A new worry for me- are Lipos safe?

[Simon Chaddock]

Surely its all a matter of design and location of the heavier components.

None of my home designs, scale or not have to have their wing removed to install the batteries. Even the biggest where its batteries are located inside the wing and accessed via a top hatch.

Yes it restricts the range of battery weights possible but they are designed to meet their design performance at a particular weight.

[Paul De Tourtoulon]

20 hours ago, leccyflyer said:

It depends on the model configuration and how the battery packs are accessed. I certainly couldn't connect the battery pack up on my Gladiator in less than 10 seconds.

 

The likelihood of me visiting your club is somewhere between none and zero, but I don't believe  that any of the many clubs that I have visited and flown at in the last thirty years has a rule that the batteries must be connected only on the runway.

 

Just out of interest, with your glow engines, do you take them to the runway and only then attempt to start them?

After I kicked the wasp's nest, I expected a few more reply's, 🤐 safety of any model with a propeller is keeping behind it, this morning I was fiddling with my petrol concerted Saito 150, I made a venturi up to see whether it would boost up the power.

While warming it up, as usual, I was behind the prop.😇 second hand yellow cone for sale,,,

 

I am a glow and petrol ' whisperer', they start up all on their own.😅

[john davidson 1]

23 hours ago, PatMc said:

It might be worth painting the box white or silver if that wouldn't make it an eyesore to the garden management person. 

Had a B and Q voucher so ordered a metal box as Leccy suggested , blooming site accepted the voucher but no discount at the  checkout. My site is in full sun all day so thinking of using the foil and foam used for behind radiators externally.

[leccyflyer]

Yes John, we found the same, tried to apply a B & Q voucher, but found at Checkout that it's not valid since this is an item that doesn't come direct from B & Q and it isn't available in the shop. My flat pack was waiting for me when I got back from flying last night.

[leccyflyer]

21 hours ago, Paul De Tourtoulon said:

After I kicked the wasp's nest, I expected a few more reply's, 🤐 safety of any model with a propeller is keeping behind it, this morning I was fiddling with my petrol concerted Saito 150, I made a venturi up to see whether it would boost up the power.

While warming it up, as usual, I was behind the prop.😇 second hand yellow cone for sale,,,

 

I am a glow and petrol ' whisperer', they start up all on their own.😅

Nasty. Glad that you escaped without any harm done.

 

Taking it from your reply that you do actually start your glow engines before carrying the model to the runway then?

[Neil James]

On 31/07/2023 at 10:37, leccyflyer said:

Unfortunately no easy access to power - key thing is to monitor how hot the inside of the unit could get in summer and, as I said, I'm being careful to locate it out of direct sunlight. If it stays below 25 degrees C then I'll be quite happy with that.

I use one of these in the shed, it’s battery powered and you can read the device from a distance via Bluetooth. That might not work in a metal box but assuming you’re not looking for real time alerts it’s very quick to download the stored data to your phone. At least then you will know the max and min temperatures.

 

https://www.amazon.co.uk/SwitchBot-Temperature-Thermometer-Hygrometer-Bluetooth/dp/B09QBR7XJD/ref=sr_1_2_sspa?crid=2OF7ASQY2AXQI&keywords=Switchbot&qid=1690967123&sprefix=switchbot%2Caps%2C212&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

[Paul De Tourtoulon]

1 hour ago, leccyflyer said:

Nasty. Glad that you escaped without any harm done.

 

Taking it from your reply that you do actually start your glow engines before carrying the model to the runway then?

Yes I do, the table I start my small ic planes on is next to the taxiway, my 15cc + planes are started on the taxiway, and stopped on the taxiway.

 

My only electrics are gliders and drones and yes, I plug the battery's in on the runway as I preach.

[SIMON CRAGG]

I never charge at home, always at the field. Put up solar panel to keep leisure battery topped up, connect up and put on charge. Waffle to other blokes, prep site, come back and lipos charged.

[John Lee]

I never charge at the field, always at home. Arrive at field & immediately fly. Won't waffle to the other blokes until I have a couple of flights under my belt. Takes all sorts!

