Spanky Posted May 10, 2013 Posted May 10, 2013 I posted this in the 3rd Party thread but I thought I'd echo it here for a larger audience view.. :) "I'm having some issue with the BD-5 flight model. We're trying to make the best of the SFM currently and have made significant headway with a lot of the flight model, with exception to one thing. Pitch control! The BD-5 has a small weight 170Kg empty and a low wing area of just 11.34m2 The issue we're coming across is that regardless of what values get changed in the SFM area, (Mzalfa, Mzalfadt, Cya, Akldop and Cymax) nothing seems to provide us with a change in pitch authority. Full elevator deflection results in about a 1.5 - 2G climb at best at about 200KIAS. I should be getting far more authority than that. Is there an pitch coefficient or multiplier which can increase the pitch effectiveness? I'm trying to figure out what might be causing the restriction in pitch moment, but it's driving me nuts.. Any thoughts would be great. I've checked various forum posts relating to aerodynamics with no avail. "
SVKSniper Posted May 10, 2013 Posted May 10, 2013 (edited) Spanky i have similar problem with AOA....Max value for AOA I reached around 5....And value of G did not move from 0... In myplane.lua i see this: AOA_take_off = 12, -- AoA in take off (for AI) Edited May 10, 2013 by SVKSniper Support my work
Spanky Posted May 10, 2013 Author Posted May 10, 2013 My issue I think we've managed to narrow down (thanks to Chris at CoreTex) is down to the empty, nominal and max weight values of the aircraft. Once I altered to a larger weight, I had no issue.
SkateZilla Posted May 10, 2013 Posted May 10, 2013 (edited) All of the modules I'm working on have Pitch Authority issues, Especially Takeoff/Landing and below 3-5000~ish Feet. I notice the same behavior on the F-15C from FC3, but the private modules are way more pronounced. No matter what I changed the value to, If I Pull back on the stick, I only get like 15% Max deflection, like a Pitch Input Dampening/Handicap is being applied. Started with 1.2.3 for me, before that I had no issues w/ pitch. I also was able to drop M_max and M_fuel_max to get better results, but no where near the authority/performance I had before 1.2.3 The VRC F-16 AFM Demo doesn't have this problem, so it's a SFM issue somewhere. Edited May 10, 2013 by SkateZilla Windows 10 Pro, Ryzen 2700X @ 4.6Ghz, 32GB DDR4-3200 GSkill (F4-3200C16D-16GTZR x2), ASRock X470 Taichi Ultimate, XFX RX6800XT Merc 310 (RX-68XTALFD9) 3x ASUS VS248HP + Oculus HMD, Thrustmaster Warthog HOTAS + MFDs
Spanky Posted May 11, 2013 Author Posted May 11, 2013 SkateZilla, I'm seriously thinking of trying EFM, SFM just doesn't like to play with a lot of things and I think the general consensus is a move to EFM for add-on 3rd party mods. I think Alex is on hols at the moment but I'll be bringing the SFM issue up with him when he gets back to at least see if it's an engine code thing or a stupid spanky thing.. :)
SkateZilla Posted May 11, 2013 Posted May 11, 2013 SkateZilla, I'm seriously thinking of trying EFM, SFM just doesn't like to play with a lot of things and I think the general consensus is a move to EFM for add-on 3rd party mods. I think Alex is on hols at the moment but I'll be bringing the SFM issue up with him when he gets back to at least see if it's an engine code thing or a stupid spanky thing.. :) I dont want to speculate on ED Changing anything, cuz, I honestly cant prove it, other than the behavior of everything under SFM now vs the way they were before 1.2.3. My only argument is the A-10C, and the F-16C Demo Smiley did do not suffer from pitch issues, while the F-15C, and every other SFM Based module I have does to a certain extent, with some being more apparent than others. Windows 10 Pro, Ryzen 2700X @ 4.6Ghz, 32GB DDR4-3200 GSkill (F4-3200C16D-16GTZR x2), ASRock X470 Taichi Ultimate, XFX RX6800XT Merc 310 (RX-68XTALFD9) 3x ASUS VS248HP + Oculus HMD, Thrustmaster Warthog HOTAS + MFDs
VincentLaw Posted April 13, 2014 Posted April 13, 2014 (edited) Okay, basically this thread. Has anyone figured out a way to alter pitch authority in the SFM? I can't find a way to specify elevator size or any related coefficients. The Mzalfa coefficients just specify the stabilizers, not the control surfaces. Update: I tried moving the center of mass back and it still rotates for takeoff at the same speed. Strangely enough, increasing the nominal mass reduces the speed required for rotation, but it also messes up the longitudinal stability in flight. That also seems like a really hacky way of doing it. Edited April 13, 2014 by VincentLaw [sIGPIC][/sIGPIC]
RedBeard2 Posted April 15, 2014 Posted April 15, 2014 (edited) What kind of max AOA do you need and have you updated Aldop for that max AOA? Edited April 15, 2014 by RedBeard2
VincentLaw Posted April 15, 2014 Posted April 15, 2014 What kind of max AOA do you need and have you updated Aldop for that max AOA?Angle of attack is fine. I am just trying to get a shorter takeoff run. I want rotation to occur at a lower speed, which should be related to pitch authority. [sIGPIC][/sIGPIC]
RedBeard2 Posted April 15, 2014 Posted April 15, 2014 Also, Cya and Cymax are related. Do you get to Cymax before your Aldop departure point is reached? Mzalfa is tail pitch coefficient, Mzalfadt is wing pitch coefficient. Lastly, kjz is related to the elevator control power coefficient in some way but it is not obvious to me yet. See my aircraft mod guide for descriptions. There's also some threads around that discuss what happens where some of these values vary.
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