Venom/Atomik New 58 Inch Electric Catamaran

[Chris Nicastro]

wonder what the real Watts of this system are



what is X?
we are being told 5000mah 25c packs are more than enough for this boat at WOT
and we were told that is 100amps cont.. if so 25c won't cut it

lots of racers including myself understand the water conditions effects how a boat runs and the loads on the esc/motor/batteries

from your postings this boat can't take WOT turns so now in this thread we are reading two different out comes of this RTR
plus runtimes are more than doubled for letting off in the turns??

only posting some thoughts that I have and possibly others as well

I want a big cat

Well I'm not sure what to tell you, you'll just have to try it.

One of our employees bought an ARC and took it home over the long weekend and reported a 14.55min run time just playing around with it in choppy and windy conditions and being cautious. He ran a new 6S 25C 5000mah pack. He is a typical newcomer to big electrics so this is an example of the type of use and run times we should see. As a customer gets confident and faster with the boat things will change.

If you look at a data log graph when this boat is driven the peak amps hit at the pull of the trigger and taper off, its not a continuous high load. When you let off to turn the boat will coast so it reads nearly zero load and then the cycle starts again. So the added run time is from the fact that the load is not perfectly continuous coupled with the driving style you end up with more time than the straight math predicts.

In testing the 50C packs for sure are way better than the 25C packs but the point is the boat works fine with the least expensive packs too.

[EricSchlaifer]

Right on Eric
And I think the 1180kv version he sells is what comes in this boat (aka 1200kv)
And again only 55bucks

The boat comes with an 1100KV. I'm not sure who's making these motors for Venom, but it looks like an overgrown version of their other outrunners. The guys at Venom have told me that they are working on some factory upgrades for the motor/ESC for this boat. I'm hoping to have a good package to recomend to my customers soon. I would really like to get this boat past 50mph, but still keep a decent runtime. Right now my run times have been all over the place! Depending on the water conditions, strut angle, and driver I have seen runtimes between 5-12 minutes! Admittedly, I have a lot more real boat experience than RC boat experience. But, I was still pretty surprised to see so much variation. My friend ran his yesterday with what I felt was way too much strut angle. He had a 6 foot tall roost and would cavitate pretty badly getting on plane...had to really roll into the throttle. We did see the fastest top speed though, but the shortest run time - 5 min. It's why I'm so anxious to try to improve the CG. I also need to find my GPS. The boat did walk past his stock MG, so i'm pretty confident it is capable of 40+ out of the box.

Are boats like similar to most other electrics where its preferable to achiever rpms with higher volts/lower kv's, or vice versa? What is that seaking 120amp esc good for kv wise in everyone's opinion?

[Chris Nicastro]

The ARC hull is the same as the gas boats we offer so the CG position is the same if you have any experience with the gas version.
If you set the CG up by the total length at a certain % then it will end up nose heavy. If you set the CG up with the wet hull length then the CG will be more accurate. I balance the hull at about 30mm ahead of the rear step and the hull runs pretty dry. The prop depth is aligned with the lowest edge of the sponsons, maximum. The angle is usually 0deg. and the boat runs OK like this. This hull has a good tunnel height and gets lighter with speed so depending on the days conditions you should set the drive angle and CG as needed.

[Chris Nicastro]

The boat comes with an 1100KV. I'm not sure who's making these motors for Venom, but it looks like an overgrown version of their other outrunners. The guys at Venom have told me that they are working on some factory upgrades for the motor/ESC for this boat. I'm hoping to have a good package to recomend to my customers soon. I would really like to get this boat past 50mph, but still keep a decent runtime. Right now my run times have been all over the place! Depending on the water conditions, strut angle, and driver I have seen runtimes between 5-12 minutes! Admittedly, I have a lot more real boat experience than RC boat experience. But, I was still pretty surprised to see so much variation. My friend ran his yesterday with what I felt was way too much strut angle. He had a 6 foot tall roost and would cavitate pretty badly getting on plane...had to really roll into the throttle. We did see the fastest top speed though, but the shortest run time - 5 min. It's why I'm so anxious to try to improve the CG. I also need to find my GPS. The boat did walk past his stock MG, so i'm pretty confident it is capable of 40+ out of the box.

