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Old 03-29-2020, 11:44 PM   #46
Behslayer
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Re: Made a 145cm inverter, 10mm shaft

Look at the Handle. That's where the drop is.
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Old 03-30-2020, 12:09 AM   #47
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by Behslayer View Post
Look at the Handle. That's where the drop is.
It is just the gun kicking up with the recoil, the muzzle is going up and the handle is going down, check out the full sequence.

Maximum force is when the sear tooth lets go, the spear tail exits the sear box and the forces begin to fall as the bands contract. The wishbone cable is pushing the muzzle rollers back as the bands pull on the cable. The bands are also pulling on the cable anchor, but that is not going anywhere being part of the gun body.
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Old 03-30-2020, 12:51 AM   #48
popgun pete
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Re: Made a 145cm inverter, 10mm shaft

One way to look at it better would be to make a short video loop of the actual shots from this angle and compare them. I have just done the shot at 2.35 seconds.
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Old 03-30-2020, 02:25 AM   #49
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by Behslayer View Post
Hi Paul,

Firstly congratulations on some of the incredible captures. It's too bad we never cross paths. I think I left Bali before you moved there?

It was the tail lift and shaft whip I noticed in the 0.25 playback, but as you say, you still hit the target. Does it make sense to use an enclosed track for the first 1/3 of the gun?

Would you share some dimensions of that gun?

Hope you are okay over there. There is no news of Indonesia regarding Corona Virus, but my friends from Bali are saying things are not great.
Hi Jon, Yes, I think you had left Bali when I moved there. I'm in Aberdeen Scotland, I few here just before the flights stopped. I hear Bali is super quiet.

This gun is very accurate, even though the is shaft is lifting. I believe this is because the gun has zero flex. The shaft is pushed back into the track as the wishbone leaves the stopper tube and leaves the gun flat. I would like to try a 11mm shaft but no idea where to buy one.
When you shoot this gun, your first thoughts is. it doesn't feel like it has much power as there is very little recoil from this gun. The recoil is smooth, if that makes sense.
I will try and find better side view video, I know in that video it looks like the shaft is down a bit, but the shaft is very flat in flight.

I have made some video's testing 3 & 4 band classic guns, theses video's showed both set ups had shaft lift. I believe most powerful classic guns will have shaft lift. But yet to prove this theory. I'm sure Majd could correct me on this theory with all the testing Majd has done.

Andre did make a inclosed track roller gun, the shaft was splitting the wood where the shaft was exiting the end of the inclosed track. Andre doesn't make inclose track roller & inverter guns anymore.
My thinking with a inclose track, is there to much force been pushed up and which will course poor performance, but I have never tested a inclose track gun.

The gun is quite big size to float the heavy shaft and the three & half raps 1.6mm cable (total length 11.2 meters). I will attach dimensions of the gun.
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Last edited by Satdiver; 03-30-2020 at 04:36 AM.
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Old 03-30-2020, 02:33 AM   #50
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Re: Made a 145cm inverter, 10mm shaft

Some more dimensions. Each delrin roller have 2 ceramic bearings in each. The bearings make it easer to load the gun. Also its very importing to have low shark fins and the correct angle for the wishbone. Also the placement of the shark fin the shooting line is crimped to.
I make everything on the gun except the Ermes trigger, ceramic bearing and 316 stainless inserts.
I have to say Ermes new genatration trigger's is big improvement to Mario's older model's.
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Old 03-30-2020, 02:49 AM   #51
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by popgun pete View Post
The initial tail lift of the shaft may be due to the use of shaft tabs as the spear is moved by an off-axis force compared to its centerline. One way to check that out would be to use for experimental purposes a wishbone slotted shaft instead. The inverted rollergun with a single wishbone has a lot of force just on one tab, whereas a multi-band traditional gun has the force spread out over two or three tabs and the slight downward angled pull of all the bands via their wishbones may serve to clamp the shaft back onto the barrel track.
Hi Pete, I did think this, I welded a fin on a hunt shaft on the milled flat that goes into the trigger. Still have shaft lift. But I don't think there is a problem with the shaft lifting, As I still get very good accuracy and penetration with minimal recoil.
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Old 03-30-2020, 03:01 AM   #52
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by popgun pete View Post
It is just the gun kicking up with the recoil, the muzzle is going up and the handle is going down, check out the full sequence.

