Hobby Newbie Learning Diary; Family Included!

[mayan]

Went out flying today. Again a perfectly chosen winter day for flying, was nice and sunny with 0-5 km/hr of wind. Got my GoPro issue fixed, but had different problems in line for me... Hope you watch the video to find out.

@Arcfyre, @d8veh, @Hai-Lee, @rockyboy, @cranialrectosis, @donalson could you please have a look at the last few minutes of the video and give me feedback about what might be the problem? Or what to check to find out?

 

[PoorManRC]

Looks a lot like a Fried ESC....
But don't rule out that the Battery could have just been so low, that it was causing the ESC to cut power - which is what it's designed to do.
My 2 cents....

 

[mayan]

My guess is also the ESC

 

[d8veh]

@Arcfyre, @d8veh, @Hai-Lee, @rockyboy, @cranialrectosis, @donalson could you please have a look at the last few minutes of the video and give me feedback about what might be the problem? Or what to check to find out?

My guess is that there's something wrong with the ESC. they can get damaged when you crash or even if you have/had a bad motor connection. It's never a good idea to keep trying with a motor that isn't running properly because you can burn the motor and/or burn the ESC in that situation.

One other reason why a motor doesn't produce full power is the ESC not calibrated for the full throttle range. You have to look up how your works, but a common way is to connect the battery with the throttle fully open, then wait for some confirmation beep, after which you reduce the throttle to zero to store the throttle range. The ESC will then initialise for flight like normal..

 

[Arcfyre]

Seems to be either a low voltage situation like poormanrc said or a bad ESC.

Try cheating the battery first. Try it again at home and see if it works better. After that try the ESC off your Versa and see how that one performs. If it's still not spinning right, it's the motor.

 

[Hai-Lee]

Just as a different experience or opinion I will suggest that there is something else that can rob your motor of power, This is from experiences I had with a flying wing prototype I built a few years ago now. Simply put I had a fully working ESC motor setup that suddenly wouldn't rev out properly and produced very poor thrust. I persevered with the setup and one day I noticed that I could get it to work properly for a short period of time by wriggling the motor leads. I disassembled the motor and found that one of the windings was actually broken. I repaired the winding and the motor motor is still in use in another plane a few years later!.

Listening to the motor revving and dying at the end of your video sounds like a separate issue of high INTERNAL RESISTANCE of the battery pack.

When you open the throttle the battery voltage is quite high but as you try to draw serious current from the battery it "SAGS" and its voltage drops sharply causing the motor to slow down. The only real solution is a new battery unfortunately.

In relation to general matters there is something you should be aware of. When my students go from 2S to 3S or vice versa I make sure that the also change the prop to suit the new setup. High revs small prop low revs bigger prop. A prop that works perfectly at 3S will be actually underpropping the motor at 2S.

Just my opinions of course!

Have fun!

 

[buzzbomb]

MY opinion? I loved how tight you could turn that thing and then turn around go the other way. I've got one of those planes! I can't wait to do that.

For a more helpful opinion, I agree with the others: You've got electrical issues which are tough to track down. Heck, it could just be a solder joint that broke in a crash. Just from what I've seen in other videos, I'd check all the solder joints (inside and outside of the components) and the connectors. It does seem like you've burned the esc (which would be par for the course for your luck) but it seems like a loose connection would have the same effect. Maybe more so. A bad component is usually just that. They don't usually work now and not then, unless they heat up or something.

Also, at least with the toy-grade quads I have experience with, we had to bind the transmitter to receiver at each battery change.

Just mentally going through your video, it seemed like your range got shorter and shorter as the video went along. It was like you hand launched the plane, then it just lost contact. Receiver wire? Transmitter batteries or antenna?

It's just observation to help your troubleshooting.

Always, Mayan, keep in mind that I KNOW NOTHING. I'm just thinking things through with basic knowledge.

I really think you could fly through an entire battery if everything was working properly. Keep at it my friend!

