nonstoprc

My Feedback: (90)

I would stick with the gas for various reasons (readily available, cheaper, more power etc). Find a fix to the smell problem probably is very possible. I just need to find a air-tight container for the gas can.

ChopperMike

Oh man, here we go again. This will open up a whole 'nother can of worms.

Not a good solution. As I said a few posts ago, I looked into using Coleman fuel as a solution to the smell problem and almost everyone who replied said not to use it. It's octane is way too low to use as a motor fuel. Some are using it and getting away with it but if you use it you better hope you don't have an engine problem and that the mfg doesn't get wind of it as none of them approve of it's use.




Mike

dirtybird

My Feedback: (5)

The fuel pumps in cars are sealed with connectors that are not disconnected and reconnected while gas is around.
Gasoline is not more explosive than alcohol but it is a lot more volatile.

I had a leaky gas line leak on my exhaust pipe when my engine was running. It didn't ignite. I have been counting my lucky stars ever since

RCAddiction

My Feedback: (87)

Actually, I designed fuel systems for some of the most popular vehicles on the road. The post above about spade connectors is 100% correct. Further, the in tank pumps are DC brush motors, and the gasoline is pumped up through the center of the motor's spinning armature, thru/past the brushes/commutator, and out the top of the brush holder. The gasoline is actually used to cool the electric motor.

None of it blows up because there isn't enough oxygen present inside the fuel tank.

I use an electric fuel pump for my personal gas can. Of course, I don't use the Greylor pump like virtually everyone else does (Jersey Modelers, Fisher, etc, etc). I use a Facet automotive fuel pump which is designed to pump gasoline, and is intended to be mounted outside of a fuel tank.

Robotech

My Feedback: (9)

You're not supposed to smoke a cig when you pump gas? Oh.

w8ye

My Feedback: (16)

You are supposed to smoke the cigarette with it cupped in your hand and the back of your hand up where the gasoline cannot see it?

I suppose the gasoline cannot see the sparks from a switch either?

RCAddiction

My Feedback: (87)

If you design your pumping system so that the switch body is inside a sealed box, there is generally no issue when the switch contacts arc during switching. Most of the commercially sold units are done this way. The gas fumes have no incentive (pressure differential) to migrate into the box, or down thru the switch shaft, in sufficient quantities to cause an event.

The people who are at greater risk are those with a switch hanging out in the breeze. Those scare the crap out of me. Many of those get away with it simply because there is so much air movement out at the flying field that the gas vapor doesn't concentrate enough to become subject to ignition.

By the way, static discharge can be a bigger gasoline ignition problem than lighting a cigarette, simply because it's less obvious. Please fill your red gas cans from the gas station fuel pump when they are sitting on the ground. Never inside the back of your truck. Make sure that you and the tank are both grounded to the same ground plane.

JNorton

My Feedback: (2)

Thank you RCAddiction for the information on Faucet pumps.
Here is a link for those who are also interested. http://www.aircraftspruce.com/catalo...facetpumps.php
John

PS I'll enclose my switches.

RCAddiction

My Feedback: (87)

Here is the actual Facet pump I use. I believe I bought it at PepBoys or one of the other large retail chains several years back.

[link=http://www.facet-purolator.com/index.php?option=com_content&task=category&sectionid=7&id=13&Itemid=35]Facet Posi-Flo Fuel Pump[/link]

Please note that automotive fuel pumps, such as the Facet, are one-way pumps. You cannot use them in reverse to empty your tank. I arranged my plumbing to my gas tank so that I can connect the pump's outlet to the airplane to fill, and I can connect the pumps inlet to the airplane to empty.

The upside is that they are DESIGNED for gasoline. They prime NOW, there's no waiting for them to start sucking fuel like a gear pump. They last pretty much forever, don't leak, and they don't go boom.

dirtybird

My Feedback: (5)

When you use the Facet pump in a auto the switch is a long way from the gas tank that these days is sealed. If you use one for our gas engines fuel pump you still need an explosive proof switch to activate it near our vented gas cans.
A cheap reed switch is explosive proof if activated by a magnet.

RCAddiction

My Feedback: (87)

Actually, cars today are all high pressure fuel injected, typically at 35psi and higher. Those Facet pumps are primarily low pressure pumps used for older carbureted or throttle body EFI. And there's no "switch" per se, other than the vehicle's electrical system. The tanks today aren't sealed, although one might think they would be. If they were, the air could not enter the tank to allow the fuel to leave which is being pumped out. There's usually a rollover valve connected to a charcoal canister connected to the top of the tank. It's open to atmosphere, and in the event the car rolls over, the valve seals so fuel doesn't pour out of the car, minimizing the chance of a fire.

But your point is well taken. Explosion proof switches are a desireable option. They are incredibly expensive, though. A magnet operated reed switch is a good idea. I've not seen any reed switch that can handle the current draw of these pumps, but perhaps they do exist. However, you could build a circuit using a reed switch as the trigger to operate a solid state switch which itself could handle the current draw.

dirtybird

My Feedback: (5)

OK the gas tank is not sealed. But the purpose of that carbon canister is to prevent gasoline vapor to escape in the atmosphere.
If you are going to use a solid state SW you probably wouldn't need a reed sw. I have a Darlington connected pair that has a 5A inductive rating and a gain of 40K. You could trigger that with 1ma.
The point is this is an area a hobby builder should not be playing with. He could get himself killed.
This is where you should get an ARF so to speak.

RCAddiction

My Feedback: (87)

I cannot disagree.

