109G Vs Spitfire IX in '42

[fastmongrel]

Hello Juha what escort radius did the Spit MkVIII have with the extra internal fuel and the biggest slipper drop tank it could carry. I imagine it would still come up short compared to a Mustang but it would be interesting to see how far into Germany it could go with a decent amount of combat time available.

 

[drgondog]

Mr drondog
1)Statistis can be mislaeding 20% or 30% or 40% for 2-3 missions .So what? Thousands new bomberswere on the way.

The 'so what' is that every mission that went as deep as Regensberg and Schweinfurt suffered those losse and the 8th had still not commenced a campaign against Leipzig area refineries, much less attacks on Berlin.

Secondly, while the US resources were great, the position of Spaatz and his dedication to Daylight Strategic bombing was tenuous - he had just fired Eaker and replaced him w/Doolittle to command the 8th AF. Churchill nearly persuaded Roosevelt to abandon daylight bombing and join the RAF at night. The mere fact that the 8th AF even experimented with the notion of re-training B-17 and B-24 crews for the night time role was a serious note that the losses were un supportable politically

2)As far as i know night bombing was rejected by the americans as ineffective against military targets.(But it was very effective against civil population as discovered by the british)

It was rejected in 1942, it was rejected again in late 1943, but had the Mustang not made deep penetrations feasible with acceptable (average 2%) losses, daylight bombing would have continued only against targets which were covered adequately by existing escorts.

3)Bf 109G6 ,Fw190A5-6 , wasn t not enough to be equal or near equal to their foes. Because of the numerical inferiority should offer some edge in flight performance as in 1941/42.

They were lethal against Allied bombers of all types in the daylight. Even the NJG me 110, 210 and 410 as as Ju 88 were formidable absent Allied escorts. Left un molested, the USAAF could not prosecute deep strikes without risking losing their entire force.

As to numerical inferiority, they (LuftFlotte Reich) always had Local superiority until 8th AF switched Thunderbolts for Mustangs.



4)German factories produced more aircrafts in 1944 than ever before and the limiting factor was,as before , fuel.Which was not enough even before the bombing of the production centers. So Doolitle campaign only accelerated the events helped by tactical errors by the Jagdwaffe.

It was sufficient enough to fuel the LW over the beach head at Normandy had the LW had adequate pilots. The training deficiencies were compounded by the awful losses suffered by the Luftwaffe between January and June, 1944.

5)Aerial superiority over Normandy would secured by the Alleis even without P51 . On D day LW flew 100 missions over the Normandy. Without the spring battles over Germany lets say
that would fly 2000 missions. Alleis flew 14000. Is there any point to further disgus?

Absolutely - the huge advantage the Allies had was COMPLETE control of the air to the point that the Wermacht was denied mobilty during daylight. The losses to shipping and logistical capability would been very serious to the Allies had the LW been capable of such force on June 6. There is no question that the Allies would have prevailed at great loss to both sides but the invasion itself would have been in dire peril.

Mr Glider
I firmly consider P51 overated. P51H even more.I consider its claimed performance totaly unrealistic

You have a right to your opinion.

The real performance of the P-51H was far superior to the P-51D. Over rated is always possible but you have set the comparison criteria to claim either as 'overrated' or 'unrealistic"

 

[Juha]

Hello Fastmongrel
with 90 Imp gal drop tank and without rear fuselage tank max range for Mk VIII was 1265mls. The ferry slipper tank was 170 Imp gal, but that size was purely for ferry use. 90 gal was biggest for combat use for Spits, IMHO Mks VII and VIII could have utilised drop tanks up to 120-125 gal size in escort jobs but IIRC there were no that kind of drop tanks around. I don't have info on ranges with rear fuselage tank easily at hand. But IIRC Supermarine got the idea of rear fuselage tank from Mustangs. As escort radius my guess is that 1265mls max range means something like 450mls escort radius in ETO enviroment.

Juha

 

[davebender]

Why?

The P-51 was crucial to saving the U.S. heavy bomber force from destruction. That keeps the American heavy bomber barons in business but it has little to do with defeating Germany. The Red Army will seize Berlin during 1945 even if the P-51 had not been invented.

 

[davparlr]

COlin

It does however make the Tempest an option, if the P51 hadn't been around.

