fuel pick ups

stevewiz · Post by **stevewiz** » Sat Aug 09, 2014 3:21 pm

Quick question, We are building the fuel tanks and I am wondering if we need to build the “inverted fuel line pick up option” or just go with the standard vans fuel pick ups. Our goal is not long inverted flights but will do rolls or loops. Thanks

Post by **bullojm1** » Sat Aug 09, 2014 4:35 pm

Steve,

On if you plan to do sustained inverted flight will you need the flop tubes. This means you will also need a fuel injected engine and also an inverted oil system. For positive G maneuvers (Loops, Aileron Rolls, Hammerheads, Barrel Rolls, etc..) the standard pickups are all you need. It's what I use. Furthermore, the inverted tubes stiffen over time and have to be replaced every few years. Another reason my vote is against them if not 100% needed.

stevewiz · Post by **stevewiz** » Sat Aug 09, 2014 4:58 pm

Thanks Mike that's what we needed to hear. On a second note sorry we missed your plane at EAA. We searched on Friday early PM but could not locate you.

captain_john · Post by **captain_john** » Sat Aug 09, 2014 8:00 pm

Steve, Mike is rather elusive. He mighr appear at the strangest places at the most unusual times. As far as your pick up tubes go, I installed one in my left tank only. My intention was to use this tank whenever I was horsing around. I do not have inverted oil, but My thought that I did not want to come unported at an inopportune time.

CJ

painless · Post by **painless** » Sat Aug 09, 2014 8:37 pm

Unported CJ? I thought you preferred India Pale Ale??

Post by **bullojm1** » Mon Aug 11, 2014 9:53 am

stevewiz wrote:On a second note sorry we missed your plane at EAA. We searched on Friday early PM but could not locate you.

Steve,

We headed out Friday around 1pm to beat some of the weather that looked like it was headed towards Oshkosh.

captain_john wrote: My intention was to use this tank whenever I was horsing around.

I horse around plenty in my RV and have never had the engine sputter because of lack of fuel. Slight loss of oil pressure is another thing! The oil will depart from a location in the sump that the oil pump can pick it up well before the fuel in the lines will run out. Basic volume measurements - An estimated 10' of 3/8" OD Tubing (assume 1/4" interior diameter) will hold 0.105 gallons of fuel. Assuming your engine will be running at about 25 squared, consuming 12 GPH (or 0.2 gallons per minute). So you have 30 seconds of being in negative G's before the fuel runs out of the lines. And this is being conservative since the fuel filter typically holds a descent amount of fuel.