The same tools and techniques described above are also used
when creating any other required openings in the cowl. Always
start with a small roughly centered hole and work out as needed.
Continually trial-fit the cowl in place, noting any further opening
adjustments with a marker pen.
Remove the cowl, make the
opening a little larger as needed and re-fit the cowl. As shown, our
Edge cowl was modified to fit neatly over the F.P.E. 6.8 twin
cylinder engine that we used in our prototypes. Our rule of thumb
for openings in fiberglass cowls is to always make the required
openings about 1/8" to 3/16" oversize, eliminating any possibility
of engine parts touching the cowl.
Fuel Tank Assembly:
The fuel tank supplied with the Edge 540T ARF kit has an 800cc
(27.05 oz.) capacity and includes a gasoline-compatible fuel
stopper. If you wish, commercially available fuel tanks of larger
capacities may also be used. The fuel tank area within the Edge
540T fuselage has been purposely designed to accept commercial
Du-Bro fuel tanks up to and including the #691 40 oz. (1200cc)
tank. In fact, the fuselage tank compartment is large enough to
accept two of these tanks, side by side. This is good information
should you choose to install a smoke system and need to locate a
smoke fluid tank.
We mounted our tank in the fuselage on the left fuselage side, just
beneath and ahead of the fiberglass wing tube receptacle. We
used a simple two-line system with one fuel line to the carburetor
and the second fuel line used as a vent/overflow line.
We
interrupted the carburetor fuel line, ahead of the tank, with a "T"
fitting. The line from this "T" fitting was used to connect a Bisson
#29011 large Fuel Dot, for fueling and de-fueling purposes.
Another similar fueling hardware choice might be the J'Tec P/N
#F2G "EZ Fueler product (shown below). This gas-compatible fuel
dot system also works well and includes a large "T" fitting. These
ultra-simple and lightweight fueling systems have each worked
flawlessly in our Edge prototypes and are highly recommended.
As mentioned, we used and recommend Du-Bro #506 Large
Tygon fuel tubing for the tank and fuel line installation in this model.
f) Place the cowl back onto the fuselage and align it with the two
rear pieces of tape. Use a non-permanent marker pen to transfer
the marks on the tape to the rear edge of the cowl on both sides
of the fuselage. Remove the cowl. On the fuselage, use a ruler to
now measure the distance between one of the rear marks just
made, forward to the cross-hair mark on the forward piece of tape.
Note and save this measurement.
g) Place the cowl on a flat work surface, resting on its rear edge.
With a small triangle and a marker pen, make three 90
O
lines on
the cowl surface, at the mark locations just made. Use a ruler to
measure forward from the rear edge of the cowl and mark the
distance that you noted earlier in the last step.
Repeat this
procedure for each of the three lines on both sides of the cowl. You
should now have the accurate location marks on the cowl sides for
drilling the mounting holes. Place the cowl back onto the fuselage
and use masking tape to hold it firmly and accurately in to the
fuselage.
h) Use a 1/8" dia. (.125") bit to drill clearance holes for the M3
mounting bolts through the cowl and fuselage sides, at each of the
six mounting hole location marks on the cowl. Remove the cowl
from the fuselage and set it aside for now.
Use a 9/64" dia. (.140") bit to re-drill the six holes in the fuselage
sides. The M3 blind mounting nuts are now installed. Use a small
amount of 5-minute epoxy and apply it around the seating surface
of the blind nut. From the inside of the fuselage, install the blind
nut into one of the drilled holes, being careful to keep glue out of
the threads inside the nut.
Use one of the M3 bolts and a
screwdriver to draw the nut fully into its hole and wipe off any
excess glue with alcohol. Install the remaining blind nuts in the
same manner.
The cowl is now ready to mount to the fuselage with the six
M3 x 10mm PWA bolts. We suggest using small sections of fuel
tubing between the head of the bolts and the cowl to provide
cushioning.
Now that the cowl is accurately mounted to the
fuselage, it must now be relieved to accept the engine and muffler
system for your particular engine.
Fitting The Cowl:
The fiberglass cowl included with the Edge 540T ARF kit has been
factory painted and clear coated. It must be opened up in certain
specific areas to fit your particular engine and muffler system. It
also needs to be opened up at the bottom rear half-round surface
to provide good airflow over the engine. To do this, we used a
Dremel
®
Tool and a reinforced carbide cut-off wheel to first remove
most of the open section in this area. We then used a drum-
sanding bit to clean up the edges and make this opening neat in
appearance. We then final sanded the opened edge to make it as
smooth as possible. Important - Always wear a respirator mask
and use eye protection whenever you are grinding fiberglass.
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