MAC.84\CF Rigger

[MikeP]

Hi Tim,

I was using the OS 9b with the inflight needle. I am working on setting up an external remote needle. I can use either carb once I get the valve mounted. Do you know where I can get the Fuel Doctor valve and see what one looks like? I am not to happy about the way the valve mounts that has the fuel fittings at 90 deg from each other.

-mikeP

 

[Chris Attebery]

Mike,

I'm using the new CMD mixture controls and they seem to work pretty well. You might want to give them a call and order one.

Tim,

The MACs don't use that much more fuel than any other motor, but because the carbs are so huge the needle has to flow well because there isn't as much draw.

Chris

 

[MikeP]

Chris,

I have a CMD mixture control, it's over a year old. Is there a new one out that is different than my old one?

All I have heard of is a new needle for the .21.

-MikeP

 

[Chris Attebery]

Mike,

I don't think they have changed the design except that the fuel inlet is now soldered in place.

Sounds like you have everything you need to get it running,

Chris

 

[TimD]

Tim,

The MACs don't use that much more fuel than any other motor, but because the carbs are so huge the needle has to flow well because there isn't as much draw.

Chris

Hi Chris,

I agree with you regarding the large bore carb, But mike isn't using it

Mike,

Had an idea after I logged off - I will take my flow meter and measure a friends MAC 84 carb, then compare the readings to my 9b at full flow. That should tell us if the 9B needs drilling out.

I'm using a Kingcraft Fuel Valve (fuel Dr. type) - they are on their website - www.kingcraftrc.com

There are other types of the same thing out there - I think Precisionboats makes one also.

 

[MikeP]

I went to the kingcraft web site and found the valve, I sent an email using the link on the web page but haven't heard back yet. I got the CMD valve and the stock carb installed. I replace the pressure fuel line with large and replaced the pipe pressure fitting with a bigger one. If all goes well I can switch to the 9b at the pond and give it a try. The weather looks like high 60's for Sat.

-MikeP

 

[MikeP]

I got the bugs work out. The stock carb was flawless. Started easy Idles and mills good and on the pipe is killer. Added cup back up to 5.7" from 5.2".

Now I can start tuning the hull. I am going to make new rear sponsons with less attack angle, I was using the spares off the 3.5.

They seem to be kicking the back end up in rough water.

-MikeP

 

[MikeP]

YippyKiYa,

After going throught the whole real of human emotions I got all the bugs worked out and now have a nice reliable boat.

After God sent my CMD parabolic pipe to the bottom of the pond, which I didn't know it at the time was a blessing. I got the new CMD AB .67 pipe set at 12". I also installed a steel braided teather to it.

I finnally got it propped right with a 1667 pitched 5.2" and left the diameter alone. This prop let me richen it up a bunch.

After breaking several turn fin( 3rd boom) supports I made one out of solid aluminum round stock. Added a little more tape to booms 1 and 2.

I replaced the rear sponsons with new ones at 1.5 deg. AOA and got rid of the rear bounce in rough water.

I replaced the rudder servo with a new one with 200 inches or torque.

I ran 4 tanks of fuel(1/2 gallon!) I am totally happy with it, The pipe is sweet, extreamly windy today and the boat just screamed across the waves, it cornered hard and fast. This is the fastest I have ever gone. I left the pond with the same Mcoy mc9 plug I started with still intact.

As soon as the fair weather boaters come out I will get some videos but I have been out alone so far.

Very special thanks for all the info and input from the forum.

http://69.27.9.16/mikep/cf90/84rigger.jpg

-MikeP

 

[Propjockey]

Congrats Mike! Sounds like you're kickin' butt! I guess everybody but me got a boat in the water today. I'm spending the day arguing with some plate aluminum.

(hint--military surplus aluminum is HARD to work with!)

With three boats on the bench and one on the kitchen table, I probably ought to get motivated and put at least one together! The weather's getting really nice.

 

[Ian Inverarity]

Sounds good Mike! ;D

To have such a light boat run so well in rough water is a good achievement! 8)

Any idea of the speeds yet?

Ian.

 

[MikeP]

Ian,

I did have to add some lead to the front to get the balance set. I have also added a bigger battery and a few other things that added weight. I am up to 7.5lbs.

No radar here, when some other boats get in the water with me and the coarse set up I will get and better idea of the speed.

-MikeP

 

[Ian Inverarity]

Mike,

That is still pretty light, about 1 lb lighter than my 90 rigger!!

I look forward to hearing how it goes! 8)

Ian.

 

[MikeP]

Hey I like the way the turn fin looks Mike. I have always thought about making one with a round bend, but I always end up with distinctly straight angles. Let me know how it works.

Hammer

I don't care much for the curved fin, mostly because if you steer left it really lifts the sponson, it holds nice if you are turning hard and fast but pulls down to hard at less that full speed. I can live with it but I think I can do better.

-MikeP

 

[MikeP]

To whom it may concern,

I went through all the links to the pictures and changed them so they work again.

-MikeP

 

[GiantScale]

Thanks for the pic update Mike..

Iv been reading for a few hrs & only 1/2 way through.

Any updates on how she runs?

Can you guesstimate how many hours you have into constuction?

Thanks

Mike

 

[MikeP]

200 hours in 3 months.

On glass water I am guessing high 80's. It's stable in rough water and is alot of fun but is much slower.

-MikeP

 

[GiantScale]

Thats fast Mike!

You dont run rear sponsons?

Can you give me a ballpark figure on material cost? Or what someone might spend building a big rigger like yours only owning a vac pump?

How much weight did you save using CF over wood? Did you first build it in wood to test your design? Is it your design?

And last Question... How do you protect yourself & family from the carbon hazard?

Thanks

 

[MikeP]

Mike,

I run rear sponsons here is a picture of them.

I guess about 250 for material if you are careful.

The weight savings isn't that much over wood. At equal weights I think with CF you have a better hull. R/C boating is a harsh inviroment for plywood.

The design is Hammerheads.

I use a good respirator, I have a dust vacume on my belt sander. I have a fan and use positive pressure to clear the shop.

-MikeP

 

[Ian Inverarity]

Just how bad is carbon? :-

Ian.

 

[MikeP]

Here is the MSDS link.

http://www.2spi.com/catalog/msds/msds11431.html

-MikeP