Zero
Thank you for purchasing the 2548 Zero combat model. This plane can be built very quickly. It
is tough, durable, and will survive a lot of combat. It is intended for 2548 Scale combat but also
makes a great sport flyer.
Manufacturer makes no warranty, implied or stated, as to the suitability of the model or
materials for any purpose. The user accepts all responsibility for the safe use and operation of
the model.
Items needed:
1. 2 inch wide Strapping tape or bi-directional strapping tape. Carbon Fiber TOW is also
good. For Carbon Fiber TOW contact:
Albert Perkins, 5680 Winnebago Rd. Pecatonica, IL 61063, 815-335-2489 e-mail:
Demo555@aol.com
2. A little CA or epoxy glue.
3. Pro-Bond Polyurethane glue also sold as Gorilla glue.
4. Spinner 1.75” for the Zero.
5. Radio, 3-4 servo's (any size) Mini-servo’s and small battery preferred.
6. 3 control horns
7. Pushrods, miscellaneous connectors
8. 6 ounce Sullivan (426) rectangle fuel tank is required.
9. .25 size motor
Wing assembly:
Lightly sand the wings smooth.
Sand down the trailing edge if needed to fit the trailing edge balsa. Glue the 2 halves together
using foam safe CA or epoxy. Make sure they are straight and you have the dihedral angle you
want! (Dihedral is precut) Now apply Probond to the spar slot. To spread the glue into the slot
a piece of 2-56 pushrod wire bent into a 90 degree angle works well. Mist the slot with a water
spray bottle to activate the glue and get it to foam up more so it will fill the spar slot. Then push
the rod into the slot with a screwdriver or appropriate tool. Wipe off any excess glue that squirts
out. Be sure you have a light even coat of glue on top of the rod so the slot gets completely
filled with glue after it foams up. If you keep an eye on it while it dries you can redistribute the
glue form areas where you have to much to areas where you don’t have enough. Let everything
dry overnight. Pin the rods down so the Pro-Bond doesn’t push them out of the grooves as it
foams up. Repeat the process with the leading edge rod. You can make the leading edge slot
deeper with a dremel tool and sink the rod deeper into the foam. This will protect the rod in a
midair a bit. Sand off any excess probond or fill any defects with light weight spackle. Glue on
the trailing edge stick with probond. Put hte small piece of included carbon fiber underneath the
trailing edge sticks across the junction to strengthen the junction. This will prevent the wing from
splitting at the TE in a crash. You can do the spars, leading edge and trailing edge in one step
and rubber band and pin everything in place while it dries. Apply the included 1/8th plywood to
the TE area to strengthen it. It must be flush with the trailing edge of the wing. It is also a good
idea to use a pop sickle stick(included) to reinforce the leading edge where the rubber bands will
be pulling on it as the foam tends top get crushed after a while. To make things look neater you
can sink the Popsicle stick and TE ply into the foam. Bevel and shape the ailerons and attach
with CA type hinges. The small Master airscrew wood plane works great for beveling and
shaping. Use foam safe CA or be very careful not to use too much glue as it may attach the
foam. You can also attach the aileron with bi-directional strapping tape and cover over the tape
with rip stop. A light coat of 3-M 77 spray glue makes the tape stick better to the foam. Another
light coat on top of the tape allows the fabric to stick to the tape better. You can also cover the
wing first and then attach the ailerons with bi-directional tape. Use a light spray of 3m-77 to make
it stick to the ripstop better . Seal the edges of the tape with water based polyurethane or paint
or CA. The new 3m-77 might attack foam if you use to much. Apply a very light coat from some
distance so the solvents evaporate before they hit the foam. Test on the wing shucks first! The
ailerons should just clear the fuselage and be free to move.
You can also let the ripstop or Icarex fabric be the hinge. Use a single bevel on the ailerons.
