Chaps

What is your experience with ducted/bypassed installations and noise. Assuming a single pipe (ie not bifurcated) would you say they ran any quieter than an 'open' installation??

Cheers
Mark

My bandit (fully ducted by pass) is very quiet compared to similar un ducted models. I beleive this is because the airflow through a ducted model is less turbulent, therefore less noise is created. The bypass also acts as a bit of a noise barrier or attenuator, which is noticeable, especially to the side of the model.

Even gear doors make a noticeable differance to the overall noise of a model.

My UF is extremely quiet with full bypass. Loudest jets I have owned were not. They do make a difference. Generally a bypass will be quieter and faster and the unbypassed will have more static thrust.

The noise heard from plenum installations is called DRAG.