Maximum force is when the sear tooth lets go, the spear tail exits the sear box and the forces begin to fall as the bands contract. The wishbone cable is pushing the muzzle rollers back as the bands pull on the cable. The bands are also pulling on the cable anchor, but that is not going anywhere being part of the gun body.
I believe you are correct Pete, I make my front roller slots as far forward on the gun as possible, so the shaft has left the gun before the recoil lifts the front of the gun.
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Old 03-30-2020, 03:40 AM   #53
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Re: Made a 145cm inverter, 10mm shaft

Great job Paul ... really made huge improvements! Looks like that gun is very controllable and has lots of power. I think this gun needs to be compared to how an Alemmani Vela 135 shoots and from the video it certainly seems like you sorted out a lot of the problems there. Congrats!

Low shooting is really very hard to control with rollers, especially once you start ramping up the power on lighter shafts ... for some reason the tail lifts and causes low shots. I mentioned that way back a few years ago but got flamed and trolled endlessly for just trying to point out facts and hoping those problems could be worked on. In this case I think Paul really did a good job with tail lift and if you compare a side by side comparison with say an Alemmani Vela 135, you will see a huge improvement in that area. I am still not sure why tail lift is such a problem with rollers, but a lot of people are just getting used to the gun shooting lower and somehow adjust aim ... or reduce the power by 30% and accept that (that is what I do if I have to use a roller gun). Of course with tail lift ... low shooting is not the only problem ... it also means that the shaft is unstable and thus you will not get optimal performance as an unstable shaft sheds velocity a lot quicker and of course accuracy is not the same. However at hunting distances maybe the compromise of a little lower shot is worth it to gain less recoil for some.

I think the way to really improve things with rollers is to test with light shafts ... say a 7mm to 8mm shaft. A thick stiff shaft masks a lot of problems. That is what I did when I was trying to control shaft stability with classic guns. Tail lift is also a huge problem with classic guns and many guns also have problems with that. Initially in testing the max I was able to control at full power was a 145cm shaft @ 7mm .... anything longer and shaft whip was a problem. But 2 years later I was able to control even a 165cm @ 6.7mm shaft with full stability. With rollers a lot more stuff is happening ... but I think the handle is also an important factor ... however you also need to check roller height, wishbone stop location and also the location of where you attach your wishbone on the shaft seems to be an important factor. Progress usually comes in small increments where you look honestly at the test data and then adjust accordingly and test again.

Last edited by spearq8; 03-30-2020 at 03:54 AM.
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Old 03-30-2020, 03:58 AM   #54
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Re: Made a 145cm inverter, 10mm shaft

One more thing ... the trigger Paul is using is the 2nd generation trigger from Ermessub. This looks pretty much the same as the older trigger but is completely different in almost every aspect. These trigger boxes are bent on custom made molds that allow you to cut the lateral holes while in the mold ... this makes the axle pins of the trigger sear and shaft sear perfectly horizontal and thus a much better distribution of forces. Also the sears are all now cut using EDM (electro discharge) ... which has a 10x higher tolerance than the best lasers or water jet cutting. The shaft sear is cut from a single block of 316 SS (used to be 3 plates screwed together) ... also the front roller is now around 6mm while earlier versions were 4.3mm .... so much larger surface area for the front roller ... which means much better handling of higher loads. All pins are now CNC machined to get a perfect tolerance between shaft and trigger sear holes with the pin and for the sear pins they have moved up from 4mm to 5mm ... this allows perfect rotation. The front of the mech box now has a special spacer which is held in by 2 screws ... this spacer allows for perfect inner dimensions of the trigger box even if the wood of the gun swells and presses on the sides of the mech box. Another improvement is the line release ... lot of work went into getting the highest aperture opening of the line release ... if I remember correctly it is 65 degrees (older trigger was about 42 degrees) ... I found out that on many triggers if the line release doesn't open fully, it drags the shooting line and this causes a small loss of accuracy as the line gets tugged. Of course the line release auto reset has been totally fixed now by using a double rotation sleeve that breaks up the effort for the line release ... this actually was a big problem initially as by increasing the amount of aperture opening of the line release you ended up with a much more difficult auto reset of line release as it had a much longer stroke to reset ... the double rotation spacer fixed this. Many little things but they add up to a huge difference. I might put up a post just on the trigger as I think a lot of progress has been made there. A trigger is the heart of any speargun so it is nice to know that this is one thing you don't have to worry about in your build! Autodesk really did an amazing job with Fusion 360 and allowed hobbiest to use some of the most sophisticated and powerful 3D modeling and 3D simulation and 3D stress analysis software available on earth for free. Many of the new improvements in this trigger were possible because of that. Hats off for Autodesk for doing that!
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Old 03-30-2020, 06:27 AM   #55
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Re: Made a 145cm inverter, 10mm shaft

