DmitriKozlowsky Posted June 10, 2024 Posted June 10, 2024 THere is definiely a yaw control problem in M2KC right now on T/O and landing. At T/O the aircraft veers to left reagrdless of rudder and NWS, and veers to right on landing regardless of rudder and NWS. IMHO the cause is a combination of gross weight and ground speed. The problem manifests itself at high T/O weights, and higher the 'allowed' landing GW weights. The problem occurs on ground between above 40 knots , when NWS, shiuts off, and 100 knots, before rudder has yaw effect. It is within that range gate of ground speed that steering control on ground is lost. I beleive this is a bug in flight model and ground handling. Possible solution On T/O. Do solo T/O. Place A/C on right moddle of runway threshold, with nose pointed towards right side of RWY at 5 degree angle. Go to gull burner. RIGHT FULL RUDDER. The aircraft will veer to left, but will gain speed to above 100 knots where rudder will have effect. Above 125 knots ROTATE. Full rudder authority is now available. Above 135 to 150 knots, depending on GW, the A/C will unstick. Its a messy weird T/O but it works. Mostly. On Landing. Expend all ordinance, and bring fuel below 1200. Bingo light will go on and low fuel horn will sound. Fly ILS glideslop at 150 lnots at 10 AOA. Touchdown with 135 to 140 knots gently 12 - 14 AOA. DO NOT POP drag chute. Keep nose up and nose gear off runway for as long as possible. Below 60 front gear will come down on its own. Now pop chute , actuvate NWS, and wheel brake. The aircraft may veer to right, but will slow down to below 40 knots and NWS will have full authority. When ground speed dispappears from HUD,the aircraft is below 40 knots. This approach may not be applicable to short fields in South Atlantic or road strip landings. Not untill steering and ground handling bug is fixed.
FusRoPotato Posted June 13, 2024 Posted June 13, 2024 This is a really old bug. Are they not obligated to fix this even though they got paid for it?
DmitriKozlowsky Posted June 14, 2024 Author Posted June 14, 2024 19 hours ago, FusRoPotato said: This is a really old bug. Are they not obligated to fix this even though they got paid for it? Of course they are obligated. But obligation is different from fullfillment.
DmitriKozlowsky Posted June 14, 2024 Author Posted June 14, 2024 On 6/13/2024 at 3:25 AM, FusRoPotato said: This is a really old bug. Are they not obligated to fix this even though they got paid for it? How old? This kind of P/O's me. Right now, there is no safe way to safely T/O from Nellis with two drop tanks, centerline BAP-18 rack, 2 X R550, full internal. On takeoff run, above 40 lnots, after NWS shuts off, and before rudder gains authority at 100-120 knots, the aircraftr veers left off the runway. There is no way to arrest this behavior. Not one that I have come across. Right full rudder is not effective. Right wheel brake is not enough. The aircraft just goes left and off runway. Its nuts. I don't recall this behavior a year or 1 1/2 years ago. SO when did it appear.
FusRoPotato Posted June 14, 2024 Posted June 14, 2024 I looked up some old patch notes I wrote for some server mission changes that I removed the wind because the M2000's couldn't take off with even a slight amount of crosswind. This was back in Feb 2023, but this was also the time I bought the module to notice it, so I have no idea how much earlier the problem started. I just know that it's an old problem. Depending on the wind and runway, you can sometimes yank the stick back early and make the front gear hop a little. When this happens, you can get some authority back. It's as if the front tire touching the ground magically makes rudder forces go away.
FusRoPotato Posted June 23, 2024 Posted June 23, 2024 (edited) I can pull back on the stick to releieve nose wheel force and get some minor control authority around 70kts. When the nose gear finally comes off the ground I get sudden strong yaw authority back. It behaves like the NWS is not actually turning off or relaxing, but rather forcing a straight alignment of the gear. However, at the same time, this doesn't explain how slight crosswinds are completely overpowering the yaw authority. When a crosswind occurs, such as left to right, the plane veers right off the runway with full left rudder. At the same time, that kind of crosswind should be causing left yaw regardless because the aircraft is yaw stable in flight. In fact, once the nose gets off the ground, the plane switches from right yaw to left. Maybe a better assumption is that somehow weight on the nosewheel is reducing the vertical stab and rudder aerodynamics. I wouldn't find it hard to imagine that the yaw moments produced by both the gear and the rudder are packed into a total moment before being sent to the statespace integrator. The weight on the landing gear is probably supposed to reduce the gear moment contribution based on speed, but is mistakenly reducing the entire package of moment forces instead. Edited June 23, 2024 by FusRoPotato
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