Chakram upper surface profile

Timo Nieminen · 20th June 2014, 06:17 AM

... or chakra, or quoit.

Payne-Gallwey, in his talk at the Royal Institution of Britain meeting, 1908 (reprinted in A. G. Credland, "Sir Ralph Payne-Gallwey Bt. and the Study of Medieval and Ancient Projectile Weapons", Arms & Armour 8(1), 46-88 (2011)) describes the chakram:

"It is made of the finest sword-steel, and is usually eight inches in diameter, including its inch-wide rim. It is a sixteenth of an inch thick and eight ounces in weight. [...] The upper surface of the quoit, or the surface that is held uppermost when the quoit is thrown, is slightly convex. The under side is flat."

Thinking that it might be interesting to make a replica (maybe a safe non-steel replica for playing with), and that "slightly convex" is very general, I ask: what is the profile of the upper surface in more detail? Is it very stereotyped, or does it vary a lot from chakram to chakram? Since it's an aerodynamic weapon, the details of the profile might affect the performance a lot.

Payne-Gallwey on the performance of the chakram:
"I have often thrown one of these quoits over 200 yards, its height above the ground, for two-thirds of its flight, not exceeding 4 or 5 feet. This shows what a deadly weapon it must have been in warfare when used by the native soldier, who could doubtless cast it with much more force and precision than I can."

DhaDha · 21st June 2014, 06:39 PM

Intriguing weapons. I was lucky enough to pick one up a while back and might provide some insight.
This one is the same type and sporting the same mark as shown on top of page 314 in Robert Hales' new book. It is convex on both sides, like a sword. Made of great steel and rings like a bell as they say… It is a little larger, about 9.5 in and although I have not thrown it, it feels great to hold.
I look forward to hearing more about your project…

Jim McDougall · 21st June 2014, 10:47 PM

I don't have anything to add here at this point, but I just wanted to thank you guys for the detail in adding references in these posts! These are most interesting weapons and material is pretty obscure, so its great to have a benchmark for researching further and discussion.
Much appreciated and thank you so much!!

Jim

Runjeet Singh · 22nd June 2014, 06:58 PM

Hi Timo,

A subject close to my heart as you can imagine.

From the examples I have handled and have in my collection, I can tell you the earlier specimens DO have an 'Airfoil' or 'Convex' profile. The chakrum itself has an almost very narrow 'diamond' section profile, but a close inspection does reveal a slight 'aerfoil'.

In examples which I believe are later, the 'Airfoil' is more pronounced. I cant tell you which is better, I have never wanted to throw old chakrum around, although I cannot imagine it would damage them if thrown in open ground. Perhaps I will give it a go one day!

The British historian Mike Loades made a documentary under the series 'Weapons Masters' which some of you may have already seen. A very interesting and useful introduction to the Chakrum and aerodynamics of the object, I think it's a definite watch for you Timo.

Here is the link, although others in the States have told me it is not viewable there, perhaps it will work this time. If you cannot view it, let me know and I will see if there is another way to access the programme.

https://www.youtube.com/watch?v=sev9LmC_d_4

Good luck in your quest, and if you have any other questions feel free to ask.

Sincerely,
Runjeet

Battara · 22nd June 2014, 07:57 PM

Great info Runjeet! Unfortunately the link still doesn't work for us in the States....

Runjeet Singh · 22nd June 2014, 09:53 PM

Thanks for letting me know Jose. I will look into this, and see if I can come up with a solution. Hopefully Timo can view it thought?

Regards
Runjeet

estcrh · 22nd June 2014, 11:00 PM

Quote:

Originally Posted by Battara

Great info Runjeet! Unfortunately the link still doesn't work for us in the States....

For those situations were your location keeps you from accessing certain internet addresses you can use "Hola", I just watched the video (very interesting) using it. https://hola.org/

Runjeet Singh · 23rd June 2014, 10:08 AM

Great tip Eric, thanks.

Apparently the documentary is also streaming on Netflix.

Thanks,
Runjeet

Timo Nieminen · 23rd June 2014, 09:24 PM

Quote:

Originally Posted by Akaalarms

Thanks for letting me know Jose. I will look into this, and see if I can come up with a solution. Hopefully Timo can view it thought?

Works for me; many thanks! (Now I need to have time while in front of a computer with working sound, or fix the sound on mine.)

DaveA · 3rd July 2014, 02:12 AM

Hello,

Here is a small picture of my chakram. It measures 9 ⅜ inches in diameter. The ring is beveled in a diamond cross section to generate aerodynamic lift. In shape, it very much resembles the modern "Aerobie" toy which was reportedly modeled on the charm. The patina of my example is mottled gray with light pitting. The composition is radial patterned steel, pattern welded for strength and not for esthetic effect. In other words, a weapon intended for use and not simply show.

Interestingly, steel versus brass chakra have different throwing distances. A steel one such as this has an effective range of 40 to 50 meters. A brass chakrum, due to lower mass, could be thrown in excess of 100 meters.

Here is a link to my website with further information:

Chakkar Sada Chakrum

Best Regards,

Dave A.

Timo Nieminen · 3rd July 2014, 02:38 AM

Why are brass ones lighter? Are they smaller, thinner, or hollow on the bottom surface? (Brass being denser than steel, there must be a smaller volume of metal compared to steel ones.) Are the brass ones non-weapons?

(Maybe the best thing to do is to get an Aerobie and copy it in steel.)

Timo Nieminen · 5th July 2014, 04:53 AM

Quote:

Originally Posted by Akaalarms

The British historian Mike Loades made a documentary under the series 'Weapons Masters' which some of you may have already seen. A very interesting and useful introduction to the Chakrum and aerodynamics of the object, I think it's a definite watch for you Timo.

