P47 Which one as a pure fighter

[FLS]

Slightly off-topic, but why were the jugs replaced by ponies? I have always considered the P47 as a much better aircraft than the pony.

The P-51 had a higher mach number so they didn't compress as soon when diving on bandits at high altitude.

[-ammo-]

I thought it was because as  Hightone said - the P-51 was cheaper to produce.  Also add the range factor which was huge at the time.  The Brits put enormous pressure on the U.S. to increase it's bombing campaign and the U.S. was taking huge losses.  We needed a fighter that could go the distance.  Also, the airframe was designed earlier and the factories had a huge leap forward in tooling and parts.  All that needed to be done was fit the Merlin to it.

[Randy1]

It might have been interesting to compare a fully developed P47M to a P51D had development on the M went beyond the cut to suit, beat to fit, and paint to match stage.

BTW, what was it about a F4U that allowed it to retain energy better than the P47?  They look to have about the same frontal area.

[Saxman]

BTW, what was it about a F4U that allowed it to retain energy better than the P47?  They look to have about the same frontal area.

Because they don't.







The P-47 has that deep belly and tall cowling like the F6F, while the Corsair's fuselage is more or less tubular. There's some claims the gull wing design reduced drag as well, but that's a bit controversial.

[Hajo]

The P-51 had a higher mach number so they didn't compress as soon when diving on bandits at high altitude.

The P47 will out dive a P51 and will out zoom it also.

Reason...weight.  The P47 was a product of 30s technology, the P51 the 40s'.

The P51 had greater range.  Radial engines were great for taking a beating.  No glycol lines to worry about.
Oil hits were less worry to a radial engine also.  Radials however gulped fuel.  Radials were more reliable
but a radial engine added more drag to a fighter.  You'll notice that in general the US Navy used radial engines
chiefly for their reliability and ruggedness. Flying over great expanses of Ocean required  greater reliability,
which the radial engine supplied.

[LilMak]

Although the 51 was cheaper to build, the primary reason it replaced the 47 was range. Republic developed the N to stay competitive and they were originally slated to go to the ETO but victory over Germany sent all the Ns to the pacific. The M was simply a factory hotrod version of the D model and wasn't supposed to be a long production run.  There are written accounts that the ground crews in 47 squadrons were already overboosting earlier model razorbacks making them perform as well or better than the M. Many have argued that the Jug was a better all around fighter than the 51. The 51 was excelent but won out primarily due to its ability to go the distance. I suspect, had the Spitfire been able to fly as far as either the pony or the jug, it would've been the weapon of choice. Grumman test pilots evaluated many of the aircraft in the ETO when they were developing the Bearcat. The two planes they were most impressed with were the 47 and the 190. They liked the 51 but felt it was too fragile as a battle platform. It's also interesting to note tha the 51 got substantially better MPG than the radial equipped birds too so logisitics played a roll as well.

[FLS]

I thought it was because as  Hightone said - the P-51 was cheaper to produce.  Also add the range factor which was huge at the time.  The Brits put enormous pressure on the U.S. to increase it's bombing campaign and the U.S. was taking huge losses.  We needed a fighter that could go the distance.  Also, the airframe was designed earlier and the factories had a huge leap forward in tooling and parts.  All that needed to be done was fit the Merlin to it.

It's likely there were many reasons. The higher speed before compressing is one critical advantage at the altitude the escorts flew at.

[bozon]

It's likely there were many reasons. The higher speed before compressing is one critical advantage at the altitude the escorts flew at.

The 47 was always praised for its diving ability and behavior in the dive. I seriously doubt slightly higher M limit was of any consideration in replacing it.
Range mostly, followed by cost and fuel economy.

Because they don't.

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The P-47 has that deep belly and tall cowling like the F6F, while the Corsair's fuselage is more or less tubular. There's some claims the gull wing design reduced drag as well, but that's a bit controversial.

Frontal area is a poor measure of drag, except that a plane bigger in front tends to be bigger overall.

[FLS]

The 47 was always praised for its diving ability and behavior in the dive. I seriously doubt slightly higher M limit was of any consideration in replacing it.

It's not my opinion. In one of his books Eric Brown said the P-51 was the best bomber escort because of it's higher critical mach. The Air Ministry tested all the fighter aircraft with sufficient range to see which was best.  OF course it's possible the US might not have considered that in their selection.

[Saxman]

Frontal area is a poor measure of drag, except that a plane bigger in front tends to be bigger overall.

Oh, I wasn't really commenting on drag in relation to frontal area, I was mainly pointing out to Randy that the Jug and Hellcat had a pretty noticeably larger frontal area than the Corsair.

[Randy1]

Because they don't.

I see what you are saying.  The belly bulge might well be the issue.

[earl1937]

I see what you are saying.  The belly bulge might well be the issue.

I was told by a Lockheed engineer friend of mine, who said that the shape and length of the prop blades had a lot of influence on drag.  I think the shape of the canopy and wing "wash out" had a lot of influence on drag. The airflow around the fuseledge also should be included in drag elements.

[Randy1]

I was told by a Lockheed engineer friend of mine, who said that the shape and length of the prop blades had a lot of influence on drag.  I think the shape of the canopy and wing "wash out" had a lot of influence on drag. The airflow around the fuseledge also should be included in drag elements.

Probably is a combination of several factors I would guess.

[bozon]

For radials the detailed shape of the cowling had a big impact on drag. This is one of the main reasons that radials tended to have more drag than inlines. The difference is that with inlines you have a smooth fuselage behind the prop that allows the turbulent flow to straighten itself. The cooling drag in inlines comes from radiators that are placed elsewhere in a "clean" airflow and try to get the air to come out of them as smooth as possible. Classic radials (P47/F6F/F4U etc) just swallow all the turbulent air behind the prop into the cowling to cool the engine and let it out in a much less clean way then what you can do with a radiator under the wing/belly. A good radiator design is said to provide a net thrust, compensating for its drag by heating the air (thus cooling the radiator) and accelerating it on the exit - not unlike a jet engine.

Republic with their XP-47J and Hawker with the sea fury designed a very different cowling to their radials which supposedly lowered drag significantly. This allowed the XP-47J to scratch the 500 mph in level flight.

[bangsbox]

Um...D-11 has best skin of all the jugs(dark olive with blue trim and racing strips). it's the only jug I fly and a ride I take often.