Serious Lepton glitches

[funkykeys]

Hey all,

My Lepton has become the Glitchmeister Meisterglitch. After 2 minutes of flying into the second battery pack (with a few minutes in between to cool the motor down), it’s locking out for around 2 seconds with full loss of radio control. Once control comes back I can safely land, but I've had a couple of close calls during testing. Luckily, no crashes… yet.

Assuming it’s bearing-related, I’ve replaced the main bearings, 1-way, the pair of bearings that sit on top and bottom of the 1-way and the pair of belt tensioner pulleys. So far, no cigar.

Here’s my setup:
- 4S setup with FlightPower 3700 packs
- stock Hyperion 815kv motor
- stock 22t pinion
- Jazz 55 ESC
- Medusa 6V 3.5A BEC
- JR 790 RX
- JR 9303 TX
- MAH mains
- MJP carbon tail blades
- carbon boom
- Airtronics 94761 servos with webbed nylon shroud around the wires
- MJB frame stiffeners and lift kit

I haven’t replaced the bearings in the tail drive box yet, but I was also considering upgrading to the Kora motor (not sure which model to get… any suggestions for 3000-3200 HS?)

BTW, all wires are tight in the receiver, the crystal is tight and no wires are touching carbon, since they’re all surrounded by shroud. I do have the 401 wire running along the frame just above the motor, but since this only happens after around 8 minutes of flight time (6 mins on first pack and first 2 mins on second pack are OK), I’m guessing it’s nothing but bearings… maybe the motor.

Any other ideas on what else could be causing this?

[prototype3a]

If it's easy to remove, I'd try it with out the the medusa BEC to see if that's the cause. I'd also try another receiver. If you're using a base loaded antenna I'd definately try another receiver that uses a full length antenna. I assume you are using a PCM (not FM/PPM) or similar setup if not I'd definately switch.

[rotodingo]

With 4S you need Kora 15-12 motor. with 23 (3000) or 24T pinion (3200).
I have this motor with also the Jazz 55. So you can trust this. You can also use 5S with 19 or 20T.

Nicoals

[funkykeys]

prototype,

Since the Jazz 55 requires a separate BEC, what one would you recommend? I hate to go re-soldering that whole gammut, since it's such a pain. What's odd if it is the BEC is that it does it after 8 minutes of flight. Both the Medusa and Jazz are just over room temperature.. maybe 90 degrees at most... so I doubt it's overheating. If it weren't functional, I'd probably see it within the first minute. I'm not writing it off; just doesn't seem like the issue, given the circumstances. Same goes for the receiver.

I'm using the Dean whip antenna with 6" of receiver wire (minimum length should be 4"). Wiring is tightly soldered and wrapped in heat shrink. Same goes for the antenna itself. All of my birds (Trex 450, which is sold; Stratus and Trex 600) use this exact setup, though the Stratus and 600 are using a JR 639 receiver. None of them ever glitch.

Yup... PCM.

[funkykeys]

rotodingo,

Thanks -- I think I'm going to buy the Kora 15-12!

[prototype3a]

Sorry, I forgot about the whole Jazz 55 BEC thing as I have the 80-6-18. Anywho... if it's happening towards the end of the flight I'd tend to believe it is the bec and it's not supplying the required voltage at the end of the flight when the main pack is running low. I'd want to bench test it monitoring the receiver voltage. If you do this make sure to work the cyclic throughout the test so the bec is being loaded by the servos like it is in flight.

[funkykeys]

prototype,

That's an excellent idea! Although my gut instincts are pointing to bearings -- most notably the motor, since it would seem like they're heating up, expanding and chirping, and since I've replaced every other bearing in that area, so the only bearings left would be the motor, if that's the case -- it's still very possible that the BEC is acting goofy. Medusa BECs are known to be a little noisy as well, so that could also be causing receiver interference.

[rotodingo]

Why do you use a separate Bec? The one included in the Jazz 55 is a switching type one. I'm full digital on my Lepton and no trouble at all. The Jazz bec is very good about noise. I tried a chipe u-bec and a real U-bec from cool flight systeme and both of them was reducing the radio range. First one is not usable. The cool flight systeme one is a little bit better but not much. I had the same radio range with the Jazz and a separate Rx batt. It's impressive! Remove the medusa and try just with the jazz. You will have only 5V, it's the only consequence, but it will give you clues. On mine it's working well (3*Futaba 150 and 1 Graupner DS3781, Gy-401 and 146iP receiver). I also have an Hyperion cool bec wu id didn't tested it. Your problem could be just radio noise problem.

Nicolas