ORIGINAL: MTK
Today was a real sanity check for the SAP. It was referencing against glow engines (1 2 stroke and 1 4 stroke...the other 7 or 8 were electric). I went to the first contest with this comination...SAP/ES30G turning a cut down wood carbon hybrid prop. I didn't try the 17x12.....
Bottom line, engine and the cut down version of this prop was noisier than I had observed in earlier runs. My set-up is not quite where I want yet.
The dominant noise maker sounded like the flapper intake valve to me. Curious to know if a rubber lining on this valve could reduce the noise. I will discuss this with Todd as soon as I have the opportunity.
Nevertheless, the sound of the SAP gas engine was totally unique out there...completely different than anything else flying
Another interesting tidbit on noise....yesterday I flew the system over trees and grass and the suppressed sound came back. Could still hear the flapper valve but the noise was back to where it had been.
Comparing that to what it sounded like at the Jackson contest, there was no comparison. The Jackson field is located in the middle of a sand basin. Ed thought that sound reflection and maybe even resonance off the sand was a significant contributor to the loudness at the contest. He probably has something there