Aeromarine SprintCat Questions

[BradV]

Gents.

I'm progressing the build of a 90 SprintCat with CMB 1.0 and just need a few points clarified if someone can help:

Floatation wise I can't see this thing staying afloat if it takes a dunk. In the past I've found 2 part foam mixes heavy, messy, not neat in apearance and likely to soak up water and fuel.

Normally on a mono I would seal off a bulkhead or two with light ply. However with this hulls layout I can't quite see how that would work.

Any suggestions?

The other matter is I'm not sure the best way to mount the radio box. I want to design something that can be removed easily, but is still rigidly mounted.

One idea was to sit the box on a few pillows of resin to mold it to the hull (ie lube the box so it comes away but leave an imprint). But other than elastic bands to hold it into place I'm out of ideas.

Any suggestions on that would also be greatly appreciated.

Final point. Was is the best epoxy resin you guys know of?

 

[Brian MAhoney]

Brad

Flotation:- In the US they use Pool Noodles (a float for use in swimming pools). I use foam pipe insulation, cut to length and fitted into the sponsons. The Pipe insulation does soak up water and oil over a period of time so replacde each year or so.

Radio Box Mount:- Do you have rails fitted to the sprintcat, if so screw through the radio box and into the rails, seal the screws with a little silicon.

Epoxy Resin:- West systems is about the best you can get.

Brian Mahoney

 

[gil sonsino]

Hi Brad

Insulating pipeline foam is what I've been using on my cats .They are cheap and work great on any model once you can choose from different sizes at any hardware store.By the way they do not soak water and oil as the poodle noodlles due to the higher density..

I only use slow cure epoxy glues because fast set ones aren't water nor fuelproof..There are many good brands at hobby shops just ask for slow set ones.

Personally I like to have removal radioboxes on my boats and the best and cleanerst way I found out is showed in the following pics using Prather fast locks mounted on the rails as you can see.I added a rear bulkhead to hold the rear locks using a sheet of 1/8 fiberglass.

Hope this help you.

 

[gil sonsino]

another of the rear side

 

[BradV]

Thanks Guys, great help indeed and I will go with that.

Is that a bit of foam under the radio box as well gil? Lovely paint job and boat prep by the way..

 

[gil sonsino]

The radio box is just 1/8 up to the botton ...no foam under it Thanks Gill

 

[zagustin]

Hi Brad,

we use the inner tube of a bicycle tire in both sides of the hull. There is no seal off with a bulkhead or foam essential. The inner tube gives the buoyancy you need to avoid going down of the boat . The weight of the inner tubes is to be neglected. Additional advantages are as follows:

The inner tube matches perfectly the shape of the hull.

Easy to maintain and to clean. No soaking impact caused by water or fuel.

Better noise reduction. The magnitude of air pressure gives a variation of volume you need.

Regards

Werner Kraetzer

Germany

 

[zagustin]

Brad,

please have a look to the attached picture, showing my Mean Machine.

Thanx.........Werner

View attachment 3105

 

[BradV]

Thanks Werner, bike tyre probably a bit easier to install as well.

I've a pool needle on its way, will try that first and use the tyre tube aqs a back-up method.

Nice looking rig by the way. What motor is in that?

 

[[email protected]]

Gil,

That's a sweet radio box set up. Great idea how you bolted it down.

That motor your asking about looks like an OS engine.

As for the bicycle tube, doesn't that create a lot of drag when racing it? Looks liek you could have just put it into the side rails and inflated it there, no?

 

[[email protected]]

Brad,

One other way to do it, is take 4 plant hanger hooks (they look like lil gold captain hooks arms) screw them into the back or top of the side rails, now all you need to do is rubber band them down. I add a strip of velcro on the bottom and I'm ready to go. Now the radio box is easy to remove to work on.

 

[Pennywizz6]

As for a radio box heres one that would probably work http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCTC2&P=7 . its off of a nitro hammer and there box is sealed, has all he servo mounts and stuff. Im not sure if it will fit a 1/4 scale, you might want one for your large boat.

O yeah and Gil, you have the prettiest boat ive seen so far. :wub: :wub: :wub:

Phil :huh:

 

[zagustin]

@ Brad: Rodney is right. It is an OS 65 drum valve engine. The setup of the Mean Machine is designed for 65 - 91 OS engines. We convert the OS 91 fan motor to a marine engine. The 91 is a small case engine which is very powerful and reliable.

@ Rodney: The tubes are into the side rails and not outside the hull.

Here comes a picture of the OS 91 "VR-M". BTW John Ackerman did a similar conversion work.

Regards

Werner

View attachment 3106

 

[gil sonsino]

Thanks Phil for your comment on my boat.

Actually is a retired boat once I've only ran saw riggers now and my son very often play with it.

Gill