I’ve seen turboprops in museums and on the internet with around six or eight blades. When I looked on the Wikipedia page for propfan engines, which seems to be another name for an open turbofan, the distinction seemed to be mainly how the blades were shaped (like propellor blades or turbine blades) and how tightly-integrated everything is (you can swap the propeller out on a turboprop).
How many blades do you have to add to a turboprop before it’s promoted to an open turbofan and touted as a major new innovation?
Trans people have been able to compete at the Olympics since the mid nineties, so if male puberty really did have such a large effect on performance, we’d have had next to no cis women win medals for three decades. Instead, every women’s Olympic medal in that period went to a cis woman. Taking enough hormones to physically change the shape of your body has a detrimental enough effect on athletic performance to wipe out the advantage from male puberty. In principle, an athlete could gain the advantage back by stopping taking HRT, but the Olympic rules require stable hormone levels for two years, so they’d just disqualify themselves if they tried.
There are people who have genuine medical reasons to not take vaccines (e.g. an allergy to a common ingredient) or who are so immunocompromised that a vaccine won’t keep them alive, and they rely on other people getting vaccinated to avoid dying. It’s not just antivaxers who antivaxers kill.
I was meaning that the blade count and detachability was the difference in definition between turboprop and propfan/open turbofan, not that it was necessarily the thing making the engine more efficient.