Would a Spitfire with the same wing area as on the Bf 109 have been a good idea or not?

[Admiral Beez]

There are a few ww2 piston-engined, monoplane, single-engined fighters with wing areas similar to the Bf 109's 16 sqm. These include the Macchi C.202 Folgore (16.8 sqm) and even smaller, the Yakovlev Yak-3 (14.9 sqm). What do we think of putting the Yak-3 wing onto a Spitfire?

 

[GregP]

But if top speed was "VERY" rarely used and "NOBODY" flew "NEAR" it and it consumed such a "LOT" of fuel, why was it at the top of the list on both the British and German procurement specifications at the time? Why did both Supermarine and Messerschmitt chase top speed with the Spitfire and Bf 109? What were they missing?

Why did they insist on putting bigger and bigger more fuel guzzling engines on their airplanes if top speed was not important? And yes, bigger engines do improve climb rate as well, but top speed was at the top of the list. It actually moved there from being of lower priority than climb, but both the Luftwaffe and RAF were chasing top speed in these designs. They topped their wish list with it.

Seriously: Why the longwinded explanation that most pilots did not fly around at top speed all the time and and that top speed is rarely used? You even list why it (top speed) is important yourself: Because you need it to either attack or disengage. Of course you don't do that all the time, but when you do want to catch an opponent or escape, you want every km/h or mph you can squeeze out of your ride. In addition, reducing the wing size on the Spitfire will also make it lighter and climb faster.

Not sure where you are going with this: The premise here was if reducing the wing size on the Spitfire Mk I would make it better worse aircraft compared to the Bf 109E. Everyone here seems to agree it would have made it faster, but you make a long winded argument that top speed is unimportant because it's so rarely used? Que?

Procurement specifications very rarely ever come from queries of the current pilots. They are made up by a commtiiee or committees consiting of older Air Force people from 2 or more earlier generations of pilots and other officers. They rarely address what the current pilots want.

That comes from working in the industry for 20 years before leaving the military weapons industry for commercial electronics. The specs for aircraft come from whatever the research agencies make advances in more than from what is actually needed.

Just my experiences talking there. The truth. if different from above, may be worse, but I have no proof it is.

 

[Reluctant Poster]

Wings on the Mk.III were just the clipped Mk.1 wings, not the new wings' type. Basically the same wings were very successful on many Spitfires produced.
Dowding objected that such a Spitfire will look too much like the Bf 109, leading to the friendly fire accidents. Wing loading was also greater, especially now that the engine in the nose is heacier, and the wing area is lower. So they retrofitted the normal wingtips.

According to Price in "The Spitfire Story " the Mk III was refitted with Mk !a wings. From my reading of Morgan and Shacklaldy the original wing had the revised undercarriage that was introduced to production on the universal C wing as well as a revised radiator.
The Spitfire story also includes a AFDU comparison of 2 VBs. They were selected to be as identical as possible. One was clipped and the other remained standard. The tests were repeated with the pilots trading paces. Then the clipped one was reverted to standard and the other was clipped and the tests were repeated. Again the testes were repeated with the pilot exchanged.

At 10,000 feet the clipped wings were about 5 mph faster
At 15,000 -20,000 feet No measurable difference
Above 20,000 the Standard Spitfire is slightly faster.
From 10,000-15,000 feet there is no difference in climb
In zoom climbs from 20,000 to 25,000 feet the standard Spitfire is 15 seconds faster
That last one is important. Rate of climb is very important in making successful intercepts. The slow climb rate of Wildcats resulted in a few failures to intercept in the carrier battles of 1942
The increased speed at lower altitude was irrelevant as the Battle of Britain was fought at higher altitudes.

Also I'm wondering how 8 machine guns are going to fit into that little wing.

 

[GregP]

According to Price in "The Spitfire Story " the Mk III was refitted with Mk !a wings. From my reading of Morgan and Shacklaldy the original wing had the revised undercarriage that was introduced to production on the universal C wing as well as a revised radiator.
The Spitfire story also includes a AFDU comparison of 2 VBs. They were selected to be as identical as possible. One was clipped and the other remained standard. The tests were repeated with the pilots trading paces. Then the clipped one was reverted to standard and the other was clipped and the tests were repeated. Again the testes were repeated with the pilot exchanged.

At 10,000 feet the clipped wings were about 5 mph faster
At 15,000 -20,000 feet No measurable difference
Above 20,000 the Standard Spitfire is slightly faster.
From 10,000-15,000 feet there is no difference in climb
In zoom climbs from 20,000 to 25,000 feet the standard Spitfire is 15 seconds faster
That last one is important. Rate of climb is very important in making successful intercepts. The slow climb rate of Wildcats resulted in a few failures to intercept in the carrier battles of 1942
The increased speed at lower altitude was irrelevant as the Battle of Britain was fought at higher altitudes.

