Would a Spitfire with the same wing area as on the Bf 109 have been a good idea or not? (4 Viewers)

[Geoffrey Sinclair]

AVIA 6/10393 Effect of Equipment on Spitfire Top Speed, Calculated Corrections at 360 mph, difference between ideal and variation

Equipment	Ideal Condition	Variation	Correction mph
Exhausts	Multi Ejector	Original Mk I	5.25​
Exhausts	Multi Ejector	Triple Ejector+Fishtail	7.75​
Exhausts	Multi Ejector	Triple Ejector+Fishtail+Gun Heating	9​
Air Intake	No snowguard	Guard fitted	8.5​
Air Intake	No stoneguard	Guard fitted	7.5​
Windscreen	Conical	Internal bullet proof	4​
Windscreen	Conical	External bullet proof	7.75​
Rear View Mirror	None	Faired	3.5​
Rear View Mirror	None	Unfaired	6.75​
Radio Mast	None	Standard	1.5​
Radio Mast	None	Whip	0.75​
Armament	No protruding cannon	Two cannon	6.25​
Armament	No protruding cannon	Two cannon+2 stubs	8.5​
Cannon fairing bulges	None	Small	0.5​
Cannon fairing bulges	None	Large	1.5​
Ejector chutes	Flush cut	Projecting from wing surface	1.25​

Spitfire V EN946

Equipment	Original	Final	Correction mph
Exhausts	Triple Ejector+Fishtail	Multi Ejector	7.75​
Air Intake	External snowguard	Removed	8.5​
Rear View Mirror	Rectangular unfaired	Circular faired	3.25​
Radio Mast	Standard	Whip	0.75​
Ejector chutes	Projecting	Cut Flush	1.25​
Total Above	All	All	21.5​
Finish	Ex Factory	Smooth	8.5​

Total projected increase in speed 30 mph, measured increase 30 mph

Speeds in mph assuming modifications done. NOTE: Ideal speed aircraft would NOT be combat worthy.

Aircraft	As tested	Ideal speed, normal finish	Ideal speed and finish	Equipment Effect	Finish Effect
Prototype Mk I	367​	383​	383​	16​	0​
Production Mk I	357.7​	378.7​	383​	21​	4.3​
Early Mk V + AB873	371.5​	405.3​	407​	33.8​	1.7​
Late Mk V except AB873	356.3​	395.8​	407​	39.5​	11.2​
Mk V EN946	388​	407​	407​	19​	0​
Prototype Mk IX	414​	438​	445​	24​	7​
Production Mk IX	403.7​	436.3​	445​	32.6​	8.7​

Spitfires listed as tested, prototype K9793, Mk I N3171, X4257, K9787, Mk V K9788, N3053, X4922, W3134, AA787, AA937, AB873, EF644, EN946 (original and RAE modified), Mk IX N3297, BF274, JL227, EN498

Various parts A&AEE report 692
RAE Technical Note Number Aero 1217 (Flight) June 1943, Improvement of performance of Spitfire EN946
RAE Technical Note Number Aero 1246 (Flight) July 1943, Comparison of three production Spitfires

 

[spicmart]

Blasphemy! Heresy! There's no such thing as an 'unattractive Spitfire' (Don't weaken my flawless argument by bringing up the post-war trainer conversions, please....). 'Unattractive Spitfire' is the dictionary definition of an oxymoron. Possibly. Well, it should be

For my taste, the only flawlessly (!) attraktive Spitfires are the Mk. XIV (razorback and bubble canopy version) and, even more so, the Mk. 21/22 with its slightly different wings.
All others had some aesthetical deficiency in one way or the other, e.g. unattractive vertical stabilizer shapes, supercharger inlet directly behind (underneath) the propeller.
Most Merlin Spits look snub-nosed, especially the early variants, which sucked aesthetically, imHo. There you have it.
Incoming..

 

[Reluctant Poster]

The Consolidated P-30 would like to have a word...

I had thought about it but discounted at as a two seater.

