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phillysteak527

TAR-21 HPA Gas Drop in Kit

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Before I proceed with this post here is a bit about me:

 

I haven't posted on any other forums on this site other than the WTB/WTS boards. I'm a 23 year old Mechatronics engineer and I currently work as an aerospace engineer. I design hydraulics and control systems for military and civilian aircraft (JSF, A-10, F-16, Boeing 747 to name some of the well known aircraft). I own a small CNC shop and have worked in manufacturing since I was very little.

 

A bit about this project:

 

I am currently working on a drop in replacement for my ARES TAR-21, I love this gun and have fired the RS several times. I just can't stand the performance, I upgraded this gun to be a DMR and found it lacking. I brought it back down to be field legal around me and just hate how finicky it can be at times; So I decided to convert it to run off an HPA rig. I am designing a drop in replacement so if I decide to go back to electric in the future I can. I will list the goals of this project in a moment. But before ya'll go running off telling me that I'm "copying" polarstar.... consider this.

 

I designed this NERF gun 4 years ago in college when I played Humans Vs. Zombies (Don't knock it till you tried it, tag with 1500 people on a college campus with nerf guns is a hell of a lot of fun). It used an open bolt system and ran off of a CO2 rig (Campus police wouldn't let me use HPA):

 

6310162754_0ef81fb8c3_z.jpg

 

More info

 

This NERF gun inspired several people to adapt the bolt to work with airsoft guns, and it was even featured on Hackaday

 

What I am trying to say, is that I was not the first to use this style of actuation, and Polarstar didn't invent it. I just wanted to prove that it existed well before I made that NERF gun, and years before Polarstar came out with their drop in. They make an excellent product, and the selectable open/closed bolt is very useful. However I don't feel like spending about 1000 dollars on building a setup. I only spent 1200 on a RS match grade M1A with a immaculate maple stock for crying out loud..... and building your own stuff is half the fun!!

 

 

 

 

Now for the good stuff:

 

Goals for this project are as follows.

1. Drop in replacement that requires minimal or no modification to the shell

2. Replace mechanical firing linkages with a drop in circuit board.

3. Ability to lock in semi-only, 500Fps max with .25g bb's

4. Improved hop up or replacement hop up unit

5. consistent and accurate shots.

 

Here is where I need some input:

1. Would anyone on here be interested in this?

2. What style hop up should I look into? Honestly I don't know which hop up unit is the best.

3. Can anyone confirm that the new TAR that just came out has the same gearbox just in plastic?

 

 

Feedback is welcome. Just keep in mind I design hydraulics that operate at a burst pressure of 10,000 Psi, and I've build some pretty complicated stuff (Check my site)

 

 

So this is for real, this isn't a theoretical "is this possible?!?!" post.... this will be built.

 

Here is a render of the progress thus far, I am expecting to make some major changes as I design the upper half to this. If this project works out I might consider designing a GBB version. I'm also working on a bullpup M14 GBBR, that will come after this project.

 

Enjoy!

 

7607332428_549a7be224.jpg

 

Current planned features:

- Over-pressure relief valve to protect solenoid valve

- Selectable semi only lock for DMR

- Open Bolt

- Limited run of kits for ~200

- User adjustable FPS/RPS

- Lighter than stock MechBox

Edited by Phillysteak527

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Wow. If you pull this off, this may be the most impressive build I have ever seen by a single individual.

 

To answer your questions, in order:

 

1. Heck yes!

2. I like G36 hop up units, a dial works better than gears in my opinion, or an AUG hop up, it's basically a G36 hop up without a big feeding tube on the bottom.

3. Are you talking about the S&T Tar-21 CQC Explorer, priced at like $160? If you are, I know it's plastic but I don't think it's the same design as the ARES Tar-21. The new one doesn't have a tension release feature or a QD spring swap feature, which makes the ARES Tar-21 vastly different.

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Wow very nice!

 

 

Is this designed only for the TAR-21? If so, and you're looking to make money off of it I feel you have too limited of a market. For example, the P* can be put in most V2/V3 guns. But I definitely loved my Tavor and if it had a nice drop in HPA kit available I would have considered it.

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Basically it's something like the Kuba T1000

http://kuba-t1000.com/minigun/index.php?ak..._conversion_mod

 

He has ready the design and he released it about a year before P*.

