British escort fighter--what might it have been like?

[Shortround6]

My own opinion is they could have done better than they did.
They were not going to equal the Mustang.
1. The Mustang burned less fuel per mile at the same speed.
2. The Mustang held 150imp gallons without the rear tank.
3. If you could stuff 150imp gallons inside the Spitfire and try to fight with it would you overload the plane?

How much radius is needed to be considered and "long range escort"?
300 mile radius?
400 mile radius?
500 mile radius?
600 mile radius?

forget the drop tanks. How far can you get back from after dropping the external fuel. or count some some of the fuel from the drop tank on the Spit.

Packard V-1650-7 burned 77.5 US gallons (64.5Imp ?) for 5 minutes of WAP and 15 minutes of Military power. That should take care of any fuel in the rear tanks of a Spit and the 30 gal tank under the fuselage. ( I would let you hang a tank under each wing to even get to the battle).

So what do you have left? and we can assume that some of the fuel burned in take-off was replaced by return from the carb during climb out and cruise, a couple of gallons and hour?

 

[PAT303]

Here's my take, warm up taxi take off on main tank until to get to say 3000ft switch to rear upper 42G tank, that gets you at 20-25,000ft over France, once thats gone you switch to the 90G drop tank, the DT return feeds into the main tank filling it back up before overflowing back into the DT, you fly around the Ruhr looking for trouble running parallel to the channel to around 400 miles at the furthest point then drop the DT, that leaves you 96G main, 52G in wings and 33G in the rear lower, you switch to the leading edge tanks and turn for home looking for trouble along the way, if you get into combat you will still have at lest 70-80G left which is more than enough to get home with reserve. They made the Spitfire into the premier PR aircraft, then into the Seafire, stuck the Griffin in it's nose, designed folding wings for it, fitted bombs to it and even made it into a glider tug, I'm sure they could give it extra tanks and learn fuel management and tactics to get the best use out of it.

 

[PAT303]

400 mile radius?

To the Ruhr, shorter ranged MkV's escort out to 200 miles using DT's, P47's go out as far as they can before turning back, the escort Spits do the rest, forget Berlin, the B17's only bomb targets out to 400 miles until the P51's arrive in numbers. Use the assets you have to gain the best result, there was enough worthwhile targets within the escort Spits 400 Mile radius to keep everyone busy right into 1944.

 

[Shortround6]

Here's my take, warm up taxi take off on main tank until to get to say 3000ft switch to rear upper 42G tank, that gets you at 20-25,000ft over France, once thats gone you switch to the 90G drop tank, the DT return feeds into the main tank filling it back up before overflowing back into the DT, you fly around the Ruhr looking for trouble running parallel to the channel to around 400 miles at the furthest point then drop the DT, that leaves you 96G main, 52G in wings and 33G in the rear lower, you switch to the leading edge tanks and turn for home looking for trouble along the way, if you get into combat you will still have at lest 70-80G left which is more than enough to get home with reserve. They made the Spitfire into the premier PR aircraft, then into the Seafire, stuck the Griffin in it's nose, designed folding wings for it, fitted bombs to it and even made it into a glider tug, I'm sure they could give it extra tanks and learn fuel management and tactics to get the best use out of it.

I don't care were the fuel is located for take-off climb and form up and trip is located, Mount 3 tanks under wing if you need to.
The Problem comes in when the the tanks are dropped.

Were can you put the fuel and stay in CG limits and how much fuel can you hold and still meet your strength/weight limit/s.
P-51s were not flying at an 8 G limit, they were too heavy. Now how far down into the 7's do you go? A P-51 at 9132lbs is at a 7 G limit. A P-51 with full internal fuel was at about 6.27 limit. Tank weight for the rear tank on the P-51 seems to change? P-51B-c seem to need 255lbs for the tank and installation? while P-51Ds show a difference of only 55lbs ? misprint or you could take the tank out but leave piping, pump?. brackets, etc?

And it is not just about the fuel, how much did the extra tanks weigh and were they protected or not? Spitfire with rear tanks does have an electric pump on the bottom tank. Upper tank gravity feeds to bottom tank.
How much does the Spitfire weigh with all desired tanks fitted and with the amount of fuel for save combat flight aboard and how does that compare to the weight loading chart.

To get to 150 imp gallons and MK VIII needs about 195lbs of fuel plus the needed tank/s piping. This seems quite doable to me. The problem may be going much beyond it.
A MK VIII is already at 7800lbs. Clean. They were beefed up a bit over the MK IX but the MK IX was just under 7500lbs

 

[PAT303]

The MkV was loaded with 200G's of fuel for ferry flights so we know it can lift the weight, the MkIX lifted two 62G DT's plus had rear aux tanks in the USAF trails and they were cleared for RAF service with the rear 42-33G tanks plus a 50G DT as were all the MkXVI's. It doesn't matter if they are max loaded or outside G limits on take off and climb out because they are not going to fight until the rear 42G is gone and the DT jettisoned, both the Spit and 'stang were cleared for combat maneuvers with 33-35G in the rear tank and the DT dropped.

