Stevens Aero Model Build It! PuddleBug UM Manual

PuddleBug
Ultra Micro RC for Spektrum / ParkZone 2.4 systems
Wing Span: 17 3/4 inches | Wing Area: 71 square inches | Average Flying Weight: 1.2 ounces
Build Instructions - Version 1.12 (revised 04.23.2018)
!!
um

Build Instructions
!
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 2
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 use by the user. 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 at www.stevensaero.com.
Stevens AeroModel
26405 Judge Orr Rd., Colorado Springs, CO 80808 USA
719-387-4187 www.stevensaero.com

Build Instructions
PuddleBugTM UM - Kit Inventory
☐Laser-cut wood, 6 sheets (See Sheet Wood Inventory, page 5)
☐Illustrated Build Instructions
☐Plan Set, 2 sheets, 11 in. x 17 in.
Taped to back of wood brick:
☐2 Strut, wire, .015 in. x 12 in.
☐2 Pushrods, wire, .025 in. x 12 in.
Hardware Bag:
☐1 Part F10, 1/64 in. Plywood – Grill
☐1 Part F12, 1/32 in. Plywood – Motor Mount Deck
☐1 Shrink tubing, 1/16 in. diameter x 1 1/2 in. length [5012]
☐1 Aluminum tubing, 1/16 in. diameter x 3 in. length [*]
☐1 Trexler Balloon Wheel, size #02
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 3

Build Instructions
Suggested Items to Complete this Model
Many of the suggested items listed below are available at your local hobby shop. For your convenience,
Stevens AeroModel stocks all the power system components and most of the building supplies required
to complete this kit. If you have difficulties sourcing any of these items locally, please visit our website,
stevensaero.com to purchase the items necessary to complete your model.
Required Electronics
☐RC transmitter with at least 3 channels
☐Receiver/ESC/Servo brick (PKZ3352)
☐Motor/Gearbox (PKZ3624)
☐Propeller, 130mm x 70mm (EFL9051)
☐LiPo battery, 130 - 160 mAh 3.7V
Covering Film Requirements
While any high-quality covering film may be used to finish this model, superior results will be achieved by
using genuine AeroLITE brand covering film, available exclusively from Stevens AeroModel. The lower
working temperature and light weight of AeroLITE are especially desirable for this type of model.
AeroLITE is one-third the weight of typical model covering films, and will present a significant weight
savings when applied to this model.
☐1 - PatchPakTM Bright Red AeroLITE
Sealing Bare Wood
While not required, it is suggested that a high-quality clear lacquer be used to protect and seal any
unfinished wood. One single light coat of clear lacquer should be sufficient to protect the model from
moisture, without adding significantly to the model’s final flying weight.
Many parts of this model may be colored using a lacquer-based spray paint. Listed below are some of
the products we have used on our models. Please feel free to use whatever products you prefer.
☐DEFT clear lacquer-based sealant (available at most hardware stores)
☐Design Master Color Tool, lacquer-based spray paint (available at most arts and crafts stores)!
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 4
Required Building Supplies and Tools
☐CA glue, medium, 1/4 oz (PAAPT04)
☐CA glue, thin, 1/4 oz (PAAPT10)
☐CA glue applicator tips (PAAPT21)
☐CA glue accelerator (PAAPT15)
☐Hobby knife with supply of #11 blades
☐Sanding block with 120 and 240 grit paper
Building Supplies and Tools
☐Covering iron and heat gun
☐Needle nose pliers, small
☐Clear tape, 1/2 in. (DUB916)
☐Velcro for mounting battery (PKZ1039)
☐Masking tape (low-tack blue painters’ tape)
☐AeroLITETM covering film
Optional Building Supplies and Tools
☐Balsa filler (HCAR3401)
☐Modeling clay (ballast)
☐CA glue de-bonder (PAAPT16)
☐Required Building Supplies
☐
☐Clear lacquer-based sealant (DEFT)
☐Lacquer-based spray paint (Design
Master®)

