waterboy2110
Well Known Member
Finally got around to making the fixtures and testing out the DynaVib prop balance tool. Pretty impressed with the results.
There was a point when you pulled the throttle out a vibration would set up and resonate. We went through everything from mounts to carb balance. My buddy was still thinking he could tune it out but I pretty much knew that wasn't it.
I put the DynaVib on and measured in the high 0.6's at 360 degrees and began adding weight. When it was all said and done there's 29 grams split between 180 and 170 degrees. Final numbers are 0.01 IPS for three consecutive runs that randomly clock the prop, basically just noise.
It's a noticeable difference. The only vibration now is the pulse of the engine and the shudder while decelerating is gone. it's most notable during idle once warmed up.
An interesting aspect of this testing was that as the engine warms up the pulse clocks around the hub. I wasn't expecting this but it's consistent over the course of a couple days of testing. I assume that as the gears and everything forward of the gear box warm up they settle in to a place they like to be.
If you're flying a Rotax and just want to know what you're IPS is I'd be happy to come by and set it up any where between say KFAT and KRDD. Five minutes after the cowl is removed and the engine is warm and you'll have the data. Just an opportunity to meet folks and use the tool for me.
There was a point when you pulled the throttle out a vibration would set up and resonate. We went through everything from mounts to carb balance. My buddy was still thinking he could tune it out but I pretty much knew that wasn't it.
I put the DynaVib on and measured in the high 0.6's at 360 degrees and began adding weight. When it was all said and done there's 29 grams split between 180 and 170 degrees. Final numbers are 0.01 IPS for three consecutive runs that randomly clock the prop, basically just noise.
It's a noticeable difference. The only vibration now is the pulse of the engine and the shudder while decelerating is gone. it's most notable during idle once warmed up.
An interesting aspect of this testing was that as the engine warms up the pulse clocks around the hub. I wasn't expecting this but it's consistent over the course of a couple days of testing. I assume that as the gears and everything forward of the gear box warm up they settle in to a place they like to be.
If you're flying a Rotax and just want to know what you're IPS is I'd be happy to come by and set it up any where between say KFAT and KRDD. Five minutes after the cowl is removed and the engine is warm and you'll have the data. Just an opportunity to meet folks and use the tool for me.