Fixing the BJ26 Handling Issues

[PropNutt43]

This is a copy and paste from another thread I posted in. It gives some general info on drive hardware.

Quote:
Originally Posted by lyndon915
I have been all through the handling issues thread. I have seen the fuller hardware and am just wondering what some of my other options are and what I am going to gain by running an inline rudder or an offset.


Inline hardware:
Will give you almost equal turning both right and left, I say almost because the torque from the motor and rotation of the prop are factors too. Will also lose a little speed because the rudder is in the path of the props thrust.


Offset hardware:
Will give you superior turning in one direction, the direction depends on which side the rudder is on. Should run faster because there is nothing in the path of the props thrust.


Other considerations:
The distance between the rear of the transom and the prop will affect the boats speed and stability and how easy it blows over backwards.

The farther back the prop the more stable and less likely the boat will blow over because the prop has more leverage to keep it from happening.

The closer to the transom the prop is the more speed you should be able to get because the boat will easily get more airborne, but might blow over easier.

If that doesn't help keep looking at the different threads in these forums they will help you make your decision.

https://forums.offshoreelectrics.com/...ead.php?t=3643

[chirotray]

Thank you for the info, most helpful. It kinda sounds like a ford vs. chevy issue.

[wafel1978]

Hi Guys !!!


I am building Dumas “Tuna Clipper” (Wooden Boat). I am going to install [Pro Boat----Blackjacks 26 Brushless] Electronics and Brushless motor to her .

I am seeing mods you guys did and I am absolutely impressed.


1. Wondering if the Fuller’s off shore Hardware will be right (good) for this kind of boat ?

Length of boat 37 inch
Wide 8 inch

Maybe you can folks recommend some, I want this boat to be fast .
Waiting for advices.





Thank you for reading
Greeting Pawel

[RCprince]

You may need to make your own thread, you sorta hi jacked this one.

[chirotray]

Just as a quick pointer even though this boat is way off topic, the hardware and electronics here in this thread couldnt be any more wrong for that boat. Something like that go with a 12 volt system so you can have power and ballast taken care of in one shot. Thats always worked well for me on more "scale" projects. But like RCprince said, if you want peoples full attention to help you, start a thread of your own in an appropriate column so that the right people will see it. Back to the BLACKJACK!

[po-boyz]

The stock controller is suppose to take 24 V. I have 2, 3 cell Li-Pos. 4000 mah each.
Nothing has cooked. Boat neeeeds, I mean neeeeeds rudder to control it.

[wafel1978]

ok.

I start new thread, if any one of Blackjacks expert want to post some reply please go to

https://forums.offshoreelectrics.com/...ead.php?t=4010


Sorry about posting in Blackjaks thread.

[chirotray]

The stock controller is suppose to take 24 V. I have 2, 3 cell Li-Pos. 4000 mah each.
Nothing has cooked. Boat neeeeds, I mean neeeeeds rudder to control it.

Im not sure if you meant this to be in response to what i told the gentleman about a 12 volt system, but if it was, i meant a 12 volt as in larger gel cell type battery that is very heavy to provide ballast and tons of run time for a scale type boat.

[MAXAMUS]

Hi all

so the saga continues still no darn boat been 3 weeks or more looks like there is an import / distribution problem to the UK but on the brighter side i have now wrangled a deal with a lhs in Florida who had 3 in stock and as we speak is processing my order after a lengthy phone call and is shipping out this Monday 30.6.08 tomorrow i will be phoning my lhs here to get a refund and tell him the good or bad news however he looks at it lol.

I have all the extras in fact i am all ready to go I've 2x 20c 6000 mah lipo's ,antenna mod /mount, a balanced/sharpened x642 octura prop the programming card a 2.4 GHz Rx and TX well this pending a fatal crash of my RC plane lol but can't say when that will be, also awaiting fullers hardware so as you can see there is only one thing missing yep something to put it all in

when you guy's use hatch tape do you seal the hatch all the way around ? or just a few strips to secure the hatch? is the tape mainly for hatch security or when sealed all the way around for anti water penetration ?

also i am wondering if anyone polishes the hull or applies anything to help the boat cut through the water and reduce drag ?? just a thought

[chirotray]

I use hatch tape anywhere water can penetrate, dry is good. And lightly scuff the bottom of the hull.

