ridgewalker

Hello all,
This is my first boat build of any kind.After seeing some of the other members wildthing builds i realized i had everything onhand to build one.
It's 24'' and i plan on running two IB 4200mah stick packs and i will be useing the EVX-2 esc(traxxas) and one 550 emaxx motor 23t.
I will be building all of the hardware myself from alum and brass.I am useing a speedometer cable from a real car to make my flex drive it is a 1/8 dia flex wire.

So what kind of speed should i see with this set up?Will a 24'' wildthing be able to get up on a plane with two heavy nimh bat packs.
I can not aford brushless and lipo,i know that would be better but it is not an option for me.
One more thing i built it all from 1/8 ' plywood lauan door skin,bottom sides and all the bulkheads.

I will take all the help i can get since this is my first boat,i have been into nitro and electric trucks.
here are some pics of my boat so far

Dreamin Hemi

Off to a great start!

ridgewalker

Thanks Dreamin Hemi.
I have added a bit more height to the sides.I wanted to take down such an agressive rake in the front.
I plan on building the strut from some brass tube and a flat.Has anyone built there own strut succsesfully?I don't have a lathe but with a drill press,dremmel,hack saw,cooping saw and many files i can useally come up with something if i can get pointed in the right direction.

How can i figure out how deep to run the rudder?Dose it go below the depth of the hull(the v)

I have looked and readsomany threads about the wildthing so many that i can't remember where i read what.I'm trying to figure out how far from the transom the prop should be.IIRC for a boat of this size 24'' it should be between 2.50''-2.75'' i was going to set it at 2.75'',what do you think?

Could i run the prop directly on my 1/8'' flex wire and just have the stuffing tube run out to where the prop needs to be?I have seen set ups that have no strut just a stuffing tube sticking out with the prop on the end and a rudder for steering.That would seem less complicated to set up am i thinking wrong?

Simon.O.

Have brass and can solder ??
Here is one of mine . This is on my 4S Rigger.....Ignore the prop as it was there as part of my measuring.
There is a square tube on the outside to give me a flat botom strut. All of my other hand made struts are round tube.

As far as prop to transom distance, my research tells me that 10% of hull length is the minimum and you can easily go to 12% with no issues.
My 30" wild-thing inspired hull has the prop a little over 12% but that is because I am after straight line speed, cornering is only to line it up for the straight again.

Keep in mind that it is me and the ducks at my local pond.

ridgewalker

Simon.O. Thank you for those pics that will give me some ideas.Do you have some pics of your wildthing boat you built?

So should the rudder bottom be level with the bottom of the prop? or should it hang below the deepest part of the hull?
Do i have to use a strut?
How should i set it up without a strut just the stuffing tube.Would that be strong enough?

ridgewalker

I am trying tofigure out what kind of cockpit to have.
Here a couple pics of two ideas.Is one better looking than the other?I need some help on what to do with the cockpit.

785boats

Hi there ridgewalker.
You might find a few tricks & tips & things on this rather comprehensive thread on the 'Wildthing' over at R/C Groups. There's over 500 posts so get a cup of coffee first.
[link]http://www.rcgroups.com/forums/showthread.php?t=638510&highlight=wildthing[/link]
What you've done there looks pretty damn good from here.
Cheers.
Paul.

Simon.O.

Paul has the same idea as me.
Take a look over at RCGroups.

Here are a couple of pics of my 30" WT

jdoug

I like the bubble the best! One thing I noticed is how high the stuff tube is in the hull. You should be able to run it a little lower. Get your motor in the lowest possible position,but offthe bottom ofthe hull, also with as little bend in the tube as you can. From there, you can determine where the tube will end up. Looks good so far. I also built a 24" WT as well, but it had a OS .18 in it. Excellent handling boat!

ridgewalker

How low should it go?Would it be ok if it was right on top of the bottom skins where the come together.I will drill a hole right at the bottom of the transom.

I built a rudder and bracket and i want to have equel turning both directions because i wont be racing this boat i'll be just having fun with it of course high speed passes .So i want to mount the rudder directly center after the prop.
How far from the props trailing edge should the leading edge of the rudder be?

Simon.O.

I run my rudder on the right as with most monos, it still turns left ok.
You will not get a surface drive boat to turn equally well both ways as the prop walk will always make it turn better right.
A rudder directly behind a surface drive propwill cause a lot of drag and will not be as effective as one off to the right.
Usually rudders are sited so the leading edge is about inline with the drive dog, there are variations to this guide but as a first buildI suggest you stay inside the ballpark.

ridgewalker

Here are a few pics of the rudder i built with insperation from Simon O.
I know the stuffing box/tube needs to be level with the keel ,it's just resting there right now i'm not epoxying it in untill i know it is in the right place.I can adjust the drive angle up or down because there is a flex wire that i made from a spedo cable i got at the auto parts store inside there.I soldered a solid 1/8 shaft using a small brass sleeve to the flex wire.I will use some 1/8 wheel collars to hold on the prop.

