Originally posted by BigCrate
Widewing where did you get that chart??? My lockheed doesn't back up that chart? Also it does sort of.. I sent this lockheed stuff to Badz ohh about 3 and half years he used on the p38 dive flap post..... it was a book strait from lockheed.. and it explained so much about the p-38 and its compression problem. This graph it from this book. and is the only one anyone has scanned. i would scan the entire thing if I could. anyways it showed maimum indicated speed possible from 40,000ft on down and around 28,000ft it 38 could reach 600mph.and lower alts the 38 could reach 550mph with ease. And it also shows indicated speed for maximum dive tendency. From 40,000ft on down and could get up to 550mph.. But at lower he could dive with releative safety to 525mph at lower alts. The 38 in AH really can't much these numbers. because the 38s dive flaps don't work the way they should and and the 38... But the 38 can't reach these speed at lower alts but it is at higher alts is where the 38 dive performance is porked
This graph also show then bufet starts at 1g of acceleration that is 475mph at 4,000ft And the speed decreases with alt.
CW
Let's deal with these issues for you one at a time.
The graph is a copy of that available in the familiarization manual issued to pilots reporting for training at a P-38 RTU (training unit). It incorporates flight test data compiled by Lockheed test pilot Milo Burcham, and is the Gospel. You can see an actual photo of the chart on page 215 of my friend Warren Bodie's book on the P-38, available from Amazon.com in reprint (now a softcover).
Any pilot claiming to have reached 600 mph in a P-38, and living to tell about is either mistaking, or the luckiest man on earth. At speeds exceeding Mach 0.75 buffeting was severe. At Mach 0.85, (assuming that was even possible, which I doubt) it would likely be fatal to the aircraft and pilot. Moreover, simply reaching 550 mph was beyond the safe upper limit, even at sea level. 525 mph was right at critical Mach at sea level, with the onset of buffeting having already begun.
I have no issues with the AH modeling of the P-38L, other than rate of climb which I believe to be too low. Granted, the dive brakes don't work correctly. If they did, the P-38 would recover from a dive hands-off, with a steady 3G load. These dive brakes did three things. First, they induced drag, limiting both acceleration and velocity. Secondly, they induced a pitch up condition. Lastly, they shifted the center of lift forward along the chord of the wing. These last two combined to prevent the dreaded "dive tuck" that usually proved fatal to the plane and pilot. If HTC fixes the dive flaps, you will be have to deliberately hold the nose down in a high speed dive or it will simply pull out all on its own (assuming neutral trim).
The chart you are referring to defines the speed/G loading that induces buffet. This is Figure 25, located on page 30 of the P-38L pilot's manual. Figure 25A shows the same data as my chart, which is for normal gravity (1 G) loading.
Get Warren's book. It's the best published source for obscure P-38 history and data.
My regards,
Widewing
