SU1 Beta Helicopter ground effect is still wrong

[MartnMacRae]

ISSUE DESCRIPTION

Description of the issue:
Helicopter ground effect is improved but still not right! Main problem: the entire airflow in ground proximity is based on the relation of rotor disc to the nearest object underneath it in terms of height.

Or in more detail:
Firstly, when on an elevated helipad hovering in ground effect (HIGE) and slowly moving to the edge and beyond it, there is no asymmetric lift. Let’s assume forward movement, what should happen is less lift on the front of the rotor disc the more it goes outside of the pad. This leads to downward pitch while also decreasing height above ground gradually, if not compensated. This is of course dangerous flying practice, because the tail would strike the pad. I tested it just to see what the algorithm would do. It seems the algorithm instead doesn’t change the ground effect until all of the aircraft or at least the rotor disc is away from the pad and -then- recognizes the HOGE situation and induces a !symmetric! decent. I checked the CFD, on the front that goes over the edge it displays air hitting an invisible ground. Only when the entire downwash is off the pad, the airflow changes.

Secondly, when approaching the mini-helipads on the agriculture trucks the yaw disturbance is gone (although I feel not 100%, some weird movements still persited) but since the ground effect is recognized wrong, as described above, approaching it leads to a change where the truck is interpreted as the “new ground level” just like with going over the edge of helipads above but the other way around! The rotor disc “sees” the truck and sets the ground effect for the entire disc to the elevation of the truck.

This nonsense in two ways: the ground effect shouldn’t be applied 100% if only parts of the rotor area have a higher object below and for objects smaller than the rotor, in case of the spray truck about the width of the helicopter fuselage, the downwash would stream around the object to a “loose end” if high above ground, or hitting the ground on same level as the airflow from the rest of the disc.

What is now obvious is that the MSFS helicopter downwash simulation at the moment cannot deal with the topology beneath the disc. It recognizes the nearest peak normal to the disc and seems to interpret it as an unobstructed, wide open flat surface and applies the ground effect to that.

One might call this a limitation of the flight model. I still call it a bug, because you made the pads on those spray trucks so small (with terrible collision detection) and that makes it a problem, because it makes landing on them way harder than it should be!

If applicable, which aircraft is experiencing this issue:
Tested on H125 in free flight and career mode

[PC Only] Did you remove all your community mods/add-ons? If yes, are you still experiencing the issue?
No relevant addons were active. My folder mainly contains 3rd party aircraft.

FREQUENCY OF ISSUE

Tested twice. Problems are of integral kind, basic flight modeling. Occurs every flight.

REPRODUCTION STEPS

1. Start flight with the H125 and approach an elevated helipad
2. Hover 0,5-1m above ground and slowly move towards the edge of the pad
3. Maintain this attitude, no change on the collective
4. Notice there is no effect when the rotor disc is half way off the pad
5. Notice decend once the disc has cleared the pad completely

Or better:

1. Hire a helicopter pilot
2. Have him test your physics before release
3. Take him seriously

YOUR SETTINGS

What peripherals are you using, if relevant:
Virpil Stick and Collective, Winwing Pedals

[PC Only] Are you using Developer Mode or have you made any changes to it?
No

[PC, MSFS 2020 Only] Are you using DX11 or DX12?
Not relevant

[PC Only] What GPU (Graphics Card) do you use?
4070 Ti

[PC Only] What other relevant PC specs can you share?
R7 5800X system, 64Gb RAM

MEDIA

MSFS 2024 SU1 Beta Ground Effect

[END OF FIRST USER REPORT]

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For anyone who wants to contribute on this issue, Click on the button below to use this template:

Do you have the same issue if you follow the OP’s steps to reproduce it?
•

Provide extra information to complete the original description of the issue:
•

If relevant, provide additional screenshots/video:
•

[SmotheryVase665]

Moved from Bug Reporting Hub to Sim Update 1 Beta | MSFS 2024 .
All SU1 Beta bugs should be reported in the appropriate Sim Update 1 Beta | MSFS 2024 category
Thanks!

[pvaiko1203]

I’m also wondering, how strong the ground effect change would even be in case of the spray truck. That landing pad is probably 3x2 meters, the whole truck is maybe 2.5x8 or so, we are talking about 6-20 m2, while the rotor disc area of the H125 is about 90 m2. Less than a quarter.

[c0d3c2004]

I feel your pain. I gave up flying the helis, it’s not worth it.

