you're right, the fins would need to be angled.
It's pretty simple to do.
Just make some fins attached to a shaft and shove the shaft up the wet clay glandes bracket
If you make sure a little of the fins is also in the clay, it should hold it pretty tight when it dries.
Or the glande will split - one or the other

Right so whle the torus dries, I've gone back to the aerofoils.

I've got a basic hollow cylinder with thick base tapering to a thin top.

I've also added angled slits that should orient on the angle of rotation.
I've then tilted those so that the slits actively funnel air into the interior of the cylinder.

I have no idea if this is a good idea or not. But it makes the 'tail' lighter and we've already established I like pushing air through holes - so why not

So first rigid 'aerofoil plus' sling missile.
Yeah it's rough, this thing was printed at saffy's top speed.
100% functional, just not pretty

Weighs about 17gm and feels pretty substantial.

Yep - I'll try and get the parcels out next week. With various goodies

Meanwhile I've got a bunch of aerofoils to test.
Going to see if I've got a more appropriate sling to throw them with.
Either a split pouch or a flat leather pouch would probably be more suited.

These two look pretty good. Though the Tibetan type one is pretty long, the aerofoils might not be heavy enough. We'll see

Be interesting to see if
1) they will sling.
2) throwing with a stick is better than sling
3) if the slits make any difference

So anyway, back to the torus that's been drying out.

for some reason minimal shrinkage.
The outer diamater is still 12mm.
The widest part of the interior gap has gone from 21mm to just 20mm.
While the gap from the edge of the interior to the central hub has not changed at all.
started out at 11mm and after 2 days is still 11mm.

So i can just make a blade insert the same size as the hole in the wet clay. And it should just shrink to grip, but nowhere near enough to break the torus.
Must be something specific to the shape - glandes tend to shrin a lot more.

I'll take the torussessessess (Tori ?) For a walk tonight, didn't have time yesterday.

Haven't decided on a fan design yet, I'll have a play this afternoon.

The Torissies (lol) don't throw well by hand - just too heavy.

Might make a simple flat pouch sling for them as well.
We'll see

Magnus effect - well yes I did notice that

Now I did take a couple videos. But honestly, with the phone in one hand and the sling in the other, it does not make for great video.

So before I take pics of the wreckage and try and salvage a half reasonable bit of footage I'll go through my observations.

Throwing with a stick, whittled smooth.
No difference between slotted and solid.
I tended to throw high, with more practice I'd get it straighter.
Didn't travel terribly straight.

But with a sling, very noticeable difference.

They both went further, probably 30-40 metres.
Fig 8 with a good vertical release, went well as did a  multi rotation windup and sidearm throw.

Unfortunately with the phone in one hand fig 8 is tricky.

And then there was the other problem
Phoebe and dream

Yeah, while neither brought them back to me, they did enjoy chasing them and giving them a good crunch.
So I reckon a got an average of 1.5 throws per aerofoil.

And the results are:

The solid ones flew quite well, not terribly straight - I was either throwing into the wind or across the wind - but they flew correctly oriented, just not terribly straight.

The grooved/slotted ones flew a lot straighter and tended to climb quite steeply as well.
When I got one the wrong way round, they just dived into the ground. So the grooves were definitely both giving lift and also keeping them straighter.

So if I cut down on the number of slots, they should go further and straighter.

I'd have liked to do a lot more throws, but after about 15 minutes all I had left was bits

So I really need to go down with the tripod and also make the aerofoils out of the flexible tpu, which should be a lot more dog proof

But as far as this short test goes.
Yeah, they throw quite well. Once I get the number of grooves right so they go more forward than up, should get some reasonable distance.
Tempted to up the diameter to 35 or 40, which will not only give more overall weight but more wing area.

I've got the length about right. I tried a couple that had been bitten in  half, and they were rubbish.

So maybe go up to 40mm diameter and 60 or 70mm length, and make them from 'chewable' polyurethane. And reduce number of slots.

But yep, fun new ammo type.

When I've got the design nailed down, I'll attach the stls.

Without such enthusiastic helpng friends, the crunchy pla ones would probably last for years

Oh yeah I ended up just using the shepherd's sling in the end. Just worked really well. I think it's one of Pete's, but wouldn't swear to it.

Attached pic of bits I could find, looks like I missed a couple.

I love the idea of threading them on a straight stick.  Thats some good thinking outside the box there. I actually am wondering if theres a way to make that a viable hard hitting weapon because it seems like it would be so easy to aim.

I couldnt see much from the flight but thats to be expected since you are holding the phone. I saw the two most important parts though: phoebe and dream. What kind of silly pups play fetch with a mans experimental aerofoil ammo?

copy and paste this script into openscad ( www.openscad.org )
Quote:


Once you've adjusted the parameters - press 'f5' for a quick preview and 'f6' for a full render (it can take a little time depending on your single core processor speed).

If you come up with a design/ size you want me to try, no need to upload the exported stl file, just screenshot your settings and I'll make it and see how it flies. Video not guarenteed