Stevens Aero Model eHopper User manual

eHopper
By Stevens AeroModel
Span 33.5 inches | Length 21.5 inches | Wing Area 235 inches2| Flying Weight 4.5 - 5.5 oz.
Version 02/02//2010
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 1 of 36

Product Support
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 2 of 36
WARRANTY
Stevens AeroModel guarantees this kit to be free from defects in both material and workmanship at the
date of purchase. This warranty does not cover any component parts damaged by use or modification.
In no case shall Stevens AeroModel’s liability exceed the original cost of the purchased kit. Further,
Stevens AeroModel reserves the right to change or modify this warranty without notice.
LIABILITY RELEASE
In that Stevens AeroModel has no control over the final assembly or material used for final assembly,
no liability shall be assumed nor accepted for any damage resulting from the use by the user of the final
user-assembled product. By the act of using the user-assembled product, the user accepts all resulting
liability.
If the buyer is not prepared to accept the liability associated with the use of this product, the buyer is
advised to return this kit immediately in new and unused condition to the place of purchase.
THIS PRODUCT IS NOT INTENDED FOR CHILDREN 12 YEARS OF AGE OR YOUNGER
WARNING: This product may contain chemicals known to the State of California to cause cancer and
or birth defects or other reproductive harm.
PRODUCT SUPPORT
This product has been engineered to function properly and perform as advertised with the suggested
power system and supporting electronics as outlined within this product manual. Product support
cannot be provided nor can Stevens AeroModel assist in determining the suitability or use of
electronics, hardware, or power systems not explicitly recommended by Stevens AeroModel.
For product assembly support, replacement parts, hardware, and electronics to complete this model
please contact Stevens AeroModel on-line at www.stevensaero.com.
Stevens AeroModel
PO Box 15347 - Colorado Springs, CO 80935 - USA
719-387-4187 - www.stevensaero.com

Project Checklist
Kit Contents
Laser cut wood (6 Sheets - See inventory on following pages)
Photo illustrated instruction manual
Rolled computer drawn plan set
1 - 12 in. length of 0.025 in. dia. music wire
1 - 18 in. length of 1/32 in. dia. music wire
1 - 18 in. length of 0.045 in. dia. music wire
1 - 19-3/4 in. length of 1/16 in. dia. carbon rod
2 - 24 in. length of carbon fiber flat stock (0.034 x 0.121 in.)
2 - 19-3/4 in. length of 1.5 mm square carbon tube
Large Hardware Bag (4 x 6 in.)
1 - 1 in. Foam Wheel [DUB-100MW]
1 - 6 in. length of 1/16 in. heat-shrink tube
1 - 1 in. length of 3/32 in. heat-shrink tube
1 - 2 in. length of 1/8 in. dia. hardwood dowel
1 - 6 ft. length 0.012 Stainless Wire
2 - 1-1/2 in. Foam Wheel [DUB-150MW]
Small Hardware Bag (2 x 3 in.)
1 - 4-40 x 1 in. Nylon Bolt
1 - 4-40 Blind Nut
1 - Line Connector [SIGSH445]
1 - Laser Cut Basswood Elevator Joiner
2 - Micro II E/Z Links for 0.045 in. wire [DUB920 / BULK27805]
4 - Micro Control Horn (Single Post) [DUB848 / BULK26305]
6 - Micro E/Z Links for 0.032 in. wire [DUB849 / BULK26310]
6 - Mini Rubber Bands (Black)
12 - 1/16 in. x 1/4 in. Alum. Crimp Tubes
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 3 of 36
Required Building Supplies and Tools
1/2 oz. Medium CA Glue
1/2 oz. Thin CA Glue
CA glue accelerator (kicker)
Hobby Knife with ample supply of #11 blades
Sanding block with 400 and 600 grit paper
Heat Gun and Covering Iron
Soldering Iron & Solder
Small Needle Nose Pliers/Wire Cutter
Small Round Nose Jewelers Pliers
Small Forceps
Scissors
Electrical Wire Cutter/Stripper
Straight Edge Ruler
0.025, 1/32, 0.045, and 1/8 in. Drill Bits
2.5mm Allen Head Wrench
Razor Saw
Hot Glue Gun
3/4 in. Clear Tape
1 in. x 2 in. length sticky back velcro
3/4 in. wide clear tape
1 Roll AeroFILM or AeroLITE covering film
Suggested Building Supplies
CA glue de-bonder
Long sanding bar
Razor Plane
Low Tack Painters Masking Tape