Build Instructions
Sheet Wood Inventory (1 of 1)!
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 5

Build Instructions
Builder’s Notes
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 6

Build Instructions
General Assembly Instructions
Thank you for purchasing the PuddleBug UM from Stevens AeroModel.
This model has been developed and manufactured using state-of-the-art CAD/CAM systems. Our kits
feature a unique, interlocking construction process, that when compared to traditional building methods,
saves 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 novice model builder and pilot, we invite beginners who have
purchased this kit to seek the help of an experienced builder and pilot. If at any time during the assembly
of this kit, should you run across a term or technique that is foreign to you, please contact our staff with
your questions.
IMPORTANT!
Please READ and RE-READ these build instructions along with any other included documentation before
starting your build and/or contacting our staff for builder support.
Pre-Sanding
DO NOT SKIP THIS STEP. Before removing any parts from the laser-cut sheet wood, use a sanding
block loaded with 120 - 240 grit sandpaper and lightly sand the backside of each wood sheet. This step
removes any residue produced as a result of the laser cutting process. We have found that most stock
wood sizes run several thousandths of an inch oversized. This step also slightly reduces the thickness of
each sheet of wood. Leave all parts in the sheet wood until required for assembly.
Protecting Your Work Surface
Use the poly tube that this kit was shipped in as a nonstick barrier between your work surface and the
product assembly.
Bonding the Assembly
This product’s tabs and notches interlock like a 3D puzzle. We strongly suggest that when fitting parts,
you “dry fit” (use no glue) the parts together first. It is advised to work 1 - 2 steps ahead in the
instructions, using this dry-fit technique. This allows the opportunity to inspect the fit and location of
assembled components, and shows the benefits of our construction technique. As each successive part
is added, it contributes to pulling the entire assembly square. Once you arrive at the end of a major
assembly sequence, square your work on a flat work surface, and bond 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
square-and-true assembly.
Unless otherwise noted in the instructions, we find it easier to “tack glue” parts (temporarily bonding parts
in assemblies, using a small dot of glue). When using medium CA glue, apply with a fine-tip CA glue
applicator. Never bond painted or covered assemblies with thin CA, as it can destroy the finish of a
beautifully prepared model.
Never Force the Fit!
This is a precision laser-cut kit. Our lasers cut to within 5 thousandths of an inch in accuracy. Yet the
wood stock supplied to us by the mill may vary in thickness by up to 20 thousandths. This variance in the
wood stock can cause some tabs and notches to fit very tightly. With this in mind, consider lightly sanding
or lightly pinching a tight-fitting tab, rather than forcing the parts together. You will break fewer parts in
assembly, and end up with a square-and-true airframe.
Manual Updates
Please check our website for updates to these instructions before starting the build. To obtain downloads
and updates for this model aircraft kit, please visit the product page at stevensaero.com
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 7

