Thanks for the response. I'm not really interested in flying the transports..I was just conversing with a pilot friend, and he seemed to think that the IAS would be outrageously low....like 100kts, which to me seems insane. I mean, if you were getting 100kts IAS at FL360, wouldn't the plane be really close to stalling? I figured the IAS would be somewhere around 230ish, give or take.
As you climb the air gets thinner. This thinner air means there is less for the wings to grab onto and less air to ram into the pitot tube. The drag of the air also decreases. This decrease in drag is what makes you so efficient.
Now let's get back to indicated airspeed. Your airplane is going to stall at the same indicated airspeed for the given weight. The airplane will stall at different true airspeeds. True airspeed really does not mean much. If you did not have any winds aloft to consider--true airspeed equals your ground speed. Indicated airspeed does not equal your ground speed.
100 knots? I doubt it.. Some quick numbers
FL350, 400 KTAS, -50C == 220 KIAS
FL400, 400 KTAS, -60C == 200 KIAS
FL450, 400 KTAS, -70C == 180 KIAS
FL500, 400 KTAS, -80C == 160 KIAS
That's all basically pretty linear looking which surprises me. So my math could be wrong but it's probably about right. The higher you climb and the closer you will get to stall speed. Can you say Pinnacle Flight 3701?
It's interesting how many general aviation pilots really do not understand true airspeed. They also don't understand how to best take advantage of their piston engine. This brings up an entirely different subject albeit still interesting.
As you climb in a piston engine your maximum power decreases. The drag on the airplane decreases as well. The nice thing is since the drag has decreased you no longer need as much power to develop the same true airspeed. This equates to lower fuel burns as well. The sweet spot for a normal aspired piston engine is generally between 7,000 to 10,000 ft. You can achieve almost the same KTAS as you can at sea level while being WAY more efficient which means less engine stress and a lot of fuel saved.