Fuel tank in front question.

[Jlwright]

I would like to build an aluminum fuel tank and mount in front of the panel like Sam's XL. I realize I am putting weight out in front of the CG and it seems to work fine for Sam.
Does it make any difference on the weight of the pilot concerning the CG. I weigh 145 lbs and wonder if that will make the plane handle any different than it would with a heavier pilot. I'd hate to get all done and find I have a nose heavy condition but in my mind it shouldn't make any difference as the pilot sits close to the CG. Deep thoughts.

[Sam Buchanan]

I would like to build an aluminum fuel tank and mount in front of the panel like Sam's XL. I realize I am putting weight out in front of the CG and it seems to work fine for Sam.
Does it make any difference on the weight of the pilot concerning the CG. I weigh 145 lbs and wonder if that will make the plane handle any different than it would with a heavier pilot. I'd hate to get all done and find I have a nose heavy condition but in my mind it shouldn't make any difference as the pilot sits close to the CG. Deep thoughts.

Jim, I think you answered your question.  

The XL seems to have a pretty wide CG envelope.

[Jlwright]

That's what I get for thinking out loud.

[leshoman]

I fly at about 210 and there is a difference between full tank and empty regards stick forces to keep it from pitching down slightly.  The only time you notice it is if you want to fly hands off. I would believe at 145 pounds you would notice this effect more.

[Sam Buchanan]

I fly at about 210 and there is a difference between full tank and empty regards stick forces to keep it from pitching down slightly.  The only time you notice it is if you want to fly hands off. I would believe at 145 pounds you would notice this effect more.

The elevator trim tab on XL-58 is set for hands off with about 3/4 full tank which means it might pitch up (hands off) ever so slightly as fuel burns off. Reduce power a few rpm and it's back in trim. 

However, I rarely fly the plane with less than two gallons so it barely ever gets out of trim.

[Jlwright]

Sounds like a non issue. Thanks.

[weasel]

Consider that if you mount the tank in the nose you probably are stuck with either running the updraft zenith or running a fuel pump.

If you want to run dual carbs they will likely be higher than the bottom of the fuel tank.

[leshoman]

I am running dual mukuni carbs and no fuel pump there is 6" drop between fuel outlet a d top of carb.  That is what i am td you need to have enough head pressure to carb  have 40 hrs 
D

[Jlwright]

I am planning on a Scott Casler 37HP with a single carb at this time.

[weasel]

I am running dual mukuni carbs and no fuel pump there is 6" drop between fuel outlet a d top of carb.  That is what i am td you need to have enough head pressure to carb  have 40 hrs
D

Nice.   Would be interested in pictures of your set-up.

On the Classic the bottom of the tank is below the crank.  Jo thought I just HAD to have a dual set up but was no practical way to work it.

[Dan_]

I am running dual mukuni carbs and no fuel pump there is 6" drop between fuel outlet a d top of carb.  That is what i am td you need to have enough head pressure to carb  have 40 hrs
D

    Les,
    I would be sure my tank vent was always pointed into the slipstream, to ensure the tank stayed pressurized... With low fuel you could get starvation.

[Sam Buchanan]

I am running dual mukuni carbs and no fuel pump there is 6" drop between fuel outlet a d top of carb.  That is what i am td you need to have enough head pressure to carb  have 40 hrs
D

    Les,
    I would be sure my tank vent was always pointed into the slipstream, to ensure the tank stayed pressurized... With low fuel you could get starvation.

Those of us with cowl tanks are venting through the filler cap where the "fuel gauge" wire protrudes......like a J-3.





Granted, I don't run the fuel down to a low level in my tank (why would I?) but in three seasons of flying there have been no performance problems.

[Sam Buchanan]

I am running dual mukuni carbs and no fuel pump there is 6" drop between fuel outlet a d top of carb.  That is what i am td you need to have enough head pressure to carb  have 40 hrs
D

Nice.   Would be interested in pictures of your set-up.

On the Classic the bottom of the tank is below the crank.  Jo thought I just HAD to have a dual set up but was no practical way to work it.

I was concerned about head pressure when I built my cowl tank since mine was the first on an Eagle. My 45 engine was delivered with a standard VW fuel pump and that is what I ran for the first few hours. But in the course of chasing oil leaks that first year, one of which was from the shaft in the pump, I removed the pump and have had no fuel delivery problems since.

Turns out the oil leaks were due primarily to the crankcase not being vented sufficiently. Casler has since redesigned the vent system and it now works as intended and the engine is bone dry. But the VW pump works just fine on our engines and will provide plenty of fuel pressure if someone is concerned out running dual carbs with a cowl tank.

[leshoman]

My vent is just like Samms