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]

Helicopters, Radio Control

Sometimes it seems you can’t catch up. More Madhawk300 frustration.

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So, the replacement blades are just about here for the MadHawk300 FP heli. Awesome. Except, yesterday the dang thing flipped out, suddenly went to full throttle while I was getting ready to swap out the batteries.

It did the ‘Chicken Dance’ on the park bench, snapping off parts the tail rotor. Radio throttle response did not help, it idled down and was just sitting there vibrating wildly (due to broken tail rotor). Carefully reaching under I unplugged the battery.

Swapped the new battery in, got the TX and RX talking to each other… but what now? No throttle!

So, I now have two shattered main blades (replacements arriving today), broken tail rotor ($4.00 which I’d have to mail-order) and now.. neither motor is spooling up!

On the workbench this morning I checked the motors and radio. Seems the RX is no longer sending voltage signals to the motors. Great… why did it do that? Well, a good 6 channel DSM2 receives is about $35 so I checked on the price to replace this thing.

WTH?? Really? $50?!?!

ExceedRC RX2423 replacement cost.

Oh come on now! Worth $15, maybe. Ugh.. more parts. At this point I’m chasing my tail on this thing. It was only $100 new, and 1/2 of the price for the receiver? Might as well just buy a new one and use this for parts! Honestly, I liked the way it few, it was fun, docile and a good trainer, even if the range was HORRIBLE, which I thought maybe I’d fixed by moving the receiver further from motor.. but.. it freaked out and crashed before I could range test.

I’ve read many people doing upgrades to make the thing really reliable. Sounds interesting for certain! But.. then, why toss more good money after bad? Shouldn’t I just chalk this up to some good training and park the thing?

I mean.. for the price of the MadHawk300 I could have bought a EXI-450 AND TX/RX for about the same price!

Then I could get replacement parts locally. Now.. the above also needs:
– motor
– rotor blades
– ESC (electronic speed control)
– Li-Po battery

But it’s also easily upgradable.. with stuff like this, a full CNC rotor head and tail, plus some spare blades:

Or, as my final plan for the EXI-450 I’m waiting for, a scale rotor head:

Sweet 4-blade flybarless scale rotor head.

Update: 9-June-2010 — EXI-450 is here!

And of course you can get really nice scale bodies very inexpensively for the 450’s, especially when compared to the proprietary bodies for other cheaper birds. Here is a short like from just one online retailer:

Factor in cheap proprietary electronics, motors that notoriously fail (tail motors) parts that are not available in any local store, batteries that are a strange size… and you have an exercise in frustration as soon as you run into a snag. And even if you are an expert flyer, you’ll run into a mechanical failure, or electronic failure and voila.. the questions about WTF have you done begin.

So, I’m really REALLY looking foward to the arrival of the EXI-450 kit this week. I’m really bummed that I have nothing to fly right now. 🙁 But at least with the 450 if I break something I *can* get a local replacement part!

Conclusion:
Would I buy a MadHawk300 or Walkera 180x bird again. NO!. I was warned about quality early on, and I chose to ignore that advice of one vocal expert, compared to the many voices singing it’s praises. Well, guess who was right?

Will I fix it at some point? Maybe. But certainly NOT with factory parts. I might turn it into a learning experiment to see what I *can* do with it. But… to what end? I don’t know. The $$$ is better spent on a 450 or 600 class bird instead of patching together what is not basically an expensive paper weight.

Upside, if there is one, is that the radio that came with it might be able to be used as a simulator controller with a $10 cable. 🙂 Maybe I’ll pick one up on the way to work and see what happens.

Helicopters, Radio Control

Documenting research on 450 vs. 500 vs. 600 heli costs

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I clearly need to get starting on the construction of my first collective pitch RC heli. The only question is, WHAT size to buy? I’ve done a lot of reading, talking to people who fly them a lot.. and I’m leaning very heavily to going with a 500 instead of the typical 450. Or, I might just bite the bullet and go with a big 600 electric.

While I research this, I thought it would be wise to document that things I learned, not only for myself, but for anyone else that might be interested.

Electric R/C Helicopter Notes
  450 class 500 class 600 class
Battery Cells / Voltage: 3 cell / 11.1v 6 cell 7 cell
Rate / Capacity:   25C ~2300mAh  
Battery Avg. Cost $30 $120 $180
Speed Control
(ESC)		   70-100 amp  

DECISION! – Buying the 450-EXI.

OK, decided. Finally decided. I certainly could have afforded any of the 500’s (or 600 clones) I’ve seen, but I’ve learned a cruel lesson of late, with the MadHawk300. Having local parts is critical to me having FUN!. Having to search and wait for parts stinks. Luckily the local shop has plenty of 450 parts. But they don’t carry 500 or 600 parts. That alone was the deciding factor.

