It's also important to understand that there is a lot of technology outside of the battery itself that supports its operation that can also fail, and changing cell type does not eliminate that element.
Lets remember there are several billion lipos out there in operation every day and increasing in number every hour. Failure is rate is rare Inspection of failures also shows that a good percentage are due to misuse and abuse. People are flying with petrol bombs all the time and on occasion they have caught fire as well. For the curious, it's worth searching up on the primary reasons for Lipo failure. You might be surprised. > On 29 Sep 2017, at 8:02 am, [email protected] wrote: > > > From your own included links Bernard; > > > > The FES battery packs are removable for charging remotely from the sailplane. > Each FES battery pack is built up from 14 Superior Lithium Polymer Battery > (SLPB) cells, connected in series and contained within a carbon fibre battery > box with a machined aluminium alloy cover plate/heatsink. The maximum total > voltage for each battery pack is 58.3V, giving a maximum voltage of 116.6V > for the assembly of both battery packs connected in series. > The capacity of each SLPB cell is 41 Ampere-hours (Ah), providing a total > capacity for each FES battery pack of 21 kWh, or 4.2 kWh for both battery > packs connected together. Each FES battery pack has a mass of 15.7 kg. > > > > > Regards > > SWK > > > ----- Original Message ----- > From: > "Discussion of issues relating to Soaring in Australia." > <[email protected]> > > To: > "Discussion of issues relating to Soaring in Australia." > <[email protected]> > Cc: > > Sent: > Fri, 29 Sep 2017 06:32:59 +0930 > Subject: > [Aus-soaring] FES fire in the UK > > > Good morning all > > This was sent to me over night by a German friend of mine. > > As you can see, no mention was made of the type of battery used here. > From my visits to the AERO trade fair I know that some manufacturers use LiPo > Batteries. > They have the best power to weight ratio but they are known to be extremely > dangerous. > I will attempt to find out if this type of battery was installed in this > glider. > > Kind regards to all > > Bernard > > From UK, newspaper report: > > > > The Air Accidents Investigation Branch has made a safety recommendation after > a sailplane burst into flames shortly after landing in Parham Airfield. On > August 10, 2017, the glider sailplane set off from the airfield between > Storrington and Pulborough at 10.21am for a flight lasting approximately two > hours. The glider was flown normally to a smooth touchdown, according to the > AAIB, until the pilot heard an ‘unexpected noise’. The AAIB report said: “As > the glider slowed during the ground run, the pilot smelled burning and the > cockpit filled with smoke that was moving forwards from behind the pilot’s > head. “He vacated the cockpit normally, without injury, and observed that the > Front Electric Sustainer (FES) battery compartment cover was missing and that > smoke, followed shortly by flames, was coming from the battery compartment. > “The airfield fire truck arrived promptly and an initial attempt was made to > extinguish the fire using a CO2 gaseous extinguisher, but this proved > unsuccessful. “Aqueous film-forming foam (AFFF) was then sprayed into the FES > battery compartment and the fire was extinguished.” > > > The pilot was the only person on board the glider, according to the AAIB. > > He did not report observing any warning messages or illuminated LEDs, when > asked by the AAIB, although his attention was drawn outside the cockpit > during landing. > > The AAIB report found existing FES battery installations ‘do not provide > sufficient warning’ to a pilot of a fire. > > As a result, the AAIB made a safety recommendation that ‘all powered > sailplanes fitted with an FES system, must be equipped with a warning system > to alert the pilot to the presence of a fire in the FES battery compartment’. > > The AAIB investigation confirmed the ‘origin of the fire’ was the forward FES > battery. > > The report added: “Its battery box was ruptured along the rear left corner > and the battery assembly was heavily fire damaged. > > “The rear FES battery box suffered from external fire damage although the > internal components were only slightly damaged and the cells remained charged. > > “The FES battery compartment was heavily fire damaged. > > > > see also > > https://www.gov.uk/aaib-reports/aaib-special-bulletin-s3-2017-on-hph-glasflugel-304-es-g-gsgs > > http://www.front-electric-sustainer.com/news.php > > http://publicapps.caa.co.uk/docs/33/20170906EASAAD20170167E.pdf > > > > > > > _______________________________________________ > Aus-soaring mailing list > [email protected] > http://lists.base64.com.au/listinfo/aus-soaring
_______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring
