Hey Worthy, my new bird came with the Monarch tanks, both the mains and the outboards, all Monarch. 92 gallons total. Each tank has it's own filler, the outboard tanks are pumped into the main tanks whenever you decide you want the fuel. I have separate dipsticks for the outboard and main tanks. The previous owner hadn't really used the tanks much so wasn't able to tell me anything useful about managing it all, but so far it appears pretty straight forward. I like the idea of the Monarchs better than the Flints since the additional fuel is so much further inboard, but who knows how much those forces really differ in reality.

Pundy wrote: the outboard tanks are pumped into the main tanks whenever you decide you want the fuel.

The early Monarch tanks had fuel pump transfer systems... The new ones are gravity with no fuel pumps... I have one on the field with the pumps and one without. I installed the gravity feed ones.

Brian

I've flown a Cessna 170 with Flint tanks (installed inside the outboard end of the stock wing) and a Cessna 206 with the wing tip tanks (which are added onto the end of the stock wing.

With those tanks full, the airplane feels a LITTLE bit more ponderous in flight, but not that much. The procedure Flint recommends is to run one main down, then switch to the other main, and pump from the tip tank into the main that you have partially drained. Then, after running the other main down some, you again switch tanks and pump some fuel out of the other tip into that main.

It's a bit of monkey motion, and requires that you actually actively manage fuel, which a lot of Cessna pilots don't really do.

But, I've pumped one main down and pumped the entire tip tank into that main, to see how much control input you have to hold due to the weight differential. It's noticeable, but not unmanageable.

The thing I LIKED about the Flint system is that if I didn't NEED the extra fuel, I just left the tip tanks empty and operated off the mains. Only down side is a little more weight.

But, with the connected Monarch tanks, if you put gas in them, that fuel is spread out between both tanks on each side.

Same goes for contamination. The Flints are separate from mains, so if one or the other is contaminated, the other MAY not be.

MTV

That's not the case with my Monarch tanks Mike, they are pumped from the outboard tanks into the inboard/main tanks, just like you describe the Flints. There's a one way valve so there's no backflow into the outboard tanks. I have 4 filler necks on the top of my wings, 1 for each tank.

Same for my Monarch’s on ‘56 C180. Aux pumps to mains. 4 caps. Love them.

I know, but you have an older version apparently, see Brian’s post above.

MTV

Ah, sorry, I didn't see that post. Bummer that they switched the pump system.

Would be easy to block off an outlet and inlet and then install a pump.

How (specifically) are the old aux tanks set up? Are the tanks fiberglass?

slow18 wrote:Would be easy to block off an outlet and inlet and then install a pump.

How (specifically) are the old aux tanks set up? Are the tanks fiberglass?

Then you would need field approval. Sounds like a really expensive nightmare...

Maybe to some.

Find a airframe engineering representative. Use data from old monarch tank STC with deviations. Don’t deal a bit with FSDO. I bet it’s doable.

slow18 wrote:Maybe to some.

Find a airframe engineering representative. Use data from old monarch tank STC with deviations. Don’t deal a bit with FSDO. I bet it’s doable.

Maybe…..let us know how it works out.

MTV

I know Hartwig will not support guys with the Barton designed STC’d tanks. I have no clue how the electronics are set up. Can someone post a pdf of the old tank design STC and any pertinent drawings/info? Here’s the new one: