Chapter 13 - Nose & Nose
Gear
Start: 01/10/07
Finish: 02/25/09
Total Time: 102 Hours
With our boat (a.k.a. fuselage) now sporting an airfoil in the front, we move on
to building the nose cone, and installing the retractable nose gear. We were a
little late with ordering the nose gear retract actuator and some of the nose
cone hardware, so we're starting a little out of sequence with the work, while
we're waiting for all the parts. We decided to use the electric nose lift from
Jack Wilhelmson, as it is the most compact unit available, and the manual crank
system specified by the plans does not appeal to us.
We start this chapter by fabricating the NG30 bulkheads, which protrude forward
from the F22 bulkhead to the F0 bulkhead, and supports the nose gear and part of
the rudder pedal system. We must reinforce these bulkheads at the nose gear
pivot point MKNG6, as well as at the actuator attach points.
After applying a reinforcing layup to the MKNG6 pivot location we turn the
bulkheads over and glass what will become the inside surface. After this cures,
we clamp the two NG30s together and true the edges to each other. This is where
we discovered we had accidentally made two left sides instead of one right and
one left. After deciding that trying to remove enough glass from the incorrectly
made piece to repair it was going to take just as long as remaking it, we cut
another NG30 bulkhead from foam. This was on a Saturday morning and we very much
wanted to continue on with our work. In an effort to speed up the curing of the
newly made bulkhead we decided to try putting it in the oven. A couple of posts
on the builders forum suggested that post curing in an oven at 240 degrees for
about 40 minutes would yield a strong part. Unfortunately, with only one side of
the bulkhead glassed, the foam core warped as the layup cured. So after 2 hours
of building a new (correct this time) bulkhead, we had yet another scrap NG30.
We again cut another NG30 from foam and proceeded with the appropriate layups.
This time we let it cure at room temp. It's possible that a lower temp like
170-180 degrees might have worked without warping the foam, but we didn't want
to risk another setback. We will likely test the 170 degree curing process on
some scrap foam when time permits. It would be nice to be able to quickly cure
small parts instead of waiting overnight.
After waiting for the 3rd attempt at the right side NG30 to cure we laid up the
15 ply reinforcing hardpoints for the landing gear retract mechanism and floxed
on the MKNG6 birch and aluminum hardpoints. The layups over the entire outside
surface and hardpoints are then done. We then cut the NG31, NG32, F0 and F5
bulkheads, which also make up part of the nose cone support structure.
The last steps we could complete until we have the retract mechanism for the
nose gear were to glass the nose gear strut with a 2 ply bid torsional
reinforcing layup, and cut the foam that will make up the fuselage side between
F22 and the nose cone. We thought perhaps we had been able to scrounge up enough
work in chapter 13 to keep us busy until the nose retract arrived despite our
lateness in getting it ordered, but it seems we were more efficient than we
thought we were. We suspect the retract will be here in a couple days, so in the
mean time we're going to jump ahead to chapter 14 and begin building the jig for
the center section spar. We'll return to the nose gear tasks as soon as we have
the parts to continue.
When the nose lift arrived we proceeded to fit it to the NG30 bulkheads. The
MKNG6 pivot point was also fitted to the bulkheads, and the strut was floxed to
the MKNG6. The NG5 backing plate is then bolted and through and floxed to the
strut. The NG3 and NG4 lift attach brackets are then floxed onto the strut and
clamped until cured.
Next the NG30 bulkheads are assembled with the F0 and F5 bulkheads, and floxed
onto the fuselage. Then the NG31, and NG32 bulkheads which make up the very
front of the nose are floxed into place. The floor is then microed into place
and glassed. After cure the sides are also glassed and microed into place.
After the sides are cured, reinforcements are added to the canard lift tab area,
and the rudder pedal pivot blocks are installed and reinforced. The rudder
pedals are then installed. We've opted for the adjustable rudder pedals from
Dennis Oelmann. They are a very nice set, powder coated in white. The powder
coating does create a coupe issues as well though. Anywhere that a machined fit
takes place, the powder coating interferes. This means one must carefully sand
and polish the powder coating away at places such as the brake cylinder arms,
the CS13 bushing holes, and even where the left and right halves of the pedal
assemblies slide together. It's not a big deal, just had us a little confused at
first as to why things weren't fitting correctly.
After the pedals are mounted we install the master brake cylinders. There are
instructions in Newsletter #64 on how to install lay down brake cylinders, such
as the Matco cylinders we are using. However, a number of people have told us
that this procedure doesn't provide for very authoritative braking. We decided
to devise our own method by making brackets similar to the ones used to mount
the landing brake actuator to the the landing brake. Two aluminum L brackets
attached to a plywood hardpoint would comprise an assembly we could flox and
glass to the floor of the nose. We were concerned about having to stomp on the
brakes hard some time and having the flox break away between the L brackets and
the plywood hardpoint, so we also installed a flush mount 10-32 bolt through the
plywood hardpoint and into the aluminum bracket. In order to make certain that a
nut on the top side of this bolt wouldn't interfere with the brake cylinder, we
decided to tap the aluminum bracket instead of using a nut, allowing us to grind
the bolt flush with the top of the bracket. This worked very well. We test
fitted the bracket/hardpoint assembly to the floor to find a position that
allowed for maximum movement of the rudder pedals, without interfering with the
nose cone sides. The nose floor and NG30 bulkheads were sanded in the area where
the bracket would be installed, and the location marked. Then we floxed the
brackets to the nose floor, and laid up 3 inch wide, 2 ply BID tapes over the
top of the hardpoint/bracket assembly. This reinforcing layup overlapped onto
the nose floor, and NG30 bulkheads by about 2 inches. When cured, we had nice,
solid mounting brackets for our lay down master cylinders.
