bloodtight_18

i am new to the boating side of rc i am making me a home made hull right now and i am going to put 2 electric 380s in it i was wounderin how could i do this without getting a leak in the back of the hull i want to put the 2 engines inboard but when i put 2 holes in the back then put the shaft through it what am i going to have to put around it to keep water from getting in the hull? i hope you understand what i am saying help would be very thankful

canadianjosh

This is called a stuffing tube. Depending on where you mount your motors determins the length of it, but basically it is a brass tube that is a bit larger than your prop shaft and this is filled with grease to prohibit water entry.

bloodtight_18

thxs man can i buy these off the internet or is there a way i can make them? also how can i make 2 motors run off of one speed control or can you even do this??

Tachikaze

I will be posting a pictural of placing the stuffing tubes into a boat this week. I finished the work over the weekend and will be posting to my site this week.
Stay tuned

bloodtight_18

well i desided i am just gonna run one motor not 2 so all i need to know is how to make a stuffin tube or were to buy one

TERBObob

My Feedback: (21)

Go to your LHS ( local hobby shop ) and get the size brass tubing that your flex or solid drive will fir into as tight as possible , but , without sticking .
Then take that tube and make sure it is long enough to go from the area where the prop is ( the name of the item I am referring to is called a STRUT . This is the item that is attached to either the transom ( read par that is 90 degrees to the water ) or it will attach to the very bottom , near the back of the boat . The other side , you want to make sure that it comes all the way up to the where you have the motor ( remember - its always easier to cut some off , then try and add some )
Then what you will need to do is figure out for sure , if you want twin motors going to one outdrive shaft , or one motor-one shaft .
Yes , they DO sell and make those gearboxes - two EP out to one drive shaft . ( whether its flexcable or solid )

You could make your own using these for example :
http://www2.towerhobbies.com/cgi-bin...?&I=LXE522&P=0

or you could use one like this:
http://www2.towerhobbies.com/cgi-bin...?&I=LXS931&P=7

If you look at this page , you will see the brass stuffing tube that has the drive inside of it . If you look down the page further , you will see how the stuffing tube is a little larger diameter than the drive .
http://www2.towerhobbies.com/cgi-bin...?&I=LXE421&P=0

Here is an example of a EP ( electric power ) stuffing tube with shaft ( drive )
http://www2.towerhobbies.com/cgi-bin...?&I=LXE431&P=0

Also , realize , that most EP drive use the follwing type connections ( not all , just most )

This first part , will either screw onto yor shaft of your gearbox , and it also screws onto the shaft at the end ( some , like this one , has a set screw you tighten )
http://www2.towerhobbies.com/cgi-bin...?&I=LXE526&P=0
, now , if you need to have a flexable joint , at the end , near the strut , this is like what you would use
( here is a typical strut for you to view ) ( its the goldish colored piece that is all the way to the left side and big )
http://www2.towerhobbies.com/cgi-bin...?&I=LXE422&P=0



This next piece is to connect the motor to the drive , if doing a direct hookup , meaning that if you decide to go one motor , one drive shaft , then you will need this in between the motor and the shaft . ( connected using the item above . Reason for using this is in case your hook up is not exactly in line .

http://www2.towerhobbies.com/cgi-bin...?&I=LXE526&P=0

Now , pending on the hull you have , as to which way you want to setup the stuffing tube ...
If its a deep vee ( mono ) , then most of time , you would have the stuffing tube exit the very bottom rear of the transom . If its any other type of boat , then most of the time , it exits thru the bottom of the boat , whereas when you put it in , it does not allow any kink in the sutffing tube . And if using a straight shaft , then , of course , you need to make sure that it has as little of angle as possible .

bloodtight_18

thxs you help alot i am gonna put one motor in it alot less hasel and when i want more speed i can just upgrade one motor and not two thxs i have a deep vee hull so i will take your advise and i dont quit understand how will i hook up the motor to the drive shaft??and what prop is the best??

