Originally posted by GRUNHERZ
This is such an amazingly outdated design for a 1945 US prototype.
The design was ordered in 1943 specifically for tank busting and anti-shipping. It's first flight was in 1944.
While it appears superficially to be a dated design, it really wasn't at all. Actually, it was remarkably innovative in many respects.
Engine selection: Choosing a pair of the big R-3350 engines meant that the aircraft would have tremendous power, 4,600 hp with restricted boost (2,600 rpm @ 45 in/hg), 5,200 hp at full factory rated power (2,800 rpm @ 48 in/hg). Documents describing the initial factory testing of the XA-38 were most recently located in the Walter H. and Olive Ann Beech Collection, which is currently in the custody of the Wichita State University library. Additional AAF test data is stored on microfilm in the National Archives.
Standard gross weight, less external stores was just over 31,000 pounds. This provided a wing loading on par with most late-war fighters. The A-38 employed clever slotted flaps that effectively increased wing area by 20% when fully deployed.
The aircraft was of modular construction, consisting of four major sub-assemblies, plus the weapons module.
Another unique feature allowed for the entire nose mounted weapons package to be removed and replaced in about two hours. The entire nose module of the aircraft was unbolted and could be replaced with various gun packages, including six 20mm cannon or eight .50 caliber Brownings. This would have allowed the aircraft to be tailored for specific missions to a degree not previously seen in the USAAF.
Performance was considerably better than that of the A-26. I have never seen a climb chart for the XA-38, but I have seen pilot comments from the Eglin tests. One pilot stated that it took just over two minutes to reach 5,000 feet from brake release. That should put the XA-38 in the area of 3,000 fpm, again restricting MAP to 45".
A P-47D was used as a chase plane during some of the flight testing. Pilots reported that the XA-38 proved a better climber and was much faster than the Jug below 10,000 feet. A glimpse of this can be found on the USAF Museum site, where they state, "Every means possible was employed to decrease drag, including flush riveting of all exposed skin surfaces. A striking demonstration of the resultant speed was furnished the Army when it assigned one of its fastest fighters to pace the XA-38 for speed calibration tests and found the Beechcraft outdistancing the fighter. "
Also stated is the following: "The Beechcraft Model 28 combined the size of a medium bomber with the speed of the fastest propeller driven fighters of the day. It was highly maneuverable and could take off and land in an area considerably smaller than needed by other airplanes of a comparable size." Pilots at Eglin reported that the XA-38 "turned much tighter circles than the P-38 or P-47."
Overall, the AAF was extremely pleased with the XA-38. However, in selecting the R-3350 engines, Beech found itself with a major problem of availability. Virtually all R-3350 production capacity was earmarked for B-29 production, which had a far greater priority than another medium attack plane. Beech considered a redesign to switch over to the P&W R-2800 C series engine, but the AAF would not allocate the addition funds to finance the change simply because the bulk of production capacity for these engines was assigned to P-47N and F4U-4 production. Moreover, it was recognized that this redesign would push back development at least 9 months, and probably a full year. Both XA-38 prototypes lived out their short lives as test mules. However, they were very highly regarded by the test pilots who flew them.
If we look at the XA-38 within the context of its intended mission, we would see that the XA-38's role was similar to that of the HS 129. Indeed, the XA-38 was to the HS 129 what the P-47M was to the Seversky P-35.
My regards,
Widewing
