Spencer Original Design

[tallank]

I used a Shorai LiFe battery for 4 years in my motorcycle before I put one in my RV6. Been in the RV6 for around 4 years now with zero problems. It weighs 4 lbs compared to the Odyssy's 16 lbs and cranks the Io360 with 9 to 1 compression a whole lot better. It is behind the firewall. Plan on using one in my Kitfox5 project. Probably have it on the engine side of the firewall. Like the suggestion of using an isolated box with an air vent.

 

[Rockiedog2]

So finally got the proseal and got the tank sealed up. Got the leaks stopped up with the balloon and soapy water technique. It's in the plane now and full of gas for a while to see if any leaks develop. The 2G Mrs Carlson tank weighed 2#, the new 8G one is 5#. Mrs Carlson's is probably .050; this new one is 050 ends and 032 walls and top. Flanged outside and assembled with Zenith pop rivets. The few rivets that had to go inside are closed end 1/8" pop rivets. Lotta work in that little tank. We'll do a new empty weight/cg next.

 

[Rockiedog2]

How do we zoom in on pics when they're paired together like that?.

 

[BJC]

On my iPad, just put fingers on the photo and spread them.


BJC

 

[Rockiedog2]

Desktop here

 

[rv7charlie]

CTL + to zoom big; CTL - to zoom small.

Good to see that you still remember some RV skills.

Tank looks great, but I'm afraid filling it will be a bit slow through either of those holes....

 

[JohnB]

Joe, Is this additional tankage so you can visit Leonard and I nonstop?

 

[Rockiedog2]

Hi JB
I've about quit making trips it seems. Had to have a project to get my mind off current events. Another experiment, like most stuff around here. The plane would already make that trip nonstop but not the PIC. They had a big discussion about catheters and relief tubes and such and all the time I'm wondering why not just land and pee. I dunno. You still booked up welding fuses?
Charlie yeah it takes a while to fill thru that 3/8 line. Several options but I'm not gonna tear into the existing plumbing before I fly that tank around a while and see if I can live with it. It takes up a lotta room and I don't like being jammed in. For local can just run header fuel only but if on a trip and trying to make a quik turn around it could be a problem, depending. Gravity fill from a wing tank thru a 3/8 AL tube. Thought I would do a flow test and then add a 4psi pump inline and see what that did. I expect somebody here knows how to calculate that.

 

[rv7charlie]

Boy, I was kidding about the little port; I figured I just couldn't see the actual fuel filler neck in the pics.

Facet cube claims pump about 25-30 GPH at design pressure, according to their website.

If you decide to pressure feed it, don't forget about vent size. I was planning on using a high volume fuel injection pump as a transfer pump on the -7's aux tanks, until a friend who's a research scientist (he tests *everything*) pointed out that if you fill a tank completely, and it has a typical -4 vent tube that's a few feet long, the pressure in the tank will go up to around 10 PSI as soon as the vent tube fills. (Tank rupture in short order.) It wouldn't be as bad with a Facet, but it might be worth an experiment to be sure it can't get up to the max of the Facet, which still could damage the tank.

Just one more thing to worry about...

Charlie

 

[Rockiedog2]

Sump cutout. Yeah there's some extra holes in there.

More sump

Inside. There's some wide angle effect there. It's now whopsided like it looks.


Index marks. Not for stress riser freaks



Homemade fitting. 1/4PT ell drilled and tapped for 1/8PT drain port. Junk box treasure. Don't ever throw anything away.



How I get my proseal so neat. Special tools. Toothpick, match, piece of cardboard and delrin hand chisel/spreader.


Hangar guard on strict duty.

 

[Rockiedog2]

Mr Mod
Somehow I posted that indexer pic twice. Please delete the extra one. TY

 

[Rockiedog2]

Boy, I was kidding about the little port; I figured I just couldn't see the actual fuel filler neck in the pics.

Facet cube claims pump about 25-30 GPH at design pressure, according to their website.

If you decide to pressure feed it, don't forget about vent size. I was planning on using a high volume fuel injection pump as a transfer pump on the -7's aux tanks, until a friend who's a research scientist (he tests *everything*) pointed out that if you fill a tank completely, and it has a typical -4 vent tube that's a few feet long, the pressure in the tank will go up to around 10 PSI as soon as the vent tube fills. (Tank rupture in short order.) It wouldn't be as bad with a Facet, but it might be worth an experiment to be sure it can't get up to the max of the Facet, which still could damage the tank.

Just one more thing to worry about...

