Corsair and Hellcat in Europe

[RCAFson]

Agreed. But this is where your hypothetical exercise needs to begin.

Otherwise, as I wrote above; in a sea of Wildcats, Hellcats and soon Corsairs, they'll be no Merlin naval fighter for the USN.

The USN didn't begin to operate Hellcats and Corsairs in any number till mid 1943, that's very long time from Nimitz's request of June 1942.

Nimitz's telegram seems to be going a long way to say a couple of things:

1. We need Army planes for the land based Marines so we can put all available Wildcats on carriers. Okay. Not that there were any Army planes available in June '42, but not impossible depending on the number of land based Marine squadrons.
2. We need to lighten the Wildcats and increase ammunition capacity. Okay, that could have been done immediately aboard the carriers. Remove two of the six guns and put more ammunition in the Wildcat's four remaining ammo boxes in the wings.

Converting P-40s for carrier use may have been an impossible job. Folding wings, tail hook, big weight reduction (P-40F weighed 8500#), strengthened landing gear and who knows what else.

Corsair didn't get into combat until Feb '43 and that was for Marine/land use. Hellcat didn't get into combat until fall of '43. Probably could have had the Corsair ready for carrier use before a reworked P-40.

There was no shortage of F4F-4s in the Pacific, especially given the reduced number of carriers available to the USN.

There were field mods to reduce guns to four and increase ammo, but the net result was that TO weight remained the same and there was no increase in performance.

 

[XBe02Drvr]

The USN didn't begin to operate Hellcats and Corsairs in any number till mid 1943, that's very long time from Nimitz's request of June 1942.

A year. Less time than it would take to get a V12 powered fighter modified and into combat service.

 

[Shortround6]

The U.S. Navy got P-40F 41-13701 on June 6th 1942 to Anacostia Naval AIr Station for comparative tests against the F4F-4, results were mixed.

The Navy found that the P-40F was superior in speed and climb below 20,000ft with the F4F-4 superior above 20,000ft. At 24,000ft the F4F-4s advantage in speed and climb was marked but the P-40 could easily dive away. (no numbers are given in the acount)
The P-40F had the 52 gallon drop tank (otherwise the two planes were within a few gallons of each other) and while the there were under wing tanks for th ef4F-4 under test they were not operational at this time.
Visibility from cockpit was markedly better in the F4F-4. The P-40F had a better gunsight but the Navy thought the F4F-4 was a much better gun platform, due to the poor visibility over the nose of the P-40F, high rudder forces, tendency to abrupt high speed stalls. All these made close-range, full deflection shooting very difficult.
The Navy thought the P-40F had a quieter cockpit with better temperature control and ventilation but thought the cockpit was cramped compared to the F4F-4. The P-40F had a much higher rate of roll.
Wither CinCPAC was even aware of this test (being thousands of miles away) is questionable.

No mention is made of any carrier suitability tests done with this aircraft.

 

[P-39 Expert]

Here's a comparison of the F4F-4 and a P-39K (early P-39 with 8.8 supercharger). The P-40F performance was almost exactly the same as the early (8.8) P-39(D/F/K/L).

 

[gjs238]

At NATTC they had an FJ Fury (the latest swept wing version) that had more patches, straps, and braces to deal with fatigue cracking than you could point a stick at. It was a thousand pounds overweight, and kept as an example to impress AMS (Aviation Maintenance, Structural) trainees of the seriousness of their trade.
Cheers,
Wes

Do they still make such repairs today?
I frequently hear in the news about airframe fatigue as a reason for aircraft retirement.

 

[gjs238]

Let's not forget that all-metal stressed skin, monocoque, cantilever monoplane technology was a relatively young art at the time. The highly detailed computer based stress analysis we have today just wasn't as robust in the day of the slide rule, so the temptation to add a little extra "beef" for "safety's sake" tended to settle in. Some designers (Horikoshi and Heinneman come to mind) managed to resist this temptation, but so many did not. And this "overbuilding" did in fact often enhance survivability under combat damage conditions. The "Grumman Iron Works" EARNED their title!
Cheers,
Wes

This seems to be how the P51-H came about.
Field use revealed that the earlier versions could indeed be lightened.

 

[XBe02Drvr]

This seems to be how the P51-H came about.
Field use revealed that the earlier versions could indeed be lightened.

Experience counts.

 

[XBe02Drvr]

Do they still make such repairs today?
I frequently hear in the news about airframe fatigue as a reason for aircraft retirement.

Fatigue will always be with us, especially in high-cycle aero-elastic structures. At this time, we have 70 years experience with flexible swept wing airplanes, and we still don't know it all. The only way we get 50K+ hours and cycles out of them is by constant inspection and repair. Cracks WILL form, and cracks WILL propagate as the cycle count goes up, no matter how badly we curse and complain. Repair techniques have become more sophisticated over the decades, but they still owe homage to patches and straps and braces. Composite materials have added a few more arrows to the quiver. And I'm sure there's new stuff out there I haven't heard of yet.
Cheers,
Wes

 

[Glider]

This seems to be how the P51-H came about.
Field use revealed that the earlier versions could indeed be lightened.

I think you will find that the P51H came about because it was designed using UK standards for airframe design not American. Supermarine were consulted in the early days of the design regarding the approach used by the UK.

 

[XBe02Drvr]

I think you will find that the P51H came about because it was designed using UK standards for airframe design not American. Supermarine were consulted in the early days of the design regarding the approach used by the UK.

And once again the mutha country asserts her mastery.