Are boats like similar to most other electrics where its preferable to achiever rpms with higher volts/lower kv's, or vice versa? What is that seaking 120amp esc good for kv wise in everyone's opinion?

The KV value is not the best way to go about this, you need to measure the load. The prop choice with any motor and ESC combo will make or break the set up. So even if the guys chime in with a KV suggestion it has to come with a prop and peak Amps info to be relevant. The ESC is rated to 120A cont. and up to 6S. That peak power value is 120A X 25.2V = 3024Watts That is the combos max potential output. That amount of watts puts us at nearly twice the HP of the typical stock Zenoah 26cc engine.
With 1100KV and the 54mm prop this combo on 6S is well matched to the 120A ESC with a margin of safety. With off the shelf components and some testing you will find a better more powerful combo for sure and go faster than the stock boat. If you test with different props you might find a little better top speed on the stock set up but you run the risk of blowing the ESC.

No matter what you do please test with a data logger to help you zero in on a set up while seeing exactly whats going on each run. Better yet if you have telemetry.

[EricSchlaifer]

The ARC hull is the same as the gas boats we offer so the CG position is the same if you have any experience with the gas version.
If you set the CG up by the total length at a certain % then it will end up nose heavy. If you set the CG up with the wet hull length then the CG will be more accurate. I balance the hull at about 30mm ahead of the rear step and the hull runs pretty dry. The prop depth is aligned with the lowest edge of the sponsons, maximum. The angle is usually 0deg. and the boat runs OK like this. This hull has a good tunnel height and gets lighter with speed so depending on the days conditions you should set the drive angle and CG as needed.

Thanks Chris. I was running 0%, with the depth as you described (I have not strayed from those settings on my boat yet). It ran a tad wet for me with the battery in the stock position. I just checked CG and we are referencing the same point. I haven't confirmed it yet, but I suspect my friend had too little prop depth. And you are correct, at that point the hull is very stable. My boat got runtimes between 8-10 minutes. I had little to no cavitation, even when just stabbing the throttle. The boat planed easily too.

[EricSchlaifer]

The KV value is not the best way to go about this, you need to measure the load. The prop choice with any motor and ESC combo will make or break the set up. So even if the guys chime in with a KV suggestion it has to come with a prop and peak Amps info to be relevant. The ESC is rated to 120A cont. and up to 6S. That peak power value is 120A X 25.2V = 3024Watts That is the combos max potential output. That amount of watts puts us at nearly twice the HP of the typical stock Zenoah 26cc engine.
With 1100KV and the 54mm prop this combo on 6S is well matched to the 120A ESC with a margin of safety. With off the shelf components and some testing you will find a better more powerful combo for sure and go faster than the stock boat. If you test with different props you might find a little better top speed on the stock set up but you run the risk of blowing the ESC.

No matter what you do please test with a data logger to help you zero in on a set up while seeing exactly whats going on each run. Better yet if you have telemetry.

Thanks again Chris :) I do have a receiver with telemetry that I was planning on running with when I test the new 12S combo that I am working on, still trying to decide on ESC. But, that is still very much in the research stage. A data logger is a must! I'm not a fan of blowing up gear to determine that I have pushed it too far I plan on running the boat stock while I acquire the right gear to set up 12S. The only mod i'm planning on immediatly is dual packs in the sponsons.

[Chris Nicastro]

For your 12S test try to target 30,000RPM at peak values and go from there.
30000/50.4V = 595KV. With 20% losses you will see roughly 24000RPM at the prop. If you want more RPM then do the math to achieve 30000RPM after 20% losses. The trouble is with more RPM the prop size drops and the amps begin to pile on so I usually target 30000RPM after losses and adjust accordingly.
The ARC is set up at 27720 peak RPM and roughly 22000 to 23000 rpm at the prop. I have tested smaller props and more RPM and the boat suffers getting out of the hole and on step. Once on step the speed is great and we have gone over 50mph.

