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'Wild Thing' Construction Pictures - 12/7/2004 2:20:44 PM   
Macleod



Posts: 315
Joined: 3/26/2004
From: Perth W.A, AUSTRALIA
Status: offline 		I thought I would start a Construction Thread, where myself and others can post their progress and pics.....

I've just started building the hull and have made the engine mounts of of alum.

Any advice would be greatly recieved from those who have built the boat....Thanks to those who have given me lots of help already...

Will keep you all posted.....if interested......

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Ross
Decerto Racing....There can be only one....
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RE: 'Wild Thing' Construction Pictures - 12/7/2004 9:25:25 PM   
John Palica


 

Posts: 1228
Joined: 5/22/2003
From: Vernon, CT, USA
Status: offline 		Keep the pictures coming. If I see something that looks wrong, I'll bring it to your attention. Looks like you are on the right track so far. What is the engine mount rail spacing? Remember, if you plan to put in a main tank at the CG and a hopper in front of the engine you will want to leave enough room for a tank between the mount rails and the side of the boat. Mine has a 3" rail spacing and I barely had room for a 6 OZ sullivan oval tank. That is slow cure epoxy you are using! This is no place to cut corners and use 5 minute stuff. The 5 minute or any fast set epoxy for that matter, never gets a chance to soak into the wood before it cures. It may be OK in balsa construction where the wood is porous but stick to slow set where hard wood is involved. I like to use West Systems epoxy. It's a real slow set. I usually let it set for 24 hours. Also - lay some glass cloth in to reinforce the joint between the engine mount rails and the bottom skin after you have installed the mount rails. Run the cloth from the radio box bulkhead to the bulkhead in front of the engine. Both sides of the mount rails.

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(in reply to Macleod)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 12:04:46 AM   
CFRACR


 

Posts: 180
Joined: 10/30/2004
From: SARASOTA, FL, USA
Status: offline 		Good advice John!

(in reply to John Palica)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 5:10:14 AM   
ejp67


 

Posts: 821
Joined: 7/29/2004
From: Private, USA
Status: offline 		I'll be sure to post some pics also once I start building.

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RE: 'Wild Thing' Construction Pictures - 12/8/2004 11:02:06 AM   
Macleod



Posts: 315
Joined: 3/26/2004
From: Perth W.A, AUSTRALIA
Status: offline 		John, the engine spacing is 4 inches. My tuned pipe will be exiting centre of the transom (see pic). Will use centre main tank with hopper on side to counter-balance torque roll, perhaps.....Why did you put yours to one side, as you got centre pipe also???

I will be using slow set epoxy and woven glass for the reinforcement. I have lots of experience in the glassfibre industry.....

What C.G percentage did you use....Is it 33% ???? My hull is 30 in by 9 1/2 in.

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Ross
Decerto Racing....There can be only one....

(in reply to John Palica)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 12:08:49 PM   
CMB RS35


 

Posts: 46
Joined: 5/11/2004
From: London, UNITED KINGDOM
Status: offline 		Macleod,

You will probably find the Tunepipe length is far to long routing it like that. On a .21 a start off ballpark figure is around 200-220mm. My CMB21LS is running a pipe at 185mm

(in reply to Macleod)
       Post #: 6

RE: 'Wild Thing' Construction Pictures - 12/8/2004 2:07:55 PM   
John Palica


 

Posts: 1228
Joined: 5/22/2003
From: Vernon, CT, USA
Status: offline 		Ross, I believe I mentioned this to you in the past. YOUR TUNED PIPE CONNECTION IS MUCH TO LONG!! You can't just stick a pipe anywhere in the exhaust circuit and get any added performance from it. It has to be tuned to the exhaust/intake cycle and for best performance, the engine should be timed for a pipe. A tuned pipe works by creating a reverse pressure wave back to the engine at the precise time that the incoming fuel charge starts to exit the exhaust port (on a pipe timed engine, the exhaust remains open for a short period after the intake closes). The returning pressure wave from the pipe pushes the fresh fuel charge back into the combustion chamber thereby "super charging the engine". As MCH01 indicated, each engine, depending on the way the exhaust and intake ports are timed, has a specific ideal exhaust length to the wide part of the pipe. It will also vary depending on the volume and style of the pipe. On my MAC .21 I run a MAC Products .21 unmuffled pipe at 9 1/4" (about 235 MM), cylinder center line to the pipe wide point. Believe me, the engine is very happy!

