The sound of a low deep frequency rapid pulsing to a dead stop above us. Then silence. 5 seconds later loud accelerating pulses and

My 5 friends and I were out camping off NF70 in Greenwater WA. It was around 4pm. We were all around the campfire when we heard this incredibly loud deep low pulsing noise in the sky come to a stop above us. My friends dog started growling with her cakles up for no reason. We all looked up and saw nothing. It went completely silent. We looked at each other with extreme confusion. 5 seconds later the pulsing started and sped up in pulse speed and you could hear it take off per say. The sound was something like you hear from the star wars pod racing. The deep pulses you could feel in your chest. We all stood there a bit freaked out and confirmed we all just heard and felt the same thing. It's a noise none of us had ever heard before. This was an experience we will never forget.