# What is the rotor speed of an EC135/H135 helicopter?

I need the Eurocopter EC135's rotor speed to estimate its natural frequencies. I checked the helicopter TCDS but I only find there percentage values. For example for the P1 variant: 104% Max and 95% Min. This is percentage of what? In other helicopters I normally get concrete values in RPM.

## 2 Answers

The main rotor speed (100%) of the EC-135 is 395 RPM.

• Thanks a lot. Interesting that the Wikipedia in german as it and in english doesn't. I had already stated this situation before. – Cardeira Dec 13 '16 at 12:17

I don't have an exact answer for the EC135, but in most helis, its somewhere arond 400RPM. Remember that the tips of the rotors cannot go supersonic, so its dependent on rotor diameter