Author Topic: Smoked an ESC this morning! (Read 2212 times)

Andrew Borgogna · « **on:** August 13, 2010, 01:54:02 PM »

Well this mornings session was interesting. Larry and I made two flights, we each flew the pattern on the Sky Sport 350e. Before the second flight I changed the prop from an APC 9 x 4.5 EP to an APC 11 x 4.5 EP. The new prop seemed like a winner so the decision was made for the third flight to get off the R/C receiver and move to the timer. Well things didn't go so well on the first flight with the timer. The plane rolled a few feet and the wheels dug into some grass, it then nosed over and stalled the prop. Since we were on the timer we could not cut the motor and the ESC really burned big time. We were lucky the plane didn't catch fire, the wood behind the speed controller is charred, and so is the controller.

So this begs the question should I have a fuse on my battery connection, and if so what percentage of the total current capability of the controller should I make the fuse. Example, the ESC I was using was a CC 36amp controller, should I fuse the battery connection at 30amps? Or should I just stay off grass.

Andy

John Hammonds · « **Reply #1 on:** August 13, 2010, 02:57:15 PM »

Despite what others will probably say I don't think a fuse will do you any good.

I used to race 1/10 R/C off road buggies and we used to use a 35amp fuse, I never had one blow and it took a lot more that 35 amps to haul a 4WD off road buggy off the line. I think it was more of a "Comfort Blanket" than anything else.

Fuses just don't react quickly enough. I think you would be better served buying an ESC which recognises a prop strike, I've had aircraft nose over once or twice and my CC phoenix have always detected this and shut down.

To be honest I think a fuse is just extra weight... but YMMV A lightweight circuit breaker on the other hand........

TTFN
John.
.

Larry Renger · « **Reply #2 on:** August 13, 2010, 03:20:13 PM »

Here are a couple of photos: before and after.....

And, I'll bite, what is YMMV?

Tim Wescott · « **Reply #3 on:** August 13, 2010, 04:39:33 PM »

Quote from: Larry Renger on August 13, 2010, 03:20:13 PM

Here are a couple of photos: before and after..... And, I'll bite, what is YMMV?

Toasty!

Your Mileage May Vary.

Rudy Taube · « **Reply #4 on:** August 13, 2010, 05:09:12 PM »

Hi Andy,

I agree with John. A fuse may not be the ans., for several reasons.

Please, Please use a CC ESC (or other quality full feature ESC). Your ECL life will be so much happier!

Like John said, his CC ESC will shut down automatically for you. They have a safety circuit already built in. It is the default setting in the setup section, already done for you. :-)

Nose overs:

This does bring up a good point about a slight change needed in an ECL plane that is flown on grass. 90% of all my flying is off grass. In the beginning I had a few nose overs, and yes the ESC does eventually shut down, but it is still not good for our systems. If flown off grass, and/or rough field, we just need to address this issue with:

1. Taller gear for better clearance for our typically larger props.
2. Make sure our gear is angled forward, placing the wheels forward of the LE of the wing.
3. Replace the "soft" metal LG that comes on many CL planes with stronger American metal of the same or slightly thicker dimension.

The above requires making a new gear or a redesign of the attachment area but it is easy to do (even I can do it! ;-).

Regards,

Igor Burger · « **Reply #5 on:** August 13, 2010, 05:10:54 PM »

Andy, it will sound silly, but we found that the best fuse is prop nut wich is not tightened (too much)

John Cralley · « **Reply #6 on:** August 13, 2010, 05:29:52 PM »

Larry,

Contact Castle Creations and see if they will replace the ESC. I think (can't swear) that the Thunderbird ESC is supposed to have a thermal or an over AMP shut down function. Disclaimer: I have a Thunderbird ESC but I have never used it and all of my CC experience is with their Phoenix series.

My Phoenix ESCs have simply shut off in similar situations.

