Managing fuel burn on x-country w/C172
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Managing fuel burn on x-country w/C172
guys,
I just had a question about how most of you manage your fuel on a x-country flight with a C172. Do you normally leave the fuel valve on both or do you switch it over to left/right after take off, then once you're down to a few gallons on one side you switch over to the other? I normally leave it on both, but I'd like to hear what some of you out there are doing. I've heard on some airplanes, you have to switch tanks after so many hours etc. What is your best practice on fuel management for a C172?
Thanks
SVENSK!
I just had a question about how most of you manage your fuel on a x-country flight with a C172. Do you normally leave the fuel valve on both or do you switch it over to left/right after take off, then once you're down to a few gallons on one side you switch over to the other? I normally leave it on both, but I'd like to hear what some of you out there are doing. I've heard on some airplanes, you have to switch tanks after so many hours etc. What is your best practice on fuel management for a C172?
Thanks
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Not sure I like the idea of letting one tank run nearly dry. The gauges are unreliable at the best of times! (why would you run the risk of a fuel stoppage??) Not to mention the longitudinal trim issues that would arise.
Why not just select the appropriate tank (or both) to maintain a balanced loading?
Not flown the 172 myself, but I have flown other aircraft with selectable tanks. Its good practise to switch from one tank to another during run ups to ensure you have a positive feed from each tank.
Speak to your instructor if I were you
Why not just select the appropriate tank (or both) to maintain a balanced loading?
Not flown the 172 myself, but I have flown other aircraft with selectable tanks. Its good practise to switch from one tank to another during run ups to ensure you have a positive feed from each tank.
Speak to your instructor if I were you
Last edited by Slipstream86; 17th Mar 2010 at 00:04.
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Isn't the C172 gravity feed? Just leave it on both unless you have a fuel imbalance for some reason (fuel addded to one side only - or previous operator ran down one tank?).
Your question may be more appropriate for low wing (such as pipers) where you cannot run off both tanks - an engine driven pump delivers the fuel from the selected tank. For pipers I usually just run 30 minutes on each side assuming I am starting off with equal fuel in each tank. If one tank has more fuel then run that down until equal or less than the other.
Your question may be more appropriate for low wing (such as pipers) where you cannot run off both tanks - an engine driven pump delivers the fuel from the selected tank. For pipers I usually just run 30 minutes on each side assuming I am starting off with equal fuel in each tank. If one tank has more fuel then run that down until equal or less than the other.
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I have flown the C172. The C172 is gravity fed, so no need for fuel pump on takeoff. I seem to recall fuel is selected to both to ensure a balanced burn and in terms of fuel management; I would advise you LEAN the mixture, unless you want to burn 10 US GAL/hr instead of 6 US GAL/hr. You want to ensure the mixture knob is on the "rich" side, by increasing the richness by 2 turns clockwise (at least in the a/c I've flown).
As stated above, check with your instructor, as every a/c is slightly different.
As stated above, check with your instructor, as every a/c is slightly different.
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C172 is gravity feed, and I actually run it on both all of the time. I simply wanted to know what other C-172 drivers do on their x-country flights, that's all. I have heard that on pipers you do have to switch tanks after a few minutes though.
SVENSK!
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SVENSK
Start with your POH as it has all the answers , the norm is both but there are some exceptions such as fuel inbalance etc. its been a while since I flew one in traning bit its all in the manual.
Start with your POH as it has all the answers , the norm is both but there are some exceptions such as fuel inbalance etc. its been a while since I flew one in traning bit its all in the manual.
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Yes, I was taught to switch tanks in the Pa38/28 I use to fly, but since flying the C172, the fuel has been kept on both. You have manual control there if you want it any how, by selecting L or R.
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I flew the C172 from Orlando to Alabama (near Birmingham) on one tank of fuel, it took about 5 hours.
Keep the tank fuel selector on both, but if you have a cross wind then one tank will burn quicker than the other so watch out for that. If that is the case then simply switch the valve left or right till its balanced.
If you have an EGT/GPH gauge- lean the mixture till both the needles are touching eachother (horizontally) as this is the optimum so I have been told.
If the EGT gauge is broken then simply lean the mixture slowly till the engine starts to sound like its going to lose power then move the mixture control slight forward of that. That is also Piper's SOP's on how to lean the engines on there aircraft. My instructor contacted them to find out.
Keep the tank fuel selector on both, but if you have a cross wind then one tank will burn quicker than the other so watch out for that. If that is the case then simply switch the valve left or right till its balanced.
If you have an EGT/GPH gauge- lean the mixture till both the needles are touching eachother (horizontally) as this is the optimum so I have been told.
If the EGT gauge is broken then simply lean the mixture slowly till the engine starts to sound like its going to lose power then move the mixture control slight forward of that. That is also Piper's SOP's on how to lean the engines on there aircraft. My instructor contacted them to find out.
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Pipers behave differently as there is no 'both' setting, thus you have to switch regularly.
