two tanks / lean needle

[anthony_marquart]

I finished my sport 12 hydro and have been to the lake with it twice. First I have to commend Gary Findlay on the design. I was expecting the boat to be fairly slow and not really handle very well. I was VERY wrong. I'm running a Picco .12, rear exhaust slightly modified, soliger hardware and 30% fuel.

Here's the probem. The first time out I had only one of two tanks installed. I found the needle setting fairly easily and the boat was absolutley screaming. (The hull blew off the water once and was every bit of 5-6 ft in the air.) (no damage) This time out the boat was every bit as fast as my FF12, I really think it was faster cause it's actually lighter.

THE SECOND day out I had installed the second tank. Now my perfect needle was at least 1 1/2 turns too lean. I think this is related to the amount of pipe pressure and now running through two tanks instead of one. I have the boat running better but not as good as originally. It's still a bit lean and I"M RUNNING OUT OF NEEDLE TO OPEN!. How can I add more pressure or what should I do?

Other than that it's going pretty well. The balance point is almost perfect. With the strut at the correct height, the hull gets airborne and stays very level in flight.

I think I may need a bit longer rudder as I would like more control in the turns.

HELP!

 

[rctinman]

Tony..

Change the brass tubing to 5/32 in the tanks on the line that transfers the fuel between the tanks, and use large fuel line to connect them.

Hope this helps.

Steve Ball

 

[anthony_marquart]

anyone else have any advice?

 

[Don Ferrette]

anyone else have any advice?

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Yup, do exactly what Steve just said. If you make it easier to push the fuel & deliver more volume, which is what the large diameter tubes will do, you won't have to twist the needle out as far to get your flow setting right. B)

 

[Tim_Duggan]

anyone else have any advice?

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Yup, do exactly what Steve just said. If you make it easier to push the fuel & deliver more volume, which is what the large diameter tubes will do, you won't have to twist the needle out as far to get your flow setting right. B)

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You could also choke down the pipe stinger with some K&S tubing to raise the fuel pressure. Just watch for the motor getting too hot - thats the side effect if you go too far.

 

[Don Ferrette]

Not trying to sidetrack the thread but that is a really twisted avatar you got there Tim! :lol: :lol:

 

[Tim_Duggan]

I had it as an animated .gif file on my old PC :lol:

Might have to find something more suitable I think.....

 

[Garry Finlay]

How did that hull balance with all the gear in it? I doesn’t sound like it was too nose heavy.

I’m really happy to hear these hulls work on nitro power too. Biggest difference must just be that the power curve it high with nitro and down at the bottom with volts.

Garry

 

[P THOMAS]

Garry is that hull a round nose and how long is it

 

[Garry Finlay]

That's from the 1/16th round nose plans I drew up for RC Boat Modeler magazine a few years ago. It is 23.5" X 9.5" and 2-1/4 pounds RTR. It is a blast on 6-cells and a 5200KV brushless motor.

Love those old classic round-nose hulls.

Garry

 

[ClayGlover]

how about a pic of the little guy? a "6 cell" round nose going faster than your rigger? awesome

 

[anthony_marquart]

It's not the round nose. It's the atlas van lines or the pay-n-pak model. It's 28 in long.

The balance point ended up about 1.75 behind the ride pads.

Gary, the radio is behind the engine and the fuel tank behind that. I knew I would need to keep the nose down on it so I keep the strut pretty deep.

There are some pics in my gallery. Mainly of the construction I think. The speed may be the mods I made to the engine over the winter... but wow... Can't belive how well it's working.

I've got my second version of the same boat in process now. I have to spread the components out further. It's very difficult to work with right now. It's packed in there very tight,..

Take a look at the pics/.///

how about a pic of the little guy?  a "6 cell" round nose going faster than your rigger?  awesome  

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[Mark Anderson]

"The radio is behind the engine and the fuel tank is behind that." You are simply trying to push the fuel through too much plumbing. Also with the fuel that far back the c.g. will change considerably. By putting the second tank in you increased the weight on the prop a ton which loads the motor more which makes it lean. Idealy you want the fuel as close to the c.g. as possible.

