RealFlight 7.5 (and the newer Evolution versions) uses a proprietary InterLink controller or a specific USB dongle for copy protection.

While it might be tempting to look for a to save a few bucks, going that route usually causes more headaches than it's worth. From "bricked" controllers to malware, the risks are high.

A great free sim provided by Multiplex that uses high-quality German engineering for its flight models.

If budget is the issue, there is a cheaper "Trainer Edition" that gives you the core physics and basic planes to learn on without the full price tag [6]. Top Free & Legal RC Simulators

If you want a free experience that is legitimately than a buggy crack, try these:

RealFlight Evolution supports VR headsets, providing an immersion level that version 7.5 simply can't match [5].

Instead of struggling with outdated, pirated software, (the current standard) is the superior choice for a few reasons:

If you are into racing drones, this is a free, polished sim available on Steam.