Drum Roll Please It's the BJ II

[RCprince]

I thought I'd share this with you guys....with a lilttle bit of time on my hand Here is my new 30 inch BJ New Cowling, Trim Tabs, Color, Just waiting for my 110hv to come back from Castle...I'm gonna try it with a Feigao 9L with 6s 4500 and a 645 and see what gives.....

[Eyekandyboats]

Looks good.
nice.

Now on to you setup.
did i read that right ? 9L on 6S with a 645?
that is the recipe for a charr'd boat for sure
a 9L would run from 2-4S on MAX a 637 prop or a 640 is you have a very loose running boat
6S on that motor would pooch it for sure, and a 645 would pooch it even faster.

Personally i would run 6S on a 12-14 XL can with a 437 to start then go up.
Or you could run the 9L on a 4S setup with a 432 prop to start.

[RCprince]

I ran the stock on 6s, I was thinking really on 12XL on 10s...I have a 632 But it's a 1/8th hub

[RCprince]

Why most people run the 4 series octura and not the 6?

[Jeepers]

Why are you using that much battery in a BlackJack? 4s would be more than enough for a 30inch hull, cheaper and lighter too!

[RCprince]

I only have 5's and 6's in lipo's iand in nimhs I have 9 and 10 cell pairs...The BJ can handle it, I've done 51 plus already on a 6's with the tabs I think I can keep the hull in water...Just a lil fun R&D while I decide on my next hull which is either a hpr 115 or a christo time to move up I like those Big hulls

[treystoys]

I think what jeepers is getting at is that the lower voltage set up with the right prop has the potential to be faster because of the weight. I need to get mine back in the water with the gps to see if I can prove my point...lol...with the 6s set up, I'd start with an x438 and do an out and back pass then check the heat to try and avoid having to send your esc "back" in for repairs.

Good luck

Trey

[RCprince]

Why most people recommend the 4 series props and not the 6 series props

[Eyekandyboats]

who is "most people"?
a prop is a prop, people recommenced props suited to a boat.

[RCprince]

What I meant is oft times you'd get a 4 series rec over a 6 series like 4 to 1...Just wondered why....I would think since the 6 series has a smaller diameter it would have a less paddle effect plus more pitch....which is or are the Ideal prop series for cats...do you want the stern to lift out the water or the bow?

[Eyekandyboats]

the 6 series props can have what ever diameter you would like, Not alwayse a Smaller diameter, Paddle effect ? I don't know what you mean by that.
Yes the 6 series has more pitch then the 4 series counter part, it will run your boat more aggressive so it is possible to raise temps and amps. possibly why people recommend other wise ?

X series props are not lifting props

and for cats having the bow lift or drop is your choice. what ever works with your boat. There are to many to give you a straight up answer. Thats like saying " what has more horse power a GMC or ford. well lets see, there is over 60 models present and past."
you must be more specific. " what has more Hp a GMC Sonoma or a ford ranger

[Flying Scotsman]

Looks good.
nice.

Now on to you setup.
did i read that right ? 9L on 6S with a 645?
that is the recipe for a charr'd boat for sure
a 9L would run from 2-4S on MAX a 637 prop or a 640 is you have a very loose running boat
6S on that motor would pooch it for sure, and a 645 would pooch it even faster.

Personally i would run 6S on a 12-14 XL can with a 437 to start then go up.
Or you could run the 9L on a 4S setup with a 432 prop to start.

That is great advise, you are running a way too hot a setup and it is no wonder you blew an esc

Douggie

[RCprince]

advice taken

[obrien]

my bj with the ammo 2300 and trinity 4200 6 cell packs has run a best of 44.7 running a M440 prop. I have tried a few different props so far, and this one has been the best. I need to work on my 642 a bit more to see what it will do.

[RCprince]

This is the final hull mod...Still waiting for my 110 hv from castle....hopefully by christmas eve. I'm gonna run a feigao 9l and 5's 4500 with a 637...here are the pics

[Steven Vaccaro]

5s, 9L and x637 could/will either blow a esc or motor.

[RCprince]

why is that STeve? I ran the the ammo 2600 on 6's no issues with a 645..I thought I'd try the Feigao 9l because is has a slightly larger can with a smaller prop, how about a 632

[Darin Jordan]

That motor on 6S is going to turn at least 57,720RPM at the nominal voltage... fully charged, we're talking about 65,520RPM... That's NUTs, and isn't going to live long at all... It's going to pull MASSIVE amps... and even if you are running a Neu motor, which is rated at a max of 60,000 RPM, you're going to be KILLING motors off regularly... I find it rather hard to believe that you were able to run the 2600KV Ammo on 6S and it survived... the 2300KV version is what we use for 4S and it has to be VERY water cooled to do it... Are you SURE you are running 6S??? (22.2V Nominal??)

A proper 4S setup in a 30" hull should easily be capable of running into the upper 50's in OVAL trim... The RPMs you are turning are on the extreme even for a pure SAW setup...

If you want to run 6S, then you need to select the proper motor that will get your RPMs right... Target 30,000-35,000RPM for a boat like this... You need something in the 1600KV range to get it right... A 10XL or 11XL would really do the trick and let you turn a really decent sized prop... Would also be MUCH easier on the ESC... and would give you the right RPM for the application... ( the 10XL would be around 37,000RPM @nominal)...

I would think that either of those on 6S should be capable of 50's... without destroying any equipment...

