HingeConstraint for Plane Propellor is Stuttering

I’m setting up a plane model that was given to me a while back, so that the propellors will spin, giving the plane a nice effect while flying. The entire model is made up out of numerous mesh/3D model parts.

I set up one of the propellors, and this is what is happening:

After some time (maybe 30-60 seconds or so), the propellors seem to smooth themselves out, as seen here, and have far less stuttering, but it’s still somewhat noticeable to me.

Here’s the setup for the HingeConstraint that joins the propellor part(s) to the main part, as well as the properties of said HingeConstraint.

As you can see, the plane has a fair amount of noticeable “stuttering” where the propellor goes really fast, slows down, and then speeds back up again.

I’ve set up a few other 3D models/mesh parts to have propellor spinning too, and I’ve had no issue with them, as seen here and here; they run very smoothly!

Am I overthinking this, especially if the HingeConstraint stuttering seems to diminish a lot after some time? I still think it is fairly noticeable.

Or is there some way to fix this issue?

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Sooo, 300 radians per second as your AngularVelocity is a little high. That converts to 17188.7 degrees per second, which equates to over 1 million revolutions per minute!
Set it much lower. I’d decrease it to something like 10 to see how that looks.

Remember that Roblox games render at 30 frames per second normally. So in the case of 10 radians per second that’s 573 degrees per second. Divide that by 30 and you get a “picture” (rendered stop action frame) every 19 degrees. That’s what creates the stuttering image.

It’s just like if you see a video of a real airplane propeller shot at 30 or 60 frames per second you can see the propeller seem to stop rotating when the degrees per second is evenly divided by 60. A 3 bladed prop turning 120 degrees per second would seem to be stopped, and same at every multiple of that number.

Another way of hiding this issue is to just remove the prop entirely after the engine is turning and put a flattened, black cylinder that’s semi-transparent in place of the prop. When you look at a prop IRL that’s pretty much what you see anyway. I’ve done the same thing with a decal too, it’s black in the center and has a yellow ring at the outer edge where my yellow prop tips are.


Yeah, that fixed it. Which was odd, since the smaller propellors shown in the other GIFs I posted also had a relatively high spin rate.

Thank you!

The mass of the smaller props may have helped with that. From what I understand HingeConstraints are pretty ‘flexible’, so if you use them for vehicle steering they may bounce around, even with the forces set really high.

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