How do I set up my bubbleless fuel tank?
10-15-2006, 05:00 PM
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How do I set up my bubbleless fuel tank?
Hey Guys,
Sorry for the ignorance, but this is my 1st time dealing with bubble less tanks. The instructions seem to be translated into English from Japanese and are subsequently not clear. It seems that they are telling me to have one line to the fuel pick up, and that one seems to just go straight in and protect it with fuel line as to not puncture the bladder. How far in should I go? They also have the muffler return to the outside of the bladder to provide positive pressure. That I understand. Now the part that confuses me is that they also have a third line inside the bladder for filling the tank. In the picture it is toward the top of the tank. I was under the impression that there was just 2 lines like a normal tank. Can't I fill through the carb line? Feel free to be very detailed if you are able to reply. I need a step by step. Your help is much appreciated.
Rob
Sorry for the ignorance, but this is my 1st time dealing with bubble less tanks. The instructions seem to be translated into English from Japanese and are subsequently not clear. It seems that they are telling me to have one line to the fuel pick up, and that one seems to just go straight in and protect it with fuel line as to not puncture the bladder. How far in should I go? They also have the muffler return to the outside of the bladder to provide positive pressure. That I understand. Now the part that confuses me is that they also have a third line inside the bladder for filling the tank. In the picture it is toward the top of the tank. I was under the impression that there was just 2 lines like a normal tank. Can't I fill through the carb line? Feel free to be very detailed if you are able to reply. I need a step by step. Your help is much appreciated.
Rob
10-15-2006, 07:20 PM
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RE: How do I set up my bubbleless fuel tank?
I think this post is better over on the engine sectin not on the twin section. I have used the Tetra and home made bubbleless tank. I use the two line system although I have seen the diagram on the box from Tettra.
Place the pick up at about the mid point of the tank.
To fill you must suck the air out first. Then put fuel into the tank. I use a very large about 12 oz syringe to do this I think I got mine from Jett ($39). My tank capacity was about 6.5 oz so I would put about 7 oz in my syringe then draw the air out of the tank then turn the syringe over so there isn't any air and carfully push the fuel into the tank. Doing this slowly by hand you will feel when the tank is full remember you are not trying to blow it up like a ballon under pressue but to fill the bag. When you think the tank is full. Carefully disconnesct the fuel feed line and I always held the plane verticle for this step and I allowed any residule pressue in the tank to bleed off. Then I would pich off the line (hemostat) and hook it up to the engine.
Leave the fuel line pinched off until ready to start. Frequently I could get the plane started before I took the hemostat off.
What application are you using the tank in?
Hope this helps. I used the system extensively in my RC Combat planes it works very well in making consistent engine runs from full to an empty tanks in a high G enviroment.
Good enough for me to be the 2000 RCCA class 2105 National season point champion.
Sparky
Place the pick up at about the mid point of the tank.
To fill you must suck the air out first. Then put fuel into the tank. I use a very large about 12 oz syringe to do this I think I got mine from Jett ($39). My tank capacity was about 6.5 oz so I would put about 7 oz in my syringe then draw the air out of the tank then turn the syringe over so there isn't any air and carfully push the fuel into the tank. Doing this slowly by hand you will feel when the tank is full remember you are not trying to blow it up like a ballon under pressue but to fill the bag. When you think the tank is full. Carefully disconnesct the fuel feed line and I always held the plane verticle for this step and I allowed any residule pressue in the tank to bleed off. Then I would pich off the line (hemostat) and hook it up to the engine.
Leave the fuel line pinched off until ready to start. Frequently I could get the plane started before I took the hemostat off.
What application are you using the tank in?
Hope this helps. I used the system extensively in my RC Combat planes it works very well in making consistent engine runs from full to an empty tanks in a high G enviroment.
Good enough for me to be the 2000 RCCA class 2105 National season point champion.
Sparky
10-15-2006, 11:53 PM
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RE: How do I set up my bubbleless fuel tank?
Thanks for the response. That information is very helpful. I am using bubble less tanks on my four engine trainer kit bash. I was told that with four engines all vibrating at the same time. I was going to get foaming in my tanks, unless I padded the tanks very well, or used bubble less tanks. I found that the bubble less tanks took up less room. Thanks for the tip about pinching off the line to the carb. Guess I'm going to need 4 small hemostats. Is it bad to use a push type refueling probe with a bubble less tank? Thanks again!
Rob
Rob
10-16-2006, 12:04 AM
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RE: How do I set up my bubbleless fuel tank?