Some of the electric fuelers posted over the past couple of years frighten me, because I know the components and failure modes...but I'm not going to police others. If it concerns you, don't do it. I've designed and developed fuel systems and ran a fuel lab. So....not terribly worried about my own stuff, since I've learned how not to blow myself up.....which is why I've selected the components I use.....more worried about what others do.

With their flaws, electric-powered gas cans are still probably no more dangerous than many other aspects of our hobby, which is fraught with similar perils....like flipping a 32x10 carbon fiber prop by hand, though probably safer than hovering a 40% or a large heli in front of oneself, or overtaxxing a LiPo battery..... The good news is that these fuelers are generally used outside, and the risk of a high fuel concentration is quite low. Otherwise some of the sloppy stuff people have done would have already gone boom.

Really Dangerous? - people charging a Lipo in their plane, near a 2.5 gallon jug of gas or gallon jug of glow fuel, while driving enroute to the field.

tailskid

My Feedback: (34)

"people charging a Lipo in their plane, near a 2.5 gallon jug of gas or gallon jug of glow fuel, while driving enroute to the field."

We aren't? Gee you learn something every day

RCAddiction

My Feedback: (87)

I've seen it done.

dirtybird

My Feedback: (5)

I don't believe in dismissing actions just because other people do dumb things.

When I flew big gas engines I used a simple gas can and set it on a table over my airplane and let the fuel drain in. When I wanted to defuel I set the can under the airplane and let it drain out. Simple, cheap and it works. It took a little longer but it gave me time to yak to my friends

JNorton

My Feedback: (2)

I'll just use a sealed rocker switch mounted in an aluminum mini box with the Facet pump.
John

nonstoprc

My Feedback: (90)

I tested a 5-gallon plastic paint pail today as an air-tight container for the gas can, with the pail sitting in the car for over 8 hours and the outside ambient temp is 102 degrees.

It worked beautifully. No gas smell at all!

GreaTOne_65

Rangerfredbob, your post reminded me of a story my FIL told when he was a crew chief in WWll. He was a crew chief and was responsible for a P-40, which most everyone knows was powered by the Allison engine which was known as an oil leaker. Well the guys came up with a cure, because if any oil was found on the ground, it intailed a complete tear down of the engine, a couple of weeks job, in the Florida heat. So what was the cure? Well when the plane was taxied up to the hard stand and the ignition was switched off, as soon as the propeller quit turning, the crew chief's were ready with a 5 gallon can of gasoline, which they promptly threw into the air intake! How about that? Even though the engine was hot, as long as there wasn't a spark some where, no problem.

I built my portable gas/smoke tanks, over 20 years ago. Both cans are 1 gallon metal cans, one on each side of a lawn mower 12V battery, in a wooden tray. The electric pump I bought from Carquest, it's an in-line gas pump for an automotive application. I wore one out, and bought another one which has been working flawlessly, I use a push-button switch, which makes it easy to turn off and on to top off the tanks. If there is any draw back, I can't draw the fuel out of the plane, if I need to defuel it I use a brake line bleeder.

Dale

JNorton

My Feedback: (2)

GreaTOne_65

Well if you want to talk about insane. My family was in the garage business when I was a kid. I've seen my father brazing a gas tank shut with the gas from the leak dripping down and flaming on the ground. As long as the gas tank was full so there were no vapors he claimed there would be no explosion. My uncle had a fuel can and kept the tank full while Dad was brazing. There is absolutely no amount of money that would convince me to try this. Yet I know they did it more than once.

John

andy9

I'm having second thoughts of buying a new no spill fuel cans that I saw online. I think it's gonna be really great but I need your opinions.

thevirginian

Jezmo, I have to disagree with you on that one. Although very true that both, gasoline and alcohol are both very falmmable, there is a big difference in their evaporation points. Gasoline evaporates at much lower temps, which makes it so much more volatile. BTW, not the liquid gasoline or alcohol is flammable, but their vapors. Actually you can extinquish a cigarette butt in gasoline or alcohol without igniting the liquid itself. And since gasoline evaborates so quickly there is always a great risk of an ignition by an electrical spark such as a bad battery connection. Electrical pumps and glow fuel pose a much smaller risk, because of the higher evaporation point of alcohol.

nonstoprc

My Feedback: (90)

Sounds like a leaked gas tank inside the airplane can allow vapors to accumulate inside the fuse and be ignited by on-board power switches, if the switches are not sealed.

I have been using electric pump for glow fuel and never have a problem.

Jezmo

You are quite welcome to dissagree kind sir. The point of my conversation is the potential ignition of the fuel at normal temps under which plenty of alcohol vapors will be present to ignite just as with gasoline. I commented that the only accident witnessed in my 45+ years of working with model fuels happened to be with glow fuel. (As I stated the young man was severly burned.) I have been flying giant scale gassers now for almost 25 yrs and by no means am I saying that an accident can't occur using an electric pump for gasoline, it's just that I haven't witnessed any in that very long time. You probably have a better chance of getting seriously injured in an auto accident than getting hurt by an electric fueler setup. In that same amount of time I have personally witnessed dozens of serious auto accidents (some fatal) and that doesn't stop us from driving. Again, it is my humble opinion that one has a greater chance of getting whacked in traffic by a driver talking on a cell phone than by some freak accident using a battery powered fueling system.

thevirginian

nonstoprc;
You are absolutely correct. It could happen. If all factors are in favor of an ignition an explosion could result. Luckily there is a very slim chance of an electrical spark inside the fuse unless you unplug a battery. There also needs to be an accummulation of gasoline vapors inside the fuse, that cannot escape. If there wouldn't be an elevated risk with gas engines, why would we need to have a fire extinquisher handy?