Recent content by finite067

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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Thanks a lot for all of your help guys. Your assistance is much appreciated.
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    I thought Nm was a weird way to put it. When I looked at the static thrust info for the engines it gave it me in units of ft*lbs, which I thought would be Nm. If you go on wikipedia and look up the specs for the Pratt and Whitney JT9D's it will tell you. I can't post urls until 15 posts...
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Ok so I found some of the variables: rho=1.1887 kg/m^3 wing area + fuselage cross sectional area = 303.7 m^2 = A C_D=.024 To get C_D I used the calculator from the university of washington. Its the first link when you google "drag coefficient calculator". The variables I used in the...
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Right. 1. But wouldn't the BPR be important here because its important as far as thrust goes? Is there an equation or a concept that I can use to figure out the minimum thrust needed to boost that plane to a certain speed at a certain altitude? I'm sure it would include inlet air density. 2...
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Thanks for the clarification on the subject of the linear variation. I'm still kind of confused on the rest though. Where does the bypass ratio come into play? Also, are aircraft designed to far exceed their design specs? Do manufacturers design the aircraft with huge margins? Could a 767...
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Greg, Thank you for the quick response. The data for the plane in question is: Airspeed Limits: VD = 420 KCAS to 17,854 ft/.91M above 23,000 ft, linear variation between these points. Its for a boeing 767-200. I always thought large airplanes like that could fly at those speeds at high...
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    VD Limit - Explaining its Meaning to a Non-Aerospace Student

    Hello, I'm not an aerospace engineering student but I'm interested in aviation and I had a question. My friend and I got into a debate last night about VD. I believe he said that meant vertical descent. Anyway, he said that if an aircraft has a VD limit = 420 KCAS to 17,000ft/.91M that...
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