Tag Archives: exi-450

Helicopters, Radio Control

EXI-450 Helicopter — Build Day 4

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The fourth day of construction starts with preliminary radio programming. Based on A LOT of information floating around on the web, I’m going to start off with the following settings for the bird. The manual for the radio itself is 139 pages, 80% or more of which are specific to the two primary programming modes, AEROCRAFT and HELICOPTER. I’ve said it before, I’ll say it again. The advances in R/C radios and equipment over the last 10 years is staggering.

NOTE: It turns out some of these preliminary settings were DEAD WRONG – Those in red were changed. See DAY 5 Setup for the corrected values!

DX6i EXI-450 Programming
Dual Rate & Expo
  Aileron Elevator Rudder
  100% INHibited 100% INHibited 100% INHibited
Travel Adjust
  Throttle Elevator Gyroscope Aileron Rudder Pitch
  ↓100% ↑100% ↑125% ↓100% ↑100% ←100% ←125% →100% ↓100% ↓125%
Sub Trims
  Throttle Elevator Gyroscope Aileron Rudder Pitch
  0 ↓32 ↓10 0 →40 →38 →23 0 0 ↓16
Gyro
  INHibited
Throttle Curve
  Low 1/4 1/2 3/4 Full
Normal 0 % 40% 25% 75% 50% 85% 95%
 
Setting up the Throttle Curve - Normal flight mode
Stunt 100% 0% 90% 20% 80% 40% 90% 40% 100% 40%
 
Setting up Throttle Curve - Stunt (3D) Mode
Pitch Curve
  Low 1/4 1/2 3/4 Full
Normal 50 % 50% 67% 82% 100%
 
Setting up Pitch Curve - Normal Flight Mode.
Stunt 15 % 27% 62% 80% 100%
 
Pitch Curve - Stund (3D) Flight Mode
Swash Mixing
Swash Aileron Elevator Pitch
  + 60% – 60% + 60% – 60% + 60%
Channel Mixing
  Master Slave Rate D U Sitch Trim
Mix 1 Throttle Throttle 0% 0% ON INHibited
Aileron Aileron 0% 0% ON INHibited
Elevator Elevator 0% 0% ON INHibited
Rudder Rudder 0% 0% ON INHibited
Gyro Gyro 0% 0% ON INHibited
Pitch Pitch 0% 0% ON INHibited
Mix 2 Throttle Throttle 0% 0% ON INHibited
Aileron Aileron 0% 0% ON INHibited
Elevator Elevator 0% 0% ON INHibited
Rudder Rudder 0% 0% ON INHibited
Gyro Gyro 0% 0% ON INHibited
Pitch Pitch 0% 0% ON INHibited
Revo Mix
UP DOWN
Normal

  0 % 0 %
Stunt

  0 % 0 %
DX6i EXI-450 Setup
  Throttle Elevator Gyroscope Aileron Rudder Pitch
  Normal Normal Reverse Normal Normal Reverse Normal Reverse Normal
Swash Type
  CCPM 120°
Throttle Cut
  POSITION – ACTIVE
Dual Rate Combination Assignment
  Dual Rate Switch: – INHibited
Power Setting
  B-US 247

Once the Transmitting programming was complete, continuation of wire routing was undertaken. A quick trip to the electronics store for a bulk pack of tie wraps and large diameter heat shrink tubing got things back underway.

With the larger diameter shring tubing, I was able to put add it to both the motor and ESC wiring harnesses where they run along or through the frame. Better safe, adding a few grams of weight, than watching a helicopter catch fire because of a short.

Shrink tubing added to motor wiring, broken or shorted motor wires could be BAD.

7 wires from the Gyro are protected with the shrink tubing, where they will run through the frame. This is before using the heat gun to shrink.

Pre-shunk tubing on Gyro wiring.

My plan to apply shrink tubing in all areas where wiring is on or near the frame is working out well. The combined Gyroscope and elevator servo wire groups are protected where they will run between sections of the rear frame.

Gyro tubing shrunk, wirting exits frame. Tubing also applied to main wire group (10 wires) where it will pass through frame setctions.

Preparing for first adjustments to blade tracking. Battery, canopy, ESC, motor all connected. Radio is not yet mounted because final tail servo setup has to be completed before finishing Gyro wiring and final radio installation.

