Allied AFs in 1943: realistic options for long range fighters?

[Vincenzo]

At 20000 ft, with wing racks (those cost 12 mph, but are a necessity for the long range) P-51A makes ~390 mph.

The 51 has low drag so is fast but at 20k has around 1100 HP... so around 10% less power of a Gustav and around 20% more weight...

sure is best had a 51A that nothing (or many others fighter)

 

[tomo pauk]

The heating tubes going in the area between the spars, starting from the radiator/intercooler (shaded tubes at at attached picture). I presume the installation of the wing tank dictated that?

Always assuming that the Germans oblige by sending the V1s in batches, which they often didn't.

I'm not assuming that Germans will oblige. If Germans send the V1s piecemeal, the easier task for defender.

Even those hidden in caves? Judging by the results at Watten, Wizernes, Siracourt, Marquise/Mimoyecques, and Rilly-la-Montagne, the bombers did a fairly good job, anyway, and not many of the ski-sites got away without a pounding (from the USAAF the RAF.)

From production lines, through transport channels/lines, up to the launching sites - with LW overstretched or blunted, and Allied AFs in even better shape than historically, the Allied bombers have free reign to make even a bigger dent on all parts of V1 production use chain.

And the Germans had a charming habit of firing the V2s from among the homes of Dutch civilians, so heavy bombers were banned (the only time mediums were used, it turned into a disaster,) and the hunting was done by the Spitfire XVIs with 1 x 500lb + 2 x 250lb bombs (usually,) but that was not possible until 1945.

No doubt Spitfires were capable machines, maybe even more than it was realized during wartime. Tanks for the tidbit.

 

[tomo pauk]

The 51 has low drag so is fast but at 20k has around 1100 HP... so around 10% less power of a Gustav and around 20% more weight...

sure is best had a 51A that nothing (or many others fighter)

You mean: better to have the P-51A, than nothing? I agree.
In the time the P-51A enters service, the LW introduces the G-6. It is hampered by two things here: worse streamlining than earlier Gustavs, and the Notleistung is still banned. So it can do some 395-400 MPH at 22000 ft. In other words, the edge over P-51A is rather thin. In case the G-6 gets gondola cannons (needed to kill the bombers), the situation worsens: 385 mph at 21000 ft.
Of course, the G-6 is not the only opposition in the MTO in second half of 1943. There are the earlier Gustavs, that should be faster when new, but they are not new now. The Fw-190A-5 is a worthy opponent, deployed in small numbers in MTO. The Italian serie 5 fighters are also there, speed comparable to 51A.
All in all, the Axis has tiny edge in speed, and better climb. The advantage in climb is irrelevant if the attacker arrives at good altitude. The numbers game is not something Axis was good at, so they look to be outnumbered soon. And then, the bombers are there, to make things worse - if the defenders go on escorts, the bombers can do their job, and return next day in ever increased numbers.

 

[Shortround6]

Tome, please forget the "yardstick" range when dealing with drop tanks.

While this is for the A-36 it may give some idea of the fuel burn for the Allison powered Mustangs.

http://www.wwiiaircraftperformance.org/mustang/A-36_Specific_Operating_Instructions.jpg

Allowing 5 min at Military power (12 gallons) 20 min at "normal" (max continuous) (36 gallons) and 20 minutes reserve at "minimum" consumption (12 gallons) you have a max of 120 gallons (US) for the trip home after dropping tanks and engaging in the fight. This is enough for 1.62 to 2.5 hours depending on cruise speed (75-60% power setting) used over enemy territory. Cruising home over open water and/or well away from enemy territory can use lower power settings. WER use and/or more reserve will affect this as will initial start up, taxi, take-off and early climb out (generally not done of drop tanks), some planes could not transfer fuel from drop tanks to airframe tanks, some could. I have no idea on the Mustangs except that no mention is made of it in the P-51D Manual.

Early Mustangs had a reserve setting in the fuel tank ( much like a motorcycle gas tank) that held a number of gallons in reserve.

