Fuel dot setup
 

Im in the process of building a H9 P-47 thunderbolt 60 with a saito FA100 in it. The engine mounts slightly inverted. About 7 o'clock to 8 o'clock to be exact. My question is this. By puting a fuel dot in it due to the cowl, would a "T" work or would it be advised to pick up a tank with 3 lines. I have seen people use the T's before, but not inverted. I wonder if it would be prone to flooding by using a T rather than a 3 line tank. I dont want to have to remove the cowl to get to the glow plug to pull it if it floods. I plan on using a remote glow system to avoid cutting up the cowl.
Any input would be appreciated.

RE: Fuel dot setup
 

A 3 line tank is the answer, (not Uniflow)
You will find that a 3 line tank is easier to use and maybe will become a stock set up in your next build.
There several variants when using a 3 line set up but go simple and use only one line directed to the carb, a second line to the muffler pressure and a third line just for refueling, do not forget to plug this line after refueling.

RE: Fuel dot setup
 

Do the three lines, it works much better. I have tried using a tee and it ends up flooding the carb when filling unless you pinch off the line going to it.

RE: Fuel dot setup
 

I figured it would flood it. Thanks for your input guys. Its appreciated.

RE: Fuel dot setup
 

I think alot of this answer depends on what motor your gonna be using. I have a H9 P-51 with a pumped O.S. 1.20 4 stroke that mounted totally inverted. My engine has a vent nipple on the back of the crankcase that I have running back into the tank,so I'm using 3 lines. I also use a "T" that connect to my tank/vent nipple/and overflow filling line(this engine doesnt have a pressure line in the muffler). I have one line going into the tank for the actually fill line. And of course the other is the carb line coming out of the tank.

But most likely your gonna NEED a 3rd line in your tank. "T's" arent bad if you put them in the right spot,but if you were planning on putting the "T" between your tank and carb.......that would likely not be good.

RE: Fuel dot setup
 

There will have to be a line that fills and a line that overflows. If you run the lines as alfredbmor described, the overflow goes into the muffler. Depending on the muffler and where it is, that overflow can be hard to spot. If you go with that layout and want it to work well, there needs to be a fairly straight downhill run from where the pressure tap is in the muffler to the muffler exhaust pipe. A buddy has one airplane where the muffler takes maybe an ounce of fuel before it starts to pour out the exhaust.

My P47 tank has 3 lines. I've got a T in one of the three lines. Two of the lines are shown in the picture. I have had those lines rigged with Uniflow and without. Whenever you have all the hoses enclosed in a cowl, you're going to have to have a T or something like a fuel dot. Fuel dots have never been dependable for me.


I've used the OS91FX's OEM muffler in the P47. It does not leak overflow fuel quickly. So I've got a T in that line.

I use a hemostat to clamp that line between the muffler and the T. It works well. I don't mind dealing with the hemostat. It's cheaper than a fuel dot and 100% dependable.

I pull both lines you see in the picture out and pull their plugs to fuel. Fill into one line, look for instant overflow from the other that says the tank is full. With slightly different routing to not have uniflow, those two hoses do exactly the same. And the hemostat is still needed. I think the long one I have cost $5.

When you've got all the lines behind a cowl, you have to be lucky for them to work without needing to pinch one of the lines. And you will need a T or a special Fuel Dot.

RE: Fuel dot setup
 

darock, what issues is it you have had with fuel dots? Is the vibration on the light fiberglass cowl too much for them? I will be mounting my saito in the recommended location with the muffler coming out the bottom on center. I see what you are saying and a hemostat and T on the pressure line just might be the route I go. ?

RE: Fuel dot setup
 

You wouldnt want to use a hemostat such like Darock. Sounds like he only does it to divert the overflow from going to his muffler because of his particular muffler as it would have to fill with fuel before overflowing. But,if your using a saito with its stock muffler....you wont have any problems with your fuel filling up the muffler. On a saito used the way you are,it will overflow no problem.

I use a fuel dot on my edge with its saito125 and love it. You'll still need to install a 3rd line into your tank though. The only way you can pull off your setup with only 2 lines is to T between the tank and carb,thus flooding your carb. Now you could just make sure your carb is closed ALL the way and pray it doesnt leak while fueling and make a terrible mess inside your cowl(which you likely will). Or,you could use the hemostat to pinch off the line to the carb while fueling,but this is HIGHLY not recommended becuase its never good to tap into the carb line to begin with,plus the hemostat could easily puncture wholes in your carb line,thus making your engine suck air and kill them motor.

Put in that 3rd line(its the only sensible thing to do),put on that fancy fuel dot and let the overflow come out your muffler,and you'll have a GREAT running setup! :D

RE: Fuel dot setup
 

I've only tried a fuel dot once. It wound up sticking on fueling and losing pressure in flight, all in the same weekend. And while trying to fix it discovered that a couple of my flying buddies didn't use them anymore. They'd had the same problems.

The hemostat actually isn't needed in every case. Depends on what line you're placing the T in. And how you fuel. My hand pumps put out pretty strong pressure and have no problem delivering full flow into the tank at the same time it merrily pumps about as much fuel down the other line off the T. I've got one plane with the T in the carb line. Even with my pumps pressure, fueling using that line doesn't flood the engine. Most needle valves restrict flow lots more than an empty tank resists filling (which isn't much).