Build Instructions
Wing Assembly
The wing assembly is built in three sections (right/center/left) that are later joined together to make one
single assembly. When working with symmetric parts, you must be careful not to inadvertently build two
right or left sides – you must build one right and one left. You’d be surprised at just how many
seasoned builders (like myself) have made (and continue to make) this mistake. To assist in preventing
this from happening on your build I offer the following advice:
The wing frame components are etched with a part number and alignment lines. When bonding the W2a
and W2b wing frame parts together make certain that the etched lines on the individual parts are
positioned to the same side. The etched side of the wing frame becomes the bottom of the wing panel.
When adding ribs to these assemblies always make certain you are working with the etched side (bottom)
up. This assembly manual only shows the construction of the right wing assembly – I suggest you should
build the left side mirrored and alongside the right as you proceed. Finally, glue sparingly using just
enough (a tiny drop) to hold a part in position. Once until you are certain you are on the right track you
can revisit the assembly with a bit more glue – it’s much easier to recover from an error when there’s less
glue in play on the parts.
1. Locate and join together over the plan sheet, parts W1a and W1b, to create the W1 wing
center section sheeting. Next, locate W2a and W2b and join together to create the W2
outer frame. Glue. Note: Join these parts together so that the etching on the frame is on
the same side.
2. Build a right and left wing panel. Begin building by laying the right and left wing frames flat
on top of your work table with the ‘etched’ side facing up. The side of the wing facing up will
become the bottom and the ribs are assembled to the wing frame inverted. Locate and
install rib R2 to the wing panel – aligning the forward tab on the rib at the forward notch on
the wing. Glue the rib at the tab and notch point, then forward to the leading edge.
3. Install ribs R3, R4, and R5. Install these first seated within the forward notch point cut along
the inside of the wing frame, then carefully aligning the leading edge of the ribs, between
the etched lines (on the wing frame) that run forward to the wing leading edge. Glue each
rib to the underside of the wing frame from the notch point to the leading edge.
4. Now invert the assembly so that the bottom of the wing ribs rest along your flat work
surface. Use masking tape (or have an assistant help) to hold the leading edge of the wing
frame flat against the work surface. Wrap the wing frame down to meet the wing ribs at the
trailing edge. Align the panel and wing ribs at the trailing edge so that the ribs fall within the
etched lines at the trailing edge. Glue the ribs along the trailing edge and any points of
contact with the wing frame. Tip: Work over the full size detail sheet to assist in getting
your rib alignment spot on!
5. Install the S2 and S3 balsa wing spars to the corresponding notched locations within the
W2 wing frame – position the spar to fit within the recesses at the tops of ribs R3 and R4.
Glue the spars.
6. Build the wing center section from W1, ribs R1, and plywood spar S1. Locate the ribs to the
spar using the notches. Begin at the trailing edge, align the notches within the W1 center
section sheeting with the tabs on ribs R1, wrap the sheeting forward to the leading edge,
over the ribs and glue.
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 8

Build Instructions
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 9
Step 1
Step 1 Cont.
Step 2
Step 3
Step 6 Cont.
Step 6
Step 5
Step 4
W1b
W1a
R2
Bottom View
W2
R2
S1
W1
Bottom View
W2b
W2a
Bottom View
leading edge
R3
R4
R5
Bottom View
S2
S3
W2
S1
R1
R1
R1
W2
leading edge
leading edge

Build Instructions
Wing Assembly (continued)
7. Check each wing panel for proper square and correct if necessary. Sight from the
wing tip or root, along the bottom of the wing and compare the flats along the bottom of the
ribs (the ribs taper up to the trailing edge so just compare the flat portion of the ribs forward
of the S1 spar). Straight wings will have each flat rib bottom parallel to the next. Warped
wings will show deviation from rib to rib. To correct a warped wing, mist the wing panel with
glass cleaner, then pin, weight, or tape the panel to a flat building surface. Allow the wing
panel to dry, once completely dry, the wing will assume the shape of the surface it has been
pinned to. Note: This sequence appears as step 8 on the original printed plans. I think it is
far easier to correct the wing square prior to joining the wing panels to the center section
and have moved this step up in the build order in this instruction set.
8. Join the completed right and left wing panels to the wing center section. Fit the S1 spar to
the notch in the bottom of ribs R2 and R3. Align the right and left wing panel root edges
flush with the right and left edge of the wing center section. Glue. Note: This was step 7.
9. Sand the wing lightly to prepare it for covering. If the model will see any outdoor use, or if
your local flying area is particularly hot and humid, seal the model using a clear lacquer or
polyurethane based spray. We suggest ‘DEFT’ brand ‘Clear Wood Finish’ or some other
non-water based sealant. Tip: Just a light misting of the sealer is all that is required to
cause water to bead up and roll off the model. Using too much sealer only serves to make
the final model heavy.
10. Use the covering guide on the plan sheet to cut the covering for your wing panel and apply
it according to the directions provided by your covering film manufacturer. We suggest our
AeroLITETM film or a high quality pre-stretched tissue.
Fuselage Assembly
1. Build the central crutch. Locate the fuselage central crutch parts F1, F2, and F3 then dry
fit (use no glue) these components together – in the arrangement illustrated on the plan.
2. Key the tabs, along the completed central crutch assembly, within the corresponding
locating notches of the right fuselage side then glue.
3. Fit the lower inside nose doubler F7. Locate the tab at the top of F7 within the notch
between F3 and the fuselage side, align the holes in F7 with the corresponding holes in the
fuselage side. Use the aluminum axle tube to assist with the alignment of F7 (but don’t glue
the tube in!) at fuselage side, then bond F7 to inside surface of fuselage as shown on plan.
Tip: Use a slow set glue here – thick CA or better yet, traditional wood glue would be best.
4. In the same manner as step 3 above, bond the F6 upper inside nose doubler to the inside
surface of right fuselage side as illustrated.
5. Key the radio tray former F4 to the right fuselage side using the tabs on F4 to locate the tray
within the notched locations on the right fuselage side.
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 10

