- Sep 17, 2008
That is very nice.One of the guys on the VP group came up with a clever trim idea for the stabilator. It was years ago and I couldn't find his drawing but it looked something like this:
Swap the fixed mounting bracket on the rear face of the stern post for a bellcrank on the front face. Run a bowden cable to a trim control in the cockpit (a vernier or jack screw).
I need to make an accurate drawing to get the geometry right....
View attachment 87269
...a 200 pound guy exerts 200 LBf on a bathroom scale.Can someone talk about this in plain English.
He's just making the point that each eyebolt is rated for 7000 pounds but the max load that will be applied to (and shared by) all 6 eyebolts is only *300 pounds.Evans, in the VP-1 plans and handbook page 63, Stabilator, it says about the flight load on the stabilator that it is at 6.6 g's 300lbs. Like the eyebolts he's referring to in the same paragraph all of the rod ends would need to be magnafluxed. The VP-1 Stabilator is 26" long total and the VP-3 22"
With rod ends the torsion would be forced through the rod ends by the first bell-crank or idler. So that bell-crank or idler would have to be "beefed up" to do that job.
There isn't any way that I understand the loads, no offense taken. I understand the mechanical motion and the geometry. I don't want to end up with an overweight Codwallager, I would like to end up with something simple and more elegant than that. I have sketches, iterations of sketches, and I am still reducing the size and trying to make it simpler so nothing is finished. I will take a picture of a front spar sketch and a rear spar sketch neither are finished ideas just works in progress. Using spherical rod ends I wouldn't try to fix the internal push pull shaft from rotating as shown in the drawing were I was intending to address the rotating motion past the rear spar for example.No offense intended at all but I don't think you fully understand the loads in the control system. Do you have a sketch of your system?
A VP-3 control stick, modifying from cables to push pull tube. To eliminate 3/4" diameter holes in bottom area of both spars. Push pull tube to go thru center of torque tube.I’ve lost track of what you are building and why you want a smaller hole. Can you cover that info again?
Fewer/smaller holes are always better but there's a balance between "ideal" and "practical". You may be going to great lengths (added weight, cost, complication and hassle) to solve a problem that's not really a problem. If Bud Evans was okay with those holes then it's a safe bet those holes are okay.Because less holes in spar center section is better?