T-REX 470L Tail Ratio Upgrade Kit

(1 customer review)


10 in stock

SKU: KC3D-H470K Categories: ,


T-REX 470L Tail Upgrade kits are back in stock! Get yours now.

Say goodbye to tail kicks and blowouts on your T-REX 470L.  With a larger 67T front tail pulley and a longer belt, this upgrade increases your tail ratio from 3.7:1 to a much more reasonable 4.5:1, greatly increasing your tail power and authority without the need for long tail blades that reduce ground clearance.  It’s easy to install and will greatly improve your flying experience, especially at lower RPMs.

Photos in gallery show a prototype, and the design has changed a bit since.  The newest design has been in testing for over a year on several helicopters from the US to Canada to Australia.

This setup is best suited to 69-71mm tail blades, and running larger tail blades than that is not recommended.

Included in the kit:
1 x 3D Printed 67T Pulley (PETG Plastic)
1 x High Quality Taiwanese Fiberglass Reinforced Extended MXL Belt

Be sure to go through tail setup again to ensure proper endpoints for the tail servo after installing this upgrade.


The included M2 washers are optional.  They are only needed if you have issues with the pulley touching/rubbing on the main gear.  Whether or not you need them varies on a case by case basis.  We suspect there might be different versions of the ALIGN main gear hub resulting in slight changes in clearance.

Installation Instructions:

1. Remove the main gear/pulley and tail boom assemblies from your helicopter.  The standard ALIGN manual can be used for this process.
2. Install the 3D Printed pulley in place of the original.  The flat side of the pulley goes upwards when installed in the helicopter.
3. Fully loosen the belt tensioners.  To do this, screw the tensioning screws all the way in.
4. Replace the stock belt with the longer one included with this upgrade, then reinsert the boom The standard ALIGN manual can again be used for this process.
5. Once the helicopter is reassembled, pull hard on the tail boom while tightening the boom clamp screws.
6. If necessary, further increase belt tension by loosening the tensioner screws a little at a time.  Because of the extra load on the tail rotor and ALIGN’s unfortunate choice of using MXL belts on this helicopter, tension must be quite high to prevent slipping.
7. Go through the tail setup on your flybarless unit to ensure proper tail servo endpoints.
8. You may want or need to pin the boom using a 2mm self tapping screw through the tail box into the tail boom if the boom is slipping causing you to lose tension over time.


If you want a spare/replacement belt or pulley, please contact us directly.

Additional information

Weight 100 g

1 review for T-REX 470L Tail Ratio Upgrade Kit

  1. Jeff Dietrich

    This speed up kit works great! They pulley is made of a very similar plastic as stock, and the included tail belt is superior quality compared to stock. The installation was easy and the new tail has cured my low headspeed instability. I confirmed I am getting 4.5 turns of tail to 1 of main rotors. Great kit!

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