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View Full Version : BJ29 Pilots, what is your setup to avoid the bouncing?



dre414
12-12-2012, 02:06 PM
Im running a stock BJ 29 with a sharpened and balanced stock prop on 2S and cannot seem to get the bouncing (porpoising) to stop.

I started with the Prop strut flat to the bottom of the boat (placed boat on a flat surface and adjusted the strut so it was also flat on the surface) and the batteries at the front edge of the trays.

The closest setup I have gotten is with the batteries pushed all the way up on the the tray (almost falling off) and the prop strut really high such that the prop is almost touching the bracket. Although the bouncing has reduced some (however still bounces) the rooster tail is very high and it seems the prop is half submerged in the water. This can't be the right setup.

I looked around on the MG forums but I didn't get a clear answer besides having to buy an offset rudder or buying a faster drive system. Any help or tips would be greatly appreciated!

BTW I'm usually running on a very calm lake with the occasional 5mph wind on one direction.

MAMBA2200
12-12-2012, 02:16 PM
These hulls are good at bouncing you will find that a cat hull will be smooth then bounce and then smooth out again once you get fast enough. What i have done to calm mine down is set the strut about 1mm above level and angle it down about 1mm. But what you must take into consideration is that no matter how hard they try every hull is different so it will be different for every boat out there on setup. So try to use my setup and see if it works for you it might it might not but it is a starting point. Hope this helps you:beerchug:

CHIEFY_44
12-12-2012, 04:51 PM
I agree with mamba2200, every hull can be sorted in different ways, but the most important is making sure you dont have any concavement on the ride pads, these act like suction cups, what I did was blueprint the hull, taking all the concavement out of the pads and making them level with each other, then I made all the edges and things sharp and 90degrees. This helped a lot on my gieco, hope this helps, you can see step by step instructions by Darin Jordan in the miss gieco thread,

tlandauer
12-13-2012, 02:21 AM
I agree with mamba2200, every hull can be sorted in different ways, but the most important is making sure you dont have any concavement on the ride pads, these act like suction cups, what I did was blueprint the hull, taking all the concavement out of the pads and making them level with each other, then I made all the edges and things sharp and 90degrees. This helped a lot on my gieco, hope this helps, you can see step by step instructions by Darin Jordan in the miss gieco thread,
:iagree: My MG had a bounce that just would not go away until I blue printed the riding pads. It really makes that much of a difference, at least with mine.

mtbenjamin77
12-13-2012, 03:16 AM
:iagree: My MG had a bounce that just would not go away until I blue printed the riding pads. It really makes that much of a difference, at least with mine.

Yeah mine has a pretty bad hook in one of the sponson, it's not flat. That can create a bad bounce. I've found if you add lift at the transom the bounce tends to settle. set your strut at nuetral like you had it and score a line on the strut at the top of the bracket. this will give you a mark for reference. if you find a adjust ment that lessens the hop mark it. I'd say try lowering the strut to about 1.5mm below neutral keeping the strut flat. also try different props or add a slight cup to the one you have 1.2" to 1.7 cup. this will also improve your top end.

dre414
12-13-2012, 11:56 AM
Thanks guys for the good advice! the Darin Jordan thread was excellent information.. whereas I’ll probably blueprint and true the sponsons, It appears I have some more adjustment and trial and error to get the bouncing out regardless.. Mamba your advice got me really close so far (not too much time to test). I’m embarrassed to say that I didn't even know you can angle the prop as well as raise/lower the strut.. that just added about a thousand more combinations to try out..

What is good news is that having the strut all the way up such that the prop almost touches the bracket is ok.. I may have to grind the bracket a bit but at least it’s been done before.

Thanks guys I didn't think there was much to be done by way of tweaking a boat but after this thread there's tons to try and tons to still learn!

bob_t
12-13-2012, 11:31 PM
On my bone stock , other than PB SS prop, MG29 V1, (same hull) I found that the further fwd I moved the batteries, the "bounce frequency" (# of bounces per second, as I will call it for lack of a better term) got shorter and shorter, with more or less same bounce height, or amplitude, but never settled and ran "flat". For my particular hull (I know each is a "little different") it wants to ride "bow high" ... not excessive, but not flat like what you typicallysee/expect for cats. So, I started moving my batteries back, and the "bounce frequency" got longer between bounces, and now, althought it rides slightly more "bow high" than I would like, it doesn't bounce. The boat seemed like it was trying to carry the bow, but it would "drop" due the batteries (really, the COG) being too far fwd, then it would lift the bow again, would try to carry itself, drop again, and keep repeating this cycle. Strut is set with centerline even to slightly ~ 1/32 - 1/16 above rear ride pad. I'm using a PB SS prop that has been balanced, blade matched and slightly sharpened .... which brings up another point ... my friend had a brand new Mystic - it comes stock with the PB SS prop, but they are not balanced! His was so far out of balance that it rather quickly destroyed the aft most bushing in the strut due to vibration. It was significantly out of balance ... the hub was not drilled straight! With a lot of work, it is now static balanced (he has since then also bought a new one, and that one wasn't too bad - it was drilled straight and is now balanced extremely well). Not saying that my setup is ideal, as I would love to see it run fast and "flat" (someday it will probably have an unfortunate "blow-over" event), but it seems to perform well in the wind protected ponds where I run it.

dre414
12-14-2012, 07:03 AM
Thanks Bob agree with the frequency based on the battery location.. I found the same thing when I moved them al the way up.. faster bounce but not as high. Although not static balanced I did balance and shapen the stock prop. I howevr never looked at the shaft bore being straight. I have a few extra batteries coming in today and I pulled out my calipers so this weekend (wife's honeydo list permitting) Ill be doing some methodical testing.

I took a quick look at the hull and although my right sponson is nice and flat the left sponson is somewhat cupped and tapered towards the center of the tunnel. I plan to bluprint and flatten but not till I get it smoothed out as much as I can.

ray schrauwen
12-14-2012, 02:51 PM
I find the combination of blueprinting sponsons, homemade offset and extra weight settled mine down very nicely. Too much weight and the motor will burn up though!

dre414
12-17-2012, 11:28 AM
Update, I tried every variant I could get and still come back to the setup I described in my OP. Prop almost touching the rudder bracket and the batteries all the way forward falling off the tray.

Bob, I got it to settle w/ the batts back far however the bow rides way too high and almost blows over at speed (esp. upwind), IMO I'd rather have the higher frequency bouncing instead... thanks for confirming the behavior!

Ray when you say extra weight.. what did you use? where and how much? I was thinking about using fishing weights to see if that would balance things out further but ran out of batteries and daylight yesterday.. if it worked, I would switch out to those self sticking airplane weights..

I'm sure blueprinting is required but I'm hoping to get as close as possible to balanced before I go there.

Thanks!

dre414
12-23-2012, 12:23 PM
Guys so I finally dialed it in without bluebrinting.. I set the prop to the best I could get it on 4S and then popped in 5s for the first time.. boy did it run fast! and it settled down allot!! Seems that the added weight and power balanced out the bouncing effect.

I ran it for a few laps around the lake on 5s and no temp propblems.. I took it back out and unfortunatly I made the mistake of trying to reverse out of a tight spot of grass and POP there goes the motor!! Why I didn't program the ESC to remove the reverse and why I tried to reverse out is beyond me!!

So now that I have an opportunity to buy another motor (ESC seems to be working still) I was hoping for some suggestions. I really liked the 5s speed.. can you either confirm or recommend a solid 5s motor? I was thinking about either the old version of the PB 1500Kv or a OSE leopard 3650 1600Kv.. I'm using the stock ESC (80 amp Dynamite) and stock prop and am willing to get another prop if you can advise the best motor/prop combo. Thanks in advance.. can't wait to get this baby back on the water. Looks like now Ill have time to finally blueprint it..

ray schrauwen
12-23-2012, 01:26 PM
I find the combination of blueprinting sponsons, homemade offset and extra weight settled mine down very nicely. Too much weight and the motor will burn up though!

