New Recoiler Unit

[SoCalBobS]

Recently I was given the opportunity to test and review a servo operated barrel recoil unit by a local company, the "Recoiler Mod B-1" by JVM3Dconcepts. It's a 3DP item, made of high strength resin, designed to fit in Heng Long tank turrets. It allows the barrel to snap back upon firing and to slowly return to battery. It replaces the stock Airsoft gun, so one can't fire pellets anymore.

[MrChef]

Interesting.

Are the dimensions similar, smaller or larger than the current Heng long units?

Is there a spot to mod or cutout in the unit to fit a flash and smoke unit or LED for IR battle?

[SoCalBobS]

Form follows Function:

The Mod B-1 is similar to the Clark recoil unit, which makes sense as it has to fit into the same space. The Mod B-1 handles the recoil, while the tank's elevation function is retained by the motor system. It can be run by the side type motor that connects to the side groove, or the rear type motor that pushes the tab sticking out of the back of the unit. On the B-1, this can be omitted if not needed. A positive feature of the B-1 is the versatility of the servo mount. The servo can be mounted with the gear towards the front or rear as desired, and the gear wheel can be mounted in different ways to the servo. This was helpful when I had to change servos at one point. Each brand has a slightly different shape!

[SoCalBobS]

How to put it in:

So how easy is it? If you've installed units like this before you can skip over the next. I put mine in a Sherman turret that will eventually be part of a Kelly's Heroes Sherman modification. (JVM has tested it in a number of HL and TD tanks.)

Here's the starting point, with the turret bottom removed showing the Airsoft unit and the side motor I mentioned earlier.


I've removed the gun/mantlet/barrel assembly from the turret.


Remove the mantlet from the airsoft gun. The barrel will then slide out from the back of the mantlet.


Put the barrel back in the mantlet, attach the B-1 to the mantlet, and snap the unit beck into the turret. Make sure the side motor is mated correctly to the B-1.

[SoCalBobS]

My opinion? Very positive. This is a prototype and based on some suggestions will have a couple of changes in the next version. This one fits well and works as desired. JVM3Dconcepts is a small batch enterprise run by experienced hobbyists. When the final version of this unit is ready, it will available on Rich Johnson's website, RichardSJohnson.net.

A closeup view of the installation:

[SoCalBobS]

Interesting.

Are the dimensions similar, smaller or larger than the current Heng long units?

Is there a spot to mod or cutout in the unit to fit a flash and smoke unit or LED for IR battle?

Follow-on photos show relative sizes. The slide is hollow, so running wires through it is very easy. Whatever fits in the barrel, fits in the recoiler.

[RichJohnson]

Thank you for this awesome demo and tutorial Bob, you saved me all the work of doing the same thing.
As Bob said they will be on my website very soon.

[Rubicon99]

Interesting.

Are the dimensions similar, smaller or larger than the current Heng long units?

Is there a spot to mod or cutout in the unit to fit a flash and smoke unit or LED for IR battle?

I got a sample too. JVM3Dconcepts attended the San Diego tank clubs June 2023 battle day and had a lot of goodies they asked us to look at and give our input/feedback on. And yes it is more streamlined then the stock HL gun and can easily accommodate all the accessories mentioned.

[Operator7G]

This looks pretty cool. I'll be interested to see an example with the barrel flash/smoke.

[Rubicon99]

This looks pretty cool. I'll be interested to see an example with the barrel flash/smoke.

Flash and smoke are not part of any aftermarket recoil system nor are they part of the metal upgrade HL servo recoil systems. Flash and smoke are stand alone feature that run wires / tube through the barrel. The Mod B1 is designed with a full length shuttle and internal "bore" larger then the stock HL barrels bore so adding flash and the associated wires is super easy because there is more room. Much more then on any other servo recoil of this type.

[Operator7G]

Thanks for the clarification, in which case I look forward to someone eventually doing all that with the Mod B1. :-)

[Zippersnapper]

The Mod B1 is designed with a full length shuttle and internal "bore" larger then the stock HL barrels bore so adding flash and the associated wires is super easy because there is more room. Much more then on any other servo recoil of this type.