ORIGINAL: roofus4
Thanks for the response. That information is very helpful. I am using bubble less tanks on my four engine trainer kit bash. I was told that with four engines all vibrating at the same time. I was going to get foaming in my tanks, unless I padded the tanks very well, or used bubble less tanks. I found that the bubble less tanks took up less room. Thanks for the tip about pinching off the line to the carb. Guess I'm going to need 4 small hemostats. Is it bad to use a push type refueling probe with a bubble less tank? Thanks again!
Rob
Thanks for the response. That information is very helpful. I am using bubble less tanks on my four engine trainer kit bash. I was told that with four engines all vibrating at the same time. I was going to get foaming in my tanks, unless I padded the tanks very well, or used bubble less tanks. I found that the bubble less tanks took up less room. Thanks for the tip about pinching off the line to the carb. Guess I'm going to need 4 small hemostats. Is it bad to use a push type refueling probe with a bubble less tank? Thanks again!
Rob
-----------
If you have any pictures of said four engine trainer, I sure would love to see them. I'm not fussy over appearance. I'm interested in the engineering. TIA
10-16-2006, 11:10 AM
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RE: How do I set up my bubbleless fuel tank?
ORIGINAL: roofus4
Hey Guys,
Sorry for the ignorance, but this is my 1st time dealing with bubble less tanks. The instructions seem to be translated into English from Japanese and are subsequently not clear. It seems that they are telling me to have one line to the fuel pick up, and that one seems to just go straight in and protect it with fuel line as to not puncture the bladder. How far in should I go? They also have the muffler return to the outside of the bladder to provide positive pressure. That I understand. Now the part that confuses me is that they also have a third line inside the bladder for filling the tank. In the picture it is toward the top of the tank. I was under the impression that there was just 2 lines like a normal tank. Can't I fill through the carb line? Feel free to be very detailed if you are able to reply. I need a step by step. Your help is much appreciated.
Rob
Hey Guys,
Sorry for the ignorance, but this is my 1st time dealing with bubble less tanks. The instructions seem to be translated into English from Japanese and are subsequently not clear. It seems that they are telling me to have one line to the fuel pick up, and that one seems to just go straight in and protect it with fuel line as to not puncture the bladder. How far in should I go? They also have the muffler return to the outside of the bladder to provide positive pressure. That I understand. Now the part that confuses me is that they also have a third line inside the bladder for filling the tank. In the picture it is toward the top of the tank. I was under the impression that there was just 2 lines like a normal tank. Can't I fill through the carb line? Feel free to be very detailed if you are able to reply. I need a step by step. Your help is much appreciated.
Rob
You can use a 3rd line for fill, but I do not recommend it. It make it more difficult to get all of the air out of the tank during the fueling operation. Evacuate and fill the tank using the feed line to the engine.
The pressure side goes to the muffler. As with a conventional setup. Except with the bubble tank you are only pressurizing the outside of the fuel bladder.
For reference, the operating and setup instructions for the Bubble-Jett tanks are similar to the proceedure required for a Tetra tank (except you do not have to assemble the tank) http://www.jettengineering.com/tech/techbubjet.html
I hope this is helpful
Bob
10-16-2006, 11:13 AM
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RE: How do I set up my bubbleless fuel tank?
ORIGINAL: roofus4
Thanks for the response. That information is very helpful. I am using bubble less tanks on my four engine trainer kit bash. I was told that with four engines all vibrating at the same time. I was going to get foaming in my tanks, unless I padded the tanks very well, or used bubble less tanks. I found that the bubble less tanks took up less room. Thanks for the tip about pinching off the line to the carb. Guess I'm going to need 4 small hemostats. Is it bad to use a push type refueling probe with a bubble less tank? Thanks again!
Rob
Thanks for the response. That information is very helpful. I am using bubble less tanks on my four engine trainer kit bash. I was told that with four engines all vibrating at the same time. I was going to get foaming in my tanks, unless I padded the tanks very well, or used bubble less tanks. I found that the bubble less tanks took up less room. Thanks for the tip about pinching off the line to the carb. Guess I'm going to need 4 small hemostats. Is it bad to use a push type refueling probe with a bubble less tank? Thanks again!
Rob
Bubbleless tanks rock, you may fall in love with them. Fueling is no more trouble than a conventional tank once you get the hang of it, and you'll sure like the consistent engine runs.
MJD
10-16-2006, 02:14 PM
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RE: How do I set up my bubbleless fuel tank?
Thanks for all the info and the great ideas. I like the idea of a blocked off nipple to store the line on untill ready to go. Any thoughts on using a refueling port? Artisan, here are some pics that you were curious about. It is a Hobbistar 60.
10-17-2006, 09:53 AM
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RE: How do I set up my bubbleless fuel tank?
Very nice project !! Cant wait to see it when done !
