Blain
Well Known Member
RV-8, Sensenich FP, Vans spinner. Quick search doesn't return any recent threads on the topic.
Vans says use a 2" diameter washer under bolt head and trim them to clear spinner bulkhead. I have a set of these from another builder. It just doesn't seem like the thing to do. An email to Sensenich got me "Do what Vans recommends".
The only reason I can see to use this size washer is for the increased clamping area on the forward bulkhead.
As usual I may be over thinking it but I find a couple of drawbacks to this.
The trimmed washer will still turn when applying final torque until it hits the step in the spinner. Seems like that will create a stress zone.
Another issue which is probably easy to cure is the imbalance between the weight of the trimmed washers. I found 0.1 OZ difference. Even though they have a short arm to the center of rotation it must contribute to a harmonic imbalance.
Then the stack weighs 7.4 OZ, standard diameter washers only 1.8 OZ. that is rotating mass about as far forward as you can get.
I've learned over the coarse of this build what looks improper usually has a reason. Am I missing something?
Vans says use a 2" diameter washer under bolt head and trim them to clear spinner bulkhead. I have a set of these from another builder. It just doesn't seem like the thing to do. An email to Sensenich got me "Do what Vans recommends".
The only reason I can see to use this size washer is for the increased clamping area on the forward bulkhead.
As usual I may be over thinking it but I find a couple of drawbacks to this.
The trimmed washer will still turn when applying final torque until it hits the step in the spinner. Seems like that will create a stress zone.
Another issue which is probably easy to cure is the imbalance between the weight of the trimmed washers. I found 0.1 OZ difference. Even though they have a short arm to the center of rotation it must contribute to a harmonic imbalance.
Then the stack weighs 7.4 OZ, standard diameter washers only 1.8 OZ. that is rotating mass about as far forward as you can get.
I've learned over the coarse of this build what looks improper usually has a reason. Am I missing something?