[leccyflyer]

15 minutes ago, SIMON CRAGG said:

I never charge at home, always at the field. Put up solar panel to keep leisure battery topped up, connect up and put on charge. Waffle to other blokes, prep site, come back and lipos charged.

I never charged at home either - always charged at the field, Nowadays though, with a 90 minute -2 hour drive to the larger club field, making a three and a halt to four hour round trip and no viable mechanism for charging en route, charging at home provides a more attractive option. My recent workshop build has also given the option to charge at home in a safer environment than within the house, which I had never had before. Still take lipo charging super seriously though and try to put as many safety systems in place as possible.

[Martin Harris - Moderator]

1 hour ago, John Lee said:

I never charge at the field, always at home. Arrive at field & immediately fly. Won't waffle to the other blokes until I have a couple of flights under my belt. Takes all sorts!

I charge at home, arrive at the field, fly or waffle as the mood takes me, recharge on our solar charged club facility, fly, waffle repeat...

[Andy48]

On 30/07/2023 at 09:22, Jon - Laser Engines said:

 

you absolutely need a restraint, more so than for an ic model as an ic model will not just start itself. 

 

At my old club we mandated all models were restrained after more than a few incidents where electric models decided to exit the pits of their own accord. Fortunately other safety protections in the form of our field layout prevented any serious incidents, but we didnt want to take any chances. 

Almost all my models have an arming plug (except a couple of foamy EDFs, and I have an almost foolproof tx switch for those). I walk onto the flight line, arm the model, and then check the control functions. When arming, the model is pointing away from the pits and I stand with the rear fus between my legs so it cannot accidentally take off.

I only use a restraint when testing a new model to ensure all the safety settings function correctly and the range check is satisfactory.

With the arming plug, there is just no way the model can become live between inserting the battery in the pits and walking out to the flight line.

[MattyB]

3 hours ago, Andy48 said:

Almost all my models have an arming plug (except a couple of foamy EDFs, and I have an almost foolproof tx switch for those). I walk onto the flight line, arm the model, and then check the control functions. When arming, the model is pointing away from the pits and I stand with the rear fus between my legs so it cannot accidentally take off.

I only use a restraint when testing a new model to ensure all the safety settings function correctly and the range check is satisfactory.

With the arming plug, there is just no way the model can become live between inserting the battery in the pits and walking out to the flight line.

 

Holding the model in the hands or with the tail between your legs does count as an effective method of restraint as per the BMFA handbook, so you are actually restraining your model just fine! 😉 I do agree there is no need to restrain models with a physical arming plug prior to that plug being inserted though.

Edited August 2, 2023 by MattyB

[Bruce Collinson]

19 minutes ago, MattyB said:

 

Holding the model in the hands or with the tail between your legs does count as an effective method of restraint as per the BMFA handbook, so you are actually restraining your model just fine! 😉 I do agree there is no need to restrain models with a physical arming plug prior to that plug being inserted though.

No need, other than for the benefit of all the other members who can clearly see that the model is safely restrained.

 

It reminds me of an episode thirty five years ago when one elderly gun on a shoot entered the gun bus with his shotgun unbroken.   Amazing how fast you can get out of the side windows of a Transit van.   When taken aside for a chat about basic safety, his defence was "I always unload first".   Ours was, how the hell are we supposed to be able to know that?

 

A broken gun is a safe gun.   A tethered model is fundamentally safe and visibly so, irrespective of Tx throttle cuts (mine is on a toggle switch), arming plugs or indeed whether or not it contains a battery at all.   NLMFC is producing proper metal restraints for purchase by the surprisingly large number of members who appear to lack them.

 

It is also tightening the protocol on pilot box etiquette (see Geoff S's thread) after an episode of failed communication between two pilots, coincidentally at around the time the recent fatality was publicised.   In any wind or with ic planes nearby, if the pilots are out of the box then somebody will fail to hear somebody else, and therein lies a potential accident.

 

The dividing line between safety and nanny state-ism is a fine one.

