Terrible Accident

[lohring]

I'm open to suggestions on the design of a safety loop. The 5.5 to 6 mm connectors work below 100 amps, but the extra set of connectors in series cause power loss, and they get hot. I've had some get hot enough to melt the solder after being connected and disconnected several times. I have experience with a lot of 8 mm connectors, see below. We ran around 100 amps through these connectors. I've run close to 200 amps through them in models. They are very hard to disconnect for a safety loop. Pairs of smaller connectors could be used, but again the extra connectors and wires cause complications.There are industrial high current quick connectors available, but they are way too expensive for hobby use.

Most high amp industrial connections are bolted. Look at a welder or your car battery. People who run serious electric boats use as short wires with as few connectors as possible for minimum loss. Australian and European electric rules once required safety loops. Does anyone know what is used now? The present feeling here as people got experience running electric boats is that safety loops aren't needed. In fact, electric boats are safer than gas or nitro boats since the propeller isn't spinning while the boat is being carried. Of course the operator needs to resist the urge to blip the throttle.

It's been a very long time with modern speed controls since I've seen an electric motor start mysteriously. Maybe you should impound all transmitters until the boat is in the water and after the end of the race. That would disconnect the most dangerous link in model boat racing, the operator. As i and the t-shirt said above, you can make a lot of rules, but the hobby is still dangerous. There's no substitute for care and common sense.

Lohring Miller

 

[moparbarn]

Two thoughts....the RX in a fe boat could be switched, couldn't it? I realize that would not disconnect battery power to the ESC, but it would remove both pilot error & potential radio glitches from either heat or moisture. The other thought (I know, a lot for me all at once!) would be a relay or contactor that the switch would be wired into the control side of the relay. Is there such an animal that would be small& light enough, yet still carry the load we require, at a price that is affordable?

 

[HTV Boats]

The incident that prompted this thread might have been addressed by a safety procedure as Lohring stated. A simple impound or designated table for every transmitter of an FE boat on the water needing retrieval. Want your boat picked up after the heat, put your RX where it can be accounted for. When anyone who has retrieved an FE hull of mine and I am not sure they are familiar with FE, I tell them to treat the boat as if the prop is spinning.

As for "loops", a good idea but maybe less practical for all hull styles. Do you standardize the position on all varieties of hull? As the retriever is looking for and disconnecting the loop is that more risk than just treating it as a running boat in the first place?

I think the dormant TX rule might be the first place to go here.

Mic

 

[moparbarn]

That is a good idea, mic. Simple & effective way of eliminating one possible cause!

 

[lohring]

Below are a couple of safety loop installations on some very nice boats. The connector is the issue. Amphenol Radsok style connectors are the only high amp, moderate disconnect force, connectors I have found. The maximum disconnect force is 15 pounds. The 8 mm size is rated for 200 amps, the 10 mm size for 300 amps, and the 12 mm size for 400 amps. A pin plus the connector cost in the $8 to $26 range depending on size. That compares to $2.50 for a pair of 8 mm connectors rated for around 200 amps. Look at the pictures, buy some connectors and see how a safety loop works. After you race for a season with it report back on your experience.

Do you still think it should be a required safety feature?

Lohring Miller

 

[Hydro Junkie]

Lohring, you do realize you're beating a dead horse and asking to get this thread locked up again, don't you? This was Don's response, in another thread, about why he recently locked this thread:

Since you decided to post asking why it was closed it was done just like others that see the same ending- when members start asking to do so. I said my peace and was done with it but the p/ms and emails about how some lacking FE knowledge just couldn't stop flogging the same thing I had no problem doing so since I felt the same way. The accident was due to stupidity and unsafe actions, not a battery loop that some non FE folks just seem to think it's a cure all for FE safety. If you all want to talk about safety and ways to improve that OVERALL that's fine, I'll unlock it but it's way past time to move on past the battery loop............

If you haven't seen the thread this is from, here's the link:

http://www.intlwaters.com/index.php?showtopic=64072

 

[Kris Flynn]

Original post was about a stupid incident/accident, agree 100%

I guess the Europeans and Aussies just dont push equipment hard enough as safety loops are not an issue (we also only run 1P).

