Sec 320 in FDE .AIR file

[Guest DC-8 Jet Trader]

Hi all.My first post here. Together with some other people we are making a new DC-8 panel and dynamics. The only problem we are facing now is that we can't continue on the eir file since we don't know what that Sec 320 is doing in some calculations ...An example= Cdf = Cd_df * Max_defl(rad)Sec 320.What does that Sec 320 means. Can it be the Secans (1/cos) or is this something else? Any help will be much appreciatedRegardsJessDC-8 Projectwww.V1-rotate.org

[WarpD 824]

Cdf = Cd_df * Max_Def(rad) where Max_Def(rad) is located in the 320 record.

[Guest DC-8 Jet Trader]

mmmh, I caculated the max defl rate myself (50

[WarpD 824]

>mmmh, I caculated the max defl rate myself (50

[Guest DC-8 Jet Trader]

I was kind of thinking something with a kind of aspect ratio etc. I've tried hundreds of things ...Thx for the heads up

[WarpD 824]

Do you know WHAT Cd_df is?

[Guest DC-8 Jet Trader]

Cd: drag coefficientdf: flaps dragSO if these get out of a windtunnel test, how/where can I find/buy a document containing these results?...

[WarpD 824]

I would ask why you thought you should change what was already there to begin with.All coefficient values are usually fractional in range.To set appropriate values without anything fancy, you need data tables that give you the stall speeds for clean, and specific flap settings. You'd use those values to calculate how much drag the flaps would generate per radian of extension.

[Antonio Lapa Gomes 0]

Hi DC-8 Jet Trader,Perhaps this search on google might help you?http://www.google.pt/search?q=Cd%3A+drag+c...lient=firefox-aJust check the link for the 1st pdf it looks interestingand also check other links, you might find something that will help youBest regardsAntonio Lapa Gomes

[Guest DC-8 Jet Trader]

I would change it because the dynamics that already exist are based on wrong data. A small example is that the engines are not configured for JT3B but for CF56 engines ...That's why we are making a brand new one.I've been checking google for some while now and haven't really found what I need ...I got all performance charts with cleanspeeds etc included. So if you can tell me how to calculate several lift and drag coefs for flaps, I would highly appreciate it ...

[WarpD 824]

Rule #1 for an .air file: "Change only that which you can confirm is incorrect."As for how to calculate lift/drag... aerodynamics formula is what you require. Google is the source. ;)