The fact that it was sooo wrong at release beggars belief and I don’t expect something so fundamentally wrong will be fixed in a hurry. I would love to be proven wrong.

[MartnMacRae]

Exactly my point. Especially when hovering right above the pad the „shadow“ of the fuselage reduces the effective obstruction. In my view in this case there are just about no features on the truck that would enable a GE cushion to develop. There would be some vortices, but I think most of the air flow just bends around the truck, which makes it a situation just out of ground effect.

Flight models have limits, this has to be accepted… but in this case it teaches a wrong lesson, as the helicopter “sees” the pad as soon as the rotor disc overlaps it and just steps up the entire ground level. After which the flight model increases height above ground to adjust to the power settings that haven’t changed.

Writing you about it, one idea would be to have the ground effect fractioned by the relation between rotor area and surface area the algorithm recognizes as a feature the ground effect has to be applied to. It would be no simulation of the aerodynamics just a workaround, but it would reduce the too high lift.

I recall Belatu42, a real life R44 pilot and youtuber, saying that you do feel reaching an elevated pad and have to adjust a little.

But what MSFS does is just wrong.
And it makes something they intend the player or simulator pilot, as you like, to do harder than it should be.

[MartnMacRae]

Same here. My consequence was to go back to MSFS 2020 and XPlane 12 and some DCS Huey flying. With the Beta SU1 at least the standard landing is not rewarded with a sudden slap in yaw that completely ruins the experience

Don’t give up on helicopters! All it takes is some 3rd party dev to show how it’s done and then MSFS 2024 really would be worthwhile

[Zibus30]

@MartnMacRae

Or better:

1. Hire a helicopter pilot
2. Have him test your physics before release
3. Take him seriously

totally true ! The fact making land an H-125 on a truck is a huge nonsense first of all… And when you try to do that it’s as if a giant gave you a big kick in the butt when you’re close to the “pad” .

[pvaiko1203]

I think in 2020, after SU15 it worked much better, I can’t remember such a noticeable GE over a truck or the small logging pads, I’ll test it tonight.

When you look at helicopters crop dusting on YouTube, they always leave the truck practically horizontally which probably wouldn’t be a good practice if there was any significant GE.

Incredible Helicopter skills 2016 | crop dusting in Kentucky New

[pops738]

I sincerely think that some of you either don’t know how to drive or don’t know how to go into beta, I tested the R66 and the h125 on a spraying mission and it works very well, no problem landing on the truck, I tested the h145 on a 10th oil platform and no problem either, in SU1 it works very well!

example https://youtu.be/iaW8SJ2e6L0?si=faHW9QKw7oM8b_WY

[nierga8]

I’m still not able to finish an agricultural mission with the R66 due to the parking brake bug.
Is there a workaround to activate the ghost parking brake?

[Chewwy94]

Thank you for the bug report.

We have created an internal ticket to see if our team already has this logged, and if not they will attempt to reproduce the issue and create a new bug report. This item is now marked as feedback-logged. If there is an existing bug report or one is created, we will move this thread to bug-logged.

[pvaiko1203]

Wow. Someone is very confident here. You should probably scale back a bit and try to discuss this topic without denigrating others.

No one said they haven’t fixed the big kick in SU1. Yes, that, and the yaw is gone.

However, there’s still a subtle push when flying slowly, level towards the truck, and you can see the reason perfectly in the screenshots of the first post.

On the oil rig platform however, we do expect to feel the ground effect as it is much bigger than the rotor diameter.

[MrtnMrc1948]

Now without smashing it and on the chemical truck. Thanks!

[MartnMacRae]

Thank you all for taking time to read my post and reply on it. I very much appreciate it!

To the response: There actually is a good point in there. Why did I post the topic? Several reasons: I enjoy the whole MSFS experience. It gave me many hours of flight simming fun in the far past (4.0 to FSX) and even more so since 2021. So I am rooting for it to overtake Xplane in terms of flight modeling and being the benchmark. MSFS has way better immersion and potential. In XPlane 12 or older you have to puzzle a playground together with the right aircraft and the right scenery and some other extras. And then it still looks like 2010 if even that. But while Xplane has a keen eye on it’s physics and dev environment, MSFS since ever was aimed more to the casual market IMHO, so as-good-as-possible physics tended not to be the top priority and neither a good dev environment to add what is missing. But since MSFS 2020 forums such as this are common and devs are really listening. This encouraged me to join in. Also the fact that a lot of 3rd party devs did awesome jobs on 2020.