 

[Reluctant Poster]

For my taste, the only flawlessly (!) attraktive Spitfires are the Mk. XIV (razorback and bubble canopy version) and, even more so,the Mk. 21/22 with its slightly different wings.
All others had some aesthetics deficiency in one way or the other, e.g. unattractive vertical stabilizer shapes, supercharger inlet directly behind (underneath) the propeller.
Most Merlin Spits look snub-nosed, especially the early variants, which sucked aesthetically, imHo. There you have it.
Incoming..

I agree with the slight change that the Seafire Mk XV looks the best because of its slightly shorter nose ( single stage Griffon)

 

[spicmart]

I agree with the slight change that the Seafire Mk XV looks the best because of its slightly shorter nose ( single stage Griffon)

The Seafire Mk. XV still passes with flying colours.

 

[Shortround6]

I had thought about it but discounted at as a two seater.

Well, if they are making a retractable landing gear monoplane with an enclosed canopy 2 seat fighter how far behind is a retractable landing gear monoplane with an enclosed canopy single seat fighter? a few weeks, a few months, more than a year?

 

[Reluctant Poster]

Well, if they are making a retractable landing gear monoplane with an enclosed canopy 2 seat fighter how far behind is a retractable landing gear monoplane with an enclosed canopy single seat fighter? a few weeks, a few months, more than a year?

You have to define they. In real life Consolidated did make an unsuccessful 1 single seat version but never did much after that in the fighter field. It seems they didn't consider it worth the effort to develop a proper single seater.

 

[Shortround6]

You have to define they. In real life Consolidated did make an unsuccessful 1 single seat version but never did much after that in the fighter field. It seems they didn't consider it worth the effort to develop a proper single seater.

The US in general or even other nations. Consolidated moved factory locations in the mid 30s and was getting a lot of contracts for the PBY series which gave them steady income and funded expansion. Perhaps staying in the fighter field was seen as too risky.
The P-30 would have needed extensive modifications to be a single seat fighter. the wing was too big compared to the Curtiss and Seversky competition. And due to it's size, it was too expensive. And Consolidated needed to change engines. The USAAC was trying to get away from the Curtiss V-12s and the only engines in sight were the Wright R-1820 and P&W R-1830 and this point in time the R-1830 was an 800hp engine.

As shown, several countries were making retracting landing gear, monoplane enclosed canopy transports.
None of this was patented. It was just part of natural progression. The US had at least one requirement for a single seat fighter that called for an enclosed canopy to protect the pilot from a 250mph slipstream. Plane may not have hit 250mph but they were thinking about it. The need for retractable landing gear for reduced drag had been demonstrated. The Japanese fought against that one for several years (light weight and lack of industry to make large numbers of retracting landing gear?).

The I-16 also shows that sometimes the idea doesn't always met expectations. It is easy to say "enclosed cockpit". It was lot harder to do. The idea is for the transparent panels to not hinder vision too much, which calls for high quality manufacturing of the transparent material. It also means that since the pilot cannot stick his arm out with a rag to clean off oil spray they have to get better at stopping oil leaks on the engine. Russians were not the only ones who had problems with either one or both problems.
The Monoplane was low drag, it was also, if small, low lift which meant high landing speeds. Which meant flaps in the early/mid 30s and while flaps went through a huge advance in just 10 years things were rather dicey in the early/mid 30s. First P-26s were landing at about 80mph. The Supermarine 224 was turned down, in part, because it landed at about 60mph instead of the desired 50mph. 16 years after WW I and the RAF wanted a fighter than landed only little faster than Sopwith Camel.
Many of the 1930s fighters used the pilots arm to power the retracting landing gear. So again, claiming firsts is important but many times first were not being used in many of the planes being built in 1942 and later.

 

[GrauGeist]

I had thought about it but discounted at as a two seater.

Retractable gear, enclosed and heated cockpit and a turbo-supercharged engine was fairly advanced for the day - and they did trial a single-seat version, too.

 

[PAT303]

The Seafire Mk. XV still passes with flying colours.

