F-Tr Rig

Get or give advice on equipment, reloading and other technical issues.

Moderator: Mod

Message
Author
Azzopardi
Posts: 39
Joined: Mon Aug 08, 2016 1:32 pm
Location: Cairns, QLD

F-Tr Rig

#1 Postby Azzopardi » Thu Nov 12, 2020 9:33 pm

Setting up another Ftr rig. I have a Joy Pod and have had success. Tried an Oz-pod but prefer the Joy Pod due to its versatility.

Is there a bi-pod that is more joyful than the Oz-pod and more lighter that the Joy Pod?
Regards,
Azzo

Azzopardi
Posts: 39
Joined: Mon Aug 08, 2016 1:32 pm
Location: Cairns, QLD

Re: F-Tr Rig

#2 Postby Azzopardi » Thu Nov 12, 2020 9:46 pm

“More lighter”. Englosh wasn’t my first language while I was wagging school.
Regards,
Azzo

tachyon
Posts: 35
Joined: Mon Jul 15, 2019 1:44 pm

Re: F-Tr Rig

#3 Postby tachyon » Fri Nov 13, 2020 8:40 am

A gen 2 joypod is 584g which is already pretty light. The Dolphin AB Bipod is marginally lighter @ 475g https://www.hoptontrading.com.au/ab-bipod and probably the lightest solid bipod around.

Most bipods use a triangular truss design due to the fact this design is inherently stronger than the cantilever design used in the joypod. With a cantilever design, the joints have large leverage forces so need to be substantially heavier. Even with heavier joints you still get a lot more flex in a cantilever design because the load is a bending moment, rather than a compression one.

So, given a coaxial head and control rod must weigh more than a static head of equivalent size if you wanted both more lighter and more joyful you would need to graft the lightweight coax head of a joypod to a lightweight carbon fiber truss.

jasmay
Posts: 1157
Joined: Fri Sep 28, 2012 9:26 pm

Re: F-Tr Rig

#4 Postby jasmay » Fri Nov 13, 2020 12:59 pm

tachyon wrote:A gen 2 joypod is 584g which is already pretty light. The Dolphin AB Bipod is marginally lighter @ 475g https://www.hoptontrading.com.au/ab-bipod and probably the lightest solid bipod around.

Most bipods use a triangular truss design due to the fact this design is inherently stronger than the cantilever design used in the joypod. With a cantilever design, the joints have large leverage forces so need to be substantially heavier. Even with heavier joints you still get a lot more flex in a cantilever design because the load is a bending moment, rather than a compression one.

So, given a coaxial head and control rod must weigh more than a static head of equivalent size if you wanted both more lighter and more joyful you would need to graft the lightweight coax head of a joypod to a lightweight carbon fiber truss.


Hi Tachhyon, in an effort to understand what you mean by the flex from the “cantilever” could you do a rough sketch pointing out what you mean and share it please?

PeteFox
Posts: 132
Joined: Tue Oct 16, 2018 5:20 pm
Location: Tas.

Re: F-Tr Rig

#5 Postby PeteFox » Fri Nov 13, 2020 1:35 pm

This hypersensitivity about anything said about Joypods is getting more than a bit boring.

The sloping arms of a Joypod are cantilevered off the main vertical columns, much like a portal frame shed. At the top of each column is a brace (knee plate) which resists relative movement between the column and the sloping arm. Remove the brace and the portal frame collapses. These braces have weight.
What is different from a portal frame in a Joypod is that normally the feet are anchored to the ground and the legs are vertical. With a Joypod neither of these may exist depending on the shooting conditions. This calls for a stronger brace - more weight.
If you are going to exert a force on the Joypod it must flex either in the brace, the leg or sloping arm or all three.

Blame Newton
Pete

cheech
Posts: 204
Joined: Wed Jul 15, 2009 11:10 pm

Re: F-Tr Rig

#6 Postby cheech » Fri Nov 13, 2020 2:22 pm

jasmay wrote:
tachyon wrote:A gen 2 joypod is 584g which is already pretty light. The Dolphin AB Bipod is marginally lighter @ 475g https://www.hoptontrading.com.au/ab-bipod and probably the lightest solid bipod around.

Most bipods use a triangular truss design due to the fact this design is inherently stronger than the cantilever design used in the joypod. With a cantilever design, the joints have large leverage forces so need to be substantially heavier. Even with heavier joints you still get a lot more flex in a cantilever design because the load is a bending moment, rather than a compression one.

So, given a coaxial head and control rod must weigh more than a static head of equivalent size if you wanted both more lighter and more joyful you would need to graft the lightweight coax head of a joypod to a lightweight carbon fiber truss.


Hi Tachhyon, in an effort to understand what you mean by the flex from the “cantilever” could you do a rough sketch pointing out what you mean and share it please?


Well I’d really like to know too !

