On Tue, 23 Sep 2014 08:34:58 -0400, Ed Huntress
wrote:

On Tue, 23 Sep 2014 18:45:05 +0700, John B. Slocomb
wrote:

On Mon, 22 Sep 2014 22:21:30 -0400, Ed Huntress
wrote:

On Tue, 23 Sep 2014 08:19:55 +0700, John B. Slocomb
wrote:

On Sun, 21 Sep 2014 21:57:03 -0400, "Jim Wilkins"
wrote:

"John B. Slocomb" wrote in message
om...
On Sun, 21 Sep 2014 11:09:18 -0400, "Jim Wilkins"
wrote:


much snipped

The F-111 and its variants, including the FB-111, used titanium where
they had to, where skin friction at high speeds generated too much
heat for aluminum, and then they used aluminum where they could get
away with it. Those aircraft also employed steel in parts of the
airframe.

You can't use aluminum above Mach 2, roughly. The limit is around 300
deg. F, which was the result of skin friction at high speeds. It loses
too much strength above that temperature. That's what limited the
Concorde's speed, too; it was aluminum, for cost. Above that you need
titanium or steel. The Russions, despite their considerable expertise
in metallurgy and a good supply of titanium, couldn't weld it. So the
Mig 25 (Foxbat) was skinned and framed in steel.

While I was at Edwards with the FB-111 I worked in the "Base Shops"
for a while and some guys came in with a nose gear, obviously from a
small airplane. It had no data plates or other obvious markings on it
and the question was how to get it apart. I got called in because I
was Air Force and the rest of the shop was civilians, so I got to look
it over pretty closely.

It was a complete nose gear strut with the trunions on the top and the
axle on the bottom. Obviously an Oleo strut, there was a high pressure
air valve in the top. But no way to disassemble it. It appeared that
it was somehow assembled and then welded together and no way to take
it apart.

I asked the guys "what kind of airplane did this come off?" and got no
answer. Based on the timing I suspect that it was the nose gear from
the MIG that was flown to Taiwan and then sort of disappeared.

I never worked on small airplanes and I don't know how much nose gear
problem they have (the big ones don't have much) and the strange nose
gear was pretty light. Maybe a steel tubing, welded together, change
the whole thing, nose gear makes sense. A lot of the things the
Russians did that were condemned as "crude" actually made very good
sense.

They made a lot of things for reliability and easy maintenance, and
their military equipment was often selected by third-world countries
for that very reason. They also made a lot of junk for non-military
applications.

The Soviets had especially good metallurgists.

I worked at a steel plant in E. Java that was started by the Russians,
who left abruptly when the local communists attempted a coup, leaving
all the heavy equipment behind. It was noticeable that most of the
equipment was not made of "exotic" alloys (crane booms looking like
U.S. 50 ton and rated for 30 tons) and every engine had at least two
starting methods, some had three.

We reckoned that it might get cold in Russia :-)
--
Cheers,

John B.