I took BV-155 to a test flight and i was able to climb to some 17.2 km in it. And it’s pretty awesome step climber, too. Struggles above 17.0 km somewhat, but surely can fly level at least few hundreds meters higher than 17.2 km, in a proper attempt. Indeed, it should be the highest alt prop, then?
Maybe not! %)
Just about when i was to start trying to make a definite altitude record-holding flight, i took a look at everything i got “one last time” to make sure i ain’t missing anything, and i found another contender! It easily managed level flight at 17010 m before running out of fuel, DRAMATICALLY exceeding its stat card’s max altitude.
So, it seems there is one little hidden “17 km club” for props, huh. With at least two members - BV-155 and that other prop i found. I wonder if there’s any other prop which belongs to it, then?
And, knowing that lots of people will doubt that any other (than BV-155) prop can go 17+ km, i just uploaded a video of it to WT main sub. As you can see in the video, the cockpit is definitely not BV-155’s cockpit. I wonder if anyone would recognise this aircraft by its cockpit, or any other features. This video - is here: 17010 m - reddit video.
I will investigate further, taking both this new contender and BV-155 to longer high-alt runs. Most likely, i will create and present a video presenting the highest i can climb, but it will take time (at least several days). So for now, i’m still looking for more “17 km club” contenders. Any contestants? :).
P.S. Sadly, good old Ta-152 H-1 thus falls behind, and won’t be crowned the highest-altitude prop of the game. Sigh. Also, that other prop i mentioned before, which i was able to get to 16105 m - also failed to reach 17 km. I tried proper hard for it, but it just can’t get above 16.5 km.
P.P.S. TIL: historically, in real life, October 1938, Caproni Ca.161 managed to climb to 17330 m. And this is STILL STANDING world record for crewed, manned BIPLANE altitude record. WOW!

