50" Thunderbolt with twins

[FastVee]

Hi all,my next build will be the Thunderbolt cat.

Just waiting for the hull, should be here in few days.



Since the 58" Navaho twin build I did few years ago I have really started to like outrunners and most likely will use these in this build also.

I am on relatively small budget on this build also, but will get a bit better esc´s .



Now I am still thinking if the 180A seaking would be good enough or maybe the HV version would be better (this), will see kind of depends of the motors and batteries but I would like to hear your opinions.


I belive that 6s and these 1250kv

or 12s and these 530kv

Both have quite good power (3,9-4.25kw ) compared to the 910kv 3kw ones I have on the navaho. The H37404 I used on the Navaho are still working well and they are one option to use on this build also( these ) .

The Navaho is about 50mph boat right now with pretty warm motors ,trying to build this smaller cat with faster speed and long run times in mind. -I´d say about 60 mph is the goal but if it ends up going faster then that is no problem...


So what do you think of my plans and what would you change?


Thanks for looking,

-Pate

[lenny]

How you doing over there,
Any new video's like of the 58" Navaho twin build ?
Looking forward to this one and some video's to.

[FastVee]

Hi Lenny! I´m fine thanks 4 asking, how r u doing?

I have one vid of the navaho from this summer,

Just a test of diff batts and new layout inside(moved the motors really back),no pics other then what the vid shows -and the new look also! .

edit. moved the vid to the navaho build thread ,trying to keep this one on topic...

-Pate

[iridebikes247]

If you're truly set on out runners then that motor with 6s2p and seaking 180 will probably be fine. Personally I would spend a bit more and buy the sirius 1717 that keithbradleyboats.com sells. Outrunners are cool provided cooling is enough. seaking 180 will be fine for 6s.

http://www.scorpionsystem.com/catalog/motors/hk40/hk4035/HK-4035-800/

similar in size to the scorpion too.

[FastVee]

Just received the hull few hours ago.

Will do some cosmetic changes to it and new carbon inlay over the layer that was on from factory.

Actually allready started with the mods, 3 air intakes are off

Notice the jet boat in the hull, this is proper size cat!

[FastVee]

Got the inlay done, 200g matt.

Also started to fill the intakes

[Chrisg81983]

Looks great I would consider using leopard 5692 around 900 kv even 1000kv depending on what you really want out of her. Personally I would go for the tp 5850 1000kv on 10s or even 8s for just a fun boat and a sf 240 or 300

[FastVee]

Funny you mentioned leos, I have looked at the 5692´s and even higher kv should work with the 180A esc´s.

Just not sure if I want to go 70-80mph or just sport boating.

A mate of mine could supply me sss line of motors and I hear they are even more efficient then leos but the amp ratings are riddiculous cant be true but since I cant know for sure then I was thinking about the outrunners cause I know about them quite a bit.

(5696 sss motor max A rating is close to 300A)

[iridebikes247]

I feel like I have seen 5692 1340kv motors with seaking 180 escs, as a twin this setup will surely get you moving. With this boat you could run a big single setup with a sf240. I wouldn't pay attention to the amp ratings on that horracing.com site any motor will pull a lot of amps if the setup is wrong.

http://www.himodel.com/electric/LEOPARD_5682_1360KV_4-Poles_Inrunner_Brushless_Motor_Red_for_1_5_Cars_LBP5682_2Y.html

I haven't personally dealt with the above but the boat will run like 55-60mph with the above motors on 6s.

[FastVee]

The leo I was looking at was this ,1340kv also but longer can

2 should be ok and the amp draw should be pretty low also with these.

The amp rating of the sss motors I was talking about is from this list
1.JPG

Do you know anything about the sss motors? -are they any good , these would be cheaper then leos but that amp rating (and 12kw power rating) just makes me think this is nowhere close to true amps or watts...

-Pate

[Chrisg81983]

You really cant go off advertised amp draw it is really different in real situations especially in boats. When I ran a 5692 1090kv on 8s with a 462 prop the amp draw was about 300 amps give or take. I would run a twin 5692 with sf 240. The t180 are not going to make it on low cell count and high kv with these big motors. The t180 is a sick esc with a 40 size motor. Actually they are almost bulletproof in the rite situations.

[FastVee]

That is true that true amps can be anything.

I guess I´ll better go with the outrunner setup, the 200A suppos have been barely warm with the 58" boat with the 910kv outrunners and 57mm props. Top speed on that boat has been 50mph so I cant see problem getting this smaller cat to go faster with same amp draw. -and the 200a suppos are known to be about true 120A escs so the t180s should be fine.

But like we know, boats can surprise with low amps high speed or just the opposite. When I built the Navaho almost every1 told me that the 58" v hull would not go anywhere with the electrics I installed and it is still going strong after over 2 years. -and only 6s1p 5000 25c packs that are now 3 year old!

Best bet could be the same motors I have on the big boat I guess...

Here is a pic of the 2. (dont mind the messy shed) -the cat is bigger then what I thought next to the navaho but the overhang makes it look bigger. and few images of the 5000mah 25c 6s packs inside the hull to show the available space
2.JPG
1.JPG

shed1.JPG

-Pate

[bill34207]

Hi Pate
Got your PM and dropping by. For longer run times I'd really suggest going to the higher voltage setup over 6s. That was one of very few complaints with my Thunderbolt. (aside from the horrible seam lines) Once I started getting comfortable with it and seeing more WOT, the run times started coming down.
With the abundance of space under the hatch you might even want to consider using a twin strut setup opposed to stingers on the sponsons like I did.
Reference this thread on RCG. With all that room under the hatch it would be easy enough to do and would leave plenty of room in the sponsons for your battery packs.

[FastVee]

Hi Bill, thanks for replying.

I would think about the struts but actually I allready have stingers I ordered just for this build.

The 58" Navaho build I keep referring to that I did few years ago with outrunners made me think that this should be pretty easy to make 60mph boat with just cheap outrunners and such since this is smaller boat and the Navaho is 50mph boat 3min runtime with 5517/3 props or 45mph and 7-8minutes runtime with k57 props and just 6s1p 5000 pack per motor.-and the motors are rated only 3kw.

I will think about the hi voltage setup also, just cant afford the high cost esc´s, the 130A seaking 12s versions are pretty much my limit on this build. -or the 180a 6s units.

maybe 10s1p could work with lower kv motors and use bigger props to get to speed...

You did give me something to think about...



-Pate

[bill34207]

I know what you're saying about the high price of HV ESC's. It is the best way to cut down on amp draw though.
I could get pretty close to 3 minutes run time on mine even after getting comfortable with it so 6s should work for you as well. I think part of my problem was that the inside (I think) esc would thermal after about 6 hard laps. By the time I'd get back to shore both would be working so can't say for sure but the inboard motor & esc always tended to run warmer.
Reducing the distance between the props help alleviate some of the "posi trac" effect on the drive line (& electronics) and makes it easier to corner. I would have liked to build my little Cheetah twin that way but there just wasn't enough clearance between the tunnel floor and the hatch. I can prop up to a pair of 447's on it and get about 65 out of 6s but it will not turn at the end of the straight unless you let off a little. With 442's it will corner at full throttle.