Why not deal with power loss by reducing power consumption and finding efficiencies in other areas.

my 5.5mm connections dont get hot...but I guess I am doing something wrong. Good solder and soldering are key IMO.

why are people against a simple and effective safety feature. ...are you all not over the top with your safey BS over there?

If done correctly it will add one male and one female to your system. If that will strain your setup too much, then you should maybe step back a little and look at the big picture.

Loops are identified with a orange triangle so anyone can identify its location. Anyone rescuing boats will need to be informed of this so they know what to look for. Took maybe a couple of race meetings here to "train" people to pull the loop prior to placing rc boat into rescue craft.

 

[Kris Flynn]

In the end you guys can do what you want, I was just surprised at the huge negativity around safety loops when they have a positive role in making the hobby safer.

have you seen an FE guy change a prop without un taping the cowl to disconnect the battery? Asking for trouble...

Not much different to a gas boater removing the coil lead from the plug...

 

[lohring]

I have run safety loops. All my early boats had them. Has anyone else in this discussion run safety loops? I've only personally witnessed propeller cuts on nitro boats. The only other accidents I've personally witnessed are a gasoline fire, burns from incorrectly connecting batteries, and falling out of the retrieve boat, by far the most common and the most dangerous.

Since few of these involved electric boats, I propose that we outlaw the current ways of powering model boats. Electrics are also more reliable, and safer if you restrict the size and battery. The current rules on size and batteries don't go far enough. The perfect safe and fun racing is pictured at https://www.youtube.com/watch?v=XvwSYB0KYrI. The cost and universal race site eliminates objections to the high cost of boats, the shortage of race sites, and all safety issues. NAMBA could reduce or eliminate insurance costs and we wouldn't need to qualify race sites. The rule book could be greatly simplified.

I'm writing up the proposal for a vote. The only down side is that Ebay would be flooded with outlawed model boats. However, the increased fun would be worth it.

Lohring Miller

 

[DPeterson]

Going on my 15th year now of running electrics. Seems almost all of the safety issues I have seen can be traced to an unsafe practice or procedure. Not equipment related but rather person related.

With that said, my two new electric builds will have the safety loops installed. Partly for safety and partly for convenience. With the loop I can tape up early, I can park the boat in the pit area early and I switch out props during testing times very easily. The added safety is just a bonus. These are of course 1P set ups. I agree that higher performance 2P set ups would be a little more challenging.

When my boats flip on the water and need retrieval I make a point of setting the transmitter down in a safe out of the way place. In many cases it is the distractions that are caused by conversations that can lead to an unsafe act. Best to keep your fingers away from the TX while arguing with your buddy on why your boat flipped.

Whether or not discussing safety leads to an argument, or rubs a few members the wrong way, these discussions have to happen. Period. I am quite surprised these would be stifled. Goes against every Corporate Manufacturing Safety Committee I have been on.

 

[Mark Bullard]

I am still looking for a answer to my question from a earlier post. Does the switch on some ESC's disable them? Or placing a switch inline with the receiver disable the ESC. I understand there was a bad mistake made of handling the boat. But knowing that there could be a mishap with a ESC for some reason we need to be able to disable it. A power loop would work but very hard to do with the current that you are seeing. A simple way would be to have a switch that would disable the ESC's control logic at board level. A simple power disconnect from the battery that powers the main control board of the ESC. All of the DC buss IGBT's or whatever you all call them could still have power on them with no chance of a problem with no control from board. If some of the IGBT's shorted there would be a other problems, like letting the smoke out. But let say that one IBGT shorted. All that would happen would be the motor would lockup in that pole position. This setup would be the safe way of disabling the ESC without a lot of cost.

 

[DPeterson]

Mark

Probably not getting an answer because none of us electric racers have electronic backgrounds. Kind of scary.

Over the years I have seen ESC's lock on and lock off. Probably water related but also electronic related. Not sure I would put trust in an electronic method to dis-connect. The usual, fool proof disconnect method is either un-plug, breaker, fuse or throw switch.

