Yeah, there's a stop on the slide. In addition I have a wire link made from coat hanger that restrains the "drawer" when I'm just running the motor up for tuning etc. and I replace that wire with the fish scale when I want to take thrust data.

That exhaust stinger is an old "Clark" Irish tin whistle. It already had the holes in it so I just cut a hole in the stock muffler and stuffed the end of the whistle in and brazed it up. It works great and it's pretty quiet.

I thought I was done with the reed mods but I just couldn't resist taking it one more step further. I measured the force to open the reed to the stop (set to 1/8 inch) for three different configurations.

120 grams for stock reed and clamp
52 grams for contoured reed and clamp bent so that only the mount end of the reed contacts the clamp
30 grams for a reed with a bean hole cut in it to reduce the "spring" area.

I chose to cut a bean shaped hole in the reed as apposed to a waist, the argument being that with the wider links it would provide better stability than with the waist configuration with only a central link. I hope it holds together. A broken reed floating around in the crankcase even for a few revolutions might not be too good!

Of course all this reed work is arm chair engineering at it's best. One could make a whole project out of the reed design for the Ryobi. When the engine is running the reed is probably vibrating at the frequency of the motor speed and who knows what the inertial response of the reed is and whether reducing the spring force or the mass of the reed will help it or make it worse. The response of the reed depends on both the spring force and the inertia of the reed of course. I'll run it up tomorrow and see if there is any change.

Sorry once again for the out of focus photo. My camera doesn't do close focus well.

diceco

BTW: There is no indication that the reed has ever hit the stop on any of the engines I've seen.