"Roy Smith" wrote in message
...
Scott Skylane wrote:
These have been around for quite a while, and they are nothing but an
exercise in compromises.

All airplanes are an exercise in compromises.

First, there is no "yellow arc" allowed on the
airspeed indicator, so redline becomes top of the green.

I know turbines don't have a yellow arc, but I never understood the
logic behind that. Vno (bottom of the yellow arc) is determined by
airframe factors -- IIRC, the ability of the wings to handle the
stresses from vertical gusts. How does taking out pistons and putting
in fan blades change how the airframe reacts to stresses?

It doesn't, turbines are just rated more conservatively. There is nothing
magic about these numbers. Vne is simply 90% of Vd (maximium demonstrated
dive speed), and Vno (Vmo in turbines) is simply 80%. Barry Schiff has a
discussion of V speeds in one of his books.

Mike
MU-2


This restricts you to pretty low true airspeeds at breathable
altitudes. Stay down low, go slow and burn A LOT of gas. Go up
high, go fast, and suck on a nose bag.

But oh man, think of the climb rates you must get!