I have also thought about a timer system built into an esc or put in line, that if the esc did not see power for say one minute the esc would shut down and have to be reset before it could be operated again. This then would be a self contained shut down system within the boat. But then again it would be an electronic disconnect and not a true disconnect.

Doug

 

[RaceMechaniX]

Mark,

To answer your question in 99 out of 100 times if you disconnect the receiver power to the ESC, the ESC will remain in a neutral position. It still may be armed, but it would have to see a viable throttle input to spin the motor.

More to your point: when using ESC's with BEC circuits (i.e. no separate receiver battery) disconnecting the red wire from the ESC to the receiver will remove receiver power and should put the ESC in a "neutral" mode. The ESC needs to see a viable signal and ground reference. I am saying this for most common ESC's I have at least worked with. I am sure not every one is like that.

For ESC's with optically isolated inputs (i.e. they need an external receiver battery) switching off the receiver power has the same effect. The optically isolated ESC's have a margin of extra protection over the BEC varieties as the will not arm without a receiver signal.

Many guys running twins or higher than 8S set-ups by default have optically isolated ESC's and most run an external receiver switch just like a nitro or gas boat. These are reasonably safe even when the batteries plugged into the ESC's. when you plug in the receiver loop or switch, the ESC's arm and off you go. If you flip/die/etc when you get to the boat you pull the loop or flip the switch and you are reasonably safe. Common sense should prevail and you should not grab the prop in till everything is disconnected.

My personal opinion is main battery loops are the end all safety solution, but would discourage both seasoned and novice boaters alike. Myself being one of them. I would vote in favor of a switch to disconnect power to the receiver in some form, but would not vote in favor of main battery loops.

TG

 

[Mark Bullard]

Thanks for the answers guys. And I know enough about electronics to be dangerous. But I do understand electrical components and controls of them. I know that the ESC manufactures build them cheap as they can. The fix is simple break the circuit of the main board and the DC buss. This will prevent the ESC from arming. You will still have voltage on the DC buss and this will have power on the IGBT's to the motor. What this will do is stop all control from main board to the firing control of the IGBT's that emulate the phasing of the 3 phase motor. This type of switch or open circuit device will also stop all radio function if you use the BEC circuit from the ESC. This kind of control can be a switch just like we use on our receiver switches. All the manufactures would have to do is bring two wires off the board to be control by connecting or placing switch between them. I myself have not look at a ESC close but bet I could find the connection between the positive side of the DC buss and the main control board. By cutting this connection and soldiering two wires in place of it will allow a way to install a switch.

The one thing about this type of control with the IGBTs powered up is they will not work if they don't have a firing circuit from the main board. They can short out or blow open but in this case the ESC goes up in smoke and the motor still will not run. But the main thing is the ESC would be safe and a lot safer than what everyone is doing now.

 

[T.S.Davis]

I'd be willing to wager that I've retrieved more FE boats than anyone in the US. I've seen the retrieve boat hit one time. It was with in 2003 with an FE rigger on 12 Nicd and an FM radio system. The retrieve boat was on shore and nobody in it. Pretty lucky really. I even remember who's boat it was.

I have seen multiple running motors though. Always from water in the rx. Every time. A boat sitting upside down for too long and fills with water. I've only seen it on boats with a BEC for what ever reason. Weird. Maybe guys building bigger boats with opto speedos are more careful. IDK

So picture a boat on it's lid in the water with the prop buzzing away like a dremel tool. Your the retrieve guy. Got a plan? The safety loop isn't going to help you snag it from the water. You still will have to grab it. Turn it over. Then pull the loop. The few times I've run into it I take someone with me to drive the retrieve boat. Then I grab it on both sides with the prop pointed away. At this point I'm in control. Now I can pull the tape and yank a wire easy enough.

I think calling them bombs is a little dramatic. At least we aren't carrying around flammable liquids. There are entire NFPA standards written for those. haha

The safety loop is a good idea for the convenience Doug described but making everyone have one wont do what some think they will. Some point to Europe as an example for safety. They can do safety loops there so we should too?......... No offense but they keep racing during the retrieve. Should we adopt that too?