So.. I ordered the following:

Order Number: 854679
———————
Quantity Item
1 GY48V headklock gyro
2 FRP main blade for electric 450 helicopter(335mm)
1 EXI Leveler 450/400 (Green)
1 30A Electronic Brushless ESC Speed Controller [Volcano Series]
1 Alpha 400 (3500kv) Brushless Motor
1 EXI 450 ARF Radio Remote Controlled Helicopter Kit (Plastic Version 2)
3 9g servo
1 9G EXI Digital Metal Gear Servo D213F
2 main blades (these are replacement blades for MadHawk 300)

So, the clock ticks down on the delivery, scheduled this week of my first ‘Grown-Up’ hobby heli. I debated the $30 more for a metal version (or $70 more for the CF), but I plan to crash this thing, and I suspect that most of the parts on this that I’d upgraded out of the box, I’ll be replacing due to crash damage. Why waste the money? Plus, in the long term I plane to buy a nice scale body for it, with a cool 4 or 5 blade scale head (they can be had for around $150), and if I *plan* to do that, then why burn $75 on a CNC aluminum setup that I plan to replace soon enough?

I hope I don’t chop off a limb learning to fly it! 🙂

Update: 9-June-2010 — EXI-450 is here!

Helicopters, Radio Control, YouTube

MadHawk300 hover practice, however I killed tail drive.

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OK, this is frustrating. 20 some odd flights and the thing’s rear motor is going out. There is a dead spot in it, so, somethings on a hard right yaw, the motor does not start back up and it spins into the ground, breaking… more stuff.

I did manage to get in some good practice on the day before though:
WATCH VIDEO: MadHawk 300 Hover Practice

So I’ve started to research updates to this rear drive issue, and the lack of power in the main motor (seems to be losing power, turning freer than it should.. seems like it cooked too, too much hover practice and not enough cooling airflow?).

At any rate, I found this info on the Walkera 180 (same heli, different brand name) that might get me a really sweet flying ‘learner’ heli for friends and family.

I got this info off the RCGroups forum [LINK]:

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

Here is another thread [LINK] with similar solution. It might be overkill for what I want to do.

Another idea on 'fixing' the MadHawk300 shortcomings.

Helicopters, Radio Control

Blade CX3 nearly meets it’s demise – out of action

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Yesterday evening, was a great evening to fly. Not much wind, very very light rain and nobody at the ‘fly zone’ to accidentally kill. When you are unleashing an 8 year old piloting a P-51 Mustang model, these are things you need to consider. To be honest, he’s better at flying it than I am.

While the P-51 was zooming around the park, sometimes slamming into the ground nose first at full throttle (foamy planes are really good trainers) I took up the two Helis for some practice.

First up was the MadHawk300. The CX3 and Foamy P-51 are both bound to the same transmitter, so I could not fly the CX3 while the transmitter was in use. I’d done some tuning on it, adjusting the motor. The last failed flight attempt was dashed when on run-up the main pinion began to slip at 1/2 throttle, keeping the heli from getting off the ground. I’ve since lock-tited those motor motor screws.

It few well. Adjustments I made to the swash gave me some really nice control. At higher speed and throttle, helicopter flight dynamics are not at all intutive to a guy that’s used to fixed-wing models. But it still went well, with a couple of hard landings, no big deal.

Then, it happened. While at the east end of the part, close to one of the Pavilion buildings, the tail suddenly started to swing wildly, it accelerated upward, then nosed rolled right and slamed into the pavement at near full throttle, doing quite a number of the landing gear and main rotor blades.

Madhawk 300 with broken landing skid.

🙁 Nothing that was too tough to repair, but I didn’t have the wrench to replace the rotors on site.
Toasted main rotor blade on the Madhawk 300.

At this point the battery on the P-51 was running low. I recouped the transmitter and started to fly the CX3. It was flying very nicely. Nicer than the Madhawk in fact! Zoomed round the park, turned on and off the model navigation lights, did some high speed passes, landings, just some fun landing.

Then, it happened.

Right in the same place the MadHawk had trouble, the CX3 started to go crazy, and started to go into the TBE death spin. I tried to regain control but no luck. It accellerated upward, then nosed over and went straight down, nose first into the ground at full throttle. 15′ was more than enough room for it to gain some momentum.

CRUNCH. It was not a nice scene. The following photos are after I attempted a field repair on the fusalage to fly again. Unfortunately it would not happen since the radio and transceiver were no longer talking to each other.

Once home, I tore down the heli (I’m getting far too good at this) and discovered that the radio receiver took the full-force of the crash. Part of it’s case was ripped off and one of the dipole antennas was missing. Oh oh!

