Done with build! (almost)

So close to done!

Since my last post, I installed the cyclic and tail servos, mounted the FBL, and installed the skids & blades. Here come the details!

Servo installation

The servo mounting locations on this heli are absolutely amazing. There is full and complete access to the mounting screws (in case of servo removal) and to the arms/horn screw without the need to remove any other equipment. (The same cannot be said of my Fusion 270; on that heli, you need to remove the FBL in order to access one of the servos. Ugh.)

Here is an example. The left aileron servo is right there, ready to be changed!

Trying to figure out where to run the wires from servos to FBL was. Not being sarcastic here. It was actually enjoyable. Once I decided on location of the FBL unit (which for me had to be the top of the tail boom mount since the Lynx servo wires are so short), most of the wiring figures itself out. There’s lots of little holes in the main frame that help out.

Here you can see I’ve run two of the servos’ wires separately from each other, which would allow me to change one of them out without disturbing the other.

I will say the one servo that gave me trouble was the front servo. Took me awhile to figure out how to avoid the main shaft collar and the left servo arm. I settled on using a zip tie to lower the exiting position of the wire.

Servo wire placement was challenging.

And if any of you are struggling to get your servo linkage balls (is that what they’re called) screwed into your servo arms, don’t be afraid to use a 0.9 mm hex wrench and widen that hole.

Used a 0.9 mm wrench to widen the servo ball hole.

FBL mounting

Once I mounted the servos, it became clear that I would need to mount the servo on the top of the heli rather than the bottom, even though the instructions suggest using the bottom for ease of access. (Not really sure how that would make it easier…)

Servo mounted on the top, not the bottom.

Briefly, I want to mention that I actually made a makeshift adapter so I could plug in my FBL and play around with the iKon2 software on the PC. Much more on that in the coming weeks!

Skids and blades make a happy heli

Mounting the skids and blades really make the heli come alive!

I went with the included 210 mm blades (rather than the 190 mm) to get a slightly larger-heli feel. Will it make a difference? No idea.

And for the drum roll…

Mechanical build done!

That red box with twisted colored wires sticking out the back is the Micro iKon2 USB adapter. The black mass next to it is a temporary makeshift adapter I created to connect the ESC to the FBL.

What else is there?

The build is basically done. I did level the swashplate and set zero pitch at mid-throttle, but I’ll save that info for a later post. Here’s what I’m still waiting to get to me to actually complete the heli:

  • Tattu 3S 1050 mAh XT60 batteries
  • Adapter for ESC to micro Ikon2
  • Castle Creations USB Link

And of course there’s the FBL and ESC setup that needs to be done.

It’s been 10 days or so since I placed my order for this Oxy 2. Very happy with my experience so far. However, if I had to re-do one thing, it would be better soldering jobs. I need practice. I may actually get a chance since the motor wires coming out the ESC are too long. Plus, I ordered a Hobbywing RPM sensor that I may install in the future. We’ll see.

What I’ve learned about soldering

I’ve learned that soldering is hard and that I’m bad at it.

I had to solder three separate female bullet connectors (2mm) for eventual connection to the brushless motor, as well as an XT60 male plug for the eventual eventual connection to a 3S battery.

The finished product don’t look that bad to me, but the shrink wrap does hide a lot. Luckily I think the actual electrical connection is sound. Time will tell.

As you can tell from the last photo above, I have the Talon 25 ESC mounted to the heli. Now I need to mount the FBL (Micro Ikon 2) then do the servos. Sadly I’ll have to wait before actually wiring and testing everything up. Apparently I need another adapter that didn’t come with the FBL. This picture shows the issue.

I need another adapter. Yay.

Most of the way through the mechanical build

I probably put ~12 hours into building so far. I work slowly, agonizing over every bit of the instructions. Here’s a run down of what I’ve done.

Tail assembly

The instruction start you off with the tail assembly. Right off the bat, they want you to somehow apply CA glue to the outside of the bearing without getting any inside the bearing. I hate doing that! Very paranoid that I’m going to destroy the bearing and have to wait a week until I get another one. Luckily it seemed to be okay.

My tiny work station (a glass TV table with an Align work towel over it) got real busy real fast.

The pieces were so tiny that I started using a standard-sized staple to apply thread locker! Unfortunately this caused me to not apply enough… I needed to go back and re-apply more.

During the assembly I was impressed by the quality of all the parts and how well they fit together. Certainly better than the Horizon Hobby/Blade products I’m used to. However, there were three parts (out of many) that seemed a bit substandard in either execution or design.

  • One end of the tail pitch slider seemed to be chewed up somehow, as if they crimping process or whatever they do isn’t gentle enough on the delicate metal and plastic.
  • The 3d-printed front tail boom insert (designed to prevent the boom from crushing) looked extremely unfinished. I needed to use a hobby knife to trim away the excess before it would fit. Others have stated this as well, so it’s not just me.
  • The tail belt tensioner bushing that’s near the tail fin isn’t centered relative to the belt. Now, this tensioner isn’t symmetric, and if I were to turn it around 180 degrees (left to right in the pic), it would become more centered, and some of the geometry of the supporting posts would make more sense. But the instructions very clearly state to put it this way, so whatever.

