Navalized P-38/39/40: pros cons

pinsog · Jan 19, 2016

GrauGeist said:
If you go back to my post #87 and look at the P-39's diagram, you'll see the subframe assembly that the cockpit attached to.
The cockpit subassembly would have added additional weight to the total airframe weight, but it also tied in with the airframe, adding additional strength.

As it is, removing the car doors and installing a conventional canopy wouldn't help the weight issue much, as the cockpit subassembly would still exist as a component.

Again, referring to the diagram, you can see how the cockpit is designed to be removed in it's entirety in order to perform extended maintenance

Ok. Thank you.

stona · Jan 19, 2016

To get an idea of suitability for carrier operations it would be nice to know some data like take off speeds and runs at various operational weights. At the other end things like landing speed, how much margin above stalling speed did this give? How about the maximum rate of descent (ft/sec) that the undercarriage was designed for. The undercarriages of carrier aircraft were typically designed to deal with a much greater rate of descent than aircraft operated from fields or runways. They were also designed with different oleos etc to prevent the aircraft bouncing down the deck. They were invariably heavier. The angle of the undercarriage is relevant, many land based tail draggers were not designed to make the three point landings generally required for deck landing. In the case of the Seafire the three point attitude exerted a bending force on the main undercarriage which often tore it out of the wing! Others might suffer from similar problems with their landing gear geometry. There may also be aerodynamic problems. These might be irrelevant or even useful when landing on an airfield but potentially lethal when alighting on a carrier.
To navalise an aircraft designed for land based operations to make an acceptable carrier aircraft is often a LOT more difficult than it first appears. What is acceptable? The FAA eventually got the ratio of sorties to deck landing crashes, writing off the aircraft (not all accidents), down to 1:50 for the Seafire III. It took time and improvements in every aspect of operation and training to accomplish this much. It had been much higher on earlier operations. At Salerno the ratio for aircraft written off to all causes except engine failure per sortie was almost 1:10.
1:50 might seem been okay in 1944, but what number is good enough for your navalised P-38/39/40?

Cheers

Steve

pinsog · Jan 19, 2016

stona said:
To get an idea of suitability for carrier operations it would be nice to know some data like take off speeds and runs at various operational weights. At the other end things like landing speed, how much margin above stalling speed did this give? How about the maximum rate of descent (ft/sec) that the undercarriage was designed for. The undercarriages of carrier aircraft were typically designed to deal with a much greater rate of descent than aircraft operated from fields or runways. They were also designed with different oleos etc to prevent the aircraft bouncing down the deck. They were invariably heavier. The angle of the undercarriage is relevant, many land based tail draggers were not designed to make the three point landings generally required for deck landing. In the case of the Seafire the three point attitude exerted a bending force on the main undercarriage which often tore it out of the wing! Others might suffer from similar problems with their landing gear geometry. There may also be aerodynamic problems. These might be irrelevant or even useful when landing on an airfield but potentially lethal when alighting on a carrier.
To navalise an aircraft designed for land based operations to make an acceptable carrier aircraft is often a LOT more difficult than it first appears. What is acceptable? The FAA eventually got the ratio of sorties to deck landing crashes, writing off the aircraft (not all accidents), down to 1:50 for the Seafire III. It took time and improvements in every aspect of operation and training to accomplish this much. It had been much higher on earlier operations. At Salerno the ratio for aircraft written off to all causes except engine failure per sortie was almost 1:10.
1:50 might seem been okay in 1944, but what number is good enough for your navalised P-38/39/40?

Cheers

Steve

All good points Steve. I certainly think the low speed handling would need to be better and a lower stall speed would be nice. I wonder what an extra foot of wingspan would do for both? Anyway, the early war US Carriers could certainly use a plane that was faster and better climbing than the F4F4 Wildcat. Wonder if P39's with their extra performance could have climbed fast enough to break up the dive bomber attack on the Yorktown at Midway? They would certainly be better at shooting down Kate torpedo bombers at wave top height, between their high speed at sea level and a 37mm cannon (provided the ejector chute was modified making the 37mm reliable)

Navalized P-38/39/40: pros cons

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