Gap Seal & Parachute Door
Several people on the Kolb list have
wondered about how to put a softpack ballistic parachute into
a Kolb wing. Here is one way to do it, but if I had to do it from
scratch, I would make the gap seal in two pieces, a top and bottom,
because while this is OK, it is a bear to get back on when you
do maintanance and reassemble the airplane.
Inside the gap seal is one of the last
parachutes ever made by Second Chantz, but it is about the same
size and shape as soft pack parachutes currently sold by BRS.
Along the leading edge of the parachute door is a piano hinge
to allow the parachute door to swing up and open, the door itself
is .020 aluminum sheet. Overlapping the door along both sides
is a width of aluminum sheet, and at the very back are retainers
to hold the door down, which also attach to some underlying structure,
part of the gap seal itself.
If the parachute is fired, the black
cartridge in the middle goes up and begins to pull the parachute
out behind it. The retainers are not screwed down tight, they
allow the aluminum sheet to move, and the thin sheet can be easily
deformed from the middle upwards once the cartridge is gone. As
soon as the aluminum sheet deforms upwards, it starts to come
out from under the retainers along either side.
Here is a detail close up of how the
sheet fits under the retainers. The sheet has a long slit cut
into it where it fits under the angle retainer along the back
edge.
Another detail of the hinge and the
retainer. Behind the hinge is a strip of Naugahide glued to the
gap seal and the door to keep out any water, it extends the full
width of the gap seal. Also, before the gap seal is installed,
I lay a plastic garbage bag over the parachute container soft
pack, draping it down each side and duct taping it around the
bottom of the launch rocket.
I took a length of fuel line tubing
and split it to fit over the aluminum sheet and around the launcher,
it keeps the launcher from chafing and keeps the aluminum sheet
in place. It is snug, nothing can move.
If I had to do it all over again, I
would have made the gap seal in two parts, because trying to get
the underside to line up with it's attachment points, and simultaneously
get the top side to line up with it's attachment points is a pain.
I would make the underside half attach to the airframe so that
the wings could lay on it while they were being attached, sort
of like FSII wings lay on the windshield frame during assembly.
Then I would attach and secure the top half of the gap seal over
the wings and parachute, and attach it to the bottom half. So
consider this a functional solution that could stand some improvement.