General discussions - FAST RC boat

[BIG TUNA]

Got it. Thanks for the help. What do you think? It looks like I damaged the rotor when I gassed the boat yesterday. The last two pics are the port engine.

 

[BIG TUNA]

While we’re at it. I took the genesis out yesterday and only got 57 mph on 6s with two different battery and prop setups. I tried two props, a dasha.. prop made for the boat and an 45mm aluminum one. Started with the aluminum and puffed a battery. The boat was surging in power. Like a scale boat with a bad fuel pump. Put another set of batts in and dashaboat prop and same 57mph and surging. They were zees 7000mah 120c. Newer batteries. I downloaded the castle app. But don’t know what I’m looking at. I’m thinking I need better batteries?

 

[LibertyMKiii]

This is what I've found.
4 screws from the front, can't tell on the back. Maybe under the sticker?
Use a good set of hex drivers, MIP is preferred. If you strip a screw, you are done.


View attachment 319849
Mystery solved, the end bell is screwed on. Love the videos from this guy, but the first minute is truly a WTF moment

Go to about 5:30 min into the video, and he is taking apart a 2030, identical to yours, just shorter.
You owe me a beer

Nice find!
Man those are tiny motors!!!

While we’re at it. I took the genesis out yesterday and only got 57 mph on 6s with two different battery and prop setups. I tried two props, a dasha.. prop made for the boat and an 45mm aluminum one. Started with the aluminum and puffed a battery. The boat was surging in power. Like a scale boat with a bad fuel pump. Put another set of batts in and dashaboat prop and same 57mph and surging. They were zees 7000mah 120c. Newer batteries. I downloaded the castle app. But don’t know what I’m looking at. I’m thinking I need better batteries?

View attachment 319872

View attachment 319873

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View attachment 319875

I don't see damage on the rotor?

Yes, you have some serious voltage sag going on there. The Castle ESC requires some high-quality Lipos. If you are not looking to break the bank you might want to look at CNHL 70c G+ series. I like the 6000 mAh packs but they are quite wide so double check the dimensions if they will fit. You may have to go with 5000 mAh size that are more standard width cells.

 

[jkflow]

Ok, lots to talk about.
a) Rotors, can't tell from pictures. Is the kevlar wrap damaged? If yes, this typically happens when you overheat the motor (higher than 180F), the epoxy holding the magnets breaks down and the magnets shatter due to the centrifugal force damaging the kevlar wrap. Nothing to repair. TP does sell rotors as a part.
or) If it's only discoloration, fine to use.
Genesis:
Zeeee lipos are your issue. They simply overstate capacity and C-rating. Independent testing shows they are typically only ~70% of advertised capacity and usually in the 15-20C rate.
They won't hold up in boats, they are ok for car bashing and lower loads, but not for high performance applications. You would need ~ 2 in p[parallel in order to get to the right capacity and still have a sub-par c rating (2x)

For boats, I only use SMC, they are cheaper taking the math above into consideration (3x zeee needed and that is too heavy).

On the graph, need to see the 'Amps' with voltage, ripple looks ok i.e. your ESC are holding up well. Else the graphs don't say much other than Zeee collapses under load, which you already know.

Edit CNHL black is ok as well, above 70C on CNHL markings will hold up.

 

[LibertyMKiii]

Edit CNHL black is ok as well, above 70C on CNHL markings will hold up.

For CNHL the black series is ok but the G+ 70c is best.
Some others like the 100c or 120c series are lower output than the 70c. (I know that makes not sense but its the reality)

I pushed my 70c G+ packs routinely in the 500-650 amp range all last year and still are solid packs today.

 

[LibertyMKiii]

The epoxy is still hardening but I got the stuffing tube in, better motor mount, new ESC mount spot, and new battery tray.

The new layout requires a little more aggressive bend in the tube than I like but it should still work just fine. It is hard to see here, but there is the silver piece that fits into the stinger. A short 9/32 tube that is bonded to the hull. Slip-fit inside of that is a normal 1/4" tube for the 3/16" flex cable.

***Disclaimer this boat has been through 5+ setups and is from the 80's nitro/gas era so its not pretty anymore ***
You can barely see it towards the front but I poured in some 2 part-expanding closed-cell foam. This stuff hardens rock solid and will help hold the hull together during 60+ mph crashes.

The new layout allows the lipo to go up front. I installed a 300mm OSE CF battery tray in there which goes waaay into the nose. Its longer than needed, but hey why not. I have mentioned this before, but this new layout allows me to put more weight forward so that I can virtually eliminate the use of the trim tabs. This should net a higher speed with the same setup. The old setup required a lot of trim tab use to keep the nose down.

Old layout for comparison where the battery(s) sit over the rear:

I have Friday and Monday off to make this a 4 day weekend. Hoping to get at least 1-2 days out to test this rig.
Next week I'll pick back up working on the rigger to get it going.

 

[BIG TUNA]

For CNHL the black series is ok but the G+ 70c is best.
Some others like the 100c or 120c series are lower output than the 70c. (I know that makes not sense but its the reality)

I pushed my 70c G+ packs routinely in the 500-650 amp range all last year and still are solid packs today.