[MAXAMUS]

why what does lightly scuffing the hull do i thought it would need to be smooth as??

[chirotray]

Scuffing helps the boat to break the waters surface tension better. Basically lets microbubbles up under the contacting portion of the hull to make it scoot faster. I know its opposite of what you might think, but its proven. Theres a few threads on here that really explain it.

[MAXAMUS]

i see and what would you recommend doing it with a scouring pad lightly from nose to tail ??

[chirotray]

some guys use like 600 grit, i just picked up the first piece of sandpaper that was in my drawer and went to town. It doesnt take much, and I only did the parts that I felt like would be in the water the most. (back 3/4 or so)

[spinner]

Well I tried my Blackjack with the fins angled inwards, with stock hardware. It definately does not help. The boat hooked real bad coming out of corners and lost some straight line speed.
]

[hex-dj]

Well I tried my Blackjack with the fins angled inwards, with stock hardware. It definately does not help. The boat hooked real bad coming out of corners and lost some straight line speed.
]

True. Mine even flipped from the left side from a very sharp turn. It does not help. I was using an Ammo 2300 kv though.

[PropNutt43]

As I have said before I never ran the fins angle with the stock hardware on my boat.

What I can tell you is that I did have the same problems of hooking (spinning out) and losing some speed when I first put angle on the fins.

After running "many times" playing with the prop angle and depth, moving the center of gravity back, and shortening the fins all that went away.

[PropNutt43]

The Problems:

Angling the fins at the stock length causes the boat to run wet, meaning it pushes the front of the boat down.

Running wet reduces your speed and affects the boats turning causing hooking (spin outs).

Fixing the problems:

Shortening the fins reduces the affect of pushing the front of the boat down. 1/2 to 1 inch below the ride surface works best. More stable at 1 inch but much faster at 1/2 inch.

Moving the center of gravity back at least 1 inch will eliminate the hooking
(spin outs).

Raising the prop height and adding a little positive angle will get the speed back up.

[PropNutt43]

Also I have seen pictures on the forums of the turn fins being bent to put angle on them. Only by leaning them over can you be sure they are at the right angle in relation to the length of the hull. If the angle is off it could cause the boat to track funny or even hook.

[chirotray]

I dont have the upgraded hardware yet, but ive been playing just with center of gravity and prop angle. And on my boat with the cg back a bit, and prop up a bit, it aint too bad! Prob not race competitive, but plenty to impress people at the lake! The more i drive it the faster im comfortable turning. I think a little practice on this boat goes a long way.

[rahallva]

Thanks for the info on the turn fins guys . Will wait on angling them awhile

[MAXAMUS]

yipeeee

its arrived at last fresh from Florida in under a week !!

OK to work 1st question the motor mount is not parallel the wooden base mount should this be ?? see attached picture

also what are you guys blocking up the canopy semi circular holes with + antenna hole ? also where the water pick up rubber tube enters the hull at the rear are you waterproofing this and with what ? that should keep me busy for a while now to start some mods

a happy maxamus........

[Wakesurfer]

Wow, the motor mount is looking pretty far out. Try to line it up so it's square and centered on the shaft log. A little clear hatch tape over the hole in the canopies will help keep water and dirt out the pilots faces. I've had good luck taping the hatch down with white electrical tape. Sticks well for keeping the edges sealed but comes off easy after a run. I used it to tape around the ant. hole too, until I ditched the stock Rx for a Spektrum. Never had any leaks around the cooling hose. Big common leak is at the end of the shaft log. Cut about 3/8" off of one of your cooling hoses and slip it on over the end of the log. Put the shaft back in and slide the tube forward so it just touches the shaft and it will help keep it sealed up. Grease the shaft well too. Have fun with it.

