The did a quick hand layup of the rib yesterday using some carbon and basalt. It ended up weighing 178g and should be tough enough to stand on. I couldn't get any deflection by pressing on it in the middle, supporting one end on the bench. I didn't try really hard as this wouldn't be a good test as once its bonded in the shell, the shell will add more stiffness. Another reason I didn't try too hard is that the rib was not even close to fully cured.
I glued the rib in and could check out it's effectiveness today. First I put the part on the floor on some foam and stood on it. Definitely strong enough. Then I supported it on some blocks on either end and stood on the middle and jumped around carefully. My conclusion is that it is a bit overbuilt. It took about 50g to bond in so ultimately with a bit better layup using vaccum, just slightly less material the finished weight bonded in could under 200g. Now just to make at plug and mould so I can do one for the other side. Looking down on it from above.
I like this idea even though I don't know much about Velos. It has been fun watching you document the steps of how you are making the Milan.
ReplyDeleteWhat method is used to join the left and right halves of the lower tub section together?
ReplyDeleteLooking very good so far. Keep up the nice work.
First I abraid the surfaces where the seam goes really well. Then the parts are taped together on the outside with plactic tape. On the inside I laminated a beefy amount of glass in the chain trough. This adds stiffness to the shell. I could have lightened up the seam ahead and behind the chain trough as it doesn't have to be as strong in the ends. Using some Kevlar and carbon to make the join makes great sense. Thougher and lighter. Weight saving of at least 150g. With the next one I may clamp the two moulds together and try putting the parts back in the mould after trimming. This may be a better way of aligning the parts.
ReplyDeleteThank you for that very clear answer.
ReplyDeleteWhy is it that the lower tub is produced as 2 separate pieces in the first place. This is a different practice than most other velomobiles?