Go Back  RCU Forums > RC Airplanes > Beginners
 2 or 3 Line Fuel Tank Set Up >

2 or 3 Line Fuel Tank Set Up

Notices
Beginners Beginners in RC start here for help.

2 or 3 Line Fuel Tank Set Up

Old 06-06-2008, 09:45 AM
  #1  
Senior Member
Thread Starter
 
Warbird Joe's Avatar
 
Join Date: Jan 2007
Location: Hamilton, OH
Posts: 1,029
Likes: 0
Received 0 Likes on 0 Posts
Default 2 or 3 Line Fuel Tank Set Up

Hello all. Well I have decided to buy another plane. I bought the BH T-28 Trojan and Magnum 91 2 stroke. It is supposed to be here saturday 6-7-08. Come on Fed Ex. Any hoots, this is going to be my first cowled airplane and I am not sure if I have should do a 2 or 3 line fuel tank set up. Also, Minn or RcKen if you would post a diagram of a 3 line set up I would greatly appreciate it. Thanks and look forward to everyones humble opinion.
Old 06-06-2008, 10:10 AM
  #2  
 
Join Date: Aug 2007
Location: Pittsfield, MA
Posts: 1,610
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

Below is the graph that RCKen posted, I believe that is what you are looking for.

Or you could use one of these fueling systems
http://www3.towerhobbies.com/cgi-bin...?&I=LXD745&P=7
Attached Thumbnails Click image for larger version

Name:	Yw68762.jpg
Views:	3088
Size:	24.3 KB
ID:	964850  
Old 06-06-2008, 10:20 AM
  #3  
Senior Member
 
r2champion's Avatar
 
Join Date: Sep 2006
Location: Mayking, KY
Posts: 497
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

I highly recommend using the 3 line system with a fuel dot for cowls. Anything that you add extra will be potential for airleaks. Keep it simple, and avoid having to chase down potential tuning problems later.
Old 06-06-2008, 10:35 AM
  #4  
 
opjose's Avatar
 
Join Date: Nov 2005
Location: Poolesville, MD
Posts: 12,624
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up






This is even simpler, requires NO fuel dot, uses only two lines and has the advantage of letting you perform pinch tests on your cowled engines.

It basically brings the fuel line out of the cowl, so you can fuel/defuel and perform pinch tests.

Old 06-06-2008, 10:38 AM
  #5  
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,517
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

The picture of the 3 line tank plumbing has 3 labels for the lines.

The top label says VENT. Most glow engines nowadays run best with muffler pressure. This line is very often connected to the pressure tap on your muffler. When you fuel the airplane using the line labeled Fuel Dot, you discover that the tank is full when fuel overflows out that VENT line, wherever it goes. If it can quickly and easily get out of the muffler, you have no problems seeing that the tank is full just as soon as it is full. If the muffler layout doesn't do that, many people put a T in the vent line and run the extra line to wherever the Fuel Dot line goes. They have two lines sticking out somewhere and both are plugged. The attached picture shows how I do most of my airplanes.

The two lines are pushed into the cowl in the picture. That's how they are except when fueling. Pull them both out and remove the plugs to fuel. Into the front one that goes where the Fuel Dot line in RCKens picture goes, and when full, you'll see overflow out the rear one.

works like a charm

The T's available at most LHSs are absolutely adequate and dependable with today's excellent silicon fuel tubing.

The plugs are sold in packs of two. They do what Fuel Dots do. There is really little difference in function or reliability. Both the plugs and dots are as reliable as your ability to stick a plug into a hose.
Attached Thumbnails Click image for larger version

Name:	Ki20307.jpg
Views:	873
Size:	106.8 KB
ID:	964853  
Old 06-07-2008, 08:54 AM
  #6  
Senior Member
Thread Starter
 
Warbird Joe's Avatar
 
Join Date: Jan 2007
Location: Hamilton, OH
Posts: 1,029
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up


ORIGINAL: shd3920

Below is the graph that RCKen posted, I believe that is what you are looking for.
Thanks SHD3920, that is exactly what I was needing.


The picture of the 3 line tank plumbing has 3 labels for the lines.

The top label says VENT. Most glow engines nowadays run best with muffler pressure. This line is very often connected to the pressure tap on your muffler. When you fuel the airplane using the line labeled Fuel Dot, you discover that the tank is full when fuel overflows out that VENT line, wherever it goes. If it can quickly and easily get out of the muffler, you have no problems seeing that the tank is full just as soon as it is full. If the muffler layout doesn't do that, many people put a T in the vent line and run the extra line to wherever the Fuel Dot line goes. They have two lines sticking out somewhere and both are plugged. The attached picture shows how I do most of my airplanes.

The two lines are pushed into the cowl in the picture. That's how they are except when fueling. Pull them both out and remove the plugs to fuel. Into the front one that goes where the Fuel Dot line in RCKens picture goes, and when full, you'll see overflow out the rear one.

works like a charm

The T's available at most LHSs are absolutely adequate and dependable with today's excellent silicon fuel tubing.

