Hey Rog,

Most helis don't have a filter anyhow. It's only for the really dusty places where the collective kicks up all the dust. If you do decide to use the sponge, make real sure that it's clean, and soak it with air filter oil or some fuel to help catch the dust!

Also, your clutch is too tight. The rotor should be engaging a little farther than idle. Adjust it somehow so the spring is softer, and the clutch shoes have more weight, or less counterweight material.