I’ve used 2 Joypods for quite awhile now and “ flex “ doesn’t enter as a word of description for the product , or maybe it’s just me that inspects and services the joypod just like the rest of my expensive gear .

Cheers

tachyon
Posts: 35
Joined: Mon Jul 15, 2019 1:44 pm

Re: F-Tr Rig

#7 Postby tachyon » Fri Nov 13, 2020 2:58 pm

jasmay wrote:
Hi Tachhyon, in an effort to understand what you mean by the flex from the “cantilever” could you do a rough sketch pointing out what you mean and share it please?



Here's the basic engineering - we want to support a weight (W) above the ground.

Screen Shot 2020-11-13 at 3.39.30 pm.png


Assume we Tig welded a couple of bits of alloy tube together at an angle to make the structure top left. As we load it up, we will see it sag and the inside of the tube will be in tension and the outside in compression. That is a basic cantilever beam where it is supported at one end... (shown below that)

A stronger structure for a given weight of material is the truss - you will recognise it from bridges, cranes, and buildings. In the truss shown we have 2 elements in compression and one in tension - often the tension element will be a thin cable.

If you think about aircraft you will note that lightweight is good, that's why all the early aircraft were truss designs with wire bracing. Better materials lead to cantilever wings but anyone who's looked out the window of a jet in a bit of weather will know just how much those cantilever wings flex.
You do not have the required permissions to view the files attached to this post.

Redhawk
Posts: 97
Joined: Thu Mar 16, 2017 9:24 pm

Re: F-Tr Rig

#8 Postby Redhawk » Fri Nov 13, 2020 7:37 pm

“Is there a bi-pod that is more joyful than the Oz-pod and more lighter that the Joy Pod?”

Hi Azzo

I have not found it:) If you do, let me know, and I will give it a go too.

Have tried most of the bipods out there, and each have characteristics I like and dislike. I get back to the joypod every time..... others get back to their favourite, it works for them.

Consistent recoil management is probably more important for me with FTR than any other rifle related issue (yes, before some smart ass comments; reading the conditions is more important). Personally, I have never experienced the “flex”.... my senses might not be sensitive enough.

Regards
Frans
Last edited by Redhawk on Sun Nov 15, 2020 9:32 pm, edited 1 time in total.

Tim L
Posts: 656
Joined: Mon May 19, 2014 7:11 pm
Location: Townsville

Re: F-Tr Rig

#9 Postby Tim L » Fri Nov 13, 2020 7:53 pm

jasmay wrote:
Hi Tachhyon, in an effort to understand what you mean by the flex from the “cantilever” could you do a rough sketch pointing out what you mean and share it please?

Jase, have a gen up on bending moments and 2nd bending moments.
An apex tripod avoids most of these effects due to the recoil torsional force being sent (mostly) straight down the leg. There's a bit left but most of the force is transfered as compression into the LH leg.

In the joypod torque is transfered into the LH rod and then into the leg. This induces a bending moment into the rod which is resisted by the 2nd bending moment of the rod (tubes are not ideal as you will see from the maths. Bending moments are dependent on the cross sectional area of the material at 90 degrees to the moment. (Think I beam, the thick vertical determines the bending moment, the top and bottom bit are only there to stop it twisting and transitional bending in the other plane.) 2nd bending moments are dependent on the cross sectional area of the material in the tube and the tube length). From here mechanics comes into play. The tube does bend, then it straightens sending forces into the RH tube, this also bends and straightens.
I have high speed video of my Joypod in recoil, the RH leg is actually about 1/2" off the front mat as the rifle moves backwards.

Is this an issue? No! The bullet left long ago. It can also be managed by stock design and using the front mat/bag to absorb most of these forces.

That said Seb could minimse the effects through design (which I'm sure he knows). Look at how the Mpod and the AB bipod drop the rifle so the torque axis (barrel bore) drives directly into the leg rather than sitting above. This has the effect of sending more of the torque sideways. Chris could do this with the Auspod too, but at what cost to manufacture, and for what gain given the bullet has gone before any of this happens?

Rich4
Posts: 290
Joined: Sun Feb 24, 2019 2:33 pm
Location: Chinchilla

Re: F-Tr Rig

#10 Postby Rich4 » Fri Nov 13, 2020 9:55 pm

Azzopardi wrote:“More lighter”. Englosh wasn’t my first language while I was wagging school.

I know plenty of people, myself included! Who struggle to speak understandable english as a first language :lol:

Tim L
Posts: 656
Joined: Mon May 19, 2014 7:11 pm
Location: Townsville

Re: F-Tr Rig

#11 Postby Tim L » Fri Nov 13, 2020 10:26 pm

Rich4 wrote:
Azzopardi wrote:“More lighter”. Englosh wasn’t my first language while I was wagging school.

