Biggest speed increase within type?

fastmongrel said:

The 1st production version of the Fiat G50 with an 875 hp radial had a top speed around the 290 to 300 mph range. The Fiat G56 prototype which apart from the obviously different engine (it was fitted with the DB 603) looked identical and was reckoned to be good for 440 mph. Obviously the G56 was a prototype but it nearly got into production before events overtook it.

Someone else who isnt a mathematical idiot will have to do the sums for me its too cold to take my socks off.

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I admire your spunk, but it would be difficult to make the argument that the G50 shared much with the G55/56 series other than a common manufacturer. Not only did the engine change (no big problem), but the basic aircraft structure did (big problem) and these changes were more than what was necessary simply to mate a G50 airframe to a DB engine.

What about the MC200 to MC205 progression? Much more than the Fiats, this might reasonably be considered the gradual development of the same basic airframe.

Still probably doesn't equal the Bf-109, though

zoomar said:

I admire your spunk, but it would be difficult to make the argument that the G50 shared much with the G55/56 series other than a common manufacturer. Not only did the engine change (no big problem), but the basic aircraft structure did (big problem) and these changes were more than what was necessary simply to mate a G50 airframe to a DB engine.

What about the MC200 to MC205 progression? Much more than the Fiats, this might reasonably be considered the gradual development of the same basic airframe.

Still probably doesn't equal the Bf-109, though

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The Bf109A compared to the Bf109K has a completely different airframe, they look similar but are not the same aircraft. I cant see any difference comparing the 109 series to the Fiat G series the Supermarine Spitfire series or the NA Mustang series for example.

when did the first 109s enter service, 1935-1937?

It was a sleek design from the beginning and not much needed modification to get a bigger engine in it, however, there were parts better developed for those new high speeds and at higher altitudes.

I doubt you'd find other aircraft that come close to those figures seeing as most of them were faster out of the gate. The war was on, and benchmarks were set when developing an aircraft. In most respects if an aircraft wasn't up to par it never saw production anyway.

i've thought of a similar comparison of the P-35 into the P-47:
The P-35 started with a speed just over 300mph.
The P-43 achieved a top speed of 356mph
The early P-47s exceeded 400mph, while Bs and Cs managed over 420mph.
The P-47D managed to see gains over 430mph, and topping out above 440mph.
The introduction of the M engine enabled many aircraft in service to exceed those speeds. The actual M prototype tested at 488mph.
I think they sought to lower the drag profile with the J which achieved 507mph, but was later out shined by the P-72 which achieved 480 with out a turbocharger. Projections placed its top speed closer to 550mph.
A little incite reveals the R-4360 was also installed on a half dozen P-47s at a time when R-2800 was topping out around 3200hp.

Anyway, you take 300 from 550 and that gives about a 250 mph spread.
If you dont include the prototypes, then it ends up being closer to 200 mph.

the spread you gave the 109 was only 186mph and i dont even know that the 109H flew beyond prototypes.

I don't know if its a fair comparison, but you could also take the P-36 and measure its development into the P-40, in which the P-51 was born out of. I think you'd see similar speed spreads from those examples.
P-36 early prototypes flew at 281mph.
The fastest P-40s saw about 380mph.
while the development of the P-51 exceeded 400mph using the same power plant.
The P-51H saw speeds of 490mph.
Thats a speed spread of 209mph between the three war planes. Probably not as remarkable as the spreads achieved by Messerschmidt or Seversky aircraft, but none the less, the efforts of Curtiss also contributed a lot to the late Mustang.


I also have to question the instrumentation during the mid 1940s, particularly where the top speeds are above 450mph, and at higher altitudes. Its likely the measurements are a good 10-20mph uber, but if we are just looking at spreads, they probably all had the same level of error.


Bill

Lumping together P-35 P-47, and then P-36 P-51 hardly has anything to do with this thread.

tomo pauk said:

Lumping together P-35 P-47, and then P-36 P-51 hardly has anything to do with this thread.

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oh

sorry.


