I am building an Ultra Sport + that has a cowl and since this is my first cowled airplane I was wondering what the best fuel line setup is? I am powering it with an OS 70 Surpass 4 stroke inverted if that makes any difference. Do I use 2 line? 3 line? Refueling Valve? Fuel Dots? I have heard of people who have had trouble with engine flooding upon refueling. Thanks

I highly recommend one of 2 methods for minimal problems.

1. Use a 3rd line system. What this involves is havining 2 clunks in the tank. One line with a clunk goes to the carb, the other line with the clunk goes to a fuel dot or other means of plugging the line, yet still be able to access it. DuBro "Fuel It" is an excellent setup and is complete. The "fuel dots" are just the plug for the fuel fill line and the retainer to hold the plug. You have to supply the additional tube for the tank, fuel line and clunk for the tank. The typical installation for the fuel dot retainer is to drill a (usually) 1/2" hole in which the retainer is fastened. The plug part is either a press fit or screws in with your fingernail.

2. Use a 2 line system, but have the line going to the carb come outside the plane/cowl. This line then has a short piece of copper/brass tube slid in one end. The other end has the fuel line that goes to the carb. To refuel, you disconnect the carb end of the fuel line from the copper/brass tube and put your fuel fill line onto the tube and fill/remove your fuel. There is a commercial system out there for this, but I don't know the supplier/manufacturer.

I use the DuBro Fuel It system on my planes. I have not had any problems with it and I like the idea that I can locate (conceal) the fuel fill/removal where I want. With the DuBro Fuel It or a fuel dot, make sure the throttle is closed when refueling (prevents flooding the engine) and watch the muffler. When fuel comes out of the muffler, the tank is full. With the 2 line system just watch the muffler.

Hope this answers your question.

Actually, Dubro calls it " the fill it" system: http://www2.towerhobbies.com/cgi-bin...?&I=LXAHE1&P=7

But who's counting. I like these: http://www2.towerhobbies.com/cgi-bin...4&I=LXES36&P=K if there is a solid structure to mount it on such as a fuselage wall. This allows you to keep a 2 line system very easily with NO chance of flooding the carb. I don't think it would work on most flexible cowlings very well.

If i am not mistaken the Robart fuel set up is huge (for 1/4 scale planes) or something like that

I've got two planes with the Dubro quick filler and a 2 line setup. It has worked fine. My subsequent planes have a 3 line setup. The engines are mounted inverted. I've had no problem with flooding. While fueling, I have the carb set at idle position. Even if I do get some fuel in the carb during filling, it's not going to flood the engine, unless liquids can flow uphill. However, these are all 2 strokes.

SwampFlier-RCU------- Sorry, I've got the Robart fueler mounted on 2 of my 40 size planes right now and will be putting one on the Kaos (60 size) I am putting together too. Works well when you can't get at the carb to pull off the fuel line for fueling and don't want to use a DOT either. IMHO Some of the new remote needles can make fueling more of a challenge than the old needles did. I do not personally care for 3-line systems, if you (or others) do that is fine.

Fuel Dot w/ 3 line setup in tank. Allows for complete defueling, and as a plus if you have fuel problems at the field, you can always switch your supply line to the other pickup. Not to mention that if I have to carry a special adapter to fuel my airplane, chances are it will not make it to the field with me.

Andy

Hi fstevenj,

You will get a huge divergence of opinion on this topic and all will be correct to their own lights, it's you "who pays your money and takes ya pick".

I have used Dubro fuel valves for many years without a problem. Many will tell you horror stories of unreliability, loss of valve connector etc, etc but I like them.

To mount the valve I use a small piece of angle alloy behind the cowl so the valve mounts to the engine box and the hole in the cowl is just large enough to allow the fitting to reach the valve.

Cheers,

Colin

Thank you for all the advise. After looking at my fuel tank (great planes) it seems that it is not setup to handle two clunks so I guess that option is out. The dubro valve looks ok. Is it alright to mount it in the fuselage. The way the aircraft is set up there is a large gap between the firewall and the front of the gas tank. The robart refueler looks interesting also, does anyone else have any experience with this unit? Thanks again.

I've used these also: http://www2.towerhobbies.com/cgi-bin...&I=LXK135&P=ML

They only work with relatively thin structures, direct onto cowlings or on a bracket right below the cowling. Easy to connect hoses to wrong fitting during install but also easy to figure out. There is a gas version too, be sure you get the right one.

Lots of choices.

Here's the fuel system I set up for my Ugly Stick 40. I think it turned out pretty well.

The tank is set up to use 2 clunks. The third hole in the stopper is plugged. You unplug it when you insert the piece of tube through the stopper.

The piece of metal tubing and the clunk are not supplied with the tank, you have to supply it.

The DuBro Fill It system has the tubing, clunk, etc for a complete 3rd line setup if that is the way you want to go.

Just wondering - what kind of mount does troyswan have there for the fueler valve?

I'm going to be setting up my first cowled engine. Plan on going with a valve type setup and remote glow and wondering how you actually mount them. Do you mount them onto the cowl or inside and just allow the hole to be the access point?

Looks like some kid of bracket he found somewhere. You could just bend one up out of some stock or you could send him a PM and see if it is anything in particular. Most likely it wouldn't work with your cowl. If your cowl is stiff enough you can mount directly to it, otherwise bend up a bracket of some sort to hold it just below surface of the cowl. If a bracket, it will need good support so it doesn't give too much when you plug in and have it bend and eventually break.

I'll be putting this on a H9 Miss America P-51 and the cowl is fairly thing. I was just concerned about it. The fueler not so much but the remote glow.

I would think that the same rule would apply, especially since ignitor will be attached during a vibration period. I think a separate bracket would be best in this case. Keep it short and attach to the firewall, if there is room, and it will look good.