Switching fuel tanks in route?
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Switching fuel tanks in route?
When I had my C140 25 years ago, I used to burn from one tank on cross countrys and switch every hour. I remember burning one tank dry so as to have more fuel in the other tank for landing. How does the membership burn fuel from tanks on long x countrys? Thanks, GARY new guy.
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Dave Clark
- Posts: 894
- Joined: Mon Apr 22, 2002 6:25 pm
I know I'll get flamed on this but here goes...
If I'm planning a long leg and really want to monitor the fuel closely the only way I know how long I can stay up (and the watch is my fuel gauge) I will take off on both then either at my cruising altitude, or at a safe altitude during a long climb, I will swithch to the right tank. I'll burn it for one hour then switch to the left for one hour then back to the right until it runs dry (the exciting moment). The time it takes to run dry after you switch back to the right tank is the time you will have on the left tank when you switch back to it. This is assuming you have not changed the power settings. I make sure I'm down 45 minutes less than that. It's a little more complicated due to my Javelin tank but you get the idea.
Be aware that theoretically you should be on both tanks to land due to possible loss of fuel at the tank pickup in a turn or slip so I'm very careful about that.
I don't use the proceedure most of the time, just when I want to know on a long leg. Due to the Javelin many times I have little use of the left tank on cross countries because I need to burn off the right tank first so that I can pump the Javelin into it.
If I'm planning a long leg and really want to monitor the fuel closely the only way I know how long I can stay up (and the watch is my fuel gauge) I will take off on both then either at my cruising altitude, or at a safe altitude during a long climb, I will swithch to the right tank. I'll burn it for one hour then switch to the left for one hour then back to the right until it runs dry (the exciting moment). The time it takes to run dry after you switch back to the right tank is the time you will have on the left tank when you switch back to it. This is assuming you have not changed the power settings. I make sure I'm down 45 minutes less than that. It's a little more complicated due to my Javelin tank but you get the idea.
Be aware that theoretically you should be on both tanks to land due to possible loss of fuel at the tank pickup in a turn or slip so I'm very careful about that.
I don't use the proceedure most of the time, just when I want to know on a long leg. Due to the Javelin many times I have little use of the left tank on cross countries because I need to burn off the right tank first so that I can pump the Javelin into it.
Dave
N92CP ("Clark's Plane")
1953 C-180
N92CP ("Clark's Plane")
1953 C-180
I've got a ragwing with the interconnected tanks on the right side.
I fly around with the fuel selector on right until the gauge reads 1/2. (My gauges have demonstrated themselves to be realtively accurate compared to fuel burn per tach time.) At this point I put the selector on both until it's time to stop for fuel. At shutdown I leave the selector on right again for refueling...whether or not it really makes a difference I don't know, but it doesn't hurt I guess.
Flying off the right tanks also helps with lateral balance of the airplane... i.e. it gets rid of the heavy right wing since topped off that side holds twice the fuel that is in the left wing.
I do this for every flight, either local or cross county.
I fly around with the fuel selector on right until the gauge reads 1/2. (My gauges have demonstrated themselves to be realtively accurate compared to fuel burn per tach time.) At this point I put the selector on both until it's time to stop for fuel. At shutdown I leave the selector on right again for refueling...whether or not it really makes a difference I don't know, but it doesn't hurt I guess.
Flying off the right tanks also helps with lateral balance of the airplane... i.e. it gets rid of the heavy right wing since topped off that side holds twice the fuel that is in the left wing.
I do this for every flight, either local or cross county.
1948 C170 N4281V
Switching Fuel Tanks
Overall I agree with George. Put em on both and forget em. However, like some others, if I am on a long trip, especially if I think I will be 3 1/2 hrs or more, I do run on the right tank (because I can see that gauge much easier) until it is darn near empty (needle completely stops moving) or until it runs dry. I then know I have almost that same amount of time left due to the left tank being almost full. Even if I take off with both tanks absolutely full & do so on the right tank, before I have emptied 1/2 or 3/4 of the right tank the left tank gauge needle is starting to dance around. Obviously some fuel from the left tank must be cross feeding to the right tank? In my 172 TD the most I can get into the left tank when it is absolutely bone dry (sump drain pulled out--don't know if any is trapped by any baffels or not) and on what appears to be level ground/ramp, is 19.6 gallons. I have flown slightly over 4 hours on one or two times, but believe me the pucker power was at the maximum going into Farmington, NM & then had to go out North of the airport to let some guy in that had an emergency---thought I might myself! I used to fly even on short trips on right tank until it ran out, then switch. Fortunately I never encountered any problem with switching and the engine picking right back up. However I stopped doing that when I was flying over Possum Kingdom Lake one day and forgot to switch to either both or left tank and it ran out with me in a slight banking turn to the right and me about 100 feet off the surface. Taught me another lesson.
Ole Pokey
Ole Pokey
For the most part I stay on both. For the times that I switch to one tank, I have a message reminder on my GPS. Once every hour, that my GPS is on, I get a flashing light to check messages. Message reads, Fuel on Both Tanks? This is a nice reminder to check fuel management even when flying on both. Also acts as a timer. That message function is handy for several reminders, ex "change oil".
