Sergio Salvi

Excellent pictures by: Michael R. and Andy H.

So-so flying by: myself

I’ve got the heli rebuilt and ready for the maiden flight!

Drove the usual 70km to the indoor gym on Sunday only to find out it was closed (err… I forgot it was Easter!). Then I see a nice park right besides the school, empty and with some nice soft grass, but it was very windy. Hmm… what the heck, I drove all the way here so I’ve got to fly it!

Training gear installed (thanks Andy for lending mine, I mean, his training gear) and off it went!

Blade tracking was bad with the stock CopterX woodies. I’ve replaced them with the $18 Carbon Fibre blades from Hobbyking and tracking improved immediately! I don’t think I’m going back to woodies, unless I’m just hovering.

Shiny $9 fibreglass UK canopy also provided by my beloved Asian hobby store

The tail slider was squeaking a lot and sometimes the tail would blow out when doing hard pumps on the collective (i.e., flying the heli upwards very quickly at full power).

I’ll have to add more grease to see if that solves it. It was squeaking more or less like this kitten:

In summary, flying outdoors was really nice! Good thing the gym was closed!

It’s been a month or so that I crashed my heli and since then haven’t had time to rebuild it.

On that day, I was practicing figure 8 circuits and was doing well for almost 4 hours. During my last flight, when no one else was flying (it was closing time), I decided to use the whole gym for my figure 8 circuits… well, overconfidence kicked in and I lost orientation — oops

So now it’s time to rebuild! I’m building my three additional CopterX kits at the same time, but only two will be ready-to-fly with all electronics installed. Heli #3 and #4 (the crashed one) will be used for spares

Cheap $14 camera from eBay (Hobbyking has it too now), attached with velcro and zip tie on the horizontal stabilizer of my CopterX 450:

Watch out: there are 4 versions of this camera for sale on eBay, but only the one with a microSDHC slot is the good version. There is a video comparison here: http://www.youtube.com/watch?v=LT8rqod3Gj0.

This is the eBay seller I’ve got my camera (#3 version) from: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160386693376.

Hobbyking is also selling this camera now, hopefully it’s the #3 version too.

Lots of info about these cameras: http://www.chucklohr.com/808/.

So whoever is looking to buy one of these cameras, make sure to buy the one with a microSDHC slot but not the one with 1280×960 video resolution.

Flying in a gym at Aerochoppers in Bowmanville, ON. Much better than flying in my living room

IMPORTANT SAFETY NOTICE: This heli is not supposed to be flown in such a confined space. It can hurt you badly if it hits you. I’ve taken a few safety steps since the first flight given the risks I was taking: always wearing safety glasses, never hovering with the tail pointed at me in case the tail blades come off and also not flying at eye level for the same reason. The throttle hold switch is always ready to be flicked (very important) — if you listen carefully, you’ll notice the RPMs going down before it crashed. My living room is “L” shaped so I was standing at the “foot” of it, kinda sideways to the heli. Safety first, but I really wanted to fly that thing Now I fly in a school gym.

This is one of the few steps remaining before my first test flight. I’ve used a swashplate leveling tool instead of trying to eyeball it or using a bubble level. I bought it from ReadyHeli and it is was pretty simple to use (Hobbyking has it now for only 3 bucks). Everything now is level, from the servo arms all the way up to the blade holders.

I didn’t have to readjust any linkage lengths; it was just a matter of adjusting the servo subtrims and travel adjustments (AKA ATV or End Points) on my transmitter. I think that’s because I had my linkage lengths already measured according to my previous post.

Video guides for this step: swashplate leveling tool instructions and MikeysRC CCPM/swashplate videos (part 1, part 2 and part 3)

My tips:

• When using the leveling tool, I found it easier to use a flashlight to check whether the tool is touching all three points in the swashplate. Have the flashlight some 15cm from the swashplate and hold a piece of paper on the other side of the arm. Then check the shadow on the paper: if there is any gap between the swashplate arm and the tool, you’ll see a thin horizontal bright line in the shadow projected on the paper. A few subtrim clicks up or down will eliminate that gap. Maybe this is overkill, but at least I can tell that my swashplate is perfectly level

• As suggested in forums, setup the rotor head symmetrically: at midstick, with 50 on the pitch curve, everything should be centered/level/at 90 degrees angles. That includes cyclic servos, seesaw holder, flybar cage, blade holders, etc. The videos from MikeysRC were very helpful for this step.

