Spare gas vs. "drop tanks."

[Martinjmpr]

The gas can discussion below prompted me to think about how I use my spare gas can. Thought I'd see if anyone else does what I do.

When I was a kid, like many kids I started getting interested in things related to airplanes, especially WWII fighter planes. I noticed right away that often times they'd have teardrop shaped pods under the wings. When I read a little more I found out these were extra fuel tanks.

Now at first I thought "that's the stupidest thing in the world! If they get into a fight with an enemy aircraft, the first thing the enemy is going to do is try to shoot at their fuel tanks!"

But of course, I was the one who was stupid (really just ignorant) because I didn't realize how they used those fuel tanks: They were "drop tanks" and the idea was that they'd take off from their (presumably secure) base in England or France or Guadalcanal or New Guinea or wherever, and they'd use the fuel from the drop tanks. Then, either when the fuel in the drop tanks ran out, or when they sighted enemy planes, they'd pull a lever and drop the tanks and at that point they'd use the "internal" fuel tanks built into the plane.

When I went to the Maze District last year my original plan had me spending at least 2 days away from any sources of fuel. With only 18.5 gallons, I was a bit worried about my Tacoma being able to go the distance.

On the other hand, I didn't have any external mounting points for fuel cans, and for that matter I didn't own any fuel cans at all other than one of those 5 gallon plastic "blitz" cans. I know those aren't the most rugged cans and since my cargo compartment is also my sleeping compartment, the last thing I wanted was to have gas sloshing around there.

So, I figured I'd use my plastic can as a kind of "drop tank." What I did was this: When I filled up with gas in Green River (last gas stop for a couple of days), I filled both my tank and the can. Figuring that I typically get around 18-21 MPG, my estimate was that 5 gallons would get me ~110 miles.

So, I carefully placed the full gas can (inside a heavy plastic bag) in the back of the truck and drove off. I watched the trip odometer and that night, when I made camp, I noted that I had put around 120 miles onto the truck since filling up. At that point, I emptied the 5 gallon can into the tank, figuring that it was safer, cleaner, and just generally easier to carry my "extra" fuel that way rather than have it sitting in the can. After I emptied the can, I opened it up to let it vent and let it sit out all night. Next morning I capped it, wrapped it up in the plastic bag and taped the bag securely shut (from that point on I knew I would be hitting a gas station at least once a day.)

There are a lot of good reasons for carrying extra gas in a can (for one thing, that makes it easy to offer to a buddy or stranded traveler without risking the mouthful of gas you could get using a siphon hose) but for me, using the "drop tank" method was easier and more convenient. I still got the benefit of the extra gas - in effect, it gave me a 23 gallon tank - but I didn't have to worry about a full fuel can bouncing around in the back of the truck, nor did I have to worry about leaks, fumes, etc.

Just wondering if I'm the only one who uses my spare gas cans this way? Does everyone else just leave them full until/unless they're needed?

 

[Pskhaat]

Nope, I always employ the spare fuel up-front. 5 gallons would probably get me a whopping 50 miles in the Maze though

 

[paulj]

I remember raising the question of whether to use fuel cans early in trip or later (if at all) a couple of years ago when planning a trip in eastern Oregon. I was planning on carrying a couple of small plastic cans in the roof box. As it turned out, I never filled the cans, so didn't try either use option.

I don't recall strong opinions either way. For safety and handling, getting rid of the extra gas on the roof, tailgate or interior of the car, as soon as possible is a good idea. But leaving those cans for later, or even just emergency use, has some psychological advantages. It is nice to have some gas 'set aside' for emergency use. By the time you have to use that gas, you'll be focused on getting back to civilization.

In a sense the drop tanks worked for the WW2 planes because they were on a planned flight, one that was intentionally pushing the limits of the built in fuel capacity. They weren't carrying the extra tanks for emergency use, for use just in case the flight took longer than expected.