Helicopter on the operating table. Trying to get TX and RX to talk to each other

Removed the plugs from the Spektrum AR6100e receiver in the heli, plugged in the 3-in-1 mixer, checked response. The mixer would not show it’s green ‘lock’ signal. It was not until later that I noticed that the signal lock LED on the AR6100e’s front was actually missing. But it was at that point I realized, that not only was the body smashed, the lower section of the frame mounts for the battery are broken, but the receiver is, completely, shot. I’ve broken at lot of things crashing R/C aircraft, but never destroyed a receiver. It’s at this point I’m thankful for using Spektrum R/C equipment. Replacements are 1/2 that of Futaba or JR radios. Still, it’s a $55 part. Ugh. 🙁

Close up of AR6100e broken receiver (unmounted) and 3-function mixer (mounted)

I don’t want to order a replacement receiver unless I *know* that’s what is broken. So I dug up the AR56200 full-range receiver I have, wired it in to the heli’s remains, and tested. Viola. 3-in-1 mixer lock and receiver lock. It’s a go. Now I just need to decided where, and when, to buy a new receiver. In the mean time, she’s out of commission.

At least I still have the MadHawk300 to fly. And if I crash that into pieces, well.. I’ll just say I have a contingency plan arriving for that soon as well. ):

What's next!?!

Helicopters, Radio Control

Digging this MD500E Scale Helicopte vid

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Found this on the XHeli.com Facebook page. Love the sound of these things.

I’m anxiously awaiting the arrival of my EXI-450 from XHeli.com, hopefully in the next week! Then I’ll have to build it. Then learn to fly it. Then learn how to repair it after I crash. Eventually I want to add a body kit like this, and replace the stock plastic parts (ordered plastic on purpose, about 1/2 cost and I plan to replace it as noted) with one of these:

HAC 4 blade Rotorhead for 450 class Heli

Radio Control, Technology

R/C micro Li-Po batter charger testing

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It’s come to my attention, that the little battery chargers that came with the various helicopters, might not be working up to par. Taking longer than I want to charge is one thing, but not charging properly is another entirely! A recent visit to the hobby shops indicated that it’s common for them to fail. But, they should be easy enough to test to see if they are applying a full charge by the simple use of a multi-meter.

Thus, I dug up my trusty Fluke (it must be over 25 years old now), put in a new 9v battery and started some testing.

All batteries here are Lithium-Polymer (Li-Po) 2-cell 7.4v batteries. 2 of the batteries tested are for the Blade CX3, the other for the Madhawk 300. Here is a link to the chart I created to document the batteries I’ve used.

  E-Flite Battery Charger ExceedRD Battery Charger
Exceed-RC 7.4v 1000mAh 8.4v     8.4v    
Tenergy 7.4v 900mAh 8.43v     8.43v 8.43v  
E-Flite 7.4v 800mAh 8.43v 8.38v   8.43v 8.43v  
Hyperian VGX3 #1 8.43v          
Hyperian VGX3 #2       8.43v 8.43v 8.44v

Results

Testing so far indicates that the chargers, although slow, are doing the job. One battery, the E-Flite 800mAh seemed a little down on power during the 2nd cycle of the test. It might already be suffering some degradation of performance. If that’s the case, it’s pretty pathetic. I plan to run each through at least 3 charge cycles to get a decent dataset.

Helicopters, Radio Control

CX3 repaired and flying again!

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The Blade CX3 is repaired and flying again! The $22 aluminum swash plate repair, actually has the thing flying better than it did right out of the box!

E-Flight OEM Plastic Swashplate E-Flight Upgrade Aluminum Swashplate

Here is a 3 min video of first test flights in the studio, and finally my 8 year old attempting to fly it, for the first time, outside! The crosswind was playing havoc but he did a pretty good job of keeping things together. I think he’s going to be a good pilot some day.

Even though it’s a Toy Co-Axial helicopter (a $200 “toy” to be exact), with the upgraded part, it’s a joy to fly. There is something so therapeutic about an activity that puts nice big genuine smile on your face. And in the end, what price is too high a price to pay for some joy? 🙂 Even though I’ve “outgrown” this helicopter in about 1 week of intense practice, I still want to keep it around, and even put some more upgrades on it! Such as this cool LED strobe kit I’ve seen on the web. Here is a video from a guy that I think, sells the best of them:

Here are a few pics flying it outside, just before dark. Shot with an f2.8 200mm lens, 50D camera set at ISO1600 and roughly 1/30th second shutter speed. Despite the slow speed and high ISO, I think the shots are work posting.

Blade CX3 spooled up and ready for takeoff.

Blade CX3 spooled up and moving out. Still in ground effect.
Blade CX3 after battery change, ready to go again.
Blade CX3 in flight.
Blade CX3 flies overhead.

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