 

[tomo pauk]

The P-51B/C/D with 184 + 150 (int + ext, 334 gals total) have had combat range (indeed, the radius) of 450 miles at 25000 ft, and 500 miles at 10000 ft, TO weight 10200 lbs. Pg. 550 at AHT.
That means all allowances are included - take off, climb to the altitude, combat (5 min on WER, 15 min on military) and 30 min reserves.
The P-51A, with 180+150 gals weighted 9600 lbs at take off, so the radius should be 500 miles.

 

[Shortround6]

The advantage in climb is irrelevant if the attacker arrives at good altitude.

No, it is not. Climb ability is an indicator of excess power at climb speed. or power to weight ratio at climb speed. Once the fighters have engaged in any sort of maneuver (even a 180 degree turn) they have bled off some speed. The difference in climbing ability is also an indicator ( although not an absolute one) of the planes ability to accelerate back up to speed or regain height lost during a maneuver.

As an old example ( because I do not have data on any newer planes) a Spitfire I doing about 300mph at 12,000ft can manage about a 2.5 "G" turn that takes about 2800ft radius and just 20 seconds to complete a 180 degree change of direction without loosing either speed or altitude. Any quicker turn will cause a loss of either speed or altitude and this is not a particularly hard or sharp maneuver. Planes trying to fight at higher altitudes have even more trouble, thinner air means less lift for the wings and less engine power. A poor climbing plane that arrives at the fight with higher altitude than it's opponent is going to get about one firing pass before the fight descends to lower altitudes, unfortunately if the poor climbing airplane is tasked with defending/escorting bombers it means it cannot really engage/pursue attackers at it is too easily pulled out of position. Depending on engine fitted an Allison Mustang could take around 1 1/4 to 1 3/4 minutes to climb 3000ft in the high teen range at best climb speed.

 

[Shortround6]

The P-51B/C/D with 184 + 150 (int + ext, 334 gals total) have had combat range (indeed, the radius) of 450 miles at 25000 ft, and 500 miles at 10000 ft, TO weight 10200 lbs. Pg. 550 at AHT.
That means all allowances are included - take off, climb to the altitude, combat (5 min on WER, 15 min on military) and 30 min reserves.
The P-51A, with 180+150 gals weighted 9600 lbs at take off, so the radius should be 500 miles.

True but if you add or use bigger drop tanks the combat radius stays the same because you still have the same amount of fuel to get back home once you drop the tanks.

 

[tomo pauk]

No bigger drop tanks here - notice that the same 75 gal ones are used by all the P-51s in the post.

The P-51A, arriving at good altitude, can do what is almost an US custom thing to do: make diving passes, fire at opponent, then trade speed for altitude. Rinse repeat. If it's pulled out of position, that can mean two things: either it's in a combat vs. opponent (good - the opponent cannot go after bombers), or it's free to re-engage the opponent. Keeping the speed high mean it should be able to climb back in timely manner.

 

[Vincenzo]

For keeping the speed high (manouvering) you need power.

Back on my former reply, with i writed Gustav i thinked the early G-2/4. The italian opposition were main C. 202 the series 5 fighters were from very rare to uncommon...

 

[drgondog]

The P-51B/C/D with 184 + 150 (int + ext, 334 gals total) have had combat range (indeed, the radius) of 450 miles at 25000 ft, and 500 miles at 10000 ft, TO weight 10200 lbs. Pg. 550 at AHT.
That means all allowances are included - take off, climb to the altitude, combat (5 min on WER, 15 min on military) and 30 min reserves.
The P-51A, with 180+150 gals weighted 9600 lbs at take off, so the radius should be 500 miles.

Tomo - the P-51B-5, and all subsequent models prior to 110 gallon Drop tanks in late May, had 92+92+85 gallons internal plus 75+75 external (269+10), and all the -1s were retrofitted with the 85 gallon fuselage tank. That extended the combat radius at least to 700+ miles out and back with reserve for combat and loiter. The 355th flew the longest roundtrip mission until late in thewar on a dog leg escort to Posnan on May 13, 1944. !470 miles round trip as well as shooting down 12 east of Berlin (incl 6 Me 410s).