Here is the link, although others in the States have told me it is not viewable there, perhaps it will work this time. If you cannot view it, let me know and I will see if there is another way to access the programme.

https://www.youtube.com/watch?v=sev9LmC_d_4

Here is a different version, same uploader, which might be more easily viewable for some: https://www.youtube.com/watch?v=sDNw2slOK3Y

20th June 2014, 06:17 AM	#1
Timo Nieminen Member Join Date: Mar 2012 Posts: 422	Chakram upper surface profile ... or chakra, or quoit. Payne-Gallwey, in his talk at the Royal Institution of Britain meeting, 1908 (reprinted in A. G. Credland, "Sir Ralph Payne-Gallwey Bt. and the Study of Medieval and Ancient Projectile Weapons", Arms & Armour 8(1), 46-88 (2011)) describes the chakram: "It is made of the finest sword-steel, and is usually eight inches in diameter, including its inch-wide rim. It is a sixteenth of an inch thick and eight ounces in weight. [...] The upper surface of the quoit, or the surface that is held uppermost when the quoit is thrown, is slightly convex. The under side is flat." Thinking that it might be interesting to make a replica (maybe a safe non-steel replica for playing with), and that "slightly convex" is very general, I ask: what is the profile of the upper surface in more detail? Is it very stereotyped, or does it vary a lot from chakram to chakram? Since it's an aerodynamic weapon, the details of the profile might affect the performance a lot. Payne-Gallwey on the performance of the chakram: "I have often thrown one of these quoits over 200 yards, its height above the ground, for two-thirds of its flight, not exceeding 4 or 5 feet. This shows what a deadly weapon it must have been in warfare when used by the native soldier, who could doubtless cast it with much more force and precision than I can."

21st June 2014, 06:39 PM	#2
DhaDha Member Join Date: Jun 2006 Posts: 163	Intriguing weapons. I was lucky enough to pick one up a while back and might provide some insight. This one is the same type and sporting the same mark as shown on top of page 314 in Robert Hales' new book. It is convex on both sides, like a sword. Made of great steel and rings like a bell as they say… It is a little larger, about 9.5 in and although I have not thrown it, it feels great to hold. I look forward to hearing more about your project… Attached Images

3rd July 2014, 02:12 AM	#10
DaveA Member Join Date: Apr 2007 Location: Wisconsin, USA Posts: 413	For comparison, my Chakrum Hello, Here is a small picture of my chakram. It measures 9 ⅜ inches in diameter. The ring is beveled in a diamond cross section to generate aerodynamic lift. In shape, it very much resembles the modern "Aerobie" toy which was reportedly modeled on the charm. The patina of my example is mottled gray with light pitting. The composition is radial patterned steel, pattern welded for strength and not for esthetic effect. In other words, a weapon intended for use and not simply show. Interestingly, steel versus brass chakra have different throwing distances. A steel one such as this has an effective range of 40 to 50 meters. A brass chakrum, due to lower mass, could be thrown in excess of 100 meters. Here is a link to my website with further information: Chakkar Sada Chakrum Best Regards, Dave A. Attached Images

21st June 2014, 10:47 PM	#3
Jim McDougall Arms Historian Join Date: Dec 2004 Location: Route 66 Posts: 9,738	I don't have anything to add here at this point, but I just wanted to thank you guys for the detail in adding references in these posts! These are most interesting weapons and material is pretty obscure, so its great to have a benchmark for researching further and discussion. Much appreciated and thank you so much!! Jim

22nd June 2014, 06:58 PM	#4
Runjeet Singh Member Join Date: Oct 2006 Location: Warwickshire, England Posts: 150	Hi Timo, A subject close to my heart as you can imagine. From the examples I have handled and have in my collection, I can tell you the earlier specimens DO have an 'Airfoil' or 'Convex' profile. The chakrum itself has an almost very narrow 'diamond' section profile, but a close inspection does reveal a slight 'aerfoil'. In examples which I believe are later, the 'Airfoil' is more pronounced. I cant tell you which is better, I have never wanted to throw old chakrum around, although I cannot imagine it would damage them if thrown in open ground. Perhaps I will give it a go one day! The British historian Mike Loades made a documentary under the series 'Weapons Masters' which some of you may have already seen. A very interesting and useful introduction to the Chakrum and aerodynamics of the object, I think it's a definite watch for you Timo. Here is the link, although others in the States have told me it is not viewable there, perhaps it will work this time. If you cannot view it, let me know and I will see if there is another way to access the programme. https://www.youtube.com/watch?v=sev9LmC_d_4 Good luck in your quest, and if you have any other questions feel free to ask. Sincerely, Runjeet

22nd June 2014, 07:57 PM	#5
Battara EAAF Staff Join Date: Dec 2004 Location: Louisville, KY Posts: 7,139	Great info Runjeet! Unfortunately the link still doesn't work for us in the States....

22nd June 2014, 09:53 PM	#6
Runjeet Singh Member Join Date: Oct 2006 Location: Warwickshire, England Posts: 150	Thanks for letting me know Jose. I will look into this, and see if I can come up with a solution. Hopefully Timo can view it thought? Regards Runjeet

23rd June 2014, 10:08 AM	#8
Runjeet Singh Member Join Date: Oct 2006 Location: Warwickshire, England Posts: 150	Great tip Eric, thanks. Apparently the documentary is also streaming on Netflix. Thanks, Runjeet

3rd July 2014, 02:38 AM	#11
Timo Nieminen Member Join Date: Mar 2012 Posts: 422	Why are brass ones lighter? Are they smaller, thinner, or hollow on the bottom surface? (Brass being denser than steel, there must be a smaller volume of metal compared to steel ones.) Are the brass ones non-weapons? (Maybe the best thing to do is to get an Aerobie and copy it in steel.)