Some questions on running gear. (long)

[BigManBrock07]

Ok, I've been doin' the RC Boat thing for a few years and love it. I had a nice hydroplane but had to sell it unfortionatly. :(

But now I want to get back into it with a Deep-V hull (or Big Cat). Now for the questions.

I have 3 motors to choose from. A .40 Nitro air-cooled motor, a McCulloh chain saw motor w/clutch, and 31cc Craftsman weedeater motor, again, air cooled.

I want to be able to convert any motor I use in the boat as well as run a transmission I plan on making. I'm a student Mechanical Engineer so I have access to any and all tools needed and I've almost finished the design for it.

The tranny will have a single input and dual outputs with a reverse rotation to help with the steering problems of a single prop.

Also it will have a reverse gear. Now I know this tranny will slow the boat down some and speed isn't the biggest thing here for me on this boat. My tunnel hull was clocked at 47mph and I love the speed, but I want a realistic model now.

I will do this as a project next semester but am researching it some now to get a head start. I'd love any help or suggestions ya'll have for me. Also it will be dual rudders.

One more thing....is there anyone out there with any deep-v or big cat hull designs for anything from approximently 29"-45" boats.

Thanks so much just for taking the time to read this, and a reply would be very helpful. :D

[bufferoo]

This sounds like a great project! One question that comes to mind is the prop selection. With the size of prop that you will need for these engines, have you checked into the availability of both right AND left hand props? It would really sour a project to go through all that work only to find out that you can only get the LH props you need.

Also, if you are going with gears, do you think that they could hold up to the high speed of the nitro motor? Maybe one of the gassers would be your better choice?

Just a couple of thoughts.

Bufferoo

[BigManBrock07]

Thanks Bufferoo, I plan on using aluminum or steel gears and keeping it sealed so I can lube it. Again, I know that will slow it down some, but it will help in dependabilty.

As for the props, I'm actually not sure what I will need to run. Any suggestions on what size as I will have 2 props for one motor. :confused:

I know they will need to be a little smaller than the normal overall outer diameter and pitch, but I reall have no clue. Also I think a 2 blade will do fine, what do ya'll think? DD, I've read a lot of your stuff on props, do you have any suggestions?

On the LH and RH go, if for some reason I can't find matching props like I want I will just have to make them turn the same way. Although I'm really hopin' someone has a metal matching prop set for my app.

Thanks, Philip Brock

[Pagemaster]

We have some L & R carbon Fiber props up to 70mm

Steven Vaccaro

[Doubledog]

I agree with what the othes have said... It does indeed sound like a fun project! WAY over my head though.

I like what Steven said about the carbon props for a good starting point. If you choose to go another route, then theres always Prop Shop Props out of England. Pricey not doubt but some wonderful props. (lost the link or I'd post it for you)


Here's one of my buddy's boats with the carbon props. They can handle some power as long as the speed stays sub-sonic. lol.

[BigManBrock07]

Double Dog, where can I get a set of those outdrives...I was gonna look at makin' a set of those too because I've never seen a set for nitro...but they look sweet. :eek: PLEASE....give me something on those....I'd be in heaven. Thanks, Phil :D

[Doubledog]

The Doc is importing them from www.MHZUSA.com. When you contact him, tell him DD sent you. We've done business in the past and is a good guy.

btw, I'm in Germany and see MHZ products everytime I run. Expensive but excellent quality.

[Ron Olson]

Forget the .40 engine if you haven't already. Air cooling means that it probably came from a plane. Hard to cool and the timing is terrible for a boat. Not huch in the way of HP and RPM either. I think that the Mac engine from the chain saws has reverse rotation so if you use that one, keep that in mind. The Craftsman might be your best bet.

[BigManBrock07]

Ron, any chance you can give me any info on who makes that motor, or if there is a water cooled head for it. Thanks...Phil

[Ron Olson]

On the Craftsman? Some were Homelite's. They may have used Robin's, Echo's or some other brand also. Homelite water-cooled heads are easy to find, the other brand names are a little tougher to find them if not made at all.
For the hulls, one good source is: http://aeromarinerc.com/
Marine Specialties has a lot of parts for what you want to do also, I don't have their web site handy, do a search for it.
Seeing how that you are in Melbourne, FL, try Brian Watts at www.rocketcityracing.com . Real nice person that has a lot of Gas boats plus hardware.

[BigManBrock07]

Ok, at the moment I can't afford over 200 for a hull, so is there any chance someone has plans for one, or a site to point me in the right direction. Now granted this will be the first hull I've built, but with decent directions and you folks, I'm sure I'll make it happen....right? :p

Seriously though guys, please. :D

Phil

[Hydro Junkie]

Why not design your own? As long as you don't exceed a four to one length to width ratio, you shouldn't have too many problems. Just keep the bottom with a Vee in it and go from there. Who knows, you might end up with the slickest boat in town. :)

[BigManBrock07]

I think I could design it...I just don't know how to mold it and all....what to use to drap the fiberglass over....or should I use a wood frame and then glass that. Should I use something else and just use a good glass and then take it off the mold or what? I'm not looking for anything fancy....but I do want to make it decent so it won't break.

Thanks for all the help so far guys. :)

[Hydro Junkie]

There are a couple of ways to do a fiberglass hull. Option one is to make a plug and lay the glass on the outside of it. While this will make a floating hull, it wouldn't have the fine finish of a female mold. Option two is to make a plug and cover it with fiberglass. Make sure the glass and resin is good and thick, as this will be the mold. After you remove the plug, go over the inside of the mold carefully. Any air bubbles in the mold will show up on the molded hull coming out of it :( After you get the mold ready, coat it with a release agent, followed by gelcoat, followed by layers of glass and resin. When the resin has hardenned, remove the hull from the mold, do whatever touchups are needed, and your done. You will need to make a mold for the deck as well. This was a quick and dirty explanation. I'm sure there are others out there that know much more than I about working with fiberglass. One thing you will need to be sure of is that both sides of the plug are identical. If not, it will be very difficult to get the boat to run properly. Good Luck :)

[BoatDoc]

if you're interested in molding your own fiberglass hulls, check out this website. they have free on-line brochures that show the molding process and they also sell everything you need to lay up a mold. there is an entire section dedicated to beginners to help out and make your first project go a little easier.

http://www.fibreglast.com/

[Hydro Junkie]

I wish I had known about that site before today :( Went to a race and started picking brains about resins and plug materials, etc. Only one person REALLY knew how to work with glass. Looks like I have some studying to do ;)