I have in the past used the dubro fueler valve with a bubble-jett tank. I do not recommend it. Even with the tanker, it was more hassle than it was worth, and added a leak source in the process.
After you evacuate the tank of air, you have to either clamp the line while switching to a full syringe for filling, or immeidately fill it if using something similar to the Jett Tanker. Any open line after evauating the tank will permit air to enter the tank. At that point, you will have problems.
I have in the past used the dubro fueler valve with a bubble-jett tank. I do not recommend it. Even with the tanker, it was more hassle than it was worth, and added a leak source in the process.
After you evacuate the tank of air, you have to either clamp the line while switching to a full syringe for filling, or immeidately fill it if using something similar to the Jett Tanker. Any open line after evauating the tank will permit air to enter the tank. At that point, you will have problems.
10-17-2006, 10:00 AM
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RE: How do I set up my bubbleless fuel tank?
Thanks for posting the pics, Roofus. That is a neat design. I hope you'll post the results in RCU, or, better yet, PM them to me. I love multi engine models. Especially ones that aren't patterned after a full size design.
You do nice work, no doubt.
You do nice work, no doubt.
10-17-2006, 10:18 AM
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RE: How do I set up my bubbleless fuel tank?
Rob,
Hemostats are the way to go. Your setup isn't scale so have easy access to the fuel feed line and when you get the tank fueled. Bleed off the residual pressure and clamp it off. The reason I held my plane vertically during this is that the tank is like an open bottle laid on its side the fuel will flow out of the tank by gravity. So if fuel flowed out of the tank with the plane held verticaly it had residual pressure.
Have your helper during start just release the hemostat as the engine fires and it will continue to run just fine. That is the way I did my one engine on my combat plane and it worked flawlessly. If you pull the hemostate from the engine early it will tend to flood since like I said the tank is like a bottle laid on its side and fuel will try to flow particulary if you are trying to start multiple engines and working the throttle to get all the engines started in rapid order.
What size engines and what size tanks are you using? It is very easy to make your own bladder tanks and a lot more cost effective. I used the Playtex disposable babby bottle bags. I could get around 6.5 oz in one and put it in a 8oz tank.
About the only thing you might consider since you will need to hold the plane verticaly is putting a stick out the back of the fuse so that you don't damage the tail feathers from an inattentive holder who may brush the ground with the tail.
Sparky
Hemostats are the way to go. Your setup isn't scale so have easy access to the fuel feed line and when you get the tank fueled. Bleed off the residual pressure and clamp it off. The reason I held my plane vertically during this is that the tank is like an open bottle laid on its side the fuel will flow out of the tank by gravity. So if fuel flowed out of the tank with the plane held verticaly it had residual pressure.
Have your helper during start just release the hemostat as the engine fires and it will continue to run just fine. That is the way I did my one engine on my combat plane and it worked flawlessly. If you pull the hemostate from the engine early it will tend to flood since like I said the tank is like a bottle laid on its side and fuel will try to flow particulary if you are trying to start multiple engines and working the throttle to get all the engines started in rapid order.
What size engines and what size tanks are you using? It is very easy to make your own bladder tanks and a lot more cost effective. I used the Playtex disposable babby bottle bags. I could get around 6.5 oz in one and put it in a 8oz tank.
About the only thing you might consider since you will need to hold the plane verticaly is putting a stick out the back of the fuse so that you don't damage the tail feathers from an inattentive holder who may brush the ground with the tail.
Sparky
10-17-2006, 07:52 PM
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RE: How do I set up my bubbleless fuel tank?
The tail looks much to weak in that airplane [sm=thumbs_down.gif]. With 4 engines and a conventional tail, it would be weak. With the rudders out on the ends of the horizontal stabilizers it will be constantly breaking. Ground damage will be a problem. Given the size and weight of the rudders it looks as it might break off in flight [:@] I like multi engine airplanes, they look and sound cool, but I think this one is doomed to failure. You would have better off to just go with a larger single rudder in the middle. Putting rudders on the ends of the horizontal stab introduces all sorts of structural and flutter problems.
JettPilot
JettPilot
10-17-2006, 07:58 PM
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RE: How do I set up my bubbleless fuel tank?
Rob,
i looked at the picture and I agree with the Jettpilot. A multi will have all sorts of harmonics after all that is why you are going with the bubbless tanks. At a minimum sheet the stab with 1/16 balsa top and bottom. Central vert stab would be the best choice as he said.
Sparky
i looked at the picture and I agree with the Jettpilot. A multi will have all sorts of harmonics after all that is why you are going with the bubbless tanks. At a minimum sheet the stab with 1/16 balsa top and bottom. Central vert stab would be the best choice as he said.
Sparky
