Sprint Cat 40/80 failures..?

[kevinpratt823]

I could use some input from the experienced guys, especially with this hull. Now I am by no means an expert in FE boats, but I came a long way relatively quickly, with a good background in electrical theory and RC cars, but it was a smokey and expensive learning curve getting into boats and chasing speed. Unfortunately, I have run with one other person twice, aside from that the most experienced guy I have to run with is a questionable character(myself), but I have actually leveled off a bit and succumbed to setups that will run without burning....

So I built this boat http://forums.offshoreelectrics.com/...at-40-80-build

I ran it a couple times, and was a bit dissapointed that I only got 50-55mph at best, with a X452 and X455 slightly detoungued. Third time I had it out for testing, on the second run the Neu 1527/1Y had a wire come unsoldered, I was kind of surprised that a motor of this size/caliber only comes with 13AWG on it, but that's another story. The ESC also failed, and I wasn't sure which caused what. First run was 3 min, came back in with motor at 160, ESC I think 150, and I thought this was a bit high. Let it cool a few min, motor was down below 100 deg when taping back up, ran it again, and it let go 1-1/2 min into the run. Data logging showed a max of 191 amps. I really thought these components really shouldn't even be breaking a sweat, and I was a bit puzzled with the failure.
I brought it home, and ordered a TP 4060/1400kv to hold me over until the Neu came back from repair. Threw it in, with a SF240 I had on the shelf, and ran it today with a X450, cooled it down for a good 15 min, then a X452, again it made it about 1-1/2 minutes before it quit, and now the esc just cogged the motor then let out a whisp of smoke on the shelf.
Both props were just a quick sharpen balance detongue jobs for the trial runs, 455 had a bit of back cut too.
I have considered the obvious stuff, and don't see a problem, so I just wanted to invite some outsiders in to my brainstorming process here.

The boat ran with the WA-WA's a bit, the nose bobbing up and down, so I gave it a bit of negative angle(helped a bit), I obviously had some time to spend getting it tuned to run right, but I really didn't think I was pushing the electronics. Could the WA-WA be straining it that bad, but the data logging isn't picking up the spikes?
Strut was between 1/8"-1/4" for all runs.
Timing was 12-14 deg
Cooling lines were 3 mm inside, from a dual pickup rudder, and water was streaming out a foot from the outlets on every run at med speed, could I need larger lines?
Drive dog had about 3/16-1/4" gap, and was greased and freely moving, but being a 3/16 flex with larger props, combined with the WA-WA could it be shortening to the point of bind as it comes in and out of the water?
Packs were (4) 3s Dinogy or Thunder Power 65C
Max RPM was just under 25k
Did a quick fill/sand on the ride pads, but they still had a slight slope up to the outsides.
Motor bullets were rather hot the first runs, but the motor/ESC temps didn't seem off the charts, but they obviously got there, as the logging showed an increase to almost 200deg F at the end of the first failure, I kind of chalked it up to the motor letting go and taking the esc with it at the time. Again, I really wasn't expecting this to be a real aggressive setup, was I wrong? I believe some of you guys are making 4+ minutes with these component without issue. Should it be that critical that I let it get all the way down to ambient temp before getting back out?
Mind you, I have been running my other 3 boats on the same days, in the same manner, with no issues. Outside temp is 60-70 deg, water is still pretty cool. My other boats(whip20, Cyberstorm, and Sniper 45") are on the aggressive end of reliable, running 55-68mph, and motors are barely getting over 110 deg right now.

Thank you if you took the time to read this, I'm just a bit baffled right now, I wasn't expecting these issues, and I can't really chalk it up to a series of coincidences, though I am considering getting a SF300, as I think I need some more weight up front anyway, but I really thought the 240 should run this motor fine, like I said, logging only showed 191 amps, and the first one had a monster ETTI cap bank on it.....I can see that some of my initial settings obviously wouldn't be ideal at first and would need some fine tuning, but I would think I would have some headroom for error........
Here is some quick vids of the first runs on a slightly choppy day, before the first failure....
X452-https://www.youtube.com/watch?v=09SpeEncUUc

455 with an odd blowover-https://www.youtube.com/watch?v=jblctP4xvkE

[Fluid]

I have been running a 'similar' setup for years. Several things could be wrong with your setup. First, my strut is about 3/4" above the sponsons, I have run it higher with the x455. Back cutting the prop reduced the thrust quite a bit - not needed with a cat hull. The WA-WA causes high amp spikes and stresses the ESC, and reduces speed too. Strut height and CG are often the cause as is a not-so-flat ride pad.

Where is the CG? Truing the ride pads will make a difference. Getting the boat to run smoothly will help with both heat and performance. Four minutes is too long with the big prop IME, that's a sprint setup and heat will build up. The TP is not a Neu, and no one in my club has had much luck with the SF controllers. I run 15 degrees advance. Too many differences between my setup and yours to know for certain but these are some ideas. You should be having better luck than you are, regardless.

