frank3246

I maidened my Multiplex MiniMag a few days ago in my back yard, but without much luck. Everything is "virgin" on this MiniMag setup, and arguably the pilot as well:

Equipment

- Warp 4 6-turn brushless inrunner
- APC 7x5E prop w/Hyperion prop saver (what is Hyperions's Web address, anyway??)
- CC TB18 ESC
- 3S LiPo 2150 20C (DN Power), fully balance-charged
- Optic 6 Tx
- Hitec HFD-08RO Rx
- 4 Hitec HS-55s

Configuration: Motor<->1.5" space<->battery<->ESC on the sidewall<->1" space<->Rx

I did not put a capacitor on the motor - am I supposed to?

The Flight

I fly only in my rural back yard where there are no power lines around, and I've flown my EZ* many times without electronic incident. Just some hungry trees.

About 40 degrees outside. The first few attempts at take-off ended up with the plane hitting the ground maybe 30 feet away, but not terribly harshly. When I got someone else to throw it, I was finally successful. She took to the air pretty smoothly and I soon turned her 180 degrees at about 30 feet altitude.

After only about 20 seconds in the air, the motor/prop began to "chatter" in mid-flight. The plane wasn't traveling fast, and I don't think the throttle/RPM was too high for the prop saver o-ring. I turned her again (heading toward a lake!) and landed, again not terribly hard. I picked her up and started the engine but it sounded fine, so I'm clueless about the source of the "chatter".

The next attempt to take off, the plane nosed into the grass pretty hard. I walked up to it but she wouldn't respond to any Tx commands (throttle/servo/elev/ailerons) from even three feet away. I unplugged & replugged the battery, turned off & on the Tx. When I plugged in the battery, the ESC would beep it's opening signature following by three beeps, but w/o the trailing signature it normally has. I tried this several times. When I turned on the Tx with the plane on at this point, the servos seemed to twitch just a teeny bit. I turned everything off for a few minutes and brought her inside, and she remained unresponsive on my bench.

What's Going On?!

I set her aside a few days. Today, using the same equipment w/o any charging, on the bench she responds fine!

I soldered the battery and ESC Ultra Deans and gold bullets to the ESC myself, everything else is factory. Because the ESC responded to the battery but not the Tx, I think the battery is OK - it registers about 12V.

Any ideas as to why the plane's electronics stopped responding in the field, but is OK now?

jzrf6c

I've only seen capacitors on BRUSHED motors to reduce the noise generated by the bruches. It could be the cap is causing a problem with the control signal to the brushess motor.

frank3246

Thanks for responding. jzrf6c. It seems the ESC won't complete it's initialization "tune" until the throttle is all the way down (and the Rx is able to sense it). I've addressed the chatter by adding an aluminum ring to my APC prop. But I'm at a loss to explain why the system wouldn't respond outdoors, I may have a component that's sensitive to the cold. Time will tell.

jdetray

Do not put a capacitor on the motor. Brushless motors don't need them and should not have them.

- Jeff

electriceye

As the setup is new and therefore the battery not cycled, plus you made attempts to fly, are you sure it is not just a matter of your battery starting to run down? That might be why it ran OK when you picked it up-You had the motor turned off for a while? Did you even start with a full charge?

j stumbler

The easiest thing to check first, is for interference. You said you have had good luck with your other plane, but just to make sure that is not the problem do a range test. Have someone stand with the radio where you normally stand, then walk around with the plane to see if you get hit anywhere. If that's fine, then test the individual electronic components, using a process of elimination to find the week link.

I hope that helps,
J


[link=http://www.commonsenserc.com]Common Sense RC[/link]

frank3246

Well, I used two different fully charged batteries in both the plane and Tx with identical results. Interference is unlikely as I am very rural (and other plane with different Tx/Rx is unaffected), and the Rx wouldn't respond even from three feet away after it acted up. However response was fine for the first few minutes into the flights.

There is no cap on the motor, I was just asking whether there should be. Turns out they sould only be installed on brushed.

I've sent the Tx back to Hitec per their suggestion. Hopefull they'll find the root cause.

Solid Hit

Have you checked the rx? It could have been a bad or loose crystal. Does the Optic 6 have the spectrum module? The module can be a problem but an easy fix without having to send it back to Hitech.

frank3246

Thanks for your ideas...

The Hitec Crystal was indeed plugged into the Hitec Rx tightly. I don't know what else I could check for on the Rx.

Yes, the Optic has the Spectrum module, which I had taped per Hitec's recommendation. I sent back both the Tx and Spectrum to HiTec for evaluation (and to put the "corrected" replacement back case on the Tx). I didn't send the Rx back because it's installed and I was too lazy to uninstall it.

One thing I could have done right after the failure was to change the Spectrum's frequency and test the Tx on my other plane. I may have to do that if Hitec finds nothing wrong (ugh).

Solid Hit

The crystal may be plugged in tightly (after loosing a crystal in flight, then the plane of course, one time I now put a piece of tape across it just to be sure) it can still be bad. If it has ever been in a crash or even if it hasn't, it's worth replacing to see if that makes a difference.