Building the XF8B Kit, added January 6th, 2002
| Components weights before assembly: 1. Firewall, crutch, servo tray, HDPE motor mount support, screws 4.5 ounces 2. Front fuselage halves 2.0 ounces 3. Rear fuselage halves 3.5 ounces 4. Coroplast Rudder and Stabilizer 3.0 ounces 5. Four 1/8" X 60" glass rods (to be trimmed to 54") 4.0 ounces 6. 1/4" X 1-1/2 X 36" aileron 2.0 ounces 7. Two wing panels 7.0 ounces TOTAL 25 ounces |
NOTE: The Dow Plazamate 60 lbs
foam used in the Boeing kit is not a
stable material. There are small
changes in size after wire cutting.
Every attempt has been made to
assure the builder that the
components will fit true and the
plane will build straight. Attention
to detail on the part of the builder is
very important to assure the best
alignments and fits possible.
foam used in the Boeing kit is not a
stable material. There are small
changes in size after wire cutting.
Every attempt has been made to
assure the builder that the
components will fit true and the
plane will build straight. Attention
to detail on the part of the builder is
very important to assure the best
alignments and fits possible.
| Crutch, firewall, HDPE braces Marking for screws Screw holes countersunk Holding parts at 90 degrees in vice |
Construction begins with assembly of the firewall, crutch and HDPE mount supports. The parts are CNC cut for perfect
alignment. It is easy to rush this step because the parts fit so well - DON'T. Take your time to make sure that every thing is in
alignment before drilling, screwing and gluing (ryhmes don't it?).
Take the crutch and lay the HDPE triangular brace on it. Notice that the HDPE is slightly wider than the motor mount portion of
the crutch. The HDPE should line up on the inside edge of the crutch. Mark a reference line with your pen. Also mark
reference lines on the rear of the firewall (the part with the hole is the top where the fuel lines pass through). These lines
indicate where to drill the holes for the wood screws that bind the crutch, firewall and HDPE to each other.
After drilling the holes slightly smaller than #6, by 3/4" wood screws, counter sink the holes so that screw head will lay flush.
Next assemble the firewall onto the crutch. It is best to do this by clamping the assembly into a table vise that keeps
everything at 90 degrees alignment. Check it thoroughly with triangles and carpenters squares then glue with thick CA.
Shoot with kicker after 30 seconds then remove assembly and recheck alignment. If it is not straight break it apart and
re-glue.
Using the holes drilled previously in the crutch and firewll drill pilot holes into the HDPE triangles. Maker certain they are
square to both the crutch and firewall. You may notice when you insert the screws into the pilot holes that a slight upward
dimple or surface pucker appears around the pilot hole. Simply remove the screws and trim off this riser with your Xacto
knife so that the HDPE weges fit tightly against the wood.
alignment. It is easy to rush this step because the parts fit so well - DON'T. Take your time to make sure that every thing is in
alignment before drilling, screwing and gluing (ryhmes don't it?).
Take the crutch and lay the HDPE triangular brace on it. Notice that the HDPE is slightly wider than the motor mount portion of
the crutch. The HDPE should line up on the inside edge of the crutch. Mark a reference line with your pen. Also mark
reference lines on the rear of the firewall (the part with the hole is the top where the fuel lines pass through). These lines
indicate where to drill the holes for the wood screws that bind the crutch, firewall and HDPE to each other.
After drilling the holes slightly smaller than #6, by 3/4" wood screws, counter sink the holes so that screw head will lay flush.
Next assemble the firewall onto the crutch. It is best to do this by clamping the assembly into a table vise that keeps
everything at 90 degrees alignment. Check it thoroughly with triangles and carpenters squares then glue with thick CA.
Shoot with kicker after 30 seconds then remove assembly and recheck alignment. If it is not straight break it apart and
re-glue.
Using the holes drilled previously in the crutch and firewll drill pilot holes into the HDPE triangles. Maker certain they are
square to both the crutch and firewall. You may notice when you insert the screws into the pilot holes that a slight upward
dimple or surface pucker appears around the pilot hole. Simply remove the screws and trim off this riser with your Xacto
knife so that the HDPE weges fit tightly against the wood.
| Drilling for dowels Components ready to assemble Trail fitting components Trimming imperfections |
Before joining the front fuselage halves to the crutch drill the holes for the front and rear
wing hold down dowels. The front holes are drilled 1-1/2" back from the front of the foam.
Use a 1/4" drill in your drill press. The hole should be just above and right on the edge of
the slot for the glass rods, this gives the hold down dowel a strong surface to pull into.
Shown above are the components ready for assembly. You may use either 30 minute epoxy
or Elmer ProBond Polyurethane for this step. Trial fit the componets and if the crutch does
not fit correctly trim the foam for fit. The third photo above shows the rear of the front half
of the fuse. Where the crutch exits the rear it is not quite seated in the foam. This is
visible in the last photo where the crutch is pinching the foam. Use an Xacto blade to
remove any foam binding the proper fit of the crutch. Once you are satisfied with the fit put
glue on the seam of one half of the fuse and on the front of both fuselage halves where
they will contact the firewall. The final photo shows the components held in alignment while
drying with generous layers of masking tape. Before finishing this step make sure the
crutch is down all the way into the foam where it exits the rear fuselage halves as this will
key to the rear fuse halves. You may need to use tape to hold the crutch firmly in the fuse
at the rear of the front halves.
wing hold down dowels. The front holes are drilled 1-1/2" back from the front of the foam.
Use a 1/4" drill in your drill press. The hole should be just above and right on the edge of
the slot for the glass rods, this gives the hold down dowel a strong surface to pull into.
Shown above are the components ready for assembly. You may use either 30 minute epoxy
or Elmer ProBond Polyurethane for this step. Trial fit the componets and if the crutch does
not fit correctly trim the foam for fit. The third photo above shows the rear of the front half
of the fuse. Where the crutch exits the rear it is not quite seated in the foam. This is
visible in the last photo where the crutch is pinching the foam. Use an Xacto blade to
remove any foam binding the proper fit of the crutch. Once you are satisfied with the fit put
glue on the seam of one half of the fuse and on the front of both fuselage halves where
they will contact the firewall. The final photo shows the components held in alignment while
drying with generous layers of masking tape. Before finishing this step make sure the
crutch is down all the way into the foam where it exits the rear fuselage halves as this will
key to the rear fuse halves. You may need to use tape to hold the crutch firmly in the fuse
at the rear of the front halves.
| Unit assembled with ProBond and held in alignment with masking tape |