[kevinpratt823]

I have been running a 'similar' setup for years. Several things could be wrong with your setup. First, my strut is about 3/4" above the sponsons, I have run it higher with the x455. Back cutting the prop reduced the thrust quite a bit - not needed with a cat hull. The WA-WA causes high amp spikes and stresses the ESC, and reduces speed too. Strut height and CG are often the cause as is a not-so-flat ride pad.

Where is the CG? Truing the ride pads will make a difference. Getting the boat to run smoothly will help with both heat and performance. Four minutes is too long with the big prop IME, that's a sprint setup and heat will build up. The TP is not a Neu, and no one in my club has had much luck with the SF controllers. I run 15 degrees advance. Too many differences between my setup and yours to know for certain but these are some ideas. You should be having better luck than you are, regardless.

Thank you for taking the time. I didn't realize the strut should be up so far. CoG is at around 11-1/4"(per some input I got from you in a previous thread), maybe a touch forward when I shifted the packs a bit. My total run times so far have not been over 3 min, with just over 3000 mah back into the 5000 3s packs, I was trying to keep it conservative for the initial runs. I know the TP is sub-par compared to the Neu, but it put me back on the water after the Neu failed in the previous run. Any advice on a controller that might suit my abuse better. I am not as familiar with the higher end stuff, and it appears Shulze is tough to come by now.....I know the first ESC had been previously repaired at Hifei, the second one has been around for a while, don't remember if it's been repaired but I don't think so....
Thanks for the input, I'll get back to the drawing board and try the higher strut hieght and such, just need to get an appropriate ESC in the meantime, and hopefully have a quick turnaround on the Neu....

[Fluid]

I have had decent luck with one TP motor as had one club member. Cogging due to a bad motor or a bad connection is very hard on the ESC, this could have been what took out the SF. Schulze controllers are out of production and pricey anyway. Frankly I still use Castle controllers, the aircraft variety. With a fan mounted on top they work well in hulls with a lot of air volume like cats. Water cooling is better but the fan is a simple mod. The T180s are pretty good, club members have had good luck with them as long as they are not abused.


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[NativePaul]

I was going to say that there is something very wrong as I get around the same speed as that and my 1521 does not get very hot at all, and nor do my connectors which are a mix of 6mm and 4mm, mine is on 8s, 1521/2.5d 1200kv, detongued X440, 5.5 minutes runtime on 6600Mah which is an average of about 70A (I don't know what my spikes are, in this boat I run a $45 Suppo 200 GS BEC ESC which does not have datalogging, but 50-100% more than average seems par for the course from my other boats with Castles), I was thinking that you must have been pulling 190A with peaks on top of that like you were wondering to kill a 1527 and not getting the expected speed for the power.

In your last post however you say you got not over 3 minuets run from just over 3000mAh, which sounds like not much over 60A average if it was close to 3 minutes and 50-55MPH is pretty darned good for that power (I'm assuming 6s), with an untuned boat that has a case of the wah wahs I could see a 60A average getting the odd 190A spike, but I cant see that taking out either of the motors.

Can you post the graphs? They would help show whether it us unexpectedly slow for the power, or running pretty efficiently at low power and somehow killing stuff.

I have run my prop from level with the sponson bottoms to where it is now about 8mm up, and it did run better as I went up but any higher than I am I got some unwelcome prop walk, but no signs of anything overheating. Not that mine is directly comparable with your and Jay's setups as it should be a fair bit lighter with its 8s1p and smaller motor and if my little 40mm prop was 3/4" above the sponsons it would barely touch the water.

[kevinpratt823]

Jay, I'm pretty sure the motor cogging was due to some blown Fets, it only did this after the second failure when I bench tested it, upon which the esc let out a whisp of smoke. I think the motor is fine. Both motors were brand new BTW, 8mm bullets w/silver solder, 8mm bullets on the batt leads, with paralell adapters down to 5.5mm bullets for the packs. I really can't picture a T180 with this size motor.......

Paul, the boat runs 6s2p/10,000 mah, it was just over 3,000 back into each of the (4) 3s/5,000 packs, so I really ran prob 6,500-7,000 mah in 3 min. I'll try to post a pic of the graph...

[kevinpratt823]

This was the first runs, I believe it may have been the first failure with the neu....On closer inspection, I'm sure it didn't help that the ecs started the run still pretty hot from the one before, I really thought it would've cooled down more in between. I'm leaning now towards the strut depth bringing the heat up, and not enough cool down in between runs, but today's failure had quite a bit of cool down, I ran a set of packs in 2 other boats while it sat, including temp checks and pack swaps in those after each run. No data logging in that esc unfortunately though.

Sent from my SCH-I535 using Tapatalk 2

[Fluid]

I run the 1527/1Y in my Q Sport boat and average 140 amps, a T180 would work fine although I use a Castle 200LV controller. Two club members have run the T180 with the same motor in their boats. I'm not really recommending it but it is an alternative. Too many people think that the higher the voltage they run the higher amp rating on the ESC needs to be. Not true, use voltage for more power not more amps.

Try raising the strut until the prop blows out, then lower it a bit. Try moving the CG back a half inch. Angling the prop end of the strut a degree or two might help too. It will take some tuning but you should get there.



