A bunch of years ago when we used to fly the 60 2 strokes, I used teflon couplers for a little while because they were free and easy to come by--I worked for company where I made the stuff for high pressure hose applications. The 2 strokes of the day would typically turn in the 10k-11k rpm range and my models tended to be more noisy than others. Then one day I was running the engine up and was looking at various spots in the model to see if a specific source could be isolated. Surprise surprise, I found that when I would touch the teflon coupler with a sili rubber pad, the noise would dissipate considerably and it would come back when the pad was removed.
I reasoned that the plastic is just too firm to attenuate the noise at 10K rpm, so I grudgingly went back to sili rubber and the noise was significantly reduced. It's been so long ago when I did this experiment, I had forgotten it
Matt
ORIGINAL: MTK
Peter are you using a teflon coupler in the YS 4 cycle?
Matt
ORIGINAL: PeterP
James,
I am currently flying the Alliance with exactly the same equipment as you. I found a lot of noise is coming from my pipe coupler which is slightly loose. I am looking at other options at the moment. When I apply a little teflon tape around these fittings to make things tight again the model suddenly goes silent again . A flight or 2 later as the tape wears away the noise comes back.
Peter