Ultra-Easy Servo Recoil Mod for Heng Long Tanks

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phyrephish
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Ultra-Easy Servo Recoil Mod for Heng Long Tanks

Post by phyrephish » Fri Mar 31, 2017 9:59 pm

Hey All

Everyone knows the Heng Long recoil system in it's factory supplied condition is just horrible. Modifying the recoil to operate properly is not that hard to do but it is a real pain. Plus spring loaded recoil units (Heng Long & Asiatam) snap back quite hard and the micro switch operation can be unreliable and confusing. With that in mind I set about to find a super simple way to mod the Heng Long recoil. The result is a servo controlled recoil system that operates in conjuction with an ATRC MKII circuit. If you can use a saw and drill then you can do this mod. Here it is.....

Step 1. Get your Heng Long Recoil Unit
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Step 2. Unscrew and take apart
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Step 3. Take out all of the insides, motor and gears
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Step 4. With a hobby saw cut off the bottom of the unit along the line as shown.
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The recoil should now look like this.
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Step 5. Take the barrel and unscrew the teeth
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Step 6. Grab a PCB spacer (from old computer)
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Step 7. Screw the spacer into the hole that held the teeth
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Step 8. Grab a servo (We have these servos and servo mounts for sale in the shop but you can use your own)
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Step 9. Postion the mount as shown and screw into place
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Step 10. Attach servo as shown. All that is left is to connect a linkage rod from the servo arm to the PCB spacer. The servo lead is then connected to an ATRC MK II board.
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To be continued....... Well all the hard stuff is done but I'll post the rest of the mod as I get the time.
Cheers...

Nice 2 know Admin.... Now for the rest of the mod.

Firstly, I've missed some important photos that should go here. The shots above show a unit theat will only allow the standard Heng Long amount of travel (which isn't much). Such a mod will only require 45 degrees of servo travel. (the amount that you'll get with an ATRC MKII) To get more travel I have cut the back half off of the piece that moves back and forth inside the unit. Doing so will give you nearly an extra 10mm of recoil and will require about 45 degrees of servo arm rotation.

Step 11. I don't know anyone who hasn't bought and destroyed one of those little RC 'copters or a small RC car. If you have check them out for any small control arms land put them to good use.
Barrel in ready to fire position (RTF)
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Barrel at full recoil (approximately 90 degrees of arm travel)
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Side view
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Next up I guess I should show some video and maybe how to set up your 9X for a beautifully recoiling main gun........

OK here is the video of the recoil mod in action. The servo is being controlled by the Turnigy 9X running tankER9X version of the firmware.



Cheers
KG
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phyrephish
King Tiger Commander
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Posts: 135
Joined: Sun Mar 26, 2017 10:24 am

Re: Ultra-Easy Servo Recoil Mod for Heng Long Tanks

Post by phyrephish » Fri Mar 31, 2017 10:03 pm

Hey All

As stated earlier in this thread this mod can also be done with the BB gun unit as well since the two unit function similarly. However, I have not posted any pics or instructions for the BB gun mod. It is pretty simple and I think many have been able to work it out by themsleves. Regardless, one day I'll get round to it in more depth but till then here are some pics of the BB unit modded for recoil.

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As you can see the BB unit is a bit 'fatter' than the recoil unit. Hence to have the servo arm swing in the centreline of the barrel the servo can be mounted on the bottom of the unit rather than on the side.

You can also see a method of attaching the block inside the BB unit with the barrel. You can use some shrink tube to attach the barrel to the protruding nipple on the block inside. In the pic above the shrink tube is red. Depending on the tank and barrel used you can even cut the shrink tube to a certain length to make fine adjustment of the barrel length.

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Cheers
Kevin G
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