Originally Posted by riobison
Why not just function the selector, turn it to the fullest tank and leave it there until safely in the air at altitude and then start changing tanks as needed? Thanks Tim
Tim you are thinking correctly. The one basic rule of thumb is have boost pump on and selector to tank with fuel. Period. Switch as you like otherwise. I am NOT a fan of switching tank back and forth right before take-off. I switch to keep tanks fairly balanced on ground or air... and select the proper tank. As long as there is no big difference in fuel level or imbalance either tank, either tank is proper. I don't adhere to absolute fullest tank.
One way to minimize switching:
1) Select "proper tank", typically fullest.
2) start, taxi and run up, do not switch tank
3) boost pump on, take off
4) Airborne (with sufficient altitude) turn boost pump off.
5) As required or desired to keep balance turn boost on and select opposite tank, boost pump off.
I searched the internet for Piper checklist. Piper being low wing is closest thing to the RV. I saw a wide variation.
One says start on fullest. Then before takeoff "select proper tank
". I saw "PROPER tank" not fullest several times.
What does that mean? If the tank difference is small use either tank. This is my technique.
Example L tank 65% and R tank 55% entering pattern on R tank. Switching from R tank you were are on last 30 minutes to L tank make sense for 10%?
Now if you screwed up en-route, R tank was 10% and L tank 50% by all means switch to L tank. I would do that on initial descent not pattern.
Unrelated but the Ted Smith Aerostar (Later Piper Aerostar twin engine, mid wing) I flew had wing and aux tanks. It was complicated. Fuel balance and not running the Aux tank dry before wing tanks was critical. The wings were skinny and you could un-port fuel pickup if too low in double cross feed (bypass Aux tank). If you ran the Aux dry before the wing tank you could also starve the engine. There were a few accidents due to fuel mismanagement. RV' have one engine, one selector, one pump and two tanks. Not that hard.