Van's Air Force
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RV-12 Boost Pump
- Thread starter n233va
- Start date
It was a design choice that has a number of benefits, and virtually no negatives.
A couple of major reasons...
The RV-12 was designed to meet the LSA requirements, to be flown by a Sport Pilot. By design that means a simple to fly and operate airplane.
Having the pump always operating removes one item that a pilot can potentially forget. Numerous RV-12's have already been crashed because pilots forgot to latch the canopy before take-off... and then forgot to fly the airplane instead of concentrating on the canopy....
The optimal fuel for the Rotax engine is premium auto fuel. It typically has a higher vapor pressure than avgas which makes it more susceptible to vapor lock. A boost pump near the fuel tank, pushing cool (compared to the engine compartment) fuel to the engine, vs just an engine drive pump sucking fuel the entire length of the fuel system, can help to greatly reduce the possibility of vapor lock. This is the same reason most cars for many years have had a fuel pump located in the fuel tank.
A couple of major reasons...
The RV-12 was designed to meet the LSA requirements, to be flown by a Sport Pilot. By design that means a simple to fly and operate airplane.
Having the pump always operating removes one item that a pilot can potentially forget. Numerous RV-12's have already been crashed because pilots forgot to latch the canopy before take-off... and then forgot to fly the airplane instead of concentrating on the canopy....
The optimal fuel for the Rotax engine is premium auto fuel. It typically has a higher vapor pressure than avgas which makes it more susceptible to vapor lock. A boost pump near the fuel tank, pushing cool (compared to the engine compartment) fuel to the engine, vs just an engine drive pump sucking fuel the entire length of the fuel system, can help to greatly reduce the possibility of vapor lock. This is the same reason most cars for many years have had a fuel pump located in the fuel tank.
WingedFrog
Well Known Member
I totally agree with Scott's (which for a change is also Van's) point of view but... it's not a good reason not to have a switch for the fuel pump! Yes, I always fly with the fuel pump on and yes if I was using the fuel pump switch as I did with the Sport Cruiser I would regularly forget to switch it on or off at the right time (with Sport Cruiser it's on for take off and landing). However I got fed up hearing this whining when working in the hangar with the Master Switch on. Tired of removing/inserting the fuse I installed a switch/breaker just on the side of fuel valve above the center tunnel where it's easy to pick the wire feeding the fuel pump. My hint to control this switch that you cannot see when sitting in the plane: up is off, down is on just like the fuel valve. Do it! It will take you no more than 10 minutes but pick the right red wire, there are two of them down under
!FWIW, I also installed a toggle switch with a safety cover to isolate the fuel pump when I don't want it running. It's in the same location as Jean-Pierre's, and also with up-off and down-on (default). Works well and is easy to install in that location. I'll keep the pump on normally, but it's handy to be able to turn it off easily when necessary. I understand Scott's point about simplicity, and it does mean something else to think about in the cockpit, but I like it.