 

[R_Lefebvre]

The drop tanks in WWII were not just for emergency use. They were instrumental in many of the missions that were well outside of the normal range of the planes. I also don't see how there would be any more risk in them being shot at. It's not like the regular fuel tanks in the wing or fuselage were any more secure. And in WWII, you don't choose which part of the airplane you're going to hit anyway. You pull the trigger and hope you hit something.

Anyway, for the trucks, that's a good question. I prefer to use the tanks as you say, empty them into the main tank as soon as possible. However, it does leave you with no way to transfer fuel to another group member who needs it. Most/all? modern vehicles have anti-siphon screen in the filler neck. I've tried it on a fuel vehicles with zero success.

 

[cruiseroutfit]

I often do that with my fuel cans, it rare that I'll being full ones home, instead I'll use up any cans I have. However your method seems like a bunch of added work and headache when a $20-80 fuel can could cleanly be stowed without worry of leak in the back of your truck. Your already allotting the space to a fuel container, why not get a reliable one that your not worried about leaking that you can just have?

 

[off-roader]

FWIW, I have 2 blitz cans that I no longer use simply because they easily leak fuel. I would imagine plastic cans would too (hence the reason you put them in plastic bags right?).

I use strictly nato cans these days because they are leak proof even if they are illegal to use in CA (stupid law BTW).

As for the siphon problem you mentioned, they do make siphons (under $10) that you don't have to prime w/ your mouth.:ylsmoke:

 

[MoGas]

I do it similarly. I carry up to 25 extra gallons in Wedco cans, usually on the roof. I like to drop the high weight as soon as I can, so if I am ~1/2 tank, and at a convenient area, I'll put some fuel into the main tank.

Dave

 

[HarryT]

When I saw "drop tanks", I though you were going to leave the tank on the trail.
I've stashed fuel so it could be used for the return trip when riding a dual sport
motorcycle and have towed a trailer with two barrels of fuel behind my Jeep.
You can't have too much fuel or water.

 

[michaelgroves]

The gas can discussion below prompted me to think about how I use my spare gas can. Thought I'd see if anyone else does what I do.

When I was a kid, like many kids I started getting interested in things related to airplanes, especially WWII fighter planes. I noticed right away that often times they'd have teardrop shaped pods under the wings. When I read a little more I found out these were extra fuel tanks.

Now at first I thought "that's the stupidest thing in the world! If they get into a fight with an enemy aircraft, the first thing the enemy is going to do is try to shoot at their fuel tanks!"

But of course, I was the one who was stupid (really just ignorant) because I didn't realize how they used those fuel tanks: They were "drop tanks" and the idea was that they'd take off from their (presumably secure) base in England or France or Guadalcanal or New Guinea or wherever, and they'd use the fuel from the drop tanks. Then, either when the fuel in the drop tanks ran out, or when they sighted enemy planes, they'd pull a lever and drop the tanks and at that point they'd use the "internal" fuel tanks built into the plane.

When I went to the Maze District last year my original plan had me spending at least 2 days away from any sources of fuel. With only 18.5 gallons, I was a bit worried about my Tacoma being able to go the distance.

On the other hand, I didn't have any external mounting points for fuel cans, and for that matter I didn't own any fuel cans at all other than one of those 5 gallon plastic "blitz" cans. I know those aren't the most rugged cans and since my cargo compartment is also my sleeping compartment, the last thing I wanted was to have gas sloshing around there.

So, I figured I'd use my plastic can as a kind of "drop tank." What I did was this: When I filled up with gas in Green River (last gas stop for a couple of days), I filled both my tank and the can. Figuring that I typically get around 18-21 MPG, my estimate was that 5 gallons would get me ~110 miles.

So, I carefully placed the full gas can (inside a heavy plastic bag) in the back of the truck and drove off. I watched the trip odometer and that night, when I made camp, I noted that I had put around 120 miles onto the truck since filling up. At that point, I emptied the 5 gallon can into the tank, figuring that it was safer, cleaner, and just generally easier to carry my "extra" fuel that way rather than have it sitting in the can. After I emptied the can, I opened it up to let it vent and let it sit out all night. Next morning I capped it, wrapped it up in the plastic bag and taped the bag securely shut (from that point on I knew I would be hitting a gas station at least once a day.)

