faceplantjae

Hello, My name is Jason and I am new to this website and to the r/c boat hobby. My wife stated I needed to get a hobby and I have wanted to do this for years. Little did she know it will cost a lot more than she thinks.... With that said, I am building a Dumas Miss Circus Circus. I have read old threads on here for the last two weeks trying to find my answers, and there are many knowledgeable members on here. But, I could not find the needed answers. So I apologize for my ignorance on the hobby and for any redundant questions.

I am building the Dumas Miss Circus Circus. I have read that the Dumas materials are crap and have ordered some aircraft grade ply from some members recommended sites. I hope all supplies will be delivered within the next couple of weeks. I want to do this boat the right way and have a budget of $2000. In the mean time, I need know some suggestions for my questions.

1) What size engine can this boat take? I have done some research and it looks like the MAC's are a good way to go.
2) What is a good servo box?
3) What is a good servo and remote brand?
4) How do you know which way the prop spins before you get the engine? And does it matter which way it spins?
5) Is it a good idea to fiberglass and seal every part of the boat during construction?
6) When is a good time to cut the lightening holes in the framing? After the bottom sheeting is on?
7) Is the Newton paint scheme page worth the $35? Does it actually give the measurements of the paint stripes and angles?

Thanks a lot for any input that can be given. I am sure I will have tons of questions during the build. I hope to get started in a couple of weeks and will start a thread or blog to show my progress.
Have a good one,
Jason

Hydro Junkie

I like it, someone that is asking the questions before starting the build. Before I start to answer your questions, I need to ask what kind of ply and how thick is what you ordered. Not all ply is made the same so, if you ordered aircraft grade LITE PLY, you wasted your money. One other thing you need to be aware of is that the Dumas Circus is a morphing of two boats, the 1984 Atlas and the 1987 Miller High Life, so it's not a true scale boat. That being said, on to your questions
1) MACs WERE good, now they are hard to get and, if you do find one, they are hard to get parts for. The hot engine today is the CMB .67 greenhead. They are easy to get parts for and are a good fit for a hydroplane due to the power and RPM levels they can produce.
2) I'm assuming you are talking radio box. This is more up to the builder than anything else. The requirements are the ability to hold all of your radio gear, be solidly mounted to or integrated in the hull and be virtually water tight. They also need to be sturdy enough to handle the stress of the servos acting on the rudder and throttle without cracking or being dislodged
3) This is personnal choise more than anything, kind of like the Ford/Chevy/Mopar deal. You will need a minimum of a two channel radio with one servo that is rated at no less than 90 oz-in for the rudder. I use the Futaba S3305 for my boats rudder as it puts out over 90 in-oz of torque, has a standard size case, metal gears and ball bearings rather than bushings for reliablity
4) Looking at the back of the boat, all current engines will turn the prop counterclockwise unless modified
5) Seal-yes, fiberglass-no. The wood can be sealed with several different products, I use West Systems epoxy for both assembly AND sealing. It's water and fuel proof(very important) and will strengthen the wood. Adding fiberglass, while adding some strength, will add a lot of unwanted weight that will seriously degrade your boats performance. I know that the instructions say to use fiberglass on the bottom, I've personnaly never seen a properly built boat that needed it
6) This really depends on two things, are you using the kit supplied framing materials or replacing it with better and what do you have for tools. I cut lightening holes out of a Dumas Pay'N Pak kit I'm building using the supplied materials before assembly and it's been like dealing with eggs, the material is that weak. If you're using the supplied materials, cut after assembled and stabilized IF you have a good rotary tool(such as a Dremel). Be sure to leave a good amount of material around the edges of the frames or your boat will crumble. If you're building from aircraft ply, it's your choise.
7) The Newton plans are a very good reference and, in my opinion, are worth the cost. You will need to decide which paint scheme you like, the Miller High Life or the Circus. If you were to change the sponsons, you could also build the American Spirit. The plan set you would be most likely to use would be set 146.