Required Electronics (Available at StevensAero.com)
3 Channel radio and micro receiver. We suggest the Spektrum DX6i or DX7 Computer radio and
AR6400* “Puck”. However, a conventional receiver and two (2) JR S185 servos* may be used
instead of the Spektrum gear.
Brushed Power System (Recommended)*:
GWS IPS-S2 motor [GW/IPS-DX2BB-2XCS]
Castle Creations Pixie-7P ESC
GWS 7x6 Slow Fly Propellor
7.4V Hyperion 120mAh CX G3 LiPo
Brushless Power System*:
E-Flite Park 250 [EFLM1130]
Motor Mount Tube [EFLM1960]
Castle Creations thunderbird 6 ESC
GWS 7x3.5 Propellor
7.4V Hyperion 240mAh CX G3 LiPo
*Substituting electronics other than specified is not suggested.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 4 of 36

General Assembly Instructions
Thank you, for purchasing this Stevens AeroModel eHopper™. A design inspired by Bill Stevens’ full size
Weedhopper. This model has been developed and manufactured using state of the art CAD/CAM
systems and features a unique interlocking construction process that, when compared to traditional
methods found in other model aircraft kits, save countless hours of measuring, cutting, sanding, and
fitting. We are certain that you’ll find our kit to offer a truly exceptional build experience. As this kit is
recommended for the advanced model builder and intermediate “pilot”; we invite absolute beginners to
correspond with us, or to seek the help of another seasoned builder. At any time should one run across a
term or technique that is foreign please don’t hesitate to contact our staff with your questions.
READ THIS
Please READ and RE-READ these instructions along with any other included documentation prior to
starting your build and or contacting our staff for builder support.
Pre-sanding
Do not skip this step. Prior to removing any parts from the laser cut sheet wood use a sanding block
loaded with 250-400 grit paper and lightly sand the back side of each sheet of wood. This step removes
any residue produced as a result of the laser cutting process and, as we have found that most stock wood
sizes run several thousandths of an inch over sized, slightly reduces the thickness of each sheet.
Leave your pre-sanded parts in the sheet until required in the assembly process.
Protecting your worktable
Use the poly tube that this kit was shipped in as a non-stick barrier between your worktable and the
product assembly.
Bonding the assembly
As this product tabs, notches, and otherwise interlocks like a 3D puzzle we suggest that when fitting parts
you dry fit (use no glue) the parts together first. It’s advised to work 1-2 steps ahead in the instructions
using this dry-fit technique which allows ample opportunity to inspect the fit and location of assembled
components and realizes a benefit as each successive part contributes to pulling the entire assembly
square. Once you arrive at the end of a major assembly step(s) square your work on top of a flat building
table and revisit the dry fit joints with glue. Using the dry-fit process you’ll be able to recover from a minor
build mistake and will ultimately end up with a more square and true assembly.
Unless otherwise noted in the instructions, always use medium CA glue for bonding parts.
Never force the fit!
Remember this is a precision cut kit our machines cut to within 1 thousandth of an inch in accuracy. Yet
the wood stock supplied by the mill may vary in thickness by up to 20 thousandths. This variance in the
wood stock can cause some tabs/notches to fit very tight. Hey, dad always said it was easier to take
away material than add it back. With this in mind, should you find a joint or two to fit rather snug consider
lightly sanding a tight fitting tab rather than crushing and forcing your parts together. You’ll break fewer
parts in assembly and will end up with a more square and true assembly.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 6 of 36

Wing Construction
Laminate center ribs R0 together, using 1/8
in. drill bits to align ribs. Remove drills before
glue sets! Ensure that sides etched “INSIDE
are glued face to face. The etched notches
will form the hole for the wing mount bolt.
Laminate ribs R1 on each side of the R0
assembly, again using 1/8 in. drill bits to align.
 Start with left wing. Fit spar S1 to center
rib assembly. Ensure that spar seats
snug against R1. Tack glue with thin CA.
 With rib/spar assembly flat on the table, fit
leading edge W1 to R1 and spar S1.
Tack glue with medium CA.
 Fit rib R2 to leading edge and spar. Note
All ribs are stepped at the leading edge
producing a 1/8 in. notch above W1that
will receive the W4 leading edge doubler.
 Fit trailing edge W2 to ribs R1 and R2.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 7 of 36
Notch

Wing Construction Cont.
 Fit wing tip W3 to leading edge W1 and
trailing edge W2. Square wing on a flat
table and bond all joints with medium CA.
 Fit and bond ribs R3, R4 and R5 to wing
assembly.
 Fit rear spar S2 to ribs. Square wing on
table and bond. NOTE - tip of spar rests
ON TOP of wing tip.
 Fit Leading Edge W4 and bond to W1
and ribs. “Arrow” on leading edge
indicates position at wing center.
 Cut 1/8 in. carbon strip to length and
bond to trailing edge with medium CA.
Repeat preceding steps and assemble
right wing to center rib/left wing assembly.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 8 of 36

