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

[Shortround6]

A problem for the early Spitfire escort fighter.
Spit V...........6700lbs (?)
Spit IX.........7480lbs
Spit VIII......7800lbs

These are all clean, no drop tanks.

The Merlin 61 engine was about 250lbs heavier than the Merlin 45 which is ahead of the CG, Bigger radiator/intercooler is behind the CG but closer. Merlin 61s used 4 blade prop which is heavier. Some Spitfire IXs used about 87lbs of ballast. Some real early Spitfires used a lot ballast around the engine when they had the wooden prop so they is nothing really wrong with ballast.
The Early escort Spit does have problem with where and how big you can make fuel tanks with the nose being so light.
Given enough time that can be solved (extend the engine mounts and move the engine forward, make the fuselage tank/s bigger, etc) but we are starting to diverge from the simple modifications to Spitfire V needed for a 1941 escort fighter.

 

[don4331]

Adding Mk. XX Merlin is quick way to add 75 lbs. (+ move engine c.g. ahead a couple inches)
Leading edge tanks are also ahead of c.g. (although not by very much).
The 14 gal oil tank under Merlin is also ahead of c.g. (and available from Mk. I PR Spits.
Which would pretty much balance the 29 gallon fuselage tank

My questions is how much of an advantage over Luftwaffe fighters does a long range escort Spitfire have - with all those tanks full at start of combat, the Spit is over 600lbs heavier (~10%) than the ones engaging Bf.109s in BoB, and drop tank(s) attachments would be adding drag.

 

[PAT303]

British had about a year (and a bit more) get some the flaws out of the Spitfire and Hurricane before the war started.
Hurricane
2 blade wooden prop gone.
Fabric wings gone.
At least the need for protection was identified and work was being done.
Spitfire
2 blade wooden prop gone.
At least the need for protection was identified and work was being done.

IFF would start to show up in 1940.

Actual combat would show more changes.

The biggest one was speed, it appears that all the early fighters suffered from control stiffness once the 400mph barrier was exceeded.

 

[PAT303]

My questions is how much of an advantage over Luftwaffe fighters does a long range escort Spitfire have - with all those tanks full at start of combat, the Spit is over 600lbs heavier (~10%) than the ones engaging Bf.109s in BoB, and drop tank(s) attachments would be adding drag.

The MkIII outperformed everything in the sky until the FW190 arrived.

 

[Thumpalumpacus]

Both types were operated by the FAA, you threw criticism at the Seafire which never had naval operations as part of it's intended use when designed, the Corsair, on the other hand was prinsibly designed as a carrier aircraft yet it had every traite a naval aircraft shouldn't have. As pointed out the Seafire III was a very different aircraft to the earlier converted Spitfire MkV's so your statement that the Seafire wasn't worthy of mention doesn't stack up.

Thread is about British fighters, which the Corsair is not. Seafire II is not the Seafire. I find it funny I must point these things out, but there you go. Anyway, unless you've got something useful or enlightening, I'm done here. This sort of back-and-forth bores me. I prefer reading the info stuff, not the hobby-horse stuff.

 

[Shortround6]

The MkIII outperformed everything in the sky until the FW190 arrived.

Did it?
First Flight was March 16th 1940, engine was ????
nearly all sources say it was Merlin XX but that seems a bit early? Lumsden lists the Spitfire III under both the Merlin X and Merlin XX headings. Lumsden may be in error or perhaps a Merlin X was fitted for a short period of time while waiting for the Merlin XX?
In any case Spitfire III airframe was refitted with a standard wing (why?) and was delivered to RR at Hucknall for the Merlin RM6SM (not yet called the Merlin 61?) to be fitted in April of 1941. This took a while and the first flight with Merlin 61 (new name) was in Sept 1941. Which was just a few days (week or two?) after the 190 went operational.

Now we are debating if the Merlin XX powered Spit III was outperforming BF 109Fs available in the summer of 1941.

The Spitfire III when tested with the Merlin 61 was in poor condition but was unarmed (ports sealed over) but with ballast fitted. Normal radio but without IFF.
Performance with the Merlin XX was ????

 

[yulzari]

Just to vary from the Spitfire mode: assuming handwavium early mass production Griffon/Centaurus/Sabre/Vulture etc. then how about a Super Fulmar? Not the Firefly but the lighter Fulmar itself equipped with one of the above engines, although the Firefly would be an alternative I suppose.

