honey151 Posted November 12, 2014 Share Posted November 12, 2014 load and refuel each time heavyer bug looks like fixed,but new bug come out,why when i land,nose wheel have left right move......this is coming out when speed drop 200KM/H low,sometime get nose wheel bowl......Of course not hard landing,i land smooth,speed not high,every button on right side,every control is normal.....nose wheel just Swing when speed drop 200km/h,when bad luck,it's bowl......i have to repair or restar or quit......even this is game plane,i don't want crash it,i don't want sit the desk behind,see lots document every day...... Link to comment Share on other sites More sharing options...
golani79 Posted November 12, 2014 Share Posted November 12, 2014 In which position is your nosegear brake lever? Haven´t encountered such a behavior yet. >> DCS liveries by golani79 << Link to comment Share on other sites More sharing options...
honey151 Posted November 12, 2014 Author Share Posted November 12, 2014 In which position is your nosegear brake lever? Haven´t encountered such a behavior yet. on the left Link to comment Share on other sites More sharing options...
dragosmur Posted November 12, 2014 Share Posted November 12, 2014 (edited) Same problem here. On runway I reach 150 km/h, then throttle to idle. The nose wheel starts to move to left and right and gradually gets worse. It happens no matter in which position the nosegear brake lever is. One mention. I have 5m/s crosswind. Haven't tested without crosswind yet. Edited November 12, 2014 by dragosmur Link to comment Share on other sites More sharing options...
TurboHog Posted November 12, 2014 Share Posted November 12, 2014 load and refuel each time heavyer bug looks like fixed Don't think so at first glance. Will test properly later. 'Frett' Link to comment Share on other sites More sharing options...
honey151 Posted November 12, 2014 Author Share Posted November 12, 2014 Same problem here. On runway I reach 150 km/h, then throttle to idle. The nose wheel starts to move to left and right and gradually gets worse. It happens no matter in which position the nosegear brake lever is. One mention. I have 5m/s crosswind. Haven't tested without crosswind yet. same problem without wind.......god~maybe earth bowl Tomorrow，i want fly mig21 with out bug,this bug is 12.1.1 great,12.1.0 don't have this,but heavy problem..... Link to comment Share on other sites More sharing options...
TurboHog Posted November 12, 2014 Share Posted November 12, 2014 I've experienced the same issue, but only after refueling twice. On the third takeoff run I could barely get of the ground (99% sure the refuel bug fix did not make it to this version) and my nose wheel violently went left to right. Could it be related to the heavy weight? But if you've experienced this on the first loadout then it's a problem. 'Frett' Link to comment Share on other sites More sharing options...
dragosmur Posted November 12, 2014 Share Posted November 12, 2014 I've experienced the same issue, but only after refueling twice. On the third takeoff run I could barely get of the ground (99% sure the refuel bug fix did not make it to this version) and my nose wheel violently went left to right. Could it be related to the heavy weight? But if you've experienced this on the first loadout then it's a problem. You can experience this on runway preparing for takeoff. Accelerate to about 150-200 km/h then move throttle to idle. I had two 500kg bombs, anti-air missiles and center fuel tank. Link to comment Share on other sites More sharing options...
SNAFU Posted November 12, 2014 Share Posted November 12, 2014 I didn´t face this bug yet, so it is not simulated nose wheel shimmy? [sIGPIC][/sIGPIC] Unsere Facebook-Seite Link to comment Share on other sites More sharing options...
dragosmur Posted November 13, 2014 Share Posted November 13, 2014 It seems to happen more when the aircraft is loaded and less when it is empty, although I experienced it after landing also. As honey151 said it is not affected by the wind. In the first two tracks the nosewheel shakes left-right so violently that the tire explodes.nosewheel_bug_windy.trknosewheel_bug_calm.trknosewheel_bug_empty.trk Link to comment Share on other sites More sharing options...
dragosmur Posted November 13, 2014 Share Posted November 13, 2014 Also when accelerating on runway. Different airport.nosewheel_bug_acceleration.trk Link to comment Share on other sites More sharing options...
honey151 Posted November 14, 2014 Author Share Posted November 14, 2014 still not fix this bug?how i can fly....... Link to comment Share on other sites More sharing options...
Random Posted November 14, 2014 Share Posted November 14, 2014 Only had it happen after taxiing across grass or a heavy landing. I assumed I'd broken something! Link to comment Share on other sites More sharing options...
honey151 Posted November 14, 2014 Author Share Posted November 14, 2014 Only had it happen after taxiing across grass or a heavy landing. I assumed I'd broken something! YES,Maybe you are right,today it's not happen,i think it's been fix this update Link to comment Share on other sites More sharing options...
dragosmur Posted November 14, 2014 Share Posted November 14, 2014 (edited) YES,Maybe you are right,today it's not happen,i think it's been fix this update Unfortunately it's still there, although slightly less pronounced it seems. This time the nose wheel tire did not explode from shaking. It is aggravated when the aircraft is heavy loaded, on rough runway and when deccelerating. Accelerating with a heavy loaded aircraft on runway to 200 km/h and then moving the throttle to idle is the simplest way to provoke it. You no not have to use the wheel brakes. I believe that it is caused by applying weight on the front gear.nosewheel_bug.trk Edited November 14, 2014 by dragosmur Link to comment Share on other sites More sharing options...
