I have purchased a 26cc CY engine and the tuned pipe attached.

I have lots of questions -

Question 1
With many hull designs available

MAXCAT
OFFSHORE MONO
WILDTHING
WASABI 1300

All scalable designs to make 45-52" inches.

I want to be able to go to the beach and jam around on open water - go to the lakes and if needed there is a small 150m pond for boating that still allows IC boats here in Edinburgh.

What hull would you recommend for these applications - not to sure competition is needed.

Question 2
Water cooling - do I need a pump? Or is the pressure from the pickup enough? I think I need a pump - but not sure.

Question 3
Submerged or surface drive? I don't like the idea of prop walk and think submerged is better - especially if I am in choppy water. Is this correct.

Question 4
I know gearboxes reduce output efficiency but I am curious on thoughts for a dual output counter rotating gearbox to split the power into two props.


This is to be a winter project to commence when I finish my jet boat.
http://www.rcgroups.com/forums/showthread.php?t=1126424

Your lucky day in a way as I've had the same engine and pipe in my Falcon 41 Cat. You're going to like that pipe as it's a nice one for the price. It comes up on the pipe gently, you might be the only one that really notices it as it's that smooth.
1) What kind of hull do you like?
2) No pump needed, my flows water just fine without one.
3) Surface drive. Today's setups don't seem to have propwalk problems. Most propwalk is caused by a poorly prepared prop.
4) Ditch the dual prop idea, really.

For open water you will probably find that the mono hulls are a better option. Have to agree with Ron on points 2-4.
For an idea of what runs well on the open sea have a look at the Omra site.

If you're running a clutch you might want a pump, otherwise you'll be fine. I can't tell from the picture if the engine has one or not.

No clutch - figure it is just more to break - but may look into it in the future.

No club in the UK will allow it to run with that pipe, they are far too noisy.

Thanks for the advice! But I have already ordered a silencer from PCB. Yeah I do not want to piss anyone off with crazy noise, but I think the gas/petrol boat could be fun.

Originally Posted by group11

No club in the UK will allow it to run with that pipe, they are far too noisy.

you dont need to be in a club to run boats,its a free country.
I had one of those pipes,very good power.
Brod..

The pipe can be made quieter very easily as I've done it. It's called an internal stinger which is basically a piece of brass tubing run in through the stinger and goes as far as where the cones meet. A small hole is drilled where the pipe goes in just past the stinger to drain off fuel or water. It can be held in place with JB Weld or a tiny screw tapped into the stinger.

Originally Posted by Ron Olson

The pipe can be made quieter very easily as I've done it. It's called an internal stinger which is basically a piece of brass tubing run in through the stinger and goes as far as where the cones meet. A small hole is drilled where the pipe goes in just past the stinger to drain off fuel or water. It can be held in place with JB Weld or a tiny screw tapped into the stinger.

Do you mean that you slide a smaller pipe inside the stinger. This inserted pipe is basically half the lenght of the entire tuned pipe and gives a direct passage for the pressure to escape from the centre of the expansion chamber. This is could see working as it would not effect either the diffuser cone or the converger cone from operating.

I do have a debate whether or not I need these (money is tight). They are brand new. What do you reckon I could get for them combined ?

The engine, tuned pipe and silencer??

This is an example, just on a much smaller scale.
Money is tight all over. Some places you can save on shipping when combining orders but once on a while you can find package deals.

Thanks for the photo - makes it really clear.

I have already bought the stuff - but now I wish I had the money instead cause I have to insure the car soon.

I paid a total of £280 for everything.

Originally Posted by group11

No club in the UK will allow it to run with that pipe, they are far too noisy.

You can always "dump" the engine cooling water out through the tuned pipe (a wet pipe). This will loose some of the noise but unfortunately also a little of the power as well.
Picture is a RipTide from John Smith with a "Chug-a-Lug" (unknown) 26cc engine and fitted with OPS67 pipe (no baffles but wet piped) which is quiet.
If you go to http://www.modelgasboats.com/Magazin..._Muffled_Pipe/ there is the HendriX article on "How to....". Also some where on that site there is an article on making a Homemade Muffler by Marc LeVac