Great tip from gravityKills on RCGroups on getting exact zero-degree pitch:

Simply fold the blades back over the boom, hold the flybar and look at the heli from the side. If the two blades overlap exactly, it’s 0 degrees. I don’t know how accurate you can get “by-ear”, but this method is much more reliable than a pitch gauge. I also set the maximum positive and negative pitch this way, fine tuning in the field by comparing upright / inverted climb out.

The MD500E fuselage from HobbyKing has arrived! I had to try it on my other CopterX kit:

Hughes MD500E fuselage vs. standard canopy

Dialogue with my wife when showing it to her:

me: Look at this new fuselage I’ve got for my heli!!

wife: Ohhh, it looks nice! Did you get only one?

me: (speechless)

This scale fuselage looks really good and makes the CopterX 450 look bigger compared to the standard canopy. It will also help with visibility given its size and colour pattern. The build quality seems very good except for some tiny details in the painting that are not 100% perfect. It’s only noticeable if you look closely, so I don’t care — especially when it’s only $47 at HobbyKing instead of $300 from a local hobby shop.

Taller and wider. Approx. 300g of extra weight.

Unfortunately I’m not installing this body on my CopterX anytime soon because I still have to actually learn to fly my heli, so for now it will stay at home as a “prize” for myself when I actually learn to fly it properly. Check this page back in a few months for a status update

The manufacturer, KDS model, also has a greenish/military version of this fuselage but I think it is very hard to see when flying because of the dark colour and lack of contrasting colours:

Hughes MD500E military scale fuselage

There are many options on how to mount the electronics on this heli. I liked the idea of installing motor-related stuff in the front, near the motor (ESC and battery) and radio-related stuff in the back (receiver, remote receiver and gyro):

AR6200 receiver (plus remote receiver), G401B gyro and Turnigy 40A ESC

Left side: wiring of all 3 cyclic servos

Video guides for this step: T-Rex electronics placement and overview by Finless Bob

My tips:

• Servo wires: the wires of all my cyclic servos go through only one side of the frame. I didn’t like the idea of having a servo wire too close to the main shaft, like I’ve seen in other builds.

• Receiver and ESC: I’ve used adhesive backed Velcro to mount the receiver (Spektrum AR6200) and the ESC (Turnigy 40A Sentry). The AR6200 was positioned in a way so that the antenna wires are sticking out from the frame. Before applying any velcro or sticky foam, I cleaned the surfaces with rubbing alcohol.

• AR6200 remote receiver: it was mounted with the standard sticky foam included in the CopterX 450 kit. I had to cut two small squares in the left top and bottom corners of the foam to make room for the two tail boom block screws. I also made sure to mount the remote receiver slightly lower than the tail boom block to protect it during a crash. In a crash, the flybar paddles might (or probably will?) hit that part and destroy your expensive receiver.

• G401B Gyro: the gyro was mounted on the bottom of the boom block to protect it from a tail boom strike. This is very important, especially if you’re using a $100+ gyro (not me ). Some people say it is best to mount the G401B with a metal plate in between (boom block + foam + metal plate + foam + gyro) to avoid tail drift. The only metal place I had lying around was a PC slot cover, but it worked well after some cutting (25mm long). I used Futaba gyro foam pads (FUTQ1000) instead of the original ones from CopterX.

 

Foam and metal plate

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G401B Gyro mounted with foam + metal plate + foam

• Tail control rod: the CopterX one is too long, making the servo arm hit the gyro. I had to cut the rod by 3.8mm to be able to move the servo away from the gyro. Instead of cutting 3.8mm from only one side, I cut 1.9mm from both sides so there is still thread left. Now the servo arm can move freely in either direction without binding.

Top: original tail rod - Bottom: after 1.9mm cut

I’m back! Got the tail boom installed many weeks ago but didn’t have time to post it:

Video guides for this step: Craig Gagner – Tail boom installation

My tips:

• Check and if required re-screw the tail rotor control arm (it’s the plastic “L”-shaped arm). Mine wasn’t fully screwed on.
• Trim the two tail control ball links (plastic arms) with fine sand paper to make sure they move freely. Mine were clearly moving with too much friction. These are the surfaces I had to sand: