Maintenance Manual Table of Contents > Tail Rotor Modifications > GWS Direct Drive Tail
Parts Needed
All parts are GWS brand.
The parts needed to implement this upgrade are:
Part Name: Tail Blade with Adapter
Mfg Part Number: GW/H001-FD5002-030B
Vendor part number: FD030B
Purchased from: helihobby
Purchase link: link
Cost: $6.00 USD
Part Name: Tail Gearbox Housing with Vertical fin
Mfg Part Number: GW/HAS-002
Vendor part number: GW-HAS-002
Purchased from: helihobby
Purchase link: link
Cost: $4.99 USD
Part Name: Tail Motor
Mfg Part Number: GW/EDP-50H
Vendor part number: GWSEDP50H
Purchased from: Horizon Hobby
Purchase link: link
Cost: $10.49 USD
Part Name: Heat Sink
Mfg Part Number: GW/EHS-12
Vendor part number: GWSEHS12
Purchased from: Horizon Hobby
Purchase link: link
Cost: $1.50 USD
Figure 1 shows the parts.
Exploded View
Figure 1
Heat Sink Installation
Strangely enough this was the most difficult part of the operation. I used the GWS EHS-12 heat sink with the GWS EDP-50/H motor. I ended up filing a small chamfer on the inner edge of the heat sink to get the motor started. I applied heat sink paste to the inside of the heat sink prior to installing. This heat sink was very difficult to get started on the motor. It is an extremely tight fit, which is great for a heat sink, but it was very difficult to get started. Brute force was the answer. I bent the capacitor out of the way (Figure 2) so I could get a good push on the back of the motor (Figure 3). Once I got the motor started inside the heat sink I supported the assembly on blocks as shown in Figure 4 and pushed the heat sink the rest of the way onto the motor.
Okay - that was difficult! The rest should be easy… Now I can't (easily) rotate the heat sink into the proper position - it's too tight on the motor can. After scratching my head for several minutes I finally got out the channel-locks and a protective strip of rubber. I CAREFULLY wrapped the motor in the rubber and gently grasped the motor can with the pliers. Figure 5. Notice that I grasp the motor at the shaft end so as not to deform the can. I only squeeze the pliers enough to prevent the motor from turning. Twist the heat sink into the position you desire. Figure 6 shows the orientation I used.
I recommend doing a water break-in on the new motor at this time.
Exploded View
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Remove the old Tail Rotor Gearbox Housing
I tried using a debonder to dissolve the CA adhesive attaching the Tail Rotor Gearbox Housing (061) to the Tail Boom (056). I applied very small amounts with a toothpick as shown in Figure 7. I did this several times but the Gearbox remained tight on the Boom. I finally ended up using my dremel tool with a fine cut-off disc to carefully cut through both sides of the Tail Rotor Gearbox Housing (061) as shown in Figure 8. The Housing (061) can now be easily removed. Clean up the end of the Tail Boom (056) with fine sandpaper.
If you are in the process of performing this upgrade you may want to consider cutting off the Tail Boom (056) where it meets the Tail Rotor Gearbox Housing (061). The added weight of the bigger Tail Motor is difficult to offset by shifting the battery forward. A shorter Tail Boom prevents this. Regardless of which method you employ make sure you don't damage the Tail Rotor electrical wires running through the Boom.
Exploded View
Figure 7
Figure 8
Install the Blade Adapter and Blade
Partially thread a setscrew into both sides of the Blade Adapter. Slip the Blade Adapter onto the Tail Motor output shaft. Using the provided hex wrench tighten the two setscrews evenly onto the shaft as shown in Figure 9.
Press the rubber bushing into the Tail Rotor Blade as shown in Figure 10. It is possible to install the bushing on the wrong side of the Tail Blade so use Figure 10 as a guide to putting it on correctly.
Insert the Tail Motor into the new Gearbox Housing as shown in Figure 11. Align the screw holes while ensuring that the heat sink does not contact any part of the Gearbox Housing. Figure 12. Install the retaining screws as shown in Figure 13.
Place a washer on the Blade Adapter and then thread the Tail Blade onto the Blade Adapter as shown in Figure 14. The hex wrench is used to prevent the motor from turning while threading the Blade Assembly onto the Adapter.
When the Blade Assembly is completely threaded onto the Adapter install a washer onto the Adapter and then the retaining nut. Tighten the blade retaining nut snugly but do not crush the rubber bushing. Figure 15. Use Loctite on the Adapter thread if possible.
Exploded View
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Install the new Gearbox
Slide the new Tail Rotor Gearbox Housing onto the Tail Boom and route the wires to the motor. Carefully position the Gearbox Housing so that the tail motor is installed perpendicular to the Main Shaft (050). Figure 16. Don't use the Tail fin as a reference - it is too flimsy and could be bent.
You have installed the blade correctly if it looks like Figure 17. Notice that when the tail blades are rotated until they are vertical, the top blade's leading edge points forward.
Solder the leads onto the proper connection to give the correct rotation. Of course this can be changed by simply flipping over the tail motor connection at the 4-in-1 Controller.
The last step is to use a thin cyanoacrylate (CA) adhesive to attach the Gearbox Housing to the Tail Boom. I install the Housing and then apply just a drop of CA to the joint as shown in Figure 18.
Exploded View
Figure 16
Figure 17
Figure 18
A few last things...
Allow the CA to dry as indicated by the product's label. After a short run-up recheck all screws and the retaining nut for security. It would be wise to check these also after the next couple of flights.
You will undoubtedly have to adjust the 4-in-1 Gain and Proportion settings.
Check the aircraft's center-of-gravity (CG) as outlined in the owner's manual. You will need to move your battery all the way forward. If moving your battery all the way forward still doesn't provide the desired CG then consider cutting an inch off of the Tail Boom. I did not have to cut anything off of the Tail Boom.
And finally... was it worth the $22.98 (plus shipping). I think the answer is "Yes" in varying degrees depending on what type of flying you do and how well you do it. If you're an experienced pilot you will love the tail authority available. A brand new guy who is still putting the tail in the dirt fairly frequently will probably be frustrated by this mod. Wait a month or two. For the people that are primarily hovering, you will notice a slight improvement in tail response.