So i know i need to lower the stuffing tube and i will but that aside how does the rudder set up look?Does it seem to be mounted at the right height?The blade is 4'' long 3/4 from the bottom of the blade to the bracket at the top that holds it.

ridgewalker

I posted before i read your post SimomO. so i will move it to the right and keep it in line with the drive dog .I read somewhere to turn the rudder 30 deg and turn the prop1/4 turn and mount it with a small gap between the prop at 1/4turn and the blade at 30*,is this correct info?

jdoug

I think I would have the center of the tube exit the transom close to 3/8to1/2 in. above the bottom of the keel and parallel to the keel as you said before.It looks like youmight have it a little high.If you run it parallel like you have it, it has a good chance of cavitation by not having enough water to bite onto. You basically want one blade of the prop in the water while on a fast plane. You can put a straight edge along the running surface and back to the prop to see about where the prop will be in the water and see what I mean.

Your rudder looks good just as is. I'm not sure what you mean with the deg. of turn, but as long as you have decent rudder travel in both directions without interfering with the prop, it should be fine. Oh, I just saw you have it centered behind the prop, yeah, carry on with Simon O's instructions. He's right about these boats not wanting to turn left until you slow down significantly. ...and it'll do better on the right as far as speed goes.

Hope that helps.

ridgewalker

jdoug iI did some work late into the night last night and i lowered the stuffing tube,luckily for me (i hope because i epoxyed it in)i have it at 1/2 inch from the keel.I took a straight edge and put it along the bottom and 2/3 of one blade is below the keel.I'm not sure what kind of prop this blue one is though but it is about the same dia as a 540 motor so i think it is a 35mm,i will get the #'s from it.

I also made and installed a motor mount.It will allow me to pivot the motor on the centerline of the boat if i need to.

I also made a rudder arm to connect the linkage to and the servo mount.
The rudder has been lined up with the drive dog.I have built in about 1/4'' adj. so i can move it away from the transom or bring it closer if needed.
So any sugestions are welcomed,thanks a lot for helpping me with this first build.

ridgewalker

Those pics in that last post are big on my screen i don't know why,i didn't change anything in my camera.


Here are the numbers for three props i have.Does anyone know if these props will be good to use?
Blue prop are as follows,there are two sets.(38-1.4) and(94431)
Purple prop i have reads (octura Y634)
Red prop reads (octura x431)

jdoug

Not sure on the prop size for you because I'm not familiar with the motor or ESC you are running. Other than that...It looks very good!

ridgewalker

Well i made some progress.
I relocated the stuffing tube so it exits 1/8" from the bottom.I made the buble cockpit from some pink foam i carved then coated with hobbylite filler then i epoxyed it tp the hatch door.,i'm hoping it will mabey help to right the hull in a flip or al least provide some flotation.I also filed the front of the hull with foam that is glued in place.I will probably do a screw down hatch with a gasket so i don't have to use tape.
Unless someone knows a better way to seal the hatch without useing tape?

ridgewalker

Here are some updated pics

ridgewalker

Well i got it painted.Now i will lay down the graphics then clear coat sand repeat till it looks good.

I did not put any strakes on it ,do you think i should or should i try it how it is first?

Where should i mount a water pick up?
I have the kind that attaches to the hull or i could make something if someone points me in the right direction.
I was thinking of useing a brass tube shaped almost like a candy cane and solder it to one of the exit tubes (that is above the stuff tube you can see in the pics above that i made two side by side tubes for water cooling set up)and have it catch the water from the prop spray.Hard to explain but i hope you understand.

Prop size-
I am running a 24t 550 motor, a traxxas evx-2 esc, two ib 4200 mah 6 cell nimh packs=14.4v.
For this electric set up can someone recomend a good starting point for a prop please.

I do have a couple misc props they are-
kyosho d 38 p 1.4
octura Y-534
octura X-431
Will any of those props be good to start with?
What are people who run 12 cell nimh in a wildthing with abrushed motor running?

ridgewalker

I almost forgot to tell.Imade a hatch seal and a simple way to lock the hatch down and best of all it does not leak at all i left it in the tub to test it.I also made a pushrod boot from some fuel tube and another small ring around it to seal it around the pushrod .It works great and made from scrap.
I tapped some alum 3/8 rod i cut in small "logs" and i epoxyed some 3mm screws ti the lip around the hatch.I put the cockpit on tighten the aluminum thingys and seal the hatch.The sealing gasket is weather strip for cars and trucks from the auto store it is about 3/4'' wide and about 3/8'' thick it feels like rubber but compresses it is a bit firm to compress so i superglued it around the inside of the lip leaving about 1/4'' above the lip so when the cockpit is tightend down it doesn't have to compress as much,the pics tell the story better.