Notices
Scale Racing Discuss all aspects of semi-scale pylon racing.

Fuel Line Connectors

Old 01-10-2022, 07:11 AM
  #1  
SoCalErv
Member
Thread Starter
 
Join Date: Aug 2020
Posts: 35
Received 0 Likes on 0 Posts
Default Fuel Line Connectors

Last Saturday at the Chino Tune event I noticed most Gold and Silver birds had quick couplers on the vent and fuel lines.

Building a World Models Spitfire and would like to know what are these connectors, how they work and where I can purchase them.

Thank you for any help you can provide.
Old 01-13-2022, 01:05 AM
  #2  
Iron Dog
 
Iron Dog's Avatar
 
Join Date: Feb 2009
Location: Sacramento, CA
Posts: 1,343
Likes: 0
Received 1 Like on 1 Post
Default

Erv,

I was not at that race, so unable to know exactly what you saw; but I have been racing warbirds since 2004, believe I understand what you are referring to. I have used a few different brands -- most with success. Reliability is key to success in this sport, so hopefully you avoid some of my initial issues in this area.

I started with Tees and fuel dots from Fourmost Products. These were plastic, and I once had a fuel T split on me during a race. I believe I caused the issue, because my fuel lines were too short, and when I pulled the fuel line far enough out of the fuselage to connect it to my fuel pump, I stressed/cracked the plastic. Using a pressurized YS engine meant fuel went everywhere inside the front portion of the fuselage. I never trusted the durability of Fourmost Tees since, so do not feel comfortable recommending them for your racer.

I decided that aluminum Tees and fueler mounts/dots were worth the extra price. I had some fellow racing friends that machined them, and they worked great; but, they have since stopped making them.

Next, I went to PSP manufacturing. These were generally good, too. But, twice, I found the retaining nut on the fueler mount to be machined incorrectly, making it extremely difficult to securely install the fueler mounts. I tried going to their web address to get a direct link to the parts for you, but I do not believe they are in business anymore. Their web page does not come up, and my local hobby shop has not had their products for a couple years now.

What I have been purchasing lately, are the Tees and fueler mounts from MPI (Maxx Products Int'l.). It is very late in the evening, so their web page is currently under "maintenance downtime"; so again, I am unable to provide a direct link for you to follow to order them from the manufacturer. What I can tell you, is that their web address is "maxxprod.com" and they sell the Tees in pairs, the fueler mounts in pairs, or one mount and one T packaged together. I most regularly purchase 2 packages of the latter, "Stock No. ACC229", pictured below. The last time I purchased these from my local hobby shop, they were $3.99 per package. I like that these Tees are double-barbed to hold the fuel line securely.


Contents of MPI #ACC229, clockwise from bottom-left: fuel T, fueler mount and retaining nut, fuel dot (line plug), nylon washers/spacers.


I drew a quick sketch of where I install the Tees in my racers, to help you visualize the critical element of this set-up. (Please see, below.)

One T is placed in-between the fuel tank and the one-way check valve (on what the YS diagram labels as "Tube A"). Another piece of tubing (usually several inches long) is connected to the T, which runs through one of the fueler mounts and is plugged by the fuel dot. This line is the pressurized vent line, which will also be connected to a catch-tank during refueling. I am assuming you will be using a YS engine; so after you run your engine, the fuel tank will be pressurized. The fuel dot on the pressurized vent line must be disconnected first, to relieve this pressure in the tank, and avoid the fuel in the tank being very forcefully sprayed out of the fuel line, when its dot is removed.



The other T is placed in the fuel line, between the fuel filter and the tank (on what the YS diagram labels as "Tube B"). Another piece of tubing (usually several inches long) is connected to this T, which runs through the second fueler mount and is plugged by another fuel dot. This dot is removed only after the vent line's dot is unplugged, and the tank has been de-pressurized.

The fueler mounts are installed in the side of the fuselage, somewhere in-between the firewall and the fuel tank; or, into the cowl -- depending on model design and modeler/pilot preference.



You can see the installation of the fueler mounts/dots in my P-39s, above. They are located just below the nose-art graphics on both airplanes. The vent line is MPI's silver AC229, and the fuel line is the green anodized version from PSP.



