Newbie needs a bubblesstank??

Newbie needs a bubblesstank??
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Newbie needs a bubblesstank?? - 4/7/2002 2:40:51 AM

Posts: 61
Joined: 4/7/2002
From: Randolph, MA, USA
Status: offline

Hello...
The scat cat and the viper last year has got me going on this go fast and turn left thing....too cool...
The SIg wonder with an HB .25 goes pretty good as well.
I am seeing all these refernces to "bubblesstanks" and was told as local field this is the thing to have for pylon ...??

Is there any local available in the MA area?
Need 4oz,6oz ??
ANy help would be great..
Thanks
Ken aka Crashland
AMA17739

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Newbie needs a bubblesstank?? - 4/7/2002 4:55:49 AM

Posts: 1346
Joined: 12/29/2001
From: Monroe, NC, USA
Status: offline

There are two brands of bubbleless tanks. The Tettra which is sold by [URL=http://www.pspec.com/]Performance Specialties[/URL], [URL=http://www.darrolcady.com/]Darrol Cady R/C[/URL], and [URL=http://www.centralhobbies.com/]Central Hobbies[/URL]. The Tettras are available in a wider range of sizes than the [URL=http://www.jettengineering.com/]JETT Engineering[/URL], but the Jett's are very good tanks. Dub has a tech article on using the [URL=http://www.jettengineering.com/tech/techbubjet.html]bubbleless[/URL] tanks that you should read.

You can also make them yourself using a baby bottle liner. Ask if you want to know how. I recommend you buy a few first.

Check out [URL=http://www.pylonworld.com/rc_pylon/q-500/q-500_accessories.htm]Q-500 Accessories[/URL] on PylonWorld.com for more stuff you may be interested in, especially the Horizon Hobby - Fuel Shutoff clips.

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RCPRO Chairman of the Board

(in reply to crashland)

Newbie needs a bubblesstank?? - 4/8/2002 7:01:10 AM

Posts: 61
Joined: 4/7/2002
From: Randolph, MA, USA
Status: offline

Great info, perfect for the questions i have.
I see some differences in teh tanks, but one indicates that theirs is prebuilt, the Jett version. This looks good for a time saver....

But at a loss for what seems to be a must , is the "gun" to fill the tank with and the clamp of whatever sort to keep the air out.
Is this the only way to fill the tanks>>??

All great stuff.. need to get to a local meet here in MA nda ask some more questions before I finish the two new plyon toys...
Thanks for your help.

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Soft Landings

(in reply to crashland)

Syringe - 4/8/2002 7:26:08 AM

daven

Posts: 7004
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline

You really need a syringe to fuel the bubbleless tanks. You suck out all the air in the bladder, and then fill with raw fuel.

This will completely take all air out of the equation. I like the Jett Tanker the best. You can order it when you order your tanks.

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Dave Norman

klasskote.com
supertrc.com

(in reply to crashland)

Newbie needs a bubblesstank?? - 4/8/2002 7:57:06 AM

Posts: 1346
Joined: 12/29/2001
From: Monroe, NC, USA
Status: offline

The fuel line goes into the bladder that is inside the tank. The end of the fuel line (the inside part is the pickup line) has a notch so that as the engine pulls the fuel out, the end the pickup line doesn't get blocked. The pressure from the muffler pressurizes the space between the tank and the bladder, hopefully with no leakage in the bladder.

The key to bubble-less-ness is to make sure there is no air that the engine can pull out of the tank. To do this, you suck all of the fuel (and air) out of the tank bladder. You do it by feel, because you can't see the tank. When all fuel and air have been removed from the bladder, it is completely collapsed. You then need to fill the bladder until it occupies no more than the available space between the tank and bladder. If you use too much pressure, you will rupture the bladder. So once again, it is a feel thing. When you have put the fuel into the bladder, you need to clamp the fuel line off for a couple of reasons. If you don't clamp it, air will enter the bladder unless it is 100.00% full, which is why you are careful when you put the fuel in. Another thing is that the weight of the fuel above the pickup line will force fuel out and the siphon effect will empty the tank. Even if you pinch the fuel line and plug it into the carb, fuel will siphon out, and/or air will enter the system.

So after fueling, you've got to pinch the tubing until you are ready to start the engine. Actually, until you are starting the engine, because you don't want to flood the engine and you don't want air to creep back into the tank. Hemostats can be used, or an inline fuel shutoff clip can be used. Hemostats bang around as you carry the plane to the line, etc, and are easy to loose, or drop into the prop, etc. You want to pinch the tubing as close as possible to what you are going to be plugging it into, usually a Remote Needle Valve these days. For that reason many people use an inline fuel shutoff clip. You can see some at [URL=http://www.horizonhobby.com/products/description.asp?prod=KSJ221&pc=KSJ221]Fuel Shutoff Clips[/URL]. Some people make their own out of aluminum or other materials that can be non-abrading.

The Jett Tanker is purpose made for the job, and even with that, it still needs an O-ring overhaul every so often. If you use a syringe, it's got to be a big one. And if it's not big enough, you can't feel with the sensitivity you need. You may be able to buy a big veterinarian syringe, but the plunger probably won't hold up to fuel, for long anyway.

You don't want to get a rupture in the bladder because fuel will leak into the space that should be pressurized. Because the pickup line does not have any kind of clunk on it, you will not get a full tank out via the pickup line. The tank will contain the fuel, but the engine won't be able to get it. So the Tanker is the ticket.

BTW, bubbleless tanks are great for all kinds of planes. No bubbles mean better and more consistent engine runs, plus engines are damaged by air in the line. Think of them as little bursts of way too lean settings.

One other thing, get the tank and the tanker at the same time. That way you can practice while you can see what is going on in the tank before you put in it the plane.

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Don Stegall
RCPRO Chairman of the Board

(in reply to crashland)

Newbie needs a bubblesstank?? - 4/8/2002 4:58:28 PM

Posts: 2851
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline

For Gun Read "Syringe"

In additin to what has alredy been written. The syringe that Jett sells is big enough to carry out the whole procedure without disconnecting. The syringe is half filled with fuel, then connected to the fuel line of the tank. The air is then sucked out of the tank with the other half of the syringe capacity, the fuel is then pushed into the tank. Then clip the line and connect to the engine.

When filling have patience. I have seen peoples arms trembling with the force of trying to fill the tank. They seem to forget that they are trying to force an 1 1/2" dia of fuel in the syringe down a 1/16 dia hole in the fuel line. There is no pressure in the tank so all that is required is a gentle pressure on the syringe.

Ed S

(in reply to crashland)

Newbie needs a bubblesstank?? - 4/14/2002 2:57:49 AM

Posts: 61
Joined: 4/7/2002
From: Randolph, MA, USA
Status: offline

This is a great place to learn.....

So after looking at all the tanks and being lazy... the Jett ones look good.
ALso the syringe will be a nice addition to the field kit, this looks to be that the extra money for the fancy "O" rings and the larger tubing is a welcome upgrade and only is money....

Thanks
Ken

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Soft Landings

(in reply to crashland)

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