At this point we again find ourselves in need of parts. We opted to use the
Matco nose wheel (as our main gear and brakes are Matco, it made sense to use
their nose wheel as well), which requires a different sized axle spacer to fit
the Cozy IV nose wheel fork. CG Products (aka CozyGirrrls) are making these
spacers for us, and currently have our nose wheel for fitment. When we receive
the wheel and spacers from them we will be able to continue on with final
fitment and contour of the nose. For now we'll jump back to chapter 14 again to
keep us busy.
We determined that rather then use the plans location landing light, which is on
the belly of the plane, we would put landing lights in the nose. We followed the
idea from Marc Zeitlin to use 1/8" plexiglass to create lenses in the nose cone,
and mount automotive style driving lights to F0. The first set of driving lights
we purchased for this purpose appeared to be a nice projector style, with thick
lenses. What we didn't realize until opening them up and test powering them was
that the lenses were ion coated, producing a very dim, yellow beam. We use the
term 'beam' loosely though, as they were not very focused, and could barely
illuminate the garage wall 15 feet away. They seemed more like fog lights,
despite the package stating they were driving lights. We were very unhappy with
them and were not about to waste time installing them, so we did a little
shopping, and purchased 2 more sets of lights which we would compare side by
side to determine which set to use. One set was procured at WalMart for about
$37. They were made by Pilot, and listed as 4" round truck/SUV driving lights.
The other set we found at Checker Auto for about $42. Made by Blazer, these
lights were a smaller elliptical design, though the sales associate claimed to
have them on his vehicle and was very impressed with them. We hooked up both
sets of lights and turned off the overhead lights in the garage. Both were very
bright, white light, and clearly better suited for the job. The Blazer lights
were more focused, however and thus did a better job of illuminating a
particular spot. The Pilot lights, while still very bright, were not as focused,
and seemed to have a lot of light loss due to the scattered beam. We decided the
Blazer lights would be our choice, and began working on how to install them. We
decided to use the included brackets to mount them to F0, and to notch the NG31
bulkhead so that we would be able to access the mounting screws from the side to
remove them if we had to change a bulb, or light assemblies. We then fitted the
nose cone loosely with tape, and shining a light through the nose cone door,
were able to locate where the lights would need to have lenses installed on the
cone. We marked the nose cone, made a template from paper, and cut out slightly
oversized pieces of plexiglass. Next we heated the plexiglass in the oven for 10
minutes at 300 degrees, and using oven mitts, held it in place over the nose
cone, shaping it with pressure. This created two lenses we can install into the
nose cone to allow the light out. We then cut the openings we had marked on the
nosecone, beveled the edges of the clear lenses to a 45 degree angle, and
installed them into the nosecone with flox. We then painted the inside of the
nosecone satin black to reduce glare, and to avoid having our plane look like
Rudolph the white nosed reindeer when the landing lights are turned on.
Though still needing a nose wheel, we decided to proceed on as best we could
with fitting the nose gear retract mechanism. We'll have to hold off on
installing the wheel well, and may need to make a little adjustment to the limit
switches once the nose wheel is fitted, but getting the retract mechanism in
place will allow us to continue on with shaping the nose. We ran into a little
trouble when installing our nose gear strut and NG6 pivot bearing into the NG30
bulkheads. When we installed the sides, we apparently didn't carve enough foam
away from the inside surface, so there wasn't enough room between the NG30
bulkhead and the nose side to fit the long bolt through the NG6. We grabbed the
right angle die grinder and attached a cutting wheel to it, then carefully cut
away just enough of the inside glass and foam to allow clearance for the bolt.
This would then require repair later, though it was a very simple matter of
sanding the area smooth and re-glassing with overlap.
The Wilhelmson nose lift brackets ship with 2 of the holes undrilled so that you
can match drill to your install. In order to locate these holes properly, we
installed the strut and the nose lift (taking time to slot the strut cover at
this point as well), and actuated the lift through the full range. This allow us
to position the nose lift brackets correctly and use our existing holes in NG30
to locate the holes on the brackets. Once drilled we bolted the assembly
together, extending and retracting the nose gear strut automatically for the
first time.
Click here to the video of the nose gear
strut retracting.
We then cut the foam block from the top of the nose, and began shaping the
bottom and sides of the nose. At this point we realized that it would be a good
idea to paint the interior of the nose now, while it was still easy to access.
