Warning: RC is a dangerous hobby

[Mad Ax]

Is it, really?  Well, if we discount battery fires, which are obviously something we all need to be aware of (especially if we use LiPos), it's generally not that dangerous.

But that should not breed complacency.  All too often I get lazy - assuming my car will be perfectly safe with the Tx turned off, because it's a modern radio with failsafe.  I made this mistake just last weekend.

I'd gone to a big rig meet, and took my Globe Liner with me.  This has a modern radio (FlySky, to be precise) and a modern control unit by Beier.  I was pretty sure I'd tested the "radio off" functionality at home, so when I got my rig parked up on the layout, I flipped off the transmitter.  The reason being: after 30 seconds of inactivity, the FlySky FS-i6 Tx emits a really annoying warning sound.  I get that if you're flying (which is what it's designed for) you'd be unlikely to not provide an input for 30 seconds, but the radio is a cheap and reliable way into multi-channel stick for surface, too.  In particular, my big rigs will often be parked up for several hours at a time.  That incessant bleep is infuriating.  I really should rig up a switch for the speaker so I can shut it off safely, but I figured my truck would be fine if I just powered off the Tx.

In fairness, the truck didn't race off anywhere and do thousands of pounds of damage to other people's trucks.  I guess I was lucky.

When I came back to it an hour later, it wouldn't start.  The Tx wouldn't recognise the Rx at all.  I figured the battery had gone flat, so I pulled the truck off the layout and changed it.  Initially it bound and started up, but then went off again.  I could see the reported voltage on the Rx dropping from the moment it was switched on, like something was putting a huge draw on the battery.  Then I noticed a bit of heat on the back of the Beier - had it really been overloading for the last hour..?  That's a £300 unit - I'd be unhappy if it was toast!

In the end, after plugging and unplugging lots of components, I eventually discovered the problem to be the steering servo.  Sure enough, it was really hot.  It actually still works (in that it steers OK) but pulls way too much current even at idle, and causes the battery voltage to drop off and the Beier ESC (which is thankfully LiPo safe) to shut off.

The cause of this was that I hadn't properly configured the failsafe.  For some reason it needs to be configured manually each time a new Rx is bound.  In the default position, the receiver will receive full left lock on the steering channel when the Tx loses connection.  Obviously that was trying to turn the servo way past its limit, which caused it to get hot and damage itself internally.

So, the main damage was just to a cheap servo.  I was able to swap in the gearchange servo and lock the transmission in 1st gear for the rest of the day, so I could continue enjoying my Globe Liner, and I've got enough old servos here that I can fully repair it easily enough, but even so, this is a lesson that someone with my experience and attention to safety should know better: NEVER turn off the Tx before the Rx.  No matter what failsafes you've got (or think you've got) in place, you can't guarantee how the vehicle will respond.

[Mad Ax]

But - it gets worse.

Last night it snowed, so I went out to get the Clod Buster running for a quick blast in the slush before it all melted.  A few months ago my FS-i6 Tx got waterlogged and died, so I replaced it with a new one, but haven't got around to setting up all my cars again.  Since the Clod only has ESC and steering, I figured it would be better to run it from the GT-5 wheel handset.  It's a Turnigy model, but fully compatible with the FS-iA6 receiver used by FlySky transmitters, so binding and running should have been easy.

I say should have.  Does anyone else find that sometimes, FlySky receivers just refuse to bind?  I find it can take several attempts to get it running.  Also, as I often point out when recommending FlySky radios, they can be quirky - one quirk being, even after the Rx is bound, it won't actually respond to the Tx until the bind plug has been removed.  I don't know why this feature exists (maybe to force users to remove the plug before using the vehicle, then leaving it in a ready-to-bind state next time it's turned on?  I've actually done that with Spektrum radios before, so maybe it's not a bad thing).

Well, it took me more than a few attempts to get this one to bind.  I tried, tried, and tried again.  After about 6 goes it told me it was bound, but still wouldn't work.  Then I remembered that I had to pull out the bind plug before it would work, so I reached over, took hold, and tugged it out.

Meanwhile, my 7-year-old had wandered into the workshop to see what I was doing.  She was standing right next to me when the truck suddenly and without warning went full throttle and launched itself off the workbench, right into her face.

This would be bad enough if it was a touring car or a buggy, but the Clod is a heavy old truck, and its reduced gearing means it gets up to speed real quick.  It hit her hard enough to throw her back into brick wall before they both landed on the floor.

