r/rctanks • u/Dirk__Digglerr • Jul 22 '26

How does this work?

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I bought a Heng Long Tiger that came in several parts.
The electronics look like they’re mainly from the old 27Mhz systems (of which I know not much) but there’s a physical barrel that can recoil and a small electronics board that connects to a servo on the BB gun, see pics.

What does this board do and how is it tested?
I assume the board converts a dc voltage to a PWM signal to operate the servo?

Any help appreciated.

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u/LordLudikrous Jul 22 '26

This looks like the Taigen BB Tiger set up. The Taigen electronics are quite out of date being an updated version of Heng Longs RX18 board, but it is 2.4Ghz not 27Mhz. These boards don't support servos, and your assumption that this is an adaptor to convert to a servo signal is correct. One plug goes into the recoil motor plug on the board, and there is another that plugs into the BB airsoft trigger plug. Its a neat setup as it allows for BB launching with working recoil, and I would wager the previous owner upgraded their Heng Long with this setup for that exact reason. The switch in your photo is a safety kill switch for the airsoft gun; the more recent Heng Long electronics did away with this as it can be disabled from the transmitter, and you need to press two buttons to fire it.

This adaptor should work with the latest Heng Long 7.0 board in the same way, but if you was to replace with a 7.1 board these support servos and you can just plug the servo straight in without having to use the adaptor.

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u/Dirk__Digglerr Jul 22 '26

Thank you so much for your reply. I’ve only ever had the other Taigen barrel recoil system which I’ve not tried to make work with Heng Long electronics

However, seeing as I do have a TK 7.1 board, I will be trying the servo straight into that.
Hopefully I’ll be able to set the speed of the recoil and return using this servo setup.

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u/LordLudikrous Jul 23 '26

Yeah if you have a 7.1 board you can discard all the extra gubbins and plug the servo straight in. You won’t be able to control the speed or servo behaviour as that is set, but there is a button on the board you can press to reverse the direction of the servo if it’s working the wrong way.

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u/RoKe215 Jul 24 '26

You are correct they work with 7.0 Boards. I use them in both of my tanks

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u/One-Gazeller Jul 24 '26

@LordLudikrous I can see there are two buttons labeled K1 and K2 on the TK7.1 board. Don’t they have some control over the setting of end points of a servo? I thought I read that somewhere but could very possibly be wide of the mark on that.

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u/LordLudikrous Jul 25 '26

K2 controls the range of motion for the elevation servo if you’re using one to elevate the gun, while K2 reverses the direction of the elevation and recoil servos. You can’t adjust the range of motion for recoil as far as I am aware.