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Ballast Compartment |
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The plans suggest that you can build a ballast compartment
forward of F-0. Using that idea, and, a thought I had about how to
make the door and flange to support it, I proceeded as follows. First, I
laid out the size and shape of the ballast compartment door to match with
and flow nicely with the nose door which it shares the top of the nose of my
plane with. |
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Having done some earlier preparation for this, this foam
needed to be removed. This foam doesn't extend all the way to the
bottom of this space, since my ballast compartment bottom was a second
bottom, if you will, below NG-31. I sort of have two NG-31s, one in
the standard location, with the ballast compartment hole in it, and a
second, about an inch and a half below that one, with aluminum slugs in it
for the nose lights. Anyway, after cutting out the door I needed to remove
the foam. Start digging/carving and... |
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Pretty soon you have this. The hole in the 'top'
NG-31 established the size for the bottom, the hole for the ballast
compartment door the top, I simply carved and sanded the foam for a smooth
blend between the two. |
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To make the flange that will support the ballast
compartment door, or BC door, I put plastic wrap on the nose then covered
that with peel ply and 2 layers of wetted out BID. I had wet these
layers out on the workbench, then, worked them to shape on the nose to keep
the drip issues down to a minimum. This flange blank is way bigger
than it needs to be, of course. |
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Given that I had already cut out the door and removed the
foam before I tried the layup above, I had to put some toothpicks in the
foam to support the door for the layup. Do your flange blank after you
mark the BC door but before you cut it out, please. This was
backwards. |
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I created an AutoCAD drawing of the flange, complete with
nutplate locations, using the dimensions of the door I had marked and cut
out. Sure, it curves, in two directions actually, but the shape and
size will still be right. |
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After trimming the BC door to its approximate size, I
spray-glued the pattern on, the printed AutoCAD drawing of course. |
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Next it was time to cut out the space in the nose for the
flange. I used my Fein Sander tool
for this, with a small square blade attached that makes it easy to get into
those tight corners. I needed a slot, 2 ply BID thick, about 3/8" inch
deep all the way around. |
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Here's the door flange blank installed into the slot made
in the step above. You have to cut the flange to get it in, like a
split washer, one cut on one of the longer straight edges. The blank
has been cut to its basic shape, but not to its final shape. |
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Here's the flange blank after cutting to its final shape.
It takes up a little space around the top, but, assuming I have multiple
pieces of lead to put in here, I should be able to install and remove them
quite easily. |
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Just for fun, I re-installed the BC door over the flange to
make sure everything still fit OK. Yes, it does. |
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Given that the BC door is made from the nose top layup,
only 2 ply BID, it 'oil-canned' a bit when I pressed on it. I didn't
want that to cause any issues down the road so I added a piece of 1/4" PVC
foam as a backer. This shot shows it being microed into place. |
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Then I added a single bly of BID over that foam and the
back of the BC door. If I have fit issues (door is too thick) I will
simply remove that one ply from around the edge where it overlaps the
flange. I don't need it for structural strength, it was simply added
to protect the foam. That single ply, and the foam underneath it, are
being vacuum-bagged in this photo. |
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Here's a shot of the flange after trimming to final shape
and cutting a slot in it to allow it to be flexed enough to install.
You can see some dots around the edge, I made these marks with pencil, after
removing that paper diagram that was spray glued onto this piece, to ensure
I correctly located the flange into the fuselage. |
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Now it was time to add glass to cover the exposed foam
inside the BC. I made this out of four pieces, overlapping on the
vertical corners, then peel plied it to keep the seams/overlaps smooth. Of
course, you will have to re-cut the slot for the flange after this layup,
since it goes all the way to the skin layer. This went quick, using
the Fein Sander tool just like the step
above. |
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I finished the flange install, by, after using a ziploc bag
and squirting some flox into the slot I cut above, re-inserting the flange
in the slot, adding some flox below it, and cleaning up the excess flox that
worked its way out. |
| That completes the Ballast Compartment for
now. |