Bill

fastmongrel said:

The Bf109A compared to the Bf109K has a completely different airframe, they look similar but are not the same aircraft. I cant see any difference comparing the 109 series to the Fiat G series the Supermarine Spitfire series or the NA Mustang series for example.

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One may be able to draw a limit on the Spitfire. While the MK 21s and up are quite different the ones below the MK 21 may be much closer. As evidence of this we have either the remanufacture of airframes into later Mks or the conversion on the production lines. Some sources claim you can tell wither a MK XII with a Griffon engine started out as a MK V or IX or as a MK VIII by the tail wheel. MK VIIIs and planes derived from the MK VIII having retractable tail wheels.
I am not sure how much difference there is between a MK VIII and MK IX which was a MK V with the two stage Merlin stuffed in. In some cases literally, older airframes were re manufactured.

The Mustang is not so clear cut. Some here may be able to offer a much better opinion but it looks like there were 3 different Mustangs. The Allison powered originals, the Merlin powered ones with the 7 in splice in the depth of the fuselage but many other components staying the same. And the "H" which while retaining the pretty much the same external shape and aerodynamics used a totally new structure.

For the purpose of this discussion are we talking about planes that kept the same basic structure (changes in scoops or canopy's or wing tips not counted) or are we talking about planes that kept the same appearance or are we talking about planes from the same designer with little or nothing in common with their immediate preprocessor except the same general shape and signature on the drawings?
In my own opinion I would rule out the last but am open to the former situations.

fastmongrel said:

The Bf109A compared to the Bf109K has a completely different airframe, they look similar but are not the same aircraft. I cant see any difference comparing the 109 series to the Fiat G series the Supermarine Spitfire series or the NA Mustang series for example.

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All aircraft undergo some structural modifications to accept higher power engines and stresses. But the basic fuselage and wings of the Bf-109 underwent only progressive (and relatively minor) changes during the development of the aircraft. The Bf-109 K shares obvious structural and appearance similarities with Bf-109B. The G55/56 shares virtually nothing with the G50 in engine , basic structure, or outward appearance. If one accepted the G series, then it would make at least as much sense to include the Seversky/Republic P-35, P-43, P-47 series, or the Curtiss P-36, P-37, P-40, P-62 series.

Problem is, even if you do include the G series, or the others, the Bf-109 still takes the cake!

zoomar said:

All aircraft undergo some structural modifications to accept higher power engines and stresses. But the basic fuselage and wings of the Bf-109 underwent only progressive (and relatively minor) changes during the development of the aircraft. The Bf-109 K shares obvious structural and appearance similarities with Bf-109B. The G55/56 shares virtually nothing with the G50 in engine , basic structure, or outward appearance. If one accepted the G series, then it would make at least as much sense to include the Seversky/Republic P-35, P-43, P-47 series, or the Curtiss P-36, P-37, P-40, P-62 series.

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Is the statement in bold drawn out from a credible source or it's just an opinion? P-35 and P-47 are two worlds apart when we talk about basic structure engine.

Problem is, even if you do include the G series, or the others, the Bf-109 still takes the cake!

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Agreed.

zoomar said:

All aircraft undergo some structural modifications to accept higher power engines and stresses. But the basic fuselage and wings of the Bf-109 underwent only progressive (and relatively minor) changes during the development of the aircraft. The Bf-109 K shares obvious structural and appearance similarities with Bf-109B. The G55/56 shares virtually nothing with the G50 in engine , basic structure, or outward appearance. If one accepted the G series, then it would make at least as much sense to include the Seversky/Republic P-35, P-43, P-47 series, or the Curtiss P-36, P-37, P-40, P-62 series.

Problem is, even if you do include the G series, or the others, the Bf-109 still takes the cake!

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If we talk about a complete series of an aircrafts production yes the Bf109 takes the cake. However the Bf109B shared only a name and number with the totally different 109K. The 109K had a new wing, a different engine, different armament, different canopy, different tail and a similar looking fuselage which had a different method of construction and radically different aerodynamics. I am no expert but I imagine only standardised fittings and fastenings were the same between the 2 aircraft.