Comes at the escort fighter from the ready to go with the range needed and a known quantity and swapping the 8x.303/4x.050 for 4x20mm cannon should be possible. Either one finds a use for the TAG in the back or use up his weight+kit for extra fuel. I do not suggest shrinking the design into an ersatz single seater but using the airframe as it was as much as possible. I do realise how long it took to get the Firefly into service and Fairey's other commitments IOTL.

 

[GrauGeist]

In reality, Britain did have a long range fighter candidate, but it was overlooked (or basically kicked to the corner):

The Boulton Paul P.94

The Defiant (and thus the P.94) was designed for ease of manufacturing, so the P.94 could have been manufactured in good numbers but it seems that at the time the P.94 was proposed, Britain hadn't foreseen the need for a long range bomber escort.

 

[Shortround6]

In reality, Britain did have a long range fighter candidate, but it was overlooked (or basically kicked to the corner):

The Boulton Paul P.94

With justification.

Is there any prove whatsoever that the P.94 ever went anywhere near the speed claimed for it?
Estimates don't count, they were estimating the Beaufighter would do 370mph
Which would have gone a long way to solving the escort fighter problem in 1940-41.
Reality is a Bitch.

 

[GrauGeist]

With justification.

Is there any prove whatsoever that the P.94 ever went anywhere near the speed claimed for it?
Estimates don't count, they were estimating the Beaufighter would do 370mph
Which would have gone a long way to solving the escort fighter problem in 1940-41.
Reality is a Bitch.

During the summer of 1940, the P.94 was flown as a demonstrator.

This was where it was learned that it was slower than a Spitfire, but faster than a Hurricane along with other results, like a good rate of climb, etc.

 

[tomo pauk]

Did it?
First Flight was March 16th 1940, engine was ????
nearly all sources say it was Merlin XX but that seems a bit early? Lumsden lists the Spitfire III under both the Merlin X and Merlin XX headings. Lumsden may be in error or perhaps a Merlin X was fitted for a short period of time while waiting for the Merlin XX?

It probably didn't overflew the 109F-4, that was available from June 1941. OTOH - air battles between late summer of 1940 and 1942 more than justified a 'super Spitfire', alas it was not meant to be.
Lumsden seems to be the only 'serious' author that lists Merlin X for the Spitfire III. Morgan & Shacklady note only the RM2SM (= Merlin XX) early on, and Merlin 61 later; obviously the later engine does not came into play before 1942.

In any case Spitfire III airframe was refitted with a standard wing (why?) and was delivered to RR at Hucknall for the Merlin RM6SM (not yet called the Merlin 61?) to be fitted in April of 1941.

Prototype of the Mk.III was the Mk.I N3297 that was taken from the production line at Woolston and was suitably modified (strengthening as required by a heavier powrplant, internal BP glass, less draggy U/C, more substantial cooling system); wing 'lost' the wingtips thus both wing span and area were a bit reduced in an attempt to improve rate of roll.
Clipped wings were not liked by the RAF brass since they were of opinion that the A/C will now more likely to be confused for an Bf 109. They asked that further Mk.IIIs are to be fitted with 'normal' Spitfire wing, that also made the wing loading more favorable.

Granted, a 'Spitfire III minus' was also an option IMO - the Merlin XII powered Mk.III airframe; alas, seems it was never in consideration.

Performance with the Merlin XX was ????

Morgan & Shacklady give 400 mph at 21000 ft. Table posted here is more optimistic.

 

[Deleted member 68059]

It probably didn't overflew the 109F-4, that was available from June 1941. OTOH - air battles between late summer of 1940 and 1942 more than justified a 'super Spitfire', alas it was not meant to be.
Lumsden seems to be the only 'serious' author that lists Merlin X for the Spitfire III. Morgan & Shacklady note only the RM2SM (= Merlin XX) early on, and Merlin 61 later; obviously the later engine does not came into play before 1942.


Prototype of the Mk.III was the Mk.I N3297 that was taken from the production line at Woolston and was suitably modified (strengthening as required by a heavier powrplant, internal BP glass, less draggy U/C, more substantial cooling system); wing 'lost' the wingtips thus both wing span and area were a bit reduced in an attempt to improve rate of roll.
Clipped wings were not liked by the RAF brass since they were of opinion that the A/C will now more likely to be confused for an Bf 109. They asked that further Mk.IIIs are to be fitted with 'normal' Spitfire wing, that also made the wing loading more favorable.

Granted, a 'Spitfire III minus' was also an option IMO - the Merlin XII powered Mk.III airframe; alas, seems it was never in consideration.



Morgan & Shacklady give 400 mph at 21000 ft. Table posted here is more optimistic.