Test fitting canopy with battery and ESC installed and wired.

Gyroscope and elevator servo wiring runs completed and secured. Radio will be mounted inside the frame just below re-entry point of the wiring harness. Shrink tubing covers wiring were it is near or in contact with frame.

Securing and running Gyro and elevator servo wiring

More wiring work completed. Final securing of motor wires and ESC control harness (center to right), and primary AR6200 Receiver box with control wiring installed. Final radio installation has to wait for final servo setup, travel tuning and Gyro preliminary configuration.

Lower rear, starboard side of frame. Primary radio receiver is on left side of photo.

30A Electronic Speed Control (ESC) secured to nose of frame. ESC is place are far forward as possible to help balance aircraft.

Electronic Speed Control (ESC) mounted in nose of frame.

Port side view of frame. Pretty clean looking compared to the starboard side.

At this point, the blade tracking can be adjusted. Here is a video of the three runs in the shop to check and adjust blade tracking. One blade required 2 full turn reduction on connector length, the other blad required a single turn of extension to get blades tracking equally.
VIDEO:

Helicopters, Radio Control

EXI-450 Helicopter — Build Day 3

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I only spent a couple of hours working on it tonight. I spent most of my time cooking for the kids. Tonight was no gourmet meal. However about 1/2 the time tonight was spent doing prep for tomorrow night. With 5 prime cuts of beef soaking up my proprietary beef rub overnight, it should be the basis of an enjoyable meal tomorrow.

So, with not much time I didn’t think I’d get much done. And, looking at the photos you’d probably ask how I spent 2 hours doing that. One word: soldering. One of the typically hidden, overlooked and far to often poorly done. Just for reference, here are some tips from Ask.com [LINK].

First, let me back track a little bit. As mentioned in yesterday’s post, I’d not been able to purchase a battery locally. Today, I took a chance and shot over to one of the really old-school hobby shops. It’s right next to the PLU campus in Parkland. As with all recent trips to the hobby shop, it wasn’t a cheap trip. I did, however, get a battery with a really nice mAh rating. The C level is fairly low (surge capacity) but for some training flights it might keep me out of trouble. And the price was pretty decent (about 1/2 of what other places were going to sell me much smaller battery for).

My first 3-cell Li-Po battery. It's a beast.

You can see in the photo here, the battery is a lot larger than the ‘big batteries’ for the MadHawk300. They look pretty wimpy in comparison (for reference, the MadHawk battery is the silver one marked ExceedRC on top).

Charging the new 3C 11.1V battery with a wimpy charger, 3 hours and counting.

It is only going to take about 3 1/2 hours to charge that battery with the wimpy little charger I have right now. That does not allow for much flying. :/

Back to the soldering story. The first step was to solder the Deans connectors onto the speed controller (aka ESC). Soldering the speed controller was a breeze. Good quality wire bound to the Deans connectors quickly. That was easy!

Battery, Deans connectors and speed controller.

What I spent probably an hour fighting with are the cheap micro-hair stranded aluminum wire on the battery I picked up today. It’s one of those things you just can’t see when you purchase them, since they typically already have some sort of connector affixed. Sadly, not the connector type I want to use. Here is a close up of a Deans connector I’ll be using.

Deans connector. Considered the most versatile and popular currently in use with RC Electric aircraft.

But I did get the soldering completed, after destroying one set of Deans connectors doing it. Quality of the joints are highly suspect, but they seem to be mechanically sound (tested). Voltage check on the battery before and after affixing the connectors did not indicate any measurable voltage drop due to resistance in a bad solder joint.
Here is a photo of the final production, on the ESC. I don’t plan to post a photo of the battery connector and soldering work. It’s an embarrassment. But after 3 attempts, one destroyed connector and starting to run out of wire for the battery, it’s going to have to be sufficient.
Male Deans connector in ESC.

With a 3-cell battery, connectors attached to battery and speed controller (ESC), I was able to finally power up the AR6200 long-range receiver and get it bound to the DX6i radio.

Setting up TX and RX to talk to each other.

One of the nice things about the DX6i, is it’s 10 model memory. Plus it has the ‘safe model’ feature. If you accidentatly forget to select the right model file for what you are flying, the RX and TX won’t talk to each other. RX binding data is retained with the model configuration. The concept here is to keep you from firing up your cool Delta Dart ducted fan jet, and taking off, only to find you’d left the transmitter configured for a conventional aircraft. That can create a REAL mess when you grab a stick full of elevator. The DX6i won’t like kind of mistake happen.

