Custom mono design

[wswatzell]

I am new to RC Boats. I have a Dragon fly 60(photo posted in Photo journal). I have beed playing with a 38" mono design with a ton of help from Ron Olsen. i will post some pics of where it is at now. Any sugections for tweaks would be great!

right now the spesks are

1. 38" long 10 " beam

2. 5" rail spaceing

3. center of engine 30% of length from transom.

4. i plan on using a 7.5 cc nitro with a surface drive

let me know your thoughts & sujestions

thanks

Wade

 

[wswatzell]

this shows the engine compartment

 

[wswatzell]

& this one shows the strakes

 

[Hammerhead]

Is there a reason why the strakes don't go all the way to the back? In Japan, this would be illegal to run in the mono class, If the strakes cut off before the transom and have a 2mm edge they will be considered a hydro.

How about the states?

Hammer

 

[wswatzell]

2mm edge in which way width or height? i have them flared into the hull on 30deg angle so they do not make a step. I went by the IMPBA rulls on strakes that Ron Olsen sent me. if you mean 2mm edge (height from furthest away from hull to the bottom vertically) i am at 2.5mm.

It sounds like it might be illegal Japan, i don't know here in the US. ???

 

[wswatzell]

As far as why i cut the off before the Transom. i have seen this on other designs & by reading a thread on another BB that talked about strakes. they mostly agreed that the center ones arn't needed toward the back 1/2 of the hull. because they can lift the keel out of the water more causing chine walk at high speeds. Also i figure more surface area=more drag. maybe i am wrong in this train of thought. What would you recomend i do with them?

 

[Hammerhead]

That is what I meant!

If it is okay by IMPBA, then you should be good to go. What is the theory on having them cut of so soon, though. I don't realy understand the theory behind them, but all the boats I have seen, have them running all the way to the transom. One exception! AC models are cut off a few inches before the transom but the taper in to the hull. Will yours be like that?

Going to make a mold, or are you going to make it out of wood?

Hammer

 

[wswatzell]

i plan on having a mold CNC cut out of resin board. i work in the mold industry, so i might be able to get it done fairly cheep. & since it would be cut directly from my cad data, it will be excatly what i have got designed! I am not really sure on the theory either, i am just going by what i have read. by the way Hammer i love the out rigger you made. it really looks cool!!!

 

[TomMoorehouse]

wow... that looks great wswatzell. most mono's in the states have the strakes cut off early like that. Have you designed any hook in to the hull? I know a couple of the major players do this. have you seen?

http://www.rcboat.com/cgi-bin/yabb/YaBB.pl...702878;start=10

keep us informed!

 

[wswatzell]

Tom, sorry for a dumb question but i an still new to some of the terms What do you mean by "hook" designed into the hull? after i read the thread you linked, i will hopefull answer your question better. Thanks for the admiration i've a lot of helpful input from Ron Olsen. I will defently keep you updated.

 

[Hammerhead]

If you use polyesther resin when you lay it up, you wont have to worry about designing a hook into the hull, it will get one naturally.

If you look at the bottom of your hull from the side after you pull it out of the mold, you will see a convex line on the keel. This is the hook.

I don't know why, but polyesther based resins seem to shrink when they cure to create this effect.

Hammer.

 

[wswatzell]

oh ok i understand that. i don't have any designed in, but it sounds like i might get it anyways. ;D So what is your overall opnion of the design? i really would like some feedback on that as well. does it look like it might be a fast design?

 

[Hammerhead]

Looks like it will be fast as hell, but I'm no professional on mono design. If you are going by the books, it should run fine. Are you planning to go into production? If you are, you will have to do years of testing, remolding and so-on. If that is what you are up to, then I would recommend doing all the classes from .12 to Xmono at one time. That way, when you are ready to go into business, you will have a whole line up of design tested boats.

Good luck! Hammer

 

[wswatzell]

Hey Hammer that is an interesting idea!!! : That wasn't excatly what i had in mind, but who know what can develope. i was thinking along the lines of building a couple for me & maybe sell a couple to help suport my habbit (hobby) ;D If it is fast enough, maybe i could sell more than just a couple. Mainly though, i just love to design & build things!

 

[jklimpel]

For those who enjoy building as much as racing (like me!), there is nothing more satisfying that creating your own 'monster'...and being a mono-nut (mono boats that is!)....I had to give my $.02.

Your design looks very sound...and ultimately...the speed will be directly proportional to many things.

Do you have a place to run it/them?? Is it more likely to be rough or calm?? Obviously, deeper (V) is better in rough water..although not quite as fast. My personal preference when building scratch built monos is a deep V. So... its a (little) slower....its also way more nimble in rough water...so while the hydro guys are waiting for the wind to die down...you can be having a blast. (and you can always over-power!)

...just my .02

 

[wswatzell]

Jeff. Have you designed any mono's? if you have, i would love to see some pics. Also if you have did you build them out of wood, or fiberglass? I have some questions about that whole process, but i will save that for when i get closer to building one. I do have places to run them. One place is almost always like glass, & another is almost choppy. I have never raced, but i think it would be cool, hence this design. The vee on this one is set at 18deg. I do believe that qualifies it as a deep vee. Thanks for your $.02. Every cent counts! ;D

 

[jklimpel]

Wade;

Over the years, I have scratch built about 8 mono hulls. (2 were scale boat projects)

I still have 2 of the speedboat hulls, and 1 of the scale boats (Remote electric start, Nitro powered, water squirting recovery boat)

A friend of mine has one of my hulls also.

I will post some pics this week. (I may have a few action shots of one of the speedboats from this summer)

Check out the CAD program I linked to in the CAD discussion thread.

It will help alot. You can figure out balance and waterline points etc.

 

[wswatzell]

i down loaded that program last night. i havent had a chance to mess with it yet. ;D do you know if it can read in dxf files. you said that it can write them. i have designed this boat in Cadkey so i can write them, as well as many other type of export files.

that recovery boat sounds cool!!

 

[Mad Max]

As far as hook goes,your going to have wait and see on big gas boats hook is usally sanded off,I've been experimentig with a slight amount of rocker.

The bottom line is a boat mold cut by CNC will be better than anything made by hand,far more acccurate,symetrical and most of all straight.Hand made plugs have ripples,even though slight they still exist,I would cut the mold straight no hook or rocker,make sure the datum points on the mold can be picked up later for mod.s.You can always "bondo" up mistakes and recut without detriment to the end product.

Good luck Max

 

[jklimpel]

Wade;

I am not sure if you can import .dxf files....I have never tried.

Here is a link to one hull I built last winter..(shallow V - terrible in rough water)

http://www.intlwaters.com/yabbse/index.php...ay;threadid=279

..its buried deep in the discussion board.

I will post a few new pics this week.

I build all of my boats with wood. (Fiberglass over wood)