 

[NZTyphoon]

For my taste, the only flawlessly (!) attraktive Spitfires are the Mk. XIV (razorback and bubble canopy version) and, even more so, the Mk. 21/22 with its slightly different wings.
All others had some aesthetical deficiency in one way or the other, e.g. unattractive vertical stabilizer shapes, supercharger inlet directly behind (underneath) the propeller.
Most Merlin Spits look snub-nosed, especially the early variants, which sucked aesthetically, imHo. There you have it.
Incoming..

 

[drgondog]

I was tempted to engage, but the boundary conditions are too vague. For example:

1. Reduced area Spitfire wing = Bf 109 = 172sf?
2. New wingspan the same and equal to 32 ft? Even with elliptical wing scaled vs trapezoidal wing of the 109? This has aspect ratio and induced drag implications. For example, the same span with an elliptical planform suggests greater MAC which would reduce Aspect Ratio but still also might reduce induced drag (theoretically, but low probability) compared to the 109 depending on Oswald value comparisons. Not much implication for top speed comparison, but important for lower speed turn and climb. Also increased MAC has direct impact on base Reynolds number comparisons.
3. Gross weight reduction estimate for the projected wing weight reduction? While reducing the wing area is given to equal to the 109, the span and planform have implications toward weight reduction. I would say offhand, 'very little' with comment that wing loading due to the area reduction was far higher contribution to the performance discussion.
4. While wetted area is very important, the greatest contribution is toward friction drag, which is optimally lowest with very smooth wind tunnel data results. While the Spitfire surface quality was not up to Mustang standards, the 109 friction drag in real life (according to Hoerner) was notoriously bad. A combination of surface quality (both production quality and paint), airfoil parasite drag and gap parasite drag. What do you propose as the CDparasite drag delta for the new Spitfire wing - and why? What do you propose as CDparasite drag (base) for the 109? Hoerner values?
5. Which engine and engine power combinations are you proposing for both fighters?
6. What CL are you proposing for both at Stall, Cruise and Top Speed for both wings? A direct scale decrease based on reduced AR for new Wing?

I question whether the 109 wing had lower drag than the NACA 2213 in compressibility range - huge discussion relative to CDmach at top speed. What sources do you have?

Nevertheless an interesting post.

 

[Shortround6]

Drgondog brings up a number of good points.

different point/s

There seem to be 2 schools of thought on wing size for fighters. Perhaps accidental or perhaps driven by common solutions to common goals?

French, Germans, Italians and Russians seem to favor wings in the 170-185 sq ft area (give or take) while the Americans, British and Japanese favored larger wings. Around 220-260 sq ft on the late 30s planes. Japanese used 192-200sq ft on the fixed landing gear 700-750hp fighters.

The 1930s saw a lot of development in high lift devices so even 1-2 years can make a difference in choices. And what was thought at certain times may not be what we think looking back. The slats of the wing of the 109 were hardly "new" although perhaps their use in combat maneuvers was. The Slats were a Handley Page patent (with a German) and were used on many, many aircraft in the 20s and 30s, even the first 50 Halifax bombers
Primary purpose was to retain aileron control just before or during the stall to prevent spins and/or one side of plane dipping and cartwheeling the pane while landing.
Some people (designers) tried to get the same results a different way so they would not have to pay royalties.
It was found that extended the span of the slats/slots to nearer (or even full) span gave lower stall speeds but that was only had the higher angle of attack.
The slats/slots were not "free" in relation to drag. Some planes were better than others but the fit of the slats/slots sometimes cost a few mph and depending on the exact design the linkage (often external on 1920s and early 30s designs) also cost speed.

As far as flaps go, I have already mentioned the P-26.

