The world speed record is broken

First topic message reminder :

Used audacity and the film 
"MANTIS Elite with uprated ENERGYWAVE technology gas spring."
to get 689 fps in Phil Abrahms Talisman Mantis crossbow.
That´s a remarcable word record ladies and gentlemen.


Congratulations Phil!

Thanks for the info on the Kolze double bow. I will gladly pay the small fee to read the article.

Someday, I plan to play around with these more radical designs. I think of them as more of a kinetic art project, or physics demonstration piece, so it doesn't have to be practical. 

Alan

This is what I get from the youtube sound track.
 
The shot at the 57 second point.  Microphone at the target so we need to add speed of sound from trigger to mic.
 
Recorded sound         .086 milliseconds
 
Speed of sound           1107.28346456693 feet per second
 
Range 60 feet             60/ 1107.28346456693 = 0.0541866666666666
Time to add
 
Recorded flight           .086 + .054 = 0.13919
time plus speed
of sound
 
Flight time                   0.13919 / 60 = 431 fps        
divided by 60 ft

Looks like you have the last word on this thread Hotspur.............................lol.
                                                                     Hermit.

Hotspur wrote:This is what I get from the youtube sound track.
 
The shot at the 57 second point.  Microphone at the target so we need to add speed of sound from trigger to mic.
 
Recorded sound         .086 milliseconds
 
Speed of sound           1107.28346456693 feet per second
 
Range 60 feet             60/ 1107.28346456693 = 0.0541866666666666
Time to add
 
Recorded flight           .086 + .054 = 0.13919
time plus speed
of sound
 
Flight time                   0.13919 / 60 = 431 fps        
divided by 60 ft

Yes, you are definitely right. I also get 0,086 seconsds on that arrow and since I usually place the microphone exacly halway to target, I have forgotten to involve the speed of sound in my calculation. Sorry! -I stand corrected! 

One more observation is thath arrow no 3 and 4 seems to penetrate the target less deep. Does the crossbow loose power or is the target used a lot so it has softer areas?

To mee it´s still an interesting design but it would be faster with this new lighter pivot-arms? Now it seems having the same speed as the website says it had with the old arms.

I earlier calculated the efficiensy to be around 60% and I guess the design would win on being an insving design allowing shorter (=lighter) arms but having the same powerstroke.

As said before only a real speed test can bring total thruth in this but it seems to be 431 fps right now.

Another thing -Please handle all users of this fine forum with respect.

Hotspur wrote:This is what I get from the youtube sound track.
 
The shot at the 57 second point.  Microphone at the target so we need to add speed of sound from trigger to mic.
 
Recorded sound         .086 milliseconds
 
Speed of sound           1107.28346456693 feet per second
 
Range 60 feet             60/ 1107.28346456693 = 0.0541866666666666
Time to add
 
Recorded flight           .086 + .054 = 0.13919
time plus speed
of sound
 
Flight time                   0.13919 / 60 = 431 fps        
divided by 60 ft

There is a fault in our calculations. We have measured the AVERAGE SPEED the arrow has during 20 yards of flight. 
To compare Mantis Elite with other crossbows we must calculate the speed the arrow has when it leaves the crossbow like we do with digital crony´s.

Take a look at the kinethic energy curve in this diagram frpm technicalarschery.com [url=https://f45668ba-a-62cb3a1a-s-sites.googlegroups.com/site/technicalarchery/technical-discussions-1/trajectory/trajectory example.png?attachauth=ANoY7co9ObQiwys6MQALFFjKMOGQJnbvuluHybqsLYYyB_OyCNJ7OHAG4NLpb5XGWHniCgdpoMq9v0ijrY_uoA3pfuUEs9oswU-gnpxtHxZQvrjLo4En0tqlb4uNEAnqjztgLSvTBefdKkPjCQUQqovKtH2KZw627RtMFCmppjdnPUR7IErmAHoJy8WRO2BZPU-F7n8CTTkiXqTpBqBlTkVhEDOKmyTg8aKU1xYz35oTmrntHoygjuPxaqHOewe6mY1doNJII8vodBU-KXfbG9KHv9awFoqGoQ%3D%3D&attredirects=0]https://f45668ba-a-62cb3a1a-s-sites.googlegroups.com/site/technicalarchery/technical-discussions-1/trajectory/trajectory%20example.png?attachauth=ANoY7co9ObQiwys6MQALFFjKMOGQJnbvuluHybqsLYYyB_OyCNJ7OHAG4NLpb5XGWHniCgdpoMq9v0ijrY_uoA3pfuUEs9oswU-gnpxtHxZQvrjLo4En0tqlb4uNEAnqjztgLSvTBefdKkPjCQUQqovKtH2KZw627RtMFCmppjdnPUR7IErmAHoJy8WRO2BZPU-F7n8CTTkiXqTpBqBlTkVhEDOKmyTg8aKU1xYz35oTmrntHoygjuPxaqHOewe6mY1doNJII8vodBU-KXfbG9KHv9awFoqGoQ%3D%3D&attredirects=0[/url]   

and see the arrow has lost 20% of it´s KE after 20 yards. This is because of drag and is probably an exact curve of the arrow´s speed losses.

This will say Mantis Elite has a speed of 431 fps +20% wich will take it well over 500 fps.

Congratulations Phil! You have made the worlds existing fastest crossbow in production!

MR, Oppenheimer.  You say this mantis is in  production?  
Last I talked with Phil, there was not a mention  yet.Cause that is an interesting machine. Problem is ,no one in the crossbow or archery world will call it a bow. There in lies the problem. In the US, you could not obtain a hunting permit to use it.Record holder or not makes no difference.

Hey C sitas, why would this not pass as a crossbow in the US?, seems like a crossbow enough to me.

Mr. Oppie,  It's like this . Where is the energy that runs the machine stored? Is it a bow?  This is not just the US. The only reason I mention the US. is because I think that would be his best market. I love the idea, but, where can you purchase? Also ,If you check the UK> specs. on what is legal for competion you will run into trouble again.

c sitas wrote:MR, Oppenheimer.  You say this mantis is in  production?  
Last I talked with Phil, there was not a mention  yet.Cause that is an interesting machine. Problem is ,no one in the crossbow or archery world will call it a bow. There in lies the problem. In the US, you could not obtain a hunting permit to use it.Record holder or not makes no difference.

You know very well that the energy is stored in a gas spring. The only people negative to this crossbow is the one´s conected to the existing crossbow companies int the US. They are afraid of concurrence. That´s why they have used political lobbying to stop it.
In hunting I see no difference between Mantis and normal guns or bows.
As you say -It´s all about money.

I myself welcome Phil Abrams Mantis because it´s an inovation and I thought this forum was for people inovating, building and just DOING things (instead of me just reading about them).

Here we are free here to dream and make.Not so in the rest of the world.At one time I thought Phil had backing money to go ahead but , that must have fallen through. Also since then ,I've not heard from Phil. Remember , there was another guy playing at the same time . I don't recall his full name . I think it was warhammer. He also had a great idea. I have worked some off of his idea cause it was a much simpler design.Used springs also.Both were going great until it came time to explain how things worked.