We will have a plug and play option set for 12S soon.

[Brushless55]

Well I'm not sure what to tell you, you'll just have to try it.

One of our employees bought an ARC and took it home over the long weekend and reported a 14.55min run time just playing around with it in choppy and windy conditions and being cautious. He ran a new 6S 25C 5000mah pack. He is a typical newcomer to big electrics so this is an example of the type of use and run times we should see. As a customer gets confident and faster with the boat things will change.

If you look at a data log graph when this boat is driven the peak amps hit at the pull of the trigger and taper off, its not a continuous high load. When you let off to turn the boat will coast so it reads nearly zero load and then the cycle starts again. So the added run time is from the fact that the load is not perfectly continuous coupled with the driving style you end up with more time than the straight math predicts.

In testing the 50C packs for sure are way better than the 25C packs but the point is the boat works fine with the least expensive packs too.

your preaching to the choir on the full throttle off the throttle stuff
100amp cont will toast a 25c pack
and the math still does not compute with the 100amp cont WOT vs 14.55min runtimes
you cant be off the throttle that much with a system said to deliver 2000watts and still get almost 15min rutimes while sport runing ??
14.55min x 6s = only 16.5amps = 366watts!

my race boats see 2.75min and maybe a little more racing and close to 4.5min max for sport running, and that's with lots of slowing in the corners and splashing my friends on the shores

The boat comes with an 1100KV. I'm not sure who's making these motors for Venom, but it looks like an overgrown version of their other outrunners. The guys at Venom have told me that they are working on some factory upgrades for the motor/ESC for this boat. I'm hoping to have a good package to recomend to my customers soon. I would really like to get this boat past 50mph, but still keep a decent runtime. I also need to find my GPS. The boat did walk past his stock MG, so i'm pretty confident it is capable of 40+ out of the box.

Are boats like similar to most other electrics where its preferable to achiever rpms with higher volts/lower kv's, or vice versa? What is that seaking 120amp esc good for kv wise in everyone's opinion?

the specs say 1200kv same as the FC version for much much less than venoms price
and stick with fightercat on the electronic upgrades.. the venom stuff will be over priced vs his
save your money on this bro

The ARC hull is the same as the gas boats we offer so the CG position is the same if you have any experience with the gas version.
If you set the CG up by the total length at a certain % then it will end up nose heavy. If you set the CG up with the wet hull length then the CG will be more accurate. I balance the hull at about 30mm ahead of the rear step and the hull runs pretty dry. The prop depth is aligned with the lowest edge of the sponsons, maximum. The angle is usually 0deg. and the boat runs OK like this. This hull has a good tunnel height and gets lighter with speed so depending on the days conditions you should set the drive angle and CG as needed.

every racer I know and all on these forums take mesurements from the back of the hull.. not from the rudder or stut

The KV value is not the best way to go about this, you need to measure the load. The prop choice with any motor and ESC combo will make or break the set up. So even if the guys chime in with a KV suggestion it has to come with a prop and peak Amps info to be relevant. The ESC is rated to 120A cont. and up to 6S. That peak power value is 120A X 25.2V = 3024Watts That is the combos max potential output. That amount of watts puts us at nearly twice the HP of the typical stock Zenoah 26cc engine.
With 1100KV and the 54mm prop this combo on 6S is well matched to the 120A ESC with a margin of safety. With off the shelf components and some testing you will find a better more powerful combo for sure and go faster than the stock boat. If you test with different props you might find a little better top speed on the stock set up but you run the risk of blowing the ESC.

uh we are many steps ahead here..
going lower KV with more volts = more efficiency = cooler running electronics and longer rutimes
KV value is very important for putting together a great running setup

and one cannot compare a gas motor to a esc for power.. the motor only draws what it needs to run and no more