They were either up or down (same as Spitfire) and were more of a drag flap (air brake) than a lift device. Early P-26s did not have flaps and landed at 80mph. A very scary thought in the early 30s on grass airfields. The flaps brought the speed down to 72mph and most (all?) of the early production planes were refitted and all planes still under construction or on order were completed with the flaps. 72mph was still a scary speed on a early 30s airfield. Other countries had their own time lines for flaps. For the British the first two RAF service airplanes with flaps were the Avro Anson and the Gladiator.
Use of flaps in combat requires flaps that do not go to max defection when activated (assuming power activation) but power flaps require power (hydraulic, electric or pneumatic) and many mid 30s designers were not happy about adding weighty systems to light weight fighters. Early Spitfires required the pilot to hand crank the landing gear up and down.
Many flaps were designed only to be used a low speeds, like around 150-200mph but flaps that could be lowered only small amount (15 degrees or less? ) might be able to used at higher speeds. Japanese seem to have limited their "combat" flaps to 8 degrees and since they were a type of Fowler flap they extended rearward before/as they lowered adding the wing area in addition to changing the airfoil or lift of the existing wing area.
Bf 109 could use 5 or 10 degree flap settings in combat but that added drag and the pilots needed to be careful. They were also manual, controlled by a hand wheel so one more thing for the pilot to try to do in a turn, Pull 3-4 "G" fly the plane with one hand while operating the flap control wheel with the other and trying not to let the arm motion of the arm controlling the flap transfer through the body to the control stick.

The Spitfire and Hurricane were designed to get out and into existing RAF fighter fields while carrying over 3 times the weapons load of any service RAF fighter before the Gladiator and almost double the armament weight of the Gladiator.
Now in comparison the
Americans were asking for about 1/2 -5/8ths the armament weight (P-35/P-36)
The Japanese were asking for about 1/4-3/8s the weight. (2 RCMG plus ammo)
The Soviet I-16 was around 1/4-3/8ths the weight. (2 RCMG plus ammo).
The Italians were asking for about 3/4 the weight (two 12.7mm guns)
The French were asking for about 3/4 the weight (one 20mm and two 7.5mm).
Germans asked for the standard world standard 1/4-3/8s the weight. (2 RCMG plus ammo)
Germans asked in the first specification for the two 7.9mm mg OR a 20mm cannon, not both, that came a bit later.
Wing size/loading was not just dependent on armament. Engine and fuel capacity were also important.
French were using an engine that was about 200-250lbs lighter than the British.
Italian radial was almost as heavy but didn't have several hundred pounds of coolant and radiator.
Soviet I-16 used a lighter air cooled radial.
Americans were using lighter air cooled radials in the mid 30s.
Japan in the mid 30s were using very light radials
Germans were using the Jumo 210 that was over 300lbs lighter. Early 109s held around 270 liters of fuel.
In fact a 109 C or D weighed 2160kg (4762lb) and landed (not stall) at 111kph (69mph).
It's "small" wing is perfectly understandable for a plane of it's weight and power (engine and fuel weight).

Now by most estimates/counts the Germans built over 1000 Jumo powered 109s. So claims that the 109 was "designed" for the DB 600 series of engines will be looked at skeptically.
They were stuffing DB 600 engines into He 111 in 1936, at least for test, around 1 to 1 1/2 years before a 109 got any sort of DB 600 series engine.

Trying to design a Spitfire in 1935-36-37 using a Merlin sized engine and 380-390 liters of fuel and the eight .303s and 2400 rounds of ammo using a 170-180 sq ft wing was going to be very difficult trying to get the required field performance. Or a much more complicated wing (much more complicated flap set up + stats?).
Plane of about the same wing loading as a Bf 109D that weighed as much as a Spitfire I (without armor or protection) would need a wing of around 195-200 sq ft.

Added. The Germans built 109Ds in 7 different factories. Major revisions to the design, like a new wing, might well an outweighed any performance advantage it may have had at this point.
British had ordered a Spitfire with a pair of 20mm guns in 1939, They trialed a Spitfire I with two 20mm guns and four .303s in the Winter of 1940 at a weight of 6385lbs.
The "B" wing was supposed to hold the 20mm guns (with drums) and the four .303s and this may have been the last chance to shrink the wing. Any further changes to the wing just asked for even a large weight in guns/ammo increasing the wing loading and pushing the weight into the catagory of a 109G and the 109G is usually known to have passed the peak of 109 development.

 

[Holtzauge]

drgondog and S Shortround6 : Check your PM's pls.

 

[SaparotRob]

drgondog and S Shortround6 : Check your PM's pls.

I just noticed your signature line.