John

Andrew Borgogna · « **Reply #7 on:** August 13, 2010, 06:49:16 PM »

I will check with Castle Creations to find out if the Thunderbird model has a prop stall detection circuit. If it does then this one clearly failed. Then again stall detection maybe something found on their more expensive units. I like Igor's suggestion I just wish he had a torque value to go with it. The idea of a prop flying off in the overhead eight is a little scary. Oh well everybody seems to agree that a fuse is a waste of time.

Thanks everybody, I got a replacement ESC today. But it's the same unit that burned. Wish I knew about this prop stall circuit before I purchased the replacement ESC.

Andy

jim gilmore · « **Reply #8 on:** August 13, 2010, 07:37:35 PM »

This brings up a question.
If a fuse is too slow to prevent a esc from buring under too many amps.
What would react fat enough?
is there a simple device ?

Rudy Taube · « **Reply #9 on:** August 13, 2010, 10:05:22 PM »

Quote from: Andrew Borgogna on August 13, 2010, 06:49:16 PM

I will check with Castle Creations to find out if the Thunderbird model has a prop stall detection circuit. If it does then this one clearly failed. Then again stall detection maybe something found on their more expensive units. I like Igor's suggestion I just wish he had a torque value to go with it. The idea of a prop flying off in the overhead eight is a little scary. Oh well everybody seems to agree that a fuse is a waste of time.

Thanks everybody, I got a replacement ESC today. But it's the same unit that burned. Wish I knew about this prop stall circuit before I purchased the replacement ESC.

Andy

Hi Andy,

NOTE FOR EVERYONE: PLEASE DO "NOT" USE ESCs (IN CL) THAT DO NOT HAVE THE HIGH CURRENT CUT OFF FEATURE!

The Thunderbird line of CC ESCs was designed to compete with the less expensive competitor ESCs that have very few features but are easy to setup, more plug and play ease for RC park flyers etc. It does NOT have the "Current Limit" feature that we really should have in ECL. I'm sorry, we should have gotten this info. out to everyone a long time ago. I will try to get the word out on this important safety feature.

All the CC ESCs above the Thunderbird line (and the other quality ESCs) have this important feature. This feature is adjustable, but for our needs I think it is best that we stay with the default factory setting that is called "Normal" sensitivity. The other settings would just cause us problems and are mainly for non ECL uses. The default setting works OK for us. The "Sensitive" setting just below the Normal setting would be a little better for us in a nose over, but you would run the risk of the ESC cutting out with a sharp current spike, say at the top of the second turn in the hourglass in the wind just when this would be "less than fun"!

If you bought it from a LHS I am sure they would exchange it for you. The Phoenix line is very good, and light, and should easily meet your needs safely.

CC Phoenix Info. Link: http://www.castlecreations.com/support/documents/Phoenix_User_Guide.pdf

Jim,

RE: Your question ".... What would react fast enough? ..." Answer: CC Phoenix ESC or above, or other quality ESC with the Current Limiting/shutoff feature.

WHAT YOU WILL SEE/HEAR

With the factory default setting on the Current Limiting feature on your Phoenix (or above) ESC, this is what will happen if you have a nose over, or a mishap/crash that stops the prop: (please don't ask how I know this ;-)

1. The ESC will scream it's little head off with the 3 beeps repeating telling you that there is a serious current overload, and the lights will be flashing. You have a few seconds to get to the system/plane and:

1. PUSH THE OFF BUTTON, or
2. PULL OUT YOUR SAFETY PLUG, or
3. TURN OFF YOUR ESC SW IF YOU USE ONE, or
4. UNPLUG YOUR BATTERY or
5. Wait a few more seconds and let the ESC shut everything down.

If possible, I recommend trying 1 to 4 if you can get to the plane. If your ESC is buried inside a balsa fuselage and there is local noise (like a loud wet CL plane nearby ;-) you may not hear the alarms or see the flashing lights. Just assume they are there and act accordingly.