Cessnas will often/usually empty the tanks unevenly due to the way the venting and crossfeeds work - personally it's not something I worry about, they even out in the end, the engine won't quit until both are empty. Crosswind has nothing to do with it however.
'Both' should be selected as per the POH for takeoff and landing, as out of balance flight can uncover one or other tank feeds.
Leaning is an entirely separate subject I won't get into here, just do it by the POH.
Cessnas will often/usually empty the tanks unevenly due to the way the venting and crossfeeds work - personally it's not something I worry about, they even out in the end, the engine won't quit until both are empty. Crosswind has nothing to do with it however.
'Both' should be selected as per the POH for takeoff and landing, as out of balance flight can uncover one or other tank feeds.
Leaning is an entirely separate subject I won't get into here, just do it by the POH.
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if you have a cross wind then one tank will burn quicker than the other so watch out for that
If you have an EGT/GPH gauge- lean the mixture till both the needles are touching eachother (horizontally) as this is the optimum so I have been told.
If the EGT gauge is broken then simply lean the mixture slowly till the engine starts to sound like its going to lose power then move the mixture control slight forward of that. That is also Piper's SOP's on how to lean the engines on there aircraft. My instructor contacted them to find out.
If the EGT gauge is broken then simply lean the mixture slowly till the engine starts to sound like its going to lose power then move the mixture control slight forward of that. That is also Piper's SOP's on how to lean the engines on there aircraft. My instructor contacted them to find out.
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BackPacker,
Regarding the wing low technique during the cruise, I didnt mean that at all. During my cross country flying I found that when having a cross wind one tank burned more quickly than the other.
An examiner and numerous instructors mentioned the EGT/GPH gauge to lean the engine.
Also about using the same techniques for different planes: Of course I wouldn't suggest doing that all I did was merely mention that the same technique just so happend to be used on pipers as well.
If in doubt check the POH
Regarding the wing low technique during the cruise, I didnt mean that at all. During my cross country flying I found that when having a cross wind one tank burned more quickly than the other.
An examiner and numerous instructors mentioned the EGT/GPH gauge to lean the engine.
Also about using the same techniques for different planes: Of course I wouldn't suggest doing that all I did was merely mention that the same technique just so happend to be used on pipers as well.
If in doubt check the POH
When leaning, keep an eye on the oil temp gauge. If it goes up, you might want to enrich it a tad more.
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During my cross country flying I found that when having a cross wind one tank burned more quickly than the other.
An examiner and numerous instructors mentioned the EGT/GPH gauge to lean the engine.
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I said that the needles would be horizontal from each other not just intercepting each other.
Well if im flying wings level, ball in the centre, with wind correction and it still does it im guessing it must be that aircraft in particular. Alot of the students used to sit on the elevators to lift the nose wheel up so they can maneuver the aircraft on the ground, this would cause the plane to have natural turning characteristics due to damage and strain.
If I managed to get 5 hours straight out of a 172 I must of done something right
Well if im flying wings level, ball in the centre, with wind correction and it still does it im guessing it must be that aircraft in particular. Alot of the students used to sit on the elevators to lift the nose wheel up so they can maneuver the aircraft on the ground, this would cause the plane to have natural turning characteristics due to damage and strain.
If I managed to get 5 hours straight out of a 172 I must of done something right
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As I noted, the 172 will generally burn fuel unevenly out of both tanks; this is because there is a vent in one side, and an internal crossfeed to vent the other.
It has nothing to do with crosswind, the aircraft flies in an air mass, and has no concept of how that air mass is moving.
As for the other, I'm pretty sure EGT should be fairly constant for a properly leaned engine at a given throttle setting. As you climb (and re-lean), the fuel flow will reduce.
It has nothing to do with crosswind, the aircraft flies in an air mass, and has no concept of how that air mass is moving.
As for the other, I'm pretty sure EGT should be fairly constant for a properly leaned engine at a given throttle setting. As you climb (and re-lean), the fuel flow will reduce.
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172 leave on 'both'. There is a slight imbalance as to which tank empties first, due to the venting installation. This can get quite pronounced on the 182 (don't ask me why), and those I sometimes fly in such a way that fuel is first drawn from the slower-emptying tank. After an hour or so, back to 'both'.
The PA28 series of course doesn't have a 'both' selector, so you have to switch tanks. My way of doing so is to fly on the tank corresponding to the position of the minute hand on my wristwatch. IOW, if in the left hemisphere, left tank, right hemisphere, right tank. Keeps it balanced.
The PA28 series of course doesn't have a 'both' selector, so you have to switch tanks. My way of doing so is to fly on the tank corresponding to the position of the minute hand on my wristwatch. IOW, if in the left hemisphere, left tank, right hemisphere, right tank. Keeps it balanced.
If flying a rental plane, on a long trip I run one tank very low, checking it at stops. Then I have an indication of fuel burn. On final leg, I'm happier with one half full tank, then two tanks both quarter full. Pa28 and Pa38 feel O.K with tank imballance.
