Morgans wrote:

"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

More likely the mass balance was used to raise the flutter speed of the
elevator. Get it up above the airplane's speed range.

Also, while on the subject of P-38 lore...

I thought the dive brakes retro on the P-38 was on the bottom of the
wing?

Part of the problem was that even though the airplane was traveling at
less than transonic speed, there were places that the "air" was getting
supersonic and creating shock waves.

(I put that in quotes, because it's really the airplane that's moving,
not the air. The air just gets out of the way - rapidly. Can't blame
it.)

Then, as speed builds, the shock waves move aft?

The Bell X-1 had some problems with the shock waves moving aft on the
elevator. Moved right back to the elevator hinge line and elevator
control was rather - uhm - nonexistent?

The airplane also had a variable incidence stabilizer for elevator trim.
Chuck tried flying the airplane with the trim switch and the "all
flying"
tail, or stabilator was born.

If this is happening on the wing, as the pressure point moves aft the
nose tucks down very nicely!

As pressure increases due to decreasing altitude, the airplane might
slow
enough to return to normal subsonic conditions, and regain control.

But you'd best be hauling that nose up now!


Let's say you recover control at 25,000 feet?
You are pointed straight down at 500 mph.

You are going a little faster than 8 miles a minute,

and you are slightly more than 4 miles up...

I think it takes about 1.6 seconds from initiation
for the seat to clear the airframe...


Richard