Build Instructions
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 11
Step 9
Step 9 Cont.
Step 9 Cont.
Step 1
Step 5
Step 4
Step 3
Step 2
S1
R1
R1
F2
Bottom View
Bottom View
S1
Assembled Wing
F4
Bottom View
Top View
R1
R2
R3
R1
R2
R3
F1
F3
F2
F1
F3
F7
F3
Bottom View
F6
F1
F3

Build Instructions
Fuselage Assembly (continued)
6. Fit the left fuselage side over the assembly. Square the whole of the fuselage structure to a
flat work table. Complete the gluing of the fuselage parts – wicking CA glue (sparingly - it
really doesn’t take much!) at all points of contact.
7. Repeat process outlined in steps 3 and 4 above to install the opposite inside fuselage
doublers F7 and F6 within fuselage assembly. These parts are to be located against the left
side and within the forward fuselage cavity.
8. Install the top deck former F5 to the top of the fuselage assembly. Glue to retain.
9. Bond the flexible plywood grill, part F10, to the recess along the front of parts F7 and the
fuselage sides. Bond F10 just under the central former F3 then wrap the flexible grill down
towards the axles. F10 should fill the recess and finish flush with the fuselage sides.
10. Bond the plywood “fender” F11 to F10, within the notches at F10 – just above the wheel
opening as indicated on plan sheet.
11. Using a new and sharp #11 blade, complete the cutting of the notch that runs through
former F5 (see illustration). This will allow the later passage of the strut wires through the
fuselage sides. Tip: Increase the durability of the strut fitting area. Harden the balsa wood
slot that you just cut using thin CA glue.
12. Bond the plywood motor mounting plate F12 on top of F3 and between parts F6.
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 12

Build Instructions
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 13
Step 6
Step 7
Step 7 Cont.
Step 8
Step 12
Step 11
Step 10
Step 9
F5
Bottom View
F7
F6
F10
F12
F11
F5