As we know the HL recoiling barrel assembly has a smaller diameter "shuttle" that the actual barrel slides on. Is it safe to assume this universal recoiling assembly would allow ANY tank barrel to ride on it, if it were removed from a stock mantlet ? In other words, tanks that dont come with a BB recoiling unit ? You say the "bore" is bigger, but will any tank barrel fit over the shuttle?

inquiring minds want to know.....more....

[Rubicon99]

As we know the HL recoiling barrel assembly has a smaller diameter "shuttle" that the actual barrel slides on. Is it safe to assume this universal recoiling assembly would allow ANY tank barrel to ride on it, if it were removed from a stock mantlet ? In other words, tanks that dont come with a BB recoiling unit ? You say the "bore" is bigger, but will any tank barrel fit over the shuttle?

inquiring minds want to know.....more....

Only HL and TD barrels are direct drop in. BUT other aftermarket barrels can be modified to fit. For instants a Tamiya Pershing barrel is not a direct drop in, but with a simple brass extension tube attached to its rear it can be made to fit. No different then what other types of aftermarket recoil systems need done to fit a variety of aftermarket barrels.

Shown below is a HL Panther barrel laying between the Mod B1 and recoil "barrel shuttle" and then installed in the shuttle.



This photo is of a HL M4 barrel.




HL M4 barrel "in battery"

HL M4 barrel "out of battery" aka max recoil position. This is just an exaggerated example not how it should actually recoils in the tank.


Here are a few of the "breach" section of the Mod-B1 recoil unit.

"Shuttle" bore is 8.44mm wide and runs the entire length of the shuttle. Mine is the "extreme duty" version note the spiral cuts on the shuttle. These are added for self cleaning if you run the unit dry or can be used to hold extra ceramic grease or other lube for those that want to run the shuttle "wet". I will be running the unit dry because it is rather slick already and the added cleaning benefits are useful to me given the dusty conditions I drive my tanks in often.

[Zippersnapper]

Thanx. I was confused with what your calling the "Shuttle". I see now.

[bntix]

It’s a great design. Do you know how to buy the design? Doesn’t make sense to ship from US to Vietnam. Shipping cost gonna more than the item itself.

[Rubicon99]

It’s a great design. Do you know how to buy the design? Doesn’t make sense to ship from US to Vietnam. Shipping cost gonna more than the item itself.

They are made for RichJohnson Models & stuff by JVM3Dconcepts. Check with Rich and see what he can do for you on shipping cost. Maybe if you buy them in some sort of "bulk" amount you can get a good price that would off set the shipping cost.

[tank_me]

I think he wanted to buy the STL so he could print them locally. I fully understand not wanting to sell just the STL though.

[bntix]

Yeah, thanks guys for your feedback. I contacted Richard on instagram. He doesn’t sell STL file. If I buy a batch of 10 then the shipping cost start making sense. But 10 just simply too much. I will just need to deal with existing design I bought from Cults3D or hope somebody will work on this design and sell it on Cults3D/other platforms later. Thanks all ;-)

[DavidN]

My friend in the RC Irvine Tank Club made this unit. I gave me 1 to test-run it. It works. We will be able to keep our HL 7.0 boards after all and have the barrel recoil units for our tanks. I haven't tried on the 6.0 board yet. I will install this unit into a tank this week to see the result.

[Rubicon99]

My friend in the RC Irvine Tank Club made this unit. I gave me 1 to test-run it. It works. We will be able to keep our HL 7.0 boards after all and have the barrel recoil units for our tanks. I haven't tried on the 6.0 board yet. I will install this unit into a tank this week to see the result.

That is a complex design for a servo recoil. The small eMax servos are not known for handling torque loads well. So pulling against a spring and moving the weight and friction of the barrel repeatedly is asking a lot of a small servo. It also looks like he modified the servo wires from three to two. Not sure that will go over well with the Emax servo or other servos over time and use. Is it going to be supplied with the modified servo?

If you are trying to achieve servo recoil with the 7.0 MFU you may not know this, but there is a product made that allows the 7.0 MFU to be used with a servo. There is a thread about it somewhere on this forum. From what I remember it's cheap and largely plug and play simple and does not require modifications to the servo lines.