Imagine that adding weight settled it down, hmmm....

bob_t
12-23-2012, 04:20 PM
dre414, where did you have the batteries positioned, fwd or centered or back, in their trays? I have a spare (new) 60A PB esc (part number PB4018, parts list part number for the Mystic) and the package says "with reverse" ???? Programming card for those controllers doesn't have a setting for turning reverse "off". Does the dynamite 80A programming card have that option? Would love to know how to disable reverse on the one I have, if anyone knows, as a side note.

dre414
12-23-2012, 04:52 PM
Imagine that adding weight settled it down, hmmm....

Thanks Ray, I tried some additional weight using wheight strips on 4s and still had bouncing.. I feel the additonal power helped as well. Any suggestions on the replacement motor??

Doby
12-23-2012, 04:59 PM
I find the combination of blueprinting sponsons, homemade offset and extra weight settled mine down very nicely. Too much weight and the motor will burn up though!

Just buy an AQ Motley Crew!

dre414
12-23-2012, 05:03 PM
dre414, where did you have the batteries positioned, fwd or centered or back, in their trays? I have a spare (new) 60A PB esc (part number PB4018, parts list part number for the Mystic) and the package says "with reverse" ???? Programming card for those controllers doesn't have a setting for turning reverse "off". Does the dynamite 80A programming card have that option? Would love to know how to disable reverse on the one I have, if anyone knows, as a side note.

I had them pushed forward almost half way off the tray and angled in so that the half of the battery that was off the tray was resting on the center deck. Prop strut was set high (within a quarter inch of touching the bracket) and angled flat. As for the ESC, I may be wrong but the programming card (DYNM3821) has a reverse setting.. the instructions indicate this is to turn off/on the reverse.. again, I never tried it (now wish I did and forgot to set it back) but I assume thats what it's for? Unless it's to reverse the motor direction? If that's so then it's redundant seeing as you can just swap a couple of motore leads.. Don't know about the ESC you have, sorry.

tlandauer
12-23-2012, 05:36 PM
I had tried to move the batteries as forward as possible and another stick of Nimh in front of the motor as dead weight, NO USE! Then I thought it was time to blue print and true the pads---something I was trying to avoid all along.
Well, it helped a great deal and I wish I had done it sooner. There is a seemingly threshold relationship between bounce and No bounce. On mine ( 4s2p, m445, Leopard 4082, 2200kv) .
Once I am in the last 20% of throttle, the bounce decreases, but below mid to above mid throttle it will bounce. ( this before truing the pads)
If you true your pads I believe you will see improvement, this comes from a one time non-believer.

scrillamil
01-06-2013, 06:41 PM
Dre did you sort your bounce out? When we are running (2) 2s 5000mah 60c was no problem but as soon as I jumped to (2) 3s 5000 30c it really woke up but tryin to keep in the water w/o flipping is my issue :rockon2:

dre414
01-07-2013, 12:25 PM
Hey Guys, sorry its been a while.. Happy New Year!

Over the holidays I replaced my blown stock motor with a Leopard3674 1900Kv and while I was at it, I decided to upgrade the ECS to a SeaKing 180 ESC V3 (extra caps) just to be safe. While waiting for the parts, I got around to blueprinting the sponsons.

Man was that allot of work squaring and sanding, I never realized how quick filler sets.. Anyhow, to my surprise it came out pretty well, all surfaces are square and very flat.. I however wish I had done a better job of painting.. the clear coat seems to stick to the foam on my boat stand even after a few days of drying upside-down. As of now I have lightly sanded the sponsons, partly b/c I can’t stand the smudged finish and partly b/c my LHS guy told me that lightly sanding the finish will create turbulent flow and stop and sticking to the bottom. Anyhow below are pics of my work.. I noticed a small crack near the prop tube so I filled and painted a bit there as well.

This weekend I ran the new motor and ESC setup on both 4s and 5s with the stock 1.6x2.5” (~ X640) prop in the morning and then in the afternoon with some more wind and it ran great in both conditions! No heat on the motor, esc, whatsoever even on 5s. It feels like 6s will be no problem (although I probably won’t bother).

The handling was much improved with a tighter turning radius and very crisp cornering (no sliding on the surface). It spills lots of speed on the turns but is very fast on the straights. Most importantly, although not gone completely, the height of the bouncing (amplitude) was dramatically reduced and the frequency was also considerably less such that I don’t notice it as much. On glass water, it’s still there but much less frequent and not as choppy. In slight ripples and upwind, the air gets under the hull a bit more and kills the bouncing altogether. Blueprinting does help! LOL.. During my last 5 s run the wind picked up and I got her in the air.. luckily for me she got enough air to backflip completely and land right side up.. drove her back, looked her over and back out she was (slower on the throttle in that direction however).

In all runs, I still had the prop strut set as high up (to the waterline) as I can without touching prop to strut bracket. The prop angle was slightly pointing down. Both batteries were far up on the tray and angled in pretty much resting on the center of the hull and touching the Styrofoam block.

I bought a few more props of varying sizes (time to perfect my sharpening/balancing skills) to see how they affect speed and bouncing. I should probably get some GPS telemetry for speed measurements. I’ll keep you posted..

91360

91361

91362

91363

CHIEFY_44
01-07-2013, 01:53 PM
Dre414 I suggest you try a octura m445 prop that's what I have found to work best for me, I also trimmed the bracket of the strut for more clearance. With basically the same setup except I use a Leo 4074 2200kv with 4s2p it rides great, I agree the faster the boat runs the less bounce you get the magic figure seems to be 50mph at this it just flattens out and runs awesome

scrillamil
01-07-2013, 06:35 PM
Nice work👍 looks good. Going to repair my old hull and work on blue printing. Awesome input

dre414
01-08-2013, 07:24 AM
Dre414 I suggest you try a octura m445 prop that's what I have found to work best for me, I also trimmed the bracket of the strut for more clearance. With basically the same setup except I use a Leo 4074 2200kv with 4s2p it rides great, I agree the faster the boat runs the less bounce you get the magic figure seems to be 50mph at this it just flattens out and runs awesome

Thanks Chiefy, question on the motor.. I was considering the 4074 but wasn't sure if it would fit.. may I ask what the difference is b/t 3674 and 4074 besides the size of the can? Does it have more torque? I was also considering 2200Kv however wasn't sure if that would be reliable on 5s.. Ill try the M445 or sure.

Oh yeah I forgot to mention, I noticed the tips of my prop after a few runs were dull and almost rounded out.. I was thinking the prop tips squeezing all that incompressable water between tip and the bracket would do a number on the prop tip. Cutting the bracket will be my next modification.

CHIEFY_44
01-15-2013, 12:32 PM
Sorry about the delayed reply dre, but I work at a hobby store and its been hectic, not really sure of the difference between the motors, but I really don't run anymore than 4s voltage in any of my boats, my rigs are quick enough in this configuration and reliable that's what I want for racing, to win you have to finish. I just do a lot of testing and tweaking of my rigs to get the best out of them, not just slap 5 or 6 cells in and hope the electronics survive I have gd temps when I setup for 7 laps and 20-30% left in the cells.

dre414
01-16-2013, 02:41 PM
Sorry double post.. this one was deleted.

dre414
01-16-2013, 02:42 PM
Thanks Chiefy, I managed to get allot of time this past weekend to sharpen/detounge some props and try them out on the water. I tried a X642 and an M445 both in 4 and 5s configurations.. I have concluded that my favorite prop is the M445. After running the M445 it feels/sounds like the stock 640 and 642 props are churning allot more water than pushing it. With the 445 it sounds quieter and the boat has allot of acceleration. The problem is that at full throttle on the M445, the boat gets too much air and flips out of the water... I had a pretty bad crash that ended up with a shattered canopy; thank God I had a spare and it was close enough to shore to recover the boat. Overall the motor I have works really nice and reliably, so the motor can size to me is not a non-issue.

