According to Warren Bode in his definitive book on the P-38, the bob weights
in the center of the elevator were mandated by the Army after one of the
YP-38's shed its tail in a dive. Further dive tests seemed to indicate that
the problem was tail flutter at certain speeds. The bob weights were added
but did not solve the problem. Wind tunnel tests eventually traced the
"flutter" problem to buffeting from turbulence off the joint between the
wing and the center fuselage pod. After a fillet was added to soften this
joint, the "flutter" problem disappeared, but the Army would not let Johnson
remove the bob weights. He hated them (the elevator was already
counterbalanced by concealed weights in the tail cones) and felt that their
only contribution was to kill a few pilots who hit them in bailouts. The
"compressability tuck" problem was investigated at the same time, but was
only solved by means of the dive brakes that were added to the P-38J-25-LO
and subsequent models. As it turned out, the compressability problem could
not occur in any P-38's if dives were initiated below 25,000 feet. Since
most P-38 operations during the war were below that altitude, few pilots
encountered the problem in combat.
--
Bob (Chief Pilot, White Knuckle Airways)

"Morgans" wrote in message
...

"Big John" wrote in message

The P-38 had high speed dive problems. After a number crashed they
went back and retrofitted them with 'dive' brakes (narrow strips on
top of wing that could be raised to increase drag). These slowed the
bird down enough it could be pulled out

Wasn't part of that fix also a mass balancer on the elevator, that was a
blob raised up on an arm above the elevator?
--

Jim in NC


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