Attach the aileron pieces with a couple of small pieces of masking tape. Flip the aileron up so it
is flat on the top surface of the wing. Use a couple pieces of scrap balsa or whatever to raise the
aileron up off the wing surface about 1/16 to 1/8 of an inch. You need this gap to allow the hinge
line to be free enough. If you don’t have enough gap the hinge line will be very stiff and
unusable! Now cover the bottom of the wing with ripstop and continue around the TE and onto
the bottom side of the aileron. When dry flip the aileron down and apply the tops side covering
including the aileron. For added security you can sew a line down the hinge line to keep
everything in place although this is not absolutely required. To repair a loosened hinge line I
make a small cut in the fabric and inject thin foam safe CA. Rub it into the needed spots and
your hinge line will be repaired.
Wing tip shape is traced on the back side of the instructions or box if needed. Sand to shape.
Fuselage:
A. Join the front and rear halves of the fuselage with foam safe CA or epoxy. Make sure the
grooves for the fuselage fiberglass rods line up. Try to avoid getting glue into the slots for the
fiberglass rods. Place both pieces on a flat surface covered with wax paper to help get them
straight. After dry, Lay the rudder piece on a fuselage half and mark it’s position. The bottom of
the rudder should be at the bottom of the fuselage. There should be about 1” of the fuselage
behind the rudder Remove enough foam to make for a tight fit of the rudder into the fuselage
after you join the 2 halves. You need to cut the fuselage to make a place for the elevator. Use
the rudder to get an idea where it should be. There should be about 3/4 to 1” of foam behoind
the rudder. Mark the spot with a marker and make 2 vertical cuts into the fuselage down to the
upper fiberglass fuselage rod. Remove these 2 pieces of foam and save them for reinstallation
after the tail group is mounted. It’s a lot easier to do these steps before joining than after! You
should make sure your elevator slot is square to the firewall. Use 2 levels to make sure it is at
least close. You can use some shims if needed later. Glue the fiberglass rods into their slots
with probond. A bent over scrap of 2-56 wire works well to spread the glue through the slot.
Push the rods into place with a screwdriver.
Mist with water to make the probond foam up and fill the entire slot. The rods must butt up
against the firewall. Do not notch the firewall for the rods. Pin them in place while the glue dries.
Install the 1/8 plywood wing hold down reinforcements at the same time. Wet the wood so the
probond will foam up well and fill the voids and bond them to the fiberglass fuselage rods. On the
front one leave enough sticking out so you can sand the shape of the airfoil in with a small drum
sander on a dremel. These will be CNC cut soon! The back one should end up flush with the
wing saddle area. Use probond to glue the 2 halves together. Do not glue the small area behind
the tail group at this time! You need it open to get the tail group in place later. Rubber bands
work well to hold the halves in position while drying. When dry sand off any excess probond and
fill and defects. A great planes power planer works great to chew off the excess glue. Be careful
though as it will remove foam very quickly also. Trial fit the canopy and cowl and sand the
fuselage as needed and trim the canopy as needed to get a good fit. Put the wing in place and
mark the spots for the wing hold down dowels. Drill the hold down holes through the plywood
pieces in the fuselage. Be sure to keep them square to the fuselage and right over the leading
and trailing edge of the wing.
B. Prepare the firewall by installing blind nuts for the motor mount. The back side of the firewall
is tough to get to after installation so don’t forget this step before attaching the firewall! If you
strip one out or need to replace a blind nut a 4-40 pushrod works great. Put the pushrod
through the hole into the fuselage and screw on the blind nut. Use the rod to pull the blind nut
into position. Use a nut to tighten the blind nut into place. Trial fit the firewall and motor
assembly before drilling the motor mount holes. You may need to remove a bit of the fuselage
and firewall for the muffler to clear and you don’t want to have that end up in an area where the
structural fiberglass rods are. Usually the motor ends up being tilted with the muffler down about
45 degrees. You can also use a muffler extension to clear the fuselage. When completed put
the throttle pushrod into position and then the fuel tank into position. You should also drill holes
for the fuel lines and throttle pushrod to come through. Be sure the lines won’t get kinked. Use
some scrap balsa blocks or dense foam to keep the tank away from the firewall or your fuel lines
will get pinched or cut against the firewall. Make sure the muffler will clear the fuselage. It’s
not a bad idea to put the motor mount screws in place while you attach the firewall so you don’t
get them full of glue! Attach the firewall with probond. Be sure to put in the fuel tank and throttle
pushrod and fuel lines before attaching the firewall! Masking tape can be used to hold it in place
while drying. After dry sand off any excess firewall. A belt sander works great here. Wrap the
fuselage with strapping tape just behind the firewall and just in front of the wing saddle and just
behind the wing saddle. This is critical as it keeps the fiberglass rods from being able to bow
outward on an impact and exploding your plane!