Regarding the 4s and 5s debate, from the posts on here this is quite a hot topic. Whereas the insane speed of 5s was cool it was a concern to be sure not to flicp back or overheat. I noticed one of my battery connectors kept disconnecting and had arc burns.. don’t know if it was a loose connector or the amount of current passing through it but the little exposure I had to this made it apparent 5s is not as reliable. Temperatures were not an issue.. but as you said, the key is to finish (or in my case not get stuck out in the center of the lake). So whereas I think this setup could run 5s all day (with a better connector), I’m sold that a high performing reliable 4s setup is golden..

Back to the original post topic.. the bouncing was still there but still nowhere near as much and as frequent as before blueprinting the sponsons and upgrading the ESC/Motor/Prop.. still more bounce on glass water than ripples and more bounce on 4s than 5s (probably the weight) but nominal. I don’t know if it will ever be gone altogether at all throttle ranges.. There is however a sweet spot in the throttle range that does't have any bounce at all but I know there is more juice left.. so hard to not go too fast when you know it will go much faster.

More of the questions…

1. Are you able to run your setup (4s M445) at full throttle? If so do you have additional weight besides the battery or should I just calm the heck down and expect to not give it full throttle till the batteries have died down some?
2. With the couple of nasty crashes I had, one of my battery trays came loose.. I read on here that many boaters just pull the trays off and Velcro their batteries to the sponson deck. Would anyone recommend the same for a MG/BJ29? Do you think this will further dial out the bounce?

CHIEFY_44
01-16-2013, 05:13 PM
DRE WATCH THIS VIDEO AND I'LL POST THE SET UP LATER
http://youtu.be/rexRB9LXKEw

CHIEFY_44
01-16-2013, 05:15 PM
I can run at full throttle and never let off unless it looks like flipping, no additional weight just set cog at 33% and I'm golden.
As to trays mine came loose and I re glued them in at a angle to ease battery installation, another thing I did was fill the front part of sponsons upto about 1-2 inches from the canopy opening, this help stop the hull splitting in a bad flip, then I strengthen the seams with extra fibreglass, remove water outlet and move to top deck that's all the mods I have done. I have a video on you tube if your intereste

olwarbirds
01-16-2013, 05:16 PM
My buddy and I finally did the motor and esc swap.... leopard 4082 2000kv 180 amp seaking xtra caps...stock prop on 6S it screams ... added onto the battery trays and moved the 2 11.1v 5000mah 65c lipos forward...the back of the lipos is now where the front would of been in the stock location....no bounce probs at all...cant wait to try a better prop...will get vid up when I get the chance... DJ

dre414
01-17-2013, 11:13 AM
DRE WATCH THIS VIDEO AND I'LL POST THE SET UP LATER
http://youtu.be/rexRB9LXKEw

Ok my boat is nowhere near that smooth and stable at full throttle.. I definitely need some more tweaking.

dre414
01-17-2013, 11:20 AM
I can run at full throttle and never let off unless it looks like flipping, no additional weight just set cog at 33% and I'm golden.
As to trays mine came loose and I re glued them in at a angle to ease battery installation, another thing I did was fill the front part of sponsons upto about 1-2 inches from the canopy opening, this help stop the hull splitting in a bad flip, then I strengthen the seams with extra fibreglass, remove water outlet and move to top deck that's all the mods I have done. I have a video on you tube if your intereste

Thanks and after seeing your video I know I don't have it dialed in.. I thought I did but there is clearly room for improvement. When you say you filled in the sponsons.. are you talking about the 2 part expanding foam they sell on OSE? Also you said about 1-2 inches from the canopy opening I take it you mean 1-2 inches short of touching the original battery tray locations? Would you say the additional wieght of the foam is what helps?

CHIEFY_44
01-17-2013, 12:37 PM
I didn't add weight at all, and yes I mean the 2 part foam from ose, and I mean fill sponsons with it so that the foam finishes 2inches from the hatch opening or so you can get at the water outlet if you move that, basically I covered the Styrofoam that is in there already. I have also tucked the rudder blade towards the hull doing this seems to pull the front down, you could try that.

scrillamil
01-17-2013, 05:54 PM
I was wondering same thing😉 Chiefy boat runs great that's exactly what I'm hoping for just want to reduce the hopping on mine.

dre414
01-17-2013, 07:18 PM
Thanks again Chiefy. I looked around, i guess 2part polyurethane closed cell light density is what I should be looking for. Looks like scary stuff to work with but what's the worst that can happen right? I think I'll move the battery trays, try the rudder and mess with weight distribution a little more before I play with the foamy stuff.

I'll keep you all posted.

lenny
02-25-2013, 06:16 PM
Good to see it is running smooth for you now.:tiphat:
So how did you go about getting the rudder to tuck in ?
And also what size cells are you running in the video ?


I think when you added the foam to the sponsons that also added some dead weight to the bow.



I didn't add weight at all, and yes I mean the 2 part foam from ose, and I mean fill sponsons with it so that the foam finishes 2inches from the hatch opening or so you can get at the water outlet if you move that, basically I covered the Styrofoam that is in there already. I have also tucked the rudder blade towards the hull doing this seems to pull the front down, you could try that.

CHIEFY_44
02-27-2013, 12:32 AM
This is the setup in that video.
T-180
Leo 4074
M445 prop
4s2p 4000 maho
Strut level with sponsons and no angle
Rudder tuck in towards rear of hull.
Ok Lenny how I tucked the rudder was I replace the bottom bolt in the blade with a smaller one, actually its a plastic/nylon shear bolt now and when I did this it allowed the blabe to be tucked in towards the hull, why doing this helps I don't know why, but it does.

lenny
02-27-2013, 07:45 AM
Hey, :tiphat:

Thanks for the info on the rudder.

The rudder most be a better setup than the Mystic rudder now,

With the new brake away bolt.

Could someone post some good pictures of the transom and all the hardware please,:tongue_smilie:

I did a search for pictures, But nothing any good showed up.

AlanD
03-08-2013, 06:04 AM
Olwarbirds, how did you add on to the battery trays? It sounds like you have the same Thunder Power 5000mah/65C/3S packs I'm using. My new BJ29 is 100% stock but my first run showed some minor signs of bouncing when I gave about 80% throttle. I'm curious what your mods look like. If you can share some photos, that'd be great.

For what its worth my sponsons are 100% flat and dont need any blueprinting. With Dre's pointers, I placed the battery packs 50% hanging over the front edge of the tray with the leading edges of the batteries on the hull center.

olwarbirds
03-08-2013, 05:17 PM
Alan, I just bought a new digicam today :) ... we will be posting pics and more vids very soon... We are no longer running the stock setup.. We are now running the leopard 4082 2000kv with the 180amp esc and upgraded flexshaft all from OSE...I from now on will be using Dinogy lipos..for the price YOU cant beat the quality or the warranty ! ..... we just moved are battery trays forward ...the new setup is stupid fast... DJ

Barrel Roll Joe
03-08-2013, 11:53 PM
94958949599496094961

Not sure if these will help. I was able to tuck my rudder as much as it would go without having the pushrod touch the bracket. Just loosened stock bolts adjusted rudder then tightened, seems secure.

lenny
03-09-2013, 12:47 AM
Thank you.:tiphat:
How is yours running for you ?
And is that stock setup in it ?

Barrel Roll Joe
03-09-2013, 01:47 AM
Runs good, only have ran it four times so far and its pretty much stock except for the prop and shaft. trying to work out the bounce as well. gonna try and make this boat a monster and by the looks of the videos im gonna need to do my homework when it comes to choosing the right motor. 4074 or 4082 seems to be the question?

olwarbirds
03-09-2013, 05:48 PM
leopard 4082 1800-2000kv for 6s...2000-2200kv for 4s....we did not have to tuck the rudder to take out the bounce...are BJ29 runs extremely smooth...(no bounce) with the 2 3s lipos moved forward...

lenny
03-09-2013, 06:09 PM
Hi,
Where is the boat strut set at ?
And do you have any pictures of the setup with cells in place for no bounce ?
Also any video's of it running ?

olwarbirds
03-11-2013, 05:52 PM
Hi,
Where is the boat strut set at ?
And do you have any pictures of the setup with cells in place for no bounce ?
Also any video's of it running ?