 

[drgondog]

WER use and/or more reserve will affect this as will initial start up, taxi, take-off and early climb out (generally not done of drop tanks), some planes could not transfer fuel from drop tanks to airframe tanks, some could. I have no idea on the Mustangs except that no mention is made of it in the P-51D Manual.

Early Mustangs had a reserve setting in the fuel tank ( much like a motorcycle gas tank) that held a number of gallons in reserve.

SR - for what it is worth, I have never heard of transferable fuel in the production P-51A through D/K. The fuel selector switch in front of the stick has 5 positions only with no provision to feed from one to another from either internal or external tanks. When one thinks this through why bother. Take off max fuel all tanks, take off uses right main, then switch to fuse tank as soon as aircraft is trimmed and in formation. Switch back and forth between right external and left external until dry or released for combat. Switch to one of the Mains if fuse tank has been reduced to 25 gallons.

For most of the fighter pilots I have discussed this with, the 20-30 gallons remaining in the fuse tank during climb out and heading toward RV was used as 'last reserve' after all else burned down.

 

[tomo pauk]

Yes, Bill, I know that fuselage tank gave the Merlin P-51 a wider 'footprint'. The 184 + 150 gal tankage for the B/C/C/K serves as the closest comparison with the P-51A, since the figures for the combat range (radius) of the P-51A are hard to come by.

For keeping the speed high (manouvering) you need power.

Indeed you do. The low drag also helps. The Mustang's driver should know he's plane's strengths weakneses. Weakness is the ammount of power available above certain altitude. He can avoid doghfights in horizontal plane. Strength is the ability to turn the altitude into speed and vice versa, ie. forcing the combat in the vertical plane.

Back on my former reply, with i writed Gustav i thinked the early G-2/4. The italian opposition were main C. 202 the series 5 fighters were from very rare to uncommon...

Historicaly, the 1st P-51As arrived in front line units in June/July 1943. Indeed the G-2/G-4 should hold the advantage, but OTOH the MC.202 is at a distinctive disadvantage.

 

[Edgar Brooks]

The heating tubes going in the area between the spars, starting from the radiator/intercooler (shaded tubes at at attached picture). I presume the installation of the wing tank dictated that?

No, they're running between the mainspar, and the ammunition boxes, which allowed some of the warmth to reach the boxes, by passing in front of them, and they also acted as an extra line of defence, for the ammunition, from gunfire in front. It was found that heat directed straight onto the Browning gun breeches could cause "cooking-off" of the .303" ammunition, so it was better to warm the whole gun compartment.

I'm not assuming that Germans will oblige. If Germans send the V1s piecemeal, the easier task for defender.

Not if they're having to mount standing patrols, just in case, which is what did happen. At the speed of the V1, pilots couldn't sit on the ground, waiting; they had to be available, at a minute's notice, to go for the bombs which got through the gun belt on the coast, then do their interception in the space of around 60 miles, before they were forced to break off, to avoid running into the London balloon belt.

From production lines, through transport channels/lines, up to the launching sites - with LW overstretched or blunted, and Allied AFs in even better shape than historically, the Allied bombers have free reign to make even a bigger dent on all parts of V1 production use chain.

You can't have large bombers wandering about the French countryside, just on the offchance of finding a target, and Harris had other uses for them, Try hitting a railway line, from the average height of a heavy bomber; as someone said, it's like trying to stick a dart in a pencil line, from 20 feet.
Train-busting was largely left to the Typhoons, plus the American fighters who'd been released from escort duty, and could shoot up any targets of opportunity, on the way home.

No doubt Spitfires were capable machines, maybe even more than it was realized during wartime. Tanks for the tidbit.

As far as is known, no V2 was ever hit by the Spitfires, but it's reckoned that a lot of launches were probably aborted, due to the Spitfires flying overhead; the Dutch were delighted to see (and hear) them.

 

[bobbysocks]

reply within..

