Tom,
The big difference between the XP-72 and the XP47H was weight.
The "H" was basically a P-47B with the nose severed at the firewall and rebuilt to house the Chrysler V-16. So the aircraft was quite heavy at gross weight over 14,000 lbs.
The XP-72 was built to be light weight, more streamlined, and run two props. Performance testing was done with the single prop as the counter-rotating prop setup was not ready at the time of flight testing.
Added to the mix of testing, the GE turbo-supercharger was not yet fully functional at the time of testing either the 72, 47J, or the 47H as I understand it.
The big difference between the XP-72 and the XP47H was weight.
The "H" was basically a P-47B with the nose severed at the firewall and rebuilt to house the Chrysler V-16. So the aircraft was quite heavy at gross weight over 14,000 lbs.
The XP-72 was built to be light weight, more streamlined, and run two props. Performance testing was done with the single prop as the counter-rotating prop setup was not ready at the time of flight testing.
Added to the mix of testing, the GE turbo-supercharger was not yet fully functional at the time of testing either the 72, 47J, or the 47H as I understand it.