What to change to make

[Guest]

My MD82 is behaving as if it was a Cessna when landing. It floats very long and this happaends at any speed, with/without flare.Would be nice if someone can give me a hint. I have Aircraft Airfile Manager but to be honest I can't do much with it.

[Guest Eugen]

Hi,You could perhapps try to download another md 80 aircraft and rename the aircraft cfg file. http://www.scandva.org/fleet/md8123/md8123.htmor try the Stellan cfg file in his package for DC 9-41http://www.bahnhof.se/~classic/brgdsEugen

[Guest]

Been using them booth. Actually it's a rework of the sva MD82 I'm using. My callsign is "SAS550 " :) Stellans make aircraft behave very strange when Yaw damper is off. Maybee I shoud go and check his FAQ.

[Guest Douglas K]

If you are using the SVA MD82 CFG and .AIR files, I notice the flaps sections in the CFG file aren't complete - see below:[Flaps.0]type=2span-outboard=0.800extending-time=7.000system_type=1damaging-speed=250.000blowout-speed=300.000lift_scalar=0.000800extending-time=7.000system_type=1flaps-position.0=0.000000,0.000000flaps-position.1=17.000000,0.000000flaps-position.2=17.000000,0.000000flaps-position.3=17.000000,0.000000flaps-position.4=20.000000,0.000000flaps-position.5=20.000000,0.000000lift_scalar=1.0drag_scalar=1.0pitch_scalar=1.0damaging-speed=250.000blowout-speed=300.000[Flaps.1]type=1span-outboard=0.500000extending-time=47.000000system_type=0flaps-position.0=0.000000,0.000000flaps-position.1=0.000000,0.000000flaps-position.2=11.000000,0.000000flaps-position.3=15.000000,0.000000flaps-position.4=28.000000,0.000000flaps-position.5=40.000000,0.000000lift_scalar=1.0drag_scalar=1.0pitch_scalar=1.0damaging-speed=250.000blowout-speed=300.000Looking at the airfile with AirED I see the Cd_df Drag Coefficient- Flaps is pretty low at 150, even the default 737-400 is set to 229 and in combination with the very low Cdo Drag Coefficient-Zero Lift of 31 it will result in just the flight behavior you describe - the aircraft won't slow down - even with the flaps fully extended!You can improve matters by using the Flaps.0 and Flaps.1 sections shown above to which the lift_scalar=1.0, drag_scalar=1.0, and pitch_scalar =1.0 sections were added. Just delete the old sections and copy and paste the sections above to the CFG file.Then if you can use AAM or AirED even a little, you should increase the Cd_df Drag Coefficient-Flaps from 150 to at LEAST 230 for AirEd; if you're using AAM increase the value from 0.07324 to something like 0.12181.Or..... (and much easier if it works) you can increase the flaps drag_scalar in the CFG file from 1.0 to a higher value (try 1.5 or 1.7 to start), and then flight test to check the change that you made.Continue using one method or the other and flight testing until you are satisfied with the results.Happy Landings!

[Guest]

Tnx. I guess this is the info I'm looking for. It's late now here in Sweden 11:44 pm so I'll check this out tomorrow. Once again Tnx.

[Guest]

Been testing a little now and it seems like it has no effect on the float. Is there an entry for the ground effect aswell?

[Guest Douglas K]

Anders,Look in the airfile for TBLDB 400 Wing dCl/dAOA vs Relative Height (in both AirEd and AAM), it concerns ground effect. But let me say that after flying this A/C with no modifications whatsoever (which is what I should have done before running my mouth about the flaps drag coefficient being too low), I find that I can't duplicate the float that you describe even with only 6000 lbs of fuel onboard. You may be using a excessively high approach speed (although you mention that it happens at ANY speed) -or perhaps it just flys differently on my computer- but I really can't fault this A/C with regard to drag or float during landing.If you want, you can try editing TBLDB 400 by lowering the Y values slightly. Also, in Rec 1101 there is an entry called CL_de Lift-Elevator that may have some effect if you lower the number found there.However, it looks to me like you should return the flaps sections in the CFG file to the way they were, especially since it had no effect on the problem for you (when I increased the flaps drag scalar in the CFG file to 1.5 before flying the A/C this morning it took about 85% N1 to maintain 130 KIAS with flaps 40 and a descent rate of 600 FPM! And it definitely didn't float at all with the thrust levers at idle), or put the airfile flaps drag back to the original value of 150 if you edited that instead of the CFG file. I would do that before fooling around with lift coefficients and ground effect tables.I hope you get it sorted out, but at this point I gotta admit I'm kinda baffled!

[Guest]

I guess I'll fiddeled to much with it. Going back to the original one now. I still think it floats to much. I tried the 737-400 default AC *.air and the behavior was better. At least in the touchdown part. But the eyepoint was way to high together with the md82 aircraft.cfg.Tnx for the help I've learned alot.