Pumkin Chunkin

[Tibertus]

Gee, I sure wouldn't want to get this BBS off on a tangent. BUT having watched my first Pumpkin Chunkin competition on Discovery Channel the other day... I did notice a lot of machine work, and interesting welding that must of been done in home shops. So do you think we'll be seeing any articles in HSM or threads here about that great hobby??? Maybe they have their own BBS?
I wouldn't want to see us miss out on an exciting new manly sport, and excuse for excessive festivities (actually there were women participating too).

Peace

[Paul Gauthier]

I saw the program also, found it most amazing.

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Paul G.

[Jim Caudill]

I saw it too! Pretty interesting, especially the centifugal units. Man, it kinda scared me seeing those things wind up. And how do they know how to trip the release. The faster it is going the earlier the release would have to take place. I thought some of the tebuchets were really novel. Sure the cannons looked neat but I really admired the ingenuity of the other styles.

[wierdscience]

Did they have the guy with the air cannon mounted on the five ton military truck?Seems like he had a couple of 500 gallon air recievers and a 6"ball valve to do the work.I remember something like 800 yards?

[Thrud]

Ain't technology great?

Anyone see the "Junkyard wars" - "car throw" ?

Made me nipples hard it did. Oops! did I say that out loud? Ah, hell. It has preaty neat until the tribochet collapsed...

it still threw the Austin Mini about 5 meters!

[Rich]

You might want to check out the Backyard Ballistics site at www.frii.com/~bsimon/backyard.html.Follow the links for lots-o-pumkin goodies.Also note the plans for the pneumatic spud gun.Lots of fun for testosterone fueled male bonding activities.Our best launch was .2 mile with a shop built projectile----spuds are'nt that great for distance records.
Rich

[Rich]

WWW.frii.com/~bsimon/backyard.html

[Tibertus]

Weird Science

They had several of them there with the big trucks and air tanks etc. They were chunkin pumpkins about 1800 feet!!! WOW, wait I have to wipe drool from my face.
My question is how do you get started with a hobby like that? I guess you'd tell the wife your interested in Pumpkins, she'd think you was talking about a garden. By the time you're backing the flat bed semi trailer into the driveway with several sections of steam pipe, and a really big air compressor chained down, it'd be to late for her to notice the "stupid but happy grin" on your face. Once you have the truck parked and you're working she might just give up and either join you or at least put up with it. Remember the key to success in any hobby is "a willing spouse".
But then there were some women there with their own equipment that looked really cool and well thought out "Powered by Estrogen" was the name of their equipment.
This is what life in this age is all about.

Peace

[ShavingMaker]

OK, let's get technical. Mr Caudill stated that on the centrifugal units "The faster it is going the earlier the release would have to take place." Hmmmm.... If you ignore the centrifugal force, the released object would go off at a tangent at the point of release. What effect will the centrifugal force have on the final path of the pumpkin? Similar to a pitched baseball? Does it just affect speed or does it affect direction too?

[Jim Caudill]

Well, actually I usually don't get into these discussions but.... There really is no such thing as centrifugal "force". There is a centrifugal "effect" that is produced as the object being rotated wants to continue on the tangentail straight-line path. The actual point at which the retaining mechanism totally "releases" the pumpkin would have to be a function of its speed at release. Much like the angle of a barrel on an artillery piece. I would guess that the objective would be to have the pumpkin hit the ground at the instant that forward velocity reaches zero. If it hits with any forward velocity, then you could have released earlier and had greater height in your arc. If it ran out of forward velocity early, then you wasted precious energy elevating the pumpkin too high. It would seem that for "max range" the tangential angle (angle of the barrel) of release would get greater as the release velocity (muzzle velocity).

[docsteve66]

Jim: It has been years since I playedwith the math, but I think the tangent for max distance is a constant in theory. But in the real world (such as shooting artillry shells, the "drag" of the thrown object, density of the air, wheter you are shooting with or against the earths rotation, heck maybe even the phase of the moon affects the distance to hit ground. But as I rember it, you havetherest down pat.

Weren't logrithims invented (developed, discovered - what do you call originating a math process>?) to handle the complexities of shooting?

Steve

[lynnl]

I thought logarithms were invented so slide rules would work right, and to give math, physics, and engineering students some amusement. Aahh! ...to borrow a term someone used the other day, the "mists of time" have rendered a lot of that math stuff fuzzy nowadays. But, yes I too am thinking that for the parameter ranges relevent to a pumpkin in flight, that simply launching it at a 45 deg angle is gonna buy you the max range you can hope for. I'll try to remember to consult my pumpkin trajectory tables tonite and verify that. I didn't see the program recently, but from what you all are describing, I think I did see that program sometime ago...maybe a coupla years back. As far as the release point, I'd think the main variable would be the locktime (believe that's right term...help me out here gunsmiths) of the releasing mechanism, which would probably not be extremely consistent.

[This message has been edited by lynnl (edited 02-13-2003).]

[Paul Gauthier]

I believe on the the centrifugals the release mechanism is timed to the position of the rotating arm. That is, the release switch could be engaged at any point in the rotation of the arm but only when the arm was in the correct position would the "punkin" be released. Yes-no?????

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Paul G.

[Jim Caudill]

Yes, you're correct that there must be timing mechanism connected to the arm to control the release point. However, the issue is: Is this release point a variable that changes with rotational rpm or is it a constant. For example - there is an optimum time to ignite the gasoline mixture in our engines and it changes with rpm and the desired result ie. torque, horsepower, efficiency, etc. Therefore we have sophisticated boxes and sensors to match our objective (economy or passing power) to actual ignition timing vs piston position.

[wierdscience]

Think maybe the problem with the gun idea is after a certain point you get pumkin soup!So what I had in mind is a copy of the Gearld Bull super gun you know keep applying gas as the pumkin progresses down the barrel.Maybe we could get some of the shuttle heat tiles to counter the effect of air friction???What do you think??