A ferry tank would only be used when the back seats are out. I'll take another look at the BH aux tanks but I think they are overkill for my mission and I don't want to carry that extra 30 or whatever pounds around needlessly.

I have zero personal experience with fuel inside the cabin of an airplane, but a friend had a 172 with an O&N aux tank installed--it fits on the floor of the baggage compartment and is essentially the same as Cessna offered as an option for several years. It had a filling port on the passenger side of the fuselage and was vented outside. He had plans to fly the airplane to Alaska but never did. All it did was take up baggage room. He never complained about smell, but he sure complained about loss of baggage room. I never flew with him, so I can't comment on lack of smell, but just looking at it, his baggage area was diminished quite a lot.

When I planned my small boat trip (The Ultimate Small Boat Adventure, still available from Barnes & Noble, Amazon, only $15.95), I decided to add an aux tank to the boat. Although I was very careful and followed USCG requirements including an outside filling port and vent, and there is no discernible leakage, it still smells a little "gassy" for awhile after first filling the aux tank. I plumbed it so that when I drew from the aux tank by switching a manual valve, it automatically changed the gauge to read the aux tank level.

I also added a port to plug in portable gas cans, the typical plastic boat cans, and carried two of those on the trip, outside on the swim platform. I was glad to have the aux tank and drew from it a few times, but I never had to use the portable cans, although they gave me some comfort "just in case".

I've given some thought to having Flint aux tanks installed in my airplane's wings, but I so seldom use the capacity I have, that the expense just can't be justified, and the loss of useful load would be annoying.

All that FWIW. Your airplane, you're building it, your decisions, but I think you've gotten some good advice.

Cary

I personally would add a dedicated fitting to one main tank. This would allow me to add fuel to that tank while burning fuel out of it without the risk of air entering the fuel supply. Use a transfer pump with a check valve to keep fuel from flowing back from the main tank to the aux tank. I would mount the pump and an Aux tank fuel quantity indicator on the aux tank. You would need a backup manual (non electric fuel pump) to transfer fuel do to the aux fuel being equal to your main fuel and if unable to complete the transfer you may not have enough fuel to return to your departure spot or available alternate. You could disregard this if you were overflying airports or only using it to tanker fuel, not to extend range. For the limited times you will be putting the tank in and out I would just cap the line. The check valve will keep fuel from running from the main back down the line when you remove the cap to connect the flex line from the transfer pump output.

At this point in your build all that you need to complete is the extra fitting in the tank and possibly the line and check valve (which you would want close to the termination point so that when you take the cap off a minimum amount of fuel would leak out) to reach the cabin sidewall.

Tim

I've been using a ferry tank type system to extend my range for 20 years, first rule is: don't crash. I've run through the various crash scenarios......and really don't feel that much more at risk then I already do with all the fuel carried right up by my head in the wing tanks. Sure, in a perfect crash situation, you rip the wings (and their fuel tanks) off and come to an uneventful stop, safe in the fuel less fuselage. But it seems like most crash pics show the wings still on the plane and crumpled up pretty bad, I try not to crash and I feel the risk is acceptable. To each his own there, let's face, carrying fuel is dangerous always no matter how we do it. In my case I'm only talking 8 or 9 gallons.

Run the vent outside and there's no smell.Second rule is ASAP, when the mains run down enough, transfer the fuel carried in the ferry up. That way most of the time I flying around with an empty ferry tank. I like having the extra range when needed, and not the extra weight all the time of more tanks in the wings. Also in my case, I use the ferry tank to get mo mo gas (not a typo, just a bad play on words) as it comes in and out in seconds. It's near enough to being on the CG to not be a huge factor in loading. I simply teed off the bottom of my 3 gallon header tank, which leads to the engine and is fed by the mains (both mains, all the time). I don't care if the fuel pumped by the ferry is going directly to the engine or up into the mains or some combination of both, it doesn't matter.

I have a panel mounted switch with a indicator light showing I'm pumping fuel, and a under my seat but reachable valve, in theory the valve isn't even needed if the built in check valve on my quick disconnect is working, it's just a backup to the check valve. This check valve is bypassed in effect when the disconnect is plugged in, both ends of the disc have auto shut offs. Not aircraft hardware, but marine, good enough for me.