RE: Fuel dot setup
 

Nope. The hemostat keeps the fuel that's going into the tank going into the tank. The fuel going into the tank sees two paths. One into the tank and one into the open muffler. It goes both ways equally, unless the hemostat closes the line into the muffler. Uniflow systems usually are filled from the hoses that go into the bottom of the tank. Those would be the pressure line and the pickup line. I happen to T the pressure line for fueling.

RE: Fuel dot setup
 

Umm....I'm not so sure were all on the same page as far as "fuel dots" go. A fuel dot to me is simply a fancy looking little fitting that your fueling line sticks out of through your cowl/fuselage with a stopper in. I think some of you might be thinking of a "kwik-fill" fuel valve. It also is a fitting for your cowl/fuselage,but is actually a valve used for fueling. I've never used a kwikfill valve,but thinking about it now.......this would work for what f_shawn is trying to do without the need for 3 tank lines. It would go inbetween the carb and tank and shut the fuel off to the carb while fueling. I will say that I have heard alot of negative things about them leaking and again,I personally would not recommend one because again,I like a straight connection from my tank to the carb with as little a chance as possible for an air leak or any other leak.

Here a pic of a fuel dot(2 of them in this pic).....and a kwik fill valve.

http://centralhobbies.com/Fuel/fuel_...s/tetdots.html

http://www3.towerhobbies.com/cgi-bin...?&I=LXD745&P=0

RE: Fuel dot setup
 

You're right.

Never seen that Tettra dot. Everybody at the field calls the Dubro fill valve a fuel dot.

When I was told about them a couple of years ago, I swung by the LHS on the way home from the flying field and asked for a fuel dot. The hobby shop owner walked over to the wall and pulled down the Dubro valve without saying a word.

I'd say the consensus at the field is that they're not dependable.

If you look closely at the picture of my P47, you can see what I call plugs. Tower sells 'em and you know what Tower call's 'em? http://www3.towerhobbies.com/cgi-bin...&I=LXK138&P=ML

So it looks like nobody is on the same page.

RE: Fuel dot setup
 

If I am not mistaken, the plugs in the Tower link that da Rock posted are only plugs - there's no cowl receptacle to plug them into.

Also, I think those Tettra dots are for smaller fuel lines.

RE: Fuel dot setup
 

I know the difference between a fuel valve and a fuel dot. I have seen several guys using dots, but they were running gassers. Thats why I asked if they would work due to the air pressure used to pump the fuel from the tank to the carb. I understand what darock is saying about them leaking. I guess I thought they would seal better. I have also read mixed reviews on the fuel valves working right for some people. If its on the fuel line that it leaks, I suppose a couple spring type hose clamps could be applied? I just want to get it right the first time and do as little cutting on the cowl as I can. I really do appreciate your input. Its great to be able to rely on the experience you guys have.

RE: Fuel dot setup
 

The problem I have with fuel valves has nothing to do with leaks.

I am NOT a very organized person. I am notorious for walking into a room with a screwdriver in my hand, setting it down to pick up a pair of pliers, walking out without the screwdriver, and then wondering what the hell I did with the screwdriver (Sound familiar?)

So here's what happens to me:

I put a fuel valve on one of my planes, but when I have to fuel up another plane, I remove the one-of-a-kind fueling probe and promptly lose it.

Now it's easy to say, "Just put a Fuel Valve on ALL of your planes"

Yea, right. Do you know how many planes I have? I don't even bother to count anymore. And even if I did have one on every plane, I often share fuel with my dad, brother, or even another club member, so the chances of never removing the one-of-a-kind fueling probe is slim - and the chance of losing it is far too great.

I'm a devoted Fuel Dot user!

RE: Fuel dot setup
 

What brand of dots do you use minn? Im alot like you and have a bad habit of misplacing items as well. If you dont see an issue with them leaking, I will go that route. You have helped me before and gave me great advise on a wing repair. This will be my most expensive bird and I just dont want anything wrong with the setup. It will be my 2nd arf. My first arf passed with flying colors, so I want this one to do the same when its ready to fly.

RE: Fuel dot setup
 

I've never had a problem with a fuel DOT leaking.

As far as brands, I often use the DuBro:

http://www3.towerhobbies.com/cgi-bin...&I=LXAHE1&P=SM

The DuBro type have a receptacle that glues to the cowl.

Or these:

http://www.horizonhobby.com/Products...?ProdID=HAN115

On these, the receptacle screws onto the cowl

RE: Fuel dot setup
 

I've also used both of these and they work great. I really like the DuBro set since it gives you the tube and clunk for the 3rd line.

RE: Fuel dot setup
 

I am not married with any of them but I do prefer the Hangar 9 Fuel dot or plug or what ever you name it. I also have other planes with the Quick filler valve and I have had not problems untill now, I believe that the oldest I have should be around 5 years old. I do prefer the fuel plugs because of their price and when the engine is completly inside the cowl I use a couple of them with a T, then I am able to catch the overflow fuel inside an extra tank that I use to carry in my tool box.

RE: Fuel dot setup
 

OMG MinnFlyer, that same thing happened to me, except I had put the screwdriver in my back pocket. Thought I was the only person who did this.[sm=what_smile.gif]