 

BTC

[MattyB]

3 hours ago, Bruce Collinson said:

No need, other than for the benefit of all the other members who can clearly see that the model is safely restrained.

Fair enough, I agree it’s optimal and should be done wherever possible, but I’ve met plenty of people who use isolation plugs in part because they have models that can’t easily be tethered when installing and connecting a battery. Many multirotors and some e-gliders are good examples of this. I personally don’t use isolation plugs, so I always physically tether whenever I can, but I do have a couple of soarers which are essentially impossible to tether securely whilst connecting the battery from behind bless you have a second person to hold the model.

[Bruce Collinson]

I'd belatedly make a distinction between tethering whilst installing and connecting a battery  (anything small or with a hatch underneath (like my Acrowot) cannot realistically be tethered) and tethering after the model is live, as opposed to relying on a second protocol, arming switch, throttle cut etc.   The latter satisfies the pilot; the former reassures the other pilots.   There's nothing worse than watching someone operating or flying and feeling twitchy about it and it seems to happen more often with electrics, at least on the ground.

 

Therefore I think we are in agreement.

 

BTC

[Zflyer]

I have to say that I rely on my throttle cut switch. But what really scares me is seeing people lean over the prop when connecting/disconnecting batteries!!

[PDB]

18 minutes ago, Zflyer said:

 But what really scares me is seeing people lean over the prop when connecting/disconnecting batteries!!

As someone on blood thinners I’m very concerned about the prop catching me. Every model I have is restrained and it may look odd but when disconnecting the glow starter or a battery I do it walking round and approaching from behind the prop, never from the front reaching over.

[MattyB]

14 hours ago, Bruce Collinson said:

I'd belatedly make a distinction between tethering whilst installing and connecting a battery  (anything small or with a hatch underneath (like my Acrowot) cannot realistically be tethered) and tethering after the model is live, as opposed to relying on a second protocol, arming switch, throttle cut etc.   The latter satisfies the pilot; the former reassures the other pilots.   There's nothing worse than watching someone operating or flying and feeling twitchy about it and it seems to happen more often with electrics, at least on the ground.

 

Therefore I think we are in agreement.

 

Yep, agreed - the foamie Acrowot is a great example of one that you just can't realistically tether when installing the battery. TBH though I can't think of many situations where I would install a battery in a model then physically tether it; a solo range test is pretty much the only one. No electric model should sit in the pits; even at the flight line it shouldn't have the battery connected unless the intent is to fly within the next few seconds.

[aidan mcatamney]

14 hours ago, PDB said:

As someone on blood thinners I’m very concerned about the prop catching me. Every model I have is restrained and it may look odd but when disconnecting the glow starter or a battery I do it walking round and approaching from behind the prop, never from the front reaching over.

Yes absolutely correct.   

[leccyflyer]

18 hours ago, MattyB said:

Fair enough, I agree it’s optimal and should be done wherever possible, but I’ve met plenty of people who use isolation plugs in part because they have models that can’t easily be tethered when installing and connecting a battery. Many multirotors and some e-gliders are good examples of this. I personally don’t use isolation plugs, so I always physically tether whenever I can, but I do have a couple of soarers which are essentially impossible to tether securely whilst connecting the battery from behind bless you have a second person to hold the model.

Yep - I have one electric glider where it is impossible to tether or restrain the model, other than with a comforting hand on it's fetlocks whilst the battery is connected and the wing attached. Why doesn't it have a hatch, some may ask? Well it's a fibreglass fuselage with the built up wing restrained by a wing bolt at the rear of the wing seat, from NiCd days and to put in a hatch, without severely weakening the rather slim nose is not an option that I would consider easily achieved, or even particularly desirable. It's not a model that I have any great affection for, and don't anticipate the effort required in ensuring that such a modification wouldn't compromise it's structural integrity, for the few flights it gets in a season. It's a bit lightweight to do away with the motor all together ant put it to work on the slope, though I guess that could be an option.