Wing Construction Cont.
Lightly sand wing frame, rounding leading
edge and tip. Taper top surface of rear spar
and leading edge smoothly into wing tip.
Open slots in R0 with a 1/8 in. drill to form
hole for wing mount bolt.
Install 4-40 blind nut through hole from the
top of the rib. Nut may be recessed slightly to
facilitate smooth covering. Secure blind nut
with thin CA around edges of flange.
Cover wing with a high quality, user friendly
covering film such as Stevens AeroModel
AeroFILM or AeroLITE.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 9 of 36

Tail Feathers
Assemble horizontal stabilizer and elevator
per plan. Use sanding instructions on plan
set to prepare surfaces for covering.
Cover horizontal stabilizer and elevator.
With low-tack masking tape, secure stabilizer
and elevator to table as shown. Leave
approximately 1/32 in. gap between surfaces.
Apply 3/4 in. clear tape over gap to form
elevator hinge.
Ensure there is adequate “down” travel. If
not, remove tape, increase gap between
surfaces slightly, and re-tape.
Open slot for the elevator control horn on the
lower side of the right elevator. Fit control
horn E6, ensuring that it is perpendicular to
elevator. Secure with thin and medium CA.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 10 of 36

Tail Feathers Cont.
Assemble rudder frame per plan. Do not
install ply hinges or horn at this time.
Follow instruction on plan set to lightly sand
rudder in preparation for covering. Do not
round off rudder horn mount area.
Cover rudder with AeroLITE or AeroFILM.
Open slots for hinges with hobby knife or
razor blade.
Fit ply hinge pieces R5 in slots. Do not glue
at this time.
Remove covering from control horn mount at
base of rudder.
Fit control horn R6 to rudder. Note that short
arm of horn is marked “R” and extends on the
right side of rudder. Ensure that control horn
is square and perpendicular to rudder. Tack
with thin CA.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 11 of 36

Tail Feathers Cont.
Slip a length of .025 wire through the holes in
control horn and ply hinge pieces.
Carefully align wire/hinge line with centerline
of rudder, and parallel with rudder leading
edge. Bond hinges and control horn to
rudder with medium CA. Remove wire.
Assemble vertical stabilizer per plan.
Lightly sand vertical sub-fin, rounding lower
edge. Leave upper edge and trailing edge
square.
Cover vertical stabilizer. Remove covering
from top edge of stabilizer to allow wood to
wood bond with fuselage.
Remove covering from hinge mount area at
base of stabilizer. Do not install hinge at
this time.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 12 of 36

Fuselage Construction
Main Fuselage Boom: On a flat work
surface, align ply F1a on top of balsa F1b.
Ensure that the etching on both parts faces
up. Bond with medium CA.
Align ply F1c on the other side of F1b. Bond
with medium CA.
Using guide slots in F1b, drill 1/8 in. hole for
wing mount.
Seal boom with at least 2 coats of Deft
lacquer or similar clear lacquer spray.
If desired, paint boom black at this time with
Design Master lacquer spray or Paint Marker.
 Left Strut Assembly: With etching on
hub F5 (L) facing DOWN, carefully fit
middle strut F3. Tack glue with thin CA.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 13 of 36

Fuselage Construction Cont.
 Fit rear strut F4 to hub, trapping F3. Tack
glue with thin CA.
 Fit forward strut F2 to hub, trapping F3.
Tack glue with thin CA.
Seal strut assembly with two coats of Deft.
DO NOT SKIP THIS STEP. If not sealed, the
ply struts may absorb moisture and warp.
Paint strut assembly black and repeat sealing
process.
Repeat previous steps to assemble
Right Strut Assembly, ensuring that you are
creating a mirror image of the Left Assembly.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 14 of 36

Fuselage Construction Cont.
Pilot’s Seat. Please read this entire topic before
beginning assembly of this part.
Choose the set of ply seat parts appropriate
to the radio gear you intend to use. The
deeper seat sides S1a/S2a will accommodate
JR S185 micro servos. The thinner sides S1b/
S2b are used with the Spektrum AR6400.
Instruction Given For JR S185 Micro Servos
Fit seat side S1a (S1b if building for
AR6400) to seat bottom S3. tack glue
with thin CA.
Fit the other side S1a to seat bottom. Tack
glue in place.
Fit seat front S2a (S2b if building for
AR6400) to assembly. Tack glue.
Gently pinch sides together and fit lower back
rest S4. Ensure etching faces forward. Tack
with thin CA.
Fit upper back rest S5 between sides,
ensuring etching faces forward, and tack in
place.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 15 of 36

