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NikolaiVChr / MB339

Aermacchi MB-339
GNU General Public License v2.0
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Aero #1

Open NikolaiVChr opened 4 years ago

NikolaiVChr commented 4 years ago

@kvnjonathan70 this is what I used to generate the FDM using AeromatiC++ It didn't fly very well, but I got sidetracked by other projects, so didn't work any further on it.

system of measurement: metric Type of aircraft: military trainer wing shape: straight CoG clean = 23 to 31 % MAC stall, clean, level, flaps up = 70 KIAS = 130kmh (I doubt this low number) empty weight = 3430 Kg Wingspan: 10.86 m Length: 10.97 m Wing area: 19.3 m2 quarter-chord sweepback: 8° 29' = 8.48333 degs max takeoff weight: 6150 kg Aspect ratio: 5.26:1 (not sure if this is more accurate than the one I calculated) aspect: wingspan^2/area = 6.111 taper: tip/root = 0.598 root: 2.24 m tip: 1.34 m incidence: 0 degs? dihedral: 3.44 degs vtail arm: 3.97 m vtail area: 2.34 m2 htail arm: 4.6 m htail area: 4.12 m2 Rolls-Royce Viper MK680-43 idle N2 = 40.5 max N2 = 103.5 KN = 19.05/19.394 bypass ? overall pressure ratio: 4.3 pressure ratio: 6.75:1

kvnjonathan70 commented 4 years ago

Thanks for the information.

kvnjonathan70 commented 4 years ago

hi Niko ! I have a doubt, would you mind clearing it ? I see that the CG and aeroRP is not same in you a/c configuration file, does it mean that you have considered aerodynamic center as aeroRP ?

NikolaiVChr commented 4 years ago

I placed CG so it was in a somewhat sane position in relation to the main gears. Then I think I used the 5% rule of thumb to place AeroRP. The 5% rule says: for stable aircraft the static margin should be around 5% MAC. Static margin in case you dont know, is length between the neutral point (average between Aerodynamic center of wing and horiz. tail.) and CG.

kvnjonathan70 commented 4 years ago

thanks Niko :)