Hi there!
Both in FS20 and FS24, I’ve always had the impression that rain is purely cosmetic and has absolutely no impact on the aircraft’s physics, and if it does, it’s clear that it’s not properly modeled. After a flight I did yesterday, this became even more evident, so this morning I decided to run a few tests.
I used the A330-300RR for this, since it’s the default aircraft that is supposedly the most realistic and best suited for this kind of task. That way, I get cleaner results and no one can argue that the issue comes from a third-party add-on.
For the tests, I used runway 07C at EDDF and conducted several runs in both dry and wet conditions. I kept the same weather conditions for both, with no wind, the only difference being the presence of rain.
To get the most accurate results possible, I conducted both tests in exactly the same way: brakes at the same temperature for both runs, fuel and payload loaded from SimBrief to get the exact same weight, applied TOGA thrust with the parking brake set until stabilized, then released it. I used 160 knots groundspeed in both cases for testing. Once reaching 160 knots, I cut the throttles to idle so that the RTO would activate, and kept the reverses stowed. I ran several tests, and I selected the two best ones to post here, as sometimes the rain wasn’t present over the braking area (I’ll discuss this later).
Dry test:
Wet test:
As you can see, in both tests the aircraft stops almost at the exact same spot, which is completely unrealistic. You might say: “In the wet test, the aircraft stops a bit further,” and yes, according to Google Maps, the distance is 56 meters longer.
But I have an explanation for this:
It’s virtually impossible to make the RTO trigger at the exact same moment in every test. However, by capturing the frame where the RTO activates in both tests, you can see that in the wet test it kicks in slightly later, which matches the slight increase in stopping distance.
Therefore, if the RTO had triggered at exactly the same time, the aircraft would have stopped at virtually the same spot in both tests. And even so, 56 meters of extra distance is ridiculously low under these conditions and nowhere near realistic.
I don’t fly the A330, so I don’t have access to its OPT (if there’s any A330 pilot around who’d like to share real-world figures, it would be very welcome), but let’s compare this with how a 737-800 would behave according to its OPT. I loaded the same runway with the same weather, zero wind, and no reversers, and generated a few examples under different runway conditions (Blue line for reference):
As you can see, the figures from the OPT are very different from what we’re seeing in the simulator. And that’s for a 737. For an A330, the stopping distances should be significantly longer because it’s much larger and has much greater inertia.
The conclusion is that rain and wet surfaces in MSFS are purely cosmetic, just eye candy. Pretty, but with no real simulation behind it. Another thing I believe should be implemented is proper water evaporating behavior. Right now, there’s no simulation at all for it. It’s just: raining = wet runway, not raining = dry runway. The change is instant, the moment it stops raining, the runway immediately dries up. No puddles, no gradual drying, nothing. It’s an instant switch from wet to dry, which honestly completely breaks immersion. In overall, this is an area I’ve confirmed is done better by other simulators.
My request to the development team is to implement this properly, with a real simulation behind it, and not just eye candy. I can’t understand how the team spent so much time refining tire friction, and yet wet surfaces, which would make the most of it, aren’t even simulated.
Thanks for attending my TED Talk.
. That is not the actual Boeing OPT used in real life is it? It can’t be. The runway in your video could be just wet, even in heavy rain, it is usually not more than 3 mm of water which makes it RWYCC 5 (for landing), more than 3 mm becomes RWYCC 2, which I have only seen a handfull of times.