Approach Engineering AH-1F Cobra Electric Guide

A H - 1 F C O B R A
E L E C T R I C
APPROACH EGIEERIG
www.ApproachEngineering.com

AH-1F COBRA—ELECTRIC PAGE # 2
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
1.0 Purpose
To establish a process that e sures co trol a d sta dardizatio i the ma ufacturi g of AH-1F Cobra for use with electric
mecha ics. AP102.
2.0 Tools Required
Note: (A) de otes tools required for assembly a d
(T) de otes tools required for testi g.
Basic Ha d Tools (A, T)
Sa di g block a d paper (A)
Dremel Tool (A)
Epoxy 30 Mi ute (A)
Cya oacratulate (CA) (A)
.0 Reference Documents
Exploded View Pla s for AH-1F Cobra AP102. (A, T)
4.0 Attachments
5.0 Introduction
1. WARIG This aircraft is ot a toy. It is capable of serious bodily harm a d property damage. Every precautio
must be take to properly build this kit a d i stall all radio compo e ts. It is your respo sibility alo e to e sure all
safety steps are take outli ed i the Academy of Model Aero autics safety codes. If this is your first time buildi g a
aircraft kit it is highly recomme ded that you fi d experie ced help for the first flights. Co sult your local hobby shop
or write to the AMA for further guida ce.
Academy of Model Aero autics
5151E. Memorial Drive
Mu cie, IN 47302 [phone]
2. Please i spect all parts before buildi g. If a y parts are broke or missi g please feel free to call or write for replace-
me t. All i structio ma ual photos are i cluded with the CD alo g with other scale docume tatio pictures to ease i
fi ishi g. If a step or photo appears u clear to you i spect the CD for additio al photos with differe t views to aid i
assembly If you have a y questio s, comme ts, or improveme ts please call or write to:
Approach E gi eeri g
Ridgecrest, Ca. 93555
www.approache gi eeri g.com
3. We as the kit ma ufacturer ca provide you with assista ce a d a top quality kit a d i structio ma ual. Whe built
light, straight, a d true you will have a model that flies as well as it looks o the grou d. However the fi ished product
depe ds o the quality built i to it. We ca ot guara tee the flight performa ce. Take your time a d read all i struc-
tio s carefully before a d duri g co structio .
4. Duri g the assembly procedure the use of the term CA refers to thi CA glue a d CA+ refers to medium viscosity glue.

AH-1F COBRA—ELECTRIC PAGE # 3
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6.1 Pu ch out the four 3/32” fuselage side pieces for each side.
Assemble the side frames, (S-1, S-2, S-3, S-4) over a piece of
wax paper. The provided tabs allow for proper alig me t a d
assembly of the fuselage sides. Build a right a d a left taki g
ote of the tria gle stock refere ce li es a d have them faci g
up. These will aid i the i stillatio of the tria gle stock. Usi g
the otches provided assemble a d glue with CA the two fuse-
lage sides.
6.2 Place the completed assemblies of the fuselage side frames
a d lay them out to build a right a d left half. Have the tria gle
refere ce li es up so that they will be o the i side of the as-
sembly. Alig the fuselage doublers, FD-2, a d FD-3 by match-
i g the fro t otch edge (A), the ca opy top edge (B), a d the
bottom of the wi g otch (C) with the fuselage side. The
otches i the fuselage for F-3 a d F-4 will li e up with the
otches i the fuselage doublers. Usi g 30 mi ute epoxy glue
o the fuselage doublers. Set aside a d allow to dry.
6. Usi g laser pri ted tria gle stock refere ce li es, Glue ¾”
tria gle stock (TRI-2) alo g the bottom edge of both i er sur-
faces of the fuselage side betwee F-4 a d the tail boom e d
filler. Glue ¾” tria gle stock (TRI-3) alo g the upper edge of
the fuselage sides. Glue the 3/32” horizo tal fi doublers
(HFD) to the i side surface of the fuselage sides.
6.4 Glue F-3, with the text a d curved edge faci g up, a d F-4
i to the otches of the fuselage doublers to make the fuselage
box. Usi g epoxy glue i the two mecha ics mou ts i to the
otches of the fuselage doublers. Epoxy the formers a d
mou ts i to the other side of the fuselage.
6.5 Temporarily positio your mecha ics a d mark mou ti g
poi ts o the mecha ics mou ts.
6.6 Drill holes i the mecha ics mou ts o the marked posi-
tio s with a 9/64” drill bit. Press i the four 4-40 bli d uts o
the bottom side of the mecha ics mou ts. Logo mecha ics
mou t directly to the base which is assembled later. You will
wa t to fit the mecha ics a d properly place the mai shaft ce -
tered i the hole i the doghouse.
6.0 FUSELAGE ASSEMBLY
A
B C
FD-2 FD-3
Match a gle o
e d of tri stock.
HFD
Note: Logo mecha ics do ot
use the rails. Check fit prior to
assembly.