You can't have large bombers wandering about the French countryside, just on the offchance of finding a target, and Harris had other uses for them, Try hitting a railway line, from the average height of a heavy bomber; as someone said, it's like trying to stick a dart in a pencil line, from 20 feet.

the bombers didnt wander around the countryside but my dad told me it wasnt uncommon to see the germans launch them off when they saw a large bomber formation coming towards them. he said it was like they were afraid the bombers were after them but they never went after the launch sites...




As far as is known, no V2 was ever hit by the Spitfires, but it's reckoned that a lot of launches were probably aborted, due to the Spitfires flying overhead; the Dutch were delighted to see (and hear) them.

did any spits "tip" them???

 

[Edgar Brooks]

You'd have a heck of a job tipping a V2.

 

[bobbysocks]

dyslexic moment....

 

[tomo pauk]

The escort ranges targets.
Unfortunately for the Allies, it was 1944 until the best options became available. The attack from Foggia by the heavies is out of question prior November 1943.

 

[tomo pauk]

Back to my pet project

The P-47 (prior mid 1944, with 305 gals of internal fuel) shows both benefits and limitations of a plane that carries the drop tanks. With additional DT of modest size (75 or 108 USG), the radius (combat range, whatever the term you like more) grows some 50-65%, from 230 to 340/375 miles. The table at AHT book gives lower figures, only 125 miles with 305 USG (225 with 370 USG, both for later P-47Ds). The same book gives also the 340/375 miles for 75/108 belly tank.
Now with 216 USG of external fuel, the radius is further extended. The chart from above post gives 475 miles, that figure being in contrast with AHT table that gives 425 miles on 305 USG internal and 2 x 150 gals. The internal fuel being the limit now: the 370 USG internal and 300 USG external provide the radius of 600 miles.

Be it as it is, the 1st and easiest option for the P-47 is to go with 108 gal belly tank, for those 375 miles radius. Another option can be going for the 370 gals of internal fuel (the main tank grew in height to accommodate additional 65 gals), and/or going with wing tanks. Preferably using the A-36/P-51 racks, those are far less draggier. The 1st P-47s were self-deployed from the USA to the UK, in Aug 1943*, with 2 x 165 tanks, presumably without any ammo. So the 2 x 108 should not present too much for Jug's wings; the option that includes a removal of one HMG it's ammo could make the job easier on the wings.

 

[Shortround6]

Part of the reason for the big increase in radius can be found here;

http://www.zenoswarbirdvideos.com/Images/P-47/47TOCL.gif

even at 12500lbs it can take a P-47 between 78-90 gallons to warm out, taxi, take off and climb just 20,000ft. another 5,000ft cost another 13-15 gallons.

once at 25,000ft it can cruise at about 300mph for 95 gallons an hour.

http://www.zenoswarbirdvideos.com/Images/P-47/47FOIC.gif

Fuel burn can be 4.6 allons a minute at Military power and 3.5 gallons a minute at max continuous.

http://www.zenoswarbirdvideos.com/Images/P-47/47SEFC.gif

 

[tomo pauk]

Thanks - the table in the ATH indeed takes into account the warm up and take off (as an equivalent of 5 min at normal rated power), plus the climb up to 25000 ft. But...

The 5 min at WEP is not available for the most of the 1943 for the P-47. The military power is also reduced in duration to 5 min (vs. 15 min as in 1944). So the 1943 P-47 will use considerably less power for 5 + 15 min (military + max continous) than the 1944 P-47 (5 + 15 min, WER + military).
4.6 USG/min x 5 min + 3.5 USG/min x 15 min = 23 + 52,5 = 75,5 USG for 20 min of combat, 1943, vs:
5.25 USG/min x 5 min + 4.6 USG/min x 15 min= 26,5 + 69 = 95,5 USG for 20 min combat, 1944

So, in 1943 (prior the engine ratings were 'upped', anyway), the P-47 has a bonus of 20 gals = 60 miles, after the combat. That seem like the main reason for the mismatch between the map and table. One wonders, however, whether the radius for February of 1944 are for the non-WEP engines?