Eurogun models which you shoot with one hand, and maybe two if you cup one hand over the other, will always lift unless the gun is heavily ballasted in which case it will not really be a eurogun. Your wrists just cannot control the gun if it tilts upwards with a lot of energy stored in the gun to blast out a heavy shaft. Cocking stock guns and their counterpart rear handle biased mid-handle guns allow an opposing torque to be applied to the rear of the gun with your other hand because the rearward projection of the gun offers a lever arm to push against. What has helped inverted rollerguns is a paddle like forward stock and this could be further augmented by lateral blades, but then the gun will handle like an oar, therefore there is a limit to using drag to suppress muzzle lift.

If the gun works and does its job then there is no need to push the boundaries ever further and guys have been shooting fish for more than half a century with reasonably simple guns. The inverted rollergun has extended the ability of the eurogun up to a level which otherwise it may not have attained by cramming more rubber onto the gun.

One of the more powerful euroguns of the distant past was the nearly 2 meter long Champion Requiem, but that gun had a forward handle as well as the usual grip handle at the rear. Another would be the Sampson Long Tom, but it had a poor trigger mechanism that loaded up with strong bands, so it had to make do with three band sets. Not too many want to swim with a 2 meter long gun, so those guns have disappeared.

Last edited by popgun pete; 03-30-2020 at 02:35 PM.
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Old 03-30-2020, 06:35 AM   #56
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by spearq8 View Post
One more thing ... the trigger Paul is using is the 2nd generation trigger from Ermessub. This looks pretty much the same as the older trigger but is completely different in almost every aspect. These trigger boxes are bent on custom made molds that allow you to cut the lateral holes while in the mold ... this makes the axle pins of the trigger sear and shaft sear perfectly horizontal and thus a much better distribution of forces. Also the sears are all now cut using EDM (electro discharge) ... which has a 10x higher tolerance than the best lasers or water jet cutting. The shaft sear is cut from a single block of 316 SS (used to be 3 plates screwed together) ... also the front roller is now around 6mm while earlier versions were 4.3mm .... so much larger surface area for the front roller ... which means much better handling of higher loads. All pins are now CNC machined to get a perfect tolerance between shaft and trigger sear holes with the pin and for the sear pins they have moved up from 4mm to 5mm ... this allows perfect rotation. The front of the mech box now has a special spacer which is held in by 2 screws ... this spacer allows for perfect inner dimensions of the trigger box even if the wood of the gun swells and presses on the sides of the mech box. Another improvement is the line release ... lot of work went into getting the highest aperture opening of the line release ... if I remember correctly it is 65 degrees (older trigger was about 42 degrees) ... I found out that on many triggers if the line release doesn't open fully, it drags the shooting line and this causes a small loss of accuracy as the line gets tugged. Of course the line release auto reset has been totally fixed now by using a double rotation sleeve that breaks up the effort for the line release ... this actually was a big problem initially as by increasing the amount of aperture opening of the line release you ended up with a much more difficult auto reset of line release as it had a much longer stroke to reset ... the double rotation spacer fixed this. Many little things but they add up to a huge difference. I might put up a post just on the trigger as I think a lot of progress has been made there. A trigger is the heart of any speargun so it is nice to know that this is one thing you don't have to worry about in your build! Autodesk really did an amazing job with Fusion 360 and allowed hobbiest to use some of the most sophisticated and powerful 3D modeling and 3D simulation and 3D stress analysis software available on earth for free. Many of the new improvements in this trigger were possible because of that. Hats off for Autodesk for doing that!
Hi Majd, I have used Mario's older design triggers previously in my guns, the new design is great improvement. The trigger is very smooth to load with the line release in both the forward or in the rear position. Also very crisp and smooth to fire with the heavy load I have on this gun.
I have uploaded a video showing how smooth Mario's trigger is to load with the line release in different positions.

https://youtu.be/-NsLV4uCI0k

Last edited by Satdiver; 03-30-2020 at 06:53 AM.
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Old 03-30-2020, 07:19 AM   #57
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Re: Made a 145cm inverter, 10mm shaft

