120 lb. Counterweight Baseball MURLIN
Vložit
- čas přidán 12. 09. 2024
- All the bugs are now pretty much worked out. Adding a release at the top of the frame eliminated the cord bounce which plagued earlier attempts.
Plans are available tucsonpumpkintoss.org. You can still reach me with questions at murlintrebs@gmail.com.
This is moderately challenging to build, and should not be your first woodworking project without help.
PS: The Syrian rebels appear to have built their own version. See • Syrian Catapault
That ball releasing from the sling and seeing it put that spin on the ball is amazing
Love the video. Good to see MURLIN up and hurling again.
MURLIN IS THE BEST
Try a 4-seam release. It should give a little more Magnus effect. And give a "pure" unisling a shot.
@OldFatSlowGuy44 :
If you're right about the 3rd arm being the place where the projectile leaves the cradle, then there isn't any reason I can think of that the 5th arm should be smaller than the 4th. I might want to look into that.
On your second thought, not having a sling means leaving a lot of energy in the main arm at release. The whole efficiency technique of atrebuchet is based upon the sling 'harvesting' the energy from the main arm before release, bringing it to a stop.
LV
Tedd: Motion transfer would be related to the distance from the CG as well as relative velocity, as centripital acceleration has a role to play as well. The overall idea of a trebuchet is to get everything motionless at the bottom of the throw except for the projectile just as it releases.
I use 5 cams instead of continuous to reduce throwing arm inertia, which is an important limitation of how much CW mass you can drop with any real efficiency.
LV
when filming in slow motion don't change the camera position while the event is occurring instead show it multiple times from different camera positions.
Tedd:
I distribute the baseball treb plans (non dynamically tuned) assuming folks are comfortable with the following two conditions.
1) You cannot distribute the plans to anyone else without my permission as the material is copyrighted
2) You continue to give me feedback about the plans so I can improve them.
Assuming you're OK, with that, send me your email address and I will send you the design package.
LD Vance
Nice looking machine! Great job!
Seems to me that an aluminum throwing arm and steel frame would work marvelously. I wish I had a metal shop to try it myself
This trebuchet design -- and this CZcams video -- has now seen ACTUAL USE ON THE BATTLEFIELD in the Syrian civil war in Damascus. For real. Probably the first time a trebuchet has been used on the battlefield in close to 700 years. See photo #9 in The Atlantic posted profile "DIY Weapons of the Syrian Rebels". (Google it). No, I'm not kidding -- this is deadly serious and it's FOR KEEPS.
So now that you pretty much finished that Merlin is there another catapult in the works to throw a bigger item or are you still going to use that merlin to throw a 1000ft
@ACDC5968 : it's the high speed camera zoomed in. got lucky and caught it the first time. It looks like the ball is spinning mostly about the axis of flight though, which explains why there isn't much magnus lift (I think). I need to figure out a way to keep the sling from reorienting before release.
Hey, I live in Tucson and have never swung a hockey stick. Unless it's as strong as 1x2 red oak, I'm not sure I'd do it that way. Of course, you could use less CW and get away with it anyways.
I can easily fabricate the frame of this machine in steel. Both lightweight round tubes and 2x3" structural box-tubes. I think it would be interesting to test both a wood and a steel rotating mass as well. Plans have already been requested per your listed email address and conditions. Thanks.
@Scrappingt0nVI : Actually I haven't yet given out any copies of the dynamic tuned version. I may eventually may sell them for a very nominal price, though there isn't any chance of that in the short term (since I don't have soft copies of the plans yet). You can get most of the performance from the non-DT version. Are you interested in that?
LDVance
I got my little F2K chunkin base balls 800' with 102 lb. It was pretty scarry loading that much cw for the first time.
I love that song I have it on my iPod sweet machine I am thinking of building one. I had a question about throwing arm is it a good idea or a bad idea to use a hockey stick as ur throwing arm u would get a lot of whip
Why arms instead of a wheel?
@ACDC5968: I honestly haven't decided what's next. I keep playing around with combinations of what First in Fright and MURLIN in my head, but a good systems design hasn't emerged yet
I have attempted to send you a request four times, and am getting it bouncing back, no such address exists. I would very much like the plans, and agrre to the conditions. Thank you for all your hard work
@OldFatSlowGuy44 : Well, the computer does the bulk of the optimizing, using a genetic algorithm and sequential throws to evolve the length of each of the arms. Because this technique is blind to the 'why' question, simply trying slight modifications and saving them when the distance improves, I'm not sure why arm 4 is longer than arm 5. Perhaps it has something to do with how and when the projectile comes out of the cradle. It's a pretty good question.
LV
Are you still giving out plans? I have emailed you but I just wanted to check if you still used this channel or the email.
a VERY nominal price? lol
Dear Leonard, are you still sending out plans? I have tried to email you but without success so far.
Daniel: I have them for free on the website 'tucsonpumpkintoss.org'. let me know if you have trouble.
Leonard Vance thank you so much! For some reason it is not found by google.
sashafortis: I've been distributing the plans as normal from murlintrebs at gmail.com over the past week, so I'm not sure what's giving you trouble. If you send me an email address, then I will forward plans