question

Dear Asobo,

I remember this was very easy to do in P3D and FSX days. This was effectively archivable by using the Pitch moment flaps:


Given Alex results and his extensive experience with realistic flight models, it looks like we are now unable to achieve similar results?. Unless there is a way to achieve this that we don't understand?

There are lots of aircraft that behave this way in real world, so it would be good if we can get some ways to control this, specially because as Microsoft Flight Simulator becomes more and more popular (thanks to all your efforts), Aircraft manufactures are becoming more aware of the potential to use MSFS to show case their airplanes and their real world capabilities, and as a result they are imposing to 3rd party developers very tight restrictions in order to grant licensing, some of these aircraft manufactures are now even performing inspections of the flight models we are creating for MSFS and if their required expectations are not achievable we incur into a high the risk to lose the right to even sell these airplanes for MSFS.

I have suffered this myself with TL-Ultralight for the Sting S4 when they were very blunt and told me, no parachute, no release! and I am currently working with other aircraft manufactures who are imposing similar red lines on their contracts with me regarding particular characteristics of their airplanes.

Sensing Alex tone, I am guessing this could potentially become an issue for SWS and they are walking a similar path, specially knowing how proud Pilatus is about their aircraft.

Where I am going with all this? Microsoft and Asobo has done such a great work for this simulator that now Aircraft manufacturers are seeing this as a serious business. This is a compliment to both Asobo and Microsoft, simply put you guys have done just an excellent Job to promote flying simulation to a new level.

Now although this is amazing on one hand, at the same time this means the pressure for 3rd party developers has increased considerably, to a point where we can just lose rights to sell airplanes if we are unable to reproduce certain real flying performance or characteristics of a product.

I am just passing honest feedback on this matter so you guys understand our position a bit better, pretty much sometimes when we post asking for help on these kind of airplane behaviours that we are unable to replicate is a pretty much cry for help since it could mean very bad news for our business.

Thanks one more time to Asobo and the entire team for all the efforts you guys do, we do appreciate everything you guys do.

Kind Regards,
Raul

It is really pulling the nose down hard and gets the plane out of control. If a copy of the flight model file is needed, we'll be happy to provide it.

Edit: the behaviour is reproducable in both SU11 and SU12 beta. Here we have exaggerated parameters to get the plane to respond somehow and -of course- it will spiral out of control.

flaps-position.0 = 0,-1,1,1,1,0,0,0
flaps-position.1 = 15,163,1,1.6,1.07,0,0,7
flaps-position.2 = 30,130,1,3,1.2,0,0,20
flaps-position.3 = 40,130,1,3.25,1.27,0,0,25

The aircraft we are working on will nose down when you apply flaps. During final approach and flaps at 40 degrees, we were approaching to land at a negative AoA to stay on the glide path.

If we try shifting the CG aft, then the actual shift needed is huge and then we have to increase lift a lot to be able to maintain level flight. This causes a lot of other problems and leads the plane far away from its real behaviour. Also, using flaps 40 will cause the plane to go into an uncontrollable nose-dive.

On the other hand, using the "add incidence" parametre doesn't seem to produce any effect until you reach about 3 degrees. At that point, the plane will uncontrollably nose down.

Therefore, the questions are:

1) Do the parametres to shift the CL and incidence with flaps work correctly?

2) If yes, how can we achieve the nose-down attitude that the real aircraft exhibits when extending the flaps?

To add further information to this topic, I think we have hit a weird bug within the core flight model again.

I have modified the flaps to the following configuration, which gives us close to correct approach AoA at flaps 30, but flaps 40 is unusable and the plane nose-dives uncontrollably.

flaps-position.0 = 0,-1,1,1,1,0,0,0
flaps-position.1 = 15,163,1,1.6,1.07,0,1,0
flaps-position.2 = 30,130,1,3,1.2,0,7,0
flaps-position.3 = 40,130,1,3.25,1.27,0,7,0

So at flaps 30 the plane flies close to what it does in reality and the resulting flight behaviour is correct, but having the wing forces applied that far back is a bit... unnatural. As incidence doesn't seem to work, is there another way to make the aircraft fly nose-down with the flaps, other than moving the wing all the way back to the tail?

This is what the sim forces look like with the only known working configuration so far:

Another update to this issue: shifting the CL aft using the offset will still not give us the right result. IRL the plane with full flaps will fly at 5 degrees negative AoA but we cannot get this result without a working pitch moment parameter.

So we come back to the original question: the incidence angle does not seem to work at all. Is it broken or are we doing something wrong? What is interesting is that it worked well in FSX but no longer does.