 

[mayan]

Thanks for all the inputs. Well there is clearly a problem somewhere. I hope to find time today to find and fix the problem so maybe I’ll be able to go flying tomorrow before another rain storm hits us on Thursday.

@Hai-Lee same thing happened with a different battery. Could it still be connected to the battery?

 

[Hai-Lee]

Thanks for all the inputs. Well there is clearly a problem somewhere. I hope to find time today to find and fix the problem so maybe I’ll be able to go flying tomorrow before another rain storm hits us on Thursday.

@Hai-Lee same thing happened with a different battery. Could it still be connected to the battery?

It is possible that the problem exists in both batteries BUT you should also ascertain if the problem happens when the ESC is cold as in the early morning before you attempt to fly for the first time. Some ESCs have a temperature protection circuit that reduces the output to the motor if it gets too hot. Sadly I do have an example here where the plane flies perfectly for one battery and after that it doesn't even give enough power for a single take off. This condition can last for over an hour which effectively limits it to only one flight each morning. I must remember to buy a replacement someday!

On some ESCs the protection circuit can be programmed to completely cut the motor if too hot and some to just reduce the motor output, just check the ESC programming. IF it is overheating a few small holes drilled in the motor bulkhead could provide a little better cooling.

In summary. Check the motor and other wiring connections, Check to see if the problem still occurs when the batteries are fully charged, Get a larger prop for use with the 2S battery, Drill a few cooling holes in the motor bulkhead, Check the temperature of the ESC when the issue arises, and check the over temperature programming of the ESC. Finally buy a voltage checker/alarm to use in the plane or planes when they are flying, (I have a small number and mine are set for 3.4V/cell alarm under load). This setting leaves me enough power for about 30 seconds of motor power at full throttle so I can get to a place where I can land the plane safely. (Cost of the alarms is around $2 each from Aliexpress - if they deliver to where you live)!

An added benefit of the voltage alarms is that they monitor the battery cell voltages under load continuously and so if you have a battery that is sagging badly the alarm will sound under load and stop the alarm when you reduce the throttle. This normally means time to get a replacement battery or at least plan the purchase of one!

Hope this helps. The first bit of faultfinding always seems daunting but after a while you will find that the problems get easier to identify and remedy quickly!

Have fun!

 

[mayan]

Already have a voltage alarm on the way

 

[d8veh]

Bad starting and low power are consistent with a faulty mosfet in the ESC. Mosfets go faulty mainly when you overheat them or drive too much current through them. Too much current will flow if you give the motor too much throttle when stalled or or not able to turn fast enough, like when the propeller is too big. A faulty motor connection can make it stall or run too slow.

I'm not saying that a faulty mosfet is definitely the cause. My first step would be to try a different one.

 

[mayan]

Ok well I am going to need to make a few tests before I have more questions for you all. Hopefully I’ll be back later today with something....

 

[mayan]

Did so checking and this is my conclusion. There is a problem with the ESC that I was using. Checked it with this setup: MT1806 2280kv mottor > 15A ESC. I checked it with a 2S 1000mah, 3S 1000mah, and 3S 1300mah batteries all gave the same result. The motor didn’t start spinning untill the throttle stick was at about 80-90%. I tried letting it spin for a few moments but couldn’t seem to get the motor to die out like it did at the field.

I did the exact check (same motor) with a different 15A ESC and things seemed to work fine motor started spinning the moment I moved the throttle stick up. Did the check only with a 2S 1000mah battery because I was lazy to go get the connector and am afraid to ruin another ESC untill I figure out what caused the problem.

A few questions for you all.
1) The “damaged” ESC seems to be working but not working properly. I read here and there on the forum that you can program an ESC. Could the ESC have just lost its programming? How could I try to fix it?
2) The new 15A ESC seems to behave like it should. Could the 3S 1300mah battery have caused the “damaged” ESC to freak out?
3) What ESC would you recommend to use with this setup plan: prop (6x4) > motor (MT1806 2280kv) > ESC (?) > battery (2S 1000mah / 3S 1000mah /3S 1300mah)?