 

[BiffF15]

Fatigue will always be with us, especially in high-cycle aero-elastic structures. At this time, we have 70 years experience with flexible swept wing airplanes, and we still don't know it all. The only way we get 50K+ hours and cycles out of them is by constant inspection and repair. Cracks WILL form, and cracks WILL propagate as the cycle count goes up, no matter how badly we curse and complain. Repair techniques have become more sophisticated over the decades, but they still owe homage to patches and straps and braces. Composite materials have added a few more arrows to the quiver. And I'm sure there's new stuff out there I haven't heard of yet.
Cheers,
Wes

I've flown Eagles with wing straps, patches, cracks and stop drilled cracks. Very flexible plane I guess! The interesting thing is how long the planes stay around given how hard we whale on them. I flew 1975-76 F15A models into the 2007-2009 timeframe.

Cheers,
Biff

 

[Glider]

And once again the mutha country asserts her mastery.

Oh yea of little faith. I suggest you have a look at the attached

P-51 Mustang Variants - P-51H - MustangsMustangs.com

 

[XBe02Drvr]

I flew 1975-76 F15A models into the 2007-2009 timeframe.

How about Tomcats of that vintage who were still bashing the boat when their wings were clipped in 2006? Patches on top of patches.

 

[XBe02Drvr]

The interesting thing is how long the planes stay around given how hard we whale on them.

And didn't a few of them come unglued midair?

 

[BiffF15]

How about Tomcats of that vintage who were still bashing the boat when their wings were clipped in 2006? Patches on top of patches.

Yeah, they were just kept around as training aids for the rest of us.

In reality they flew with a lot of restrictions, at least when I fought them. Not sure on their utilization rates or traps to hours flown (wear and tear markers). It's a cool plane to look at but was designed to shoot down bombers over water and wasn't optimized for fighter versus fighter operations. It was cool fighting them after watching Top Gun.

Cheers,
Biff

 

[BiffF15]

And didn't a few of them come unglued midair?

Several have, mostly from the pilot pulling the wings off. The St Louis ANG crash was one of the top five over G'd F15s in the USAF, AND there was a structural defect in its longeron (fore aft spar if you will). Don't forget the plane initially had a 7.3 g limit until the F16 came out. Then MacAir invented a overload warning system (OWS) to allow pulls of up to 9 G's if they were symmetric. Nothing was beefed up structurally to go from 7.3 to 9. Old guys with Slide rules Rule! If you get a chance to look down a DC-8 fuselage you will notice the skin is without wrinkles regardless of its age. Not so on Boeing or Airbus. MacD made aerial tanks.

WGASF (Worlds Greatest Air Superiority Fighter).

Cheers,
Biff

 

[XBe02Drvr]

It's a cool plane to look at but was designed to shoot down bombers over water and wasn't optimized for fighter versus fighter operations.

Interesting. That's not the hype we were given when it was being developed. I'm sure you've seen the promotional film "No Points For Second Place", n'est-ce pas? All about ACM and furballs. MiG killer par excellence. Interesting to hear a different perspective. Of course high speed standoff missiles launched from supersonic bombers were always a concern, and I believe, the impetus for the Phoenix missile.
Cheers,
Wes

 

[Zipper730]

Don't forget the plane initially had a 7.3 g limit until the F16 came out. Then MacAir invented a overload warning system (OWS) to allow pulls of up to 9 G's if they were symmetric. Nothing was beefed up structurally to go from 7.3 to 9. Old guys with Slide rules Rule!

Since they couldn't compute exact strength, they usually erred on the side of caution. That's why a modern plane rated to a given amount seems flimsy to an older design. It actually is, in a way, since people can better compute what the exact limit is, they can build right onto that limit.

If you really wanted to evaluate strength, you'd want to evaluate an old plane's strength with modern technology; then use the figures you got out of that as a baseline figure, and you'd be building as tough as the past.

If you get a chance to look down a DC-8 fuselage you will notice the skin is without wrinkles regardless of its age. Not so on Boeing or Airbus. MacD made aerial tanks.

That had to also do with older-fashioned ideas about how a design should last as long as the customer wants it to. If you want to keep it a long time, we'll keep repairing it. Boeing, from what it appeared, seemed to subscribe less to the idea: The 707 for example was expected to last 40,000 hours. While the plane could probably be repaired and maintained past that point, there was the presumption that people would probably just buy the newer model.

This idea, when carried to conclusion, results in what's called planned obsolescence: You design a product to fail after a certain amount of time, so people would have to buy a newer model. I'm not a big fan of this practice.

 

[XBe02Drvr]

there was a structural defect in its longeron (fore aft spar if you will).

Not to be a nitpicker, but in the airframe terminology I was taught, the main fuselage longitudinal structural member (fore - aft spar if you will) is the keel. Longerons (always in the plural) are smaller distributed-stress longitudinal members in the fuselage. Since the advent of aluminum monocoque construction, keels have become less common (except in boat bashing birds), since longerons are more readily integrated into monocoque construction.
Cheers,
Wes

 

[BiffF15]

Not to be a nitpicker, but in the airframe terminology I was taught, the main fuselage longitudinal structural member (fore - aft spar if you will) is the keel. Longerons (always in the plural) are smaller distributed-stress longitudinal members in the fuselage. Since the advent of aluminum monocoque construction, keels have become less common (except in boat bashing birds), since longerons are more readily integrated into monocoque construction.
Cheers,
Wes

Roger, copy! It was a longeron in aircraft specific speak. When the canopy is raised and the pilots arm is resting on the rail, that is the top of the longeron in the Eagle (can't speak to other aircraft and am not trying to be sarcastic/ humorous). It's a C shaped beam, or half an I beam that had several manufacturers or methods in which some were not to spec.

Cheers,

Biff