The reality is that we're playing with dangerous toys. Guys ride dirt bikes. If they're complacent they get hurt. If we don't respect the danger we are going to get hurt. Respect the fuel or you could get hurt. Respect the razor sharp hardware or you could get hurt. Respect that an FE still has potential energy even though the prop isn't spinning or you could get hurt.

We can't make enough rules to protect us from ourselves. I guess if I stay home in my house maybe I could be the very most safest guy on the planet.

 

[T.S.Davis]

Really want a safety game changer for boating? Get all the manufacturers of radios to make waterproof RX's. Most glitch I see are water related. I know, keep them dry. Well duh. Nobody gets water in there on purpose.

I still can't understand how Futaba is behind Spektrum and Airtronics on the waterproof thing. I know we're only a marketing speck of dust but how hard could it be really?

 

[Don Ferrette]

I'd be willing to wager that I've retrieved more FE boats than anyone in the US. I've seen the retrieve boat hit one time. It was with in 2003 with an FE rigger on 12 Nicd and an FM radio system. The retrieve boat was on shore and nobody in it. Pretty lucky really. I even remember who's boat it was.

I have seen multiple running motors though. Always from water in the rx. Every time. A boat sitting upside down for too long and fills with water. I've only seen it on boats with a BEC for what ever reason. Weird. Maybe guys building bigger boats with opto speedos are more careful. IDK

So picture a boat on it's lid in the water with the prop buzzing away like a dremel tool. Your the retrieve guy. Got a plan? The safety loop isn't going to help you snag it from the water. You still will have to grab it. Turn it over. Then pull the loop. The few times I've run into it I take someone with me to drive the retrieve boat. Then I grab it on both sides with the prop pointed away. At this point I'm in control. Now I can pull the tape and yank a wire easy enough.

I think calling them bombs is a little dramatic. At least we aren't carrying around flammable liquids. There are entire NFPA standards written for those. haha

The safety loop is a good idea for the convenience Doug described but making everyone have one wont do what some think they will. Some point to Europe as an example for safety. They can do safety loops there so we should too?......... No offense but they keep racing during the retrieve. Should we adopt that too?

The reality is that we're playing with dangerous toys. Guys ride dirt bikes. If they're complacent they get hurt. If we don't respect the danger we are going to get hurt. Respect the fuel or you could get hurt. Respect the razor sharp hardware or you could get hurt. Respect that an FE still has potential energy even though the prop isn't spinning or you could get hurt.

We can't make enough rules to protect us from ourselves. I guess if I stay home in my house maybe I could be the very most safest guy on the planet.

THANK YOU Terry.

 

[DPeterson]

Terry and I agree on something. There is a ray of hope.

Mandating safety loops would do like some other rules. Gives an illusion of safety. In fact I believe loops may even increase the risk of danger. While the retrieval dude is search for and pulling on the loop he takes his mind off of the propeller. Not good. Concentration is the key here.

Good point on the water proof receivers. Although I have not had an issue with my Futaba's in my balloons.

After hashing out this subject once again, I will be implementing in my club a designated safe box - radio impound for any electric boat while being retrieved. It will be located very close to the driver stand and retrieval area. Very easy and painless. This at lease takes out the risk of radio operator error while retrieving.

Doug

 

[Don Ferrette]

After hashing out this subject once again, I will be implementing in my club a designated safe box - radio impound for any electric boat while being retrieved. It will be located very close to the driver stand and retrieval area. Very easy and painless. This at lease takes out the risk of radio operator error while retrieving.

I think what Doug is suggesting is a VERY good idea.

 

[moparbarn]

After hashing out this subject once again, I will be implementing in my club a designated safe box - radio impound for any electric boat while being retrieved. It will be located very close to the driver stand and retrieval area. Very easy and painless. This at lease takes out the risk of radio operator error while retrieving.

I think what Doug is suggesting is a VERY good idea.

What Lohring suggested back on post #61 IS a very good idea, Doug implementing it is an EXCELLENT idea!! Something I'd like to implement as a d-12 rule, although we should start doing it now - rule or not (-;