by RCModelReviews » Sun Aug 07, 2011 11:51 pm
To make a pulsejet quiet you have to convert what is a pulsating gas-flow into a continuous gas-flow. This is a process called integration and is exactly what the muffler on your car or motorbike does.
Unfortunately, integration usually requires the use of large, baffled expansion chambers which are bulky and heavy -- two things that don't go hand in hand with aviation.
I've experimented with running engines 180 degrees out of phase but that only gives about a 6dB reduction in sound level -- hardly enough difference to even detect with the human ear.
RCModelReviews.com, just the facts.