BobbyLucas
Well Known Member
Ok, maybe this is common sense or an instruction I missed somewhere, but as a first-time builder and aviation noob I installed my shiny new 3-blade prop naively trusting that I had received an in-spec set of blades from Sensenich.
When we went to do the dynamic balancing, the baseline reading was 2.2ips. For reference, the Chadwick Helmuth Balancer Manual, https://www.csobeech.com/files/ChadwickBalancerManual.pdf, states "No propeller may be balanced whose initial reading exceeds 1.2 Inches per second velocity."
The balancer pointed precisely at one blade as the culprit. After disassembly, we found that the suspect blade was labeled with a tip weight of 43g while the other two were 32g, an 11g (34%) differential. Sensenich said the spec was <1g differential and most sets ship at <0.5g. They were shocked and apologized profusely.
With no new blades in stock, the only option available to me was to ship the blades back to Sensenich for rebalancing. And of course they would not pay for anything more than UPS ground shipping. But they did throw in a non-aviation related t-shirt for my troubles.
Because of this delay, I lost my test pilot to England for a month.
Moral of the story - had I done this when I received my prop, or at least before installation, I could have taken care of it then, while still working on other things, and not be sitting here twiddling my thumbs in the nice spring sunshine.
When we went to do the dynamic balancing, the baseline reading was 2.2ips. For reference, the Chadwick Helmuth Balancer Manual, https://www.csobeech.com/files/ChadwickBalancerManual.pdf, states "No propeller may be balanced whose initial reading exceeds 1.2 Inches per second velocity."
The balancer pointed precisely at one blade as the culprit. After disassembly, we found that the suspect blade was labeled with a tip weight of 43g while the other two were 32g, an 11g (34%) differential. Sensenich said the spec was <1g differential and most sets ship at <0.5g. They were shocked and apologized profusely.
With no new blades in stock, the only option available to me was to ship the blades back to Sensenich for rebalancing. And of course they would not pay for anything more than UPS ground shipping. But they did throw in a non-aviation related t-shirt for my troubles.
Because of this delay, I lost my test pilot to England for a month.
Moral of the story - had I done this when I received my prop, or at least before installation, I could have taken care of it then, while still working on other things, and not be sitting here twiddling my thumbs in the nice spring sunshine.