We were really fortunate that no serious damage was done - a little cut to her left eyebrow and a sore nose that stopped hurting 10 minutes later, but it could have been so much worse.  Whatever caused the truck to go full throttle was only a glitch, and it had stopped running by the time it hit the ground.  I've had a clod-based truck go full out-of-control before, and with those big wheels spinning like crazy it's like trying to catch a cornered fox.  7-year-olds are tougher than they look, but I wouldn't want my arms or fingers getting sucked in by those big tyres.

I've absolutely no idea what caused it.  In retrospect, the channel assignments between the FS-i6 10-channel stick controller and the GT-5 wheel controller are probably different, and it could be that the ESC is plugged into a rotary channel, but if that's the case it would have kept spinning, right?  And the stock TEU-106 ESC shouldn't have activated if the throttle wasn't at neutral when it bound.  But whatever, it went out of control and shot off that bench before I even knew what had happened.

There's a lesson to be learned here.  ALWAYS immobilise a vehicle before working on the radio system.  It's easier said than done with a clod, because those big wheels want to interfere with regular car stands, especially as all 4 of them can steer, and might just do that if the radio glitches.  Plus the weight of the tyres can cause the truck to tip off a stand by inertia alone, even if the wheels aren't touching anything.  But I've got to look into that, and come up with a Clod stand that will hold it safe when I'm doing stuff like this.

With more and more big-wheel trucks becoming common, especially the 6S Arrma trucks and the X-Maxx, it's not a far cry to imagine this sort of thing happening in households all the time.

I remember when a friend turned on his 1st-gen E-Maxx a long, long time ago, when it had a 27MHz radio system.  He hadn't checked the frequency, and I was on the same crystal.  His truck went full throttle, raced away from him across the park, hooked my ankle form under my, ran over my Dark Impact and broke the carbon shock tower, before piling head-first into a huge rock and snapping the chassis in half.  Modern radios may be way, way better, but they're far from infallible, especially when we swap away from the original fitted equipment.

Heed my warning!

[Kpowell911]

Hope your 7 year old is on the mend, as you say couldve been a lot worse. 
 

Regarding the Flysky stuff. Only time Ive struggled to bind is when the receiver firmware needed updating

[Gebbly]

Thanks very much for the hard learned lessons. I shall try and remember them.

41 minutes ago, Mad Ax said:

NEVER turn off the Tx before the Rx

I hadnt heard this before.

42 minutes ago, Mad Ax said:

default position, the receiver will receive full left lock on the steering channel when the Tx loses connection

Looks like important things to always remember and check each time I set up a new car. I must remember to double check what a given receiver will do if it loses signal from the transmitter. I remember my old hotshot when I was a kid, if it lost signal or the battery was low it just shot off in a straight line and you had to hope hit something soft.

[Sogogi]

Thanks for sharing your experience.

I cannot say for sure, but from my personal experience, ive had some hiccups which led me to invest more in main stream more reliable tx/rx set which would have better /more robust failsafe feature. I remember more than a decade ago when I first experienced brushless with 3s lipo and due to tx/rx glitch, it hit the curve at full speed. Car broke but that was it.. it is scary. Imagine that happening with larger scale (it was 1/18th scale for me) , i cant imagine…

Tamiya manual always says tx on first, but sometimes i forget.. though latest futaba rx never had issues.. but trying to be always cautions. 

[alvinlwh]

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[Kowalski86]

Thank you for the warning, I made this mistake with a TT02 a few months ago.

I go to turn it on (not realizing that it hadn't been bound to my receiver), it takes off at full speed (which wasn't quick with the kit 17t pinion), it jumps the neighbors driveway, drives underneath their car, then stops once it ends up in the grass.

Thankfully, the only damage to anything was some scuffs on the bodyshell.

[Otis311]

I have become pretty lackadaisical with Tx on first and off last. Between my modern Futaba receivers and ESC's that won't arm, I really just threw all that out the window. I don't bother with failsafes anymore, not since my nitro days many years ago actually. Even still I don't feel comfortable leaving the Rx on by itself for long periods of time, your Globeliner story gave me some anxiety. But you did everything right and had the best intentions, the fail safe just screwed you. Something that has been causing glitching recently is running analog servos with the radio system set to digital mode. That is something I tend to double check now when changing between cars in the transmitter.

[rich_f]

Sorry to hear about your incident, but glad it wasn't too bad in the end. 

Being someone who never moved away from using 27MHz AM radios, I wouldn't dream of turning off the transmitter first! Maybe this explains why some people never consider it to be a problem anymore - maybe they've never used an old-style radio. 

Even if you've never had it told to you explicitly, it makes sense that the transmitter should be the last thing you turn off, otherwise there's nothing in positive control of the car - you are only relying on whatever failsafes the designer of the electronics thought of, and that they are working as intended. Surely it's just safer to leave the tx off switch until last...