Hi Lenny.... strut is even with the transom no pitch....lipos (2 3S) back of batteries are even with motor mount, so they are way forward of stock mounting position...sorry no pics yet..got new digicam but with workn two jobs NO TIME to play...in both vids the BJ29 is still being run on the stock motor and esc, using 2 3S 40C lipos....we are now running a leopard 4082 2000kv 180amp seaking with cap bank and 2 3S 65C lipos...I will try to get new vids soon .... DJ

http://www.youtube.com/watch?v=6A7MWH_l_aE

http://www.youtube.com/watch?v=RZQmYMmJ3Sc

Barrel Roll Joe
03-14-2013, 01:53 PM
hey warbird...you have that leopard wired with 5.5 bullets? if so is it wired exactly like the stock setup? about to order that esc motor combo you have just wondering if i should replace connectors with bullets.
Hi Lenny.... strut is even with the transom no pitch....lipos (2 3S) back of batteries are even with motor mount, so they are way forward of stock mounting position...sorry no pics yet..got new digicam but with workn two jobs NO TIME to play...in both vids the BJ29 is still being run on the stock motor and esc, using 2 3S 40C lipos....we are now running a leopard 4082 2000kv 180amp seaking with cap bank and 2 3S 65C lipos...I will try to get new vids soon .... DJ

http://www.youtube.com/watch?v=6A7MWH_l_aE

http://www.youtube.com/watch?v=RZQmYMmJ3Sc

lenny
03-14-2013, 04:19 PM
Put 5.5 on everything,
What s cells are you thinking of running with the setup ?
And on what kv motor ?


hey warbird...you have that leopard wired with 5.5 bullets? if so is it wired exactly like the stock setup? about to order that esc motor combo you have just wondering if i should replace connectors with bullets.

Barrel Roll Joe
03-14-2013, 06:11 PM
180amp seaking with cap bank, leopard 4082 2000kv on 6s. just wondering i guess i have to make a jumper wire with 5.5 bullets to link the batts together?

lenny
03-14-2013, 06:31 PM
That kv is very high for 6s,
You will be stressing that setup if you do not run a small prop.
And then it still will be pushing very high rpm 44.400 on the bearings of the motor and maxing out the esc to.
Is it just going to be used for saw runs ?

Barrel Roll Joe
03-14-2013, 09:16 PM
Isn't this the setup olwarbirds is suggesting? Just looking to make it fassssst as possible on 6s. I saw on YouTube someone was using Leo 4074 1400 kv with the seaking 180 and it looked super fast. What would you suggest?

olwarbirds
03-15-2013, 06:56 PM
To clarify....the stock setup has impedance problems not the leopard setup....We are running a leopard 4082 2000KV with 180amp seaking with cap bank on 6S...with NO heat or meltdown problems at all....We do have separate cooling lines for the motor and esc.....I made up series connectors using ec5 connectors...I just personally dont like using straight bullets to hookup batteries..but thats a personal touch..each to their own madness...anytime Im using more than a 6S total setup I use xt60 connectors...something ive been doing since I became a EDF Jet junkie running high output (200amps + is very common)...seen a mishap with using just bullets to hook up lipos....(guy lost part of his hand, right next to me).....hope that clarifies the misunderstanding of what we are running... DJ

olwarbirds
03-15-2013, 07:06 PM
180amp seaking with cap bank, leopard 4082 2000kv on 6s. just wondering i guess i have to make a jumper wire with 5.5 bullets to link the batts together?

Joe, we used 10GA wire for our leopard setup...and yes 5.5 bullets would work....heads up its stupid fast....but the hull can handle it...just take the time to tune it right....its not that hard of a boat to get running smoothly...those vids I posted were runs 2 and 3 on the stock setup ....sorry for delay in responses...I work two jobs...one at VA hospital other at hobby shop so spare time is short...hope to run and get vids this weekend if the weather permits... DJ

Barrel Roll Joe
03-16-2013, 12:19 AM
DJ, thanks for the info I plan on running 5.5's on the motor wire and ec5 on battery connections. What prop are you finding works the best? Im looking to get some dinogy 3s batts. I have two venom 5000 35c to start off with.

olwarbirds
03-16-2013, 10:38 AM
Joe, be careful with those venom 35c lipos, that leopard 4082 2000kv is a amp hog, we have puffed a couple of the venom 40c...id use the stock prop with those venoms...we are planning on doing some test runs with diff props tomorrow (weather permitting)...We did split are cooling lines so that the motor and the esc had seperate water supplies...all we did was use a vacuum line splitters...eventually we are gonna use a rudder with dual water pickups...

Barrel Roll Joe
03-17-2013, 08:56 PM
Thanks for the heads up just ordered a couple of dinogy 65c. Did you have any luck testing props?

AlanD
03-18-2013, 07:08 AM
Olwarbirds, I made some battery pack supports out of Styrofoam so the trailing edges of the batteries are in line with the front end of the stock wood battery trays. This moved my COG forward by about 3 inches. I also lowered the prop strut 1/4 inch below neutral.

This made a HUGE improvement in eliminating the bouncing. I have a little bouncing when at 100% throttle and it runs fast considering everything else is stock. I think I'll be able to trim that out by playing with the strut angle.

I still want to see pics of your setup though.

jeffrey1
03-18-2013, 08:15 AM
what i did was lower shaft a little and made custom bett.trays works well.it will sometimes buck alitttle but not nearly as bad as stock.

olwarbirds
03-18-2013, 06:10 PM
Thanks for the heads up just ordered a couple of dinogy 65c. Did you have any luck testing props?

YW, yes we did try a couple of props out...to our surprise the one that gave the best bang for the buck was a cnc from OSE.. part# cnc-4514251 not bad considering its only 20$...we havnt tried any sharpened/balanced berylium copper props yet...had to many boats to test ... found out too late i had my digicam setup wrong and ran out of memory...but we did get a few saw runs in later in trout stream at home... will try to post those vids soon...DJ

olwarbirds
03-18-2013, 06:15 PM
We did the same thing for batt trays..made some out of styro...yes it does occassionally buck a little but you have to consider the speeds we are running on 6S..for the most it handles just fine for a cat with no hull or running hardware mods...just prop/motor/esc....had a great day on the water yesterday :) got to run several of my fleet, with new upgrades....ive got the FE sickness bad !!!! .... DJ

AlanD
03-18-2013, 08:26 PM
Since we're talking about the BJ29 on this thread, has anyone else had problems with water getting in the motor/battery area? I tape my hatch every time so its not that, and I taped over the drain plug thinking it may be leaking but I'm still getting a lot of water in that area. It's not the water outlet either because I put paper towels around it and against the transom. I can squeeze about a quarter cup of water from the transom.towel after a 6 minute fast run. My next step is to remove and silicon behind the strut bracket.

The starboard battery tray is sprayed with water yet the towel around the water outlet is dry. All water hoses have good seals and show no signs of leaks. I also put a rolled up paper towel under the stuffing box and its wet as expected, but can it be letting that much water in?

tlandauer
03-18-2013, 11:02 PM
Any leaks around the motor jacket? Do a test: disconnect the hose from the rudder, find yourself a syringe, pump water into the hose until you see water coming out of the outlet, now use your finger to block the outlet and continue to pump, you should feel pressure from the syringe and the outlet, when you release from the outlet, water should shoot out.
should also do a static test, load up with batteries and put boat in a tub or pool for several minutes and check for leaks. If your strut bracket attachment is leaking, you should be able to see water collecting near the transom. Also check if there is any tear on the rudder rod boot.
You said "SPRAY", the evidence of spraying is if the water is mixed with grease ( if you use those blue greases) and you see the mist of the mixture, then it ( water) is coming thru from your stuffing tube. Cut a very short piece of the same silicone hose and place it over the stuffing tube and between collet. 95522
I used another larger tube to "collar down" the silicone tube but if you have the right size , it is not needed.

olwarbirds
03-21-2013, 04:08 PM
I always do what tlandauer shows ....nicely done man... DJ

AlanD
03-22-2013, 07:17 AM
Its the little details that make the difference. Great idea tlandauer. I'll try that.

