Trex 250 maiden session, Friday 10/9/15

This would be my 1st session flying the 250!  I hovered it a few times in front of my garage, but didn't fly around due to the limited space. 

It flew well, but I could probably use more headspeed. With the stock gearing the Castle governor maxed out at about 4200 to 4300 rpm. I had the governor set to 3800, 4000, and 4200 rpm.  I think I'll try 4300 for the next session and increase the governor gain. 

My flying buddy had his Mikado 480 and 550 out this time!  They were cool, but he didn't fly them as aggressive as his small helis. 

The 480

The 550

I forgot to take pics of the 250 since I was busy getting my flights in before it got too dark. 

380 repair underway!

I decided to start repairing my 380 that I crashed a couple of weeks ago, while waiting for my 450 replacement servo to arrive. First up was to replace the bent blade grip arms and inspect the spindle shaft. Luckily the spindle shaft wasn't bent in the crash :). After installing the new blade grip arms, I reassembled the rotor head. Job done!

Next up I removed all the cyclic servos, as they all broke in the crash. It was a pain to get the servo case apart!  Then when I did, it popped open so I didn't have a chance to take a photo of the gear positions!  Luckily I found a photo online of a similar servo and was able to figure it out. I then took a photo of the new installed gear set as a future reference. It was a pain to line all the gears up on their shafts!  Especially the center shaft as it went though 2 gears.  I coated the gears with some white lithium grease and closed up the case. Job done!

It turns out that the output shaft which the servo horn attaches to snapped in half during the crash. Probably because this shaft has many steps and features on it. Once the servo was assembled I plugged it into the servo test port of my iCharger 4010 Duo.  It worked!  Whew!  Onto the other 2 servos. 

The repair of the other 2 servos went much smoother, as now I knew what to expect. 

Gear set of the 2nd broken servo.  You can see the split in the output shaft. 

The broken output shafts of each servo. 

Trex 450 not flight ready after all :(

Well that sucked. 

Fried chip on the servo control board. 

Had to take the frames apart to get the servo out. 

After setting the endpoints for the Castle esc, I decided to reset the flight banks in the Brain FC to the following: Bank 1- sport with self level, Bank 2- sport, Bank 3- 3D. 

I then got the idea to use a channel mix to activate Bank 1 and self level, by pushing the trainer/bind switch. I successfully programmed the mix and tied it to the flight mode switch on modes 1 and 2. When in modes 1 and 2, if the push switch was depressed, aux3 would drive the governor function using aux2 for bank switching, to change to Bank 1 with self level. 

I tested it in the radio by using the channel monitor and it was sending the correct signals to the correct channels. I tested it on the heli, with the motor off, and the banks were switching correctly when switching flight banks with the flight mode switch and when I pushed the trainer/bind switch. 

I then plugged in my motor to test the headspeed  changes, which also switched flight banks. While holding the skids to the bench I spun up the motor. The 1st try it worked ok. On the 2nd try I noticed that the flight bank seemed to be stuck in bank 3, so I rebooted the FC and tried again. This time it seemed to be working correctly. So then pushed the rescue switch (trainer/bind). The servos went to a weird position and buzzed!  That's not supposed to happen!  I shut down the motor and unplugged the battery. After waiting a minute or so, I rebooted the FC. More buzzing and clicking, so I unplugged the battery and waited again. The next time I rebooted a puff of white smoke came out of a servo! WTF!  

I unplugged all the servos and plugged them back in one at a time to find the faulty servo. I was able to find it by the even bigger puff of smoke that it let out!  Servo 1 had blown a chip!  WTF happened?!

I then remembered that this FC's self level is sensitive to vibrations and my holding the heli to the bench by the skids may have sent too much vibration to the FC, causing it to freak out and drive the servos erratically, burning out one of them. At least that's all I could come up with based on the events. 

Now I don't trust this self level. Will it burn out a servo again? Or was my holding the heli down to the table the cause?  All I know is next time I plan to test the self level with the motor off, then with all the blades off, and on the carpet!

I then had to get the burnt servo out of the frame, which required that the entire frame be taken apart by removing a bunch of screws, that didn't fit any of my powered driver bits. WTF!  I need another set of bits!

I then did some research into a replacement servo. It turns out that my cyclic servos were discontinued!  FML!  I then hoped that I didn't need to replace all 3 cyclic servos so that they matched. It turns out that the servo which replaced my Align DS415M is the Align DS416M. The DS416M is practically identical to the DS415M, except for a slightly higher torque rating. It operates at the same voltage and speed as the 415.  Woohoo! Something goes my way!

I ordered that servo and a couple of parts for my 550 rebuild, so that I get free shipping. Hopefully I get the 450 back to a flying condition in time for the weekend. 

Trex 450 flight ready!

I moved the MSH Brain FC from my crashed 550 (which will be getting a Vbar Neo with Rescue), to my 450. I originally planned I put it in my 250, but it didn't fit between the frames. So I moved the 3gx FC on the 450 to the 250, and the Brain from the 550 to the 450. 

It took me all day Sunday to figure out how to correctly calibrate the Brain and set it up for the 450!  The elevator channel didn't want to calibrate.  It took me all day, breaks, and several attempts to figure out what was going on. The elevator servo needed to be reversed to move in the correct direction, but the endpoints in the software didn't reverse with it. So I was moving the stick in the opposite direction I needed to set the endpoint!  What I needed to do was set the endpoints 1st, then reverse the channel, then fine tune the endpoints by moving the stick one way check the endpoints but adjust it by moving it the opposite direction. Geez. 

Once I got that part sorted out, the rest of the setup went quickly thanks to my Soko kit and Brain setup wizard. 

The 450 is flight ready for some tuning, once the rain stops. In the meantime I need to get the 380 fixed. 

More 380 parts!

My other order with my new blades and servo gears came in last night. I have a few more things to finish on the 250, then I can start work on the 380. One upgrade that I plan to add is a Castle 10A external BEC.  I've been using a BEC capacitor in the meantime. 

250 Done!

I finished the wiring on the 250, completing the build. I did the best I could with the servo leads, but there's really no room for anything!  Lol!

I tested the power system and everything worked like it was supposed to ( after calibrating the esc end points). Once I break in all the batteries, I'll be ready for the maiden flight.

Tiny T Plugs! 

Trex 250 almost done!

Last night I was able to complete the tail setup, mount the esc, and connect it to the motor. The last few steps to finish are adding the battery connectors, mounting the satellite receiver, and routing all the servo wires. After that I can fly it once I break in the new Pulse 860mah 35c 3s batteries I got for this little heli :)

New Pulse batteries 

Double checking the settings for the 3gx flight controller