[OldSchoolRC1]

Ouch! Glad to hear your daughter is ok! 

Loss of TX is no joke. I was racing my old 1/8 Duratrax Axis nitro buggy many, many years ago at the track, and coming down the front stretch and full throttle I bumped my radio on the drivers stand and apparently my battery door wasn't latched properly. All the AA's fell out, and all of a sudden i have a 9lb 40+ mph missile at screaming at full RPM and running out of control. Jumped the track, sailed out of the parking lot, across the field, across a busy 4 lane highway and ended up in a pond on the other side of the road.  Somehow it never hit anything (and made it across the highway in 1 piece, Frogger would be proud) but I was absolutely terrified of taking someone (or something) out. You can believe I made sure nothing like that ever happened again. 

[one_hit]

Yeah I made the same mistake on my 1/8 nitro buggy. Switched off my transmitter, so throttle servo applied full brakes. I placed the buggy on the pit table and chatted with the guys at the track. When I went back, throttle servo was dead. RIP Savox HV digital high speed, high torque servo 

[Wooders28]

Wow!

Hope she's okay, and no lasting Tamiya fears.

 

On 3/2/2024 at 4:07 PM, alvinlwh said:

I had turned on a TX set to the wrong car once, and when I turn on the car, it went full throttle. Luckily I was still holding onto it and can quickly turn it off. Which is why I always insist on switched ESC. I know some cut off the switch as it is safer to unplug the battery but...

 

I've done this with mine, when my Sanwa (meant to be one of the top radios?) was set to the wrong model, plugged the battery in on my Mid, and...

Not sure why they do it, it shouldn't even be talking to the receiver to matter about calibration points,  and should stop if no signal! 🤷‍♂️

[ADRay1000]

this thread reminds me of when I was about 10,  my lunchbox with an msc took off while it was on my lap facing me. I was wearing shorts and the inner sidewall of tire burned a hole in my knee. 

[skom25]

1 hour ago, Wooders28 said:

Wow!

Hope she's okay, and no lasting Tamiya fears.

 

 

I've done this with mine, when my Sanwa (meant to be one of the top radios?) was set to the wrong model, plugged the battery in on my Mid, and...

Not sure why they do it, it shouldn't even be talking to the receiver to matter about calibration points,  and should stop if no signal! 🤷‍♂️

Same here, also with Sanwa. It was set to correct model, but it seems that I switched On ESC too fast and something went wrong. 

I happened two times. First time when RC was inside car, so it ran just for a moment.

Second time could be much worse! I did maintenance and wanted to check electronics. Car was on desk on front of me. I switched it On but in last moment, decided to pick it up. It was good decision, because half second later it was on full throttle. I had luck, because I think heavy buggy on full throttle on chest and face can cause some damage.

RC is safe to the moment when it is not. It is similar to cycling. I did many kilometers for few years, totally without issues, despite I have rather aggresive style of cycling. One day on road bike, both tires lost grip and I was sliding on asphalt for about 5 - 10 meters.

[alvinlwh]

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[87lc2]

Hope your daughter is OK!  I certainly wouldn't want to be smacked in the face by a Clod    Tough kid!

Funny you posted this, I had a similar experience at a race this weekend with the monster trucks.  All of my trucks are on the same Futaba transmitter and I've never had an issue switching between models, turning trucks off, etc.  Not sure exactly how it happened, but a truck was called up to race that I wasn't expecting (guess I forgot where we were in the bracket progression) so I quickly turned it on and got it out on the track for a warm up lap.  About 10 seconds in a heard a bunch of commotion in the pits and apparently I forgot to turn the previous truck off and it went flying off the pit table and across the room.  It was an LMT with a 4000kv 3665 motor so you can imagine that thing just took off    Luckily it was stopped by a pit bag against a wall so no damage to other trucks, people, kids, dogs, cats, etc.   What was funny about it was when I was on track with the other truck I thought the motor sounded extra healthy, turns out I was just hearing the same power system in stereo in the background being controlled by the same trigger finger that was driving the truck on track.  Could have turned out much worse and I would have felt terrible if it were to hit a person or even another competitors truck and did some damage. 

 

[Nikko85]

It certainly can be. I'm not anti basher but I've certainly seen some videos of certain famous youtubers where very heavy vehicles are going head height wayyyyy closer to kids than should be. In areas designated for kids. 

An xmaxx in the face could well be fatal, or at least life changing.

[moffman]

18 minutes ago, Nikko85 said:

It certainly can be. I'm not anti basher but I've certainly seen some videos of certain famous youtubers where very heavy vehicles are going head height wayyyyy closer to kids than should be. In areas designated for kids. 