Olwarbirds, what was your motivation to upgrade your flexcable to the OSE cable?

olwarbirds
03-23-2013, 11:53 AM
Alan, the OSE cable is just better quality than the stock stuff.... DJ

hydro_pyro
03-23-2013, 07:44 PM
In the 1:1 world, performance outboard catamarans such as the Skater have this same porpoise tendency. We call it "clearing the bubble." Trim gives the driver some control over it. As the boat builds speed, the tunnel begins to pack air. The air lifts the bow somewhat, increasing the angle of attack and thus packing more air. As the tunnel compression lifts the rear, the bow drops and the air "burps" out the back, starting the cycle over again. Typically, the driver trims UP to keep the bow from dropping as he accelerates through the porpoise zone. Once the boat achieves a higher speed, there's enough air entering the tunnel to lift the entire hull including the stern, and the driver lowers the trim back to a near-neutral setting as the angle of attack flattens out on a bubble of flowing air.

In the case of our scaled-down catamarans:

This is why a rearward COG holds the bow high to reduce porpoise, but increases blowover risk at high speeds;

This is why hanging the batteries far forward reduces porpoise, it forces a flat ride and stops the tunnel from packing air altogether;

This is why a high strut setting reduces porpoise-- it reduces bow lift and increases stern lift.

With our electric boats, we can't overcome midrange porpoise with trim adjustment, so handling and speed are always somewhat of a compromise. The best solutions seem to involve circumventing the benefits of aerodynamic catamaran design, and trying to make the boat run more like a hydroplane. ;)

ray schrauwen
03-24-2013, 11:01 AM
Interesting...


In the 1:1 world, performance outboard catamarans such as the Skater have this same porpoise tendency. We call it "clearing the bubble." Trim gives the driver some control over it. As the boat builds speed, the tunnel begins to pack air. The air lifts the bow somewhat, increasing the angle of attack and thus packing more air. As the tunnel compression lifts the rear, the bow drops and the air "burps" out the back, starting the cycle over again. Typically, the driver trims UP to keep the bow from dropping as he accelerates through the porpoise zone. Once the boat achieves a higher speed, there's enough air entering the tunnel to lift the entire hull including the stern, and the driver lowers the trim back to a near-neutral setting as the angle of attack flattens out on a bubble of flowing air.

In the case of our scaled-down catamarans:

This is why a rearward COG holds the bow high to reduce porpoise, but increases blowover risk at high speeds;

This is why hanging the batteries far forward reduces porpoise, it forces a flat ride and stops the tunnel from packing air altogether;

This is why a high strut setting reduces porpoise-- it reduces bow lift and increases stern lift.

With our electric boats, we can't overcome midrange porpoise with trim adjustment, so handling and speed are always somewhat of a compromise. The best solutions seem to involve circumventing the benefits of aerodynamic catamaran design, and trying to make the boat run more like a hydroplane. ;)

olwarbirds
03-24-2013, 05:45 PM
Interesting stuff....yes we are giving up some handling for speed...running the BJ29 on our setup using 6S is more of a SAW running type setup as Lenny previously mentioned...2/3 throttle is max turning speed for sure and the water had better be smooth!...I cant tell you how many times the BJ has cartwheeled/flipped/barrelrolled/sumersaulted and any other none boat type manuevers you can imagine, but it has shown to be a very resilient hull...one thing I did want to point out was that we were not looking to race our BJ29, I have other cats for racing, our goal was to see what kind of topend speeds we could achieve before loosing all control...we are just insane like that :help:

If your going to use a mtr upgrade like the Leopard 4082 using the stock motor mount, you will need to add rear motor support or get the OSE mtr mount...the way I insure not having cooling line leaks is to use Dubro fuel line clips, their a very secure seal around nippled and smooth fittings, plus I use quality cooling/fuel line.

Barrel Roll Joe
03-26-2013, 12:27 PM
Any vids yet DJ?

hydro_pyro
03-28-2013, 04:41 PM
I got rid of nearly all the porpoising.

-Custom tuned factory prop... Thinned, tried, sharpened, balanced.
-Three 2s hard packs in series
-COG at 7.75" from the rear edge of the running surface.
-Strut top 1/4" above the mount. Prop tips have 2mm of clearance.

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/2E7771ED-84A3-4BE2-8C36-3B093E34E55E-3264-0000074FE36F6554.jpg

Stock boat and electronics. Tiny bit of hop with GPS in the boat. :D

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/C3AF47B4-FA3D-4B1F-AE28-ABC54896F81E-3264-000007493F5A83BA.jpg

hydro_pyro
03-28-2013, 08:08 PM
On smoother water this evening, I was not able to repeat those numbers, or the bounce-free ride. Only got 51 mph, with lots of hop. Almost blew over a few times. This boat LOVES a bit of windblown ripple-chop on the surface.

olwarbirds
03-29-2013, 05:32 PM
Any vids yet DJ?

No...its been snowing here in the NC mountains again...hopefully we will have something new to show soon... DJ

olwarbirds
03-29-2013, 05:40 PM
Thats the speeds we came up with for the stock setup on 6S was right around 60MPH...with the leopard setup we are in the 70MPH range.. sure looks good all sharpened and shined up ....yes on glass smooth water it does seem to like to hop more...

AlanD
03-31-2013, 03:28 PM
The good news: tlandaur, your silicon tube seal on the flexcable worked perfectly. I also removed and silicon-sealed the strut. Found some water leaks there. Not a drop of water in the motor or radio area now. Great pointer. Thanks.

The bad news: I fried the wiring going into the stock Dynamite3830 motor. Ran for 8 minutes on 6S/65C see saw runs. Minimal hopping and great speeds. Proboat says the motor is rated for 6S but that wiring is totally underrated for 6S.

I guess I'll be moving ahead with my leopard 4082 upgrade sooner than expected. Olwardbirds, what motor mount did you order from OSE for your Leopard upgrade?

96502965039650496505

hydro_pyro
03-31-2013, 05:03 PM
The electronics can handle 6s. However... Inconsistencies in the quality of the physical connections can be the weak link. I did numerous top end runs on 6s, and the only things I experienced we're a little bit of burnt smell from the motor (Horizon tells me this is normal, just breaking-in the winding enamel), and flinging all the grease out of the flex-shaft.

The failed motor connections aren't happening to everyone running 6s.

tlandauer
03-31-2013, 06:33 PM
The good news: tlandaur, your silicon tube seal on the flexcable worked perfectly. I also removed and silicon-sealed the strut. Found some water leaks there. Not a drop of water in the motor or radio area now. Great pointer. Thanks.

The bad news: I fried the wiring going into the stock Dynamite3830 motor. Ran for 8 minutes on 6S/65C see saw runs. Minimal hopping and great speeds. Proboat says the motor is rated for 6S but that wiring is totally underrated for 6S.

I guess I'll be moving ahead with my leopard 4082 upgrade sooner than expected. Olwardbirds, what motor mount did you order from OSE for your Leopard upgrade?

96502965039650496505
Good to hear the water issue is gone, 8 min. run is extremely long and on 6s it is not surprising for something to fail. Assuming that your run was continuous. The wiring and especially the plugs are always a joke to me, anyway.
For my curiosity: does the motor still turn or it is completely dead? I can see the insulation has suffered hight temp.

AlanD
04-02-2013, 05:54 AM
The motor turns as normal but won't run. It didnt get over 120F degrees on the previous runs. I'm returning it to Horizon Hobby today.

