TDR ( dotting the I’s and crossing the T’s)

There are a number of videos and blogs detailing building a TDR, so this article covers all the stuff past the normal build.  Clicking on all of these pictures will bring up larger images.



The TDR doesn’t have a lot of room for electronics, but it does have enough room for everything.


1. Satellite Wires: What you see in the above picture are two custom satellite cables from Custom Spektrum satellite cables.  They are 3” and 7” long 20ga. cables. The crimping tool for these wires is prohibitively expensive and at $4.99 each these custom cables are a great option.  At the top I flipped the elevator guide block around so that the flat side was facing backwards for my top satellite.

2. Shortening Servo wires: If you want to tidy up your servo wires then you need to take an active role is cutting, crimping and cleaning things up. Here is an RC servo connector kit that should help a long way with this. In this case the only wire that needs shortening is the one from the tail servo.

Below shows sheathing from the elevator servo.


Below on the left side of the frame you can see the sheathing that covers the left and right servo wires. The sheathing is pushed forward to the base of the servos and is cinched to the side of the frame to keep it clear of the main gear.


3. ESC wiring BEC cables: Jan recommends removing the toroidal cores, which I have done. The BEC cables can then be sheathed together. 


Tip: I recommend marking the Master BEC cable plug with a silver permanent Marker on both ends to tell them apart as they are plugged and unplugged from both sides. Also do this for the servo wires. I used to put black stripes on  the servo wires, but this looks better as it is hidden away from view once the wires are plugged in and it is more explicit.


4. ESC 12S wiring: To simplify wiring shorten the ESC wires and use some of the cut wire to connect two EC5’s together in series. This creates a clean connection point.

5. Batteries: Related to wiring and to having something that will last I’m using Thunder Power 65C 6S 4400mah long packs shrink wrapped together using 4” Clear Heat Shrink.  They fit perfectly in the TDR and keep all the wiring in front so no extension cables are required.


To date the reports back on  the Thunder Power 65C batteries has been very favorable and people who have puffed numerous other manufacturer and even Thunder Power 45C batteries are saying that these 65C batteries are the real deal and work very well.


Jan recommends using a good plastic grease on the gears of the TDR. What I’m using Moly Kote EM-30L.  A little bit goes a long way. I loaded mine up in a plastic Hobby Syringe.


Blade Holder

The TDR doesn’t come with a blade holder. There are two good options for this. RadiX has a universal blade holder. You will need to cut a notch for the tail rod as shown in the picture below.  If you want to order from Germany you can get the blade holder on this page that already has a notch on it.


Shaping Servo Arms

Jan recommends using the arms that come with the Futaba BLS 451 cyclic servos. What you can see below are the steps I took to finish mine.

  1. Rough cut with Dremel cutting disk.
  2. Rough sand with 240 grit sand paper
  3. Fine sand with 800 grit sand paper
  4. Polish with Meguires Clear Plastic Polish and a Dremel polishing head.


Dying Delrin Gears black

So why bother?  The white gears show the grease and look dirty very quickly.

Use Black Rit dye powder in an old pan with marbles at the bottom to make sure the gears don’t get too hot and to suspend them so the dye can get to the undersides of the parts.  Your local Hobby Lobby has both marbles and Rit Dye.


Get water to a simmer, add the parts and turn occasionally and watch for about 30 minutes.


Heat Sinks

The TDR has a closed canopy that can cause some cooling issues so a serious heat sink can be a good idea as can NACA ducts in the canopy to allow cooling without adding much drag.

Below is a Zalman ZMNB47J heat sink that fits the Jive 120HV perfectly. Unfortunately it was purple. beforeafterheatsink

Drano Crystals are mostly Sodium Hydroxide a very strong base. About 10-15 minutes in a batch of warm water and Drano Crystals and you can strip an anodizing away. Beware this is a strong chemical reaction. You will need to rinse the heat sink thoroughly when you are done and use vinegar to help neutralize the base and possibly baking soda to neutralize the vinegar.


To attach the heat sink to your ESC Artic Silver thermal epoxy is the way to go. It creates a solid attachment point and conducts heat very well. Mix the two part epoxy together in equal amounts and then spread a thin covering on the ESC’s conductive pad. Store the two part epoxy in the refrigerator so it will last longer. It is more expensive than the heat sink is and you can attach many heat sinks attached with them.


This is actually a bit of weight and it makes sense to secure the heat sink so the conductive pad doesn’t try to tear away.


I wanted easy access so I ran two  6-32x 2” bolts through the heat sink with a lock nut on the back and a pair of Protos 500 battery O-rings along with velcro on the bottom of the heat sink to hold things in place.  I did add sheathing around the motor wires (to prevent chaffing on the frame after this picture was taken.

Carry Bag

The TDR is just too nice a heli to not have a nice hand bag for it. I’ve ordered a Wingbag for my TDR. It still hasn’t arrived, but I expect it will be a perfect fit and look fantastic. Mine will have custom TDR printed in large letters on the side. These are custom fit for the TDR.


Soldering things just right

I found the best way to solder the motor cables and batteries cables with EC5’s was to use a 200 Watt heat gun with a large tip placed right in the grove of the EC5 connector with an alligator clip holding the wire solid against the base of the connector. When the solder melts at the wire everything is hot enough to create a good primary bond. Add solder until the EC5 is full but be careful the fine strands of the ESC and battery cables will wick the solder up and you could end up with a very solid 1/2” of exposed wire past the connector.


Below you can see the final shrink wrapped result. Notice the sheathing used on the motor cables from the ESC to prevent abrasion against the frame.  A little bit of the soft side of Velcro tape can also be added to the frame just below the wires.



Final Product 



This article is not complete. New information will be added.


7 Responses to “TDR ( dotting the I’s and crossing the T’s)”

  1. 1 Jay Compton March 11, 2012 at 7:34 pm

    I think you did an awesome job in the build and documenting it. What you have done here is over the top and is very similar to my thinking as far as detail goes. I love the details truly creative!!!

  2. 2 Alister Lee March 12, 2012 at 8:53 am

    A top-shelf build and an inspiration..

    You probably don’t want to disturb your wiring now, but did you consider an Emcotec Safety Switch? I’d like to use one so I can stick with Anderson Power Poles..

    • 3 mkovalcson March 13, 2012 at 3:10 am

      I’m not planning on adding any additional wiring. I will be shortening my tail servo wire soon and I’ll take some pictures of that when I get to it.

  3. 4 patrick March 18, 2012 at 10:59 pm

    Hi , well done !
    just a question concerning the dying: no weakness of the delrin after boiling?
    thank you

    • 5 mkovalcson March 18, 2012 at 11:16 pm


      Delrin has a peak operating temperature that is above the boiling point of water. It has a continuous operation temperature just a bit below it.
      I wouldn’t recommend flying it immediately after boiling it just in case there was some sort of temporary softness or water absorbtion, but it should return to normal very quickly.

      The bottom line is that many people have done this and had no problems.

  4. 6 Augur June 18, 2012 at 1:57 pm


    I plan to put my SK720 also on TDR. Do you use it w/o powerbus? Some problems with brownouts or something? I like to use it without, but I am not sure if the SK720 bus can handle it.

    • 7 mkovalcson June 18, 2012 at 2:42 pm

      It really depends on your servos. The Futaba BLS 451’s are relatively low current and according to the jlog I’m not reaching the 10A limit of the SK-720 internal bus. However with JR 8717’s the current would peak past that limit. I’ve not had any brown out conditions yet. I do use a PowerBus on my T550 with 8717’s. The Kontronik JLog device is very helpful in letting you know if you need a PowerBus.

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