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Incentive to never use 100LL

N

NinerBikes

Well Known Member
Has anyone figured out a way yet, short of filling your RV-12 Legacy model fuel tank at a snail's pace, to not burp AV gas 100LL, all over the outside of your plane, with the fuel nozzles that come on Aviation fuel pumps.

The nozzle is straight, the filler neck is curve, it's just a bad combination.

I've no problems filling it with Mogas, but those straight nozzles on AV gas pumps are a sloppy royal PIA, that's really messy most of the time, even when first starting pumping fuel. The stuff burps back everywhere.
 
The main cause of splash back is the air in the tank exiting through the same long tube that fuel is flowing in. The faster the fuel goes in, the faster air has to come out (and get past the fuel that is coming in).

So it has more to do with the high flow rate of aviation pumps than it does with the shape of the filler tube.

What seems to work best (regardless what type of pump you are using) is to only insert the nozzle tube into the filler opening a couple of inches and keep the flow rate to the low end of what the nozzle will do.
 
It doesn't help that most GA fuel pumps seem to pump at 5,000+ gph. Even in my -7 with no filler neck I usually only pump about half speed and I still need to tease the trigger once the fuel passes the big holes in the rib to let the vent catch up and get the fuel from the outboard bay into the rest of them. the last 3 gallons takes about as long as the first 18. like Scott said the limiting factor really is that you can't put fuel in any faster than the air can escape.

At my previous location I had a private tank with a pump speed more like the auto pumps and it was so much nicer to fill than the monsters at most airports.
 
Well, advised ferry to go slow pumping fuel in.

Hopefully this will be less a problem once my bird reaches it's new home late next week. Kind of did this bass ackwards, buying the plane before I know how to land it, or experienced enough to get it home myself and have everything stay in one piece.

But I knew I didn't want to rent, and I knew I wanted to take lessons and fly in my own plane, with a plane without a squawk list a mile long, or a rental 172 with 8000 + hrs on the air frame, landed hard by hundreds of students and renters. You only get that with ownership.
 
Being an amputee I find just about anything related to airport refueling equipment annoying. Do we really need the huge & heavy hose and nozzle that also weighs a ton on the 100LL pumps? Are we trying to gas up the space shuttle?
 
bnt83 said:
Being an amputee I find just about anything related to airport refueling equipment annoying. Do we really need the huge & heavy hose and nozzle that also weighs a ton on the 100LL pumps? Are we trying to gas up the space shuttle?
Click to expand...

Haha, so true!
 
bnt83 said:
Being an amputee I find just about anything related to airport refueling equipment annoying. Do we really need the huge & heavy hose and nozzle that also weighs a ton on the 100LL pumps? Are we trying to gas up the space shuttle?
Click to expand...

Well they do have to make the aviation hose "abrasion proof". It gets the worst treatment by pilots who don't care. Same with the ground cable. I always walk it back to the reel instead of just letting it go to get wrapped up and slammed into the stop. :eek:

-Marc
 
Tank Build Heads Up

odens_14 said:
It doesn't help that most GA fuel pumps seem to pump at 5,000+ gph. Even in my -7 with no filler neck I usually only pump about half speed and I still need to tease the trigger once the fuel passes the big holes in the rib to let the vent catch up and get the fuel from the outboard bay into the rest of them. the last 3 gallons takes about as long as the first 18. like Scott said the limiting factor really is that you can't put fuel in any faster than the air can escape.

At my previous location I had a private tank with a pump speed more like the auto pumps and it was so much nicer to fill than the monsters at most airports.
Click to expand...

When I built my RV9 tanks, I enlarged the vent hole in each rib to 5/8", I think. It seems many have done this to overcome the slow fill speed as the tanks get full.
 
NinerBikes said:
Well, advised ferry to go slow pumping fuel in.

Hopefully this will be less a problem once my bird reaches it's new home late next week. Kind of did this bass ackwards, buying the plane before I know how to land it, or experienced enough to get it home myself and have everything stay in one piece.

But I knew I didn't want to rent, and I knew I wanted to take lessons and fly in my own plane, with a plane without a squawk list a mile long, or a rental 172 with 8000 + hrs on the air frame, landed hard by hundreds of students and renters. You only get that with ownership.
Click to expand...

This is what happens to the Lexan rear window in the older -12s if you spill any kind of fuel on it.
i-xrkFCT9-L.jpg

The new plexiglass window probably is better in this regard but I would still use care.

This is what my buddy and I do when we fill up using aviation nozzles:
i-gwFmpnq-L.jpg

This does get some strange looks from the line-boys.
 
I?ve splashed avgas without any problems but ruined a window with unleaded. Now use a rubber mat with an anti-slip sheet underneath to stop it sliding off. Roll them up together - sits nicely behind the passenger seat.

Jack
 
My plane is now in it's new home. 20.2 hours from Ridgeland, SC to WHP in CA, without the ferry spilling drop, it seems.

Not sure what the turtle deck or rear canopy what ever it's called on my RV-12 is made out of, but it's tinted dark.

It's official now, I am a new Student Pilot, training in my own RV-12. I now get to log hours in my log book. IACRA form for the FAA is complete.

N72DJ will get a steady diet of premium Mogas from here on out. Only real option to buy Mogas was at Skywest, SE of Midland TX, where 13.5 gals got added to the remaining 6.3 of 100LL in the main, and another 4 of Mogas got added to 2.5 in the Aux tank, to make 91 or better fuel. At $2.33 a gallon for the Mogas, the blending in route was a good break in flying for the ferry, and worth it.

The 26.5 gallons of total capacity fuel really came in useful for the cross country. Easy to extend your run time to just under 4.5 hours and still have 40 to 45 minutes of reserve, or 4 gallons left for a safe go around. The extra distance made fueling stops for best priced gas from SC to TX much easier to manage.

I haven't worked out all the measurements yet, I think my plane has the prop pitched for cruise, it does not climb the fastest, compared to my friend Bob's N836BL, but saw a very consistent 5 gallons per hour burn rate.
 
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What/how did you set up an aux tank for the flight? Just a standard jug used on the ground, or an actual cross-feed while en route?
 
n74846 said:
What/how did you set up an aux tank for the flight? Just a standard jug used on the ground, or an actual cross-feed while en route?
Click to expand...

It's a standard 6.5 gallon poly outboard motor fishing tank with send and return lines. A standard Van's electric pump was run inline on the feed line, and two bungs were added on the upright filler tube.

It works something like this: run the tank down to about 6 gallons, flip the electric switch on for 20 minutes, where you will burn almost 2 gallons when the aux pump finishes pumping dry, and you should have 10 gallons showing on the Skyview.

Some D Rings are installed in bottom of the luggage area, and then cinched tight through the handles on the fuel tan with some nylon strap.
 
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