Also I'm wondering how 8 machine guns are going to fit into that little wing.

Correct me if I'm wrong, but wasn't the clipped-wing Spitfire made to be better specifically at lower-altitude tasks?

It was never intended for 25,000-foot missions. But, when tghe need arises, you fly what you are issued on whatever mission comes up.

 

[tomo pauk]

Also I'm wondering how 8 machine guns are going to fit into that little wing.

There were Spitfires tested with 4 cannons and two LMGs, so I'd say that just 8 LMGs would've fit in.

That last one is important. Rate of climb is very important in making successful intercepts. The slow climb rate of Wildcats resulted in a few failures to intercept in the carrier battles of 1942

Wildcat, especially in the -4 flavor, have had a low rate of climb because it was a heavy and draggy aircraft, with an outdated engine for 1942. There is no wing surgery (that still leaves it with 6 LMGs and folding wing ability) that can help it.
The inexperience of the fighter control officers was also to blame for the inability to intercept, and we can also recall that even the Zeros had no luck in intercepting the inbound bombers.
Lastly, German bombers of the BoB era were not flying at 25000 ft; even 20000 ft was pushing it.

 

[Holtzauge]

Procurement specifications very rarely ever come from queries of the current pilots. They are made up by a commtiiee or committees consiting of older Air Force people from 2 or more earlier generations of pilots and other officers. They rarely address what the current pilots want.

That comes from working in the industry for 20 years before leaving the military weapons industry for commercial electronics. The specs for aircraft come from whatever the research agencies make advances in more than from what is actually needed.

Just my experiences talking there. The truth. if different from above, may be worse, but I have no proof it is.

I agree that that's probably quite true. The specifications were not written by active pilots themselves, but since a specification has to pass many eyes before the manufacturer gets it, you would think it would be consistent (right or wrong) with whatever tactical ideas the Air Force in question has. In fact, both the German and British specifications changed the top order of priority from climb to speed just as the Spitfire and Bf 109 were being developed.

Regarding weaponry, I write about that in my book, and the Spitfire originally was designed for 4, then 6, and finally 8 guns, and the upgrade for 6 to 8 guns came about when Sqdr L Sorley visited Supermarine and asked Mitchell if it was possible to bring the Spitfire in line with the latest 8 gun requirement, to which Mitchell replied that this could be done provided the requirement to carry four 20 lb bombs (IIRC) was dropped and it was OK to lessen the internal fuel carried somewhat.

Correct me if I'm wrong, but wasn't the clipped-wing Spitfire made to be better specifically at lower-altitude tasks?

It was never intended for 25,000-foot missions. But, when tghe need arises, you fly what you are issued on whatever mission comes up.

Yes, that's what I believe as well, and I also think that it was done to improve the roll rate (which it did in a big way) because the RAF was concerned with the Fw 190's outstanding performance in this regard.

 

[Holtzauge]

There are a few ww2 piston-engined, monoplane, single-engined fighters with wing areas similar to the Bf 109's 16 sqm. These include the Macchi C.202 Folgore (16.8 sqm) and even smaller, the Yakovlev Yak-3 (14.9 sqm). What do we think of putting the Yak-3 wing onto a Spitfire?

View attachment 857601

Well from a theoretical perspective, if one has ease of production in mind as well as aerodynamic efficiency, I think the P-51's and Bf 109's planforms are better: The Bf 109's wing did not incorporate wash-out, but it still has a nice high aspect ratio, and the P-51 when you add the effects of wash-out gets quite close to an elliptical lift distribution.

The Yak-3 on the other hand, even if it did not incorporate twist, has much of the wing area concentrated to the centerline and thus deviates more from an elliptical lift distribution. And if twist was added, well then it would deviate even more from the elliptical.

Maybe someone knows why they went with the triangular wing shape on the Yak-3? The only reason I can think of is that it meant less weight since it lowered the bending moments in the wing spars.

 

[tomo pauk]

Well from a theoretical perspective, if one has ease of production in mind as well as aerodynamic efficiency, I think the P-51's and Bf 109's planforms are better:

Ease of the production of the 109 and P-51 had a lot to do with the production method. Supermarine used the built-up method, where the ribs were made from several individual pieces. MTT and NAA used the 1-piece ribs. Add there the fuselage frames also being the built-up pieces, and the manhours needed for the Spitfire went through the roof.

MiTasol - please correct me here if I'm wrong.

 

[Holtzauge]

According to Price in "The Spitfire Story " the Mk III was refitted with Mk !a wings. From my reading of Morgan and Shacklaldy the original wing had the revised undercarriage that was introduced to production on the universal C wing as well as a revised radiator.
The Spitfire story also includes a AFDU comparison of 2 VBs. They were selected to be as identical as possible. One was clipped and the other remained standard. The tests were repeated with the pilots trading paces. Then the clipped one was reverted to standard and the other was clipped and the tests were repeated. Again the testes were repeated with the pilot exchanged.

