Best prop question????

[TINY]

Probably been asked a thousand times but im after outright speed, the 55" arrow shark cat doesn't turn real good..

Motors are 2 x leopard 4082 1600kv

2 x swordfish 200amp esc

2x 6s 35 to 75c

sharts are running opposed but could be changed if needed..

Cheers justin

[sanyijr]

Tiny,

Not-so-Tiny setup. Sorry, out of my relm of knowledge.... But I am curious to see suggestions.

Sean

[TINY]

Been given suggesstions of x447 and 450 3blade but they look so small for motor?? And big boat....Just want it to go real fast and turn when i cant see it....lol

[Boaterguy]

let me Change my post to please the general community.
on alot of twin cat build threads, I see people talking about which is better, inwards or outwards.
try changing it and see if it helps.

[LarrysDrifter]

Boaterguy, what set up do you have in your twin drive cat? What is the rotation of the drives? Do you give your bad and misleading information based on what you read or your experience?

[Fluid]

How fast do you want to go? What are the details of your packs (1P or 2P, brand, capacity, "C" rating)? How much does the boat weigh? Those motors and ESCs will only take so much abuse, especially with low performance packs. In "theory" the x447s would probably max out near 55 mph, but I suspect they are too small for a 55" hull. To go much faster you'll need bigger diameter and more pitch (and thus more amps) but the motors, packs and ESCs may not be up for it. With top-end components I'd run x457s but they'd likely melt yours.

Turning has a lot to do with the rudder used. The brand of rudder, how much is below the bottom of the sponsons, and a photo or two of the transom area would help us to diagnose.


.

[TINY]

How fast? as fast as possible... c rating is 35 to 75 as stated.. Capacity is 5000mah Turnigy nanotech.. motor is 4 pole.. does any of that help.. Its a 55' glass cat with 2 batts 2 200amp esc 2 motors and alloy hardware.. also a couple of pool noodles.. 1 or 2p? (what does that mean)

Will the motors handle 12s and high volt esc's?? thought the 4082 1600's were pretty good?
Cheers

How fast do you want to go? What are the details of your packs (1P or 2P, brand, capacity, "C" rating)? How much does the boat weigh? Those motors and ESCs will only take so much abuse, especially with low performance packs. In "theory" the x447s would probably max out near 55 mph, but I suspect they are too small for a 55" hull. To go much faster you'll need bigger diameter and more pitch (and thus more amps) but the motors, packs and ESCs may not be up for it. With top-end components I'd run x457s but they'd likely melt yours.

Turning has a lot to do with the rudder used. The brand of rudder, how much is below the bottom of the sponsons, and a photo or two of the transom area would help us to diagnose.


.

[tiqueman]

Oh my.. we have a lot to talk about. No, a 1600kv motor cannot take 12s. Thats over 70,000 rpm. 1P is the set up most ready to runs use and what most people sport boat with. It for example is a 4S pack. or (2) 2s packs series to 4S would be 4S1P. 2P is parallel set ups. 4S2P would be (2) 4S packs wired in parallel to give you the same 14.8V output.. but your mah doubles.

From experience I have a 45" cat doing mid 70s on 1600KV castles (roughly 4085ish i think) Castle 1520s, and turning 447s. That was running 6S1P per side. The cat you have obviously is 10" longer and much more stout, but I dont see why 60 would be a problem. and turn 447s.

Oh and leopards are pretty good, but even a NEU will let go and toast at 70k rpm.

And one more thing. Every hull is different when it comes to "in" vs "out" rotation of props. I have two hulls that it doesnt really seem to matter that much on. My HPR runs WAY better with them spinning out. Another guy whos in the club has and expresscraft MTI and it also likes out. He just built a DF twin cat and it was all over the place while spinning out, hw changed them to in and its a totally different controllable boat. So testing is all you can do. Try both and see which is better.

[TINY]

Ok i run 2 6spacks (1p) I thought it was kv mutiplied by cells but it sounds like kv multiplied by cell voltage.? is that correct.. Makes sense now.. 35k was my target rpm So if i went up to 5 series leopard and 600-800kv ish i could run bigger and better props with a higher speed at 12s??