[MAXAMUS]

Wow, the motor mount is looking pretty far out. Try to line it up so it's square and centered on the shaft log. A little clear hatch tape over the hole in the canopies will help keep water and dirt out the pilots faces. I've had good luck taping the hatch down with white electrical tape. Sticks well for keeping the edges sealed but comes off easy after a run. I used it to tape around the ant. hole too, until I ditched the stock Rx for a Spektrum. Never had any leaks around the cooling hose. Big common leak is at the end of the shaft log. Cut about 3/8" off of one of your cooling hoses and slip it on over the end of the log. Put the shaft back in and slide the tube forward so it just touches the shaft and it will help keep it sealed up. Grease the shaft well too. Have fun with it.

thanks have lined up the mount removed bat trays done the switch mod just in the final touches of the antenna mount any chance of some pics for the shaft tube ? but thanks alot

[MAXAMUS]

Hi all

well I've just finished work but now down to real work i arrived home to find my fullers cat hardware has arrived so looks like this will take up most of my afternoon all these mods and the thing hasn't been near any water yet ! lol hoping to get down the pond first thing tomorrow and hopefully post some pics and video all going well .......................

could some one please list or point me into the right direction for fitting the fullers cat hardware including fitting and cutting the 150 flexi shaft i know I've seen it somewhere on this forum but cant find it

[lancel]

I believe you mean this pic.

Attachment 4602

What you see is 30 minute epoxy coating the transom at the rear of the boat. I have drilled more than a few holes in the transom and had too removed some of the wood that doubled up the thickness where the turn fins were originally mounted.

Reason for coating:

Wanted to waterproof the areas that were no longer coated in fiber glass. Also to strengthen around the edges and areas where the turn fins and drive hardware are mounted. You can see it better in this pic.

Attachment 4603

Propnutt43 - What brand coating did you use?

"What you see is 30 minute epoxy coating the transom at the rear of the boat. I have drilled more than a few holes in the transom and had too removed some of the wood that doubled up the thickness where the turn fins were originally mounted."

[kookie_guy]

hey propnutt, I borrowed one of your pics to ask a question, hope you don't mind....

1) the red measurement. why is it so long? Could this be shortened to bring the prop assembly closer to the transom and reduce the blue distance? If not, then why?

2) is the green measurement critical? Why or why not?

Thanks for any answers.

[PropNutt43]

Propnutt43 - What brand coating did you use?

Any 20 - 30 minute epoxy will work. I have been using stuff from my local hobby shop. It's distributed by Bob Smith Industries.

Originally I used their 30 minute epoxy but later found their 20 minute epoxy comes in finish cure which leaves a much thinner coat. Thinner coat, less weight, much better.

[MAXAMUS]

OK iam off to the pond tomorrow hopefully armed with a HD video cam and a camera providing my bro in law turns up and weather permitting

have now moved the dog nut away mm's from the strut re positioned the flexi tube to be more parallele, have re greased flexi drive added a bit of shrink tube from the stuffing tube where it exits the hull to the strut to keep water out made another water pick up from brass tubing and a small plate as of propnutt's design. will see how things go and will report back ..............




left to do ..............shorten fins and angle

MAXAMUS........

[Loki]

Ok WOW!

First off fantastic information, but I must say that I’m such a newb I’m a bit scared to just jump in and start doing all the tweaks. I’ve been flying Helicopters for a little while now and just bought an Apache 24 to run around my pool. Needless to say the bug bit me and now I’m looking to get something with a bit more… umph.

I LOVE the look of the BJ26, but now must admit I’m a little worried about how many tweaks it takes to get this thing working… great. So my question is pretty basic.

Should I be looking at another Boat since this one appears to have some issues right from the gate, or is there a version 2 coming out that addresses some of the faults?

Is there a shop that sells the boat and will do the needed tweaks to it or am I looking at doing this myself?

Thanks for any info