TERBObob

My Feedback: (21)

Ok .... the prop size , sorry , but thats something that someone else will have to pipe in on . But how to hook one motor to one drive is simply .


First , the motor ... now we need to decide , are you going to go with what is called a FLEX SHAFT or a solid one ? If flex shaft ( which is best decribed as the inside cable to a cars speedometer ) .
The parts you will need are as follows :

collet ( an item that screws onto the motor and tightens around the flexshaft , kinda like what a drill chuck does . )
Then , of course , the flex shaft and stuffing tube . The flex xhaft goes INSIDE the stuffing tube and exits out the back .
Ferrule

- this would be the part that is made of brass and connects the flex shaft to the prop shaft ( aka - stub shaft ) . The front part , which connects to the flex would be either soldered on with silver solder , or you can buy them premade and then they are welded and yu would not need the ferrule .
The back part of the ferrule has either one or two set screws , which you will slide that part of the ferrule over the prop shaft and tighten the screws . ( it is also suggested that you "notch" the prop shaft where the ferrule would set on the prop shaft for a non-slip connection )
Then , you need a strut . This is like the following . ( but does come in different varieties , but this picture s of the design you would need for a deep vee ) ( ignore the copper colored piece in the picture ... and FTR - this picture is only for reference and not the actual size of one needed )


Then , you will need the prop shaft ( stub shaft ) to go thru the strut to hold the prop in place ( the one in the picture also has a DRIVE DOG and PROP NUT on it . The DRIVE DOG is the silver colored piece and the PROP NUT is the copper colored item )


The drive dog is used to hold the prop in place and to not allow it it slip . The prop nut is there to make sure that the prop does not fall off .
If using a flex shaft , you will also need additional items called telfon liners for the strut and or brass tube bearings ( which is the copper colored item in the other picture I told you to ignore )


Now , if using a straight solod shaft , then alot of this you will not need .

If straight , solid shaft , then you will need to connect the motor to the drive shaft with one of these :

Then , on the end of the solid shaft , you should have it already threaded , but if not , no biggie .
If threaded , then all you will need is a drive dog ( as above ) and a prop nut ( both of which go on the furtherest outer part from the strut ) The drive drive dog goes first , then the prop , then the prop nut .
Now , if your drive shaft is NOT threaded , you can simply notch the shaft in a spot AFTER it goes thru the strut and this would be where you put the drive dog , then the prop , then another item that is very much like the drive dog , BUT , without the notches . ( shaft collet )
Now , with a solid shaft , you do not need thrust washers , but , if you use a flex shaft , you will need them . Thrust washers are just that - washers that are put before the drive dog , on the prop shaft , to allow for when the motor torques out and will tighten the flex shaft . ( under load )
The following is an example picture of these .


Now , here is what a strut shaft setup looks like for a flex shaft setup :


photos courtesy of AEROMARINE RC , Tower Hobbies , and ROCKET CITY RACING

bloodtight_18

well sorry to tell all of you this but i have desided to make a airboat not a deep vee to much work and will take much needed time that i dont have and i love the idea of being able to go were other boats cant but if you could help me on this how would i hook up the big fan to the motor would it be the same way as i would with the regular boat or would it be different i am sure it will be a little different and what size would be a good size for the hull for my 380 motor? help would be apreciated thxs [&:]

BONESLASHER04

shouldnt the stuffing tube be shorter the the prop shaft as in the second post was wrong.

TERBObob

My Feedback: (21)

Yes , the stuffing tube is shorter after cut to exact size needed , but initially , you want longer so that when you cut , you cut it to correct length .

And about the airboat ... come on over to the AIRBOAT section here on RCU ... ( yep , I'm there BIG time also ... )
ALthough , I am really up on electrics , I know that one of the other fellows will SURELY be able to assist . [8D]

Tachikaze

I have posted the construction of the stuffing tubes for HIJMS Shimakaze, a 1/72nd scale combat warship.
[link]http://groups.msn.com/QueensOwnAxisCommand/newconstruction.msnw[/link]