On my Red Baron above, I used silver fittings for both, because that is all I had on-hand, at the time. They are visible behind the engine. I installed the fueler mounts before painting, so only the fuel dot is silver. I should have painted one of the dots, while I was at it, so one would be more readily distinguishable from the other. But I staggered the height on these to more easily differentiate. The top is the vent line, and the lower is the fuel line -- same configuration as the lines as they come out of the Hayes tank.


A few recommendations:
1. Use 2 different colors of fuel tubing; and, it helps to be consistent with these colors with all your racers. I always use the standard blue tubing for the pieces that make up my vent line. I use either the Brodak amber-colored tubing, or Sullivan clear tubing, for my fuel line components.
2. Only use a quality fuel tank with a YS engine. Many brands do not handle the pressure without eventually bursting; or may expand dramatically, and in a tight fit can crack your fuselage or bind/damage other components. Most of my colleagues and I look for rigid, seamless tanks, only using Hayes or Tettra tanks.
3. The MPI fueler mounts, Tees, and dots only come in "silver." I use older color-anodized PSP mounts/dots for my fuel line, and plain silver (effectively no color) for my vent line. My reasoning is that fuel has color, and air does not. This helps me know at a glance, which line is which; without having to first pull the lines out to identify which is the vent line, and which is the fuel line. If you only have access to the MPI fueler mounts/dots, you might consider marking or coloring the dot in some fashion.
4. I recommend using Loctite (or similar thread-lock) on the threads of the fueler mount and retaining nut. I have had the retaining nut loosen and fall out, over time, due to vibration, when I failed to do this. (Not fun to have to disconnect and pull everything out, then re-install, just to be able to access and tighten a nut!)
5. The MPI dots are threaded, and screw into the mounts. To avoid excessive twisting (& possible kinking) of any lines, I rotate the dot (& line) counterclockwise to counter much of the clockwise twisting of the lines when I screw them in, after fueling is complete.
6. When unplugging the dot from the fuel and vent lines, pinch the tubing just in front of the dots with your fingers, first. Unplug the dot and point the opening of the line away from you, other pilots, your transmitter, and any other equipment -- before you release the pressure. Even the vent line will expel a slight amount of fuel during this process. The fuel line will expel even more, so I often choose to connect it to my fueling probe to avoid wasting the fuel and making a mess during de-pressurization.

Last edited by Iron Dog; 01-13-2022 at 02:47 PM.
Old 01-13-2022, 01:12 AM
  #3  
Iron Dog
 
Iron Dog's Avatar
 
Join Date: Feb 2009
Location: Sacramento, CA
Posts: 1,343
Likes: 0
Received 1 Like on 1 Post
Default

Hope that helped, Erv. Good luck with your set-up; and if you have any follow-up questions, I will do my best to answer them.

Ollie
Old 01-13-2022, 01:55 PM
  #4  
Iron Dog
 
Iron Dog's Avatar
 
Join Date: Feb 2009
Location: Sacramento, CA
Posts: 1,343
Likes: 0
Received 1 Like on 1 Post
Default

I felt bad about not being able to give you any specific, direct product links; so I did a little research this afternoon. While I have not personally used the following specific products, I did find some similar accessories on both the Central Hobbies and Chief Aircraft websites, that might work for you:

https://www.centralhobbies.com/cat3....t=21&subcat=38 (There are 4 pages of accessories. Just ensure that they are designed to fit medium fuel tubing, because some of the descriptions do not state specifics.)




https://www.chiefaircraft.com/han-116.html


Perhaps some other racers will chime-in to offer their experience &/or endorsement of one product, over the other?

Last edited by Iron Dog; 01-13-2022 at 02:05 PM.
Old 01-14-2022, 09:07 PM
  #5  
SoCalErv
Member
Thread Starter
 
Join Date: Aug 2020
Posts: 35
Received 0 Likes on 0 Posts
Default

Great information. I will be running a Saito 100 so the lines will be somewhat different.

In your diagram, when you fuel do you pinch the hose to the carb?

Thanks for the guidance.
Old 01-15-2022, 11:51 AM
  #6  
Iron Dog
 
Iron Dog's Avatar
 
Join Date: Feb 2009
Location: Sacramento, CA
Posts: 1,343
Likes: 0
Received 1 Like on 1 Post
Default

Sometimes I have to pinch the fuel line . . . Other times, I do not.