2. Tail assembly:
A. Find the rudder and elevator pieces. Sand them with course sandpaper to make a nice
curve on the edges. To make the elevator hinge, remove one side of the box of the coroplast;
the other side serves as the hinge. Make the initial cut down the center of the box being careful
to only cut through one side. You do not want to cut it off completely. After you have the initial
cut down the center of the box fold the box open. This will expose the areas that need to be
trimmed. Carefully trim off the excess material. After you have it trimmed, flex the elevator up
and down with maximum deflection. This will loosen up the hinge a bit. Make an elevator joiner
from a piece of scrap 2-56 pushrod about 4” to 6” long. Bend it so there are 2 one inch pieces
perpendicular to the remaining 2 inch piece in the center. Position it on the elevator and push
the ends into the elevator. You will be going across the flutes of the coroplast. When in
position remove it and force a small Phillips head screwdriver into the holes to enlarge them a
bit. Squirt some probond into the hole and replace the joiner wire. Place the elevator on a flat
surface and put a little weight on it to keep it flat. Use a small scrap of balsa to keep the joiner
pushed into the elevator as far as possible. Let dry overnight. If you skip this step and there is
tension in the elevator from the joiner wire it will pull the elevator into a bend.
If you plan to paint the elevator and rudder wipe them down with acetone or alcohol to remove
any remaining mold release from the plastic. You can also scuff it up with sandpaper or steel
wool to help the paint adhere. This is much easier to do before you join the tail group!
B. Find the center of the elevator and mark a line from front to back. This line helps you to
position the rudder correctly. Mark the elevator and rudder where they contact each other and
the fuselage so you know where to apply probond Be sure the rudder and elevator are square to
each other. Before you attach the tail group to the fuselage permanently it is a good idea to
place the wing on the fuselage and verify that the tail group is square to the wing. Make
adjustments as needed before gluing in place!
Place the elevator into place and check the incidence with 2 levels. Put one on the elevator and
one on the firewall. Set them both at zero. If needed make adjustments to achieve the required
zero incidence. Trim off any excess rudder from the bottom side.
If you are going to cover the fuselage with ripstop fabric it is easier to do it before the tailfeathers
are glued into place. You can also cover the fuselage with bi-directional and or colored packing
tape or even fiberglass if you prefer. Just cover over the slots you made for the rudder and cut
them open after covering is complete.
When satisfied apply probond to the tail assembly in all the area’s it will contact the fuselage and
itself. Put the elevator in place and slide the rudder up onto it. Try to keep glue out of the
elevator hinge line! Use the levels again to verify the incidence and apply clamps or rubber
bands to hold everything in place until the probond dries.
Double check the elevator incidence before the glue dries! Be sure the tail group is square to
the wing!
Replace the pieces of foam you removed earlier with probond. You will need to remove the
thickness of the coroplast to make them fit. Pin them in place while the glue dries.
Wrap the fuselage with strapping tape or carbon fiber at the firewall and just in front of the wing
saddle and at the trailing edge of the wing. This is critical to restrain the fiberglass rods. They
are very strong but will tend to bow outwards on a frontal impact and explode the fuselage. You
can also use Kevlar or carbon fiber TOW here if you prefer.
Cover the wings with 1.5 or 2 oz fiberglass cloth or rip stop nylon. or just plain nylon fabric. Lay
the glass on the wing and then brush on water based polyurethane varnish. If using rip stop or
nylon fabric, paint on a coat of WBP and then lay on the ripstop that has been soaked in warm
water. Smooth out the wrinkles and apply more WPB. Brush or squeegee out the wrinkles and
air bubbles. To fill the weave of the glass cloth mix spackolite filler with water until it is paint like
consistency and paint it on. When dry sand nearly all of it off. Be careful not to sand holes into
the glass! Then paint with Latex house paint. Or you can cover with a low temp film covering
or glass with finishing resins if you prefer. Rip stop fabric is a very tight weave and no further
filling is required. The best WBP varnishes will say alcohol resistant on them. I use McCloskeys
Crystal Clear. You can also use Icarex (polycarbonate coated nylon or polyester) type ripstop
nylon which is a lighter (usually .5 oz) ripstop which is coated with polycarbonate plastic. It has a
texture somewhat like paper. To apply it spray the wing and the fabric piece with 3m-77. Let it
dry for several hours. Carefully apply the piece of fabric and then iron it down with your covering
iron much like applying monokote .