The wing making it easily mistaken for a 109 was quite a minor complaint, the big complaint about the wing was that it made the landing run
a lot longer, which was considered bad enough to make it unsafe for use at night. (I have a letter from Dowding about it).

In any case nearly everything for the new Mk-III tooling and jig-wise regaring the new wing, was destroyed in a raid.

 

[SplitRz]

Adding Mk. XX Merlin is quick way to add 75 lbs. (+ move engine c.g. ahead a couple inches)
Leading edge tanks are also ahead of c.g. (although not by very much).
The 14 gal oil tank under Merlin is also ahead of c.g. (and available from Mk. I PR Spits.
Which would pretty much balance the 29 gallon fuselage tank

My questions is how much of an advantage over Luftwaffe fighters does a long range escort Spitfire have - with all those tanks full at start of combat, the Spit is over 600lbs heavier (~10%) than the ones engaging Bf.109s in BoB, and drop tank(s) attachments would be adding drag.

IIRC, P51s with full tanks were restricted in their manoeuvring and G limits too. I've read it elsewhere (from Winkle Brown I think) in addition to the following

"James Gibson former MP&P Engineer at Boeing, says on Quora. from Here's the real secret behind P-51B/C/D Mustang's range - The Aviation Geek Club

'The real secret to the Mustang's range was not the laminar flow control wing, or the Merlin engine. It was the addition of a fuselage tank behind the cockpit halfway through production of the P-51B. This additional internal tank increased fuel capacity by 85 gallons: original P-51Bs only had 184 gallons in the wings. The addition increased total fuel to 269 gallons or some 30%. Further adding two 75 gal drop tanks you reached 419 gallons. The later D&H models carried 110 gal drop tanks for 489 gallons. 'But when you carried so much fuel you had to be aware of which tanks you were using at which point in the flight. On take-off you used the rear fuselage tank. This tank effected the center of gravity of the plane. You didn't want to tangle with a 109 or a Focke Wulf when carrying fuel in the rear tank. So you burned it first and then switched to the drop tanks about halfway to Berlin.'

Gibson concludes;

'You would then burn off the drop tanks, hopefully before engaging enemy fighters. But if they struck early you could drop those tanks and thus be clean and maneuverable [though this might entail not completing the escort mission]. This was the fight profile that allowed the Mustangs maximum range and best performance when over target.'

So, to avoid any impression that I'm joining the boys towel-whipping each others buttock's with the union flag and stars and stripes on this thread, I'm not! Its merely worth noting that compromised manoeuvrability/handling/performance is going to be a price paid by any long range fighter until its burned off a lot of excess fuel weight / shed the drag of drop tanks.

 

[Thumpalumpacus]

Remind me to never, ever say anything negative about the Spitfire ever again. Sheesh.

 

[SplitRz]

Remind me to never, ever say anything negative about the Spitfire ever again. Sheesh.

Just tell Pat you LOVE the Spitfire and want to have its babies, and all is fixed!

 

[SplitRz]

Just to vary from the Spitfire mode: assuming handwavium early mass production Griffon/Centaurus/Sabre/Vulture etc. then how about a Super Fulmar? Not the Firefly but the lighter Fulmar itself equipped with one of the above engines, although the Firefly would be an alternative I suppose.

Comes at the escort fighter from the ready to go with the range needed and a known quantity and swapping the 8x.303/4x.050 for 4x20mm cannon should be possible. Either one finds a use for the TAG in the back or use up his weight+kit for extra fuel. I do not suggest shrinking the design into an ersatz single seater but using the airframe as it was as much as possible. I do realise how long it took to get the Firefly into service and Fairey's other commitments IOTL.

Its an interesting thought, given the Fulmar was already a long range fighter (Range: 780 mi on internal fuel) - but despite its pleasant handling, it was always going to be hampered by the critical aspect of poor speed and low rate of climb, I suspect. However many extra horsepower might have been crammed into it. Its a big aircraft with a thick wing designed to generate bags of lift for carrier ops. Any gains in hp aren't going to deliver much change to those built-in headwinds.

All that said, it did remarkably well in the MTO - especially when its had height advantage and radar direction and could make a diving pass. But we are back to the crux question - what is it going to be escorting and to where?

 

[Shortround6]

Its an interesting thought, given the Fulmar was already a long range fighter (Range: 780 mi on internal fuel) - but despite its pleasant handling, it was always going to be hampered by the critical aspect of poor speed and low rate of climb, I suspect. However many extra horsepower might have been crammed into it. Its a big aircraft with a thick wing designed to generate bags of lift for carrier ops. Any gains in hp aren't going to deliver much change to those built-in headwinds.

