I’m working on a helicopter with a main (top) blade and a tail rotor. When you’re flying, both rotors should be spinning at full speed. They work using HingeConstraints with ActuatorType set to Motor, and blades are welded onto the grey cylinder part that actually spins.
I think the reason the propeller looks to be slowing down is because the rotation of motors is close to the frame rate of your computer.
For example, image that you have a propeller spinning at exactly 5 rotations per second, and you had a camera that recorded at 5 frames per second. every frame that the camera would take would look the same because the propeller would spin right back in its original orientation as the camera was capturing frames, the video the camera produced would look like a still image.
the best thing for you to do is add some sort of blur effect to the propellers as our eyes perceive that as motion anyways.
However that’s definitely not what’s going on in this scenario. I recorded with a high fps specifically to avoid that issue. The footage isn’t great, so I can see why you would come to that conclusion based on what’s available, but you can test it for yourself here and see the issue isn’t FPS-related:I added the solution, so the issue isn’t present anymoreProjectile Testing - Roblox
Try turning a lot while flying. Sometimes the tail rotor will stop completely flat, and take a few seconds to begin speeding up again.