Build Instructions
Fuselage Assembly (continued)
13. Install the upper forward fuselage sheeting F9. Begin with the edge of F9 that is opposite
the “U” shape cut-out – position this edge flat against leading edge of F5 and on top of F6.
Glue F9 where it contacts F5. Once the glue has cured, wrap F9 down along top edge of
the fuselage, landing along the recess between parts F6 and the fuselage sides. Tip:
Moisten the outside surface of F9, wrap the part into position and retain with masking tape
while it dries. Once dry, glue F9 permanently in place. Note: Some builders have stated
that they prefer to install F9 after step 22 (motor installation) favoring better access
to the motor and motor mounting area.
14. Locate two cross-grained parts F8 (F8a and F8b) to inside of parts F7 behind grill - see
“Wheel / Axle Detail”. Use the 1/16 in. aluminum tube axle as an alignment guide. Tack glue
parts F8 with a medium weight CA glue making certain not to glue the axle in place.
Remove the axle tube and more permanently glue F8 by wicking thin CA glue between the
parts.
15. Using a new and sharp #11 blade, carve and shape the inside surface of F8 to match the
radius and relief within the plywood grill area – allowing clearance for the tire installation.
16. Build the Horizontal Stabilizer over the plan from parts H1, H3, and H4 as illustrated.
Prepare the H2 Elevator and V2 Rudder for tape hinges – follow the sanding instructions as
given on the sheet 1 of 2 of the ‘Detail Sheet’.
17. Lightly sand the fuselage with 220 and 400 grit sand paper. Using a clear lacquer or
polyurethane based spray, apply a thin coat to seal the fuselage and tail surfaces. We
suggest ‘Deft’ brand ‘Clear Wood Finish’. Spray lacquer can get heavy - just lightly mist the
model – using only enough of the product to ensure that water will bead up rather than soak
into the wood.
18. Use the covering guide on the plan sheet to cut the covering for your Horizontal Stabilizer
and apply according to the directions provided by your covering film maker. We suggest
AeroLITETM covering film, available at StevensAero.com
Final Assembly
19. The completed H1 Horizontal Stabilizer assembly keys to the tabs on top of the tail end of
fuselage assembly. Square the Horizontal Stabilizer to fuselage sides and relative to the
wings (temporarily fit to the model for this step). Glue the stabilizer to retain.
20. Key the Vertical Stabilizer V1 to fuselage assembly, passing the tabbed portion of the
Vertical Stabilizer through the notches within the Horizontal Stabilizer. Square the Vertical
Stabilizer, making it perpendicular to the Horizontal Stabilizer. Glue to retain.
21. Install the V3 fins matching the tab and notch points along the underside of the H4 braces
within the Horizontal Stabilizer assembly. Square V3 so that they are perpendicular to the
Horizontal Stabilizer. Glue to retain.
22. Mount the motor. Trim and sand the original pin type mounting post off of the motor gear
box (PKZ3624) prior to installation. Install the gearbox through opening in F9 and glue to
ply motor mount doubler. Note: there is not much clearance for the motor to pass through
the opening but it will fit – slide it in tail end first, passing it vertically through the slot above
the motor mount, then rotate it flat on top of the motor mounting tray. Ensure that there is
no side thrust. Glue the gearbox in place using medium CA glue, white glue, or silicone
adhesive (the last two adhesive options allow quicker removal should you need to service a
tired motor).
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 14

Build Instructions
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 15
Step 13
Step 14
Step 15
Step 17
Step 22 Cont.
Step 22
Step 21
Steps 19 and 20
F9
F8 (x2)
Bottom View
V1
H1
Bottom View
H1
V3
V3
F9