I'm keen on the leopard 4082/2000kv with a T180 upgrade only because other posters have had success from this setup. I will only ever be running 6S since that's what I've invested in battery wise, but I'm unclear on prop choice and expected run times. I know I need to prop down so can someone recommend a sharpened/balanced prop that I can use with my proposed setup that won't fry things, still give me crazy speeds, and allow me to run until LVC?

Most of my runs are 80% + on the throttle which I understand to be less of an amp strain. Am i expecting too much?

(These questions may seem noob like, but I'm coming from a nitro background and although I have a degree in light current electronics I'm perplexed by some of the rational I'm reading on this forum :) )

tlandauer
04-02-2013, 11:24 AM
HI Alan,
I understand your desire to upgrade and stay with 6s since that is what you already have. Keep in mind that the 4082/2000KV is really a 4s motor, I have a 4082/2200kv with a m445 prop and this motor is an amp hog, so I run 4s2p, with the parallel set up I have 10,000 mah and I get good run time. Yes, I can get over 6 or 7 min. continuous run time, but I always NEVER do that because of heat build up. After 2 min. I bring the boat back and check temp, then go out again. The heat build up can damage your gear, as heat builds up, the likelihood of failure grows disproportionally, and that is just talking about my set up with 4s.
If you have not bought your motor yet, I would look into the something in the 1600kv range . Are you using 6s2p? I doubt it will fit in the boat, if you plan to use two 3s, there will not be as much run time as you hope.
Also keep in mind that part throttle is HARDER on the equipment than running full throttle, I am not a nitro guy but may be in the nitro world is different. The part throttle makes the ESC work Much harder and heat builds up much quicker. So if you think in order to keep the amp draw manageable all one has to do is use part throttle, it does not work that way in reality. If you want 6s set up, get a set up so you can run full throttle all day long.

AlanD
04-02-2013, 10:35 PM
I don't mean to hog this thread so let me know if I should create a new one.

It almost seems counter intuitive to go from 4S / 2200kv to 6S / 1600kv. Sort of changing your car engine from a 4 cylinder 6 speed, to a V6 with a 4 speed transmission. Am I correct to assume folks are putting in the 4082/2200kv to get blistering speeds for 2 minutes and then having to take a few minutes break to let it cool off? I understand their desire to do it I just want to understand what the implications of a setup like that imply.

So your suggestion to go with the 1600kv is to have slightly lower performance but less risk of overheating and possibly longer run times? I think I understand now.

Now that I've done some homework, that Neu Castle 1515/1.5Y is looking tempting too. I might have to refinance the house to buy it though.

lenny
04-02-2013, 10:42 PM
What S would you be running the neu 1515 1y on ?

tlandauer
04-02-2013, 10:58 PM
To get similar performance, if you use higher cell count and correspondingly lower kv motor, your amp draw is lower, yes, it is more reliable and desireable. I have a 12s set up on a Neu 2230 , the kv is only 725, at 32,625 rpm, the amp draw is lower than say, an 8s, 1100kv set up with 33,000 rpm.
On a Neu 1515 1y, there are 5s set ups with relatively small prop like m440 on a Mean Machine for instance. I think the Neu can tolerate this higher rpm to a certain extent, their materials ( bearings and magnets) being superior and the quality is Made in the US, I won't go for 5s on a 2200 kv Leopard.

AlanD
04-02-2013, 11:02 PM
I'm assuming 6S as as described above. I'm still shopping around.
Castles web site refers to using 4S2P with it on the Blackjack. Castle doesnt mention 6S with it but a user on another forum had it setup on 6S. Any thoughts on it?

tlandauer
04-02-2013, 11:06 PM
The 4 cylinder and V6 comparison is only true to a certain point: the V6 has more torque and can use a higher gear to obtain a certain speed within a given time, the 4 cylinder would have to work harder in a lower gear and turn faster to get enough torque to obtain similar speed in the same amount of time. In my mind therfore a V6 will last longer. But I could be ridicured here too for saying this.:hornets_nest:

tlandauer
04-02-2013, 11:08 PM
I'm assuming 6S as as described above. I'm still shopping around.
Castles web site refers to using 4S2P with it on the Blackjack. Castle doesnt mention 6S with it but a user on another forum had it setup on 6S. Any thoughts on it?
Are you talking about the Castle/Neu or the Neu 1515, they are different motor, one is made in China and the other is made here in the US, I have the US made one in my Mean Machine and the member who was helping my build runs his with 5s set up , with a smallish m440 prop.

lenny
04-02-2013, 11:13 PM
If you want a 6s setup,
Why not save a little money and try what my buddy is running in his geico.

AlanD
04-02-2013, 11:15 PM
I was referring to the Castle/Neu. Didn't realize there were 2 options. I'm beginning to think there is now reliable solution for 6S.

AlanD
04-02-2013, 11:17 PM
Lenny, tell me about his setup.

lenny
04-02-2013, 11:23 PM
I am still testing my setup in the mystic,
And it is running on two 4s 40c 4000mah pack and nice and smooth with a gps speed of 56mph,
And that was with some old packs I picked up with a boat on hear.

lenny
04-02-2013, 11:37 PM
This is his boat,
Not sure if he gps it yet.
I could find out from him,
He is using a 130amp hv seaking esc for good head room.
On 6s with this motor.http://www.hobbyking.com/hobbyking/store/__17720__XK3674_B_1400KV_Brushless_Inrunner.html
And loves it, Told me it is a great motor and he has tried a lot of setups in a lot of boats.
But cat hulls are his favorite.

http://www.youtube.com/watch?feature=player_embedded&v=Poz3OC9cSlM

http://www.youtube.com/watch?feature=player_embedded&v=d2EpdYjfidk

Tell me what you think of it.

olwarbirds
04-03-2013, 03:17 PM
We run a leopard 4082 2000KV with a seaking 180amp with cap bank on 6S with NO overheating probs...have run on the stock prop and others with NO overheating probs...OSE has had the leopard 4082 2000kv and 2200kv motors custom wound so they can handle 6S...If your looking for longer runtimes then yes drop to a 1600/1800kv ...our setup was just us trying to see just what kinda speeds could the BJ29 handle ... 6S setups on boats this size are not for everyone! Im a speed demon, I enjoy SAW runs and will be competing in future events along with other types of FE boat racing events....

Im very familiar with NEU motors from being a Jet junkie for many yrs...I use them for SAW setups...The NEU 1515 1Y is a 2200kv that is rated to a max 27v and a max 60,000 rpm, so their is no reason you couldnt run it on 6S ...I would personally NOT use it for a sport setup, thats more of a SAW setup, I would use the leopard 4082 1800kv-2000kv...each to their own madness...

Alan, this motor mount is very nice ....OSE-80610 ...its easy to install and distributes the weight of mtrs like the leo 4082 nicely, plus the price is very reasonable....

AlanD
04-04-2013, 12:01 AM
Lenny, that MG is very impressive and he seems to get good runtime too. Is he on 4S or 6S?

Olwardbirds, thanks for all the good info. That gives me confidence that I can continue with a 6S setup. I would love to see photos of your setup and how you mounted the new motor bracket. I'm leaning toward the 4082/Seaking 180 combo with 1800 motor. Do you know if the 1800's are custom wound?

I since found part of my burnout problem was that the junky stock flexcable was binding in the leading edge of the strut bushing putting excessive load on the motor. I pulled the cable out after finding it didnt rotate freely, and where the flex portion joins the solid section its not aligned so its wonky when rolling it on a flat surface. OSE has an upgraded cable AND a new strut with better bushings for the BJ29 coming out in 3 weeks which is a straight replacement of the stock strut. I'll be doing that too.

Guys, thanks again for all the good info.

lenny
04-04-2013, 12:27 AM
Yes on two 3s 40c 5000mah packs in series.
In the video,
I do not think he was pushing it to hard that day.
And also not hitting full throttle ether,
Just cruising power on a sunday after noon.

jsturess
04-04-2013, 09:00 AM
OSE has an upgraded cable AND a new strut with better bushings for the BJ29 coming out in 3 weeks which is a straight replacement of the stock strut. I'll be doing that too.