Hello
In a world without P-51B/C/D/K and before Tempest Mk V GB might have build more Spit Mk VIIIs and less Mk IXs and kept most of Mk VIIIs in ETO instead of sending them all to MTO or to Far East.. Spit Mk VIII had the range of 740mls with internal fuel vs that of Tempest Mk V's 760mls. And both had the option of 90 Imp gal in drop tank(s). That without late Mk VIII's rear fuselage tank. Spit Mk IX's range with internal fuel only was 420-434mls and 900-914mls with 90Impgal drop tank. Mustang Mk III had the range of 890 mls with internal fuel only and it could carry 125 Impgal in drop tanks with them its max range was 1445mls, so it still had clearly superior range but Spit Mk VIII had range for escort missions to Western Germany.

The critical data point for escort mission capability is internal fuel supply. Since drop tanks are typically jettisoned at first contact with the enemy, a successful escort must be able to engage in combat for an effective amount of time and be able to return to base. When comparing the internal fuel for the Tempest V and the Spitfire VIII to the P-51B/D, this is what you get. The information on the Tempest V and Spitfire VIII was retrieved from the internet. If there is better information or if I have used the wrong gallon, let me know.

Tempest V. The maximum internal fuel for the Tempest V that I could find is 162 gallons US.

Spitfire VIII. The maximum internal fuel for the Spitfire VIII is 144 gallons. I could fine no reference to a "rear" tank. If you have info on this, please let me know.

P-51B/D. The maximum internal fuel for the Mustang is 269 gallons. Some of this fuel must be burned off before combat for stability.

I have, on another thread, performed a rough analysis of American aircraft for the escort mission. Using some of that data, I calculated the following escort performance for a 400 mile mission, Western Germany.

Tempest V. Using the same fuel consumption as the P-51, about 66 gallons needed for 400 miles, the Tempest would have around 100 gallons of fuel for combat. At Normal Rated Thrust (NRT), this would be about 30 minutes fighting time. Decent.

Spitfire VIII. Using the same calculations the Spitfire would have about 64 gallons of fuel for combat, or about 30 minutes at NRT.

Mustang. I had previously calculated that the Mustang, on a 600 mile range mission, would have over an hour combat time at NRT. At 400 miles, combat time would be about an hour and a half, or three times the combat time of the other two fighters. I think this indicates the impact the P-51 had to long range escort and, just as importantly, long range interdiction. At 400 miles, it would take three Tempests or Spitfires to provide the same length Combat Air Patrol over a German airbase as one Mustang.

There is an interesting quote when the RAF compared the endurance and range of the Tempest to the Mustang III (P-51B)

Tempest V Performance Data

By comparison the Tempest without nose tank or long-range tanks, has no range. When the extra fuel is available it should have a little more than half that of the Mustang III fitted with two 62.5 gallon long-range tanks, but without the extra 71 gallon body tank.

 

[NZTyphoon]

Hello
Hello NZTyphoon
On Hurricane, without it FC might have for ex Gloster F5/34s which might well have been a better fighter but there would probably have been fewer of them. Spit and Hurri were not only options available to FC in late 30s

Juha

Hi Juha

Although the Hurricane and Spitfire were not the only options in the late 1930s - not forgetting that with all the problems involved with producing the Spitfire in 1938-39 the Air Ministry was keen on stopping production and replacing the Spitfire with the Westland Whirlwind - the reality is that these were the only front-line single-seat single engined fighters available in 1940.

Tempest V. The maximum internal fuel for the Tempest V that I could find is 162 gallons US.

Spitfire VIII. The maximum internal fuel for the Spitfire VIII is 144 gallons. I could fine no reference to a "rear" tank. If you have info on this, please let me know.

P-51B/D. The maximum internal fuel for the Mustang is 269 gallons. Some of this fuel must be burned off before combat for stability.

I have, on another thread, performed a rough analysis of American aircraft for the escort mission. Using some of that data, I calculated the following escort performance for a 400 mile mission, Western Germany.

Tempest V. Using the same fuel consumption as the P-51, about 66 gallons needed for 400 miles, the Tempest would have around 100 gallons of fuel for combat. At Normal Rated Thrust (NRT), this would be about 30 minutes fighting time. Decent.

Spitfire VIII. Using the same calculations the Spitfire would have about 64 gallons of fuel for combat, or about 30 minutes at NRT.



Mustang. I had previously calculated that the Mustang, on a 600 mile range mission, would have over an hour combat time at NRT. At 400 miles, combat time would be about an hour and a half, or three times the combat time of the other two fighters. I think this indicates the impact the P-51 had to long range escort and, just as importantly, long range interdiction. At 400 miles, it would take three Tempests or Spitfires to provide the same length Combat Air Patrol over a German airbase as one Mustang.

