Tank Hatch for Fancy Pants??

Hi,

On a previous thread I read about several folks who built there fancy pants with a tank hatch to allow access.

I just have some questions.

1. Did you create the hatch on the top of the fuse or bottom?
2. What did you use for a hinge latch?
3. Lastly, the kit recommends a brodak #540 3.5 ounce deep wedge fuel tank. I'd like to use the brodak #549 tank as it's dimenions are identical but features a uniflow vent over a standard vent. This would work fine accept the instructions illustrate using a standard vent with both the fill tube and overflow tube sticking out of the top and bottom of fuse. A uniflow vent bends forward instead if sticking straight up.

Did any of you solve this problem?

Any help would be very much appreciated..

Thanks in advance..

LAST EDITED ON Aug-06-01 AT 02:50 PM (EST)

1: I put the hatch on the top.
2: I glued a 1/16 ply tongue under the rear of the hatch & another one under the fixed part up front with 2-56 blind nuts. I inlet a small piece if 1/32 ply under the front of the hatch & used sunken 2-56 allen bolts to hold it on. This worker very well, but if I had it to do over I'd use short pieces of Golden Rod inner plastic tube glued in with skinny glue instead of metal blind nuts & #2 allen sheet metal screws (sand the outside of the tubing so the glue will stick first).
3: I used a 4 oz uniflow tank with all three tubes coming right out the front & plumbed them right through F1. It's a tight squeeze with a fuel filter, but you can get all the plumbing inside the nose, at least with a Fox .35 you can.
Nils

I would like to offer an alternate solution that doesn't involve a hatch at all:

Place 1/2 inch balsa cross grained between the motor mounts behind the engine, making sure the motor mounts, or at least the 1/2 inch balsa extend all the way to the wing. This, then becomes the floor for the tank compartment. And it adds enough strength to the front end of the fuselage such that you no longer need the bulkhead in front of the tank which you can now eliminate.

Now add an 1/8 inch balsa piece 1 1/8 to 1 1/4 inch above the tank floor and this becomes the top of the tank compartment. Use a tank with all tubes forward, and you can slide it in and out of the compartment for a removable tank without having to make a hatch above or below. If the compartment is made somewhat taller than the tank being used, you can use balsa shims above and below to shim it in and various thicknesses can be used to make the height adjustable in the process. We use one 1/8 inch shim, one 1/16, one 1/32, and two 1/64 and "mix and match" to get the appropriate height. Business cards can also be wedged in the mess if you need a little extra.

Put an overflow and vent tube in the nose of the plane somewhere and use plastic tubing to connect these to the tank.

If you put the engine on 1/8 inch pads and lower the engine bearers accordingly, you will allow yourself a little room for the tank to go down as well as up (or, on an inverted engine, up as well as down.)

We actually make a crutch by assembling the motor mounts and balsa between before assembling the fuselage, and this helps to jig things up quite square.

If you want to save weight, use a router to cut a 1/4 inch groove in the inside part of each motor mount and then put cross grained 1/4 inch balsa all the way across from one groove to the other. Then add a 1/8 inch piece on top of this to finish out the tank floor and that will do the job quite admirably. We have also done this by tapering the motor mount stock towards the back, but care must be taken to taper the balsa block that goes between at the same angle, so this requires a jig of itself to keep everything square in the assembly process.

Anyway, for those unaware of the above, give it a whirl on your next plane. It is simple, effective, strong, and light. A good combination.

On uniflow vents, I use a oneway valve from Kustom Kraftsmanship, (part 555,I think) so that it makes no difference which way the vent points. I often have the uniflow and the overflow coming out side by side. If I have not flown an airplane for a while, when I take the oneway and the overflow cap off to fill, I may forget which is which. Need to be more careful.