The demise of my Ceres f3f

[GuyB 3]

Hi

My Ceres glider lost connection with my Aurora 9 earlier today resulting in a total annihilation of the model from about 250 ft. 

The aerial from the reciever was poking out of the right side of the fuselage. I started to get intermittent signal as the model was flying away from me to the right. I was trying to lower it and come round to land as I lost signal completely 

I had packed the rest of the aerial (95% of it) badly underneath the receiver

This has not happened to me before . I have flown the model regularly for the last 4 years  

Any  thoughts on what I did wrong do this becomes an isolated incident?

No one was hurt and I am insured through the BMFA

Many  thanks

Guy 

 

[Sloper 146]

have you checked over any of the other parts, switch, battery wire loom servos any of them could be at fault and cause lost connection

[isoaritfirst 1,397]

More usually a problem with the power supply than the receiver. 

Battery fail or battery drained by some other component failure. 

Multile cell batteries can very easily go out of balance and appear to be fine on the charger but lack any ability to power a model for more than half hour. 

[Phil.Taylor 639]

Sorry to hear of your Ceres loss

Was it an early one with a carbon nose, or a later one with a 2.4 friendly glass nose? I've had both types.

The carbon one needs 2x antenna poking out of the nose - one each side

Phil.

 

[pete beadle 534]

Hi GuyB

How long had you been flying the Ceres that day? Had you flown it earlier? How long in total.....just the one flight?

How old is the Rx battery and did you charge it on a delta peak charger or one connected to the mains? How old is the charger?

As Mike says it could be simple battery failure.....how old was the battery?.....had you used the switch before? Were you able to find the model and retrieve the battery?

Sorry that it happened but, if you do actually work out what it was, you can draw a line under the incident and move on.....

Regards

Pete

BARCS1702

[GuyB 3]

Hi

Pretty sure the model had a carbon nose but my receiver only had one antenna 

I found the model in three bits and all servos worked and battery was charged.

I was not using an on/off switch , the receiver was plugged straight into the battery and the battery is fine and still charged 

From the above and the behaviour of the model just before and during the crash I am sure I lost connection  

In 20 years of slope and flat field soaring it’s my 2nd write off so not a bad run  

time to find a new model

Guy 

 

[pete beadle 534]

Hi Guy

Well done, you obviously have a very positive attitude

Unfortunately most electrical parts we use are made down to a price these days, and the connectors we mostly all use are not produced with high quality or longevity in mind either.......

Time to strip the covering off the Rx pack next,  I think and, perhaps to put your connectors on a Megger or similar and to waggle them to see if the needle dips a lot

What receiver are you using? and how old is it? Has it been used in other planes before, and what do the instructions for it suggest as regards installation?

Keep it up - are ANY of the bits salvageable? have a good look at them and see, won't you? You'd be surprised how many Ceres' are still owned and flown even now.....

Regards

Pete

BARCS1702

[isoaritfirst 1,397]

The result of low power or a battery failing are often shown as a loss of signal. 

Its hard to differentiate. If the receiver has flown for a number of years in this model. Is it likely to have suddenly failed?  Corrosion May cause a problem, but it’s much more likely that the problem lies elsewhere. 

That said, single aerial receivers are usually best kept for foam or similar models. But if it had been working for years.....

[isoaritfirst 1,397]

What battery pack? Four or five cell packs can often read as being fine, but under load fail if the cells are out of balance. 

Ypu can check each cell with a pin  and a multimeter. 

[GuyB 3]

1 hour ago, isoaritfirst said:

What battery pack? Four or five cell packs can often read as being fine, but under load fail if the cells are out of balance. 

Ypu can check each cell with a pin  and a multimeter. 

Hi

It was a Nimh battery pack that I charged overnight using a standard mains charger

thanks for the replies

Guy 

[pete beadle 534]

Hi Guy

Over the years I've had a lot of problems with standard fit mains trickle chargers.....first they usually don't have a meter, just an LED which doesn't show their cut-off point.....so you could be getting a lower input that you can't see

I'm still using an old SM Services Multi 8 and this checks start voltage and cut-off voltage and you/I can build up a record of how all your packs perform using it.....

It's especially good when you notice a charge rate or length has changed for no good reason

This incident may be caused by your trickle charger being unable to tell you it's no longer working correctly.....

Regards

Pete

BARCS 1702

[Martin Church 118]

Was it a 2/3rds af pack similar to this?

They are renowned for being troublesome.

I had a Crossover go in on one of these packs I’ve now changed over to liion 2s & fitted mks drop downs on all servos,

[Steve J 146]

@GuyB What is your test/maintenance routine for your NiMHs ? 

In my experience NiMHs benefit from being cycled on a regular basis using a decent charger (I do conventional NiHMs ever three months and Eneloops once or twice a year to check capacity).

I am also a big fan of fitting small voltmeters (c. £2 ea. from Banggood) to models without telemetry so that I can see what the voltage is like on power up.

Steve

[paul w 29]

Only three bits? That sounds eminently repairable to me!!

[GuyB 3]

5 hours ago, Martin Church said:

Was it a 2/3rds af pack similar to this?

They are renowned for being troublesome.

I had a Crossover go in on one of these packs I’ve now changed over to liion 2s & fitted mks drop downs on all servos,

Hi

battery was just like the one pictured

i am always carefull with my lipos, but I have never done anything with Nimh battery’s apart from charge, test the charge with a very basic battery tester and fly. 

Guy

[Steve J 146]

I would recommend cycling those every three months. Discharge at 2A, charge at 1.2A. Look at the values a few times during the discharge. Expect to put 1400mAh back in.

2/3A are good at delivering current for around 1000mAh and then they drop off.

Steve

[isoaritfirst 1,397]

those cells are notorious for failing after a couple of years , usually in the way I described, with one cell getting lazy and the others compensating . It gives a pack voltage that is high and appears fully charged, and probably still does after the crash, but when they are in that condition they usually won’t fly for very long before not having sufficient power to drive all the servos and give enough for the reviever  to work  . Test them afterwards under no stress and they may give a boltsgebyhst seems ok  

 

 

[Woodstock 350]

On 19/08/2018 at 08:33, isoaritfirst said:

 

.... single aerial receivers are usually best kept for foam or similar models......

That doesn't apply to Hitec.

[Phil.Taylor 639]

single 2.4 antenna with a carbon nose in the way of / blocking the signal doesn't sound like a good idea to me

(OP said single antenna on right, plane off to the right i.e. nose blocking the signal))

 

[Andy_B 1,121]

7 minutes ago, Phil.Taylor said:

single 2.4 antenna with a carbon nose in the way of / blocking the signal doesn't sound like a good idea to me

(OP said single antenna on right, plane off to the right i.e. nose blocking the signal))

 

but in 4 yrs of flying its never been in that attitude before ....in a landing pattern ........no matter where you put the aerial/aerials  there will be some blanking in some attitudes ...of course you could always go specky  and put a dozen receivers around the plane ...