FSX model is limited in modelling prop effects. It is actually a bit more limited since at least one record that could be used for fine tuning was truncated in the fs9-fsx transition...

I believe MFS uses a more sophisticated approach, of the same "style" used by XP.

Hope they no longer ZERO torque above VFe, as in FSX...

 

 

Its not bad, personally i think XPlane still does a much better job. i like the wind buffeting on GA aircraft, but if you set TO trim to the locations in the GA aircraft (I dont bother with the tubes, too broker right now) they rotate too fast, they dont climb out at the correct speeds etc, Its a decent attempt and im sure it will get improved.

1 hour ago, jon b said:

A truly fascinating discussion.

Perhaps it’s just a placebo effect but in the context of sd_flyer’s comments above about unloading the nose wheel...I’m finding I can replicate the technique for a soft/short field take off in the Cessnas much better than in any other sim I own.

That is to hold back pressure during the take off role to get the nose wheel off the soft ground ASAP let the aircraft get airborne prematurely then lower the nose to stay in ground effect while accelerating to an appropriate climb away speed. This simulator  does all of that perfectly and allows me to use the techniques I was taught bush flying in the Australian outback. I’m loving it, it’s bringing back great memories 

now this is very interesting. I tried short field takeoff in the C172 using what I do IRL in the PA28 (exactly the same as you described above). In the real plane I really have my yoke as aft it can be -my knuckles are white, however my beloved C172 in MSFS wants to tailstrike something a PA28 doesnt do all that easy. You must have a really bad day if so...

What am I doing wrong in the cessna?

2 hours ago, Slides said:

You keep basically calling the CEO of Asobo a liar and then act hurt and surprised when people ask for proof.

Shockingly, the rest of your comment tells me that you don't actually understand the basics of inputs and outputs from a model.

You've said that before and it is utterly untrue. The only person getting upset is you. I don't have an agenda for or against anyone.

But continuing the subject, not personal attacks: You can tune the legacy and modern flight models to produce virtually the same behaviour. The multiple lift points do exist, but are currently expressed (as documented by the SDK) in debug mode and as reference.

There is a system whereby you can enter dimensions and weights and the physics engine will come up with a flight model based on them, but the output parameters still use the standard text cfg file with the values adjusted for those dimensions and weights.

As far as I know, no-one has published a model based on that, but perhaps they will shortly.

On the 3d animations vs flight model, a limited number of changed flight model parameters (for example the elevator total authority or rudder elasticity) are reflected in the animations, but not the other way around. In other words, the animations do not influence flight behaviour, but the flight behaviour can trigger the animations.

 

Edited September 3, 20205 yr by robert young

1 hour ago, L3m0n said:

You should read through the SDK. There is a section that is all about the FM and explains some of the requirements. Evidently MS wanted the new flight model to be compatible with the old one, so that a ported FSX aircraft would perform the same in normal flight. But the newer FM, basically using the same parameters as the old, would improve the FSX aircraft on the edge/near stall. 

The documentation gives a pretty good idea of how all this works although its not complete yet. There are also some obvious things that need to be added to the new FM but it already is estimating lift/drag across a ton of different points, something like 80 per wing.

I have read the SDK, several times.

10 minutes ago, robert young said:

You've said that before and it is utterly untrue. The only person getting upset is you. I don't have an agenda for or against anyone.

 

What's untrue? You doubting what the CEO of Asobo has stated about the new flight model? You've been shown his tweet before. But instead of acknowledging that, you continue to make your claims and provide no proof for them. Instead you even made a claim that Asobo themselves said their new flight model was not implemented but have never produced proof this.

It's not a personal attack to hold you accountable for your claims. Not sure why you think that. Don't get defensive. Provide proof.

13 minutes ago, robert young said:

The multiple lift points do exist, but are currently expressed (as documented by the SDK) in debug mode and as reference.

You need to really understand the meaning of debug mode then.

@SAS443

Firstly I’m glad you concur with my technique, it’s been a few years for me since I last used it.😉

I’ve been doing this solely from inside the cockpit and balancing the stick Once the nose comes up to get that sweet spot of nose in the air but avoiding it coming up too far and getting a tail strike .

However, having just checked out the same routine in the external view,which I’m presuming is what you’ve seen, you’re right the tail is scraping the ground, it looks like there’s too much elevator authority at such a low speed.
It seems that some if not all of that authority is exaggerated by adding prop wash. Coast along  at slow speed below an estimated 20kts with power off and I’ve found you don’t have the authority to get the tail to strike, give it a blast on the throttle and the nose instantly rises however.

Again going at almost walking pace riding the brakes To stop it accelerating  with full aft stick adding a blast of throttle  and the instant prop wash allows the elevators to scrape the tail.

So, I’d suggest that’s our culprit here , excess prop wash effect over the elevators. 
perhaps someone more current on the 172 than me can confirm it’s behaviour, I seem to remember pulling prop wash induced wheelies in the 152 for fun, but perhaps not as easily as this.

1 hour ago, roi1862 said:

With all the being said, which i do not disagree, maybe someone with more experience can explain how come non of the GA aircraft needs a rudder input to stay coordinated at any stage/speed/altitude/rate of turn ? 

FWIW, this was pointed out months ago in the Alpha testing. 

The more you look, the more issues you'll find that indicate this is still very much a work in progress. At least I hope it is, and Asobo isn't just leaving it up to 3rd party payware to fix things.

For example, the sim does not appear to model adverse yaw with one engine failure in a twin. Cut the fuel for one engine in an XP11 twin, and you'll need a strong rudder input to maintain heading. Especially if it's the "critical" engine. Doesn't happen in MSFS. You can maintain heading straight and level with one engine out, and no rudder input at all.

Now, that may not matter for people who use the sim mainly for sightseeing because you'll never get an engine failure unless you want it. For anyone practicing "what if" scenarios, and trying to learn about how things work in the real world, it matters.

 

2 hours ago, Slides said:

Shockingly, the rest of your comment tells me that you don't actually understand the basics of inputs and outputs from a model.

What is shocking is You not knowing that Robert Young was 1/2 of RealAir Simulations Ltd.
The company that produced some of the best ever addon airplanes made for FSX.
btw: Many of us ported them to P3D v4 & v5.

Just now, RamonB said:

What is shocking is You not knowing that Robert Young was 1/2 of RealAir Simulations Ltd.
The company that produced some of the best ever addon airplanes made for FSX.
btw: Many of us ported them to P3D v4 & v5.

I know who he is. That doesn't mean he's right or infallible. 

2 minutes ago, jon b said:

I’ve been doing this solely from inside the cockpit and balancing the stick Once the nose comes up to get that sweet spot of nose in the air but avoiding it coming up too far and getting a tail strike .

However, having just checked out the same routine in the external view,which I’m presuming is what you’ve seen, you’re right the tail is scraping the ground, it looks like there’s too much elevator authority at such a low speed.

I wonder if that's the flight model or your control settings? Are you using a linear sensitivity setting or a curve? You might need a curve to duplicate the control deflection you're used to, for raising the nose.

 

2 minutes ago, Slides said:

I know who he is. That doesn't mean he's right or infallible. 

Well then; if You don't mind.  I'll still trust him a bit more than You.

1 minute ago, RamonB said:

Well then; if You don't mind.  I'll still trust him a bit more than You.

I'll trust the CEO of Asobo and other people who have looked at the SDK even more.

1 hour ago, roi1862 said:

Yep. I am surprised non of the more professional pilots here didn't mention it.

To busy flying the Longitude to notice.  To the point if all the GA's don't require some coordination in turns there's another legitimate problem that needs addressing (some planes require less than others)...