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![]() "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! |
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On Wed, 24 Dec 2003 23:18:41 GMT, "Mike Rapoport"
wrote: "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 According to Bell in "Those Incompairable Bonanzas" Vne is 80% of the tested dive speed in the Bo, where it is 90% in almost all other aircraft. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair?) www.rogerhalstead.com 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! |
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![]() "Roger Halstead" wrote in message ... On Wed, 24 Dec 2003 23:18:41 GMT, "Mike Rapoport" wrote: "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 According to Bell in "Those Incompairable Bonanzas" Vne is 80% of the tested dive speed in the Bo, where it is 90% in almost all other aircraft. 90% of Vd is the maximium that Vne can be. Some airplanes have a Vne lower than 90% of Vd for various reasons. In the MU-2 Vd is 345kts and Vmo is only 250kts or 72%. It had something to due with the CAR 3 standard that it was certified under and the fact that the early MU-2s couldn't do 250kts indicated in level flight anyway. Even though the later models have almost twice the power as the originals and will easily reach 250kts indicated as high as 16,000', the 250kts Vmo was left unchanged. Mike MU-2 Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair?) www.rogerhalstead.com 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! |
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