RDT (Reverse Draw Technology) crossbow building

by patandjali Sat Mar 29, 2014 11:49 pm

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Post n°1

RDT (Reverse Draw Technology) crossbow building

by patandjali Sat Mar 29, 2014 11:49 pm

Reverse bow system has many advantages besides classic crossbow:
-center of gravity of the crossbow is exactly in the middle
-Is much narrower, it can maneuver more easily
-no shock at shooting
-in a relatively short crossbow very long Power Stroke.
-long Power Stoke- higher speed.

Materials

materials we need to build
- aluminum-plate 8 mm
- leaf spring 6mm
-hardwood
-bowstring materials
perseverance Very Happy

by patandjali Sun Mar 30, 2014 12:14 am

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Post n°2

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Sun Mar 30, 2014 12:14 am

LINK fixed
https://www.youtube.com/watch?v=JPc1tAUo01E

Last edited by patandjali on Sat Jun 07, 2014 10:51 pm; edited 1 time in total

by patandjali Sun Mar 30, 2014 12:21 am

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Post n°3

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Sun Mar 30, 2014 12:21 am

some pictures
http://www.kephost.com/view3.php?filename=a1_2014_3_30_xwsersmnlm.jpg
http://www.kephost.com/view3.php?filename=a1_2014_3_30_xq08oqtcmf.jpg
http://www.kephost.com/view3.php?filename=a1_2014_3_30_ki4jdb6de4.jpg

by phuphuphnik Sun Mar 30, 2014 4:49 am

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Post n°4

Re: RDT (Reverse Draw Technology) crossbow building

by phuphuphnik Sun Mar 30, 2014 4:49 am

That is a mean looking little bow! Is there a cocking assist, or is it hand spanned? I was looking at modern crossbows ( a Barnett Razr), and they were very front heavy, the balance you describe would make for more precise shooting.
cheers,
chriso

Aceasta este o medie în căutarea arc mic! Există o armare asista, sau este calibrat mână? M-am uitat la arbalete moderne (un Razr Barnett), și au fost foarte grele din față, echilibrul pe care o descrieți-ar face pentru fotografiere mai precise.

Last edited by phuphuphnik on Sun Mar 30, 2014 5:04 am; edited 1 time in total (Reason for editing : tranlated to Romanian)

by Todd the archer Sun Mar 30, 2014 7:39 am

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Post n°5

Re: RDT (Reverse Draw Technology) crossbow building

by Todd the archer Sun Mar 30, 2014 7:39 am

Great job, well done!

Todd

by Hotspur Sun Mar 30, 2014 10:36 am

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Post n°6

Re: RDT (Reverse Draw Technology) crossbow building

by Hotspur Sun Mar 30, 2014 10:36 am

Very nice!

Is there anything you would change?

by patandjali Sun Mar 30, 2014 11:01 am

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Post n°7

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Sun Mar 30, 2014 11:01 am

Link fixed
https://www.youtube.com/watch?v=qYLzUSHT7QY

Last edited by patandjali on Sat Jun 07, 2014 10:53 pm; edited 1 time in total

by MRobin Mon Mar 31, 2014 4:52 am

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Post n°8

Re: RDT (Reverse Draw Technology) crossbow building

by MRobin Mon Mar 31, 2014 4:52 am

Damn nice, what speed?

by Anatine Duo Mon Mar 31, 2014 8:12 am

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Post n°9

Re: RDT (Reverse Draw Technology) crossbow building

by Anatine Duo Mon Mar 31, 2014 8:12 am

pretty nice, always great to see handmade cams!

by patandjali Tue Apr 01, 2014 9:35 pm

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Post n°10

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Tue Apr 01, 2014 9:35 pm

Thx,boys

The arrows ballistics test on the top.
http://www.excaliburcrossbow.com/content/arrow_ballistics
https://www.youtube.com/watch?v=gpLxB2sFYs4&feature=youtu.be

by phuphuphnik Wed Apr 02, 2014 4:39 pm

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Post n°11

Re: RDT (Reverse Draw Technology) crossbow building

by phuphuphnik Wed Apr 02, 2014 4:39 pm

I built one of these coil chronometers. It works well until you shoot one of the coils...

http://www.archerytalk.com/vb/showthread.php?t=1485256

by Hotspur Wed Apr 02, 2014 6:55 pm

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Post n°12

Re: RDT (Reverse Draw Technology) crossbow building

by Hotspur Wed Apr 02, 2014 6:55 pm

There is the tried and true ‘click-thwack’ method of determining average bold speed:

Put your cell phone in the middle of the range (try not to shoot it). The middle of the range cancels out speed of sound error.