I've been doing a couple of build threads on two smaller Dumas boats, one the previously mentioned Pak, the other a remanufactured and modified version. These two build threads may answer some of your questions as well since I tried to keep them easily understandable. If you're interested, here are the links to the threads:
Kit build, only modification was a different bottom profile http://www.rcuniverse.com/forum/m_10351409/tm.htm
Remanufactured kit http://www.rcuniverse.com/forum/m_10666178/tm.htm

Just so you know, I also have a Dumas Circus kit that I haven't started so if you have questions after going through the two build threads, let me know

faceplantjae

Hello hydro junkie. Thanks so much for all your info. I have read many of your posts on this site while doing research and have learned a lot. To start off. I purchased all birch ply from national balsa. The thickness is per what one of your old threads stated. (1/4 for the transoms, 1/8 for the framing, and 1/16 for the sheeting). If I remember correctly, the total cost was about $200. I did not know that the design was becoming a morph of the two boats. I guess I can save the Dumas kit to make a Miller later on, for I am wanting to do the Miss Circus Circus.
I will look into the CMB motors. Knowing that I am new to the hobby, I need to be able to find parts easily. Do you think that this boat can take a bigger motor such as a .87 or should I stick with the .67? As for the tools that I have available. I have countless hand tools, a dremel, and a sander. The only thing I do not have is a scroll saw. And do you know if the Newton plans have to paint measurements on them?

Thanks again for all your help, i am sure i will have namy other questions. I will check out your other threads when i get off work. And I will definitely post pics when i get started.

Have a good one
Jason

Hydro Junkie

Okay, you pretty well matched what the kit has for ply thickness's so it's all good. You could also replace many of the cross frames with 1/16" ply if desired to lighten the framework.

As for the engine, stick with the .67 as going larger will most likely overpower the boat. Overpowering the boat can make it want to fly. While some lift is desirable, wanting to fly means a damaged boat at best and a wrecked boat at worst.

Dumas is cutting back on boat kits being produced so you will want to order a second cowl if you're going to build a second boat. The reason for this is the Dumas scale boats have a narrower engine bay than the available cowls that can be obtained elsewhere so, unless you want to modify the hull, no other cowl will fit.

The Newton color sheet has the layout drawn to scale, FOR THE MOST PART. You will not be able to use the plan sheets as a direct pattern to make the deck but it gives all the information you will need to paint the boat. There are several sources for the correct color numbers for the boat as well.

As far as tools, not having a scroll saw isn't a big deal. It will make the cutting out of parts slower but other than that.......................................

faceplantjae

Thanks again for all your information. It is very helpful. I should begin construction is about two weeks. And will let you know how things are going.

8thScaleRoostertail

Hey Jason,
Welcome to the wonderful sport / hobby of scale hydroplanes. I too recently made the plunge after 20 some years or following the sport. HJknows his stuff well and has a lot of experiene with Dumas kits and scale hydros. I also have the Circus kit but have not started it yet. Another avenue you may look at is the recent move to laser cut kits. There is a guy out in NC who has started laster cutting scale hydros. He does great work and has a bunch of boats to choose from. Check out his thread on intlwaters below. I recently puchased the 8701 kit from him to make either the 91 or 94 Miss Budwieser (I have not decided which yet. He uses quality wood. They are just the frames. You need to skin the boats yourself. However, he is also beginning to offer some kits with skins. He is working on the Bud T6 kit with skins now, I believe. RCBoatcompany supplied me with the cowl and wings. I'm hoping to build both the Circus and the Bud over the winter. I'll be asking HJmore questions as the builds progress. Thanks



http://www.intlwaters.com/index.php?showtopic=43524

Hydro Junkie

I'd build from plans rather than buying one of his kits. If you want to make any changes in any kit build, you have to remake the parts affected anyway so why have to pay for them twice? That's my thoughts on that anyway