DX6i display for the EXI-450 model helicopter

With power on the system, plugging in the servos allowed preliminary servo horn positioning and fine tuning with the sub-trims. Just in case I lose my programming on the bird, I’m going to document the subtrims and other settings on this page:

Sub-Trims EXI-450 V2 & Spektrum DX6i
Throttle 0 Aileron +40
Elevator +32 Rudder +23
Gyro 0 Pitch 0

So, here is the current state at the end my tonight’s short work session. As you can see, there is a lot of work left to do. It still does not even look much like a helicopter yet.

EXI-450 slowly becoming a flying machine.

Helicopters, Radio Control

EXI-450 Helicopter — Build Day 2

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Spent a couple more hours working on the 450 last night. It’s coming along nicely. Today I didn’t need to grind anything.

A couple of the many tasks required to get this thing in the air, is balancing the main blades and applying Loctite to all metal to metal fasteners. To accomplish this I needed some very small metric hardware and a new tube of low-power Loctite. A lot of people are using Blue Loctite 242.

Loctite 222MS 'Purple' thread locker.

I don’t think it’s the proper compound for fasteners of the size we’re using, so purchased a large bottle (all they carried at the store) of the Purple Loctite 222.

The place I like to go for such things is Tacoma Screw (there is one local in my town, about 35 miles from Tacoma itself – for this I’m glad). It’s a jobber style shop with top-notch customer service, curious people behind the counter (by that I mean they like to talk about what you are working on) and always friendly. I picked up a pair of German Philips #0 and #00 screwdrivers:

A pair of good German screwdrivers.

Also picked up 100 2mm washers:

Pack of 2mm washers. Always good to have some washers on hand. This case $1.50

And finally, a long 2.5mm bolt and nylocks for making a home-brew pour-boy blade balancing rig:

Cheap balancing rig. Less than $1.00 in fasteners and an old vice.

I ran one of the nylock nuts down on the screw, about 2/3 of the way. Placed the blades on the bolt and ran down the other nut, just making them snug. I chose the nylock nuts because I knew that they would stay put once I achieved the snugness wanted. A few extra pennies spent to save a lot of potential frustration later. You learn these sorts of things being a gearhead for nearly 4 decades.

Close-up of the balancing operation. This worked very well!

The frame on the EXI-450 Plastic V2 is made of a stamped metal (you know, I think it’s aluminum, but I’ve not confirmed that), so some of the edges are rather sharp. To prevent the cutting/chaffing of wires where they exit the frame, I placed a small bit of high-strength tape (red) on the frame and then places a heavy duty heat shrink tubing over the wire bundle and applied heat to shrink with a heat gun, which works orders better than a lighter. You can get a cheap heat gun at Chinese places like Harbor Freight for around $10.

Heat shrink tubing applies to servo wires near body exit.

Here is the reciever I plan to use for this helicopter. It came with the Spektrum DX6i transmitter I purchased last month, and have been using with the ParkZone P-51 and Blade CX3. Not in this photo is the 2nd remote antenna/receiver that provides a very long range capability.

Spektrum AR6200 receiver I plan to use in this build.

Installing the linkage balls on servo horns was next. The idea here is to make sure the link bars are as perfectly vertical as possible when installed on the servo, so some trail and error is required to select the correct hole to mount the balls. In this case both of the forward servos were able to use the last hole. You’ll notice that the balls are mounted in ‘reverse’ so the ball is on the servo’s side of the arm. Once they are all installed and photos taken, the reason for this will be clear.

Setting up the servo horns and linkage balls.

Unfortunately, not all servo placements allow for such cut-and-dried installations. To get as close to pure vertical actuator alignment, you sometimes have to get a little fancy with the servo hardware. Once again, out comes the cheap Harbor Freight heat gun to apply some ‘persuasion’ to the nylon horn. After determining how much offset I needed, it was made very hot and then adjusted.

Having to get a little creative for the pitch swash servo horn.

I think this makes it a little clearer why the adjustment was made and how it all turned out. This is the pitch cyclic primary servo.

Modified horn test fitted in frame.