AH-1F COBRA—ELECTRIC PAGE # 4
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6.7 Tur the fuselage over a d epoxy the 1/4” light ply fuse-
lage bottom to the i side of the fuselage sides. Pu ch out the
1/4” chi block, CB, a d glue to the fro t of the plywood fuse-
lage bottom.
6.9 Worki g at the ose of the fuselage sides cut 3/4” tria gle
stock (TRI-1) to match the bottom fro t edge to F-3 o each
fuselage side. The e ds of the tria gle stock should mate up
flush with F-3 a d should exte d past the fro t fuselage side
edge to be sa ded off later. Cut parallel cuts to approximately
1/8” of the back surface to aid i the fuselage ose i be di g
6.11 Apply water to the fuselage side ose a d the tria gle
stock to aid i be di g. Usi g maski g tape be d the sides to
glue F-1 i place.
6.8 Tur the fuselage assembly over a d glue the four 1/2” by
1.5” square hardwood la di g gear blocks usi g epoxy. Try ot
to fill the 5/16” holes with epoxy o the e d of the la di g gear
blocks.
6.10 Glue the ¾” tria gle stock to the bottom edge of the ose
to F-3.
6.12 Glue F-2 alo g the ca opy side matchi g up the upper
edge.
6.0 FUSELAGE ASSEMBLY
La di g Gear Blocks
Match upper edge
CB
PLY
BASE

AH-1F COBRA—ELECTRIC PAGE # 5
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6.1 Pu ch out the two 1/8” light ply vertical fi supports a d
two tail rotor tube supports (TSR). The rou ded edge of the tail
rotor tube support faces foreword. Glue the two TSR supports
i the mid a d lower slots o o e side o ly.
6.15 Assemble each pulley idler assembly by first pushi g the
1/8” shaft through the beari gs. Place o e bushi g o each side
so that the e d of the shaft is flush with both sides. Complete for
both idlers.
6.17 Pu ch out the 1/8” ply tail rotor frame base (TFB).
Note: the base has a break out tab that will be removed later at
the fro t of the part. Do ot cut at this time. Slide the vertical
fi supports i to the base a d glue with CA+.
6.14 Assemble the two belt idlers pulleys as show . The
chamfered edge of the pulleys should face i ward to help guide
the belt.
6.16 Place the toothed idler assembly i the lower hole a d the
smooth idler i the upper hole. Take the supplied belt, ot the
o e with your mecha ics, a d place it betwee your idlers so
that the teeth are faci g toward the toothed idler. Glue the other
vertical fi support to the tube supports. You may place a small
amou t of glue o the outside of the bushi gs to help hold them
i place.
6.18 Glue o the 1/8” ply side pulley doublers (SPD) to the
outside of each pulley assembly by alig i g the edges.
6.0 FUSELAGE ASSEMBLY
Beari gs 2 each
Guide Washers 2 each
Note directio of teeth
Smooth Idler
Tooth Idler
Beari gs
TSR

AH-1F COBRA—ELECTRIC PAGE # 6
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6.19 Cut out the 1/8” ply traili g edge former (TE-2) a d glue
it i to the otches provided o the top of the vertical fi assem-
bly.
6.21 Cut out three tail rotor tube leadi g edge supports (TSF)
from the 1/8” ply. Usi g 30 mi ute epoxy glue to the vertical
fi supports a d the tail rotor tube.
6.2 Attach the 4-40 threaded shaft a d li k to the bell cra k
for the vertical portio . Attach a other li k to the lower bell
cra k arm.
6.20 Pull out the larger diameter, lo ger, tail rotor tube with
the four vertical cuts i o e e d. Usi g 30 mi ute epoxy glue to
the vertical frame so that the bottom edge is flush with the bot-
tom surface of the bottom tail rotor tube support a d the vertical
cuts are at the top of the fi assembly..
6.22 Slide the 1/8” bell cra k shaft through the hole o the
sides of the vertical fi support a d hold i place with a drop of
CA o the outside e d of the shaft.
6.24 Glue the completed assembly i to the otches provided
i the fuselage side.
6.0 FUSELAGE ASSEMBLY
Bottom edges li e up.
TSF
Li k to tail rotor servo. The
pushrod will be co ected
later.
Vertical pushrod
a d li k.