At 10,000 feet the clipped wings were about 5 mph faster
At 15,000 -20,000 feet No measurable difference
Above 20,000 the Standard Spitfire is slightly faster.
From 10,000-15,000 feet there is no difference in climb
In zoom climbs from 20,000 to 25,000 feet the standard Spitfire is 15 seconds faster
That last one is important. Rate of climb is very important in making successful intercepts. The slow climb rate of Wildcats resulted in a few failures to intercept in the carrier battles of 1942
The increased speed at lower altitude was irrelevant as the Battle of Britain was fought at higher altitudes.

Also I'm wondering how 8 machine guns are going to fit into that little wing.

Interesting data, and seems consistent with what one would expect: Clipping the wing reduces the wetted surface which at low lift coefficients means less drag. However, at higher altitudes the wing loading and aspect ratio starts to become important which would favour the ordinary Spitfire wing since the clipped wing is not very efficient from an induced drag perspective.

Regarding the theoretical Spitfire Mk IM however, this not only reduces the wing area, but redistributes it leading to a more efficient wing. And I do agree with you regarding fitting in the guns, landing gear and other equipment, and that this would have been difficult. However, from what we know of Mitchell I think he would have gone for an aircraft closer to the Mk IM than the Mk I if he had had the chance to do that. Remember the the Spitfire was already pushing the envelope in that it came close to being struck from further consideration for not fulfilling the 60 mph landing speed (I write more about this in my book).

 

[Holtzauge]

Ease of the production of the 109 and P-51 had a lot to do with the production method. Supermarine used the built-up method, where the ribs were made from several individual pieces. MTT and NAA used the 1-piece ribs. Add there the fuselage frames also being the built-up pieces, and the manhours needed for the Spitfire went through the roof.

MiTasol - please correct me here if I'm wrong.

This is true, and in my book I actually have a whole chapter devoted to production costs. And as you say, the Spitfire does not seem to have been designed for ease of production to the same extent as the Bf 109.

I have tried to compile data on this in my book, which is difficult seeing the British and Germans seems to have different ways of calculating and that some German figures do not include sub-contracted parts.

But in summary, my estimate lands at the Spitfire requiring roughly about 1.5 times the manhours to produce compared to what the Bf 109 did. But that is not a number I will defend here (because I would then basically have to post the whole chapter), so if you want to know how I arrived at that number you will have to buy my book!

 

[Shortround6]

Spitfire was 13% but since the wing had a long cord that meant the wing was still fairly thick in actual inches/cm. Mustang had thicker wing in percentage.

Now one can see that they didn't really redesign the wing to fit in the extra 1 or 2 guns on each side. That is to say they did not design a gun bay that would hold 4 guns like the Hurricane. They sort of just jammed the extra guns in-between the existing rib spacing and arranged the ammo to suit. This also spread the weight out along the wing and while it helped with the span loading it may not have helped the roll response any but then that last .303 gun is not very heavy.

If you are designing a totally new wing there is no reason to keep the original gun spacing to hold 6-8 .303s. Trying to fit Hispano guns in the wings get harder, not impossible but harder. Spanish did just stick Hispano guns in a 109 wing. They redesigned that area of the wing to hold the Hispano gun including fitting a new short spar or bulkhead to mount the gun after they made a rather large hole through the replacement spar.
Since you have to fit the guns outside the wheel wells actual space inside the wing starts to get tight.

 

[Holtzauge]

View attachment 857641
Spitfire was 13% but since the wing had a long cord that meant the wing was still fairly thick in actual inches/cm. Mustang had thicker wing in percentage.

Now one can see that they didn't really redesign the wing to fit in the extra 1 or 2 guns on each side. That is to say they did not design a gun bay that would hold 4 guns like the Hurricane. They sort of just jammed the extra guns in-between the existing rib spacing and arranged the ammo to suit. This also spread the weight out along the wing and while it helped with the span loading it may not have helped the roll response any but then that last .303 gun is not very heavy.

If you are designing a totally new wing there is no reason to keep the original gun spacing to hold 6-8 .303s. Trying to fit Hispano guns in the wings get harder, not impossible but harder. Spanish did just stick Hispano guns in a 109 wing. They redesigned that area of the wing to hold the Hispano gun including fitting a new short spar or bulkhead to mount the gun after they made a rather large hole through the replacement spar.
Since you have to fit the guns outside the wheel wells actual space inside the wing starts to get tight.

Yes, while certainly more challenging to fit the guns into a smaller wing, I think it could be done as well. Especially if one was to go with the same wing profile as on the Bf 109, the NACA 2R1, or even better, the NACA 230-series. In addition, the big gain with a smaller wing area comes from the drastically reduced wetted surface, and even of you had to add a few fairings I think the end result would still have been a significantly faster, and somewhat lighter aircraft.