It's a very interesting project. I'll built one to convert a springer Geneth WA2000 to semi automatic.

 

 

Wolf

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I had several conversations with the creator of the Kuba and another style adaptation of this system who reached out to me after I made that NERF gun, essentially all of these systems are a pressure relief valve that just directs the flow out a barrel instead of just venting it to atmosphere. I would like to eventually adapt this system to work with M14 platforms as well, once the mechanics are down it is just a matter of making a different housing. The AUG style hop up has been suggested to me in the past, did you mean something like THIS?.

 

I'm working on this project more for myself and my team as we want to compete in the ACA, and I feel an air drop in kit for any of our guns will be a huge boost for consistency and accuracy. If there is sufficient interest I'd be willing to make a small run, not really looking to make any huge profits. The main reason I haven't purchased a polar star for my RDW is price, my simplified system has a price point of about $200 retail..... Plus I love my Tavor.

 

 

EDIT: I looked into the S&T gearbox, it looks very similar. I'm going to be rapid prototyping my design this weekend to make sure it fits my ARES. I'm probably going to look around and see if there are any broken S&T TAR-21's for sale.

 

 

 

Edited by Phillysteak527

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Little Teaser update:

 

I 3D Printed the lower to check certain fits and make sure I got the mounting points correctly spaced. I need to adjust the position of the main mounting holes, I'm planning to use the CMM at work to get precise measurements. But as you can see, it's starting to shape up nicely.

 

7624315526_f22e4468e8_z.jpg

 

7624316360_e41d72c05d.jpg

 

The gearbox mounts in 3 locations, there are 2 pins that also act as a pivot for the bolt release. The other mount location is in the magazine well, so once I make the adjustments and verify that the lower is mounting properly inside the shell I can get to work on the top half.

 

I really want to get this done before the nice weather vanishes (I live in NY).

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HOLY CANOLE!! That's amazing! I've always wanted to 3d print my plans lol I have some parts I've been draining for a while! Too bad those things are expensive! I wish I was into tar's , after this you should definately make a ak gbb drop in kit for the dboys lol! You really have some talent on 3ds!

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Just wanted to drop a quick update so people don't think this died. I printed the bottom of the prototype to test the fit and found that I needed to adjust the mounting locations. I had to wait until today to get access to the CMM at work but I have much more accurate measurements and will print a new lower once I have time to model the changes.

 

Personally I prefer 5 round burst over 3, but I'm designing the electronics to allow you to lock the gun in semi or choose between semi and either 3/5 round burst or full auto. Right now I'm going to be adding a small keypad to the back of the drop-in, changing settings would be as follows:

 

1. Open back compartment

2. Hold "Program" key

3. Select between semi-only or auto enabled

4. Select between 3 round burst, 5 round burst, and full auto

5. adjust delay POT to change burst/auto firing rate

6. Hold "Program" Key to save changes

 

There will be a series of LED's to give you feedback while you change settings.

 

Any thoughts.

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Just wanted to drop a quick update so people don't think this died. I printed the bottom of the prototype to test the fit and found that I needed to adjust the mounting locations. I had to wait until today to get access to the CMM at work but I have much more accurate measurements and will print a new lower once I have time to model the changes.

 

Personally I prefer 5 round burst over 3, but I'm designing the electronics to allow you to lock the gun in semi or choose between semi and either 3/5 round burst or full auto. Right now I'm going to be adding a small keypad to the back of the drop-in, changing settings would be as follows:

 

1. Open back compartment

2. Hold "Program" key

3. Select between semi-only or auto enabled

4. Select between 3 round burst, 5 round burst, and full auto

5. adjust delay POT to change burst/auto firing rate

6. Hold "Program" Key to save changes

 

There will be a series of LED's to give you feedback while you change settings.

 

Any thoughts.

 

Right on man, sounds like a gem, id pick one up off of you any day, if you wanted to stretch it you could do a double tap design, (pull trigger back, one shot, release trigger, one shot, I think that would be cool but complicated but id buy it how it is !:)

 

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Right on man, sounds like a gem, id pick one up off of you any day, if you wanted to stretch it you could do a double tap design, (pull trigger back, one shot, release trigger, one shot, I think that would be cool but complicated but id buy it how it is !:)

 

That's actually not complicated to implement electronically. I've always just had reservations with that style, I used to play paintball and there were numerous accidents that occurred when the player forgot that the gun would fire when they released the trigger. I think for safety purposes it should be left out.