There is an interesting quote when the RAF compared the endurance and range of the Tempest to the Mustang III (P-51B)

Tempest V Performance Data

Are you working in US or Imperial gallons?

From the Pilot's Notes for Spitfire VII/VIII, AP 1565 P N, Air Ministry December 1943: Fuel tanks = Top Tank - 47 Imperial Gallons; Bottom Tank - 49 Gallons; two wing tanks (13 gall)- 26 gallons = 122 gallons internal fuel plus drop tank of 30, 90, 170 gallons. There was never a "rear tank" fitted to the VII or VIII.

2650 rpm Weak Mixture
+4lb/sq.in Boost: 71 gal/hr
+2 lb/sq.in Boost: 66 gal/hr
0 lb/sq.in Boost: 60 gal/hr
-2 lb/sq.in Boost:53 gal/hr

2,400 rpm Weak Mixture
+4lb/sq.in Boost: 66 gal/hr
+2 lb/sq.in Boost:61 gal/hr
0 lb/sq.in Boost: 55 gal/hr
-2 lb/sq.in Boost:49 gal/hr

2,200 rpm Weak Mixture
+4lb/sq.in Boost: 61 gal/hr
+2 lb/sq.in Boost:57 gal/hr
0 lb/sq.in Boost: 51 gal/hr
-2 lb/sq.in Boost:45 gal/hr

Air miles per Imp gallon = 4 at 260 mph at 15,000 ft at 2,650 rpm
AMPG = 7 at 170 mph (recommended I.A.S) at 15,000 ft at 1,800 rpm

Pilot's Notes for Tempest V AP 2458c, May 1944: Fuel = Main tank-76 gal; 2 inter-spar tanks (28 gal each)- 56 gal; wing tank port forward wing root (after first 100 Tempest Vs) - 30 gal= 162 Imp gal plus 2 45 gal drop tanks

recommended speed for maximum range = 210 mph I.A.S reducing to 190 mph I.A.S at 20,000 feet
Air MPG = 5.6 at 2,300 rpm

Pilot's Notes for Mustang III AP 2025G: Fuel = 2 wing tanks-76.5 gal = 153 imp gal [2 x 92 US gal=184 US gal]; fuselage tank (late models) - 71 imp gal [85 US] = 224 imp gal [269 US]

 

[davparlr]

Hi Juha

Are you working in US or Imperial gallons?

Good question. In references on the internet it is often hard to determine which measure is being used. Certainly for the P-51 it is US gallons. I also believe the Spitfire was in US gallons, which corresponds to your data, as I tried to verify with fuel weight from test sheets. Apparently, according to your info, I used imperial gallons and need to adjust my calculations.

From the Pilot's Notes for Spitfire VII/VIII, AP 1565 P N, Air Ministry December 1943: Fuel tanks = Top Tank - 47 Imperial Gallons; Bottom Tank - 49 Gallons; two wing tanks (13 gall)- 26 gallons = 122 gallons internal fuel plus drop tank of 30, 90, 170 gallons. There was never a "rear tank" fitted to the VII or VIII.

2650 rpm Weak Mixture
+4lb/sq.in Boost: 71 gal/hr
+2 lb/sq.in Boost: 66 gal/hr
0 lb/sq.in Boost: 60 gal/hr
-2 lb/sq.in Boost:53 gal/hr

2,400 rpm Weak Mixture
+4lb/sq.in Boost: 66 gal/hr
+2 lb/sq.in Boost:61 gal/hr
0 lb/sq.in Boost: 55 gal/hr
-2 lb/sq.in Boost:49 gal/hr

2,200 rpm Weak Mixture
+4lb/sq.in Boost: 61 gal/hr
+2 lb/sq.in Boost:57 gal/hr
0 lb/sq.in Boost: 51 gal/hr
-2 lb/sq.in Boost:45 gal/hr

Air miles per Imp gallon = 4 at 260 mph at 15,000 ft at 2,650 rpm
AMPG = 7 at 170 mph (recommended I.A.S) at 15,000 ft at 1,800 rpm

Pilot's Notes for Tempest V AP 2458c, May 1944: Fuel = Main tank-76 gal; 2 inter-spar tanks (28 gal each)- 56 gal; wing tank port forward wing root (after first 100 Tempest Vs) - 30 gal= 162 Imp gal plus 2 45 gal drop tanks

recommended speed for maximum range = 210 mph I.A.S reducing to 190 mph I.A.S at 20,000 feet
Air MPG = 5.6 at 2,300 rpm

Thanks for the great info, I have very poor British data. I'll look and see how close I came with my assumptions. Would you happen to have the data for normal rated power for the Tempest and Spitfire?