faceplantjae

Hello 8th scale. I have researched the hobby for about a month before I decided to plung into it. And I am having a blast so far. I have learned many things. And yes hydro has helped me in this post as well as a lot of his old threads. I have heard about the laser cut kits. But I still needed to purchase the skins and the cowl. So I opted to use the Dumas kit as a template for mine. I have decided that I will first trace the Dumas kit and build it for my wife. My reason for that is that if I mess up, then it is on hers and not mine.... Plus she might like it and let me spend more time in the garage and spend more money . Lol... But thank you for the referral, I might look them up when I complete these two I have now. And Hydro, I am going to make one the Miss Circus Circus, and the other one the Miller... Got some more stuff in. Hopefully next week it will all be here and I can get started. I am going to pat pictures and construction issues for others to see. What do you think is the best way to go about it? Start another thread, do it on this one, or do a blog? Thanks.

Hydro Junkie

I would do a build thread in the Nitro Forum. The reason for this is that the thread will be focused on your build and not what was discussed in this one. That is the reason I have two build threads going at the same time, one for a kit build and the other for a remanufactured and modified build, to prevent confusion. When you start the build thread, I have a few things to say BEFORE you start cutting wood that will help you build a better boat, just a heads up

faceplantjae

ok, I will do a build thread when I am ready to start. I will let you know and post the link so you can tell me about the things to do before I start. I do have a couple more questions though.

1) If I go with the CMB .67, will any engine mount work?
2) Is a turn fin necessary?
3) I hear good things and bad things about an auto bailor. Should I use one? Or should I make a suction bailor? Of course I hope to not have any leaks in my boat to begin with.....
4) It is coming into Christas shopping time, and Iam sure my wife is going to cut into my boat money for gifts. My question is this... Do I need to have the engine mounted with all the servos and gear, and rudder assembly in order to complete the wood build part of the boat?

Thanks again for all the great help.

Hydro Junkie

And I have some answers for you:
1) NO. Dumas has an odd sized engine bay so not all engine mounts will work. If you have to tools, you may be money ahead to make something yourself.
2) Only if you want the boat to turn. The turn fin holds the front of the boat in the turn and is actually a pivot point the boat revolves around. Not having a turn fin will cause the boat to slide sideways rather than turn
3) An auto bailer is not needed. Just drill a drain hole in the back of both sponsons and each side of the transom for the area under the deck. Cover with monokote or similar and run it
4) No, but having all the parts that are affected by hardware that is under the deck fitted before the deck goes on will make your build go smoother.

faceplantjae

Hello,
I will get my wood from National Balsa on Tuesday, and the Dumas kit on Wed. Hopefully, I can get to Home Depot to get the wood for the building jig before next Thursday. I just have to get the plans to see what I need.

I went to the Dumas website but the engine holes are not listed for the CMB 67. Is the mounting pattern the same as K&B 67, Rossi, OS max, OPS or Picco? Other websites state that the kit description says is to get a 4" engine mount. And are there any suggestions on what brand or place to get a turn fin? I see that there are many different designs and mounting configurations. But, the mounting technique and configuration can be discussed later, Because I don't want to get ahead of myself.

Hydro Junkie

The first thing I will say is if you haven't ordered the Dumas hardware kit, don't. There are multiple places you can get quality hardware for your boat:
http://rossisales.com/ for Speedmaster
http://www.aeromarinerc.com/ for Aeromarine
http://www.rcboatcompany.com/ScaleHulls.html for Accu-Tech
http://www.CMDRACING.COM
There are more, figured this would get you started.

Hydro Junkie

Just went and dug out the instruction sheets for the Circus. You really have a few options available as far as engine mounts go. The instructions show a Steve Muck engine mount bolted through spacers and the engine bay walls. While this works, you do have other options as well.
1) bolt four "Humdinger" rubber vibration dampers through the boat's bottom and through a pair of .091" aluminum plates. Drill and tap the plates to fit your motor and you're done
2) Buy an Octura extruded 4" mount and install it in the engine bay. There are several sizes and styles so you can pretty much install it as you desire
3) Install wood blocks and bolt plates to them like in option 1 instead of using the ruber dampers

I'll be doing option 1 for my boat, with a twist. Since I have a Sherline minimill, I'll be machining engine mounts using the Humdinger isolators. My reason for doing this is the isolators reduce engine vibration being transmitted to the hull. The vibration will increase noise while running as well as increase the possibility of seams failing due to the vibration

faceplantjae

Thanks for the info. I did not buy the Dumas hardware kit. I didn't because I remember you and others saying that it was junk and outdated. I have been looking at all the different hardware and can't see what distance from the transom the rudder should be?Is this personal preference or is there a set distance for 1/8th scale hyrdos?