I know plenty of people, myself included! Who struggle to speak understandable english as a first language :lol:

The whole point of language is to communicate and there's no one who won't understant what " more lighter" means. Those that want to pick holes are just arseholes ( or good friends just taking the piss). Either way f**k 'em
Btw azzo you have the best two pods I've come across so if u can't make one of 'em work stick to Open and your belly bench rest stylie.

superx10
Posts: 131
Joined: Wed Aug 19, 2015 9:32 am

Re: F-Tr Rig

#12 Postby superx10 » Sat Nov 14, 2020 6:00 am

Hi Azzo I have used and owned both the joypod and the ozpod. The joypod is like all seb products very well made and functions well and is probably on most of the winning FTR rifles, that said I found it a pain to set up on the mound for the big adjustments and currently see the users doing all sorts of body twists to look down the scope to get the scope centered, thats why I change to the ozpod and am finding it works well if used as Pommy Chris details in the instructions, it much more agricultural in appearance and operation but suits me.

The big kicker is the OZ POD IS HALF THE PRICE OF THE jOIYPOD.

The perfect FTR front rest, in my opinion, would be a design incorporating the good characteristics of both the joypod and the ozpod
I have not seen one yet.

Is there a top FTR shooter in Brisbane making one?

Quick
Posts: 1067
Joined: Fri Aug 15, 2008 9:09 pm
Location: Yanchep, Western Australia
Contact:

Re: F-Tr Rig

#13 Postby Quick » Sat Nov 14, 2020 6:59 am

I used a Joypod for 2 years. Had a rifle that shot nearly as well as my FO rig. I never experience flex until I had raised the bipod to close its max height. If your doing that I think your setup is wrong and you need to re-evaluate your mound setup or perhaps rifle stock design. Most of the time I didnt have it set higher then probably 1.5in higher then bottomed out. Correct front mat and rear bag choice and amount of packers used will alleviate that issue.

The biggest issues Ive seen in F/TR is that many people DONT look at their total mound setup and optimise it to work best. They arnt willing or dont know that they need to fine tune certain things to get it all working right.

I think for F/TR a Joypod is the best, having that joypod adjustment is so useful that it makes up for alot. Ive tried the PCW, Auspod, Rempel, etc and the fact that you have to move the bipod legs side to side just ruins the tracking and recoil management of the whole system which harms consistancy.

But Im back to being a belly benchrester now so make of it what you will.... :D
Shaun aka 'Quick'
Yanchep, Western Australia

308 Win F/TR & F-S
7mm F-Open Shooter.

jasmay
Posts: 1157
Joined: Fri Sep 28, 2012 9:26 pm

Re: F-Tr Rig

#14 Postby jasmay » Sat Nov 14, 2020 7:40 am

I used to make my Own carbon fiber “truss” style bipods when i starred shooting F-Class, I tried pretty much all the name brand bipods looking for one that didn’t have an issue.

I made several versions with different parts, my bug bear with most all of them was play in the threads for adjusting height, as has been mentioned in another thread, one in question
requires its last movement to be in a direction so the slop is not in a the down direction otherwise you get thrown shots, meaning each time you make an adjustment, you have to go past the point of aim and come back to it taking the play out.

Even bipods like the Phoenix publish on their website that the gear design “virtually eliminates creep down” yet it doesn’t entirely eliminate it....

The other issues with the traditional non geared style is torque will eventually (and in some I have used after each shot) cause the bipod to cant the rifle, and we all know how detrimental a canted rifle can be at long range, which means employing a level bubble and monitoring it religiously after each shot.

No bipod is perfect, but some are close, as Shaun pointed out, a good overall setup is what makes things work, I know he spent a long time working on that after he understood the need, he then won almost any comp he entered until others around him caught up.

Personally, I think most all the bipods that have been mentioned on this forum over the last few weeks are all up to the task of delivering amazing scores IF USED CORRECTLY AND IN CONJUNCTION WITH A WELL DESIGNED OVERALL SETUP.

some of the comments I have seen just kind of make me laugh, it’s the old adage, shooters will always blame their gear for a bad score before they blame themselves and what they are doing wrong.

I’ve seen hundreds (and shot a few myself) 60.10’s and perfect scores around the globe shot from most all bipods mentioned here, if you can do that, I highly doubt there is an inherent engineering flaw in a bipod that is destroying your ability to shoot.
Last edited by jasmay on Sat Nov 14, 2020 9:00 am, edited 1 time in total.

williada
Posts: 953
Joined: Wed Jul 22, 2009 12:37 am

Re: F-Tr Rig

#15 Postby williada » Sat Nov 14, 2020 8:06 am

The flex can be your friend. It depends how it is harvested in the tune and your body position. While the rifle moves a lot after the bullet has left the barrel, momentary forces do impact the harmonics no matter what system is used.


Return to “Equipment & Technical”

Who is online

Users browsing this forum: No registered users and 17 guests