iFoxRomeo Posted November 14, 2014 Share Posted November 14, 2014 I´d say: fantasic job Leatherneck! Shimmy simulation. Obviously the MiG-21 had no steeringdamper for its frontwheel. Fox Spoiler PC Specs: Ryzen 9 5900X, 3080ti, 64GB RAM, Oculus Quest 3 Link to comment Share on other sites More sharing options...
dragosmur Posted November 14, 2014 Share Posted November 14, 2014 (edited) I´d say: fantasic job Leatherneck! Shimmy simulation. Obviously the MiG-21 had no steeringdamper for its frontwheel. Fox So this is... normal? It reaches +/-70 degrees in left-right oscillation. It is not comparing to this: http://en.wikipedia.org/wiki/Speed_wobble Also the frequency is 0.3-0.5 Hz, nothing compared to 4-10Hz that would be normal. I really think this is a bug. Edited November 14, 2014 by dragosmur Link to comment Share on other sites More sharing options...
iFoxRomeo Posted November 14, 2014 Share Posted November 14, 2014 I consider this as intended. It is more a weave than a shimmy. Best real weave i could find was this motorbike example. Go to t=6:26min... Poor John. Or this computer simulation And combined with your track... one can see how the MiG escalates. I guess it is intended. It looks plausible for me. I experienced weaves on my bike. When it occured, slowly reducing speed reduced the frequency but the amplitude grew. Fox Spoiler PC Specs: Ryzen 9 5900X, 3080ti, 64GB RAM, Oculus Quest 3 Link to comment Share on other sites More sharing options...
dragosmur Posted November 14, 2014 Share Posted November 14, 2014 (edited) It's still strange. In the first video it says that adding weight eliminates the weave. But in the case of the Mig it gets worse when there is a heavier loadout. At least that's what I experienced. And also, because the wheel is behing the rotation pivot, shouldn't friction dampen the weave? Maybe it's intentional but I still believe it needs some tweaking. Edited November 14, 2014 by dragosmur Link to comment Share on other sites More sharing options...
Art-J Posted November 14, 2014 Share Posted November 14, 2014 iFox, that's what shimmy dampers are for, however, to not let shimmy resonate into high amplitude weave. Bikes don't have these, but probably every tricycle plane from light GA ones up to airliners, does. I admire fact that DCS tries to simulate such effects, but something probably needs tweaking in this particular case. i7 9700K @ stock speed, single GTX1070, 32 gigs of RAM, TH Warthog, MFG Crosswind, Win10. Link to comment Share on other sites More sharing options...
iFoxRomeo Posted November 14, 2014 Share Posted November 14, 2014 It's still strange. In the first video it says that adding weight eliminates the weave. But in the case of the Mig it gets worse when there is a heavier loadout... It is a question of the response frequency. Adding/removing weight shifts this frequency. Fox Spoiler PC Specs: Ryzen 9 5900X, 3080ti, 64GB RAM, Oculus Quest 3 Link to comment Share on other sites More sharing options...
iFoxRomeo Posted November 14, 2014 Share Posted November 14, 2014 iFox, that's what shimmy dampers are for, however, to not let shimmy resonate into high amplitude weave. Bikes don't have these, but probably every tricycle plane from light GA ones up to airliners, does. I admire fact that DCS tries to simulate such effects, but something probably needs tweaking in this particular case. I know what the dampers are for. And modern bikes do have them(do you mean dampers or weaving?) both, dampers and weaving. Why does it need tweaking? I don´t have problems with weaving. Just pass the "problematic" speed and thats it. Would you accelerate the aircraft then idle the engine and wait for the weaving in RL? I would not. But again. I think it is intended, but I could be wrong. Fox Spoiler PC Specs: Ryzen 9 5900X, 3080ti, 64GB RAM, Oculus Quest 3 Link to comment Share on other sites More sharing options...
Goggz Posted November 16, 2014 Share Posted November 16, 2014 I'm guessing it ain't a bug, cos it's clear from the video above, that there are skid marks being generated when the wheel oscillates. Nice one Leatherneck, just part of the sim :D Link to comment Share on other sites More sharing options...
ARM505 Posted November 19, 2014 Share Posted November 19, 2014 I'm still not all that sure about DCS's simulation of the interaction of tires and the runway. Not to be be funny, but slip angles, normal force vs friction etc may only be done at a fairly basic level, which could easily exacerbate something like shimmy/weaving. This isn't a racing sim of course, so it's not the number one priority, but still - That video show it at work, it's pretty implausibly modeled there if you ask me. It's like once the wheel is skidding, it's basically riding on ice. Link to comment Share on other sites More sharing options...
nullsys Posted February 3, 2015 Share Posted February 3, 2015 I discovered this recently too. I was able to eliminate the effect somewhat by pulling back 4/5 on the stick. It's annoying to say the least. Link to comment Share on other sites More sharing options...
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