There are a lot of good reasons for carrying extra gas in a can (for one thing, that makes it easy to offer to a buddy or stranded traveler without risking the mouthful of gas you could get using a siphon hose) but for me, using the "drop tank" method was easier and more convenient. I still got the benefit of the extra gas - in effect, it gave me a 23 gallon tank - but I didn't have to worry about a full fuel can bouncing around in the back of the truck, nor did I have to worry about leaks, fumes, etc.

Just wondering if I'm the only one who uses my spare gas cans this way? Does everyone else just leave them full until/unless they're needed?

Wow.. that's a long way of asking, "Do you use your spare fuel first?" :elkgrin:

The answer's generally yes, in my case. But if there are several legs of the journey that might (but probably won't) require the use of the spare fuel, then I'd leave it in the cans.

But long-range tanks - that's what you want for extra fuel...

 

[kellymoe]

Drop tanks also make for some pretty bithcin salt flat racers too. They go for a premium these days in the speed world.

 

[Martinjmpr]

But long-range tanks - that's what you want for extra fuel...

In a perfect world, I'd agree but the problem is that I don't know of any long range tank (at least for my vehicle) that goes for less than $1000 by the time you get it installed.

At that point you have to start doing some serious cost/benefit analysis. For me the 1 time a year that a bigger tank might come in handy is not worth the expense.

It's too bad most vehicles for the American market have <20 gallon tanks. My Montero had a 24.5 gallon tank, but then again it was made in Japan for a world market. Montero/Pajero is used in many parts of the world where gas stations aren't nearly so close together as they are in the US.

The Prado we had in Kuwait had an auxiliary tank, too. I'm not certain, but I think that the Lexus GX470 (the version of the Prado in the US market) has the spare tire where the extra gas tank was in our world-spec Prado (World-spec Prados have side-hinged rear doors with the spare on the tailgate. Lexus GX470's have a 1 piece liftgate with the spare tire under the body behind the rear axle.)

With the extra tank (something like 200l total) That Prado had a range in excess of 1200 km (720 miles) at least according to the onboard computer. :Wow1:

 

[Pskhaat]

Just FYI on the LCs and Prados, the aux. tank was above the spare tire (if you can believe that, at least on the LCs).

 

[BlueBomber]

I see alot of people on here cutting the door panels and other plastic suff out to reach "cubbies" in their vehicles. How hard would it be to place two small aux. tanks in these little cubbies? Jazzmakes some 1,2 and 3 gallon fuel cells that look pretty small. they even make 1 and 2 quart cells for JR. dragsters.

Edit: I think the Bomber needs drop tanks...I was already going to mock up some bombs ( for mall cruzing) and some torpedos ( scare the boaters at the lake). I think drop tanks would be awesome.

 

[Antichrist]

The drop tanks in WWII were not just for emergency use. They were instrumental in many of the missions that were well outside of the normal range of the planes. I also don't see how there would be any more risk in them being shot at. It's not like the regular fuel tanks in the wing or fuselage were any more secure.

<HIJACK>
By the time drop tanks came in to use, later in the war, most allied fighters had self-sealing tanks. I don't think the drop tanks were self-sealing. But, the main reason they dropped them when going in to combat was that they were a severe hindrance on performance. Since some of the planes were so evenly matched the pilots didn't want anything hindering them. Some even regularly waxed their planes to get a few more mph out of them in combat.
</HIJACK>

 

[R_Lefebvre]

Self sealing yes, but if shot badly enough, they'd still catch fire. But yes, mostly a performance thing. Interestingly, the first operational US jet plane, the P-80 Shooting Star had the first wing tip mounted fuel tanks, which were discovered to actually increase performance. That is why most images you see of the plane include the tanks, because they just didn't bother jetisoning them anymore.