Animation/Video

Wow that is slick! What a cool animation..

That is good! Any ideas what was used for the animation? Could Inventor do it? The mech. designers I work with use Inventor, and I've seen them do some pretty cool stuff, but that would take a month of Sundays!

Wow!!! amazing video / animation.

Amazing design for a 'humble' bow as well!!!

Yeah, they are freaky to pull, the draw weight increase, and just as you are thinking...'this is getting pretty heavy' the cams come over and the weight comes off allowing you to hold it at full draw comfortably. The amimated bar graph of draw weight was showing that, but it may not have been obvious what it meant.
Del

The bar graph was the best part of a great piece, showing at what point maximum energy is being transferred into the arrow.

LL

drI recently made an Asiatic recurve with rigid levers (Siyahs) at the limb tips. It gives a vaguely similar sort of effect insofar as it gives a higher initial draw and the poundage increases more slowly than a longbow.
I may blog it up later if it's of interest. Here's a graph of draw weight vs draw length for it vs my longbow. (If the final draw weight were the same the Asiatic bow would be storing more energy)

It performs ok for a first attempt, and it would be interesting to experiment with different geometries.
You can see where the levers kick in at about 12"draw.

Del

Do you have pictures?

Do you also have velocity figures comparing the bows?

Or, perhaps, penetration figures into a medium?

I'm not a bowman. I do have a 1980's compound bow around, somewhere.

You guys don't shoot arrows up into the air and time how long they take to come down, do you?

I'm submitting a blog on it, with loads of pics so keep a look out...
I don't have figures (I havn't built my arrow speed chronometer yet.
It shoots nearly as far as the longbow using the same arrows (210yards ish)
I'd guess if I used a longer flight arrow say 32" It would probably make 250yards.
It's a shame it didn't end up the same draw weight as the longbow...but why that happened is explained in the blog.

The energy strored in the bow is proportioanl to the area under the graph, so you can see that in the first half of the draw the Asiatic bow has more strored energy.

Penetration is very much a function of the arrow head. Field points are designed for limited penetration, a broadhead would slice through a foam target.

I could have tested it on the door of our fridge freezer which has just gone belly up..but Mrs Cat wouldn't let me.
Del

that's great.. I want!.. I need!

Is it from here?

...nice final projects..

good class

...can you tell Mrs Cat that you need to take the door off that old fridge freeze anyhow?

at least you can ventilate it right away!

Dunno the origins of the clip...I took it off Archery-Interchange website where someone had posted it.
Tooo late the fridge freezer has gone to the dump, tip, civic recycling amenity

Del

"Is it from here?"

Reading from the link, sounds like it probably is - assuming the same course is still running (link is from 1998).

Answering my Q (#2), to quote from the Berkeley link ...

"The software used for the course is AutoCAD, R 13, for computer-assisted-drawing. AutoDesk Mechanical Desktop will be used for parametric modeling. AutoDesk 3-D Studio, R3, will be used for solids rendering, presentation, and animation."

... so I'd guess they're probably into Inventor, 10 years on.

Good one, thanks.

Excellent, Del! Kudos for an extremely well done video. I was surprised that in your exploded view, you had no parts left over after re-assembly!! A very professional job! Have you, or your designers, contacted different manufacturers to try and market this animation technology? Don't forget the military to illustrate how weapons and vehicles, airplanes, etc are assembled and how they work!! This could be a significant learning tool! Good luck!!

NO NO NO... it's not my work....
I just linked to it for you guys to see.
I wouldn't want to take credit for someone else's work...

Del _{(Me with a compund bow! ? Shirley not.)}

Thats just scary how much engineering time has gone into that... the actual development of the technology, and then the rendering and animation... way beyond!

Thats no moon.. its a compound bow!

Chris

That's impressive! Some close tolerance work involved in building the thing.

Del, many thanks for the link. Not just awe inspiring, idea inspiring. Simon

I am sure I would like it if I could see it - YouTube was recently blocked in China.