All that said, it did remarkably well in the MTO - especially when its had height advantage and radar direction and could make a diving pass. But we are back to the crux question - what is it going to be escorting and to where?

Fulmar gets a bit of a bad rap due to the altitudes it operated at.
Give it a Merlin XX it might have hit over 300mph at close to 20,000ft? It was around 20-30mph slower than a Hurricane at the same altitude (around 7-8,000ft)

It really won't do the job but it does point out what is needed.
You could probably have crammed enough fuel into a Spitfire to extend the range by 150-200 miles without going too crazy. After that things start to get weird.

 

[tomo pauk]

You could probably have crammed enough fuel into a Spitfire to extend the range by 150-200 miles without going too crazy. After that things start to get weird.

Shouldn't we after that (an before that) start attaching the drop tank(s)?

 

[SplitRz]

Fulmar gets a bit of a bad rap due to the altitudes it operated at.
Give it a Merlin XX it might have hit over 300mph at close to 20,000ft? It was around 20-30mph slower than a Hurricane at the same altitude (around 7-8,000ft)

It really won't do the job but it does point out what is needed.
You could probably have crammed enough fuel into a Spitfire to extend the range by 150-200 miles without going too crazy. After that things start to get weird.

The Mk ii had the Merlin XXX and it was pushing out 1300hp according to Fairey Fulmar (1940) and wiki - though I'm not enough of a Merlin engine expert to know how that compares to the XX and what rated altitudes either model was designed to run at? (It may even be an error, as although I've had a quick google, I can't find any reference to an 'XXX' model, which might suggest the Fulmar ii actually had the XX?)

As for altitudes? I don't think it does get such a bad rap on that basis tbh. It was specifically designed to operate at low to medium altitudes as part of its role and specification. It was never really intended to be an interceptor - it was principally and observer aircraft with fighter capability. It was not envisaged to be operating within the range of land-based aircraft and was intended to be a bomber destroyer. Aircraft operating over the med were usually going to be operating fairly low level and the Fulmar ii was pushing out its theoretical best of 272mph at around 7000ft which put it at less disadvantage than anywhere else at least!

A de-navalised (the FAA always added huge amounts of equipment and weight to their early war aircraft!), lightened single seat Fulmar derivative with a thinner wing and higher rated engine might have indeed been a possible contender for this 'what if' I guess.

However, given that the Blenheim was the only regular day light flying RAF bomber by the end of 1940 and into 41 - and carried a mere 1000lbs of bomb-load, I'm still pondering what raids this long-range escort fighter would be protecting in the early years of the war...

 

[tomo pauk]

The Mk ii had the Merlin XXX and it was pushing out 1300hp according to Fairey Fulmar (1940) and wiki - though I'm not enough of a Merlin engine expert to know how that compares to the XX and what rated altitudes either model was designed to run at? (It may even be an error, as although I've had a quick google, I can't find any reference to an 'XXX' model, which might suggest the Fulmar ii actually had the XX?)

Merlin XXX = Merlin 30 (Arabic numerals were used past XX/20). That was - as it was the case with Merlin VIII on the Mk.I - a low altitude engine. Good for easy taking off from a carrier, bad for actual air combat. 1300 HP was available at sea level with a lot of ram (without ram effect power was 1275 at SL), further up the power went down.
Merlin XX was making 1300 HP at about 13-14 thousand feet, where Merlin 30 was making ~800 HP.

As for altitudes? I don't think it does get such a bad rap on that basis tbh. It was specifically designed to operate at low to medium altitudes as part of its role and specification. It was never really intended to be an interceptor - it was principally and observer aircraft with fighter capability. It was not envisaged to be operating within the range of land-based aircraft and was intended to be a bomber destroyer. Aircraft operating over the med were usually going to be operating fairly low level and the Fulmar ii was pushing out its theoretical best of 272mph at around 7000ft which put it at less disadvantage than anywhere else at least!

Bombers will try to fly and fight at their best altitude, that is 13000-15000 ft, depending on the bomber (Ju 88 and 87, He 111, most of Italian stuff that was not carrying torpedoes). Fulmar was also lacking in ability to down half-decent enemy recon aircraft shadowing the fleet.

However, given that the Blenheim was the only regular day light flying RAF bomber by the end of 1940 and into 41 - and carried a mere 1000lbs of bomb-load, I'm still pondering what raids this long-range escort fighter would be protecting in the early years of the war...

Wellingtons and Hampdens flying combat missions during the night was a consequence of RAF not having escort for their bombers. Provide the effective escort and these two bomber types can wage the war during the daylight.