During my self imposed 4 month period of website avoidance a private message came from Mr. Modena from Brazil about my fuel system that allowed us to fly our RV-6A from Santa Ana, California to Fayetteville, Arkansas with only one fuel stop in Albuquerque, New Mexico. I responded several months later but evidently he gave up waiting for the answer so here is the information and I hope he gets it.
The tanks were manufactured by a man named Farn Reed in Grants Pass, Oregon. I learned via this web site that he died in an aircraft accident and the tanks are no longer available. They are all aluminum and contain a total of 17 extra gallons of fuel. They attach to the end of the wing with three large diameter threaded steel rods and many screws and platenuts similar to the normal tip attachment. These extend the wing span 1.5 feet and rule out aerobatics. There is a conduit through the tanks for wiring of tip lights. Jon Johanson of Australia used to sell fiberglass tip tanks that did not increase the span but I hear they are no longer available either. If I were doing it today I would add leading edge tanks outboard of the existing tanks. I REALLY like the extra range and couldn't care less about aerobatics so we make a good match but the drag of the extra span is a little bit of an undesirable side effect. Anything less than the capacity of these tanks is a complication without adequate compensation in my opinion. In my cross country flying I burn half an hour out of the tip tanks during the first tank switching cycle (always takeoff on a main because the engine will die if you climb out on a tip tank that is not full and the fuel shifts to the rear at the high angle of the climbout). I plan .8 hours out of each tip tank and 1.5 hours out of each main divided into .5 hour weight control segments. To get the final available fuel out of the tanks I fly the last segment in each tank with my hand on the valve for the last 18 minutes or fuel pressure decay which ever comes first. The tips are starved but the mains should have 24 minutes remaining at my 10 gallon per hour fuel burn. In last years AirVenture Cup Race I essentially went through all of the fuel in all four tanks (55 gallons) in less than 2.5 hours so results definitly vary. I alway fly wide open throttle leaned rich of peak 2450 RPM in normal cruise 2700+ in races.
I hope Mr. Modena gets the information and my apology for not responding sooner. However, I intend to get back on the wagon soon - this is an addiction you know.
Bob Axsom
The tanks were manufactured by a man named Farn Reed in Grants Pass, Oregon. I learned via this web site that he died in an aircraft accident and the tanks are no longer available. They are all aluminum and contain a total of 17 extra gallons of fuel. They attach to the end of the wing with three large diameter threaded steel rods and many screws and platenuts similar to the normal tip attachment. These extend the wing span 1.5 feet and rule out aerobatics. There is a conduit through the tanks for wiring of tip lights. Jon Johanson of Australia used to sell fiberglass tip tanks that did not increase the span but I hear they are no longer available either. If I were doing it today I would add leading edge tanks outboard of the existing tanks. I REALLY like the extra range and couldn't care less about aerobatics so we make a good match but the drag of the extra span is a little bit of an undesirable side effect. Anything less than the capacity of these tanks is a complication without adequate compensation in my opinion. In my cross country flying I burn half an hour out of the tip tanks during the first tank switching cycle (always takeoff on a main because the engine will die if you climb out on a tip tank that is not full and the fuel shifts to the rear at the high angle of the climbout). I plan .8 hours out of each tip tank and 1.5 hours out of each main divided into .5 hour weight control segments. To get the final available fuel out of the tanks I fly the last segment in each tank with my hand on the valve for the last 18 minutes or fuel pressure decay which ever comes first. The tips are starved but the mains should have 24 minutes remaining at my 10 gallon per hour fuel burn. In last years AirVenture Cup Race I essentially went through all of the fuel in all four tanks (55 gallons) in less than 2.5 hours so results definitly vary. I alway fly wide open throttle leaned rich of peak 2450 RPM in normal cruise 2700+ in races.
I hope Mr. Modena gets the information and my apology for not responding sooner. However, I intend to get back on the wagon soon - this is an addiction you know.
Bob Axsom
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