The plugs are sold in packs of two. They do what Fuel Dots do. There is really little difference in function or reliability. Both the plugs and dots are as reliable as your ability to stick a plug into a hose.
Thanks DA ROCK I appreciate the information. I have only used 2 line set ups before. I'm still not sure how your set up is working though. I have alway experience pulling the exhaust line off and seeing the fuel run out and I know the tank is full. How does putting a T adapter in the line keep the fuel from going into the muffler?

I posted a drawing of what I think you are saying. Sorry I didn't go to art school. lol I hope I am making sense and don't sound stupid about this. Thanks for the help.
Attached Thumbnails Click image for larger version

Name:	Pn36378.jpg
Views:	714
Size:	21.2 KB
ID:	965558  
Old 06-07-2008, 02:40 PM
  #7  
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,517
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

I actually didn't describe my plumbing setup because I use two different ones. I use uniflow most times, but will use what RCKen's picture shows for airplanes I'm not going to stunt much.

When you have all of your fuel lines enclosed and unreachable inside a cowl, you have to make at least one of them available to the outside world. You need the fill line available. A plugged line that comes through a cowl hole or a fuel dot on the cowl itself work for making that fill line available. But if your muffler isn't in the right place to show you overflow immediately, then you're going to need two lines available to the outside world. And that second line can be plugged or dotted too.

How does the T line work? Great. It's only use is to show the tank overflow. And that won't happen except when the tank fills and fuel starts to flow out the overflow. Yes, the overflow goes to the muffler and out the T line, but as soon as you see that fuel you stop fueling. It isn't a big deal. And if you want, you can arrange the T in the line so the overflowing fuel's momentum goes straight through the top of the T to the outside world instead of the muffler. Works great and the muffler pressure doesn't care if it's got to make a right angle turn.

With either uniflow or conventional when you have two lines showing to the outside world, you unplug them both to fuel. One will be the fill and must always be used for that. You unplug both lines and fill into the correct one. When the overflow appears out the overflow line, you stop pumping and plug both lines.
Old 06-07-2008, 02:43 PM
  #8  
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,517
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

BTW, have you noticed the different color silicon fuel hose in the LHS? I've found that having at least one color other than clear works really well.
Old 06-07-2008, 04:12 PM
  #9  
 
Join Date: Jul 2005
Location: Jacksonville, FL
Posts: 4,865
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

3 line system and use 2 clunks in the fuel tank so you can de fuel
Old 06-07-2008, 07:26 PM
  #10  
 
Join Date: Aug 2007
Location: Pittsfield, MA
Posts: 1,610
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

Two stupid questions:

1) Stated above in post 9 jetmech05 says to use two clunks. Is this correct? One on the pickup line to the carb and one on the fuel dot?
2) When you refuel, disconnecting the vent line to the muffler, and using the fuel dot won't the pressure of fueling push some of the fuel up into the carb through the pickup line? Or does the clunk prevent that?

I am going to use this setup with my now completed PT40. And if all goes well I will be converting all my planes to the 3-line.
Old 06-07-2008, 11:20 PM
  #11  
Senior Member
My Feedback: (3)
 
combatpigg's Avatar
 
Join Date: Nov 2003
Location: arlington, WA
Posts: 20,388
Received 27 Likes on 25 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

If you can access the pressure line at the muffler, use that line to fill the tank. Stand the plane on the spinner and if you think about it, close the intake window on the crank. Now simply gas it up until fuel spills out the carb. If you are a "neatness freak", just fill a pre-measured amount with a syringe.
Old 06-07-2008, 11:27 PM
  #12  
RCU Forum Manager/Admin
My Feedback: (9)
 
RCKen's Avatar
 
Join Date: Jul 2002
Location: Lawton, OK
Posts: 27,787
Likes: 0
Received 27 Likes on 24 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up


ORIGINAL: shd3920

I am going to use this setup with my now completed PT40. And if all goes well I will be converting all my planes to the 3-line.
My big question here would be "WHY?" I have plenty of planes that I use a 3 line setup on, but if the truth be known I will strive to use a 2-line setup whenever I can. I subscribe to the K.I.S.S (Keep It Simple - Stupid) theory in building planes. If I can make do with a 2 line setup there is no need to go through the added hassle of a 3-line setup.

But to answer your questions above. Yes, you can have two clunks in the tank. The first one is on the fuel pickup line that goes to the carburetor. The other clunk is on the fuel fill line. This will allow the fuel to be pumped out of the tank. You can forego the clunk on the fill line and put a simple piece of tubing bent down to the bottom of the tank at the front of the tank. To pump out the fuel simply lift the plane up on it's nose so the fuel flows to the front of the tank.

The only time that fuel will come out the carb when fueling with a fuel dot is if you have a T-fitting in the fuel line, with the "T" hooked up to the carb, tank, fuel dot. But you can simply close the carb before pumping in the fuel. In a 3 line setup this usually isn't a problem because overflow will go out the muffler pressure/vent line first.

