About the Spitfire IX at very high speeds

[Jochen]

The reason for the Spitfire’s outstandingly better high Mach number behaviour is due to the fact that it had a thickness to chord ratio of 13 percent, compared to the 16 percent of the Mustang, which also had a more draggy cooling system and a thicker tailplane.

roadkille!!! Spitfirer had far more draggier radiator housings that Mustang had!

Mustang used expansion of air in radiator to create bit of thrust while in Spitfire air just went trough causing drag.

[Seeker]

I stand corrected, Mach 0,97 is obviously too high, sorry to have been  misleading .

The rest stands, unless any one has any data otherwise?

[Dweeb]

Originally posted by Seeker:

The rest stands, unless any one has any data otherwise?

Yep, the Spitfire clearly had the best maximum dive speed in the war. That seems to be reflected in the game.

Dweeb

[Dweeb]

Originally posted by Jochen:


roadkille!!! Spitfirer had far more draggier radiator housings that Mustang had!

Can you prove it?

Dweeb

[Badboy]

Originally posted by Seeker:
The Spit IX is the fastest diving piston engined fighter of WWII.

Correct!

 

You'll also blow the prop off, just like they did at Boscombe down.

Nope, the Spitfire was flown to Mach 0.9 on several occasions and by more than one pilot, the prop accident was a one off caused by a faulty thrust bearing, that transfers the pull of the airscrew to the engine through ball bearings, it never happened before or after.

Badboy

[bolillo_loco]

hey somebody correct me if I am wrong, but after the mk XIV didn't the spit get a laminar flow wing. I mean spit mk XX series were a much different a/c than a spit mkII thru MkIX series which were basically the same except for aileron and engine changes. Just look at the max weights for the Mk XX series and higher, my book says take off weight was around 9,000+ lbs and max t/o was over 10,000lbs, but feel free to correct me.

also at those hi mach numbers, would not the prop be the limiting factor? the test in which the 47 dove at speeds beyond mach .8, it had a special propeller and I was under the impression that with the standard prop no matter how far you dove a 47 it would never exceed mach .85 just due to prop drag.

[CJ]

Look in any journal on low-drag cooling systems in liquid cooled aircraft,and they'll use the P-51 as the example on how to make it low drag.  The spitfire on the other hand is known for a fairly primitive duct design for the radiator.  I'm not knocking the Spitfire.  It would have been even more spactacular with a low drag cooling system, but its ducting wasn't very impressive compared to the amount of research done for the P-51's.

[Nashwan]

What I'd allways understood about the P-51 radiator installation is that it was high drag, but used the Meredith effect to actually produce almost enough thrust as it did drag.
If that's true, at very high speeds the thrust it produced wouldn't have gone up much, and may have gone down, but the drag it created would be much higher.

The Spit 21 and later marks had a redesigned wing, but I don't think it was laminar flow.
The Spitefull, which was based on the Spitfire and intended to be it's successor, had a laminar flow wing. Around 20 prototypes were made, but production was abandoned before the end of the war in favour of jets.

[Widewing]

Originally posted by Nashwan:
What I'd allways understood about the P-51 radiator installation is that it was high drag, but used the Meredith effect to actually produce almost enough thrust as it did drag.
If that's true, at very high speeds the thrust it produced wouldn't have gone up much, and may have gone down, but the drag it created would be much higher.

My question is this: If the P-51 has a high drag radiator design, and does not producing as much thrust as drag, why is a P-51B more than 30 mph faster than the Mk.IX using, essentially, the same powerplant and still weighing 2,000 lbs more empty than the Spit?

My regards,

Widewing

[Angus]

What I know from history:
109's escaping from Spitfires with a power dive would someties break wings off or compress completely or crash while the Spitfire would recover and pull up.
The Spitfire would not be the perfect choice for a dive, because for a good while it would lag behind the others, - however it could take a lot of speed.
The P51 had a good elevator control as well. A WW2 Pilot flying both Spitfires and Mustangs told me that the P51 would get faster in a dive. That was the P51C vs. the Spit 9.
The same pilot managed to get a fully armed Spitfire 9 up to 49000 feet. He said that the Spitfire topped the P51 in really high altitudes, if there was a difference. I.e. if in anyones favour, the Spitfire was the winner.
Wonder which (if any)of the ww2 aircraft had thinner wings than the Spitfire....  
So, you all see, the Spitfire was just the coolest...more ahead of its time than anything. Long live the Spit!!!!!!!!!  

[wells]

From the August 1993 issue of Aeroplane Monthly.

 

[Nashwan]

My question is this: If the P-51 has a high drag radiator design, and does not producing as much thrust as drag, why is a P-51B more than 30 mph faster than the Mk.IX using, essentially, the same powerplant and still weighing 2,000 lbs more empty than the Spit?

Because the Spit produced very little positive thrust from its radiators, the Mustang a lot.
If the Spitfire produced 200lbs of drag and 50lbs of thrust, and the Mustang produced 300lbs of drag and 250lbs of thrust, which plane would go faster?
And if speed increased greatly, and drag doubled or trebled, whilst thrust went up hardly at all, which would go faster then?

[bolillo_loco]

thanks for the chart wells!, now my question would be, did the spit Mk XIX had a very different wing than the spit mk IX and Mk IX not?

how much weight did the Mk XIX gain over the earlier Mk XIV and IX models? I always thought that one other reason why the spit mk IX did not compress was due to the fact that it was very light and did not pick up speed rapidly in a dive due to this reason. thanks again!

[ 01-11-2002: Message edited by: bolillo_loco ]

[Karnak]

Spit XIX has the same wing, for all intents and purposes, as the Spit IX.  The new wing was introduced in the Spit F.21.  Minor differences are in the alirons, they don't extend as far out as on the F.IX, and the radiators, the Griffon 65 engine requiring greater cooling and thus the ratiators being larger and producing more drag.  Of course as the PR.XIX is unarmed there are no cannon or machine gun ports/blisters.

The Spitfire XIX was a PR Spit, esentially it was the PR version of the Spit XIV.  The take off weight of the PR.XIX was 8,575lbs.

[bolillo_loco]

No kiddin karnak. Thanks for the information. so then could a spit IX achieve this performance also?