 

[Juha]

Hello Davparlr and NZTyphoon
NZT already answered D's question. Some points to add; Morgan's and Shacklady's massive Spitfire The History gives the volume of Mk VIII's wing tanks as 2 x 14 Imp gal and so the total internal as 124 Imp gal. It also claims that MT818, which was delivered on 13 June 44, was the first Mk VIII with 75 gal fuel tank behind the pilot. The plane was when the tank was full unstable but not viciously so. It was estimated that the a/c becomes stable after 37 gals have been used from rear tank. Its stability was improved when flying the rear tank full when the standard oil tank was fitted instead of PRU oil tank with bulged bottom cowling. It was considered that the a/c might possibly be accepted by Boscombe Down.. Morgan's and Shacklady's book being clip and paste type book the story absurdly ended to that. So it might well be that Mk VIIIs with the rear fuselage tank never went to service, and if they went they most probably had 74 Imp gals in rear tanks like late Mk IXs and XVIs. IIRC Quill writes something on Mk VIII and rear fuselage tanks in his Spitfire book but I don't have time to check what exactly.

One thing on Mustang III figures, according to USA 100.000 max range for P-51B/C with internal 269 US gal was 1275mls and for -51D 1250mls, so probably British Mustang III figures were without the rear fuselage tank or more unlikely British figures were much more conservative.

Hello NZT
Quote: "the Air Ministry was keen on stopping production and replacing the Spitfire with the Westland Whirlwind"

one important reason for that was that FC was committed to introduce 20mm Hispano cannon as its standard fighter armament and it was first thought that the cannon cannot be installed into the thin wing of Spit.

Juha

 

[davparlr]

Review and update of previous escort calculations.

Data for Spitfire and P-51 is a good approximation for assumptions.

Revised data. Tempest, when corrected for imperial gallons, has a combat time at normal rated power at 400 miles of 45 minutes or 50% of P-51 combat time.

Note: All three aircraft should carry 70+ US gallons in drop tanks to ensure full internal fuel at target area. Also note that early mission engagement of enemy forces would affect time on target.

 

[drgondog]

The Mustang III typically was not equipped with the 85 gallon fuselage tank - which greatly limited its participation in daylight escort roles to Eastern Germany, etc.

 

[NZTyphoon]

Good question. In references on the internet it is often hard to determine which measure is being used. Certainly for the P-51 it is US gallons. I also believe the Spitfire was in US gallons, which corresponds to your data, as I tried to verify with fuel weight from test sheets. Apparently, according to your info, I used imperial gallons and need to adjust my calculations.

Thanks for the great info, I have very poor British data. I'll look and see how close I came with my assumptions. Would you happen to have the data for normal rated power for the Tempest and Spitfire?

No problem: I've given the figures for the Spitfire VIII using normal rated power at various boost and rpm settings - anything over + 7lbs boost (when the Merlin started using a rich fuel mixture) was considered to be military rated power and the fuel consumption went up dramatically: maximum continuous cruise was at +7lb/sq.in Boost, 2,650 rpm fuel consumption 80 gal/hr

3,000 rpm Rich Mixture
+18lb/sq.in Boost: 150 gal/hr
+15 lb/sq.in Boost:130 gal/hr
+12lb/sq.in Boost: 105 gal/hr (2,850 rpm)

Same story for the Tempest: Normal rated power was obtained at settings below +7lb/sq.in Boost: Rich mixture cruise was at +4½ lb/sq.in Boost at 3,150 rpm: fuel consumption was 125 gal/hr in M ratio at 5,000 ft, 132 gal/hr in S ratio at 15,000 feet: weak mixture cruise was +3lb/sq.in Boost at 3,150 rpm: M ratio at 5,000 ft, 100 gal/hr.