 

[GrauGeist]

Before changing the wings to enhance speed, perhaps moving the radiators to a housing based on the P-51's configuration?

Even Willy Messerschmitt tried to address the wing-mounted radiators issue with a ventral radiator on Bf109 V31.

 

[GregP]

I agree that that's probably quite true. The specifications were not written by active pilots themselves, but since a specification has to pass many eyes before the manufacturer gets it, you would think it would be consistent (right or wrong) with whatever tactical ideas the Air Force in question has. In fact, both the German and British specifications changed the top order of priority from climb to speed just as the Spitfire and Bf 109 were being developed.

Regarding weaponry, I write about that in my book, and the Spitfire originally was designed for 4, then 6, and finally 8 guns, and the upgrade for 6 to 8 guns came about when Sqdr L Sorley visited Supermarine and asked Mitchell if it was possible to bring the Spitfire in line with the latest 8 gun requirement, to which Mitchell replied that this could be done provided the requirement to carry four 20 lb bombs (IIRC) was dropped and it was OK to lessen the internal fuel carried somewhat.



Yes, that's what I believe as well, and I also think that it was done to improve the roll rate (which it did in a big way) because the RAF was concerned with the Fw 190's outstanding performance in this regard.

That;s my understanding as well. The Spitfire was good at a lot of things, but quick roll response was not one of them.

 

[Holtzauge]

Before changing the wings to enhance speed, perhaps moving the radiators to a housing based on the P-51's configuration?

Even Willy Messerschmitt tried to address the wing-mounted radiators issue with a ventral radiator on Bf109 V31.

Yes, the radiator installation on the Bf 109 (and the Spitfire for that matter) were actually not very efficient designs. Both of them suffered from boundary layer ingestion and flow separation in the diffusor channel. The Spitfire probably to a lesser degree since the expansion in the diffusor was less, and since the Spitfire had a high pressure radiator system which the Bf 109 did not (I cover how much better the Bf 109 E would have been with that in my book). The P-51 really set the state-of-the-art though, both in terms of the intake being out of the boundary layer and with a good diffusor design. The only alternative radiator system that come close to being as efficient as on the P-51 are radiators mounted in the nose like on the Fw 190 D9, Ta 152 and Centaurus powered Tempest etc.

 

[z42]

Before changing the wings to enhance speed, perhaps moving the radiators to a housing based on the P-51's configuration?

Might require a time machine? Yes, Merediths paper was published when the Spit was designed, but the P-51 installation apparently took a lot of work to get right. Then again, if we're aiming for better than the historical Spit rather than matching the P-51, it gets more feasible I suppose. Would probably require moving the wing backwards to maintain CG.

Alternatively, keep it simple and slot in a Lancaster style UPP with a chin radiator. (might also require moving the wing).

 

[MiTasol]

Ease of the production of the 109 and P-51 had a lot to do with the production method. Supermarine used the built-up method, where the ribs were made from several individual pieces. MTT and NAA used the 1-piece ribs. Add there the fuselage frames also being the built-up pieces, and the manhours needed for the Spitfire went through the roof.

MiTasol - please correct me here if I'm wrong.

You are correct about NAA and the Spitfire. I do not know about the 109 as I have never worked on one and have no manuals for the 109 on hand (I am not at home at present).

 

[GrauGeist]

You are correct about NAA and the Spitfire. I do not know about the 109 as I have never worked on one and have no manuals for the 109 on hand (I am not at home at present).

Willy tried to keep the Bf109's construction simplified, including the engine mount integral with the landing gear assembly (which led to the splayed geometry and subsequent taxi issues).

 

[frankv]

The Spitfire was designed as a short-range interceptor, so its rate of climb (2-3,000 fpm in early variants) was more important than outright speed. It needed to get to the altitude of incoming bombers and their escorting fighters in the time given by radar and Observer Corps alerts.

Exceptions to this would be the reconnaissance versions, which I guess could climb more leisurely, but wanted to get even higher.

I suspect that increasing the wing loading by reducing the wing area would have reduced the rate of climb and/or service ceiling.

 

[Shortround6]

I suspect that increasing the wing loading by reducing the wing area would have reduced the rate of climb and/or service ceiling.

Planes climb better with smaller wings, less drag.
On the other hand, Ceiling is a lot more wing loading dependent.
Absolute ceiling is the altitude the plane can fly at while going dead level with no bank.
The plane cannot any faster, it has no more power. If it had power it could climb, even slowly.
It cannot fly any slower or it stalls, spins and looses a great deal of altitude.
Plane is flying at the speed where the wing can generated enough lift to keep the plane in the air.
Using a smaller wing means you can fly a little faster but can the smaller wing generate enough lift while flying a little faster.