 

[Garry Finlay]

Your right !!! Wrong boat.. The subject of this thread is the 28” pickle-fork Atlas Van Lines type hull. That’s the other set of plans I drew up for RCBM. This has been scaled upfrom 22X11 to 24X12, 26X13 and 28”X14”. RumRunnerHobbies.com is currently offering the 26” X 13” hull in electric trim.

I have a new set of plans submitted that may get published later this year for the 1980 turbine Pay’N Pak in 12th scale electric Limited Sport Hydro.

My avitar is of the little 23" 6-cell classic round-nose. It is all balsa, and can be powered with either a 10-12 turn car motor or 4200 - 5300 KV brushless motor. With a brushless motor, top speed can get into the low 40s. I have a new low profile 16th scale 1969 Karelson U-7 Notre Dame that will get wet this spring.

Sorry for the confusion, Garry

 

[anthony_marquart]

Keep in mind the scale of this boat Mark. Between the pressure line from the pipe, through both tanks and to the carb, there might be 10in of line. Not much really. the fuel tanks are 4.5 in behind the engine. The fuel capacity is only two onces. Adding the second tank only added one once of fuel. Not much difference in weight to the prop, which is about 12in away.

In the next design I will be placing the tank right behind the engine.

"The radio is behind the engine and the fuel tank is behind that." You are simply trying to push the fuel through too much plumbing. Also with the fuel that far back the c.g. will change considerably. By putting the second tank in you increased the weight on the prop a ton which loads the motor more which makes it lean. Idealy you want the fuel as close to the c.g. as possible.

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[Geraghty]

Tony..

Change the brass tubing to 5/32 in the tanks on the line that transfers the fuel between the tanks, and use large fuel line to connect them.

Hope this helps.

Steve Ball

Just like Steve says......Change to 5/32 tubing and your problems will be a memory.

Rod Geraghty

 

[anthony_marquart]

thanks everybody.

I'll get more pics soon. We need more of these little boat around... They are BIG fun and real affordable....

 

[Mike Larson]

Hey guys... Don and all.... do you recommend switching all fuel tubes out to 5/32? for all sizes of motors? ive the same problem on a 45 boat, ( lean, heat) seem to run 21 boats with 1/8 tube and not leanin out..... will the 5/32 help to achieve easier needle setting etc, better on the motors all around? procedure to drill out the rubber stopper and refit bigger lines, then? i run third channels, too, will they still starve without 5/32? i have quite a few boats and switchin out looks a chore.... thanks mike

 

[Don Ferrette]

Hey guys...    Don and all....      do you recommend switching all fuel tubes out to 5/32?    for all sizes of motors?    ive the same problem on a 45 boat, ( lean,  heat)  seem to run 21 boats with 1/8 tube and not leanin out.....    will the 5/32 help to achieve easier needle setting etc,    better on the motors all around?    procedure to drill out the rubber stopper and refit bigger lines, then? i run third channels, too, will they still starve without 5/32?    i have quite a few boats and switchin out looks a chore....      thanks mike

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Mike-

Every boat I run has 5/32" on tank tubes & uses large fuel line, my 21 included. B)

 

[calcraft racer]

Hey guys...    Don and all....      do you recommend switching all fuel tubes out to 5/32?    for all sizes of motors?    ive the same problem on a 45 boat, ( lean,   heat)  seem to run 21 boats with 1/8 tube and not leanin out.....     will the 5/32 help to achieve easier needle setting etc,    better on the motors all around?    procedure to drill out the rubber stopper and refit bigger lines, then? i run third channels, too, will they still starve without 5/32?     i have quite a few boats and switchin out looks a chore....      thanks mike

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Mike-

Every boat I run has 5/32" on tank tubes & uses large fuel line, my 21 included. B)

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BOB VIOLET makes a nice aluminum tank cap and tubes 5/32 w/stopper

http://www.bvmjets.com/ look under accessories/ ducted fan