 |
Nosewheel Doors |
|
 |
Like many other builders, I wasn't happy with the plans
nosewheel door setup. I checked out a few other builders' web sites,
namely James Redmond and Rick Maddy, and then made something similar but of
my own design. The basic premise is using that space, filled with
urethane foam in
Chapter 6, Install Bottom, that sits 'over' the nosewheel cutout.
This space would be where the hinges resided, and, given I expected to add
foam to the backs of the doors, I could make some aluminum parts so no hinge
bolts would be exposed on the outside. |
 |
Here's the bottom skin, after removing from the fuselage
and cleaning off the extra foam and micro, with foam backing pieces added, 2
ply of BID over that and vacuum applied. Behind the door blanks you
can see another piece, these are the parts that fit into that space between
the two fuselage bottoms. Those parts are made up of 1/4" PVC, 2 ply
of BID and some aluminum slugs. |
 |
Here's the nosewheel doors blank after glassing, trimming,
cutting slots for the aluminum pieces and test fitting them. The
aluminum pieces have holes drilled and tapped into them to allow them to be
bolted to the hinges in the plane. Note the elliptical spot at the one
end. That's for the nosewheel. This whole assembly is not within
my metal shop teacher's tolerance limits, +/- .0005, but, it sure feels like
it. The most critical tolerance is nosewheel retract angle, too much
and it tries to hit the rudder pedal pivots, not enough and the nosewheel
sticks out of the bottom of the plane and keeps the doors from closing
fully.
|
 |
I thought I could get away with a slightly simpler design
than I had seen, that is, one door instead of two. Turns out there's
not enough space under the plane for a door like this with the nosewheel
retracted - it will hit the ground before it opens far enough to let the
wheel out. No worries. I designed this with two doors in mind
anyway. |
 |
So, I went with two doors. I've used some hardware
store bolts to affix the aluminum pivot pieces to the doors themselves in
this shot. I also have a solder lug screwed onto one of the screws on
each side. I was testing different spring and/or bungee arrangements
to see what I liked. I need something that keeps the doors open when
the nose gear is down (you don't want it closing on the doors when they're
closed.... crunch....) but pulls them closed when the nose gear retracts.
Tim Andres has a nice idea I think I'll morph into something a little more
simple. |
 |
In this shot, you can see some fiberglass strips that have
been floxed onto the underside of the skin, between the hinges, to fill some
of that hinge space. They also help the doors match the curvature of
the fuselage when they close, otherwise, they stay a tad straighter and then
look too flat next to the curved fuselage. |
 |
A full-on shot looking aft. You can definitely see
the 'shelf' since the cutout for the wheel and box are smaller than the
cutout for the doors. You can also see the aluminum pivot pieces I
made. |
 |
This closeup of the mounting pieces shows how they work.
Two hinge pieces, one each fore and aft, machine screws holding the hinges
to the mounting pieces, which were microed into the fuselage bottom after
inserting aluminum slugs into fiberglass-covered PVC foam pieces. |
| That completes the nosewheel doors basic
construction. I still need to design and install a spring/bungee
arrangement to hold them open and pull them closed properly. |