Build Instructions
Final Assembly (continued)
23. Apply the tape hinges to both the Elevator and Rudder – joining these parts to the
Horizontal and Vertical Stabilizers with clear tape. Use the reference information on the
‘Detail Sheets’ 1 and 2 as a guide.
24. Install the micro receiver ‘brick’ positioned along the bottom of former F4. The servo gears
should face the front of the model and the antenna trails to the back. Use pieces of double
sided servo tape (DUB634) or a dab of silicone adhesive to retain the receiver.
25. Glue the rudder control horn to left side of rudder. Glue the elevator control horn to lower-
right side of elevator. Follow the guidance on the ‘Detail Sheet 2 of 2’ for creating and
installing the servo linkage.
26. Bend a length of 0.015 in. diameter wire over the plan set to create the wing and landing
gear strut. Use the the ‘Strut / Wing Detail’ template on the ‘Detail Sheet 2 of 2’ as a guide.
Note: We have provided a spare length of wire just in case you mess up your first attempt.
It is important to bend this part accurately so take your time.
27. Fit and glue one S2 plywood tab to inside of one rib R1 – straddling the S1 plywood spar.
Insert the completed strut wire through hole in S2. Next, slide the remaining S2 tab over
the strut wire and glue this tab inside the opposite rib R1 – again straddling the S2 spar.
28. Prepare the balloon wheel for mounting. Using a Trexler inflating pump (TRX-HP) or a
clean SIG glue syringe (SIGSH627), carefully fill your Trexler Balloon Wheel with air. Never
inflate the tire using your mouth! – moisture from your breath will permanently damage
the inflation tube (causing it to stick together). The maximum inflation diameter is 1 1/2 in. –
do not overfill tire as this will burst, bulge, or otherwise deform the balloon tire. With the tire
inflated, twist the inflation tube three times, then wrap the tube around hub once. Finish by
tucking the remaining tube neatly between the outside wall of the tire and the wooden hub.
Trexler Balloon Wheel care: Always store Trexler Balloon Wheels in a cool dry place.
Inflate the Balloon Wheel prior to flying and promptly deflate after your flying session has
ended. Avoid contact with strong solvents. Always inflate using an approved inflation
device (Trexler Pump or clean syringe).
29. Complete the axle by trimming the provided length of 1/16 in. aluminum tube to the final
length indicated on the ‘Wheel / Axle Detail’ of ‘Detail Sheet 2 of 2’. Place the tire in the
fuselage and pass the axle through the fuselage and wheel hub to retain. Do not glue the
axle in place as it will frequently be removed to allow servicing of the Trexler Wheel.
30. If necessary extend the battery lead from your receiver – we stock a 3 in. extension that is
plug and play with the ParkZone product S(AUMEXT/3). Route the battery lead through
opening in F5 and under slot in rib R1 of right wing.
31. Mount the wing by sliding tabs S2 into slots in F5, guiding the strut wire through slot in
fuselage sides. Slide the ends of the wire struts into ends of the axle tube to secure wing.
Locate a length of velcro under the right wing panel as illustrated to retain the battery.
32. Stack the round balsa parts “a” - “j” atop one another and glue to form the ‘scale’ engine
glow head. Paint the engine head and glue this to the opening in F9 above the motor.
33. Balance the PuddleBug UM model at ply wing spar S1. Mount the battery under the right
wing outboard of rib R1 – locate the battery fore and aft to achieve proper model balance.
That’s it, the model is complete – proceed to the ‘Model Setup’ and ‘Preflight’ sections.
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 16

Build Instructions
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 17
Steps 23-25
Steps 23-25 Cont.
Step 26
Step 27
Step 31 Cont.
Step 31
Step 29
V2
R1
Bottom View
Step 32
H2
S2
R1
S2
do not glue!
velcro
strut
strut
strut
axle
Trexler #2
Complete!

