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Trebuchet "Mammoth"

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Project by Jim55 posted 11-07-2012 09:24 AM 2071 views 9 times favorited 8 comments Add to Favorites Watch

A home-school project encompassing understanding many things- history, engineering, physics, ballistics and yes, wood working. Also some fun. :)

Our projectiles are typically marbles. They seem to combine the best combination of size and weight. We have broken the 100’ distance a couple times but about 85’ is the norm. Eight pounds is the most weight used.

The string wrappings are functional to help hold things together where the throwing beam is pierced for the trunnion. There were no plans, the design was our own based upon several working examples and largely influenced by “War Wolf” a BBC sponsored attempt to recreate a full sized trebuchet from history.

I believe the design needs improved. The counter weight seems to just drop down with a jerk rather than swinging an arc. I believe the frame needs to be taller and more length of beam from trunnion to counter weight pivot.

There is one neat thing, the engine creaks with rubbing wood making it sound more like a massive machine. I believe the sound is the by-product of some binding in the build. It is held together by toothpick ‘pegs’ and the bindings. Wood is a collection mostly of pine scraps but some pieces of hickory. The counterweight basket is made of that.

Anyway, it was fun building it with the boys and we enjoy ‘shooting’ it. By the way, “Mammoth” is just what we named it and some one day, a considerably larger, say, about a 6’ high frame, is in the works. Should be fun!





8 comments so far

View Monte Pittman's profile

Monte Pittman

14246 posts in 996 days


#1 posted 11-07-2012 11:16 AM

Pretty cool. Looks like fun.

-- Mother Nature created it, I just assemble it.

View Tom Godfrey's profile

Tom Godfrey

466 posts in 834 days


#2 posted 11-07-2012 12:09 PM

Nice. I want to make one of these one of these days. Just to business playing catch up now but maybe later on. You need a great job

-- Tom Godfrey Landrum South Carolina (tom@thcww.com)

View HalDougherty's profile

HalDougherty

1820 posts in 1895 days


#3 posted 11-07-2012 12:19 PM

Great looking siege machine… Lego forts are quaking in fear! Have you seen the 'Punkin' Chunkin' website where they show off modern trebuchet’s. The projectile is an 8 lb punpkin. Google it and build a big machine to compete next year.

http://www.punkinchunkin.com/results/2012

-- Hal, Tennessee http://www.first285.com

View Jim Jakosh's profile

Jim Jakosh

11493 posts in 1764 days


#4 posted 11-07-2012 01:40 PM

Nice looking trebuchet.
The jerky drop may be due to binding in some of the pivots. Maybe opening up the holes for more clearance may make it smoother!!................Jim

Hal, I looked at the records this year and 3800 and something was the best. Didn’t they have one go over 4000 one year?

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View ChrisK's profile

ChrisK

1158 posts in 1740 days


#5 posted 11-07-2012 01:43 PM

Great build. I am almost done with a 6’ foot design for tennis balls and water balloons. My son’s scout pack will use it on our camps to toss water balloons. It should be able to hold 100# of counter weight, though 40 to 50 should be enough for balloons.

Mostly 2X construction, bolted together to help with transport.

Have fun. Try making the sling a little longer.

-- Chris K

View Jim55's profile

Jim55

131 posts in 725 days


#6 posted 11-07-2012 02:54 PM

Punkin Chunkin is a blast! Watching that is loads of fun!

You know, I hadn’t thought of making the sling longer over all. We’ll give that a try. We did add the chain links so we could adjust the trajectory. One link can lower it from a nice low angle shot to a high angle lob.

View Ben Simms's profile

Ben Simms

191 posts in 950 days


#7 posted 11-07-2012 07:07 PM

cool

-- I played with Legos as a kid and I never had the part I thought I needed, so I learned to improvise. Now I'm an engineer with a woodworking hobby.

View exterminate's profile

exterminate

120 posts in 686 days


#8 posted 11-07-2012 08:01 PM

This looks like a fun project. Great job! I’m filing this one away so that one day, I can build one with my boys…..

-- Albert Einstein - "I'd rather be an optimist and a fool than a pessimist and right."

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