Freewing L-39 issues…Help!

[Jimmy]

Greetings,
I recently acquired the freewing L-39 from motion RC. I’m having issues with what appears to be very brief, intermittent “brown-outs”. I’m using an admiral RX 600 receiver. While on the bench, and watching closely, I’ll notice the red led lights go out momentarily during which control surfaces will not respond. This only happens on rare occasions which makes even more frustrating!
Has anyone ever had a similar experience or any idea what the problem may be? I appreciate all and any input!

Thanks!

[Evan D]

I assume you are not doing anything, switching channels, retracting retracts or something causing extra current flow?

I would start with the receiver, swap it out. I'm not a fan of the Admiral receivers but many are using the normal, not stabilized, version without issue. There have been a lot of issues reported with the SP version. After that I would bypass the MCBe.

[Jimmy]

Thanks Evan!
I will give that a try. And yes, I observed the led lights going off without any input from the tx. Weird! What rx do you use/recommend?

[Evan D]

I'm hesitant to make any recommendation because we all have our own experiences. I mostly use Orange receivers but I don't do any Smart* and minimal telemetry. I found they consistently give me a better range check than any other brand and have never had an RF issue. I so have a number of Spektrum brand receivers and a number of Redcon receivers. I shy away from Lemon though their new ones look promising. I have used Lemon satellites with good results. But again I make no recommendation but I do note when people have issues with any brand receiver, yes, even Orange. As with batteries I recommend people try what the think will work and if it works buy more.

[kallend]

Several people in our club have had signal loss issues with Admiral stabilized receivers.

[HangarQueen]

I would try to determine possible sources by elimination. First connect only one servo, test, the connect the next et cetera. Again for elimination purposes, leave the mcb-e out of the equation first, then add it to test for any influence.
Also, try the test with an external BEC (make sure you disconnect the ESC first), to see if that makes any difference at all.

[jetpltrich]

Nothing more disturbing than to watch your plane fly off and nose dive into the dirt destroying itself and you have no control over it. My old Futaba took four favorite planes that way and when I lost the OV-10 I canned the Futaba program and went with the Spektrum system. So far I’m having good luck, great range checks, and no holds and F’s down in the 70’s. I have a few GPS antennas that I swap from plane to plane and should one go down I should be able to find it. To date I have yet to find my OV-10, it’s lost somewhere in the thick forests of East Texas. Cease flight operations until you’ve figured it out, that’s my recommendation.

Richard

[Chevpro]

I lost a 70mm hawk to an RX600 receiver on my first flight. I read months after that these receivers do not like higher voltages. I was able to replicate your same issues on the bench with my rx. Swap it out for the spektrum and you should have no more issues.

Todd

[Jimmy]

Thanks guys!
I really appreciate everyone’s help! I’ll start with a higher quality rx and go from there…

[xviper]

The problem on this topic is to know which product is "higher quality". Does that translate into brand or price or ................ ????? I've had so called "quality" Spektrum RXs and some of those have failed. They are so much better now but that hasn't always been the case. How does one know? Admirals are simply re-worked, re-branded Lemons. I've only ever had problems with the older DSM2 Lemons and ones that didn't have the capability of adding a remote receiver. I don't use those anymore, but have not had any suspect performance from any of the newer DSMX/P with satellites. And even Orange had rough beginnings but the ones they've put out since those olden days, are solid. I still have a plane with an Orange RX and I have no worries about it at all. Money doesn't always buy "quality". These days, I'm stuck on Spektrum and Lemons. One is pricey. The other not so much. I also invest heavily in rabbits feet, horseshoes, 4-leaf clovers and a huge bag of salt.

[HangarQueen]

At our field, I've witnessed a couple of incidents that happened to pilots that would never cover up pilot errors behind 'brownouts' or whatever you want to call it.
First incident was a multiple failsafe situation with a Freewing T33, luckily at a more than safe altitude. He had this happen a couple of times with only seconds apart (the time for the receiver to re-initialize?), no control at all. He landed the plane and checked everything, never found anything wrong. I might be wrong (it was a couple of years ago), but I think it was a stabilized Admiral receiver, because I advised him to add capacitors to the power supply lines. He later crashed the model, but I don't know the cause of the crash (I wasn't present when it happened). This is a pilot that flies EDF jets almost on a daily basis, weather permitting.
The other incident was in the same year, right before my eyes, with another very experienced pilot. As he took of, immediately the model showed uncommanded roll, right into the ground, total loss. This was definitely a stabilized Admiral receiver, never could establish the exact cause. He actually threw away the receiver, didn't even want to sell it to anyone, even though we couldn't find any demonstrable fault with it. He did have an older Spektrum tx, I don't know the type as I'm not familiar with the brand, but I remember other club members trying to convince him to buy a more recent radio.
Some members talk about possible interference at our field, but that would have to be confirmed by more incidents with other brands too, which never really happened. Some refer to a distant corner of our field, but I suspect that any incident at that distance from our positions would be more likely due to some form of loss of orientation.
I've seen or heard lots of claims of loss of control or brownouts in the last few years, but most of them were clearly pilot errors, causing stalls, accelerated stalls and real spins (not the vertical rolling dive that some call a spin). But those two incidents mentioned above were truly intriguing and strange.

[kallend]

Admirals are simply re-worked, re-branded Lemons.

The re-working involves different firmware. The equivalent Lemons don't seem to have had the same problems.