Build Instructions
Model Setup
DO NOT ATTEMPT FLIGHT IF THE WINGS ARE WARPED. Inspect the wings for any warps that may
have occurred when covering the model, or while the model was in storage. Remove all warps before
flight. Lack of aileron control on this model will make flying with a warped wing difficult.
Rudder - Center the rudder. Then, set the direction, rate of travel, and dampening (expo) of the control.
The rudder servo should be controlled by the aileron channel on your radio, as the rudder on this model
also controls the roll of the aircraft. The rudder should follow aileron stick travel, i.e., moving the aileron
stick to the right should move the rudder to the right.
Elevator - Center the elevator. Then, set the direction, rate of travel, and dampening (expo) of the
control. The elevator will be controlled by the elevator channel on your radio. Moving the elevator stick
back should move the elevator up. Moving the elevator stick forward should move the elevator down.
The PuddleBug UM was designed to be a very docile flyer but is capable of astonishingly sprightly
handling. Start with the minimum control travel listed below and work your way up. The use of dual rates
on your transmitter will allow you to quickly switch from docile trainer to nimble aerobat! With the push
rods connected, per the instructions in this manual, set the control throws as follows:
Preflight
It is recommended that you have an experienced pilot assist you with preflighting your new model.
Just like having someone proofread something you’ve written, having a second fresh set of eyes inspect
your final product is often helpful in avoiding disaster.
While not a thorough preflight check, listed below are some of the major items that you should consider
checking when developing your own preflight check list. Get in the habit of always preflighting your
models before every flight.
Weight and Balance -Check the balance of your model (C.G., center of gravity). For proper
performance, the model should balance using the points indicated on the plan set – copy these marks to
the completed model using a marker or trim tape. Use your right and left index fingers to suspend the
model from below, at the marked balance points. If the top of the fuselage and horizontal stabilizer
appears to hang level with the horizon, the model is properly balanced and ready to fly.
If the nose or tail of the model hang down, move the battery forward and backward to make subtle
changes, or add clay ballast to the nose or tail as required to obtain proper balance.
Check Weather - The first flight should be outdoors in zero wind conditions. The PuddleBug UM can fly
in winds up to 5 miles per hour.
Inspect the Airframe -Always check for warps and obvious signs of wear or damage. Do not fly a
warped or damaged model.
Inspect Control Surfaces - Always check control surfaces for center, proper direction of travel, rate of
throw, secure push rod connections, hinges, and receiver/servo mounting hardware.
Check Wing Attachment Points -Always make sure you inspect for damage and wear. Make sure that
the wing and wing struts, if applicable, are properly attached.
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 18
Rudder Travel
+/- 15 degrees (minimum)
+/- 30 degrees (maximum)
Elevator Travel
+/- 15 degrees (minimum)
+/- 25 degrees (maximum)

Build Instructions
Preflight (continued)
Inspect Battery -Always use a freshly-charged battery. Never begin a flight with a partially-charged
or damaged battery.
Clear Prop -Stay clear of the prop arc, when applying power to the model.
Range Check Radio -Follow the manufacturer’s instructions for performing a radio range check.
Check for Traffic -Proceed to the flight line (with your mentor/instructor, if you are a novice pilot) and
look for other traffic. If the runway is clear, and no one is in the pattern to land, loudly announce your
intentions to take off. Remember, all aircraft on the ground must yield the runway to those landing.
Go Flying - Point the model into the wind (if present) and steadily advance the throttle to full power.
Use rudder control to correct track while on the ground. Within several feet, the model should be
airborne. Fly the model to a comfortable “1 to 2 mistakes high altitude”, reduce throttle to stop the climb,
then trim the model for straight-and-level flight at a comfortable cruise speed. The PuddleBug UM
typically cruises at just over one-half throttle.
Setup for Landing - Clearly announce your intentions to land. Make all landings into the wind, using
rudder and elevator controls. Crosswind landings should be avoided until you are comfortable with the
model’s in-flight behavior.
Congratulations!
Once you’ve completed your first flights, you will have noticed that the Stevens AeroModel PuddleBug is
a very stable model airplane. When built straight, and trimmed for level flight, it should readily return to
“wings level” from any attitude. When flying, we never miss an opportunity to allow an onlooker to get a
little “stick-time”.
If your first flight was a bit more exciting than you would have liked, and you are having problems with
erratic flight performance, please inspect your airframe and equipment for damage, improper installation,
and/or twists and warps. Check to make sure that the model is properly balanced. Moving the C.G.
forward slightly can also improve flight performance. The most common mistake modelers make is to try
to fly with a warped or twisted wing. Please make certain that your wings are straight and true, before
you fly.
At Stevens AeroModel, we are committed to improving your building and flying experience. We are
constantly refining our processes, designs, and manuals to reflect customer feedback. You may
correspond with the Stevens AeroModel staff at:
email: [email protected]
Phone: [phone]
PuddleBugTM UM - Build Instructions © 2010 Stevens AeroModel, all rights reserved. Page 19