 

[PAT303]

How much does the Spitfire weigh with all desired tanks fitted and with the amount of fuel for save combat flight aboard and how does that compare to the weight loading chart.

Both the MkIX and MkXVI were factory fitted with all the tanks plus DT pipework.

Were can you put the fuel and stay in CG limits and how much fuel can you hold and still meet your strength/weight limit/s.

The MkXIV which is the MkIII on steroids was cleared for all combat maneuvers with the 90G combat tank fitted as well as having the leading edge tanks, we know the Spitfire can not only carry the weight but is also strong enough to do it.

 

[NevadaK]

Both the MkIX and MkXVI were factory fitted with all the tanks plus DT pipework.

The MkXIV which is the MkIII on steroids was cleared for all combat maneuvers with the 90G combat tank fitted as well as having the leading edge tanks, we know the Spitfire can not only carry the weight but is also strong enough to do it.

The section on drop tanks is informative.

Spitfire Mk XIV Tactical Trials

 

[PAT303]

The section on drop tanks is informative.

Spitfire Mk XIV Tactical Trials

Its interesting that the MkXIV heavier nose effects its handling more than the MkVIII or IX so the adding of rear tanks would be of benefit rather than a negative, the best escort Spitfire would be based on the MkIII but with the MkIX's rear tanks.

 

[SplitRz]

I think it would be the Whitley. It seems to also have had the "Power Egg" configuration for the engine/radiator etc. The Wellington and the Beaufighter also seemed to have "Power Egg" Merlins I don't know what would be involved in upgrading from the Merlin X to the Merlin XX. I would also reduce the armament to 4 Mgs. This seems to have been adequate for the Gladiator against single engine aircraft. It might also help with the wing thickness mentioned by Shortround6. If the concept worked, I would then cut back the Hurricane and Spitfire, because the M20 could be used for Home Defence on it's days off from escort missions. The M20 had the potential to create a ""Virtuous Circle".
,

The Gladiators armament was really only BARELY adequate - and even then, only against lightly built and or armoured opponents. Those who got the most out of it, like Pat Pattle, frequently used their skill to target specific parts of an enemy aircraft. But normal pilots would rarely be given that opportunity or have the skill. Four 0.303s really isnt sufficient - especially given that it was quickly realised that even 8 x 0.303 was less than ideal.

... and why should the number of guns make any difference to wing thickness? The Spitfire toted 8 x 0.303 in pretty much the thinnest wing of the time...

What would the M.20 have been escorting from home bases, where, and why?

 

[Shortround6]

.. and why should the number of guns make any difference to wing thickness? The Spitfire toted 8 x 0.303 in pretty much the thinnest wing of the time...

Well, it was one reason that the eight guns in the Spitfire were spread out so much.
No ammo belt had to cross over or under another gun.
Spitfire wing was the lowest thickness expressed in percentage of cord.
Actual wing thickness in inches or cm may not wind up first on the list.
Because of the wing shape of the Spitfire it maintained about 80% of it's wing cord out quite a ways.

A few simple numbers. The Spitfire had a 100in root cord (actually centerline under the fuselage).
A 80in cord wing at 13% is about 10.4in thick
A 70in cord wing at 15% is about 10.5in thick
A 60in cord wing at 17% is about 10.2in thick

Actual airfoils affect how much space you have forward and aft of the thickest point.
Spitfire used a wing roughly 1/3 bigger than many of it's European (and soviet) rivals which means actual thickness (ability to put things inside) was pretty good. The 13% thickness meant it was not paying as much drag as a big wing with greater thickness.

 

[yulzari]

The Gladiators armament was really only BARELY adequate - and even then, only against lightly built and or armoured opponents. Those who got the most out of it, like Pat Pattle, frequently used their skill to target specific parts of an enemy aircraft. But normal pilots would rarely be given that opportunity or have the skill. Four 0.303s really isnt sufficient - especially given that it was quickly realised that even 8 x 0.303 was less than ideal.

... and why should the number of guns make any difference to wing thickness? The Spitfire toted 8 x 0.303 in pretty much the thinnest wing of the time...

What would the M.20 have been escorting from home bases, where, and why?

