Building
The RagWing SPECIAL bi-plane is a lightly powered ship which has
been designed with the sensible intention of creating a moderately
fast bird which can be used for cross-country work. Inexpensive
to build, simple in its general design and structural details and
only simple tools are necessary for fabrication. It has certain
definite characteristics which will appeal to nostalgia builders
who grew up constructing old balsa and tissue rubber band models.
Perhaps the outstanding single characteristic of the RagWing Bipe
is the way it handles in the air. Flown by many different pilots
it proved to be easy to take off, simple to handle in the air and
even easier to land. A Veteran ultralight pilot with better than
1400 hours agree that in spite of its moderate horsepower and general
light weight, it behaves and is safe and easy to fly; that it will
land itself, and that it has no apparent vices.
Even a beginner can pull this ship off the ground with a run of
150 feet or less.( By beginner I mean a student pilot and not any
person with no training at all.) Once in the air, its extreme ease
of handling, stability and responsiveness to controls make it an
ideal ship for sport purposes. With a low landing speed of 32 to
35 mph, many of the difficulties presented by this operation are
automatically eliminated. With a cockpit 24 inches wide and the
ships low weight it is capable of lifting pilots with more weight
than its own and has room for men standing tall at 6'6". It also
features a one man 30 minute wing fold which allows sharing a hangar
or towing home.
Almost all aircraft builders ask for a sequence of construction
so I polled most RagWing builders to come up with the most recommended
sequence which follows:
It
is always good to study the plans thoroughly before beginning construction;
however, you will find that as you handle and dry fit parts together,
many of your unanswered questions will answer themselves. And as
always if help is needed its just a phone call away either to the
designer or the fellow RagWing Newsletter
members.
Step 1.
Begin
the rib construction with the assembly of a jig board. The rib drawing
is full size and will be placed on a piece of plywood or compressed
board and then blocked up to allow constructing all 34 ribs from
the same jib so that all will be identical Specifications and materials
are listed on a complete Bill of Material. It is essential that
the front spar rear spar and aileron verticals are exactly the same
because these members are used to align the wing during assembly.
Step 2.
The
tail feathers are constructed much like the ribs except that you
must draw the outline of the tail from the dims. given in the plans.
This is done because large blueprints cannot hold the tolerances
given because of shrinkage. Draw out the tail feather prints on
a flat table and cover with clear plastic. Carefully cut and dry
fit all members. Glue together and allow to dry Before removing
from table and jig blocks, fit and install all corner blocks and
gusset plates. Remove from table, flip over and install remainder
of gusset plates.
Step 3.
All
spars all built from 3/4 X 3/4 cap members with a 1/16 ply web glued
to the front side of the forward spars and the rear side of the
rear spars. A fence is nailed down to one edge of your work table
to build the spar against. Be sure to snap a chalk line so that
they will be perfectly straight. Cover the work area with plastic
and nail down enough small blocks to keep the caps in a straight
line. Fit and install all verticals. Take care to get a good fit
with no less than 80% contact between wood joints. Dry fit the web
material. When all parts are ready to assemble remove pieces, glue
and reassemble. Web material will be stapled in place while the
glue dries, then removed. Layout, drill holes and temporarily install
all spar fittings.
Step 4.
To
assemble the wing you first slide the ribs onto the rear spar and
align ribs with the verticals. Next block the front spar up against
the "fence" on your work table. Next slide the front of the ribs
up to , and aligned with, the verticals on the front spar. Now dry
fit all diagonals and compression members per prints. Be sure not
to install the diagonals backwords. Before beginning gluing be sure
that both spars are parallel and square. Glue all members in place
and allow to dry. Next remove wing away from fence and secure to
table with the front spar hanging over the edge of the table approx.
one inch. Install all nose ribs and allow to dry. Install the 1.5
mm plywood leading edge wrap by first gluing the ply to the top
of the spar and letting dry. Next wrap the ply and secure onto the
bottom spar cap. This can be performed by two people or one person
using strips of rubber inner tube and twine twisted on like a tourniquet
(Follow builders instructions supplied with plans package.) Allow
wing assemble to dry.
Step 5.
Install
aileron trailing edge and gusset plates. Install aileron spars and
allow to dry. When assembly is dry then drill and install the aileron
hinge brackets and hardware. Cut, fit and glue the "X" bracing between
each rib. Ai leron may now be cut loose- and removed from wing.
Install the aileron nose ribs and Install the leading edge wrap
the same as the wing leading edge. Remember to polyurethane the
inner surfaces of any wood and areas not accessible after ply wrap
is installed. Install wing tip bows and fabric stiffeners. Complete
all 4 wings. Upper wings will build much faster since no ailerons
are incorporated.
Step 6.
Draw out the
fuselage sides using the "fence" as a guide for the upper longerons. Again
cover with plastic so that your side will not be glued to the table. Fit and
install the 3/4 X 3/4 longerons, the diagonals, the vertical members and
blocks. to fuselage sides. Let dry then build another side directly
over the top of the first side. After drying remove and install
the 1/8" ply fuselage sides. Build one right and one left side.