I will attempt to explain:

With most of my YS engines, if everything is working ideally, when I cut my throttle to land in the previous flight, the throttle is completely closed, the regulator is working optimally, and fuel does not force its way through, and out of the carb, prior to me relieving the pressure in the vent line. Under these conditions, I can generally refill my tank without excess fuel working its way out through the carb; therefore, not needing to go through the hassle of pinching the fuel line with hemostats.

I have had times that I have had to pinch the fuel line during refueling; and, especially on hotter days (when everything wants to expand -- building extra pressure), even to the point of having to leave the hemostats on, right up to the point I am ready to start my engine. It took me awhile to figure out the pattern, but what I have found (in my experience) is that the times that fuel "leaks" excessively seems to be in the instances when:
1. My diaphragm was warped, needing replacement;
2. I had dirt or other foreign material in my regulator, keeping it from closing-off as it is designed to.
3. I have been unable to get my engine running reliably with the regulator at the "factory default" setting. I had to open the regulator more than usual, and then constrict my high speed needle setting to compensate for excess fuel flow -- not ideal;
(Note: this last circumstance pertains to the older YS models that have an adjustable regulator; such as the .53, .63, .91, 1.10 and 1.10S models. The newer .70, .80, 1.15 and 1.15WS models use a new regulator design that is not adjustable.)

There are many racers who choose to always pinch the fuel line when filling, and many even leave hemostats on, up to the start of the engine. They want to minimize any possible risk of engine starting issues, due to potential flooding.

As I stated in a prior post, reliability and consistency are keys to success in this sport, so ultimately it comes down to your particular engine and fuel system set-up and personal preferences -- tempered by your experiences (of what has "bitten you in the butt," in the past).

I have been discussing this topic from the standpoint of using YS engines in your racer, because I did not know, until now, what your engine choice was, so I had to make an assumption. Also, others are reading these posts, many/most will likely ultimately choose a YS engine; so hope my advice gets them started successfully, too.

Now that I know you are using a Saito, I can tell you that some of this advice will not pertain to your particular set-up. I do have two Saito 100s (for a Condor Model Products P-38) as well as a .72 (for a sport plane), but have not used them, yet. Therefore, I do not have specific enough experience with your engine to offer valuable advice.

"Top Gun" Tom is one of my friends and fellow racers. He is one of the few at Sacramento Area Modelers (SAM) that uses Saito engines for his Bronze racers, and even in one Silver class racer, I hope to see him out at the SAM field tomorrow. My buddy Steve will definitely be out there tomorrow; but he only used Saito 72 or 82s, and only did so briefly. Whoever is there that I can talk to about his experiences, I will; and, hope to be able to pass-on more specific advice he/they might have for you.

Ollie
Old 01-18-2022, 05:34 PM
  #7  
Iron Dog
 
Iron Dog's Avatar
 
Join Date: Feb 2009
Location: Sacramento, CA
Posts: 1,343
Likes: 0
Received 1 Like on 1 Post
Default

Sunday, I spoke to a couple guys that have raced with Saito engines out at the SAM field:

Tom has run Saito .72 and .82s in Bronze, and used a 1.25 in Silver. He invert-mounted each of them. He stated that all 3 leaked out of the carb, so he had to leave on hemostats until he was ready to start the engine. He used 30% nitro fuel, and did not use fuel Tees in his setup. He stated that he "had to be right on the pylons to be competitive" [on break-out time].

Steve used a Saito .82 with 20% nitro in Bronze. He was busy running our Outlaws race, so I wasn't able to get more from him than that.

But, I was able to get quite a bit of information from David, who was running the same engine you are. David invert-mounts his Saito 100 in his World Models P-51. He uses 30% fuel and an APC 12 x 12N prop, and was competitive with this configuration in Silver, last year. He said that he would usually run just over the 2-minute break-out time -- usually about 2:05. Just when he thought he didn't have to ever worry about breaking-out, he did. He never experienced ANY leaking, and did not need to use hemostats at any point -- not even during fueling. He stated that he "didn't do anything special. It ran perfectly. I was even able to move the tank back to the CG without any fuel draw issues." He loves that engine. "It is reliable, easy to tune, and get parts."


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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.