Hi everyone !
I recently converted my clouds fly to a night flying model . Its running on the same set up as earlier .
Radio - Corona synthesised 9ch 72mhz receiver
The night flying accesories are -
2.5m of LED's
2m of glow wire (powered by a high , audible frequency emitting module)
360mAh Tahmazo 20c 2s Li-Po

The clouds fly , prior to instalation of night gear only had a single flight . It flew perfectly fine.
The plane was flown by captain , it was showing perfectly normal behavior on ground . The first flight went perfect except for the motor suddenly stopping for a second and again continuing . This was observed a few times but only over the paddy field to the left .
The second flight , the plane had a lockout just above the paddy field (left of the feild) , the ailerons went to full deflection , the motor made a wierd sound and none of the controls responded . After reconnecting the battery , everything was normal . The crash caused slight damage to the nose , which took a single drop of CA and was back to normal.

After a range check we again flew the next night and it flew perfectly normal , the second flight during that night , the receiver again had a lockout , the damage was not very much , repaired in 10 minutes . We couldn't figure why this happened . An interesting observation was that the lockout took place around the same area where it happened earlier and also where the motor would suddenly stop and start again . Again when we reconnected the battery , things were normal .

Any idea what may have caused the lockout ? Why was this happening ?

Thanks ,
Sahevaan

There are lots of reasons for lockouts, a common one is low power.  Just because the controls responded when reconnected is not reason enough to rule this out. 

BTW, I hope you meant a lipo larger than just "360mAH" !  2s 20C may be border-line power, so the first thing to try is to fly with a better lipo.

The battery for the main power is a 2200mAh 11.1v battery , for the night lights , that battery is more than sufficient (the only consume around 70-80 mAh for 30mins , which is the Clouds Fly's flying time .

Dont have any idea what a 'audible frequency emitting module' is but in normal circumstances the esc is to blame. make sure none of the servos are binding, try with only one aileron servo. four 9g servos can be overwhelming for some esc's (with bec). If esc is good then check rx then tx.

Your Description gave me a feeling that there exists a Bermuda Triangel on the left of Paddy field.....

Now that makes much more sense  Although that 70-80mAH for 30 minutes sounds wrong.

Since you are on 72Mhz, try rerouting your wiring to keep the antenna away from the high power components... that seems to help in many such cases.

switch to 2.4 G Hz

With low power a 2.4g can also lockout, infact lockouts/brownout are more common in 2.4g.

Ehh... I don't know if airplane guys do this but car guys use " Glitch buster capacitors" when they have brownouts due to the servo drawing more current than the BEC can spare. It wouldn't hurt to try one in case that is the issue.

Companies sell these at inflated prices. If you haven't heard of them, they are capacitors connected to a spare channel on the Rx. DIYers( not sure if it's a proper term ) take a 10v 4700 microfarad capacitor and solder a servo cable onto it. It works pretty well when the BEC can't supply enough power to the Rx. This is an inexpensive investment. There is one car ESC made by Castle Creations called the Mamba Max Pro whose BEC fails when used with high power servos. People make do with the " Glitch busters" and some people use an external BEC with a " Glitch buster". Maybe that'll solve your problem...

Here is a tutorial if you're interested in trying it out...

The Cold Lights/ Rope lights are powered by a module produced by Align , it emits a high frequency , audible sound (sorry for being unclear earlier)
The ESC is the stock ESC supplied by HK for the CF . So far no other CF in hyderabad has had ESC trouble (many of us have CF's here) But i suppose it could be poor quality , or maybe the receiver ?
How can we use the Clouds fly with a single servo without a major modification ? Others are working fine on stock .

And Yes , sure i would like to try your suggestion iamahuman !

Just disconnect one aileron servo from the rx. This is just for testing, an experience flyer should not have much problem flying with one aileron. if the problem goes away then esc is the suspect if the problem stays then you'll have to play with rx antenna or try a different rx.   

^^ Good suggestion there.

What car guys do to check if their BEC is being overloaded is to overload it in controlled conditions. Try to run all servos at once and see what happens....

And specific to the AXN, I hope you have ensured that the hinges are not stiff.  This is one reason why servos would have to work a lot harder, and draw more current.

the problem here is the receiver...! i had faced this problem... the frequency locks in and gives you ground range but does not give you enough range when working with the motor running with servo in put and in your case even the lights....

this is a common problem faced( either common with me) on the corona 72. if you have such doubt throw away the receiver and get a new one.. i threw two...! 

In that case it would certainly be worth trying to isolate the receiver from the rest of the high power components FIRST !

Judging by the symptoms, it could well be that the Rx is extremely sensitive to the supply voltage. And also very prone to interference - note comment on location specific issues.

Also, is the Rx FM or PCM? I confess to not knowing much about Corona Rx except for one unit that I got from HK which turned out almost useless.

What was the Tx in use?

The Rx was FM and I was using my Futaba 6EXP .
There is no other place to put receiver , so we decided to experiment the same set up with a 2.4 system (around 5 others have the same set up in hyderabad , frsky rx )

FM Rxs are certainly more prone to interference as compared to PCM. I am sorry I was not clear when I spoke of "location". What I meant was the problem seemed to be evident in a certain flying area or "location".

My feeling is that you have a combination of things all working negatively: FM Rx, severe interference, a below par performing Rx.

Today we tried the CF with a 2.4ghz FrSky rx and JR 9X tx , it worked perfectly .
We were around 20 mins in the flight when the motor started pitching up and down , I thought the battery was low . We were just about to land the plane , it had a lockout just a few meters from the runway , and hit the runway nose down . The damage was quite critical , broken tail and deformed nose .
The problem was with the ESC i think . The same thing happened again , the lockout had all servos lock in full deflection and the motor making a whining sound .
What do you guys say ?

Seems like your servos are drawing more power than your BEC can supply and that is leading to what I think is a brown out.

Try the glitch buster and check it out. If it doesn't work out, I suggest you get an external BEC....

How about changing the ESC ?

I am confused... you have flown for 20 minutes, and it was fine for 20 minutes.  Why is this not just a case of the battery going low ?

We flew it for about 17 minutes . When we charged the battery it took 1455 mAh , the capacity of the battery is 2200mAh !

Check the individual cell voltage. 

Okay will do soon and post again