(construct the fuselage spars per print. Start assembling sides
by first placing the sides up-side down on the table. Snap a chalk
line down the center of the table to be used for aligning. next
install the spars then the remainder of the horizontal 3/4 X 3/4
members. Cut and fit the 1/4 ply seat back/bulkhead and glue in
place. After this has dried then pull the tail section together
and secure by blocking and clamping. Install all horizontals and
diagonals and then the gusset plates. Take particular care to keep
the fuselage sides square and properly aligned. Complete the fuselage
by installing the 1/8 firewall ply and then the 1/8 ply bottom.
Front and rear turtledecks will be installed during step number
9.
Step 7.
While
fuselage is still upside down on table, construct and install the
landing gear. The gear was designed just like the remainder of the
aircraft in as that there is no welding or tube bending required.
Cut, drill, fit and bolt together the landing gear per prints. No
bungee was used on the first ultralight prototype but is a option
now offered and shown in the plans.
Step 8.
Assemble
stabilizer, elevator and ruder to fuselage per prints. Level the
top longerons fore and aft and side to side. Level stabilizer and
fin. Make and install tail brace cables. With assistance, install
wings to fuselage and adjust for proper dihedral and angle of incidence.
Because of the way that the upper wing root brackets are installed
the 2 upper wing panels are rigged as one wing. After wings are
completely installed then the upper wing root fittings can be separated
allowing the wingfold to be installed and used. Construct and install
wing "I" struts and flying and landing wires. Install and rig all
controls for proper movement of control surfaces.
Step 9.
Install
the engine, instruments, fuel tank, turtledeck, windshield, and
all remaining parts of the airplane per the plans and engine supplier
requirements. At this point you are considered 90% complete with
only 90% left to do. We recommend only aircraft engines like 2si,
Rotax 277, 447 and 503, Hirth 's F-23, 2703 and Mosler. 35 horse-power
engines with a V-belt reduction called a K-Drive is still considered
to be the best engine for the ultra-light version and the Rotax
503 for the experimental version. But many have been successful
with alternative engine like Kawasaki, 1/2 V.W., full 4 cyl. v w.
's and a 3 cyl.. Chevrolet Sprint engines but not enough testing
has been completed to elaborate at this time.
Step. 10,11, and
12.
With
a felt tip marker, mark the proper location of all metal parts and
remove them from the airframe. Engine, instruments etc. will be
protected and stored. Completely disassemble and lightly sand the
entire aircraft. Brush or spray 2 coats of polyurethane to protect
the wood. Fabric cover and paint the aircraft according to the system
you have chosen. I recommend Latex House paint because of its durability,
low cost and light weight Only 1 and 1/4 gallons are used on the
entire plane. It cost less than $200 of material including fabric
to cover one light aircraft. My schedual is to rip the fabric off
about every 5 years for complete inspection which I feel is very
important for longevity so the latex system of covering has worked
very well.
Flying
the Aircraft
The RagWing SPECIAL is a very responsive yet gentle airplane to
fly especially with the ultralight empty weight of 250 lbs.
| Note:
The ultralight weight can only be made
with a engine package weight of 78 pounds. |
With its short 18 foot span it can handle wind easily and gives
a quick roll rate. Taxing is very easy with a steerable tailwheel
and S turns are required for better visibility over the nose. You
may take off in a 3-point attitude or tail up. Normal ground run
is less than 150 feet and climb is approximately 750 feet per minute
using a 35 h.p. Kawasaki 440A, 2.9 ratio belt drove and a 72 X 30
prop. Engine weight is 78 pounds. Using this set-up requires a throttle
stop to limit the level speed to 63 mph. Without the stop cruising
speed is 74 mph. Stalls are straight forward and very docile at
28 mph with a pilot weight of 170 lbs Landings can be performed
easily at 35-38 mph with very little ground roll.
Recommendations
After you have completed the construction of your SPECIAL, had it
checked by your friendly fliers and a Airframe and Powerplant Mech.,
and are ready to fly it, here are a few suggestions. Do not set
a time to fly the aircraft. Do not invite any more help than necessary.
Test off of the largest grass runway available Get fully checked
out in a taildragger by a certified flight instructor. Take your
time and get very familiar taxing the airplane in a tail up attitude
until you can handle every situation When its time to fly, line
up straight at the end of the runway, advance speed slowly to the
point of liftoff. Gently feel out the controls then cut the throttle
back in time to make a safe, easy landing. I usually do this several
times to become comfortable with any new aircraft that I fly. Remember
to keep a close watch on the engine instruments for any signs Of
overheating, etc.
Take a break and you and your friends give the airplane a good ground
inspection. When all is well, take the SPECIAL up for a turn or
two aroun d the pattern staying within gliding distance of the runway.
(Approx 6 to 1 glide with the prop not turning.) I don't recommend
flying a new airplane any distance from the airport until I have
at least 40 hours and 200 landings and have stalled the aircraft.
power on and off (at altitude) several times. During all of this
time constant monitoring of the instruments and ground inspections
should be performed.