Last edited by AR Dave on Sat Oct 25, 2003 3:15 am, edited 1 time in total.
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Mike Smith
- Posts: 175
- Joined: Mon Jun 02, 2003 2:53 pm
I have a '50 170A and I takeoff on both and then enroute (short or long flights) switch left to right (and vice versa) to maintain a balanced fuel condition about every 15 minutes. Most times I don't have to go to the left, I just switch from right to both since the left seems to feed quicker than the right. I figure this helps keep me aware of my fuel state and it just seems "right" to be within 1/4 tank of balanced. All the techniques on this forum seem to be safe though. Oh yes, I also always land in "both". By doing this, when I refuel I'm always within a gallon or two of the same burn on each side which tells me the fuel guages are reading the correct relative amounts.
Mike Smith
1950 C-170A
1950 C-170A
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rudymantel
- Posts: 451
- Joined: Sat Nov 23, 2002 4:03 pm
I had ocasion to scare the heck out of myself a few years ago. Four or five years ago I bought a C-175 in El Monte, CA. It had been sitting so long in it's tracks (for several years) that it still had 80 octane aviation gasoline in both tanks. I drained the tanks, flushed the fuel system and prepared the plane for the trip from CA to Payson, AZ. That trip was a "super pucker" because of wondering what the engine had in store for us after such a lengthy hibernation. No problems arose at all on a beautiful flight over the Mojave Desert and western AZ. We flew around Arizona for a couple of months then, one fresh cool morning, I set out for Louisiana.
That morning I took my grand-son for a early morning flight that lasted a little over a holf hour(estimated). After returning to Payson airport and bidding him goodby I set out toward the East. As my usual procedure is when flying over hostile terrain I went 'high'. I climbed to 10.5 and GPSed my way around the MOAs and Restricted areas near El Paso. I had debated with myself on the number of fuel stops I would make but didn't want to have to land at our home strip very long after sunset. I figured with the 56gal onboard I could easily make the 1100mi on one stop so a 550 mile legwould put me in at Midland/Odessa. I had no com radio so I planned to land at 7T7.
Somewhere east of El Paso I noticed that the fuel gage for the right tank showed considerably more fuel than the left. At that time I decided to switch to the right to "balance" the trim of the plane. It wasn't really out of trim but I switched any way and after about ten minutes, imagine my shock, the engine quit! I very quickly did two things (after peeing my pants). I switched back to "Both" and punched in "Nearest" on the GPS! The engine picked back up and my heart slowed back to emergency mode. Winkler County came up 16 miles South and I made a bee-line for it. I had about 6000' agl and figured if I could make 10 miles at my cruise altitude I could glide the rest of the way. Long story shorter. I made the airport just fine and found out several things upon refueling. Both fuel gages were in error. the left tank showed "zero" but had 13 gallons of fuel! The left tank showed 3/4 full and had fumes!
Lessons learned - -
1. KNOW YOUR FUEL BURN!
2. NEVER BELIEVE A FUEL GAGE ON AN UNFAMILIAR AIRPLANE!
3. AND DON'T STRETCH THE LIMIT!
There were several times when I could have calculated a reasonable estimate of what this particular bird was gulping but didn't think it important at the time. The realization, at Winkler County Airport, that the burn was in excess of 14GPH startled me to say the least! A less than careful estimate of the flight time I used beforfe I left Payson for points east may have exacerbated the situation.
I have flown lots of planes to "minimum needed remaining" at my destination but that is the last time I will trust to "luck" when it comes to putting the "stuff" in the tank and knowing pretty close how far I will go before re-fueling! My FWIW
P.S. The "OLD" fuel selector valves on our 170s have been known to fail. Probably best to leave them on both while in the air!
That morning I took my grand-son for a early morning flight that lasted a little over a holf hour(estimated). After returning to Payson airport and bidding him goodby I set out toward the East. As my usual procedure is when flying over hostile terrain I went 'high'. I climbed to 10.5 and GPSed my way around the MOAs and Restricted areas near El Paso. I had debated with myself on the number of fuel stops I would make but didn't want to have to land at our home strip very long after sunset. I figured with the 56gal onboard I could easily make the 1100mi on one stop so a 550 mile legwould put me in at Midland/Odessa. I had no com radio so I planned to land at 7T7.
Somewhere east of El Paso I noticed that the fuel gage for the right tank showed considerably more fuel than the left. At that time I decided to switch to the right to "balance" the trim of the plane. It wasn't really out of trim but I switched any way and after about ten minutes, imagine my shock, the engine quit! I very quickly did two things (after peeing my pants). I switched back to "Both" and punched in "Nearest" on the GPS! The engine picked back up and my heart slowed back to emergency mode. Winkler County came up 16 miles South and I made a bee-line for it. I had about 6000' agl and figured if I could make 10 miles at my cruise altitude I could glide the rest of the way. Long story shorter. I made the airport just fine and found out several things upon refueling. Both fuel gages were in error. the left tank showed "zero" but had 13 gallons of fuel! The left tank showed 3/4 full and had fumes!
