"Ed Rasimus" wrote in message
...
On Fri, 9 Jan 2004 09:50:55 -0800, "Tarver Engineering"
wrote:


I think we can pretty well know the iris on the J-75 was taking out 1% of
the F-105s.

Are you referring to the turbine Christmas tree? Failures of the
Christmas tree which held the three stages of turbine blades caused a
number of unexplained losses. I mention the bailout of Joe Vojir on
takeoff at Korat as well as the loss of Buzz Bullock and Dain Milliman
in takeoff accidents caused by turbine failure in When Thunder Rolled.

I am refering to the AB nozzle, the iris at the back. It was a high failure
rate item, if stuck open offered the operator power in AB settings only, if
stuck in between, only lead sled power settings were available.

The AB nozzle (iris) didn't cause any accidents that I know about.
And, the nozzle is not synonymous with the speed brake petals or
pizzas (which were removed in '65).

The AB nozzle was a sticky part of the J-75.

When Ed posted here that the F-105's brakes could not hold the
airplane in AB, I could see that iris stuck open/closed/half way between.

No afterburner equipped aircraft that I know about can be held by
wheel brakes in AB. Carrier aircraft get into AB for launch by
employing a "hold back". The F-4, for example, couldn't be held in
military power by the wheel brakes. Engines were checked at 100% one
at a time. Takeoffs were done with a runup to 85% prior to brake
release, then to mil and finally to AB.

I don't believe the F-4 had the nozzle problems associated with the J-75 AB.