Looking forward for your feedbacks...

 

[Hai-Lee]

Simply put, Mark the ESC as suspect and put it aside! Fit a new ESC and go flying. Save your diagnosis for a time when flying is impossible and you have nothing to build or repair!

ESCs die for a myriad of different reasons and they are not really worth the effort to repair unless of course you are talking about a 200A type which has such a replacement cost that it can be more economical to repair rather than replace. Mind you if you have no access to parts then you would use it as a parts source against future failures.

As for the Dead ESCs I accumulate from time to time I use them as supplementary BECs if needed in some models where the Servo load exceeds the load limits of the existing BEC in the ESC. Great for an emergency 5V source!

have fun!

 

[mayan]

@Hai-Lee whats your thoughts about this:

2) The new 15A ESC seems to behave like it should. Could the 3S 1300mah battery have caused the “damaged” ESC to freak out?
3) What ESC would you recommend to use with this setup plan: prop (6x4) > motor (MT1806 2280kv) > ESC (?) > battery (2S 1000mah / 3S 1000mah /3S 1300mah)?

Another quick question: I think I saw on one of the FT videos that Josh Bixler said that you can completely kill a LiPo battery by putting it in salt water. Am I mistaken or is that how it’s done? Do you need a certain percentage of salt in the water?

 

[Hai-Lee]

For the prop I would use a 6x4 for 3S and a 7x4 for 2S. The ESC should be OK as long as it is the 15A and can handle 3S. The battery is best selected to give the required performance/thrust, (2S/3S), and is of the ideal weight to give you the correct balance. On my TTs I use 3S 850mA almost exclusively but many others use 1300mA so the choice is entirely up to you. Of course you will need at least a 20C capable battery with the correct connector of course.

The discharging of a lipo in salt water can be fraught with danger as the current you can draw is related to the salinity. a weak solution is best in my opinion BUT if I am required to discharge a battery to make it safe for disposal I like to use a 6V light bulb and connect it across a single cell in the balance plug. When the cell is 0V I then transfer the bulb to the next cell and so on until the pack is all discharged. I then check the voltage of each cell again and cut off the balance plug and twist the balance leads together to maintain the short permanently.

DO all such work away from anything combustible and with plenty of ventilation. Salt contains Chlorine and it is best not to risk breathing any generated due to a faulty battery or procedure!

Just my opinions as usual!

have fun!

 

[d8veh]

I don’t think a 15A ESC is enugh for that motor with a 3S motor. I haven't got my measurements with me, but I think I saw 25A using a 6x4 propeller and 18A with a 6X3. It'll be OK with 2S, but you should go down to 5x3 or similar for 3S or use a 30A ESC.

The damaged ESC could be caused by over-heating or when the plane crashed.

I don’t think programming will fix it.

 

[mayan]

Huarry I managed to go fly this morning. Kept it short today because I can very easily lose track of time and spend the entire morning at the field. Not a good idea when your wife asks you to do a few things while she is sleeping after her night shift. I went directly after dropping the kiddos off at school. Which is the best time to go flying any how because it’s not hot and the wind is light. Anyhow back at home right now, with half of the things my wife wanted me do done. A few more things I got to do and then I’ll sit down to edit today’s practice session video so you all can give me your feedbacks about my flying.

 

[mayan]

Check out today's flying session, I personally feel like I owned the sky . Felt in complete control of the plane at all times. Managed to bail out of 2 potential crashes and almost hand grabbed it when coming in for a landing . I am pleased with my learning curve. Can't wait for my orders to come in so I feel less stressed about breaking electronics.

Pure flying parts: 1:40 - 8:30 and 12:30 - 13:00

EDIT: I apologize for the times when you don't see the plane... If you have tips about how to get better footage, I'd love to hear them out.

 

[rockyboy]

Awesome job flying!

I do believe you've got it now