More info please, pictures?

jsturess
04-05-2013, 12:52 AM
Ive got this frome OSE "they have replaceable bushings for a 3/16" shaft"

macace123
04-05-2013, 01:34 PM
i glued two magnets up front and cut weights that fit up front and it works well no bounce and still fast. i take pics and post

hydro_pyro
04-05-2013, 02:31 PM
If the strut is up high enough (but with no angle) and there's a bit of surface chop on the water, this boat does not bounce, even when it's COG-tuned to fly the bow high. Smooth water is sticky. It needs the chop to loosen it up.

By putting tons of weight forward, you completely circumvent the catamaran design, forcing it to run like a three-point hydroplane instead of a tunnel. Ppfftt...

tlandauer
04-05-2013, 07:48 PM
If the strut is up high enough (but with no angle) and there's a bit of surface chop on the water, this boat does not bounce, even when it's COG-tuned to fly the bow high. Smooth water is sticky. It needs the chop to loosen it up.

By putting tons of weight forward, you completely circumvent the catamaran design, forcing it to run like a three-point hydroplane instead of a tunnel. Ppfftt...
:iagree: The strut height is the deciding factor and the ride pads surfaces have to be trued and blue printed, battery position is secondary and adding more weight in the front is of no consequential effect in the final analysis. Been there and tried that, learned the hard way by not believing what I read from people with more knowledge on these issues.

AlanD
04-06-2013, 06:41 AM
Olwarbirds, I'm going to go with your suggestion of the OSE motor mount with the 4082/1600kv / 180 combo. Can you share some closeup pics of how you installed the mount? Did you have to cut any of the stock wood motor support away, and where did you locate the ESC? The wires on the 4082 look pretty short so I'm curious if you put the ESC upfront.

AlanD
04-06-2013, 06:44 AM
Jstuess, I don't have any pics, just the email from Steve at OSE stating they are "2-3 weeks out" on the strut.

Barrel Roll Joe
04-06-2013, 10:08 AM
I would suggest reinforcing the hull with fiberglass if you plan on running it fast. I have renamed mine CRACKJACK!!!!!!!


http://youtu.be/1-T1882YfnY

Barrel Roll Joe
04-06-2013, 10:22 AM
The seam that runs around the middle of hull is joined together with the weak epoxy that they use to hold down the battery trays. I glassed the inside of hull and relocated the water outlets.

96814968159681696817

I guess I should rename it BlueJack now!

tlandauer
04-06-2013, 12:39 PM
I would suggest reinforcing the hull with fiberglass if you plan on running it fast. I have renamed mine CRACKJACK!!!!!!!


http://youtu.be/1-T1882YfnY
Very nice footage, great running boats!:buttrock:
Exact same thing happened to me, same kind of crack, reinforced from inside and in the bow area I poured two-part foam, alot better now. I like your new paint job. I didn't, just found some funky yellow-lime paint and touched up my MG.
Also really dig your rescue boat! Which one is it? I have bad eyes, :olleyes:

BHChieftain
04-06-2013, 10:33 PM
If the strut is up high enough (but with no angle) and there's a bit of surface chop on the water, this boat does not bounce, even when it's COG-tuned to fly the bow high. Smooth water is sticky. It needs the chop to loosen it up.

By putting tons of weight forward, you completely circumvent the catamaran design, forcing it to run like a three-point hydroplane instead of a tunnel. Ppfftt...

+1! I have been messing around with my son's new Miss Geico V2. We are running it stock with an x642 prop. I did need to grind the strut bracket slot so I can move the strut up and keep a neutral propshaft angle. I have the batteries back but not all the way-- for our setup the best performance is the edge of the lipo about 1 inch in front of the wood motor "cage". For sport running with glassy water, I still get some bounce, but when racing with some chop, it handles great! I think if I blueprint the sponsons I can improve the bounce on smooth water.

Chief

Barrel Roll Joe
04-06-2013, 11:10 PM
Its my buddies not exactly sure what type of boat the rescue rig is but its definitely a life saver. I ordered some of that two part foam but im unsure on how to get it into the bow without making a mess. Did you add a little at a time until it was full? can it expand too much and crack the hull?

tlandauer
04-07-2013, 01:08 AM
Its my buddies not exactly sure what type of boat the rescue rig is but its definitely a life saver. I ordered some of that two part foam but im unsure on how to get it into the bow without making a mess. Did you add a little at a time until it was full? can it expand too much and crack the hull?
It really was great to see the rescue rig doing its job. I always had trouble lining up the fork and so I gave up this method and just make sure I tape up well and incase of a roll over, it would hopefully float long enough for the wind to blow back. :Praying::scared:
As far as the two-part foam, I was concerned that it might crack the hull, but as long as there is escape, it will expand to that space, so, there is really no chance for this to happen because the front under deck is open. What I did was to buy those clear plastic disposible party cup ( glass) , then using my regular mix cups:http://www.offshoreelectrics.com/proddetail.php?prod=dh-gpmr8056, one cup for part A and another for part B. You reuse the small mix cups with the same part but discard the party glass after each pour. For my first pour ( since i didn't know the expansion rate) , I used half cup from each part. Pour both into the big cup and stir quickly, then pour. You really have less than a minute before you see it expanding. It will help if someone will hold the boat for you straight down, and eye ball the opening of the hull before you attemp your first pour, it takes mental planning ahead. I aimed at the tips of the sponsons first, left and right two separate pours, when that is filled up, then middle, try to maintain a leveled rise . Always wait for the foam to expand fully before the next pour!
The other thing I read is that one should only do this when outside is at least 70* F, I remember someone said that the foam expanded a bit more when outside was hot, I did not experience that because I live in So Cal. The two part foam sold by Kintec is quite good, there was another kind that would do strange things whenever there is drastic temp change: one would see the deck either gets "suck" down or "pop up" .
I would do a search on the Forum and read what others have done.
Cheers!

jsturess
04-07-2013, 04:24 AM
Hi

I used this http://www.danalim.com/product-catalogue/construction/pu-foams/2c-polyurethane-foam-596/ and filled all at once, it expands very little.
Tip, do not remove the Styrofoam piece, I did it and had to do this twice, it keeps the shape :-).

Regards Johan

BHChieftain
04-07-2013, 10:33 AM
It really was great to see the rescue rig doing its job. I always had trouble lining up the fork and so I gave up this method and just make sure I tape up well and incase of a roll over, it would hopefully float long enough for the wind to blow back. :Praying::scared:

Another rescue options that works great for me-- put an eyehook on the back of the transom of your rescue boat an either haul out a fishing line, or tow a tennis ball about 3-4 feet behind the boat-- drive around the stranded boat and either reel or tow back in. I use a traxxas blast as it has very good maneuverability at slow speeds.

Use a drinking straw at the transom end to keep the fishing line away from the prop. In this picture I am using the proboat rescue duck gaff to hook the boat, but a tennis ball works well too.



Chief

olwarbirds
04-08-2013, 03:52 PM
Hear all of ya on the cracking hull issues...my buddy hit something submerged with rudder and the transom busted out and we got hull seperation issues happening now too....BJ is being stripped and re-done...going to make a transom doubler out of some hardwood, them I'm going to lay CF throughout the hull....probably going to layout inside of hull differently too...Yes ESC in front of the Motor, trying to keep wire runs as short as possible...We are NOT in anyway dissappointed with the BJ29 hull...this boat has taken some serious abuse...I'm impressed that the hull hasnt shown more damage considering some of the 65mph plus tumbles its taken... DJ

onadskee
04-16-2013, 05:05 AM
[QUOTE=MAMBA2200;472742]These hulls are good at bouncing you will find that a cat hull will be smooth then bounce and then smooth out again once you get fast enough. What i have done to calm mine down is set the strut about 1mm above level and angle it down about 1mm. But what you must take into consideration is that no matter how hard they try every hull is different so it will be different for every boat out there on setup. So try to use my setup and see if it works for you it might it might not but it is a starting point. Hope this helps you:beerchug:[/QUOTE

Hello hope you ok, can you please explain when you said you set the strut up 1mm above level then angle it down? How did you do that? I can only raise the strut up or down but not sure how to angle it down. Thank you.

hydro_pyro
04-16-2013, 07:54 AM
There's a bit of wobble in the strut that should allow a little bit of thrust angle adjustment, as well as the ability to change its vertical position. Put the boat flat on a clean table and raise the strut up until there's a 1mm gap between the strut and the table surface, and angle the strut slightly down as you tighten it. This will give you maximum stern lift to minimize the bounce. I think mine is set even higher than this.