Lessons learned - -
1. KNOW YOUR FUEL BURN!
2. NEVER BELIEVE A FUEL GAGE ON AN UNFAMILIAR AIRPLANE!
3. AND DON'T STRETCH THE LIMIT!
There were several times when I could have calculated a reasonable estimate of what this particular bird was gulping but didn't think it important at the time. The realization, at Winkler County Airport, that the burn was in excess of 14GPH startled me to say the least! A less than careful estimate of the flight time I used beforfe I left Payson for points east may have exacerbated the situation.
I have flown lots of planes to "minimum needed remaining" at my destination but that is the last time I will trust to "luck" when it comes to putting the "stuff" in the tank and knowing pretty close how far I will go before re-fueling! My FWIW
P.S. The "OLD" fuel selector valves on our 170s have been known to fail. Probably best to leave them on both while in the air!
OLE GAR SEZ - 4 Boats, 4 Planes, 4 houses. I've got to quit collecting!
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rudymantel
- Posts: 451
- Joined: Sat Nov 23, 2002 4:03 pm
Rudy - I have a discontinued Garmin 150 (located at the bottom of this webpage). The 150XL replaced mine. I figure they all have the message function and a whole lot of other abilities, like the fuel flow management, that I don’t know how to use.
http://www.garmin.com/aviation/products ... anel-mount
I recently decided that I would start strapping my tanks, instead of just looking in to see if they are wet. I keep up with how much time I’ve flown since fueling, ½ hr yesterday, 1 hr this morning, ½ hr to this place, and watch the fuel gauges. But I think nothing could be more accurate than knowing exactly how many gallons are in each tank by using a dipstick. I was going to ask about using a clear tube, to measure fuel on preflight, but see they allready sale such a product. Any Tips? Is this a commonly used method?
Under search, I found “Gas Gauge Calibration”. I decided not to give my 2 cents on the subject as to keep the past discussion buried. OK, just a LIL bit. Without going into a lot of detail, I depended on a gauging stick for a few landing ruts in AK. I dumped gas, (in to can) down to my 45 min mark, every time I bounced off my base camp's, dry creek bed. 2723D had a Very Valid Question and knowing exactly how many pounds are in those tanks can be very crucial, in country where wheel pants aren’t the rage.
http://www.garmin.com/aviation/products ... anel-mount
I recently decided that I would start strapping my tanks, instead of just looking in to see if they are wet. I keep up with how much time I’ve flown since fueling, ½ hr yesterday, 1 hr this morning, ½ hr to this place, and watch the fuel gauges. But I think nothing could be more accurate than knowing exactly how many gallons are in each tank by using a dipstick. I was going to ask about using a clear tube, to measure fuel on preflight, but see they allready sale such a product. Any Tips? Is this a commonly used method?
Under search, I found “Gas Gauge Calibration”. I decided not to give my 2 cents on the subject as to keep the past discussion buried. OK, just a LIL bit. Without going into a lot of detail, I depended on a gauging stick for a few landing ruts in AK. I dumped gas, (in to can) down to my 45 min mark, every time I bounced off my base camp's, dry creek bed. 2723D had a Very Valid Question and knowing exactly how many pounds are in those tanks can be very crucial, in country where wheel pants aren’t the rage.
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Dave Clark
- Posts: 894
- Joined: Mon Apr 22, 2002 6:25 pm
Yeah, and every morning ever since when you look in the mirror!flyguy wrote:I had ocasion to scare the heck out of myself a few years ago.
The 175 only has 52 gallons. (of which only 42 are useable). Perhaps old age is creeepin' up on you?flyguy wrote: I figured with the 56gal onboard I could easily make the 1100mi on one stop so a 550 mile legwould put me in at Midland/Odessa.
You must be getting younger according to George, Flyguy!gahorn wrote:Yeah, and every morning ever since when you look in the mirror!flyguy wrote:I had ocasion to scare the heck out of myself a few years ago.
The 175 only has 52 gallons. (of which only 42 are useable). Perhaps old age is creeepin' up on you?flyguy wrote: I figured with the 56gal onboard I could easily make the 1100mi on one stop so a 550 mile legwould put me in at Midland/Odessa.
George speedtalk:
Full Speed Ahead = damn slow to the rest of us!
Stopped = going backwards a little to the rest of us!
Creepin = there aint no telling how much in reverse that is!
And, it might not just be the speed issue that George always lands in the dark. All of us look a little better under those conditions.
Joe
51 C170A
Grand Prairie, TX
51 C170A
Grand Prairie, TX
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Paint mixing sticks,available at your local paint store,are handy for dipping tanks. I have 2,one for the hangar & one (trimmed a little shorter) carried in the seatback pocket in the airplane. I emptied a tank & refilled 5 gallons at a time,marking my sticks as I went,so I can dip the tanks & tell within a gallon or so just how much fuel I have on board. I keep track of ALL my fuel purchases,so I know that my 170 has averaged almost exactly 8.0 gallons per tach hour over the 6 years I've owned it. It's burning more during climb & less during descent,of course,but overall it's 8.0 gph. Makes for easy fuel burn calculations.
Eric
Eric