Lipo Fire

"Do you need a reminder about what can happen around lipos, this is the 3rd lipo fire we have had within our club of around 70 members within 3years.
Whilst there is no conclusive evidence to point to why this lipo fire happened. It was only good fortune that our member didn't burn his house down.
If your running a first generation Lipo charger without a balance lead facility maybe the time has come to think again."
Do you need a reminder about what can happen around lipos, this is the 3rd lipo fire we have had within our club of around 70 members within 3years.
Whilst there is no conclusive evidence to point to why this lipo fire happened. It was only good fortune that our member didn’t burn his house down.
If your running a first generation Lipo charger without a balance lead facility maybe the time has come to think again.

Mix & Match

 

Since writing my mix & match article for the September KADMAC Club meeting (CLICK HERE to read) we should by now all have received a copy of the new BMFA hand book, which is a big improvement from the old one in many ways.

Within this latest copy there is a section on page 33. item 15.14 Mix & Match. if you are thinking of operating with a MIX & MATCH system please read this along with the air navigation order Article 241. If you cant comply don’t fly.

 

Lipo FIRE

Earlier today it was reported to me that Nick Hemple has had a Lipo fire within his model room which is situated within his house. First reports are that whilst there is extensive damage to his model room the rest of the house has only sustained minor smoke damage and everyone got out safely.

Comment from Nick.
Reading about lipo fires in no way prepares you for the event, apologies to my wife Nancy and a warning to us all. I don’t know if I will trust them, or myself again.
PLEASE TAKE CARE

I think we can all appreciate the sentiments in Nick’s comment and as members of KADMAC we would like to offer any support as needed to  Nick and his family.

A full report will be issued as and when the full facts are ascertained.

nick 1

My first thought after find out everyone was ok, was how many times have I nipped off for my tea or some other reason when charging my lipos, never again

nick 2

This might not be an appropriate time to mention this, but recently a lot of house insurance policies have taken to excluding aero modelling actives. I think this must be a good time to check ours.

If you would like information on Li-Poly use and safety please checkout in our Handbook section of this website.
LITHIUM POLYMER BATTERY SAFETY BOOKLET
written by  Bob Smith

Battery safety

Or Click Here

BMFA Safety Bulletin

Safety Bulletin :- Noise Testing procedure improved guidance

Club Support Officer  posted on 02/10/2015 12:36:00

                     Following a serious injury received when a propeller detached while an aircraft was at full power being tested for noise, recommendations have been issued to help mitigate this risk. These recommendations apply to the element of the test with the model pointing directly at the meter.

1)    Always check the security of the propeller before conducting any noise testing. Guidance on the integrity of multi-bolt attachment of large propellers will be issued following further investigation of the incident.

2)    If possible, use a tripod mounted sound level meter (SLM) with a memory function that can store the maximum A weighted sound pressure reading.

3)    If the SLM operator has to stand in front of the model, use a “catch” net (see picture below) placed at the midpoint between the aircraft and the SLM. We have conducted trials using cricket practice netting 2m by 2m constructed of 50mm (2″) square mesh black polyethylene of 2mm gauge (cost £12.90 inc P&P) . (www.knowlenets.co.uk/leisure/cricket.htm) The trials showed no significant effect on the SLM measurements.

 

FAKE Rx’s!!!!

One of our members has experienced loss of control/connection with his models 2 or 3 times this year, after the 3rd time he sent off his transmitter and all his receivers back to the main UK agent for testing. A few days later to his surprise he received a call from their technician who told him that two of his receivers were fake!!! These Rx’s where brought from what looked like a ligament website and could not be distinguished visually from the genuine factory item. I guess by now you can hear the same alarm bell as me ringing.

 

Both Rx’s were given to Derek Round who as some of us know has considerable experience in building testing and repairing radio systems. He has just got back to me with his first analysis of the situation, please read on.

 

Inspection of two fake Spektrum Rx’s

I’ve just had a look inside! Interesting! No conclusions about anything as yet, but they are both NOT Diversity Receivers. Now over the years, Spektrum have made a great play that the signals from the two aerials are compared, and the best signal (strongest) is used. This is how a DIVERSITY Rx works, and there should be two Rx’s on the board. Quite simply, there’s only one (on each), and the other “aerial” is technically what is called a counterpoise, is connected simply to the ground plane, and it isn’t and wouldn’t do much electrically at all! Just one of the “aerials” would be doing pretty much all the receiving. What it means is that the Rx would be much more susceptible to shadowing or fading due to the lack of “diversity” .

Now, do you remember when I got my 2.4ghz Spectrum Analyzer going, and it became obvious that the Spektrum claim that their system looked for quiet areas of the band and shifted the operating frequency to suit, was actually a load of bull as plainly it didn’t do that at all. I wonder whether this business about diversity Rx’s is a similar claim? It could be, as by using a satellite, that technically would mean you had two Rx’s, and that is a simple definition of a diversity system.

So, perhaps you could put out the word on the website, or elsewhere, that to help this research, that if anybody has any non-working Spektrum (or Fake Spektrum) receivers or satellites, I’d like to investigate them! The state of the case is not important, just the innards.

 

This is not just levelled at Spektrum as we now have two lower end Futaba Rx’s that appear to only be using one of the two aerials. The problem shows up when range checking at an extended distance and the model is rotated, when one of the aerials points towards the transmitter, failsafe kicks in. This was first noticed in an F5D pylon race model at the number one turn when the model momentarily locked with the elevator pulled on. As we have used the same model of Rx’s in other pylon models without any problems, we will be investigating these as well.

 

If you or you know of anyone who suspects they might have a fake Rx’s please let me know and get the item to us asap.

 

Derek Round: round@sky.com

Peter Harvey: peterharvey@keighleymodelflyers.co.uk