Extra help to hydro over heating issues.

[Ryanj]

I have some data here on my sons 1/7 scale hydo, Ml boat works hull built a few months a go. We tested the boat twice testing temps 130f and Saturday was the 1st day for racing in a local club. The boat ran really hot and burnt up that motor in first heat. I reset the strut up more to center line of the sponson like normal and he got a a 2nd motor from a member in the club to run again and the boat ended up burning that motor up as well. He was not happy. he ordered a new motor on Saturday evening and I've been all over the boat as the set up, to check water flow, running too wet and anything i can think of. Found One cooling line was tight as to what i can find and maybe causing a pinch with the cooling line at the rudder. Replacing all the cooling lines this week.
I have also been over the data on this XLX2 esc and to what i know for the past 2 days. As to Help for extra insight to additional information to the data to help narrow some issues down to avoid burning up another motor.

The Ripple is low to what i can tell that stands out. The only thing that comes to mind at least with the data, the Voltage Sag/drop at times up to 5 volts when at full acceleration. To what i do understand to a point this can affect the Amps of the system, Low volts, high amps to watts. my only thought to whats going on.
I was going to add a Castle Cap pack to The Esc to help stabilize the power flow and see what the does and data/temps as i dont see a Cap Pack on the esc , Next step was bigger MAH lipos and higher Rating. Other then that to what I'm seeing, if there any more ideas to this issue will be great thanks.

Boat information, Motor size and prop are Spec for racing class. Have to run Those for racing.
Ml boat works 1/7th Scale Newton 158/ MHR 8200, 8401, 8700 - hull
Esc Castle XLX2
Batteries, 2x CHNL 4s 90c 6200 Ran in series for 8s
Motor, 4092 850kv 8mm shaft 3000-5000 watts
1/4 flex cable
prop 5714
data log 1.7 scale.jpgimage1 (2).jpeg

[ray schrauwen]

IMO a 4092 is too small for that hull. Others need to chime in...

I would use a motor in the 56mm diam. range.

[Ryanj]

IMO a 4092 is too small for that hull. Others need to chime in...

I would use a motor in the 56mm diam. range.

Yes I would agree a bigger motor. Unfortunately rules to this spec class racing in my club states 4092 850kv is the motor to run and a CNC 5714 prop as well. Gotta work within the rules to size. There are a few other boats with the same motor and prop so assuming it’s gotta be the set up I may have over looked. Thanks for the response

[RaceMechaniX]

The ripple is not bad. The sag is not unreasonable although I will say the CNHL batteries are not the best.

What I believe the issue is partial throttle. The boat is being driven with a ton of partial throttle. That will superheat the motor and to a lesser extent the ESC. If the boat is looking like it will blow over then it needs to be propped down. Try to find a prop that allows you to run at 100% throttle for at least 80% of the time.

You also did not mention what timing was being used.

Be sure to also check that the motor and battery connections are tight and short as possible.

Use the minimum amount of grease as that is a major parasitic drag.

Can you post pics of the interior and driveline.

[Ryanj]

The ripple is not bad. The sag is not unreasonable although I will say the CNHL batteries are not the best.

What I believe the issue is partial throttle. The boat is being driven with a ton of partial throttle. That will superheat the motor and to a lesser extent the ESC. If the boat is looking like it will blow over then it needs to be propped down. Try to find a prop that allows you to run at 100% throttle for at least 80% of the time.

You also did not mention what timing was being used.

Be sure to also check that the motor and battery connections are tight and short as possible.

Use the minimum amount of grease as that is a major parasitic drag.

Can you post pics of the interior and driveline.

When I looked at the settings I found the timing set at 5 degrees. I have just recently changed the setting to 0 degrees.
As to Chnl lipos I have noticed the quality has been going down and for my boats I have been switching to SMC lipos going away from CHNL. My Son is slowly doing the same and his 1/7 here switching batteries soon.
The trottle does make sense to the partial throttle something I can work with his driving to get better with. Smoother throttle pulls.
As the propeller this class were stock with the CNC 5714 and a plastic version. I wish it was optional to have more choices to prop size. Maybe in time have more choices in my club for this spec class.
Grease I normally will mix with marine gear box oil to thin the mix down for less resistance.
Connections are keep as short as possible with use of 8mm Ose battery connectors. Avoiding using a Series connector. Splitting the connectors

I?ll get back with additional photos

[RaceMechaniX]

Nothing sounds too far out there. Next run, make sure to select the temperature so you can log at least the ESC temp.

Are you feeding the motor and ESC with parallel cooling lines? Hopefully no 90 degree fittings in the flow path. Can you see plenty of water coming out the cooling lines when running?