Guys ive had an idea and would like to know if any one else has done this or if it is even at all possible.

Basically instead of routing vent lines to an outlet on the models surface under the fuse or where ever, Can you route a vent to another very small empty fuel tank inside the model which is in itself open to the atmosphere via an uncapped fitting in the bung?
Hope you understand what i mean, its basically the same idea as a fluid catch/overflow tank as used in various motorsports etc.

This way you can keep the vent/overflow inside the model, thus helping the scale appearance without any fear of mess to clean up.

You could do that but you would still need somewhere to connect your "Taxi" tank to the fuel system.

Bob

So you fill your model with fuel, and the last "overflow" goes into this "inside" tank. And then as your fuel tanks that you filled, swell cause it's hot outside, the fuel from the other tanks purges into this "inside" tank. And then that fuel goes out the hole in your bung in that "inside" tank, and I just want to be sure I've got this figured out...........

YOU HAVE NO FEAR OF A MESS TO CLEAN UP!

I'm not aware of any fueling system that is accurate enough to handle what you are referring to.

Sean thats exactly the point, It will act as a fluid catch tank. I know i would rather most of the expelled kero to end up in something like this than wind swept along the side of that paint job i just finshed. Like i said it was just an idea.

Just for giggles, have you ever tried to fill your main tanks without spilling out of them? My point is, what makes you think that if you can fill "just" your main tanks, that you can do any better on the last tank?

You need to expel to the outside of the airplane, unless you have some super power that allows you to control fluid overspill that I am unaware of.

Sean no super powers here bud.
At present yeah, i do have my vent lines fixed to the bottom of the fuse and you are quite right that it would be nearly impossible to stop any spillage il admit that.
I was just getting opinions on an idea. If it turns out to be a naff one then il be more than happy to stick with the more conventional setup.

FWIW, A friend of mine dropped a vent line down through the opening where the gear door is. It's just zip tied to the side of the fuse, just inside the door. Your concept is sound, your method is not.

Just wanted to give you some grief before I gave you a solution. [8D]

Yes that is fine from a physics perspective, not so sure about it's "real world" practicality, however.

You would have to make sure that this inside "catch tank" is big enough to do the job (you said the tank would be "very small" so you have to be careful there). Being "big enough" to do the job is the overriding issue here. If the internal catch tank is too small then you run the chance of overflowing the fuel into the inside of your model (either upon filling the tanks or at some point while flying the model due to fuel sloshing, expansion/contraction of the tanks, etc.).

IMHO, if you have that much room in the model, then you should just use that internal "catch tank" as another fuel tank to have more usable fuel to burn in the air, and again move the "catch" tank (or "taxi tank" so to speak) and the final "vent" to the outside of the model. Nothing to be gained by flying around with the catch tank on board.

Hope that helps,

Ok thanks both of you for your input. Space, as you have said Matt would be my main issue here. Ive probably got room for another 500-600ml tank at most.

Hello again,

Never in my wildest dreams would I leave a 500 ml tank empty in a plane!! But that is just me!!

Matt, you aren't alone, and I don't even know what a Ml is but if he's talking about a 16 ounce tank, I'd say fill that baby up! Even if it's behind CG, you have it as your last tank, and your airplane will be well balanced for takeoff, and become more nose heavy as the flight goes on, and then come back go CG for landing. I have done this with great success (so long as you are truly counterbalancing against the fuel ahead of CG)

Why would you want to carry fuel onboard that you cant use? Just extra weight. I would rather use the overflow tank for more fuel to burn for more time to fly.

Not possible here mate, the only extra space i have is directly above the two tanks already in the model. If the 'catch tank' didnt totally overflow during flight anyway i thought you may be able to siphon out whats left in it and use it for the next flight instead of it being wasted by being totally expelled.
Any how i think il just resign this idea to the garbage can

Hello again,

Don't be put off by the responses, it is not a bad idea at all. if you saw some of the stuff I sit and fixate over you would see some truly bad ideas I can assure you (try a wet drop tank with a parachute, I will never forgive Kevin W for putting that bad idea in my head!).

Remember no matter what anyone says, they are all toys, a year ago I spent a couple of weeks on this guy and he is STILL waiting to get in a flight!!!

http://www.mattcarroll.com/jetjoe/JetJoe.avi

Why not just have a small length of 3mm brass tubing out the bottom of the fuse and then, when filling, push a 3mm festo onto this brass tube and run a length of tube back into your fuel cannister.

No faffing with extra tanks, no super human powers needed, no trying to beat physics and no fuel on your paint job?! [8D]

Rgds,
Mark

A Cowell,
You have a unique idea that made me really think. I believe it would work fine maybe using a 6 or 8oz size tank with a clunk setup. The kero residue i have on the belly of my jets adds to the realism but i could do with out it...

V..

I've see a few people do as described and simply called it 'An Onboard Taxi/Startup Tank' but like everyone else, if it's onboard, I'd be using it for in flight fuel. the only advantage of the onboard taxi tank is it can be mounted well aft of the CG.

I did basically the same thing (except glued, not zip-tied) on my Hunter. When the clamshell door closes, the vent line is hidden yet is still far enough away from the door to allow air to be drawn freely (don't want a flameout due to fuel starvation when you pull the gear up !). Aircraft sits on the ground with the doors open, so any drips will not go inside the aircraft.

Gordon

exactly the idea i had in mind for this issue as well !

Isnt a fuel dump a scale feature?
Scott

Matt, I can't believe you don't have his eyes blinking. You need to put a couple more weeks in on him.

I love that guy...need to go in Billy's A-10...or strap him to the top of your little hotray.

PR

Hey, mine worked! LMAO


I wasn't sure why I was clicking on this thread, but something told me I should. Now I know why!

He hasn't flown yet??????????????????????????? I can't believe it!!

I guess it helps if you actually know what you are doing!

What does NOT work is staring at it for weeks...ugh

my builder is taking his sweet time.