[tiqueman]

2 6s packs together for 1P would be 12S or 44.4 volts.

Yes KV is multiplied by final voltage for your unloaded rpm value. And yes again, your still spinning the same rpm, but your amp draw would go down and able you to swing a larger prop. therefore, a bit faster. Your on the right track now.

[6BOOST]

Are you distinctly set on on running twins? I know most people like twins on big cats, but for your goals, a single 2028 castle, fightercat 16s/200a speedy and 12s would net you 60+mph for probably less cost and a hell of a lot less hassle, 50+" mono's have gone over 70mph with one of these one 12s. Not trying to move the goalposts for you, but when your knowledge is limited the K.I.S.S principal imo would net your more enjoyment for less hassle till you get a handle on it all and with the same outright speed. I don't know if you already have speedy's, but your battery packs can still be used:)

6BOOST

[TINY]

Thanks for your reply's guys and your right I'm new to elecs and used to hate elec and nitro? I raced a TS 30.5 carbon baja that cost me a fortune.. It wasn't untill I saw a mates e revo done up that I grew a respect for electrics.. I've had fast 1:1 cars bikes and boats so I'm happy to pursue the smaller scale stuff. My goal is 80 mph with a big cat. Not interested in oval racing or similar.. Just outright speed!! I just need the combo and I can order and assemble. I'm not being cocky guy's but when you spend over 8k on a buggy then two or three on a boat suits me fine since I now live near alot of lakes and have a new respect for boats...
Cheers justin

[6BOOST]

To run 80mph in a 55" cat your going to need much more then 4082's imo, at least to do it more than once lol. There is a few motor options, single NEU2230, twin 5698 or TP power 5660 or twin castle 2028. Ultimately the first 3 will cost similar money as the money saved on batteries, speed controllers and drives on the single, will cost you extra on the higher quality 2230, the twin 2028's will be a little more expensive, as the motors are about $100 each more expensive than the other twins.

If you want a reliable 80mph, then you can double your estimation by the time you have it in the water, for that sort of money if you don have the hull already maybe consider going down to a 32-41" cat with something like a NEU 1527 which Steve has on special here in the store atm and 80mph might be possible within your budget.

6BOOST

[TINY]

I've got everything already but will need bigger speedy's and motors.. If i was going to run twin castle 2230 or 2028's the what sort of props should i be getting made up..

All drive line is installed, dual stinger etc etc

[Fluid]

An 80 mph cat just 32" long is not for everyone. It will not run that fast on anything but reasonably smooth water, and run time will be short. Believe me, I know better than anyone else.

A club member made a 44" HPR cat go into the 80s (on GPS) with twin 1527 Neus and 10S2P/5000 mAh. He still needed reasonably smooth water but it worked well for him. The guy was an experienced FE builder though, and I do not recommend any new FE boater start with a 55" boat!!

If the OP really wants a 55" 80 mph twin cat it will cost him. The old addage is true: Speed, low cost, reliability - pick any two. Even then you will not be able to run that fast in very rough water, and amp draw will be high if you use the 80 mph capability. The Castle 2280 does not have the Kv needed for 80 mph on 10S. I doubt that the smaller Neu 1527s will work in a 55" boat, 2230s are a better choice with Kvs around 1000. Then ESCs - Schulze 40-160s are the gold standard, but based on what I have seen with my Castle HydraICE controllers the HV version may work well....whenever it comes back on the market.

Your packs are marginal at best. I have seen Turnigy packs burst into flame (literally!) after two minutes run time in a 42" mono running 55 mph on 10S. It is tough for some new boaters to grasp, but ALL the power in an FE boat is in the packs. Period. Better motors just stress the pack harder. The better the pack quality, the faster the 10S boat. Inadequate packs will not only slow the boat down and risk a fire, they can and will take out an ESC due to high ripple currents.

I wish you luck, just go slowly and plan on making the first trip to the pond a learning experience. Go slowly even though you will be very excited. Don't bring along a crowd. Don't plan on reaching 80 mph, put on smaller props and aim for 50s or 60s. Run for no more than one minute, then bring it in to check temps. Send it out for another minute, then check again. This is tedious but it can save you from making a very costly mistake. You'll thank me.


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