I always give my helpers at a contest a short talk about this possible event. I remind them that they need to grab the plane firmly and expect the prop to come up to full speed immediately after they tilt the fuselage back up to normal. Then do one or more of the above 1 - 4 steps. I show them where all these features are located.
IMHO: Until ECL becomes more common I think it is very important for all of us to train as many holders as we can in these issues.

Regards,

Mark Scarborough · « **Reply #10 on:** August 14, 2010, 12:17:08 AM »

Rudy!
Good to see you again,,
well written post, especially the second part. The thing that came home to me was to INFORM your helper/assistant of what will happen. Never thought of that but A recent expirience I had bears witness to the need to rethink some of our "normal" responses.
FWIW, a friend of mine, whom is learning to fly CL, is very familiar with electrics, but in the RC world. He was flying his E-trainer. On one flight His combination of prop and flight time caused the battery voltage to drop off, and the ESC went into voltage cutoff. All as intended UNTIL, the plane lost airspeed and glided in for a nice landing. I was about to congratulate him on not panicking and making a good landing on the grass. ( normally anything would tip over on this grass, its a touch longer than perfect) However, about that time, his son went over to retrieve the Model across the circle, about the time he was 10 feet away from picking it up, The ESC reactivated, the timer still had time on it so the plane just decided to fly some-more. Now in THIS situation, it all was more funny than dangerous, Of course we got lucky and this was a small plane anyway, not some .60 "sized" full blown stunter, but still , you get the point. Much to my friends newly reinforced habit to never lay the handle down until someone has the plane in hand, no real harm came of it, Just Another thing to keep in mind,,,,,

But still, the sight of that plane chasing his son as it tried to come back up to speed,, well it was priceless.

Dennis Adamisin · « **Reply #11 on:** August 14, 2010, 05:52:40 AM »

Rudy makes lots of good suggestions. I don't want to say the "S" word, but we need some universal guidelines like:
* using a arming plug on any bird with the components located internally
* Said plug should be located well away from the prop, preferably can be operated with one hand
* Hubin timers will shut-off using the starting switch in the first 1 minute after pushing the start in the first place. (do other brands do the same?)
* Make sure our helpers understand the above.
* When I look over someone else's electric bird I find myself looking for things like the arming plug, "just in case"

In my first installations I used the bullet connector as a arming plug. Works nice but I hate the blue spark when I hook-up. I recently started using the Maxx products arming plug with is basically an Anderson Power Pole. Nice system but too big and clunky. Got anothe project on the board that will use a blade type fuse as the arming plug. In short I think we need some gray matter on this topic and come up with a better way.

Lots of us ar using over-sized props on our electrics, OK if the bird has the LG legs for it, not so good otherwise. In ANdy;s example here he lost a full 1 inch of prop clearance with his new prop - that is a lot to give up.

I like Igor's suggestion about the slightly loose prop hub but would not trust myself to know just how to set it.

BTW CONGRATS to Andy & Larry, they are now the first ones to report FLIGHTS with the new 11x4.5!

Andrew Borgogna · « **Reply #12 on:** August 14, 2010, 10:59:17 AM »

Rudy, Dennis, and everybody else who responded
Thank you for the information. Rudy as the saying goes "Timing is everything". If I had read your valuable information BEFORE I had soldered on the connections to the replacement Thunderbird ESC I certainly would have be able to return. I have offered a part time job at the local hobby shop I go to and know the manager very well. But it's too late for that. I guess I can use it for park flier R/C, I would not want to use it in C/L application with a timer. To add insult to injury the motor is toast as well. I took a good look at the polls and can see damage on one of the polls.

Regarding the 11 x 4.5 APC EP prop I liked the way it worked with the Rim Fire .10. Both Larry and I saw improvement in the overhead eight near the end of the flight. With the 9 x 4.5 I had to fly it off center because of poor line tension, but Larry using the 11 x 4.5 EP was able to fly overhead with good line tension. The only change was the battery and prop.

Anyway I will be getting a new motor and ESC, but I think I will wait until after I start work at the hobby shop. I want to see if I get the employee discount.

