SSGSPEEDMAN

The plane I have is the new model Evo from Bruce. I'm using the tettra bubbless 6.5oz tank.

I'm having a problem with fueling. I have everything CORRECTLY setup the way it suppose to be. When I start to fill the tank up, fuel just wants to start coming out {not solid fuel, but bubbles/some fuel}. I fill the tank when the the plane is right side up the way it suppose to be. Dad was testing with it last night and he saying that there may be some kind of rinkle on the bladder. With this problem I'm haveing, I'm only getting about 3oz of fuel in the tank before fuel starts coming out. Dad was able to eventually get the tank to fill up. But took too much time than it should normally take. Whats wrong with this setup?

Thanks,
Kevin

Jim Duda

Are you sucking ALL the air out of the bladder before you fuel it? What kind of syringe are you using to fill it? There is only ONE fuel nipple coming out of the stopper...correct?

I don't understand where fuel is coming out of...there should be NO OVERFLOW line on these tanks.

bl10

I use only two fuel lines. The engine feed line and the muffler pressure line. I use a JETT Tanker (syringe) to fuel my planes. If you are using third vent line per inst on box block it off and try this.
1. Using feed line suck all air out of tank.
2. Put clip on feed line to prevent air entering tank.
3. Remove syringe and fill with fuel. (8oz or so).
4. Attach syringe to feed line.
5. Remove clip.
6. Pull a little vacuum with syringe then fill tank.
7. When tank is full, easy to tell by amount of fuel going in, suck a little out to relieve tank pressure.
8. Put clip on feed line to prevent fuel running out.
9. Remove syringe.
10. Attach feed line to engine.

If using this procedure you can’t get tank full remove tank from plane and fill it watching what is going on. I’ve never had one I couldn’t fill.

Take Care
Barry

Ed Smith

Exactly what Jim says. Fuel cannot come out while the tank is being filled. Only one line goes into the bladder.

This is the way to set up the tank.

The piece of aluminum tube for the feed line should protrude about an inch into the bladder. On the end of this slip a piece of fuel tubing long enough to reach to the centre of the tank, no longer. In the end of the fuel tubing cut a VEE. About a 1/4" up from the end of the vee pierce a small cross hole through both sides of the fuel tubing using a piece of sharpened brass tubing. The vee and the cross hole prevent the bladder from blocking off the inlet as it collapses.

There should be only two lines to the tank. The feed line and the pressure line.

Fill as per Barrys' instructions.

Ed S

SSGSPEEDMAN

"{the fuel tank is made this way}"I have four fuel lines going to the tank. Three of them are for the bladder itself. 1 for carb, 2nd for vent on top of the tank, 3rd for vents for the fuel line. The 4th one is on the out side for pressureizing the tank.

I don't have a syringe. I just use a hand crank fuel pump. I haven't tried sucking all the air out, but I shouldn't have to when the 3rd fuel line is already venting all the air out of the tank when fueling the tank.

Kevin

Jim Duda

Kevin - you are defeating the purpose of the BUBBLELESS tank if you have any more than ONE line going into the bladder. You must use a syringe (most of us use the Jett Tanker) to evacuate all the air from the bladder before filling. YOU MUST COMPLETELY COLLAPSE THE BLADDER BEFORE FILLING IT! That's the part that makes it a BUBBLELESS tank.

Connect the bladder nipple to your carb and the pressure fitting on the side of the Tettra to your pressure (usually the muffler).

Then follow Barry's instruction to the letter!

js3

My Feedback: (3)

If there is a vent, you're defeating the purpose of the bladder. No, there should be only two lines; one goes from inside the bladder to the carb nipple, the second goes into the tank outside of the bladder. This second line connects to the muffler and provides pressure.

I've heard that you can fill a bladder tank with a standard fuel pump if you use a hopper tank (connected to the pump, not inside the plane) to provide pressure. However, I've never tried this as I've always used a syringe.

SSGSPEEDMAN

Well all I can say is thats the way it was made.

Kevin

BUDMAN27

You should make your own. I do and most of the time they work .

