VELOCITY XL FG
N478B
LANDING GEAR / WHEELS / AXLES
Velocity’s Fast Build Fuselage option
includes installed main landing gear and
nose wheel strut, as well as main gear
axles and wheels.
Upgrades / Options:
■ Toe-Brake Pedal System
■ Heavy duty
FAST LINKS TO:
1. Nose Gear Strut
Installation (1)
We installed the nose gear strut assembly during the
Head Start Program at the factory. The original
nose gear strut assembly is shown here without the steel strap around the
strut. I changed this design as
described below and for the reasons expressed in # 19 of the Related Projects / Ideas section.
2. Nose Gear Strut
Modification (1) (2) (3)
(4) (5) (6)
(7)
(8)
After several landings, the
steel face in contact with the nose gear strut on the original rubber shock
bends inward compressing the rubber and diminishing its shock absorbing
properties (1). This creates a gap
between the rubber shock and the strut, while on the
air (unloaded). Upon lowering the nose
on landing, this gap closes and the strut hits hard against the deformed metal
face of the bumper with very little, if any, shock absorbing action. This results in a somewhat rough nose gear
drop and taxiing. In addition, some
pilots have experienced significant shimmy a few times with properly-torqued
nose gear washers that they have attributed, at least in part, to this
condition. The fix from the factory was to add an aluminum plate between the
rubber shock and the strut to eliminate the gap (2). While still building, I decided to replace
the original shock with a part that had no steel plate on the side of the strut
to avoid the problem (3). The whole process is detailed on the NOSE GEAR BUMPER MODIFICATION in
the Related Projects / Ideas page.
I placed a 3/16” aluminum spacer between the canard
bulkhead and the bumper’s steel plate (4). The holes in the replacement shock
were 3/8” so I used 3/8 x 16 bolts and nuts.
I opened the holes on the canard bulkhead located such that the actual
rubber on the bumper would start at the level of the captivator and installed
the replacement shock vertically (5). I
inserted a couple of wide area washers as shims between the bulkhead and the
spacer, on the top bolt, to ensure a flat support for the spacer against the
uneven surface of the canard bulkhead. I
also inserted a couple of wide area washers between the aluminum spacer and the
rubber shock on the bottom to increase compression and ensure that the strut be
tight in place against the captivator.
This gave me about 5/16” to 3/8” spacing at the bottom of the bumper. I had to place 140 lbs of weights on the nose
compartment to compress the rubber shock enough to allow installation of the
captivator back in place (6). Once
unloaded, the strut sat in place tight against the captivator (7). I may have to
adjust the level of compression after flying.
The use of washers on the bottom bolt, will give me the ability to
adjust the compression by adding or removing them, once I start taxiing and flying
(8).
3. Nose Gear
Seal (1)
I made a seal for the nose gear hole with flexible
plastic to restrict air entrance to the space in the nose and installed it in
place with stainless steel screws.
1. Main Gear Bolt
Bushings Installation (1)
(2) (3)
I installed the fore and
aft main gear bolt knurled bushings with structural epoxy (Aeropoxy) per the
manual.
2. Main Gear Bolt
Reinforcement Pads (1)
(2) (3) (4)
I made microglass pads for
the main gear bolt washers to seat flat against the surface. I removed the washers, sanded the pads,
placed a radius around them for transition and reinforced with TRIAX layups,
per the manual. I sanded them, after
curing, to prepare for the additional TRIAX reinforcements between the center
section spar, gear bulkheads and fuselage sides.
I used a metal squeegee to fill the main gear, always
trying to minimize sanding (1). Little
sanding seems to do the job, although I have yet to prime and place a light for
the truth to come out (2).
4. Main Gear
Fairings (1)
(2) (3)
These were trimmed to fit with a coarse sanding disk
in the air grinder and final sanding with 80 grit sanding paper.
1. Rudder /
Toe-Brake Pedals (1)
(2)
The Rudder/ Toe-Brake
Pedals were assembled and installed per the manual. I used pieces of water heater rubber hose on
the supports to increase grip (1). I cut them
in the back such that they can clear one end of the tube, by sliding it all the
way to the other side, before centering them in place (2).
.
I used polyethylene tubing
inside the keel as a conduit for the brake lines. The point of entry to the keel is behind the
pedal assembly and close to the canard bulkhead on the pilot’s side. The conduit ends before exiting the keel in
the back.
2. Main Gear
Conduit (1)
(2) (3) (4)
Both individual nylon
(Nylaflow) brake lines are then routed to the sides of the sump tank, where
they enter smaller conduits that take them out the fuselage and down the main
gear legs to the brake calipers. By doing
this, I attempt to protect the lines, avoid hydraulic pressure loss due to
excessive moving/flexing of lines and possible rattling. I used hot glue points to keep the conduit
attached to the main gear legs and glassed over them per the manual. To minimize heat transfer, I plan to cover
each brake line with Viton tubing and fiberglass sleeving between the conduit
exit and the caliper fitting.
Nylon (Nylaflow) tubing lines
were installed per the manual for the upgraded Toe-Brake Pedals system. I used Adel clamps and a piece of
polyethylene tubing to support the lines going between the pilot and copilot
sides (1). I made a couple
of bends on the cabin side of the lines that feed the brake fluid for better
flexibility upon actuating the rudder/brake pedals (2).
4. Toe-Brake Pedal
Bellcrank (1)
The bellcrank was installed
and the rods were bolted between the pedals and the bellcrank per the manual.
5. Brake Fluid
Reservoir (1)
I installed the brake fluid
reservoir in the copilot’s side of the canard bulkhead, in the nose
compartment, at the level recommended by the manual. The brake lines penetrate the canard bulkhead
through recycled rubber tops from expired lab specimen tubes that I used as
grommets and “T” at the base of the reservoir.
LINK TO
CONSTRUCTION IMAGES ON THE OFFICIAL VELOCITY WEBSITE
THIS SECTION
IS UPDATED REGULARLY.
PLEASE
REPORT ANY MALFUNCTION OR BROKEN LINKS TO:
Jorge A. Bujanda / 2004