Turn on an audio recording app.

Shoot.

Look at the audio file ‘click-thwack’ in Audacty http://audacity.sourceforge.net/ and measure the milliseconds of flight time.

RDT (Reverse Draw Technology) crossbow building Audacity_zps168b422d

RDT (Reverse Draw Technology) crossbow building Audacity_zps168b422d

by phuphuphnik Thu Apr 03, 2014 12:33 am

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Post n°13

Re: RDT (Reverse Draw Technology) crossbow building

by phuphuphnik Thu Apr 03, 2014 12:33 am

Hotspur, that is brilliant!

by Hotspur Thu Apr 03, 2014 7:48 am

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Post n°14

Re: RDT (Reverse Draw Technology) crossbow building

by Hotspur Thu Apr 03, 2014 7:48 am

I wish I could take credit, but I swiped the idea here somewhere Smile

A couple of tips: download an app that records in an Audacity friendly format like mp3.

The button second from the top right 'Fit Selection' zooms in to whatever is highlighted. Then if you highlight your shoot sound the time is displayed in the bottom centre readout. In the photo it says .247, my range was 50 feet so: 50/.247 is 202 feet per second.

Important to note this is the average speed and not a chronometer muzzle velocity. Some smarty-pants math type might be able to write us an Excel equation to calculate muzzle velocity? Anyone? Smile

by patandjali Thu Apr 03, 2014 12:14 pm

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Post n°15

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Thu Apr 03, 2014 12:14 pm

Thank you

305 fps arrow broadheads(650 grains) 325 fps arrow > 540 grains ,350 fps arrows >460 grains Very Happy

Last edited by patandjali on Sat Jun 07, 2014 11:02 pm; edited 1 time in total

by Hotspur Thu Apr 03, 2014 5:57 pm

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Post n°16

Re: RDT (Reverse Draw Technology) crossbow building

by Hotspur Thu Apr 03, 2014 5:57 pm

patandjali wrote:Thank you
325 fps arrow 30 gramms

Wow, very nice!

by Hermit Sun Apr 06, 2014 8:24 am

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Post n°17

Cam questions

by Hermit Sun Apr 06, 2014 8:24 am

I have no experience at all with cam action bows,so have some questions about how this bow is strung.
1)Is the string a closed loop
2)If the string is not a closed loop,how is is secured.From the photographs,it appears to to be fixed somehow to the small cams.If it's possible,a photograph showing how the string is secured would be extremely helpful,and very much appreciated,as I am completely stuck on this.
Hermit.

by patandjali Sun Apr 06, 2014 12:29 pm

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Post n°18

Re: RDT (Reverse Draw Technology) crossbow building

by patandjali Sun Apr 06, 2014 12:29 pm

Here you are,if you'll help
http://www.kephost.com/view3.php?filename=a1_2014_4_6_560zpei5e7.jpg
http://www.kephost.com/view3.php?filename=a1_2014_4_6_ywdgn9h3ph.jpg
http://www.kephost.com/view3.php?filename=a1_2014_4_6_o962k6d629.jpg

https://www.youtube.com/watch?v=RMKS4lL8sG0

by phuphuphnik Sun Apr 06, 2014 12:37 pm

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Post n°19

Re: RDT (Reverse Draw Technology) crossbow building

by phuphuphnik Sun Apr 06, 2014 12:37 pm

Those cams are wonderful sir ಠ_ರೃ

by Hermit Mon Apr 07, 2014 8:16 am

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Post n°20

Re: RDT (Reverse Draw Technology) crossbow building

by Hermit Mon Apr 07, 2014 8:16 am

Thank you Patandjali,that was the last piece of the puzzle,all that is left to do now,is gather materials,make the cam templates,and build.I am sure I'll come across problems and snags during construction,but thanks to you,I know they can be overcome
Hermit.