T-REX 470L Tail Ratio Upgrade Kit

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  • Regular price $29.99


 

Back in stock!  Thanks to everyone who has been so patient waiting for these.  

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 an early prototype, and the design has changed slightly since.  The newest design has been in testing for over a year on several helicopters from the US to Canada to Australia.

Testing has shown this setup is best suited to use with the RotorTech 71mm Tail Blades.  Running other tail blades, such as the ALIGN 69mm, will not yield optimal results due to their inferior airfoil and tapering shape.  Do not use the ALIGN 74mm tail blades with this kit, the RPM is too high and you're likely to see vibration due to the 74mm plastic blades being very heavy, combined with the relatively small diameter tail shaft.  Tail performance with this kit and RT71 tail blades is excellent and you should not need anything larger, unless perhaps you're flying strictly at low RPM and want a bit more.

Included in the kit:
1 x 3D Printed 67T Pulley (ABS Plastic)
1 x High Quality Taiwanese Timing Belt 548MXL3.2 (Fiberglass Reinforced) 

Be sure to go through tail setup again to ensure proper endpoints for the tail servo after installing this upgrade as the length will change slightly.

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 two different versions of the ALIGN 470 main gear hub resulting in slight changes in clearance.  Install without the washers first, and if you don't have any rubbing, leave them off.

https://www.youtube.com/watch?v=lJMHs6s9mWw

https://www.youtube.com/watch?v=pdbxe3otGTM

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.