An xmaxx in the face could well be fatal, or at least life changing.

Totally agree! I have a maxx which I bought last year basically to get me into the brushless and lipo field and understand how everything works and I was having a blast over my local park always away from everything for a couple of reasons I’m left alone and because of the sheer power and speed it’s safer thus less hassle!! but what did shock me was every now and then other people were over the park with their rc’s and just basically being absolutely reckless without considering the environment they were being reckless in then after watching certain “YouTubers” the penny dropped on the language they were using one particular thing I kept on hearing “take it to the moon” very dangerous like you say you’re gonna notice when a brushless monster truck lands on you at 50mph……not good!

[Pablo68]

As a veteran of several of my RC cars doing burnouts on my table top or more often, my lap, I concur!
I hope you kid is ok.

It does well to remember that especially with modern lipo's and motors our cars can be putting out something not too short of the power of say a 4 and 1/2~5 inch agle grinder. That's my guess anyway, feels about the same in your hand.

[Mad Ax]

2 hours ago, Nikko85 said:

An xmaxx in the face could well be fatal, or at least life changing.

This is a concern of mine.  Recently on a local FB group someone asked about public liability insurance, as they were concerned about potential accidents, and they said they weren't sure that BRCA would cover them.  I must admit I thought BRCA covered bashing and was fairly comprehensive, but there again, you don't want to find it it's not valid after you've had an accident and someone has got hurt.

What worries me more is people buying stuff like this and acting without consideration.  Drones have already come under heavy legislation, which many in the RC flying world are very unhappy about because it affects them too, and there's signs up just about everywhere about not flying drones.  I don't want to see local parks and public spaces become "no RC zones" because of people using heavy large-scale cars without a care for other people.

In fairness, the majority of people are responsible - from time to time I see people playing with large electric and nitro bashers where I go walking, but it's a huge empty space on the edge of a military training ground (it's a mandatory empty zone between the training ground and residential areas), and if people, dogs or horses come through they stop and wait.  But use of motor vehicles on that land is not permitted (although some people do take dirt bikes there illegally), and I don't think we're that far away from the biggest and fastest of RC cars being just as dangerous as dirt bikes.  Perhaps more so, since one's own survival instincts tends to restrict what you'll do on a dirt bike, but that doesn't apply to an RC car - as you can see on YouTube from the "let's see how high I can get it" brigade.

[JimBear]

17 minutes ago, Mad Ax said:

What worries me more is people buying stuff like this and acting without consideration. 

This. In my mind are the minors; dad buys a large Arrma/Traxxas/etc and lets the young ones "have a go", and they go off to the skate park, having seen someone doing cool stuff on YT, and someone gets in the way ...

I know from experience how easy it is, since the boy wanted to do what Mr Johnny Barefoot (or whatever he is called this month) did. In this instance, both mum and dad were at hand, nobody else around and with the DT-01 he didn't get all that far, with the flying business. But still ...

We've only had one or two smaller incidents with feet/ankles getting in the way of the DT-01, but even the WLtoys buggy he had - much quicker; small but full of metal bits got me worrying about visits to the doctor. So, I've been trying to get the kid into crawlers instead.

[gogsyfinnie]

Really appreciate you sharing your experience Ax, being new to the hobby its very easy to overlook some simple safe habits.  I've been very careful with my (one) Lipo battery, which the kids are well versed about and tell anyone who come into our house how careful we have to be with it!  However things like working on the table without a stand and switching off transmitter / receiver in the correct order are practices I have definately been lax about.

Very glad your wee girl is ok and hopefully not too shaken up by the experience, my daughter is about the same age and loves getting involved in tinkering, so you've given me plenty food for thought to take more care.

[urban warrior]

2 hours ago, Mad Ax said:

What worries me more is people buying stuff like this and acting without consideration.  Drones have already come under heavy legislation, which many in the RC flying world are very unhappy about because it affects them too, and there's signs up just about everywhere about not flying drones.  I don't want to see local parks and public spaces become "no RC zones" because of people using heavy large-scale cars without a care for other people.

In fairness, the majority of people are responsible ...

It's always "the few" who act completely braindead, spoiling the fun for all the others. Drone regulations? Ask me, I live in Germany ... there will be a day where you get a citation when your car jumps too high in the air! The new regulations for flying drones are partly quite restrictive and so enigmatic that especially newbies will have a hard time to understand it. And all that because some "fraggles" found it funny to fly their drones at our airports.

[wolfdogstinkus]

Has anybody actually read my bible?.

I'm still accepting subscription applications from anyone who still has both kidneys and a goat.