You may need to grind and egg-out the mounting hole bigger to get the position you want.

It helps to have a friend tighten the screw while you hold it in position.

Barrel Roll Joe
04-16-2013, 08:20 AM
Hey DJ I'm running the 4082 2000kv and I'm noticing my battery life has been cut in half or less do you have the same issue? Should I play with the timing to improve this maybe?

tlandauer
04-16-2013, 01:03 PM
There's a bit of wobble in the strut that should allow a little bit of thrust angle adjustment, as well as the ability to change its vertical position. Put the boat flat on a clean table and raise the strut up until there's a 1mm gap between the strut and the table surface, and angle the strut slightly down as you tighten it. This will give you maximum stern lift to minimize the bounce. I think mine is set even higher than this.

You may need to grind and egg-out the mounting hole bigger to get the position you want. It helps to have a friend tighten the screw while you hold it in position.
That is exactly what I had to do, the little wobble allows the strut to have the negative thrust angle you need while setting the strut high. This is seldom mentioned on these posts when people ask how to raise the strut ( correctly)!

AlanD
04-17-2013, 10:39 AM
I just did this with the stock flex cable and strut, and when I angled the strut downward, it placed pressure on the joint on the shaft cable where the flex and solid parts are joined. My stock flex cable is badly aligned and the negative strut angle exagerated the problem.

So, when angling the strut down, be careful of any added friction you might be placing on the flex cable so you dont add excessive load the motor and fry it. You want the base of the strut angled slightly down relative to the hull but make sure the flex cable housing is in alignment with the base of the strut too.

I hope this makes sense to readers.

macace123
04-17-2013, 11:20 AM
can anyone post picks of the back of there BJ29s i still cant get my boat tuned right

lenny
04-17-2013, 07:09 PM
Post some pictures of yours and where you are placing you cell to,
Than may be we could help you with how it runnig.
Have any video's of it running to see how it is riding for you ?

Scaler15
04-17-2013, 11:46 PM
Not quiet the right topic but... I am ordering my first rc boat this weekend. I am still stuck between the blackjack 29 and the impulse 31. Ill be running them on dinogy 4s lipos in parallel. I will be running at a lake woth mostly calm water but choppy in some spots for ome fun. Is there any huge differences between the boats, will the v hull give me a better run time? If you guys have any input on which model i should choose i am wide open for opinions!

macace123
04-18-2013, 10:12 AM
i will post pics and videos for you to look at this weekend lenny. Scaler i say BJ29 it all around halls ass.

Scaler15
04-18-2013, 05:40 PM
i will post pics and videos for you to look at this weekend lenny. Scaler i say BJ29 it all around halls ass.

Thanks macace!!! Do you think there is any noticable runtime differences between the two??

macace123
04-19-2013, 03:56 PM
no my impules rips just as fast bj29 handles smother run times are about the same.

ray schrauwen
04-19-2013, 04:13 PM
So you got that deal on Ebay huh? Nice Score and nice paintwork!! :thumbup1:


The seam that runs around the middle of hull is joined together with the weak epoxy that they use to hold down the battery trays. I glassed the inside of hull and relocated the water outlets.

96814968159681696817

I guess I should rename it BlueJack now!

Scaler15
04-19-2013, 06:19 PM
Thank you guys so much for helping me! I just ordered the blackjack 29 cqnt wait to start running it!!!!

macace123
04-22-2013, 03:52 PM
just make sure you change the esc an motor connectors to 5.5 the stock connectors with blow solder all over the place i learned it the hard way. and sharpen the stock prop and it will scream. have fun with it i do all day

Scaler15
04-22-2013, 06:36 PM
Ok thanks macace can you point me in the right direction with the 5.5 mm bullets. Is there anything else needed for good running?
I am thinking of doing ec5 on the batteries.
Is there anything wrong with a 6 or 6.5 mm for the motor cause if im changing it wouldnt your just get the biggest you can find, sorry im a noob to boats!!

BHChieftain
04-22-2013, 10:46 PM
Ok thanks macace can you point me in the right direction with the 5.5 mm bullets. Is there anything else needed for good running?
I am thinking of doing ec5 on the batteries.
Is there anything wrong with a 6 or 6.5 mm for the motor cause if im changing it wouldnt your just get the biggest you can find, sorry im a noob to boats!!

You should use the bullets on everything including the lipos. That way you can avoid using a harness. You take the positive lead of one lipo (female bullet), and plug it directly into the negative lead of the other lipo (male bullet). Then you plug the remaining 2 lipo leads directly in the ESC leads.

But you have to be careful not to dead short the packs (I've done that more than once)...

Chief

Scaler15
04-22-2013, 11:06 PM
Ok thanks chieftain for the information i need as much as possible haha, this deadshorting doesnt sound good! I need to run the lipos in parallel. Do you know how i could achieve this?

macace123
04-23-2013, 10:02 AM
i am running EC5s on the ESC and Batteries and 5.5 on the motor to ESC i just ran 44.5 on a octtura m445.

jsturess
04-23-2013, 11:17 AM
Can we be kind to stick to the topic

hydro_pyro
05-14-2013, 10:03 AM
This is the ticket:

http://forums.offshoreelectrics.com/showthread.php?41146-Miss-Geico-dialed-in-strut-modification

don83000
05-18-2013, 12:47 PM
no additional weight just set cog at 33% and I'm golden.

When you say 33% are we talking 33% of the sponson length or the complete hull and strut. So I assume you advize running 2x4s 5000mah in parallel.

Thanks Don

hydro_pyro
05-19-2013, 09:30 AM
Here's mine... strut hole egged out, raised, angled, and aligned. No bouncing.

http://i1247.photobucket.com/albums/gg629/hydropyropyropyro/D897E138-AEC6-42EC-AD3E-E45DCC4F0EA0-28333-0000330DAD47EAA7.jpg

Simply moving the batteries far forward as others have suggested does not correct the problem. It just makes the front of the boat "plow" while the back end "digs in." Raising and angling the strut downward gives the boat the stern lift it needs, and the packs don't need to be moved as far forward, because the hull doesn't tend to trap air when it runs high and dry.

Even when it gets tossed around in the chop, the bow doesn't rise, it just settles back down again.

AlanD
05-26-2013, 02:10 PM
Hydro, I put a sharpened balanced m440 on mine and set the strut the same as in your pics. I moved the batteries so the cog is between the motor face plate and the bulkhead supporting the top of the stuffing tube.

Result, the prop cavitated a lot but reached peak rpm easily. Bouncing like a lunatic and could not sustain WOT without twitching and wanting to flip. I'm not sure if it was the prop change, the strut angle or the COG change which caused the negative performance. Tried dropping the strut again but didn't help. I wonder if the tongued stock prop is better suited to my leopard 4082/1600 than the m440 since the 440 has slightly.less.pitch.

Any thoughts?

don83000
05-26-2013, 02:43 PM
Thanks Hydro I did as you said and hell that runs sweet chuffed as you can get and first timeout of the box and on the water and there was quite a chop on the water and it loved it. Best boat I've ever had. A big thanks to all that have given me their time and advice.

AlanD
05-26-2013, 04:33 PM
Just got back from the lake after putting my stock prop back on. Much better handling and performance than the m440. Still some bouncing when running in the high 50's but I can live with it. The strut angle is exactly as pyro has it. I really thought the m440 would give me a better top end to push through the little bit of bouncing at top end. That certainly was not the case here.