Once the top was in place we would have access to the interior of the nose only
through the nose access door and the foot wells at the rudder pedals. The plans
call for the use of Zolatone, which is a fleck stone style of paint used in
commercial building interiors. The fleck stone appearance didn't appeal to us,
as we'll be using leather, carbon fiber, and brushed aluminum in the interior
trim work. We still wanted to paint the interior as well though, being there
would be areas that are not trimmed out. In order to provide a durable finish we
selected an acrylic urethane single stage paint, with a flattening agent to
remove any gloss. To provide good adhesion we used an epoxy based primer, which
we reduced down and sprayed lightly so as to not add much weight. With the
interior of the nose painted, we reinstalled the rudder pedals, master brake
cylinders, brake fluid reservoirs, and nose lift.
We then shaped the exterior of the nose bottom and sides, then glassed the nose
bottom. The plans nose bumper is typically installed at this time as well, but
we're going to use a slightly different nose bumper which will be installed
after the nose is completely glassed. We also installed the static port at this
time. Our static port is slightly different than plans, which calls for
inserting some aluminum tubing into the fuselage side and drilling 3 small holes
in it from the outside. We wanted to install a more conventional static port.
With the bottom of the nose complete, we flip the fuselage right side up again,
and shape the nose top. There is a template created form the M10 drawing that
you can use to contour the top, but we found that the template was too short.
The plans indicate that the nose should be highest in the middle, so we drew a
centerline from left to right, then drew two lines parallel to it an inch fore
and aft. We used these lines as guides when using our 24" sanding block, and
carefully rounded the nose to a shape we thought looked correct. With the nose
shaped correctly, our next step was to layup 3 plies of bid for the nose door,
cover the top of the nose with box sealing tape, and lay the nose door layup on
the tape. This allows the door to cure to the correct shape of the nose, but is
again removable so we may add some additional layups and properly carve the foam
recess for it to sit flush on the nose.
Long Pause....
A very sad truth about homebuilt airplanes is that life seems to get in the way
of building. The list of excuses for the lack of serious progress over the last
few months is as long as it is pointless. What we can say is that the plane
never leaves our thoughts and discussions. Every day we aren't able to work on
it we at least spend some time complaining to each other about the lack of
'plane time'. It's taken a month or so to really get ourselves back on track, so
we'll start back in with the lights...
Having previously selected and installed our landing and taxi lights, there was
a little finishing touch that needed to be taken care of with them. The landing
lights on most of the planes I've flown are sub-optimal at best. When we turn on
our landing lights we want to actually SEE the runway. The automotive industry
has turned to H.I.D. Xenon lighting for it's superior brightness, reduced heat,
and reduced current draw. This seemed to us like technology that needed to make
it to general aviation sooner rather than later. We purchased a H3 HID retrofit
kit from an online retailer, though we were a little skeptical as to the quality
of the components we would receive. When the kit arrived however, it appeared to
be of good quality, and test runs indicated a rather impressive brightness from
the retrofit. We found a handy location for the ballasts and inverters, and
replaced the halogen bulbs with the new H.I.D. bulbs.
Installing the Pitot tube involved simply routing out a little foam and floxing
it into place. We had a little trouble getting the hole located in the nose
cone, but with a little trial and error, and a little repair after the fact all
is situated well with the nose cone now.
We find ourselves coming back to this chapter in down times from other chapters.
One of the small changes we're making is to install gear doors for the nose
wheel well. Wayne Hicks has a great write up on how to make these simple and
inexpensive.
We found we had to spend a little time playing with different spring lengths and
diameters before we arrived at a solution that created a pleasing closing
action, but the end result was a simple and effective nose gear door system.
Video of the door actuation can be seen here.
Before putting the nose cone on we wanted to get the wiring for the landing and
taxi lights situated. Being we're now in the process of doing that we realized
that we need to fabricate our nose bumper mounting brackets so that we'll be
ready to affix the nose cone when the wiring is complete. A couple of 15 ply bid
tape brackets will provide the mounting tabs to secure our metal and plastic
nose bumper.
Next we drilled the brackets, nose cone, and skid plate at once to ensure proper
alignment of the bolts. Then taped the skid plate for a pair of AN3 bolts. The
bolts reach from the top of the brackets, through the nose cone, through a flox
pad, and screw into the skid plate. Then the nose cone is bid taped to the nose
sides, thus FINALLY completing this chapter. Though on paper it took 2 years to
complete this chapter start to finish, the calendar time was purely due to the
fact that most of the work in this chapter was done as 'filler work' when we
were waiting for materials or parts to cure.
Upon final assembly at the hangar we discovered a small issue with the emergency
gear extension mechanism. We had chosen to have the rod exit the panel at the
top of the IP, in the middle of the switch rack. We held off on cutting the hole
for this until much later however (when we were installing instruments and
switches). Upon final assembly we discovered that with the rod installed at such
a sharp angle to reach the top of the IP, it was rubbing on the bottom of the
elevator torque tube. We stole an idea from Bob Bittner and installed a second
universal joint on the rod, just aft of the F22 bulkhead. This allows the rod to
clear the torque tube while exiting the panel at our desired location.
