pajobubo wrote:In a simple boomilever, where the piece in compression is perpendicular to the testing jig, isn’t the force of compression on the compression piece twice that of the force downward applied by the bucket? So 30kg at full load?
Also for the tension pieces would you guys normally make those out of dense balsa or basswood or regular balsa... what affects the strength of wood under tension?
I believe the compressive force (as well as the tensile force) will be determined by the angle between the 2 members and the load imposed.
Think of the extreme case. If you had a boom with compression beams extending to a wall, and tension chords at 89 degrees to it, connect to... lets say a cloud, there would be very little compression force. nearly all of the load will transfer at nearly 100% to the tension rod.
Now think of the opposite extreme... Compression beam back to the wall, but the tension cord is now a cable set at 5 degrees to the beam, anchored to the wall and around a pulley at the end of the beam then continuing down to the load. You will have immense pressure on both the compression beam and the cable.