CircuitFlyer · « **Reply #13 on:** August 14, 2010, 09:01:58 PM »

Andy,

I was able to rewind my Rimfire 300 after a similar accident. Electrifly uses a exceptionally good glue to mount the stator but I was able to soften it by soaking the stator/frame assembly in lacquer thinner for a week (remove the bearings first). I then used long socket head cap screws in the frames threaded holes as jacking bolts to push the stator off the frame. Give it a try, then you will have a free spare motor.

Mark,

What brand of ESC was that? Sounds very dangerous. I would have thought that if an ESC cuts out due to low voltage it would stay off. Maybe its a brand of ESC that should not be used for ECL.

Everyone,

Is it not possible to use insulted control lines and mount the timer on the control handle? It doesn't even have to be the timer just a ESC switch/emergency OFF switch.

Paul

Rob Smith · « **Reply #14 on:** August 15, 2010, 09:05:04 AM »

Paul the ESC Mark is referring to is a Castle Phoenix 35. The timer was an E-flite unit. The problem arose due to the battery voltage dropping off and the controller shut down. The model was landed but time remained on the timer. After the battery sat for a second the voltage must of rose slightly, enough to allow the timer to restart. Unfortunately the E-flite unit only allows the user to set the cut off time in one-minute segments. We were trying to get in a bunch of short trim flights and pushed the envelope a little far.

I'm currently powering my E-trainer with the Hyperion VX cells. They are awesome! I've used many of the current batteries on the market and the VX cells are extremely durable and able to be charged at greater than 2C rate. I'm a beginning CL pilot so my batteries have seen many crashes! All packs holding up very well. I've since purchased a couple of timers for Wil H. an put the E-flite timer to rest. I now prefer to use the "set RPM" mode in the controller software. Also, I've gotten a pretty good fix on exactly how much time I can safely squeeze out of these packs. The funny yet very dangerous event won't be happening again anytime soon.

In regards to the first question of this thread - All my castle controllers have shut down after a propeller strike or a crash. In my many years of using Castle controllers I have fried a couple in R/C models but that was simply due to pushing them hard with inadequate cooling airflow. I have had one defective one as well. Personally, I would spend a few extra dollars and move up to the Phoenix line of Castle Controllers. The flexibility is well worth the extra money spent.

Rob

CircuitFlyer · « **Reply #15 on:** August 15, 2010, 03:20:30 PM »

I'm using an e-Flight Pro ESC. It has what they call soft low voltage cutoff. When the voltage drops the motor cuts intermittently or oscillates so you know its a low battery.

Andrew Borgogna · « **Reply #16 on:** August 15, 2010, 04:30:04 PM »

Hey Rudy
Do you know if the Hacker ESC that Eric is selling in his turn key configuration has the current limiting circuit in it?
Andy

Rudy Taube · « **Reply #17 on:** August 15, 2010, 06:29:30 PM »

Hi Andy,

Yes, it has the "current limiting" feature. It is a quality full feature ESC. The Hacker Pro that Eric sells is very similar to the excellent Jeti ESCs.

Will Hubin · « **Reply #18 on:** August 15, 2010, 07:11:25 PM »

I have an E-Flite combo PT-19 R/C_C/L plane with an E-Flite motor and ESC. A friend was flying it off of grass and it nosed down. Without thinking very clearly, I didn't check it for overheating and let it re-start; this time it nosed over and (literally) smoked the motor.

Incidentally, all of my timers will shut down with the start button throughout the flight time (not just the first minute), so telling an assistant to push the start button after an upset would be good advice.

Will

Rudy Taube · « **Reply #19 on:** August 15, 2010, 08:16:42 PM »

Quote from: Silver Dart on August 15, 2010, 03:20:30 PM

I'm using an e-Flight Pro ESC. It has what they call soft low voltage cutoff. When the voltage drops the motor cuts intermittently or oscillates so you know its a low battery.

Hi Paul,

This Volt lower limit is a nice feature, and like you suggested the correct setting for ECL is the "soft" V cutoff option.