Wikipedia briefly mentions the changes in the aircraft the A to D were the same airframe, changes were made to the E to accomodate the heavier more powerful engine and later E versions had armament changes. The F was a major change with a new wing, fuselage tail and nose. The early G versions were similar to the F but incremental changes were made in the various sub versions. The K was another major change with a new wing and fuselage.

The 109 was 3 aircraft the A to E the F to G and the K with other prototypes, this is not a criticsm of the aircraft the 10 years from 35 to 45 was an astonishing period of change in aerodynamics a 109A even if it could have been fitted with a DB603 engine would have been dead meat in 1945 whereas the late G and K series were still astonishingly deadly fighters and with enough fuel and pilots the Luftwaffe could have made things extremely nasty for the allies in 1945.

I dont know enough about the Fiat G series to make claims about similarities or differences between the versions but looking at photos the planes from the firewall back look remarkably similar. More so than for example the early and late Spitfire versions.

Spitfire Prototype: 330 mph
Spitfire Mk I early: 372 mph
Spitfire Mk I 1940: 354 mph
Spitfire PR Mk XI: 426 mph (1.29 gain with Merlin engine, 96 mph gain)
Spitfire Mk XIV: 448 mph (1.36 gain with Griffon engine, 118 mph gain)
Spitfire F.21: 454 mph (1.38 gain with Griffon engine, new wing, 124 mph gain)
Spitfire F.21 prototype: 362 mph (1.4 gain with Griffon engine, new wing, 132 mph gain)

I've also seen numerous mentions of 460 mph as the top speed for the PR Mk XIX, but have seen no primary evidence to back that up.

There is the ultimate Spitfire, the Spiteful. 483 mph at 21,000 ft

Milosh said:

There is the ultimate Spitfire, the Spiteful. 483 mph at 21,000 ft

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I don't really consider the Spiteful a Spitfire.

In fact, I don't even really consider the F.21 a real Spitfire.

If you're going to argue for the Spiteful, then you could equally argue for the 590 mph capable Supermarine Attacker, as it was originally known as the 'jet Spiteful'.

Jabberwocky said:

I don't really consider the Spiteful a Spitfire.

In fact, I don't even really consider the F.21 a real Spitfire.

If you're going to argue for the Spiteful, then you could equally argue for the 590mph capable Supermarine Attacker, as it was originally known as the 'jet Spiteful'.

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With the fuzzy boundaries
that this thread is currently suffering, you may be wrong to; the Spiteful F.14 was no more than a laminar-flow wing attached to the fuselage of a Spitfire Mk XIV. A revised fuselage more pertinent to the Spiteful was developed later but the case in point is that the Spiteful, one step at a time, could be considered a development line of the Spitfire.

No, I don't think you could equally argue for the Attacker simply for employing the Spiteful's wing.

tomo pauk said:

Is the statement in bold drawn out from a credible source or it's just an opinion? P-35 and P-47 are two worlds apart when we talk about basic structure engine.

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I may be wrong, but I'm pretty sure the fuselage of the G50 from cockpit aft was a trussed semi-rectangular light alloy covered structure while that of the G55 was a "modern" oval stressed skin monocoque. If I'm wrong, I'll admit that there may be more underlying similarity than what met my eye. But it doesn't really matter, since we agree the Bf-109 beats it hands down anyway

tomo pauk said:

Is the statement in bold drawn out from a credible source or it's just an opinion? P-35 and P-47 are two worlds apart when we talk about basic structure engine.

Click to expand...

I may be wrong, but I'm pretty sure the fuselage of the G50 from cockpit aft was a trussed semi-rectangular light alloy covered structure while that of the G55 was a "modern" oval stressed skin monocoque. That's a pretty big structural difference. If I'm wrong, I'll admit that there may be more underlying similarity than what met my eye. But it doesn't really matter, since we agree the Bf-109 beats it hands down anyway