New Ermes trigger works fine. Especially long version is very smooth, but long version is not suitable for eurostyle guns with high positioned handle because rear screw goes outside the handle.
So I ordered from Mario custom trigger rotated backward, and plan to shorten trigger housing.
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Old 03-30-2020, 07:48 AM   #58
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by gspearguns View Post
New Ermes trigger works fine. Especially long version is very smooth, but long version is not suitable for eurostyle guns with high positioned handle because rear screw goes outside the handle.
So I ordered from Mario custom trigger rotated backward, and plan to shorten trigger housing.
Hi Neven, Sounds very interesting project, be good to see how the trigger looks installed in your gun.
I'm always impressed with the quality of your work, I know how hard it is to router accurately the trigger pocket, you take it to another level with using epoxy and graphite and leaving 1mm. Amazing accuracy and quality work.
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Old 03-30-2020, 07:54 AM   #59
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Re: Made a 145cm inverter, 10mm shaft

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Originally Posted by Satdiver View Post
Hi Neven, Sounds very interesting project, be good to see how the trigger looks installed in your gun.
I'm always impressed with the quality of your work, I know how hard it is to router accurately the trigger pocket, you take it to another level with using epoxy and graphite and leaving 1mm. Amazing accuracy and quality work.
Thx Paul! Your work is getting better and better. I hope chats we used to have helped at least a little.
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Old 03-30-2020, 09:48 AM   #60
Satdiver
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Re: Made a 145cm inverter, 10mm shaft

Quote:
Originally Posted by spearq8 View Post
Great job Paul ... really made huge improvements! Looks like that gun is very controllable and has lots of power. I think this gun needs to be compared to how an Alemmani Vela 135 shoots and from the video it certainly seems like you sorted out a lot of the problems there. Congrats!

Low shooting is really very hard to control with rollers, especially once you start ramping up the power on lighter shafts ... for some reason the tail lifts and causes low shots. I mentioned that way back a few years ago but got flamed and trolled endlessly for just trying to point out facts and hoping those problems could be worked on. In this case I think Paul really did a good job with tail lift and if you compare a side by side comparison with say an Alemmani Vela 135, you will see a huge improvement in that area. I am still not sure why tail lift is such a problem with rollers, but a lot of people are just getting used to the gun shooting lower and somehow adjust aim ... or reduce the power by 30% and accept that (that is what I do if I have to use a roller gun). Of course with tail lift ... low shooting is not the only problem ... it also means that the shaft is unstable and thus you will not get optimal performance as an unstable shaft sheds velocity a lot quicker and of course accuracy is not the same. However at hunting distances maybe the compromise of a little lower shot is worth it to gain less recoil for some.

I think the way to really improve things with rollers is to test with light shafts ... say a 7mm to 8mm shaft. A thick stiff shaft masks a lot of problems. That is what I did when I was trying to control shaft stability with classic guns. Tail lift is also a huge problem with classic guns and many guns also have problems with that. Initially in testing the max I was able to control at full power was a 145cm shaft @ 7mm .... anything longer and shaft whip was a problem. But 2 years later I was able to control even a 165cm @ 6.7mm shaft with full stability. With rollers a lot more stuff is happening ... but I think the handle is also an important factor ... however you also need to check roller height, wishbone stop location and also the location of where you attach your wishbone on the shaft seems to be an important factor. Progress usually comes in small increments where you look honestly at the test data and then adjust accordingly and test again.
Hi Majd, Thanks for your complement.
I will try to up load video's of target testing and the shaft lifting with my older model Alemannia Vela, now I have finally worked how to do this.
The new model Vela I have is balanced perfect. This gun will almost float a 10mm Hunt double offset flopper shaft with 8.4mts of 1.6mm cable.
The video's I have of my new Vela are back in Bali on a hard drive.
With the new Vela I was shooting quite high at 6 & 7 meters pool testing, I contacted Alemanni and asking why. Itio told me the gun was underpowered and to cut the bands. I'm still shooting a bit high, so maybe I need to cut more.
Alemanni does not have a track in his guns. I suspect one of the reasons is because of shaft lift and the gun flexing.

Once I get back to Bali, I can do testing with different diameter shafts & compare the Vela to my 145 gun, will be a interesting test. I will try and make a 11mm shaft to test as well. Also can tie rubber at a less percentage and try smaller O/D bands as Neven suggested as well.

I have the front rollers as low as I can get them, also the front rollers as far forward as I can on my 145 inverter.
The bands on my 145 invert weigh's 1.1kg which helps add mass to the gun and reduces recoil.

I have attached photo's of my Alemanni Vela showing shaft lifting.
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Last edited by Satdiver; 03-30-2020 at 01:01 PM.
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