Thanks Chris. I was running 0%, with the depth as you described (I have not strayed from those settings on my boat yet). It ran a tad wet for me with the battery in the stock position. I just checked CG and we are referencing the same point. I haven't confirmed it yet, but I suspect my friend had too little prop depth. And you are correct, at that point the hull is very stable. My boat got runtimes between 8-10 minutes. I had little to no cavitation, even when just stabbing the throttle. The boat planed easily too.

your at about 24 to 30 amps = 533 to 667 watts

For your 12S test try to target 30,000RPM at peak values and go from there.
30000/50.4V = 595KV. With 20% losses you will see roughly 24000RPM at the prop. If you want more RPM then do the math to achieve 30000RPM after 20% losses. The trouble is with more RPM the prop size drops and the amps begin to pile on so I usually target 30000RPM after losses and adjust accordingly.
The ARC is set up at 27720 peak RPM and roughly 22000 to 23000 rpm at the prop. I have tested smaller props and more RPM and the boat suffers getting out of the hole and on step. Once on step the speed is great and we have gone over 50mph.

We will have a plug and play option set for 12S soon.

30k taget on 12s may not be the best for a big cat like this..
many run much lower rpms on a rig this size and get great results
uh where is the load (peak amps) and prop sizes?

have a great day

[EricSchlaifer]

Brushless,
I'm probably going to head out with my buddy and his ARC today. I will time a run at WOT the whole time and let you know the run time (after I fix the prop adjustments of course).

[Chris Nicastro]

I think your mistaking or misquoting the peak value for constant value (actually average load value).The boats power system at nominal values is over 2000W etc. What you actually use to get around isn't always 2000W. The system is capable of 3000W using peak values technically but rather than use that value we understated it using nominal power.

Running a 25C 5000mah pack at 100A continuous is under its specified limit of 125A. Is it recommended you run a battery pack under that condition...not if you don't know what your doing, period. Is that what we are saying here? No we are not. We do load test our battery packs here in house with scientific equipment and in practical test models to meet our minimum requirements. We are very well versed in LiPO usage, testing and applications.

As for hull CG you can measure it from anywhere you want as long as you are consistent about it. It screws other people up if you use a nonstandard method but that's about it. One guys 35% can be another guys 30% as long as they know that....who cares? I measure from the transom of the wet hull. If there is an excessive overhang then you can bring other math into it and calculate moments of inertia to determine CG, do we have to split atoms here? No.

When it comes to set up and electronics choices there are many ways you can go about that. I start with the target RPM to determine the motor to try. From experience or other data I know what ESC to try. Until I put it in the water with a data logger I always go for the smallest prop to establish a base line A/W/V reading. Then I adjust things from there.
Can you show me how to predict amp loads in water without knowing any info before hand?

And... umm... yes you can compare a gas engines power to a brushless system because there are mathematical relations to draw comparisons from.

As I stated a KV value alone is not info to go on because its part of a system...need more info. like a baseline test or practical data from an identical set up, etc. He asked for just a KV recommendation only.

Also these cats are for straight line open water style racing boats not high speed tight turns. Watch full scale or even the Europeans race with their RC 60 to 92in cats and they always slow down in the turns and power back out. The guys that race cats in ovals would not like this hull for that application. Run this ARC hull as a class and its a different story.

Rather than pick this boat apart with your many questions and arguments lets just agree this is probably not the boat for you and move on. You race boats, thats fine, this is not a race boat like you run.

[rawsonreyes]

solving problems is better than critique

hi guys i read the forum what i think is why not give your expertise on a proper setup mr 55 so guys who has the boat will get it running better, thanks to you and the venom guys may seek your help on their next project.i have been in boating for over 20yrs and still learning so for the love of the sport lets all work together for the general improvement of model boating,we can share knowledge,that's what we would all want i guess, and get better run times and more speed for less price.think it's a nice project from venom/atomic and hope they keep trying.it will always have unsatisfied people but sometimes it helps improve things when looked at all possibilities.

