June 3, 201214 yr Hello folks, I think I've found a minor issue with the rudder trim. Look at the screen: I've applied full left rudder trim. The plane naturally yaws and then rolls to the left, but the trim tab animation is inverted. It is supposed to move to the right instead. Same behaviour on the Turbine Duke. Am I missing something?
June 3, 201214 yr Yup... That's how trim tabs work, they act upon the moving surface itself. Dr Zane Gard Sr Staff Reviewer AVSIM Private Pilot ASEL since 1986 IFR 2010 AOPA 00915027 American Mensa 100314888
June 3, 201214 yr Moderator Sorry Zane, but that is incorrect. When a trim tab is employed, it is moved into the slipstream opposite to the control surface's desired deflection. For example, in order to trim an elevator to hold the nose down, the elevator's trim tab will actually rise up into the slipstream. The increased pressure on top of the trim tab surface caused by raising it will then deflect the entire elevator slab down slightly, causing the tail to rise and the aircraft's nose to move down. Likewise, a rudder trim tab's movement is always opposite the rudder's desired direction... ...so the OP is quite correct. The model's animation of the trimtab is inverted. Of course, truth be told most models I've seen in FS are likewise incorrectly animated. :Nerd: Fr. Bill AOPA Member: 07141481 AARP Member: 3209010556 Avsim Board of Directors | Avsim Forums Moderator
June 3, 201214 yr Author So do you agree with me that the animation is inverted, since the "real" tab moves into the slipstream opposite to the control's surface desired deflection.
June 3, 201214 yr The trim tab should move in the opposite direction to the desired rudder position. If that is not happening it is a mistake, but really a very very very very minor one, compared to the potential for a lot of other mistakes. Thanks for pointing it out. I don't think it will ruin my Sunday though. ;) Rob - RealAir Robert Young - retired full time developer - see my Nexus Mod Page and my GitHub Mod page
June 3, 201214 yr Moderator So do you agree with me that the animation is inverted, since the tab moves into the slipstream opposite to the control's surface desired deflection. Yes, I do. I was (re)editing my reply when you posted this... :Peace: Fr. Bill AOPA Member: 07141481 AARP Member: 3209010556 Avsim Board of Directors | Avsim Forums Moderator
June 3, 201214 yr It looks like the tab is moving opposite, that is correct. Dr Zane Gard Sr Staff Reviewer AVSIM Private Pilot ASEL since 1986 IFR 2010 AOPA 00915027 American Mensa 100314888
June 3, 201214 yr Author No, in my screenshot the tab is on the left side. It is supposed to be on the right side. Anyway, Rob... no problem at all. Just found this comparing with Lancair Legacy animation, which is correct indeed. :Peace:
June 3, 201214 yr The shot is taken from right behind so it's difficult to see which way round everything is. Anyway, the tab should move opposite from the intended movement of the rudder itself. I think we all agree on that. Rob Robert Young - retired full time developer - see my Nexus Mod Page and my GitHub Mod page
June 3, 201214 yr Author The rudder is neutral in the screenshot (obviosly in reality it should be slighty on the left, with the tab on the right). Situation in the 2 screens below: * Rudder pedals are neutral * Full left rudder trim Lancair Legacy (correct animation): Trim tab on the right, consequently rudder on the left (without applying rudder!) Haven't seen other planes replicating this... usually only the tab moves. Great job Rob and Sean! Beechcraft Duke (wrong animation): Trim tab on the left, rudder neutral. Hope is clear now. Apologies for my english.
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