interceptor
P51 - Altitude performance a major handicap
F6f-3 - I think it overall performance would have been lacking against lighter German fighters
F4U a1 - Similar to the F6
Spitfire - clearly lacking range would be a serious threat if it was the defending fighter

 

[tomo pauk]

Taking them one at a time

P39 - what can I say apart from - next
P38 - Had performance altitude issues in the west and the Germans didn't consider them to be a real threat
P47 - Only real problem was its poor climb which isn't a huge issue for the escort role as you get plenty of time to gain the altitude. A serious issue if it was trying to defend as an interceptor. Dive speed is advantage.
P51 - Altitude performance a major handicap
F6f-3 - I think it overall performance would have been lacking against lighter German fighters
F4U a1 - Similar to the F6
Spitfire - clearly lacking range would be a serious threat if it was the defending fighter

P-39 - agree
P-38 - performance at altitude was either better or equal when compared of the LW fighters in a specified time frame, problems are insufficient heating for hi alt, big size (= LW can spot it and get their act together without much of problems, thus gaining a 1st shot advantage), low rate of roll; this is the only real LR fighter of the listed, as-is. Dive speed disadvantage,
P-47 - at altitude the rate of climb was not that bad vs. what LW fielded, speed advantage vs. LW above 25000 ft; will need wing drop tanks for actually long radius (450 miles, with reserves and allowances, on prescribed 310 mph TAS cruise)
P-51 - agree, plus there was no drop tank facility before too late for 1943 in theater
F6F - agreed, plus not a long range bird
F4U-1 - performance parity vs. LW, range is still not very good as-is
Spitfire - Mk VIII is the only contender with somewhat of a long range, but still of the P-47 or F4U calibre; performance parity or more

 

[DarrenW]

in fact, from land bases in the Pacific the P-47 would have been the better option.

Those are fightin' words to any Naval aviator!

Seriously now, being carrier based the F4U and F6F could easily make up any deficit they may have had with range. And they were also able to strike just as deep into Japanese held territory as any Army fighter, be it the P-38, P-47, or P-51. That's what made them so valuable, especially before the long-range N model Thunderbolts and P-51D Mustangs showed up in theater.

 

[Shortround6]

Not from land.
It took a while to get enough carriers to to be able to put carrier aircraft wherever and whenever the Navy wanted.

Please remember, it is the amount of fuel in the protected fuel tanks that governs combat radius, not how much you can strap underneath.