More Physics, More Real Winds

Jorg Neumann Says in the interview, that FS2020 has a super realistic flight model… (at 11:12 minutes of the interview.) Now if we have pilots on this forum that are super realistic about the super realistic flight model… Then I guess your professional opinion should get paid, as you have the time to fly a super realistic flight model and keep flying with all the bugs… Now… If that is not an understatement to your professional experience and your maturity… Then I guess we should all buy X-box and start flying our super realistic experience with our extraordinary preception of hopes for the next version of Flight Simulator.

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That one came to a sad ending but fortunately no one was hurt.

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Hehe that vid is fun. It’s what I do to get the aircraft off with the Carbon Cub and the Grravel: pop the flaps to get airborne, then put them back up to get away…

Really smoothly putting us back on the topic of crosswind :joy:

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I did? Oh yeah. I didn’t notice! :laughing:

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I took an afternoon but I have found one of the problems with the MSFS flight model:

Edit: I think I found atleast one of the issues, when looking at the elevator deflection it is somehow depending on the airspeed, so full back sidestick at Vmo only means a few degrees of elevator deflection. I think this is due to another “improvement” they’ve incorporated to make make planes behave more “realistic”. I believe this was explained in some developer Q&A, but I can’t find it.

They’ve explained something like, its harder in real life to pull the stick full back due to the feedback from the flight control system and G-forces so they’ve limited something. Just tested on the Cessna 172, exactly the same thing going on, no full elevator deflection at high speed. This would explain the weird stall dynamics and inability to pull the aircraft in an accelerated stall, it does however not explain or solve the sensitivity issue.

The implementation is done very poorly, to the point that you can’t even stall an aircraft anymore, can’t maintain altitude during a 45 or 60 degree steep turn etc. From the video below, you can see the elevator deflection above my mouse pointer. When inside the cockpit you have no hind that this is even happening as the yoke position mimics your joystick position and is unrelated to the actual elevator position!!! Not how it works in real life at all of course, totally unrealistic.

Asobo, please, please remove this or make it an option!!!

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Nice find. Never would have guessed.

Agreed, excellent work is being done here, many thanks.

Something else interesting I found is that the elevator trim on for example the Cessna, does not change elevator position or yoke position in the cockpit. The aircraft does climb or descent when trimming up or down, my question is how? When the elevator itself is not moved the trim tab should work OPPOSITE from the elevator and trimming up will move the nose down and vice versa. How can they simulate the pitch trim without moving the actual elevator?

How does this work on other sims? It seems it doesn’t really matter what you dive into, with FS2020 you will always end up at something that doesn’t work…

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Is the CP moving when you adjust trim?
How about the length of the thrust vector on the hor stab? Does it change length? Is it possible they are changing the actual lift coefficient of the stablizer? Trim down and the tail’s lift is increased, trim up and the lift is decreased?

This feature has been already there (at least) since FSX.
It was e.g. essential to use in Bf109 flight dynamics where the elevators tend to freeze at high diving speeds.
Since you can’t restrict the joystick travel, this is the only possible workaround.

Haven’t tried, but in MSFS this is most likely the elevator_elasticity_table in the flight_model.cfg

Does this perhaps [attempt to] simulate control surface aerodynamic load? I.e. the ability for the pilot to physically actuate the controls? Whether this is realistic or not is another question.

Being unable to ‘fly’ using trim is more concerning. Is this the same for all aircraft or unique to the Cessna [172]? I haven’t fired them up for a long time now, but I believe elevator trim did effect pitch in previous titles?

  1. Yes

  2. Trim works as it should. The point is that if the horizontal stabilizer isn’t used for trimming (like in the Piper Super Cub) and the elevator doesn’t change its position when trimming (as it would when trimming IRL) how does MSFS achieve/simulate trimming?

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My apologies - for some reason I read Nijntje91’s post to mean that elevator trim was not effecting pitch.

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Just to clarify, it’s the following you’re referring to right? Not questioning you, just making sure i’m on the right page here :joy:

elevator-trim-tab

Accompanying text:

‘If the pilot wants to pitch the nose of the aircraft up, he pulls back on the control column which deflects the elevator trailing edge upward, producing a downforce at the tail which raises the nose. The pilot then trims the elevator to hold that deflection angle. The trim tab deflects downwards, causing a lifting force on the tab, which produces a moment at the elevator hinge equal and opposite to the moment generated at the hinge by the elevator force. The elevator position is held by the force generated by the tab and the pilot is able to relax the pressure on the control column.’

Pinched from here: Aircraft Tail Surfaces and Trim | AeroToolbox

Visually it doesn’t appear to from what I can see. With trim applied, the elevator appears to return to it’s neutral position with no control pressure from the yoke.

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Exactly! The only thing the trimtab does is move and hold the elevator in the required position. The MSFS way of trimming would never work in real life, if the elevator itself is not moved, the trim tab will start to act like a small elevator, not having much pitch authority considering its only a very tiny surface and actually working in reverse. In your second picture you can see the trimtab deflected down with the elevator neutral, in real life this would actually pitch the nose DOWN and not UP (it is supposed to move the elevator UP which in turn pitches the nose UP).

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this has long been known about and many sims suffer from it and there really is no elegant solution for pure mechanical linkage.

as if they made a fixed relationship the visual yoke and the elevator, then you would see the yoke move back towards centre as airspeed gets to higher levels which would create a visual disconnect between your hand on your desktop joystick/yoke and the visual yoke in the 3d cockpit.

an alternative would be to have max base deflection take place at 50% of your desktop joystick/yoke movement, and then have the later 50% of the axis represent “force” so as the visual yoke in the 3d cockpit and the 3d elevator starts trending back to centre you start using the latter 50% of the axis to stop the trend to the centre representing your “force”, but then this would be unintuitive for many.

I agree, but it still leaves the question, how does MSFS trim without a trimmable horizontal stabilizer and without moving the elevator? The picture @LincolnSixE posted above also makes zero sense.

I would think the disconnect between your hardware and the “in-sim” yoke to be more realistic. i.e. when trimming full down and then move your joystick full down nothing happens as the in-sim yoke is already full down, the disadvantage would be that the neutral to full back now represents the full elevator range until back in trim. Is there any sim which works like this? I’m interested to know if this would be more realistic.

That’s basically how it works in DCS, honestly in practice both ways “feel” about the same when trimming out pressure.