[Brushless55]

1)I think your mistaking or misquoting the peak value for constant value (actually average load value).The boats power system at nominal values is over 2000W etc. What you actually use to get around isn't always 2000W. The system is capable of 3000W using peak values technically but rather than use that value we understated it using nominal power.

2)Running a 25C 5000mah pack at 100A continuous is under its specified limit of 125A. Is it recommended you run a battery pack under that condition...not if you don't know what your doing, period. Is that what we are saying here? No we are not. We do load test our battery packs here in house with scientific equipment and in practical test models to meet our minimum requirements. We are very well versed in LiPO usage, testing and applications.

3)As for hull CG you can measure it from anywhere you want as long as you are consistent about it. It screws other people up if you use a nonstandard method but that's about it. One guys 35% can be another guys 30% as long as they know that....who cares? I measure from the transom of the wet hull. If there is an excessive overhang then you can bring other math into it and calculate moments of inertia to determine CG, do we have to split atoms here? No.

4)When it comes to set up and electronics choices there are many ways you can go about that. I start with the target RPM to determine the motor to try. From experience or other data I know what ESC to try. Until I put it in the water with a data logger I always go for the smallest prop to establish a base line A/W/V reading. Then I adjust things from there.
Can you show me how to predict amp loads in water without knowing any info before hand?

5)And... umm... yes you can compare a gas engines power to a brushless system because there are mathematical relations to draw comparisons from.

6)As I stated a KV value alone is not info to go on because its part of a system...need more info. like a baseline test or practical data from an identical set up, etc. He asked for just a KV recommendation only.

7)Also these cats are for straight line open water style racing boats not high speed tight turns. Watch full scale or even the Europeans race with their RC 60 to 92in cats and they always slow down in the turns and power back out. The guys that race cats in ovals would not like this hull for that application. Run this ARC hull as a class and its a different story.

8)Rather than pick this boat apart with your many questions and arguments lets just agree this is probably not the boat for you and move on. You race boats, thats fine, this is not a race boat like you run.

1) not my mistake, but from a Venom reps quote of 100amps cont. here on OSE..
2000watts / 6s = 90amps and that part is cool
reality sounds more like 50-60amps cont = 1100 to 1300watts with runtimes to follow of about 5min and that is a decent time, actually great time for a hull this size

2) pulling a constant 100amps through a 5000mah 25c pack is very hard on it and could spell problems with constant use.. most packs are over rated and cant deliver true C rated power
jsut saying..

3) Who cares? well we all do on CG placement.. most if not all use the transom as the starting point when measuring for cg IMO

4) not me but you were the one from the earlier post saying we needed loads first before we could give any advice.. just following what you said
no way to really come up with that figure unless we put it in the water and I agree on that..

5) uhhmmmm, not by what you posted earlier.. you cannot compare an esc rating to a gas motor...
my P-Spec racer uses a esc rated to over 4000watts, does that mean I have almost 5 1/2hp? no not at all.. you need the motor that pulls the amps / 746 watts = 1hp
that is not determined by the esc but the motor.. and you need like you said an esc that can take the amps adn I agree

6) how can you get practical data with out trying something first.. kinda goes back to #4 ( a big quoted contradiction sort a )

7) I agree these are more suited for straigh line runs vs actual racing.. I know because I owned a GAS KOS (if it's anything like that hull).. check my albums
I agree, having 5 or more on a course and it would be a blast!!

8) I have every right to ask all questions I want.. this is after all a free open forum!
just reading very carefully of what is being posted by venom and others about this new boat, and things don't line up

again have a great day.. I would love to be a high altitude tester for this boat!
the waters are fast up here ya know!

[rawsonreyes]

hi mr 55 just buy one test it if it don't work to your liking sell it. asking all the questions is your right but giving pro answers is even greater,simply put make recommendations for improvement on the boat.it don't matter who's wrong or right but getting the end results corrected.

[rawsonreyes]

what's the cost of the boat and where can it be found.that would be good info to start with.

[Brushless55]

what's the cost of the boat and where can it be found.that would be good info to start with.

That info (link) is on the first page of this thread I think..