M ratio at 5,000 ft
+3lb/sq.in Boost: 91 gal/hr at 2,900 rpm: 84 at 2,700 rpm
+1¾lb/sq.in Boost: 91gal/hr at 3,150 rpm:84 at 2,900 rpm: 78 at 2,700 rpm: 72 at 2,500 rpm: 66 at 2,300 rpm
0 lb/sq.in Boost: 58gal/hr at 2,300 rpm: -2 lb/sq.in Boost: 49gal/hr at 2,300 rpm: -4 lb/sq.in Boost: 42gal/hr at 2,300 rpm

Mustang III
maximum continuous cruise was at 46 inches Hg Boost at 2,700 rpm = 67 imp gal/hr or 81 US gal/hr at 2,000 ft (for every 2,000 ft up to 10,000 add 1.5 gal/hr) weak mixture: between 10 and 20,000 ft it was 40 inches Hg at 2,700rpm = 62 imp or 75 US gal/hr: between 25 and 30,000 ft at inches Hg Boost at 2,700 rpm = 63 imp or 76 US gal/hr

Pilot's notes for the Spitfire and Mustang (including Mustang III) can be found here

BTW the formula for converting British lb/sq.in (psi) ( inch lbf/in² is more accurate, but wasn't used) Boost to American inches of mercury (inches Hg or IN Hg also ") Boost: One pound-force per square inch equals 2.036 inches of mercury: the normal atmospheric pressure at sea level is 14.7 lb/sq.in, so a reading of +6 means that the air/fuel mix is being compressed by a supercharger blower to 20.7 psi . +25 means that the air/fuel mix is being compressed to 39.7psi so:

80.8 inches Hg=+25 lb/sq.in boost
66.5 inches Hg=+18 lb/sq.in boost
60.4 inches Hg= +15 lb/sq.in boost
46.2 inches Hg= +8lb/sq.in boost
44.18 inches Hg=+7lb/sq.in boost
42.1 inches Hg=+6lb/sq.in boost

the Americans usually worked in round figures so in the pilot's check list in the P-51B-1 Pilot's Flight operating Instructions for take-off the pilot used a maximum boost of 61 IN Hg at 3,000 rpm = +15 lb/sq.in - same in the Mustang III Pilot's Notes AP 2025G

 

[tomo pauk]

It is really cool to have all this wealth of data provided without going way to partisan re. this or that favourite plane. Thanks, people.

 

[claidemore]

Some late model Mk IX Spitfires had 154 or162 gallons of internal fuel. The two normal 48 and 37 gallon tanks, a 33 or 41 gallon rear tank, and two 18 gallon tanks in the wings.

 

[Shortround6]

See: http://www.spitfireperformance.com/spitfire9-fuelsystem-lr.jpg

 

[NZTyphoon]

Some late model Mk IX Spitfires had 154 or162 gallons of internal fuel. The two normal 48 and 37 gallon tanks, a 33 or 41 gallon rear tank, and two 18 gallon tanks in the wings.

Just thinking of the pilot having to manage a fuel system with several tanks. The Seafire 46 (and 47?) must take the prize for having the most complicated fuel system of any piston-engined single-seat fighter - when fully loaded there were the normal 36 and 48 gal upper and lower fuel tank:
four wing tanks of 2 x 12½ and 2x 5½ gal:
rear fuselage tank of 32 gal:
two 22½ gal combat tanks under the wings:
and a 50 gal drop tank under the fuselage:
TEN fuel tanks in total, 247 Imp gal.

The instructions in the Pilot's Notes (AP 2280 F G) include:
(b) Main fuel system including rear fuselage tank full.
Start and warm up and take-off on the lower fuel tank.
Change over to the rear fuselage tank at a safe height (of 2,000 feet) by turning ON the rear tank , switching the booster pump switch to REAR and then immediately turning OFF the lower fuselage tank.

When 2 to 3 gallons remain in the rear fuselage tank turn ON the lower fuselage tank, switch the booster pump to MAIN and then turn OFF the rear tank . Proceed as in (a) above.

Cf Corsair IV: Main Tank (inc. reserve of 42 gal) 197 Imp gal, Centreline drop tank 142 Imp gal = 339 Imp gal. There were also two underwing drop tanks totalling 274 gal = 613 gal plus optional wing tanks totalling 95 gal = 708 gal in six tanks.

The Seafire 46 highlights the main problem of adapting what was a short-range interceptor to a medium range carrier fighter. The minimum fuel consumption was 41 gal/hr at -2 lbs boost at 1,800 rpm, so the 5½ gallon wing tanks combined theoretically gave 16 minutes of endurance.
The Corsair's minimum consumption was 32 gal/hr at 22 In Hg and 1,800 rpm, with a 42 gal reserve - theoretically over an hour .