Trebuchet

[swamp]

Mods, if this is not the proper area please move.

It is a single shot. Not quite a gun. Got my model of a trebuchet done and had it out for a few test shots. A .600 RB seems to be the best so far. Need to adjust the amount of weight in the box and it should do well.

I will post a pic when I get the finishing touches done.
It is a medieval ball thrower.
swamp

[longbow]

Hah! I built one too but not for mass destruction, mine was for a Cuboree with medieval theme and to toss water balloons. It worked pretty well.

They are interesting devices for sure and the big ones are pretty impressive.

Now you have me thinking about making another to toss 0.735" round balls. What sort of range are you getting with your .600 RB's?

I will look forward to the pictures when you post.

Longbow

[swamp]

So far about 8-10 feet. I think I need to adjust the weight. It is releasing a bit early. Maybe adjust the sling cords. Try one thing at a time.
swamp

[swamp]

Here is a pic. I found out where I touched it with glue on my fingers when I stained it. It is 12 inches tall at highest.

147501

[Ballistics in Scotland]

There is an excellent article by Wilfred Ward in the 1993 Gun Digest, probably cheaply available on sites like www.bookfinder.com (http://www.bookfinder.com), about the trebuchet constructed by one Hew Kennedy on the border of Wales.

His machine was rather on the enormous side, and the use of a sling, with one end slipping off at the end of its travel, increased the range. Its achievements included throwing a 392lb. piano 151 yards, a 550lb. dead pig 171 yards, a 1344lb. dead horse 106 yards, a 112lb. weight 235 yards and a 1680lb. car 80 yards. Clearly pigs have a superior ballistic coefficient to pianos. The missiles were sometimes set alight, which in medieval times, besides its intimidatory and incendiary value, permitted accurate spotting of the point of impact at night. I once hit an owl with the wing mirror of a truck, and the smell was extremely hard to get rid of for quite some time, so a siege could have been made much more unpleasant by bits of decomposing animals. Spies, including living ones, were sometimes returned to their employers by something a lot more distressing than the long walk at Checkpoint Charlie in Berlin. It should be noted that all those ranges are within comfortable longbow range, and even at night operating the thing must have had its dangers.

British society has a firm place for eccentricity which doesn't involve rudeness. Sir Ralph Payne-Galwey (an excellent writer, not in the least likely to be committed, on conventional game shooting) made a lifelong hobby of recreating medieval crossbows and catapults, and his "The Crossbow" of 1904 is well worth reading. He achieved 350 yards with a catapult powered by horsehair skeins, twisted with great force by a ratchet windless, and thought 400 should be possible. That is at least very close to the range at which you could make rude gestures at the medieval longbowman. (Probably not of the large, swivel mounted siege crossbows with which Payne-Gallwey also experimented. He shot a bolt 460 yards with one, which had a 1200lb. draw weight, using the 400 year old original steel bow. but there were always few of those expensive and slow-shooting instruments.) Of course nowadays you would have Kevlar and similar fibres for the skeins. Here is his catapult in the artillery museum at Fort Nelson, near Portsmouth, although the skeins may be more slender replacements.

147503

There is nothing like a good hobby to keep a man out of mischief, and clearly everybody should have one of these. Indeed they can, since in the UK, as it doesn't have a barrel, it is exempt from any legal control. But that was the year they introduced the John Amber Award for articles in "Gun Digest", and Wilfred won, neatly upstaging one of mine. Ah well, you can't have everything. If they weren't bothered that it isn't a gun, why should Castboolits be?

[waksupi]

Years ago at the national rendezvous, a few of us got into building trebuchets. We would use horse apples for projectiles. Direct hits were a real treat!

[longbow]

Mine was about 3' tall and would send a water balloon about 75'. I should have taken a picture of it. It is all now dismantled/dismembered and made into other things.

I used the sling style with a half pipe of PVC for the sling trough/guide. It to get the sling length and hook to release at the right point for maximum distance. Once the "timing" was worked out it was pretty dependable.

Lots of fun!

Longbow

[Idaho Sharpshooter]

Swamp,

we need blueprints, man!!

[swamp]

No prints. It was a kit. I got it from American Science and Surplus. Everything you need to assemble is included. Except the weight.
I did the finishing touches last night. Now to find the right load.
swamp

[swamp]

There are websites that sell kit and blueprints out there. Only limit is how much trouble you what to get into, size wise. I have seen video of VW bugs being tossed.
swamp

[Black Beard]

The one in Fort Nelson was a film prop. I've fired it and it doesn't work properly- the launch angle is too shallow so it only throws things about 30 feet. I think there is a lot of metal inside the wooden exterior. Fine for film though.

[Moonie]

147694
Yankee Siege...

[swamp]

147694
Yankee Siege...

Just the right size for backyard fun.

[oldred]

Man that thing is not out of place here at all, it just goes back a bit further in time than we normally think of when discussing guns! Very interesting indeed!

[swamp]

Alright. I did some range testing this pm. Weight: 3 Lee 1/2lb. ingots tin solder. Tested RBs..350,.490, .600, .610. 350 is way too light. 530 is the one it seems to like best. Got 21 ft and good arch. 490 is second. the heavier two released too soon and very short range. Good thing is I have a lot of 530 RBs cast up. Can't count on recovering the balls all the time.

Now I have to figure out some way of checking accuracy. Lay down a sheet to catch and figure a way to mark where the balls hit. Something not too messy.

More fun than I thought it would be. Maybe set up a Lego Castle to use as a target?