Hydro Junkie

The distance from the transom to the rudder is mostly personnal preference but, at the same time, there are some things to consider. The first is how long do you want your pushrod to be. Longer rods tend to bend more than a short one. This is why I put the rudder on the left side of the prop, so that the rudder is pulled into the dominant turn, that being to the right. The other is how tight do you want to be able to turn? A longer rudder bracket makes the boat behave like it's that much longer and has a wider turning radius than a boat using a shorter bracket or being shorter in general . That being said, you can tighten up the turn to a point by adjusting how far you pull the rudder using the servo. On all my boats, I have the shortest rudder assembly I could get, in my case from Speedmaster

faceplantjae

Thanks again. I bet you are getting tired of all my questions.  I was looking at installing my rudder on the left transom as well. But it seems to be the opposite of what a lot of people do. Also, I was thinking 2.25 inches off the transom would be ok for me. Or should I go shorter? Here are some more questions.

1) What about the tapered or the straight rudders? Is there a difference and is there a better performing one of a hydro?
2) What about length of the rudder. I see them ranging from four inches to a little over five inches. Any suggestions on this?
3) Are the holes on the CMB 67 engine a certain distance? Because it is impossible to find a 4" engine mount for the CMB 67. I was looking at the CMDi motor mounting system for their 67 and it looks like it would work, but I don't know if the rail distance for that mount is for a 5 inch or 4 inch.

Hydro Junkie

As I said in my last post, this is all personnal preference. As far as rudder length and blade shape, you will need to test and test to find out what works best as no two boats are the same. The CMDi engine mounts look like they are designed to go through the engine rails or tub sides in vee or rigger hulls and may not be the best for a scale boat where you won't have access to under the deck. Your best bet would be to contact the various parts manufacturers and see what they can do for you. In my case, I have started making some of my own parts when it's a "one-off' type of deal

faceplantjae

Ok I got my kit and my wood from National Balsa today. But, unfortunately the box for my wood was waterlogged and all the wood was warped. I called National Balsa and they said they would file a claim with UPS, but who knows how long this will take. So, I guess my build is delayed again. Guess I can build the jig tomorrow. I will post the link to the build thread tomorrow. That way Hydro can post his Suggestions for cutting the wood.

Hope everyone has a great Thanksgiving.

Hydro Junkie

Cut it in what way? Are you talking abou thow to lay out the parts or are you talking about the actual physical cutting?

faceplantjae

Hello Hydro. I was referring to post #9. You stated you had some tips for cutting the wood to make a better boat. Well, here is the link to the build thread.
Thanks again

www.rcuniverse.com/forum/m_10828546/anchors_10828546/mpage_1/key_/anchor/tm.htm#10828546

Hydro Junkie

Okay, I got what you're saying. As soon as your order comes in, I'll give you a couple suggestions in the other thread[8D]

faceplantjae

Well, I finally had the chance to get on the website. Here is some pics of how my National Balsa order came in. Still waiting for new order to arrive.

faceplantjae

Hello all. I have decided to go with accu-tech hardware (strut, turn fin, and rudder). Is this a decent brand of hardware? And my other question is where can I get an octura extruded motor mount? I have looked everywhere. I can't even find a pic. Maybe I am dumb....

Hydro Junkie

Nothing wrong with Accutech considering several of the boats here in Washington state have it installed and race routinely.
As for the Octura mounts, you can check here:
http://www.hobbyhouseinc.com/index.p...sort=2a&page=1