Minor point but the Sea Gladiators, at least, (and I understand some late RAF Gladiators) came with mounting points for another pair of Brownings under the upper wings in the same manner as the common under lower wing ones. I read somewhere that these were used in a couple of the Sea Gladiators in Malta to give a six gun armament. Possibly taking advantage of the use of Blenheim Mercuries and variable pitch propellor which did excellent things to the climb rate and allowed an earlier interception or intercepting bombers only detected closer to Malta.
I refer folk to Gladiators & Hurricanes

 

[pbehn]

Estimates of required fire power to bring down a bomber involve a time calculation, this depends on how much time you think you have. The presence of escort fighters change the calculation drastically. As I understand it British calculations were based on a two second burst of fire, with a supporting escort forcing head on attacks or boom and zoom attacks 2 seconds is a pipe dream. Later the LW in a similar situation with bigger bombers to bring down installed ever heavier armament to bring down bombers with just a few hits.

 

[Admiral Beez]

Of the fighters that existed, the Spitfire. Another 40 imp gal behind the pilot, drop tank facility.

Exactly. There's no magic as to how with the same basic engine and similar dimensions that the Mustang (see comparison below, thanks to ChatGpt) was a long range fighter while the Spitfire was not. It's gas capacity. Just modify the Spitfire design to increase internal fuel and add drop tanks, as you suggest. The empty weight of the Spitfire's structure will have to increase to Mustang levels in order to support the heavy fuel load, larger 02 tanks, etc. Viola.

The Supermarine Spitfire Mk.V has a wingspan of approximately 36 feet 10 inches (11.2 meters) and an empty weight of around 5,610 pounds (2,543 kilograms). In contrast, the North American P-51D Mustang has a wingspan of about 37 feet (11.3 meters) and an empty weight of roughly 7,635 pounds (3,464 kilograms). The P-51D is slightly larger and heavier than the Spitfire Mk.V.

Now, besides fuel capacity, can we make the long range Spitfire a good long range fighter? Is the armament and ammunition supply sufficient? What about pilot comfort (noise, heat, ergonomics), systems to reduce instrument and control attention/input, and how about radio communication and situation awareness? Did any single engined escort fighters have autopilot?

 

[GrauGeist]

Due to the size of the equipment needed for an autopilot system, fighters were not equipped with them, the P-47N being the only exception that I'm aware of.

It was a feature found mostly in bombers and transports.

 

[cherry blossom]

Due to the size of the equipment needed for an autopilot system, fighters were not equipped with them, the P-47N being the only exception that I'm aware of.

It was a feature found mostly in bombers and transports.

There was an instrument called the PKS 12 fitted to some Fw 190s and to the Bf 109G-10/R6. I don't know what it could and couldn't do.

 

[Admiral Beez]

There was an instrument called the PKS 12 fitted to some Fw 190s and to the Bf 109G-10/R6. I don't know what it could and couldn't do.

Here's what ChatGPT says:

What was the purpose of the PKS 12 system fitted to some Fw 190 fighters?

The PKS 12 system on Fw 190 fighters was a pneumatic slat system designed to improve low-speed handling and control, enhancing the aircraft's performance during takeoff and landing.

https://chat.openai.com/c/8fdab502-4fd4-4bc3-bd64-b326c2dd3fa9

 

[Admiral Beez]

Due to the size of the equipment needed for an autopilot system, fighters were not equipped with them….

Noted. I'm no pilot, but I believe there were features on the P-51 that help on long haul flights, such as an auto throttle/mixture/pitch system and I believe an auto rudder trim. Perhaps the Spitfire has these already, idk.

 

[cherry blossom]

Here's what ChatGPT says:

What was the purpose of the PKS 12 system fitted to some Fw 190 fighters?

The PKS 12 system on Fw 190 fighters was a pneumatic slat system designed to improve low-speed handling and control, enhancing the aircraft's performance during takeoff and landing.

https://chat.openai.com/c/8fdab502-4fd4-4bc3-bd64-b326c2dd3fa9

Eric Brown said "but it was not easy to fly on instruments; indeed, the all-weather variants were fitted with the Patin PKS 12 course-steering autopilot" but what did he know.

 

[SaparotRob]

Eric Brown said "but it was not easy to fly on instruments; indeed, the all-weather variants were fitted with the Patin PKS 12 course-steering autopilot" but what did he know.

What would a Brit know about the Mustang.

 

[GrauGeist]

There's a difference between a three-axis autopilot and Auto-assist.

The Ju87 Stuka had an "auto-assist" (often erroneously referred to as an auto-pilot) that pulled the Stuka out of a dive, gained altitude and levelled off while the pilot was passed out from the dive's G-forces.

The Fw190A (and other BMW801 radial equipped models) had a "kommandogerat" system that automatically adjusted the engine's fuel mixture and other functions, so falls under the Auto-assist category.

However, the P-47N, because of it's size, was able to have a three-axis autopilot onboard.