I use mine thusly: I fly along, and as soon as I can, transfer MOST but not all of the fuel in the ferry. Then I fly some more.......knowing I if I screw up my range "calculations", I still have an hour or so in the ferry tank. I can totally run out my mains, the instant I switch the transfer pump on the engine restarts, I tried it as a test once. Then I can fly some more, only when I see the fuel in the 3 gallon header tank dropping (via it's sight gauge), down to the 1 gallon mark (the tank is tapered, 100% usable) do I really seriously start thinking of ;landing somewhere. Kidding.....except for a couple times, but I damn well knew for a fact exactly how much fuel I had so could plan accordingly. If I ever report I actually had to dead stick it in somewhere due to fuel exhaustion, somebody kick my ass!

One thing I will say relative to safety, I really am liking my expensive Nauta fuel bladder (400 bucks for 9 gallons). It is totally dribble and smell free, and requires NO venting. Like the ABW bush bags, as it empties it flattens out to nothing. It has two handles making it very easy to carry and lash down. I think it would take one hell of an impact to rupture, much more then a aluminum tank. If I was you Whee, I'd sell that tank you have, and go ahead and put the few extra fittings in your system while building, and then later pony up and buy a Nauta, a bit over 500 for a 18 gallon, they get cheaper per gallon the bigger they get. they make any size you want.

My Aussie mates use collapsing "Turtle Pacs" when crossing the Pacific in light aircraft. I.e. Cessna 182, Navajo, Caravans (amphibs) etc..

They carry the whole rig... Tanks, plumbing, pumps in a check in suitcase.

http://www.turtlepac.com

FWIW I've never seen that big of an in-cabin aux tank-- O&N and Javelin both used to make baggage-compartment aux tanks for Cessnas but they were in the 15-20 gallon range. I've got an old 1979 Air Progress magazine with a pirep on a turbo'd 1953 C180, says it has a 17-gallon aux tank mounted "in the ceiling between the wings". Never heard of something like that before and no manufacturer given.
FWIW it doesn't specify but from a comment in the article ("2550 redline") it sounds like it has a 470-J engine. Manual wastegate on the turbo but limited to 29-1/2" manifold pressure so it's intended for turbo-normalizing use.

hotrod180 wrote:FWIW I've never seen that big of an in-cabin aux tank-- O&N and Javelin both used to make baggage-compartment aux tanks for Cessnas but they were in the 15-20 gallon range. I've got an old 1979 Air Progress magazine with a pirep on a turbo'd 1953 C180, says it has a 17-gallon aux tank mounted "in the ceiling between the wings". Never heard of something like that before and no manufacturer given.
FWIW it doesn't specify but from a comment in the article ("2550 redline") it sounds like it has a 470-J engine. Manual wastegate on the turbo but limited to 29-1/2" manifold pressure so it's intended for turbo-normalizing use.

My friend's in his 172 was 18 gallons, on the floor of the baggage area.

Cary

Whee,

I'd still consider a belly tank of some sort. Easy to install, easy to drop. It's not in the cabin, and the CG will be a little further forward than that tank. And, it doesn't occupy baggage space. You and your dad are going to need some baggage capacity for that AK trip, and you'll find that ferry tank to be seriously in the way. Also, in addition to the plumbing to get the fuel out of it to the wing, you'll also need a filler neck that comes out the side of the plane and a vent. Vent is pretty easy, but those others are going to be there all the time, tank or not installed.

I'd start looking for a Cunningham belly tank for a cub or one of the Cessna belly tanks. Or if you want to play with fiberglass yourself, make one in two pieces, then join them, but down the road when the plane is complete and flying. In the meantime, add the plumbing to pump fuel from the belly tank up to the left wing into the plane as you build.

The old Cunningham tanks that I used were 36 gallons, but they made 72 (or so) gallon tanks as well. Might be able to find one of those and cut it down some.

I just don't see how you're going to make that tank a clean installation that isn't going to be seriously in the way, and the accommodations for it will be in the way and pretty ugly when the tanks not installed.

But, it's your plane, obviously.

MTV

Don't worry guys. I'll ditch this tank and use it for long trips in the boat and to fill the plane with mogas like I originally planned.

Been a bit of a rough week and I'm feeling a little beat up. I appreciate you guys looking out for me and helping me not make noob mistakes. Think I'm going to check out, put my head down and out of the line of fire, get my boat project out of the way and make some good progress on the plane.