[leccyflyer]

Following up with progress on the lipo bunker for storage, it's all assembled now from the flat pack, about 50 nuts and bolts and some pressed sheet steel panels so thin that if they weren't painted, with a monomolecular layer of paint, they would be transparent. It's a bit flimsy, but it went together okay and is still a bit wobbly, due to the materials used and the minimal stiffening included, plus it needs some self tappers adding to the periphery as the final stage  once it's lined out - you certainly wouldn't want to sit on it. As pointed out I can see that it certainly wouldn't be airtight, so no worries about having to drill any vent holes. The holes in the bottom corners are big enough to admit our vole population, so I'll need to seal those off with some 6mm wire mesh, leaving them free to vent in the event of an incident.

 

Having got the thing all together and able to measure, I have just enough room to completely encase my three in-use lipo bags inside the space left if all six sides of the bod is treated to 100mm of the same rigid foam insulation which is doing such a great job with temperature stability in my workshop. That cuts down the volume in the box dramatically. It doesn't have room to fit my pair of Sentry fire safes in there, which currently house some retired lipos at long term storage voltage. If I didn't insulate the box quite so well, I could have room for those fire safes, but that isn't really the mission here. Those will either have to stay in the existing cabinet or, finally bite the bullet and dispose of those retired lipos, which is the right thing to do. So, three sheets of insulation are ordered and will be delivered tomorrow. I'll aim to get those installed, but not stuck in, then paint the outside of the unit something other than the solar-absorbing dark grey colour. Once that's done I'll put it outside in the proposed shady location and monitor the temperatures for a few days. If that works out okay, the in-use lipo bags can go to their new home.

[john davidson 1]

My bunker was waiting for when I came home an hour ago but my intention is to fit it out as a waterproof box for charging , not for storage.  I don't worry about storage but do about charging in my wooden garage, even though I do it on  a large concrete slab.

[leccyflyer]

My bunker is just about ready for painting and temperature testing. So probably time to put a few piccies up.

 

The bunker comes in a flat pack and is constructed of quite flimsy, pressed steel panels which, rather annoyingly are painted the perfect colour inside, but that dark anthracite on the outside, which will need to be dealt with. It goes together relatively straightforwardly, but some care is needed with the positioning of slots vs holes on the sides - the self tappers need to go through slots on the outside to give some leeway, then into the holes on the inside, to grip. Most of the construction used 4mm bolts, with plastic washers and nuts on the inside of the frame. It's a two person job to fit the lid, as it needs to be fully supported when fixing the hinges, The two rams to hold the lid up are screwed into the lid and the accepting frame inside the box - which was a bit tricky for me as I couldn't find my 12mm spanners anywhere, until right after I'd finished!

 

 

Anyway, once assembled, I lined the inside framework with some ordinary expanded polystyrene packaging, to fill the gap imparted by the ridged structure of the steel sides. That gave a decent surface for the 100mm thick KIngspan panels to be inserted, cut to size and a snug fit. None of this is stuck down in any way, so it could be easily removed if necessary - a good tight fit ensures that it can't move. The box itself is not airtight, there are small holes in each corner. 

 

 

 

 

After the Kingspan insulation is all installed I've added a lining of flame retardant 2mm Correx from some remnants I had from my model rack project. I'm under no illusion that this would resist a lipo fire, but its main role is to ensure that there is no possibility of a short from a lipo contacting the aluminium foil of the Kingspan. The Kingspan insulation needs to be cut away to allow the movement of the lid supporting rams and there is also a deliberate gap left in the top section of the front panel to allow the lock mechanism to operate. The final piece of Kinspan is fashioned into a lid, covered in the 2mm Correx and a snug fit. To allow for venting of gases in the event of a lipo fire six 19mm holes are drilled through that top piece of KIngspan, which should be more than sufficient to avoid build up of sufficient pressure to turn the box into shrapnel.

 

 

There's enough room in there for my three lipo bags and a couple of Lipo Sacks, so all of my in-use lipos can be housed there. Only after some temperature tests though.

Edited August 7, 2023 by leccyflyer

[john davidson 1]

Put legs on my one so it is a comfortable height, now stripping the clear sticky plastic so I can paint with solar reflective paint left over from another project, then install a shelf, drill /cut hole for electric cable