Let me tell you that with Hondero's design, I had the arrowhead lower than the tail. With your design it is imperative to have the arrowhead higher than the tail (to keep the dart in the sling).

This is what I find, anyway.

My tests were only at short range (15m) and low speed, however. Perhaps better tests tomorrow!!!

Yurek
Your design works!
I have a very rough, clumsy built dart, and I was able to hurl it with your sling design. I think if I had a proper dart, it work go much futher. It seems to look more like the one Livy described in his histories(the sling that is). Very simple!
Thanks for your efforts!
Johnny

Robert,
First, welcome to the forum. The plumbata is a different thing from cestrosphendon. It is longer than the dart of the cestros and as you explain it is weighted with a lead ball in the center of the shaft,  and it´s sent by hand. I have made and used the plumbata and it has nothing to do with the cestros. The cestros can almost reach the same distance that a stone of the same weight sent with a conventional sling, that is, hundreds of meters. The energy that takes the dart can penetrate armors and kill a man or blow away an arm. The Romans didnd´t use the cestros, maybe because of its difficult operation. They were very practical people.
In regard to the folk sport called 'arrow-throwing' in Yorkshire, England, the arrow is a simple shaft and the cord is a simple string with a knot at the end. A loop is made over the shaft by that end, being joined on the knot, on which it slid at the end of the launching freeing itself (don´t know if it is well said  ???). It is a very simple design and works very well. It can be used with conventional bow arrows too.

Yurek,
the inventors nook was forgotten and I am glad that you bring here your ingenious designs again . I have to try it, but at first I see a difficulty in the position of the arrow. Being horizontal and the cords very opened, when turning around they are going to tangle. That also happens with the conventional design of cestrosphendon when the dart is placed in a quite horizontal position. In fact, and to avoid it, the best position is very inclined, almost vertical, with a limit of 30 degrees on the vertical.

Mithras,
I see that you have had some difficulties with the conventional cestro  . Well, I´ll tell you the secret of its operation. As I said before, its position must be enough vertical so that the cords are not tangled, and the most important is to avoid that the point nail on the little pocket. Put simply a small piece of leather between the point ant the pocket and the dart will leave straight ahead without being stuck in the pocket. There are other solutions, but I prefer you guys to experiment until finding them, and thus can appear new designs and solutions, as the ingenious design of Yurek. The innovation to the power!

Johnny, Chris, Hondero,

Thanks for the welcome!

Johnny,
So you're a 3rd-c. nutter, too, eh? Well, I do 4th c. mainly, but it's but a small step back in time to you. Thanks for the praise btw.
The ref. for arrow-throwing is:
Payne-Gallwey, Ralph (1903): The Book of the Crossbow, pp. 243-6 (Dover, reprint 1995):http://biologybooks.net/search_Ralph_Payne-Gallwey/searchBy_Author.html.
I'll post a scan of the throwing technique.

I have not read up on slingers during the 7th
century, but I do know they were massively recommended. Most infantrymen would have had slings with them, we're not talking about a specialist unit.

Yurek,
That's a brilliant design! I will try that instead of the cestos, which indeed seems problematic for longer darts.

Chris,
Thanks for the welcome. Indeed, darts go a lot further, but what did they look like in the 5th and 6th century is a bit of a mystery. or why they eventually went out of fashion.

Hondero,
Yes, you are of course correct, the plumbata is not the same as a cestos. However, we don't know anything about the actual length (no shafts survived), nor of the actual delivery method. It could be very short, it could be as long as 60 cm. The weight is mostly 10-15 cm from the point, not in the centre. So yes, it is different from the cestos (otherwise we could assume at least the Byzantines would have used that name), but you can’t say a plumbata was not thrown by a sling.

I assume the range of the plumbata will have been less because of the weight. Furthermore, the weight makes this weapon different, in that it is meant to land vertically.

Your description of 'arrow-throwing' is very accurate, but then I’ve seen pictures.  I’ll post one here soon.

Cheers,
Robert

Here's a recent close-up of my lefty son about to cast the cestrosphendon:

http://img78.photobucket.com/albums/v299/lord_mithras/History1/cestros2.jpg

i made one of these i was very impressed I made a very modern dart using  31inch 2219 true flight alum arrow
i cut it down to 19 inches filled last five inches full of lead and stuck a field point on it fly's great  my back yard target area is only fifty yards so i had to go light to stay on the range

How did you fill the last few inches with lead? I have also made one from an old arrow. They make good lawn darts too.

Johnny, yes, my son is a dab hand at slinging but has not used the kestros much. It was a great little weapon until the dart snapped (twice!!) at the join between wood and metal.

I've recently joined Comitatus, a Late Roman group and we use a dart staff sling. Now the thread layout isn't great and 50% time gets fouled (not good in front of a crowd). I've rigged up a new system and made my own sling and blunt dart to test it on. It works like a damn dream at the moment (gentle flights in the garden).

http://img.photobucket.com/albums/v299/lord_mithras/History1/DSCF1179.jpg

On Saturday I hope to give it the full 100% test-fly!