Why this issue: because on the one hand I have a technical background and discovering that some simulated air stream hits invisible ground goes against my engineering OCD, and on the other, now seriously, MSFS 2024 was supposed to be a step forward and on choppers we got that yaw bug and other things like autorotation functionality, rotor rpm dynamics, VRS and flight modeling at high speeds that are still iffy compared to what Xplane and DCS can do.
When the beta came out people on YouTube started posting “Helicopter issues are now fixed” (period) and this is not true in my opinion. So I used this forum to at least leave my findings and opinions of where we are at atm.

Your comment is in the same vein. What do you refer to when you say “it works very well”? The flight model as a whole? The yaw bug that has been rectified in the beta? (which hints that I managed to install the beta so that leaves me being a worse pilot, you got me ) If one doesn’t care about these things I mentioned that is all well and good, but if those that care don’t give feedback, I fully understand if the MSFS devs keep it a low priority or drop refinement. I imagine we are pretty niche already here.

Another aspect is that the general state of career mode and the fact I sat through all the license tests and according first missions made me sensitive about the gameplay. I still don’t get how the yaw bug made it into the release version if the gameplay developers intended the player to land on that truck.

So, ground behavior didn’t function right on the release version, the SU1 is now beta, and the point of a beta is to give feedback. The improvements are recognized and I found something that doesn’t reflect reality, at least what the CFD overlay shows and what happens to the helicopter. So I posted about it. I can upload the video recording as well if that helps. The resolve can be many things, including me being wrong about stuff. I am just trying to participate to make something great even better.

Thinking about this, I realize that I should scale back my sarcasm towards MS/Asobo. Playing through career mode and experiencing all the bugs just was so frustrating, but SU1 beta showcases the will to improve. I think that’s great.

What is not helping anyone though are round-house kicks about insufficient skill while only bringing to the table that for you all is solved. It’s also very interesting that this same kind of discussion can be found on many other MSFS topics including people (rightly) complaining about general stability and connection issues with according to them sufficient connection specs that are being yelled at by other users that don’t have issues Why do that?

[MartnMacRae]

Are you on SU1 beta? Saves me an entire spray mission to find out if it is still there
As for the release version + hotfixes I am not aware the bug was fixed and neither any workaround. But I on this issue I am sure it will easily be fixed

[nierga8]

Yes, I’m in the beta. I too think it’s an easy fix, but also I see other issues having higher priority on the list. So who knows when it’ll be updated.
After seeing minor fixes in other aircraft recently, I hoped this would’ve been fixed too.
At least crop dusting missions for helis aren’t that long. I’ll keep trying every now and then in case they drop a server-side update without notice.

[pvaiko1203]

Do you have the same issue if you follow the OP’s steps to reproduce it?
• Yes

Provide extra information to complete the original description of the issue:
• Tried helipad 11 of the Heli Forester scenery (https://flightsim.to/file/67641/heli-forester), both in 2020 and 2024. First used the H145, the very same aircraft. When approaching the logging helipad from the front, flying level, almost at the level of the pad, there is an upward push when the RA jumps from about 15 to 3 ft. The push feels stronger in 2024, but it just puts me a 1-2 feet higher and easy to compensate for. Still don’t think it is realistic.

Trying the same pad with the H125, the push with this aircraft is also sudden when going over the edge, much stronger, lifting the aircraft up a few meters. So definitely there are differences due to the flight model as well.

Also, with the H125 you can easily “climb” a hill, just approach the hillside slowly, it will lift you up, and if you keep a little forward movement you’ll be able to climb any hill without ever adding collective. Haven’t tried this with the H145.

If relevant, provide additional screenshots/video:
•

[MartnMacRae]

Thanks!

I made a video, here https://www.youtube.com/watch?v=IipZY1UBrCU

Pops inspired me to check out the oil rig and there are weird effects happening there as well. At the end of the video I added a comparison to Xplane 12. There the helicopter drops gradually in altitude the more you leave the pad and rises to a height above pad according to the power setting but only if enough of the rotor disc is already over the pad. This seems logical to me…

[pvaiko1203]

Thanks for these videos, they very clearly show that the CFD is implemented to work over a single plane, and it seems to ignore any difference in altitude across the rotor diameter, like here, over 80% of the rotor disc area is off the platform, but CFD still shows airflow deflected by the (non existing) surface:

Would be interesting to see if the CFD behaves the same in 2020.

[MrtnMrc1948]

Thanks for the vids, they show perfectly the issue.

Asobo, please fix it.