jsut210
Expert Crash-Lander
Hey guys, My recent project has been converting a Ryobi 31cc wacker engine to put on a SPAD stick. The work on the engine seems to be done, and now I'm tuning all the kinks out of the system. Anyways, I was trying to check what RPM the engine was running at today, and I thought of a smart method. I took a video of it running wide open, then later went on my computer and found out what the frequency of the audio from the engine was. I found this to be about 158Hz. Assuming that the mic picked up a 'bang' for every cycle, or revolution, I then converted Hz to RPM (Hz x 60 = RPM) and got 9480! This seems rather high to me. The posts I've read say that guys are getting 7000-8000 with this engine on a 18x6 prop. So here are my questions:
Is this a reliable method to measure RPM?
Am I going to wear down my engine?
If needed, what can I do to slow it down? Richen?
This measurement seems very strange to me. When I got this engine, it didn't seem to have too much compression. Also, before I even started using it, there was light scoring of the head/sleeve. Thanks for any help.
Also, heres the video:
Click To View
Is this a reliable method to measure RPM?
Am I going to wear down my engine?
If needed, what can I do to slow it down? Richen?
This measurement seems very strange to me. When I got this engine, it didn't seem to have too much compression. Also, before I even started using it, there was light scoring of the head/sleeve. Thanks for any help.
Also, heres the video:
Click To View