You can also cover the wing and fuselage with bi-directional strapping tape followed with colored
packing tape.
The planes can be covered with low temp iron on film or painted with latex house paints or any
other foam safe paints. Test the paint on scraps first if your not sure! Many paints will dissolve
foam!
I recommend two small servo’s mounted in the wing for the ailerons. You can join them with a Y
harness. You can use a single servo with a torque rod setup, or you can install a cable with a
single servo mounted flat in the center section.. The elevator and throttle servo are mounted
inside the fuselage in the wing cutout area Then you can shift the receiver and battery either in
front of or behind the servo’s to get the correct CG. Install servo rails across the fuselage of
hard balsa sticks. Attach the included fabric to the fuselage with thinned epoxy or foam safe CA
where the sticks contact the fuselage to strengthen. Mount the control horn on the elevator. Use
a long drill bit to make a hole to the inside of the fuselage following the required path of the
pushrod. It is a good idea to use a scrap of foam or balsa to support the pushrod somewhere in
the back half of the fuselage or it can bow from side to side or up and down and will not be as
effective as it should be! I like to use a cable type of pushrod for the throttle. This decreases the
number of stripped gears in the throttle servo!
Attach the cowl to the fuselage with some small screws going through the cowl into the firewall.
The cowl will extend over the fuselage for an inch or so. The cowl may be longer than required.
Trim as needed. Glue the canopy on with your favorite canopy adhesive. CA will work but you
can fog the canopy if your not careful.
Put the decals included into place after painting. You must seal the edges of the decals with thin
CA or thinned epoxy to keep them in place. You can iron down the decals with a covering iron
on low heat to make them stick better. Be careful as they will melt with to much heat.
Balance point is on the spars or up to 1/4 inch behind the spars. The furthest back CG point is
the most nose heavy and is more stable. It will be touchy at the most forward CG point but will
perform the best if you can handle it! Set the control throws at: ailerons .5 inch up and down
and elevator at .4 to .5 inch up and down. Adjust later to your liking.
Aileron position can affect the amount of elevator trim required. Set the ailerons neutral or just
slightly reflexed (up) If the plane requires a lot of up or down trim to fly level you can adjust the
aileron reflex to correct this a bit. If the plane requires a lot of up trim to fly level and - or is pitch
sensitive especially to down maneuvers raise both aileron a few turns on the clevis and try it
again. I believe the pitch sensitivity comes from the ailerons fighting the elevator to control
pitch. The ailerons act as elevators on the short coupled planes. If the plane is overly sensitive
to elevator inputs even with reduced throws then make the plane more nose heavy by shifting the
battery forward. Another clue can be collected by flying inverted. It should take a little forward
movement of the stick to fly level. If the plane climbs or flys level hands off when flying inverted
you probably need to raise the ailerons a bit. It should go down somewhat but not radically.
If you use a bladder type tank placed on the CG balance the plane on the nose heavy side as
the added weight of the fuel won’t be a factor.
Put in a little up trim, have a friend give it a strong underhanded toss into the wind, and have
some fun!
I can be contacted by email at Hattrick@direcway.com.
Hat Trick Enterprises 920-887-3225 evenings only Mike Fredricks
W8530 CTH S
Beaver Dam, WI 53916 My web site is www.hattrickrc.com
I also have a great streamer material available. It is 7/8 inch wide, comes in 300-foot rolls.
This material is low drag, cuts easily, but does not fray off much. Cost is $2.75 per roll plus
shipping. Also available in ready to use pre-rolled streamers.
I also have Bi-directional strapping tape available. It has filaments running in both
directions. It comes on a 50 meter roll and costs 12$ plus shipping.
Custom CNC foam cutting and CNC routing is available.