I'm not sure the G series will fit my boat. I did purchase some SMC batteries (6) so hopefully I will get some better results. I am going to pickup a few of the cnhl batteries this weekend once I take some measurements. (They have a little sale going on).

The epoxy is still hardening but I got the stuffing tube in, better motor mount, new ESC mount spot, and new battery tray.

The new layout requires a little more aggressive bend in the tube than I like but it should still work just fine. It is hard to see here, but there is the silver piece that fits into the stinger. A short 9/32 tube that is bonded to the hull. Slip-fit inside of that is a normal 1/4" tube for the 3/16" flex cable.

View attachment 319952

***Disclaimer this boat has been through 5+ setups and is from the 80's nitro/gas era so its not pretty anymore ***
You can barely see it towards the front but I poured in some 2 part-expanding closed-cell foam. This stuff hardens rock solid and will help hold the hull together during 60+ mph crashes.

The new layout allows the lipo to go up front. I installed a 300mm OSE CF battery tray in there which goes waaay into the nose. Its longer than needed, but hey why not. I have mentioned this before, but this new layout allows me to put more weight forward so that I can virtually eliminate the use of the trim tabs. This should net a higher speed with the same setup. The old setup required a lot of trim tab use to keep the nose down.

View attachment 319953


Old layout for comparison where the battery(s) sit over the rear:

View attachment 319954

I have Friday and Monday off to make this a 4 day weekend. Hoping to get at least 1-2 days out to test this rig.
Next week I'll pick back up working on the rigger to get it going.

I might have missed it but what electronics are you running in the boat? Also, how big is the boat? I have an old 57" enforcer I am thinking of converting to electric.

 

[LibertyMKiii]

I'm not sure the G series will fit my boat. I did purchase some SMC batteries (6) so hopefully I will get some better results. I am going to pickup a few of the cnhl batteries this weekend once I take some measurements. (They have a little sale going on).

I might have missed it but what electronics are you running in the boat? Also, how big is the boat? I have an old 57" enforcer I am thinking of converting to electric.

Mine is an unknown 42" boat from the late 80's. It has an XLX2 and TP4070. A Castle Hydra would work good and probably would want a 56 series motor for a big boat like that enforcer.

Very timely about the lipo quality. I made some runs this morning on 4s and 6s.

First up the 4s is top tier Onyx RC Power systems 8,000 mAh.
Notice on these how little the voltage dropped. Bright red line is the voltage, it started at 16.4 and under load at peak speed finished at 14.4v. About a 2 volt drop while holding under a 334 amp load. This was 63 mph.

Next is low tier LiPo.
This is a 5500 mAh 45c Jims Ace 6s Lipo. (going 4s to 6s should be much faster right?)
It fell on its face so hard LOL. From 24v down to 12.1v and even when the amps went way down to 276 amps it still didnt come back up at all.
This 6s run was 66 mph only 3 mph faster than the 4s run before it. The most amazing part is how the RPMs were going down as I held full throttle because the voltage kept falling.

Next time out I'll bring my CHNH G+ 70c 3s packs and the Onyx 6600 LHB 3s packs to run in series for 6s and compare. It should go well past 75 mph with those LiPos.

 

[BIG TUNA]

63 mph seems great on 4s with a heavy built boat. What kv is the motor, and is it just a saw run boat or can you run it around and not get too hot at that speed?

 

[jkflow]

Wow, those currents are not sustainable, I'd consider a 12S setup.

 

[BIG TUNA]

I was going to reassemble the motors and one of the rotors has this blue on it. The other does not. Do you think I melted something?

 

[jkflow]

No, that is glue that holds Kevlar in place, perfectly fine.

 

[ActionJackson]

Great write up on the LiPo comparison Liberty! …crazy how that cheap 6s dropped to a lower under load 12.1V voltage level than the better 4s at only dropping down to 14.4V under load!!!

 

[LibertyMKiii]

Great write up on the LiPo comparison Liberty! …crazy how that cheap 6s dropped to a lower under load 12.1V voltage level than the better 4s at only dropping down to 14.4V under load!!!

Continued on that today.
Really amazing comparison and landed a PB of 90 mph with this mono!

 

[LibertyMKiii]

63 mph seems great on 4s with a heavy built boat. What kv is the motor, and is it just a saw run boat or can you run it around and not get too hot at that speed?

It can do 2 runs max and gets hot.
SAW only.
Higher kv for SAW use.

For normal use I ran 1650kv on 6s and was around 60 mph for it to run cool.
In general anything north of 60 mph is going to generate significant heat on a mono due to all the drag and power it requires.

 

[Senton_Prime]

What's SAW!?

 

[jkflow]

Nice runs!
SAW - Straight Away racing

 

[ActionJackson]

Continued on that today.
Really amazing comparison and landed a PB of 90 mph with this mono!

Nice man! Heading towards triple digits soon

 

[LibertyMKiii]

Nice man! Heading towards triple digits soon

Thanks man, this is my current focus.
I know now it will do 100+ mph

The guy running the gps speed record site found my video and put me in the #2 spot for mono hulls

https://gpsspeedrun.com/speedlist/2023

 

[Notoriousone]

Nice, I didn't know about GPSspeedrun.com, cool site.. I may have to submit my Zonda 112mph run. I see they have a class for stock Cats