I should mention that I don’t expect any of the issues I mentioned to actually affect how the OXY 2 will fly.

The tail assembly overall took a long time. But I’m quite satisfied with the end result. Looks great!

Main frame assembly

Compared to the tail, the main frame assembly was a piece of cake. Not too much to report here, other than it’s convenient to know what electronics you’ll be using.

  • If you wait to add the motor later, you’ll have to do a tiny bit of disassembly to get the motor mount out. Not too much, but some.
  • The OXY 2 supports two sized of motors. Which one you choose will affect where the lower bearing block gets attached to the frame. Choose wrong, and you’ll have to do a fair bit of disassembly.

If you don’t know your choices, it’s not too big of a deal. Anyway, here are some photos of the main frame assembly.

Assessing and improving

I should mention that around this time I wasn’t happy with some friction I felt in the tail pitch slider as it slid along the tail shaft. After troubleshooting, the issue seemed to be some type of rough spot on the tail shaft. I disassembled, wiped it down (I had previously put a ton of grease on it to try to fix the problem), then reassembled it. For some reason that fixed the issue, so I’m happy now.

This was also the time that I noticed how little thread locker I was using. I went back and re-tightened all bolts.

Head assembly

The head assembly went smoothly. There are relatively few parts, so that helps.

I had two minor issues during this phase:
(1) I din’t realize initially that the thrust bearings that get seated into the main grips needed to be pushed down farther than I had initially. Took some muscle to do that! I would not want to try to get them out.
(2) I found it very scary and difficult to thread lock the two bolts onto the ends of the spindle (feathering) shaft. Too easy to accidentally get some on the thrust bearings. I believe mine is okay. Whew.

Next steps: Start installing electronics

The instructions require me to install the ESC next. This involves some soldering and deciding what battery connector I eventually want.

As I said above, I’ve probably put in 12 hours of work so far. Even though the helicopter mechanics are well over half done, the electronics installations are going to take quite a long time.

First bit of electronics arrive

The various components for my OXY 2 will be coming in multiple shipments over the course of about a week. The first bit to reach me was the tail servo, which arrived on Dec 24, 2018. Always impressed by the quick shipping from AMain Hobbies .

Tail servo was the first bit of equipment to arrive

UPS is scheduled to deliver the actual kit on Dec 26th along with a few other items! Really looking forward to that. Interestingly, that package was shipped from Vietnam and had a layover in Alaska.

Electronics choices

I went with the following choices for electronics.

  • FBL: MSH Micro Ikon 2 (same as Micro Brain 2)
  • ESC: Castle Creations Talon 25
  • Cyclic servos: Lynx DS-895-HV
  • Tail servo: Lynx H0988UHS-I Blue Arrow
  • Motor: EOX 1611 – 5500 kV

Nothing really surprising here. If you’ve ever shopped around for an OXY 2, you’ll recognize this as essentially the electronics combo package put together by Lynx, with the exception of my Talon 25 ESC replacing the usual HobbyWing 25 ESC. I’ve heard both ESCs are fine, but the Talon seems to be more popular, so I just went with it. Spektrum users like me seem to enjoy the telemetry capabilities. I especially liked that there seems to be a free coupon for the Castle Link USB adapter so that I can program it.

I’m also bought some XT-60 male plugs which I’ll solder into the Talon. I already have some charger accessories for the XT-60, so that seemed wise. Of course I do not have 3S XT-60 batteries. New heli, new batteries. Ugh. Even though I could solder on some female XT-60 plugs into my 3S 800 mAh 30C JST batteries, that capacity is just a little bit below what was recommended by Lynx for the OXY 2. I’ll save those batteries for my Blade 230 S V2.

My first non-Blade kit: Lynx OXY 2

As of this writing, I have owned 3 different Blade collective pitch helicopters: Nano CP S, 230 S V2, and Fusion 270. Recently I decided to take the plunge into assembling my first kit from pieces. A Lynx Oxy 2! This means I need to select servos, ESC, motor, and FBL/receiver. Eep! Although I’ve replace a few mechanical parts and some servos on my Blade helis, most of this process will be a learning experience.

Lynx? OXY?

Lynx OXY helis are relatively new. Lynx has for many years produced high after-market upgrade parts that are of the highest quality, and from what I hear their line of CP helis are no exception.

Image from LynxHeli.com

The OXY 2 line of helicopters—which I chose for my first build—is the smallest offered from Lynx. Currently only a “190 Sport” edition is offered, which is designed to use 190 mm blades. I went with this size for safety and affordability.

There’s much more coming! This blog will over-document every step of my choices, assembly, programming, and tuning. Stay tuned for more!