Ed Smith

The tank is made that way so it can also be used as a regular clunk tank without the bladder.

Oh, and by the way. How about a THANKS to all those people who offered help!!!

Ed S

bl10

Kevin:
Over the years pylon racers have figured out the best and simplest way to use bubbleless tanks. Yes the Tettra instructions diagram the multi lines you describe but as far as I am concerned you need a syringe to fill them properly. If you don’t want to spend the money on a JETT Tanker you can go to a large animal supply store and buy a clear syringe that holds about 5 oz. It is much cheaper but doesn’t last as long and makes fueling more complicated because you can’t fill the tank with one syringe of fuel. Just block the two vent lines with screws or something. When fueling with the smaller syringe be careful not to introduce air in the tank due to the tank not being full when coming to the end of the 1st syringe of fuel. In other words leave about 1/4 oz of fuel in the syringe don’t just push it to the end.

Take Care
Barry

SSGSPEEDMAN

the other thing I should say that the other two fuel lines are for convience. Because it is hard to reach the intake fuel line to fill the tank up with fuel. what the two fuel lines are for fueling and venting with out the inconvience of the having hard places to reach.


Now about the fuel tank that is made that way to use as a klunk tank or bubbless tank. Thats the dumbiest idea I've ever heard {for racing purposes}. I would only want bubbless tank.

Thinks to all that helped.

Kevin

Jim Duda

This has nothing to do with your tank problem but what engine and pipe are you using? Are you competing in F3D?

Ed Smith

You need to change your attitude. That is not a dumb idea. From a production standpoint it is a very good idea. The tank manufacturer offers the tank in two configurations, clunk tank or bubbleless. If you do not have the knowledge to know what you want, that is your problem, not the tank manufacturers.

Go here and explore the site. It may, just may dilute your ignorance. www.centralhobbies.com

Ed S

burgster

My Feedback: (2)

Ed,
You Rule!

Jeff

DHG

My Feedback: (7)

When Pat Morita died, he came back as Ed.

"Snatch the glow plug from my hand, Grasshoppa."

DHG

My Feedback: (7)

Or should it be "grow prug"?

SSGSPEEDMAN

the engine setup I have is MB engine, NEW CNC pipe from Big Bruce Racing, and prop size is 6.601x7.75.

Kevin

SSGSPEEDMAN

Like i said if you read,
It would be a dumb idea if you use a universal tank in racing.
In my case F3D. I didn't say it wouldn't be a good idea for production and it would be a GREAT idea. But don't assume other peoples motives if you don't know the whole persons point of view.

Kevin

Ed Smith

Now this is getting interesting. I am really interested in the prop dia 6.601". All the years we ran the Nelson F3D motor we never came down to that small of a diameter. 7.3 was an average and we played with the pitch. The Nelson did not have the power of the current MB so I am interested to see what the results are with that size prop on the more powerfull MB.

Ed S

SSGSPEEDMAN

The props im using are from big bruce racing.
the range of props I'm going to use are 6.550'', 6.600'', 6.650''. and 6.700''. It will all depend on the weather what prop I will use on that day. I use an accurate 12'' digital caliper to make my measurements.

I forgot to mention I use the MB Profi. Not the rear venturi MB.

Kevin

garys

Ed, the current props for the MB's are considerably shorter now that were run just a few years ago. The props I got from the Netherlands (Marcel Huisman) just before the team trials were right at 6.5".

Kevin, I believe your tank issue is coming from having the extra lines and not evacuating the tank of all air before filling it. I know you're using a vent to help, but there's a reason no pylon racer that I know of is using the tank with that line configuration. I've attached a pic of my Evo's front end. The line to the venturi comes out just behind the firewall and has a coupler that I disconnect to evacuate the tank and fill it. The pressure line comes out just forward of the wing, and connects to the pipe there.

Also, out of curiosity, it appears you're new to purpose-built racing planes (meaning not sport planes that are racing), why did you start with an F3D airplane when there's only been one race every couple years in the US?