I put the large tank in my boat on the side because it's closest to the CG and being the heaviest tank in the boat, has the greatest affect on CG as the fuel is consumed. That places the hopper tank as close to the carb as possible giving me uniform fuel flow. The impact on tracking due to the larger tank on the side is negligable and is controlled by the trim tabs. AS far as CG location, it's where John Finch recommends in his build instructions. Exact distance from the transom is a government secret. Actually I'm at work and the boat is not with me today so I can't get you a measurement right now.

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John

(in reply to Macleod)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 2:16:21 PM   
John Palica


 

Posts: 1228
Joined: 5/22/2003
From: Vernon, CT, USA
Status: offline 		Ross, sorry if I came off a little strong. I've signed on to help you build a good running boat so I'm going to be pretty blunt at times. Ask my son. He had a battery problem in his car and I told him to go to one of the discount auto parts stores and pick up a new original equipment size battery. They might even install it for free. If not I would. He went to a repair shop and they raped him with a $100 bill for an installed new battery that would have cost him $30 if he listened to me. You can add your own words for my reaction.

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John

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RE: 'Wild Thing' Construction Pictures - 12/8/2004 3:49:12 PM   
Macleod



Posts: 315
Joined: 3/26/2004
From: Perth W.A, AUSTRALIA
Status: offline 		John, the photos of the engine and pipe is not the finished length. I just put the pipe and engine together to show all what type of gear I am using. I have done an extreme amount of research (About 300 mb of data) into everything involved in the running and setup of the mono hull I am building. But it all still comes down to what others have done and found things that may or may not work, In asking these questions I save myself time finding out the mistake for myself....I listen to all comments and be as blunt as you want, in the end,its my choices of what I choose to do when I build it (if I do wrong , I swim), Dont get me wrong I value all of everyones help....I just want to do it right the first time.

I really enjoy making things and I cant wait to get the hull on the water....

Hope I didnt offend anyone..SORRY

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Ross
Decerto Racing....There can be only one....

(in reply to John Palica)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 5:52:41 PM   
Ron Olson



Posts: 13204
Joined: 5/10/2002
From: Kalamazoo, MI, USA
Status: offline 		You did make a good choice with the CMB TT pipe. One of the guys that I know had one on his CMB Greenhead powered Wild Thing and that boat is so quiet that you can hear the water splashing off the hull!
John reminds me of another boater that I've met, good intentions but comes off as a grump sometimes. He's only helping you trying to make sure that you do it right the first time.
Offsetting the pipe to where it should be makes it easier to start as it won't be in the way of the starter belt. My buddy modified his radio box so that it is offset to the right as far as the lid goes and on the left, put in an angled piece of ply to get his pipe lower in the hull. There is still room under it for a battery pack or reciever.

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Member, Southwest Michigan Model Boat Club.

(in reply to Macleod)
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RE: 'Wild Thing' Construction Pictures - 12/8/2004 9:21:54 PM   
John Palica


 

Posts: 1228
Joined: 5/22/2003
From: Vernon, CT, USA
Status: offline 		Here's an example of what Ron is talking about with the pipe installation on my boat. The battery and receiver are tucked in under the pipe channel. The starting belt loops over the engine and gets trapped in place by the cooling plumbing once the engine is started.

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< Message edited by John Palica -- 12/8/2004 9:27:05 PM >

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John

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RE: 'Wild Thing' Construction Pictures - 12/9/2004 5:22:11 AM   
Ron Olson



Posts: 13204
Joined: 5/10/2002
From: Kalamazoo, MI, USA
Status: offline 		Nice set up John! Here's the way that Mike built mine for side/rear exhaust motors for my .12 sized version:

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RE: 'Wild Thing' Construction Pictures - 12/9/2004 12:24:05 PM   
Macleod



Posts: 315
Joined: 3/26/2004
From: Perth W.A, AUSTRALIA
Status: offline 		So looking at my engine and pipe what do you both recommend, 1. Centre pipe or 2. side pipe.....????

Hope to use centre tank right close to engine and hopper to the side of the carby.....

_____________________________

Ross
Decerto Racing....There can be only one....

(in reply to John Palica)
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RE: 'Wild Thing' Construction Pictures - 12/9/2004 1:14:44 PM   
Ron Olson



Posts: 13204
Joined: 5/10/2002
From: Kalamazoo, MI, USA
Status: offline 		The biggest problem that I see is the header being bent downwards, I'd see about getting another one if possible. I think that it may give you more trouble later on.

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Member, Southwest Michigan Model Boat Club.

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RE: 'Wild Thing' Construction Pictures - 12/9/2004 2:23:44 PM   
ejp67