Just to be clear; the prop strike and early cut off problem that Andy and others are talking about has to do with the "Current Limiting" feature that full feature ESCs have. If there is anything that causes the current draw to elevate above normal (or the setting you choose), the ESC will shut down everything to protect itself, the motor, and the battery from damage. The common causes are:

1. Too high of a load (demand) on the system due to too large a prop, too high of RPM, too long of time selected, ESC too small etc. Pilot selected setup is incorrect.
2. Over heat. Ex: Las Vegas in Aug. without adequate cooling to system. (over heat on ESC, not pilot! ;-)
3. Prop strike on TO, or crash.
4. Anything else that over stresses the system.

We should select the factory default setting of "Normal" for most of our ECL flying. ...... The exception to this is if you are doing BASIC training with very new CL pilots, like kids etc. Here I would set this feature to the "sensitive" setting. This will be a much faster cutoff in a prop strike or any other problem situation.

These are two different safety issues. The V lower limit cut off is just there to protect the battery from running below its safe V minimum and doing damage to the battery only. Fortunately almost all ESCs have this helpful feature. :-)

Howard Rush · « **Reply #20 on:** August 15, 2010, 11:46:08 PM »

Quote from: Rudy Taube on August 13, 2010, 05:09:12 PM

3. Replace the "soft" metal LG that comes on many CL planes with stronger American metal of the same or slightly thicker dimension.

As a person who worked for a company enamored of outsourcing, I think you will find that the problem is not the nationality of the metal, but that the guy who specified and accepted the alloy used in the product is incompetent.

Warren Leadbeatter · « **Reply #21 on:** August 16, 2010, 01:21:53 AM »

Quote from: Will Hubin on August 15, 2010, 07:11:25 PM

Incidentally, all of my timers will shut down with the start button throughout the flight time (not just the first minute), so telling an assistant to push the start button after an upset would be good advice.

That is good advice Will!

Rudy Taube · « **Reply #22 on:** August 16, 2010, 03:27:21 AM »

Quote from: Howard Rush on August 15, 2010, 11:46:08 PM

As a person who worked for a company enamored of outsourcing, I think you will find that the problem is not the nationality of the metal, but that the guy who specified and accepted the alloy used in the product is incompetent.

Thanks Howard, your correct about the "nationality of the metal not being the problem".

I should not have used any nationality in the way that I worded my post. Specs and acceptance do matter. I should have been more clear and said what I meant: "Buy your LG wire from a supplier that you know can supply you with wire that will meet your planes LG needs. That supplier may be your local hobby shop where you can touch, feel and bend the wire yourself and maybe even get some specs on it. Or you can order it from any supplier anywhere in the world that can supply you with the correct wire for your mission."

Myself, I just went to my LHS and bought some KS 3/32 wire that from past experience worked on other similar weight planes. :-) I have also addressed this LG problem by ordering the excellent CF gear from Randy. A source we can all trust! :-)

But your point is well taken. The ARC/ARF business has been accepting this soft LG wire for decades, long before CL ARC/ARFs. It is an on going problem that has been very difficult to solve. I remember promises and smiles and bows, etc. , but still the same stuff, no matter how many times we pointed to the specs. I remember that it was more a case of choosing our battles wisely, we often had other more pressing problems at hand. ;-)

The CF LG that comes on our RC ARFs are now excellent. It only took us about 5 years to get them right. I think our CL planes are still at the bottom of the priority list at the mfg., and it will take more time to get these minor problems sorted out.

With your talent and experience I wish you would step in and help our cause. I'm sure Randy, Brad, John and Steve would be thrilled to have you help them help us. And we all would be greatly in your debt. I would love to have someone help us jump ahead several years in CL ARC/ARF mfg. evolution! That would be great. If I could have a CL ARF that was even close to the excellent high quality standards of my RC ARFs I would be a very happy camper. .... Please help us out Howard, we need you! :-)

Regards,
Rudy