The makers of the kit: Pathfinders Design and Technology. They are in Canada. They do have a website. Maybe more weaponry for the arsenal.

swamp

[Mk42gunner]

Maybe stand up a piece of sheetrock for a target? It doesn't take much to dimple drywall, (at least when I am trying to hang it).

Cheap target and scale model destruction at the same time, sounds like a win-win to me.

Robert

[swamp]

Because inquiring minds want to know. The website is: www.pathfindersdesign.com (http://www.pathfindersdesign.com). They have a lot of interesting kits.

swamp

[dsbock]

I've thought about building one of these for quite a while now. This thread may have finally given me the excuse to get started.

Thanks.

David

[Jeffrey]

There are some interesting items in "Backyard Ballistics" by William Gurstelle. Among which is plans for a catapult. http://www.google.com/imgres?imgurl=http://t3.gstatic.com/images%3Fq%3Dtbn:ANd9GcQVW2PbrTPL7rdkVMM7cVkK0MO-cdhf_K8j5WQSGWOq4-2m8E9p&imgrefurl=http://books.google.com/books/about/Backyard_Ballistics.html?id%3DYipjCgAAQBAJ%26sourc e%3Dkp_cover&h=723&w=508&tbnid=zwTUUNfJenK37M:&tbnh=160&tbnw=112&usg=__Z_bUpSSmRBuEZq6iaIIlP8hc1i4=&docid=DCQXZhqU-E_4mM&itg=1

[Jim_P]

Must be Punkin Chuckin season...

[Moonie]

Must be Punkin Chuckin season...

Almost, wondering who they will get to do it this year, they let all the people that normally did it go from mythbusters...

[Ballistics in Scotland]

The one in Fort Nelson was a film prop. I've fired it and it doesn't work properly- the launch angle is too shallow so it only throws things about 30 feet. I think there is a lot of metal inside the wooden exterior. Fine for film though.

148198148202


Ah, I am sorry if I misinformed you, for the label may have come with the reduced model which undoubtedly comes from the working catapult Payne-Galwey describes making in his book, and with which he achieved the performance described. The one in my last post, though, may derive from a medieval drawing he reproduces and judges to be a pretty good representation of a working catapult - and he is frequently critical of early drawings which got the technicalities wrong. If it didn't work, it would be the nature or size of the skeins rather than the geometry. If these are right, the angle would not be inadequate.

When he made his first catapult Payne-Galwey assumed, as we intuitively would, that the missile would part company with the bowl only when the arm hit the stop, giving only the downward half of a rather miserable trajectory. So he put the main pivot in front of the vertical crosspiece and stop. He found that the range was unsatisfactory, and the arm knocked the crosspiece loose.

He got much better performance when the pivot and skeins were located behind the verticals. Although the tension was so great that three strong men couldn't pull back the arm a quarter-inch (in his rather small catapult) without a windlass, the arm decelerated slightly in its movement, and the missile, which didn't, left the bowl at around 50 degrees. It could be seen in flight before a close-up observer heard the thwack of the arm on the stop. Just the same happened with the pivot in front of the uprights, the difference in performance being because the arm was pulled down through a smaller angle.

He conjectured that an arrow left the string before the latter was straight, but there was no sound to prove it. Good bullet photography existed by the 1890s, but was never applied to the bow. It easily could be nowadays though, with either bow or catapult, using equipment like the Camera Axe:

http://www.cameraaxe.com/

It should noted that in his book of 1904 he doesn't describe the building of a catapult with a sling, as the card says he built in the same year, just a plain cup. He got a range that way of only 350 yards. It is possible that the original makers got better results with human or horse hair, which he considers best for the job. He found that hemp cord had to be oiled, to preserve it and to let it equalize tension on all parts of the skein. He never built any trebuchet but much reduced models, and yet his conjecture on their shorter range is very much in line with Kennedy's results.

To build a catapult you couldn't do better than find Payne-Galwey's "The Crossbow" on www.bookinder.com (http://www.bookinder.com) . But here is an interesting website:

http://www.onager.net/index.htm

There is a warning about safety, basically against building your own unless you know what you are doing, and they aren't kidding. The Romans called the torsional catapult "onager" or wild *** (I only meant a donkey), because it kicked up at the rear end. If it went off prematurely while you were using levers with a proper ratchet, that would be bad enough. But with a bicycle seat and pedals, it could be a ride to remember.

[JHeath]

When I was a young yeoman, I was taught that trebuchet is a tool, not a toy. NEVER point a trebuchet at anything you don't want to besiege.

http://www.bbc.com/news/uk-england-coventry-warwickshire-32264914

"A blaze thought to have been caused by a fireball which was launched from a trebuchet at Warwick Castle has destroyed a historic boathouse.

"Sparks from the projectile are believed to have ignited the blaze.


"About 300 spectators were watching a demonstration of the weapon, described as the 'world's largest working siege machine', when the thatched building caught fire on Friday evening."

[Ballistics in Scotland]

If you can't burn down your own boathouse, whose can you?

[Col4570]

https://www.youtube.com/watch?feature=player_detailpage&v=RN18I-RBVm4
This is a mighty Beast.

[Ballistics in Scotland]

The most interesting thing in that video is that they claim a projectile velocity of 150mph, and yet the tip of the limb moves at nothing like that speed. That would be the effect of the sling. The trebuchet really came into its own with heavier missiles. With the 15kg. mentioned, catapults powered by twisted skeins would get longer range with a smaller instrument.

[Col4570]

https://www.youtube.com/watch?feature=player_detailpage&v=Oq6Hc6xYFSA

Fascinating views of Trebuchet in action.