Just my 0.02cents...

[RCprince]

Just a lil final touches..lol yea right

[RCprince]

Your 0.02 cents is worth a lot of dollars in my book....thanx for the rundown..but yea I did run a few times an ammo 2600 on 6's after fully charged, thats how I got the 52 mph before it went airborne. Well I'll try it on the 4's..what prop do you think I should run with the 9l on 4's...Thanx

[Darin Jordan]

On 4S, you are still looking at around 43,696RPM... figuring 4V/cell loaded (might be more like 3.9V/cell... so maybe closer to 42,120RPM...)... Personally, I'd opt for something with a lower KV for this application... even for Oval racing.... Something in the 2300KV range preferably... and that may be considered "hot" on 4S by some standards...

Your 9L is doable, though still "rigger" RPM range... You'll need to keep the prop small.... I would think an X637 might be an OK place to start... You may end up at an X438... I'm not really a prop expert when it comes to giving this type of advice... I would think Jay Turner or someone with his intimate knowledge of Cats would be a better source for a recommendation...

If it were me... I'd start with an X438, or maybe an ABC 42x55, or maybe the Grim 36x55 (same pitch as the 42x55, but smaller in diameter...)... and go from there... I think there are some prop-calc tools somewhere here that one can use to get a closer recommendation...

I run a Neu Motor of about that KV (2700KV) in my 26" DH Mono on 3S2P using an ABC 42x55 at around 32,000RPM and the boat heat races all day in the mid-40's... I think it'll go into the 50's in the straights if I put more prop on it... Temps are great, boat is light... batteries are MUCH CHEAPER.... ;) I don't even think I needed the 2P part, but I do it because the hull needs the weight and it's easier on the cells... Of course, the Nue is a more efficient motor with more torque, so it's not a one-to-one comparison KV wise... You'll likely be better off with 4S on that 9L...

I hope this helps some... I just want you to have as much FUN as possible, and as few "crispy pieces" as we can manage! ;)

[Steven Vaccaro]

Exactly how long of a runtime did you do with a 6s and the 2600? From the sounds of how you described the run, it sounds like less than 10 seconds or so. If thats the case, thats the reason you didnt see any problems for heat build up.

[RCprince]

Correct Steve, we would just do about 300 - 500 feet hole shots, wait a few seconds then go at it again

[Darin Jordan]

... Just went an looked... I would think a 10L (~2400KV) or maybe even an 12L (2040KV) would be a much more efficient setup... 12L would give you around 32,000RPM and should run for a long time, draw lower amps, and be very easy on equipment... Should also be capable of some pretty fast speeds... I guess it'll depend on what you are after... for all-out Oval racing, I'd have choosen the 10L I think... but again, I'd defer to Jay Turner or someone with his experience...

[RCprince]

Darin since I got back into Rc's in april- may..I have lol torched no lie let me see

1 CC griffin 55 -74.00

3 Electrifly's 35amps 120.00

Now Brushless

5 Suppomodel esc's ranging from 60 amps -100amps 29.00 to 44.00

3 e-flite 60amp pro switch. 74.00 ea

proboat BJ esc ?

Hacker 70 amp xpro 119.00

Align 75 amp 90.00

I could have bought a jeti spin 200amp by now.....I look at it this way I could be doing drugs, alcohol or chasing women...But I indulge my self in Rc Boats....

[Darin Jordan]

I could have bought a jeti spin 200amp by now.....I look at it this way I could be doing drugs, alcohol or chasing women...But I indulge my self in Rc Boats....


Yah... it works that way sometimes.... but we'll get you pointing in the right direction... ;)

Since you already have the 110HV coming... I wonder if maybe you could just get yourself a different motor and go ahead and run the 6S??? You'd pull lower amps than on 4S with the right motor... maybe a 11XL on 6S1P... which would give your around 34,000RPM... Since you already have the cells, and apparently have already purchased the ESC... this would just cost you another $70.00 for the motor... Same "power potential" as a 3S2P setup, but fewer amps... I think the higher V, less Amps setups are also more efficient, so it should run pretty cool, and would turn a healthy wheel...

All kinds of options really...

[RCprince]

Yea my replacement 110 is coming, mine stop working, just the light comes on and it links with the cc link but no motor tones...so they're sending me a replacement....Yea I'm gonna look into one of those XL's of a KB the KB might be a lil to heavy though....

[Darin Jordan]

I just saw this 8XL on RRR that you might want to look at... That'd work well on 4S...

http://www.rumrunnerracing.com/feforums/showthread.php?t=24356

[RCprince]

Cool thanx

[obrien]

Sorry to jump in here. I am running the ammo 36-50-2300 right now on 12 cells. If I was to go to try a 7xl which is a 2384kv I think, I should be able to pull a larger propeller since the motor should have a bit more tq.



RCprince, the boat looks great by the way. Lets see how close to 60 you can get her.

[Jeepers]

a X438 works pretty decent on a 7xl with 4s power. ( in a hydro)

[Diegoboy]

Mr. Prince, You have a PM. I have suddenly :cursing: come into a NEED for just such a hatch :swear:

[RCprince]

I made my hatch Deigo from a mold of a jolly hatch

[steveo]

dude that boats 100% better why didnt proboat do that in the first place

[RCprince]

Thanx Steveo...I'm resting the BJ for now...I'm working on my outboard Super Vee now Time to put it ack in the water...Just those darn ep1 gears...grrrrr