Based on my experience as a multi engine pilot of many thousands of hours. Prop drag, if it is modelled doesn’t do anything, even on the singles. There is a significant performance change when a prop is fine, coarse or feathered.
Easy proof, get in your favourite constant speed prop aircraft, be it the Bonanza, the Caravan or any of the twins and move the throttle to idle.
Now play with the pitch controls. Any changes when you do?
A windmilling propeller creates significant drag, and a turboprop propeller at idle creates even more.
A stopped propeller can be made to move once the airspeed (in a dive) is sufficient, sometimes a little blip on the starter can get it to spin. This modelling is required before we look into engine failure simulation etc.
Now if you could see thrust/drag vectors from each engine on the aircraft editor that would help prove a lot, and assist designers greatly. 4 vectors per prop (or at LEAST 2: left side and right side of each prop disc) would enable us to really see and control what’s going on.
But I stand firm on my point. Currently propeller drag is not modelled. Can you prove that it is?
Check out any engines.cfg file. Where is the field for propeller drag?
At the very least they’ve either modelled or faked it very well for the 172, because if you configure it for the best glide conditions in the POH you get the expected results from the POH.
Blade angle is measured 1/3 of the span away from the root, as long as angle of attack on that part of the blade is around -3 degrees the drag should be close to zero. But this also depends on pitch, angle of incidence and flying with a slip or skid. The prop will likely not completely stop indeed, especially on free-turbine.
I haven’t had a feathered prop on a freeturbine engine in real life, I have shutdown an engine and feathered the prop on a fixed turboprop engine once and that one perfectly stopped spinning and remained stationary .
Anyway its an interesting observation that the minimum prop angle (called beta for no reason) not only affects performance at idle with the prop on the fine pitch stop, but also at higher power.
Take the G36 at full fine pitch and pull the mixture, establish best glide of 100KIAS, pull the prop to full coarse and watch the descent flatten out, push it back to full fine and watch the descent rate increase again. So the code is clearly in there somewhere, just not fully implemented for whatever reasons.
Power cut at 3000 ft overhead an aerodrome. Mixture cut-off, prop in low RPM, 110 kts at full weight according to the POH it should result in a glide ratio of 1.7 nm per 1000 ft.
Glide range: 4.9 nm
Glide ratio: 4.9 / 3 = 1,64 nm per 1000 ft
I think turboprops are the main problem area. All three are responding like jets when cutting the power. Very slow deceleration, need to start very early reducing speed and throwing anchors out, almost like a jet. Although the Baron also has problems, you could cut one engine, other engine at full power and the aircraft would stall before losing control below Vmca.
The turboprop stuff I leave to people with actual experience like yourself, but the general consensus seems to be that turboprops are broken almost to the point where it’s better to scrub the code and start from scratch.
I am not saying ASOBO dont have aeronautical engineers, I am saying they come at the products from 2 very different perspectives, MSFS going to XBOX is proof of this. Maybe ASOBO never had that intention only MS, but either way its clear from this. This does not make MSFS any less of a sim, but it does change some things. X-Plane will never see a console (mobile clone maybe) but I think you get what I am saying. LR’s approach whilst great has obviously caused things like graphics etc to suffer, likewise some of ASOBO’s decisions has caused things in MSFS to suffer. Its the way it goes, If they both joined forces we would have one hell of a sim.
I agree that LR/XP was createad with a specific target group in mind and MSFS is targeted at another, more widespread target group, including console players.
However, i dont take this as proof that MSFS is doing anything worse than Xplane or can not be taken as a serious flight simulator. The whole thread here is kind of proof for that. Its just that MSFS is not there YET, where LR is. But they have an advantage by, idk, 10 years or so? Give MSFS atleast another half year and im pretty confident we will atleast match XP, flightmodel-wise.
Take the C172, C152, G36 and maybe DR400 and you will see that MSFS can be an absolute realistic simulator with an awesome flightmodel. Its just not perfect on all the planes, yet, especially the Turboprops.
I’d be interested to see how XP competes going forwards. Asobo is beginning to refine the FM into a nice place. The graphics are unlikely to be matched, or cost a fortune in addons to match. The 3DP environment isn’t as vibrant as MSFS’s already is. Not sure what XP will have as its competitive edge, even though it pains me to say.
So I am reading through this thread and it seems like some knowledgeable posters of aerodynamics have commented in this thread. It seems like the consensus is that either MSFS has a better flight model than X-Plane, or the consensus is that the base of MSFS’s flight model is very good, and with some fine tuning, it can be better than X-Plane’s flight model?
I interpreted it as MSFS has the potential to have more fidelity in the atmospheric model than X-plane due to the higher number of “slices” however X-plane currently has other stuff simulated that MSFS doesn’t have.
I don’t think you can use a simple “which is better” comparison.
Alright, because the X-Plane fan boys keep claiming X-Plane has the better flight model. They have claimed that for a long time. But this thread kind of rips up the notion that X-Plane flight model is better than MSFS’s flight model.
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