High-Drag Areas on the Supermarine Spitfire

[wuzak]

From that POV a Mustang style belly scoop sounds like a good idea, with the inlet in line with the high pressure under the wing and the outlet in the lower pressure zone well behind the wing?

The Mustang air scoop is in the freestream air, with a gap to the fuselage to keep away from the boundary layer.

 

[z42]

Like a chin radiator?

Nah. I think a chin radiator doesn't have the space for the long diffuser with a suitably low angle duct providing smooth low velocity high pressure flow at the radiator face. So I was thinking of having a P-51 style flatt(-ish) scoop under the engine, and then the radiator core itself behind the engine. But, the need to have space for the landing gear in the nacelle behind the (inner) engines probably kills that idea.

 

[z42]

The Mustang air scoop is in the freestream air, with a gap to the fuselage to keep away from the boundary layer.

That is true, however the pressure field from the wing and airframe extends far beyond the boundary layer.

 

[elbmc1969]

Nah. I think a chin radiator doesn't have the space for the long diffuser with a suitably low angle duct providing smooth low velocity high pressure flow at the radiator face. So I was thinking of having a P-51 style flatt(-ish) scoop under the engine, and then the radiator core itself behind the engine. But, the need to have space for the landing gear in the nacelle behind the (inner) engines probably kills that idea.

It absolutely can. It's a question of how you set it up.

 

[Deleted member 68059]

It absolutely can. It's a question of how you set it up.

I`ve never seen one that did for the main water radiator, same reason the Spitfire wing radiator installation falls a long way short of ideal, not enough space caused by proximity to wheel-wells/wheel doors. Works ok for an oil cooler as its such a small matrix you can fit in a decent contraction/expansion ratio duct.

 

[tomo pauk]

I`ve never seen one that did for the main water radiator, same reason the Spitfire wing radiator installation falls a long way short of ideal, not enough space caused by proximity to wheel-wells/wheel doors. Works ok for an oil cooler as its such a small matrix you can fit in a decent contraction/expansion ratio duct.

View attachment 704860

Both of the coolers are under the engine there.

 

[elbmc1969]

I`ve never seen one that did for the main water radiator, same reason the Spitfire wing radiator installation falls a long way short of ideal, not enough space caused by proximity to wheel-wells/wheel doors. Works ok for an oil cooler as its such a small matrix you can fit in a decent contraction/expansion ratio duct.

The Swiss D.3801 variant of the Morane-Saulnier 406 featured quite a long duct. I believe that it could have been longer in a dedicated design (extending the duct further forward, as a start). Not that this radiator was good or achieved the effects in question, on that it shows what's possible.

 

[spicmart]

How would you rate the Spiteful overall aerodynamically in comparison to the P-51H? Top speeds were comparable but which fighter needed more power to achieve them?

Would a Spitfire with a P-51H scoop have been the almost perfect interceptor/dogfighter, combining the handling qualities of a Spit while not having the vicious characteristics of the Spiteful?

 

[Macandy]

The Spitfire was a very draggy plane.
Surface finish was poor, radiators were terrible, canopy was also a notable point.

Despite being significantly heavier, with the same engine, the P-51 was some 30mph faster.

The Spitfire was a 30's design that had reached the end of the line with the MkIX

 

[AndyRicco]

I kindly asked the folks over at Aircraft Restoration Company at Duxford, and they said the PL983 (MK XI) is about 20mph faster than a typical MK IX across the speedrange at same power setting.
This difference is lack of external equipment only. PR windscreen, no cannon or ejector ports and retractable rear wheel.

Max speed difference is problably closer to 30mph faster.