Fuselage Construction Cont.
Pilot’s Seat Continued.
Round off front edges of balsa headrest S6.
Check alignment of seat. Gently twist
assembly or re-fit pieces as necessary. Bond
all joints with medium CA.
Fit seat struts F7 to side and front as shown.
Ensure struts are in the same plane as the
base of the seat. Bond with medium CA.
Seal seat assembly with two light coats of
Deft and paint desired color.
For Spektrum AR6400 receiver/servos:
Use instruction given for previous
assembly steps substituting seat side S1b
and seat front S2b. at steps with ★
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 16 of 36

Fuselage Construction Cont.
Nose Wheel / Strut Assembly: Laminate
two ply strut parts F6. Align carefully and
bond with medium CA.
Seal strut and paint black at this time. Leave
tabs unpainted, to provide a good wood to
wood bond with the fuselage boom.
Fit two ply sides F8b to ply wheel fork F8a
and tack with thin CA.
Fit fender front F8c to fork/side assembly.
Bond entire assembly with medium CA.
Seal strut/nose wheel assembly with two
coats of Deft and paint desired color.
Fit fender assembly to nose wheel strut. Align
carefully and bond with medium CA.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 17 of 36
Tabs Unpainted
Tabs Unpainted

Fuselage Construction Cont.
Fit left and right strut assemblies to slots in
main fuselage boom as shown. Tack with
medium CA glue.
Using a length of 0.045 in. wire, make a 90
degree bend 1/8 in. from one end. Cut wire
to length indicated on landing gear plan.
Do not bend other end at this point.
Cut two lengths of 1/16 in. heat shrink tubing
1-3/8 in. long to make axle spacers.
Install axle and seat in this order: Slide axle
through one wheel, then through left hub/strut
assembly.
Now, slide one spacer onto axle.
Next, slide seat onto axle. Ensure seat is
facing forward!
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 18 of 36

Fuselage Construction Cont.
Now, slide remaining spacer onto axle and
extend axle through the right hub.
Finally, slide remaining wheel onto axle and
make another 90 degree bend 1/8 in. from
end. Ensure bends at each end of the axle
are in the same direction.
Center axle in seat assembly. Bond axle to
hubs with medium CA. Ensure bends at axle
ends point down as indicated on landing gear
plan. Do not bond seat to axle at this time.
Shrink axle spacers using a fine tip soldering
iron in close proximity.
Fit nose wheel strut to F1 and seat struts.
Tack with thin CA glue.
Nose Wheel: Using a length of 0.045 wire,
make a 90 degree bend 1/8 in. from one end.
Trim wire to 3/4 in. length to form front axle.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 19 of 36

Fuselage Construction Cont.
Trap 1 in. wheel in fork assembly with wire
axle. Retain axle with a drop of medium CA.
Ensure that wheel is not bonded to axle.
Carefully check alignment of fuselage and
correct any errors. When satisfied, bond all
joints with medium CA.
Fit vertical stabilizer to slot on bottom of
fuselage boom. Ensure stabilizer is aligned
with the vertical centerline of fuselage and
bond with Medium CA.
Using a 0.025 drill, open hole for rudder hinge
in center of notch at end of boom.
Fit ply rigging tab F10 in slot in ply hinge F9.
Tack glue rudder hinge assembly to base of
vertical stabilizer.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 20 of 36

Fuselage Construction Cont.
Using 0.025 wire, make a 90 degree bend 1/8
in. from one end. Trim wire to 2-3/8 in. to
form rudder hinge pin.
Insert hinge pin through rudder hinge tabs
trapping boom. Pass wire through hinge tabs
at bottom of rudder and vertical stabilizer.
Align hinge pin with center line of vertical
stabilizer. Bond hinge tab at vertical fin with
medium CA.
Hinge pin may be left to float free, or may be
secure by CAREFULLY placing a drop of
medium CA at top. Ensure CA does not bind
in hinge fittings!
Open mount holes in bottom of horizontal
stabilizer with a hobby knife or razor blade.
Fit horizontal stabilizer to tabs on F1. Ensure
that stabilizer is horizontal and perpendicular
to rudder. Bond with medium CA.
eHopperTM © 2009 Stevens AeroModel all rights reserved. Page 21 of 36