RobRiley, "The benefit of this is the cantilever and so the contributing moment is less, so the whole bearing requirement is less by the difference in mean heights, for example 3ft below deck for a spar and 5ft above for a boss; or 8ft. Among the downsides, the boss is likely to be weighty and the bearings may need an aerodynamic blister on the wing skin to offer sufficient diameter."
Keeping the bending moment as low as possible has to be the first priority, especially the weight of the wing and length of the arm. My calcs are indicating a lift of 2500 kg m/s^2 (32 hp) in 25 knot winds. If the mid spar height (center of effort) is 7 meters, that indicates 18,000 kg's (40,000 lbs) of torque at the base. Which is about 1/4 of the forces on a normal stayed mast. . .
These bearings look interesting and strong enough http://www.kaydonbearings.com/Endurakote_bearings_NG_typeX.htm
Designing and building the male and female spars at the necessary tolerance seems daunting to me though. . . and they seem to create point loads.
On the other hand a metal sleeve against a low friction plastic seems like it would distribute the loads better and be an order of magnitude easier to build and service and cheaper.
The metal sleeve won't rotate quite as easily so I am conflicted.
I am pretty sure plastic against plastic or epoxy or any two soft materials against each other won't work very well, for a variety of reasons.
Talador
__._,_.___
Posted by: taladorwood@yahoo.com.au
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a new topic | • | Messages in this topic (15) |
.