Charlie

I thought I would test a Facet 4psi that's in the junk box. The tank has a -4"maintenance vent" is what I call it that has to be open to fill the tank thru the wing tank line. It starts out as a -6 then down to a -4 which I can upsize to a 6 all the way but might now be enough. The PIC can tell when the tank is full cause there will be a big puddle of gas under the plane. Yeh, the vent line drains into the gear leg fairing and out thru the wheel pant. I got an old homemade tank here made outa 016 think I'll hook it up to and see if it blows it up. Think I'll use water.

 

[rv7charlie]

I think that my friend just ran a length of -6 off the pump, installed a T fitting on the other end, and installed a pressure gauge on one leg & -4 on the other leg, with the -4 the same length as the vent line in the plane. (RV, so i guess he ran it uphill & then down, but I doubt that's of any consequence vs the flow resistance of the line itself.) You could probably get a reasonable approximation by just T-ing the pump output for the gauge, and then X feet of -4 to simulate the vent line.

Remember, his test was with a fuel injection pump (~40 psi-capable). Might not be an issue with a 4 psi facet, but I'd want to know before risking a tank. Even 3 or 4 psi might be marginal for damage risk. IIRC, we're told to keep pressure under about 25" of water (~0.9 psi) when testing RV tanks, so that might be my risk threshold....

Charlie

 

[Rockiedog2]

You guys will know this for sure. Pretty basic stuff.
Figuring the wing area, is the fuselage portion counted or not. I've read it both ways from supposedly credible sources. I've counted it before when trying to make stall speed for instance but have always had doubts that it did much in the way of lift except maybe in a plane like the Tailwind with the belly shape like it is.

 

[wsimpso1]

Mr Mod
Somehow I posted that indexer pic twice. Please delete the extra one. TY

Just found this. Deleted the double.

 

[wsimpso1]

You guys will know this for sure. Pretty basic stuff.
Figuring the wing area, is the fuselage portion counted or not. I've read it both ways from supposedly credible sources. I've counted it before when trying to make stall speed for instance but have always had doubts that it did much in the way of lift except maybe in a plane like the Tailwind with the belly shape like it is.

When you are figuring wing area, yeah, even the part "buried" in the fuselage counts. Tail too. The lift acts the same if you wrap up the center in fuselage or not. Sounds weird, but true. Remember that the wing is grabbing the equivalent of a cylinder one wingspan in diameter and bending it down to make lift. That big a chunk of air and the pressure field around the wing does not get readily messed up by a fuselage, even on the Super Guppy and Beluga airplanes. When you look at pressures on the wing and fuselage, the pressures are not quite as strong over the fuselage than on the wing proper, but the pressure pattern is also spread out some over the fuselage - works out to about the same lift. Yeah, there is more drag because of interference, but the lift is pretty much unaffected.

Billski

 

[Rockiedog2]

Thanks Bill. So I did right including that in mine then. No bending rules for the stall speed formula. Turns out it didn't matter anyway cause it stalls well under the LSA limit.

Well, the tank experiment was a failure. When I got it in there so I could eyeball it good the hair on the back of my neck started standing up and the hide started crawling. I had measured and eyeballed it with how much head in mind and was wary of the thing. So got it in there and plumbed and did a 3 point flow test with 5 gallons in the header. 12 GPH. No way. Pulled it out on the strip and fired it up and sat there at 1600 rpm for a while and ok then taxied up on the driveway slope and it ran a couple minutes and quit. Did that a couple x and that was enough for me. It's coming outa there. That 8G needs to be mostly usable and it's not. The MS Carlson 2G header doesn't matter cause 2G and we're down to min fuel and sposed to be on the ground. And it's higher so would likely feed at low power in a descent to landing. I could put a 4psi facet pump on that header but with no engine driven pump it's just a matter of time before that pump doesn't get turned on before takeoff. And besides I go by what TFF said...if we need a fuel pump we need two. I don't want all that stuff in there so the tank is coming out. Death trap. Fuel systems are like rattlesnakes, they'll bite you.
Well, it was a good experiment and we got more wall art.

 

[Pops]

A fuel system is life or death. Why I copied Bob Barrows fuel system for the SSSC and the JMR. It is tried and proven and I like it.
Bob uses the same fuel systems on all of his designs. I even used the Bearhawk vented fuel caps on the wing tanks.

 

[Rockiedog2]

A fuel system is life or death. Why I copied Bob Barrows fuel system for the SSSC and the JMR. It is tried and proven and I like it.
Bob uses the same fuel systems on all of his designs. I even used the Bearhawk vented fuel caps on the wing tanks.

can you put a drawing or pics up for us Pops?

 

[rv7charlie]

Was the issue lack of head to feed the carb? If you really need the fuel, you *could* consider reversing functions (though I'd want a decent fill port on the new tank). If the lower tank is pumped into the upper, and the upper feeds the engine....

Sensible monitoring of wing tank volume could allow a single transfer pump; if it fails, land before fuel exhaustion.