Rain in cokpit desapear at high speeds

[pabletesoy]

Hi,
first of all congratulate ED for the good job he is doing with the rain, it looks better every day.
Although the disappearance of the rain in the cockpit has always happened when you reach a certain speed, I have the feeling that now it disappears when you reach a higher speed than before (with the F5 approx at 450 mml/h). Why does that happen? Is it like that in reality, is it a performance issue...?

[Bob1943]

Agreed, the rain stays visible on the canopy glass at too high an airspeed.  It was not like that in real life (former F-111, F-100, A-37 pilot).

It has been over 50-years since I have been in the cockpit in rainy weather, so hazy memory here, but I seem to remember the rain effect being no longer visible on the canopy glass shortly after brake release on takeoff.  Depending on rain intensity and canopy geometry, it was probably pretty much gone somewhere in the 60 to 90 knots range.  The F-100 had an exterior air blower system to help keep rain off the front windscreen.

It seems like previous versions of the DCS F-5 had it nailed pretty good, i.e., you could get rid of most of it by just increasing your taxi speed.  I have been flying some rainy ILS approaches in the F-16 lately and the canopy rain effect is appearing at way too high an airspeed.  Definitely needs to be dialed back a little.

Try Googling some actual cockpit Go-Pro footage of rainy takeoffs in the F-5, F-16, F-18.  That would be the definitive guide.

Edited Thursday at 12:22 AM by Bob1943

[pabletesoy]

Ahh, I didn't know that happened in the real life. It bothered me that the rain disappeared, I thought it was a bug or something....

[Raven (Elysian Angel)]

When I'm riding my motorbike in the rain, wind blows water drops off my helmet visor as well, so the speed at which that happens certainly isn't that high - particularly when you're talking about aviation speeds...

[Bob1943]

Here you go, some real life footage of an F/A-18 during a rainy carrier launch.  Notice how fast the rain disappears.

The actual movie footage, plus 2 screen captures they posted from the movie.

 

 

Edited Thursday at 11:30 PM by Bob1943

[LoudHoward]

Is there a similar video where it's actually raining though?

[pabletesoy]

Yes, it looks like it's not raining in that video.
Anyway, I love to see the rain in the cockpit even if it's not realistic!

[Bob1943]

Could not find anymore real-life videos with heavy rain at launch.

I just setup a "Heavy Summer Thunderstorm" mission at Nellis in the F-16 and took some screenshots at various speeds on takeoff to have some comparisons as to how fast the rain drop streaks are dissipating.  Here is that sequence from stopped on the runway, to 74-knots, then to 184-knots.  This does not look too bad, it was definitely looking much better at 74-knots which is consistent with my vague memories from over 50-years ago in the F-100.  Still some streaking on the sides of the canopy at 74-knots, which seems reasonable.  The canopy geometry would impact this as well.  My concern was the effect while up in the 300-knot+ range - DCS seems to show a little more canopy rain effect at those speeds than I would have imagined in real life.

Any former F-16 pilots out there that could give some input?