The fly bar on a Bell-Hiller head is critical to smooth and stable flight. To get the fly bar properly setup, the first thing that has to be done is make sure it’s absolutely centered. Measuring with a caliper seems like a pretty accurate method.

The flybar must be perfectly centered in the rotor head, so measure twice, move once is the mantra.

Larger photo of the Bell-Hiller rotor head, typical to R/C helicopters.

Bell-Hiller rotor head, with flybar (forground). Main blades not installed.

Unlike yesterday, I placed the ‘calling it quits for the day’ photo at the end of this post.

Progress report - End of Day 2. Looking a little more like a helicopter.

It’s looking a lot more like a helicopter now! I still need to get some important things before I can go much further, the most critical of which is my batteries! I think I mentioned it in the last post, being unable to source a suitable battery at the local hobby shop, soooooooooooo yet another package of stuff is on the way. I’m sure I could have save $30-40 on shipping if I’d spec’d out my needs better ahead of time. For someone that is such a stickler for planning, I didn’t do a very good job of it for this project so far! :p

MORE PARTS! Along with 3 450 class batteries, I'm getting a good charger!

Helicopters, Radio Control

EXI-450 Helicopter — Build Day 1

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I’m excited to be building this bird. I will say though, it’s a fair bit of work! Might be little much for a beginner getting into a hobby. I’ve been building models so long, I can’t exactly recall when I started! 4 decades of building is coming in handy here!

Perhaps it’s bad form, bad marketing, bad writing. Whatever.. I really don’t care, but here is the end photo from yesterdays work:

Result of a few hours of contruction. EXI-450

Yes, it took several hours to get to that point. It’s harder than it looks. Especially considering these kits do not come with ANY instructions. Thankfully, Will (owner of MikeysRC.com) has taken his time to document 15 10 minutes videos on how to construct one of these helis. I Just completed video #6.

Following are some snapshots I took during the construction in case you find the need to keep reading.

3500kv brushless motor mounted
Motor adjusment bolts. Locktite applied.
Tail drive belt, adjusted to proper tension.
Using grinder to open servo openings, required for some servos.
One of the cyclic servos installed in frame
2 of 3 cyclic servos installed. Hot glue used to hold nuts for install.
3rd of the 3 cyclic servos installed (rear)
3 cyclic servos installed, starting to check control arm alignment.
Helicopters, Radio Control

Future fixes for Madhawk300, but first, unpacking the EXI-450

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Yes, it has arrived! It’s here, and I unpacked it this afternoon. Not only that but I shot a little video of it (can’t resist) and I got over what you can get, online, for 25%-50% less than the typical ‘beginer’ helicopters sold in the local stores. Or, even online.

I’m talking about the Blade CX3 (about $200) and the MadHawk300 (about $130).

What you see in the video was under $150 delivered. But, only a small portion of that was the actual helicopter itself. Granted, you need to build it (which is what I spent some time doing today) and a few more parts (which racked up the rest of the cost). But.. the parts are vastly superior to those in the other example birds, and they can be obtained or replaced at most local hobby shops that carry even basic R/C aircraft.

So, here it is. About 5 minutes, shows you what you can get.

In retrospect, I’d wished I had just gone straight into the 450, as some people advised me to do, after I became comfortable with the Proto CX. Which, is still flying very well to this day. Small but tough.

Now, I have not totally given up on the Madhawk 300 concept. I think I’ll eventually fix it up and let the boy practice on it. He’s getting pretty good with the foamy P-51, and with the Proto CX. So.. once I get the Madhawk straightened out, I think I’ll use it for training / beginners and general mayhem when the 450 is being repaired, which, I suspect it will be when I fly my first collective-pitch R/C heli.

Mods another member of the R/C community used to resurrect a Walkera 180D (same basic heli as the MadHawk 300) into a really air-worthy bird:

CB180Q Conversion to Brushless
8g Outrunner – brushless C10 (2S)- 180 Serie
Tail Gear Holder from Q for Brushless direkt drive
26g Outrunner -brushless C20 around 4000 KV
pinion 16 T(metal) Modul 0,3, hole 2,3mm
20A ESC for Main-Motor
12 A ESC for Tail-Motor
Gyro WK-016 Gyro 8g 4-6V

RX 2801PRO
TX 2801PRO
good Lipo around 1200 to 1500 mAh

NOTE: He even provided a video to go along with it: [VIDEO LINK]