Ken
Old 06-07-2008, 11:53 PM
  #13  
 
Join Date: Aug 2007
Location: Pittsfield, MA
Posts: 1,610
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up


My big question here would be "WHY?" I have plenty of planes that I use a 3 line setup on, but if the truth be known I will strive to use a 2-line setup whenever I can.

Simply because I wanted to do something different from my other builds, I did this mod as well as other simple mods (taildragger, rear-mounted servos, dual aileron servos) and I like its looks. Also it is a tight fit at the carb for my hand to reach in so I have to use pliers to hook the line on, and I am thinking that continued hookups this way will puncture the line.


Old 06-08-2008, 01:33 AM
  #14  
My Feedback: (1)
 
JohnBuckner's Avatar
 
Join Date: Dec 2001
Location: Kingman, AZ
Posts: 10,441
Likes: 0
Received 10 Likes on 10 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

All two line systems. Never agine have to use pliers to fuel a rear needle valve engine. Never agine go looking for a lost dot in the grass. Enjoy the added reliability and fewer failure modes of a two line system. No need to sacrifice fuel capacity to second clunks and lines. very easy fueling with or without cowls. Finally enjoy the ability to use the pinch tuning method when using two strokes. All are two line systems:
Attached Thumbnails Click image for larger version

Name:	Qo40696.jpg
Views:	642
Size:	230.9 KB
ID:	966109   Click image for larger version

Name:	Id95704.jpg
Views:	376
Size:	232.4 KB
ID:	966110   Click image for larger version

Name:	Lr39479.jpg
Views:	382
Size:	249.1 KB
ID:	966111   Click image for larger version

Name:	Vo37180.jpg
Views:	333
Size:	227.7 KB
ID:	966112   Click image for larger version

Name:	Qb36915.jpg
Views:	321
Size:	266.3 KB
ID:	966113   Click image for larger version

Name:	Of58699.jpg
Views:	358
Size:	250.5 KB
ID:	966114   Click image for larger version

Name:	Oq20607.jpg
Views:	299
Size:	233.6 KB
ID:	966115   Click image for larger version

Name:	Ji28588.jpg
Views:	303
Size:	212.7 KB
ID:	966116  

Click image for larger version

Name:	Cb54055.jpg
Views:	277
Size:	238.9 KB
ID:	966117   Click image for larger version

Name:	Mz16775.jpg
Views:	448
Size:	230.2 KB
ID:	966118  
Old 06-08-2008, 03:06 AM
  #15  
 
panzerd18's Avatar
 
Join Date: Oct 2005
Posts: 268
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

You could use one of these.

http://www3.towerhobbies.com/cgi-bin...?&I=LXK135&P=0

This allows you to have only two fuel lines. Mount it on the cowl or inside the cowl to fuel.

I am doing this with my new cowled model but I'm not sure how I will know when the tank is full when I cannot get to the exhaust line? Someone said when you use an electric fuel pump you can hear the pump change pitch as it reaches full?
Old 06-08-2008, 08:00 AM
  #16  
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,517
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

You can actually have NO plugs or trick fueling devices at all in a 2 line system on a cowled airplane.

Beginners, there are a LOT of plumbing strategies. This discussion actually is confusing a couple of different ideas that have nothing to do with each other.

Why use a 3-line system? Because Uniflow needs 3 lines and Uniflow is worth having to solve problems that happen with some airplanes. Or because you've got a cowled setup and want a carb pickup line with no interruptions. And you don't want to buy a device that overcomplicates a system that doesn't need it. Or a number of reasons.

I've got a couple of models that have benefitted from having Uniflow. I fly the hell out of them and the engines run significantly better with Uniflow. How do I know the engines run better with Uniflow? They started out without it. Do you need it? Probably not. Not yet. But if you ever do, it's there to try. It might help, it might not.
Old 06-08-2008, 08:13 AM
  #17  
Senior Member
 
Join Date: Aug 2007
Location: Rockwall, TX
Posts: 200
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

Do you guy's put a fuel filter on the carb fuel line? i.e. Tank-fuel line-fuel filter-fuel line-carb. Fairly new to the glow world so all my engines have been new, but a couple getting older, someone suggested this at the field the other day. Thanx.
Old 06-08-2008, 10:56 AM
  #18  
Senior Member
My Feedback: (3)
 
combatpigg's Avatar
 
Join Date: Nov 2003
Location: arlington, WA
Posts: 20,388
Received 27 Likes on 25 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

If you have a high quality filter in your gallon jug and keep the rest of your fueling operation clean [not hard to do], there is no need for an onboard filter. I fly mostly .049-.074 powered stuff and they need the fuel to be immaculate.
Old 06-09-2008, 08:37 AM
  #19  
Senior Member
My Feedback: (4)
 
MinnFlyer's Avatar
 
Join Date: Apr 2002
Location: Willmar, MN
Posts: 28,519
Likes: 0
Received 8 Likes on 8 Posts
Default RE: 2 or 3 Line Fuel Tank Set Up

That picture is an older one I did.

This is the new and improved version.
Attached Thumbnails Click image for larger version

Name:	Wu59795.jpg
Views:	868
Size:	60.8 KB
ID:	967123  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On


Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.