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[kevinpratt823]

Update, the second failure appears to be only the motor, visible cooked winding on the shaft end. Perhaps a freak coincidence of a bad motor, perhaps not, it was a brand new TP motor but id did seem pretty slow the couple minutes I ran it. I just tested the esc in another setup and it appears to be running fine.

[madmikepags]

I'm with Jay here. I've run this setup for almost 6 years, with a 452 prop with a lot of pitch. I easily get 4 minutes of runtime at over 60mph and have almost 30% left in the batteries. He said he used 3000 mah in 3 minutes but he has a parallel setup which mean he used 6000! My strut with 452 prop is 3/8 to 1/2" above the sponsons and the CG is about 35% (12.5") from the rear and I always run my strut level adjust ride attitude with cog. There has to be something wrong like a kink in the shaft, the teflon in the tube binding, a bad bearing? shaft biding? something going on????

[kevinpratt823]

I'm with Jay here. I've run this setup for almost 6 years, with a 452 prop with a lot of pitch. I easily get 4 minutes of runtime at over 60mph and have almost 30% left in the batteries. He said he used 3000 mah in 3 minutes but he has a parallel setup which mean he used 6000! My strut with 452 prop is 3/8 to 1/2" above the sponsons and the CG is about 35% (12.5") from the rear and I always run my strut level adjust ride attitude with cog. There has to be something wrong like a kink in the shaft, the teflon in the tube binding, a bad bearing? shaft biding? something going on????

No teflon, brand new shaft, greased and inspected between outings, thrust bearing spins freely, but I may remove it. Shaft spins freely when collet is loose, with at least a 3/16 gap. Like I said, data logging MAXED at 191 amps, that's maybe a tad high, but not by far. If something was binding I would think I would see higher currents, no? The only thing possibly out of the ordinary was some temp buildup. I have replaced my cooling lines with larger ones, I will get rid of the thrust bearing, and raise my strut considerably, with the 452, beyond that I don't know. There were some slight markings on the shaft where the thrust bearing was, but nothing that concerned me, the shaft was still smooth there.......As far as the power consumption, I don't know, but if you watch the videos, it's not going that fast, even at full throttle(likely due to prop/strut settings). The videos were from the first day running, the day it let go, I'm sure I was on it a bit more, staying wide open through more turns, in a tighter oval, again with an inefficient prop strut setting, so that may account for the consumption.
Again, thank you guys for the input, and following through with me here, I'll get her where she needs to be eventually and it will all be worth it I'm sure.
On a side note, not that this is causing my issue, but are you guys blueprinting your ride pads so they are perfectly flat across a board? They seem to be molded with a slight angle up and out at the edges, wasn't sure if it was designed that was for a reason.........

[iridebikes247]

max temperature of 101? Thats crazy, I put 14,500 watts through the sf300 and never see over 70 degrees celsius on data logging....not the same esc but same software/ideas behind it all.

any chance water cooling was for some reason just not working at all at speed? thats my only guess. If it was something purely electrical it woulda blown earlier in the run.

[kevinpratt823]

max temperature of 101? Thats crazy, I put 14,500 watts through the sf300 and never see over 70 degrees celsius on data logging....not the same esc but same software/ideas behind it all.

any chance water cooling was for some reason just not working at all at speed? thats my only guess. If it was something purely electrical it woulda blown earlier in the run.

I haven't put much more than 8500 watts through the SF300, but it does seem to be a very different animal, it barely gets warm for me. But nonetheless, would you still agree that 101 deg C is pretty high, even though I started the run at 62 deg C? I was very attentive to the cooling outlets, and from the best I could tell, they were working, but there's always a chance as it's hard to see at speed, hence my upsizing of the lines. I will certainly be paying a lot of attention to it next time out. But still, the boat should have been faster IMO, which leads me to think there was a lot of power being wasted, and so far the only place I can see that is with the inefficient setup.....

[iridebikes247]

Yeah I agree that's really hot. Could have been an esc issue? the tp 4060 and the 1527 are pretty well made motors to get them that freaking hot something was clearly wrong. If it was running really wet things would warm up but not to the point where you're blowing stuff up that quickly.

I always blow through the lines before running the boat, well most of the time at least. Data logging looks normal...Kevin you have a seaking 180 right? maybe try it on lower voltage with the tp motor, see if temps go down after checking cooling? could have been a defective swordfish esc causing your problems.

[madmikepags]

baffling???? it seems like everything is right??? I had a boat once that wouldnt run right, Big 10S cat, 30-40 seconds each time, burnt motor, next time burnt controller (twice actually), next time shaft and stuffing tube, rebuilt it new drive line new motor new controller. It finally ran great, for 2-1/2 full minutes. I stopped to catch my breath (it was a 75mph boat) and the boat just took off by itself hit the shore and the boat was destroyed. I don't believe i ghosts but I've seen plenty of gremlins screw up rc stuff????

As I'm typing this I realized that swordfish controllers don't always calibrate correctly, you sometimes have to calibrate it at 100% throttle then turn the throttle epa to 120%, This could be why you're not getting top speed and why the controller is overheating??? I had this problem with a SF300 in a big rigger.