Simviation Forum - Switching Tanks

Jan 24^th, 2010 at 12:19pm

ShaneG Offline
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While flying a plane with only left & right tanks, how often should you switch between the two, to keep the fuel load balanced, and keep the plane from pulling to one way or the other?

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Reply #1 - Jan 24^th, 2010 at 12:45pm

specter177 Offline
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It all depends. We do it every half-hour, but you could probably do it every hour if you wanted.

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Reply #2 - Jan 24^th, 2010 at 4:17pm

Brett_Henderson Offline
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My method, in a Warrior Wink

... is to takeoff and climb on the fullest tank.. switch at altitude.. and then switch every 20 minutes..

It's situational though.. How much fuel you start with.. how much the tanks might already be out of balance.. and how long you plan on flying.

On a LOOONG flight where you start with full tanks.. 30 minutes per switch is more practical.. An hour is pushing it though.. not only becuase you can get as much as 50 lbs out of balance, but you can also end up pushing one tank too near empty.

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Reply #3 - Jan 24^th, 2010 at 4:22pm

ShaneG Offline
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Brett_Henderson wrote on Jan 24^th, 2010 at 4:17pm:

My method, in a Warrior Wink

... is to takeoff and climb on the fullest tank.. switch at altitude.. and then switch every 20 minutes..

It's situational though.. How much fuel you start with.. how much the tanks might already be out of balance.. and how long you plan on flying.

On a LOOONG flight where you start with full tanks.. 30 minutes per switch is more practical.. An hour is pushing it though.. not only becuase you can get as much as 50 lbs out of balance, but you can also end up pushing one tank too near empty.

Oddly enough, that's the exact plane I'm asking this question for. Wink

I try to only load enough fuel for each flight, avoiding a full tank weight penalty for short flights, and noticed once that the plane kept pulling to the left before I figured out it was the fuel imbalance. Roll Eyes

I then remembered the same thing in the real deal, and how you switched tanks, and it's the same on the FS model, just wasn't sure what an optimal rate would be.

Thanks for the help.

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Reply #4 - Jan 24^th, 2010 at 4:32pm

olderndirt Offline
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Depends on tank capacity and fuel burn. A cub, for instance, holds eighteen a side and burns about 8-9 an hour so that would be about 50-55 lbs. Personally, I took off on the left then switched after level-off. If the flight was planned for more than two hours, I'd run it dry - otherwise, if trim is a problem, switch but plan to be on the fullest for landings and takeoffs. In my case, always the left.

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Reply #5 - Jan 24^th, 2010 at 11:24pm

C170b Offline
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In our Cessna T210L, we did 20 minutes a tank.

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Reply #6 - Apr 16^th, 2010 at 4:43pm

Tyler012 Offline
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Does FSX take care of switching the tanks automatically? Or is there an option in light aircraft to draw from both tanks at once?

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Reply #7 - Jun 29^th, 2010 at 6:17pm

Andy Hughes Offline
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I've been flying for a while (since '94) and don't see the need to switch tanks that often.
In a Mooney (pre-J), cruise is about 9GPH and climb is 12-15 GPH.
Climb at 1000 fpm for 10 minutes - 10K, 500 fpm for 20 minutes - 10K.
Basically I guestimate how long I have to fly before I use up the first 4 or 5 gallons.
It's going to be 20 minutes if I climb to 10K at 500fpm. OR it's about 15 minutes after reaching 8000 if I climbed at 1000 fpm.
Then I switch every hour, so I'm out of balance by no more than 4 or 5 gallons at any one time (24-30 pounds).
I have never noticed much of a tendency to "lean" to one side.
In a comanche, I climb on the main, then switch to the oposite aux tank (outboard, 15 gals), empty it, then empty the other aux, then
switch to the "other main", then switch every hour. Again, no real tendency to lean.
In arrows, again, 1st half hour on one tank, then switch every hour.

FS does not switch the tanks for you automatically, however if you do not set it to one tank or the other, it will draw from both equally.

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