Trebuchet news

[SuburbanFarmer]

Has Okie taken strength of materials yet? This could be fun.

What’s the coefficient for Prayer Power?

[Speaker to Animals]

Well, to begin with, power has no coefficient. It's just work divided by time.

Back to the comments about strengths of materials, what kind of strength? What part are we talking about here?

The arm needs high tensile strength. I think the frame would be different.

[Okeefenokee]

That would combine solids with dynamics. I've taken both separately, but combining them would be cool.

[Montegriffo]

So, basically home brew glulam. Interesting. What kind of glue do you use? What do you use for pressure?

CT1 construction adhesive and G-clamps. Then a box full of screws for good measure.

[Okeefenokee]

None of that sounds period correct.

Are you even using serfs to build this thing?

[SuburbanFarmer]

None of that sounds period correct.

Are you even using serfs to build this thing?

[Hastur]

Serious Trebuchet stuff.

[Hastur]

[Montegriffo]

The Warwolf replica in my sig wasn't allowed to have the ladder going up the frame due to health and safety reg's.
I think I've seen a vid about their original trebuchet, did you post that in another thread somewhere?

[C-Mag]

So, Trebuchet Guevara which we built 2 years ago has been dragged back into the field for repairs.
The frame only needs one rotten beam replacing which is ok considering its been out in the weather for 2 winters.
The throwing arm broke off about a yard from the pivot point leaving plenty of good timber to graft the new arm onto it. This will save us from having to redo all the holes and fittings for the swinging counterweight and the pivot.
I've bought 2 sheets of 3/4" ply which I am going to cut into 6" strips and screw and glue together to make a laminated beam about 4m long.
Last time the arm was too long for the height of the frame which meant it touched the ground before the counterweight was at full height. If I reduce it a little in length I am hoping that I won't lose more power than I gain by cocking it to full height.

There's one week left of the convention.
Watch this space.

How did the plywood go ?
I would be very cautious using plywood in this application. If you thought wood timbers were adversely affected by environmental conditions like water, sun and freeze, you won't be happy with what it does to plywood.

Boats and aircraft have been made very successfully made from plywood, it works. However, having a complete seal on all plywood is critical to maintain at all times.