 

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This is very cool, I will have a Solenoid custom by Ninja Turtle by the 9th, I would be interested to see how the two compare!

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If you can honestly hit your $200 goal for an engine for the TAR-21, sign me up. I loved my Ares Tavor, but gearbox headaches made me sell it. If you can get your kit at 200, I won't be able to resist!

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I'll be manufacturing them myself, so I know I can keep that price point. I'm honestly not looking to make a load of cash, I really just want a rock solid and accurate platform and I'm sure I'm not alone.

 

I have a basic parts list together with all the seals I'll be using and the materials. Moving into a new apartment in three weeks so I haven't had too much time to work on this. I'm going to be working with a new airsoft field that opened up near me so once this is ready I'll be able to test it. Once it's ready they can sell TAR-21's with the complete kit pre-installed.

 

 

 

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I'll be manufacturing them myself, so I know I can keep that price point. I'm honestly not looking to make a load of cash, I really just want a rock solid and accurate platform and I'm sure I'm not alone.

 

I have a basic parts list together with all the seals I'll be using and the materials. Moving into a new apartment in three weeks so I haven't had too much time to work on this. I'm going to be working with a new airsoft field that opened up near me so once this is ready I'll be able to test it. Once it's ready they can sell TAR-21's with the complete kit pre-installed.

 

I am game to do that for my tar, getting the kit from you. I was personally also working on converting my Tar over to HPA just for consistency. I love my gun out of all the ones I own minus my HPA sniper.

I have been just running into find a some place to get the parts machined.

 

Now I have done a few modifications to my Tar to eliminate a few issues I faced one was the trigger system.

Fix:I actually installed an electronic switch right in front of the trigger itself using the small firewall as a mounting brace for it.

Then running the wires down the in side of the tar to the back and they fit as if the where suppose too.

So crappy momentary Off/On switch removed

Quirk: it is semi or full auto depending on how hard you pull the trigger. Quick taps are semi and longer pulls are full auto the hard the pull the faster rate of fire.

Fix I haven't done: Install a button in the GB so when the semi is selected the button is pressed causing it to run threw an IC for a single shot\3 round burst

 

I do have to say it is a beast for CQB with that setup. And it is the smoothest trigger pull you will ever feel.

 

Next fix was the hopup:

Fix:Took a madbul Hopup that works horribly and cut the lower part off so it sits flush with the base of the inside body. Next changed out the Air nossle and tappet plate to allow for the longer reach.

Result:works consistently with no quirks. And the Madbul hop up actually works and works good?? also side note used a flat top concept for the hop nub

 

 

Suggestions for the Adjustment board on the left hand side of the Tar opposite side of the bolt catch you have that metal bracket. Why not cut it out and mount a screen and button there for quick easy adjustments. and the board connections can be the flat ribbon connectors that touch the GB. so you can remove the GB or the bracket with out dealing with wires. I will find a pic and correct name later on. with an example I am about to fall asleep on the keyboard.

 

now where exactly will be the quick disconnect be located? Allowing for both left and right hand shooting.

 

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Update:

 

I've been packing all week and haven't had too much time to work on this project. I finally got my new O-ring handbook in from Parker to size all my O-rings correctly. I also printed the V2 housing and the two main mounts are dead on, need to tweak the two small mounts that screw into the mag-well as they are slightly off.

 

If anyone reading this has an HPA rig, what PSI do you run at to achieve around 350 FPS with .2g's? I'm designing the piston to optimize air efficiency with the TAR barrel length so I just wanted a baseline pressure to work around.

 

 

Until next time!!

 

7921692298_b54a5a3282.jpg

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So I know that this thread is literally 4 years old, but I've been running with my Umarex Tavor for the past 4 years, and was wondering if you had any of these conversion kits still. I'm a diehard Tavor fan, no other gun feels comfortable to me to be honest. I play primarily CQB right now; I don't have an outdoor kit really built yet, but I would really love to have my tavor converted to HPA. If by any chance you read this, please reply! I would love to purchase one of these conversion kits from you. If you don't make them anymore, do you know of anyone else who does?

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