AH-1F COBRA—ELECTRIC PAGE # 7
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6.25 Make two sets of filler blocks by glui g o e filler block
side, FBS a d o e FBM to build a right a d left. Make a vertical
mark from the cor er of the FBM as a sa di g refere ce. The
face will be sa ded to that mark a d tapered to about 1/16” at
the tip.
6.27 Usi g your desired pushrod co ect it to the bell cra k at
this time. The outer housi g will be i stalled later. Usi g 1/4”
tria gle stock fill the gap betwee the FBM a d the tria gle
stock o both sides.
6.29 Sa d the horizo tal fi to the desired shape. Note: the
real aircraft has a flat top a d a rou ded lower surface. This
will pull the ose up i foreword flight a d is recomme ded to
sa d them to a symmetrical profile. Glue the ¼” x ¼” x 1-3/4”
balsa sticks i to the otches. These will go i to the fuselage
side a d doublers for i creased stre gth.
6.26 Worki g at the lower rear of the tail boom, trial fit the
filler blocks to e sure a good fit. Whe satisfied glue the filler
blocks i to positio .
6.28 Maki g two sets glue the upper a d lower horizo tal fi s
together, from the ¼” balsa, maki g sure to make a right a d a
left.
6. 0 Usi g 3/32” balsa cross sheet the bottom of the fuselage
starti g from behi d the fuselage floor to the e d of the tail
boom.
6.0 FUSELAGE ASSEMBLY
HF-B
HF-B
HF-T
Sa di g Mark
Co trol Rod
Co ector
1/4” Tri Stock

AH-1F COBRA—ELECTRIC PAGE # 8
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
6. 1 Usi g 3/32” balsa cross sheet the upper a d lower sur-
faces of the ose.
6. Remove the ce ter sectio of the vertical fi base to al-
low free moveme t of the belt drive. Also test fit the horizo tal
fi s for a proper fit. Do ot Glue the ¼” x ¼” x 1-3/4” balsa
sticks i to the otches. These will go i to the fuselage side a d
doublers for i creased stre gth.
6. 5 Pu ch out the 1/4” balsa tail rotor pushrod supports,
DDS-1 a d DDS-2, a d glue them o the bottom sheeti g sur-
face. Make sure that they are properly alig ed a d provide a
straight support for the pushrod. Whe satisfied glue the push-
rod outer tube to the supports with thick CA.
6. 2 Pu ch out the 1/8” ply ca opy backi g plate, CBT, a d
tra smissio backi g teeth, TBT. Matchi g up the profiles glue
them to the back of the fuselage doublers. This is to hold the
ca opy a d tra smissio guide teeth flush for a good fit.
6. 4 Slide the fro t pushrod tube support (DSS-3) up so that it
is supporti g the tube. The support should li e up with the tri-
a gle stock, sides, a d balsa cross sheeti g floor. Put the push-
rod tube through the hole that fits your desired servo layout.
Whe satisfied with the fit glue i place with CA+. Depe di g
o your radio arra geme t you may wa t to i stall a receiver
a te a wire tube ow for ease of i stillatio .
6. 6 Glue i the 3/8 tria gle stock alo g the balsa floor as
show . This will aid i sa di g a rou ded cor er. Apply tria -
gle stock to both sides.
6.0 FUSELAGE ASSEMBLY
DDS-1
DDS-2
1 1/2” lo g
6 1/4 Lo g
5 3/8” Lo g

AH-1F COBRA—ELECTRIC PAGE # 9
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
7.1 Sa d the face of the fuselage assembly flush with F-1.
Glue o the two 1/4” balsa TSU back plates (TSU-B) together.
Positio the otch toward the bottom of the fuselage a d glue
flush with the bottom a d sides of the fuselage ose.
7. Sa d rou ded cor ers o the three outside edges of the
TSU back plate.
7.5 Glue the TSU bottom pieces i to the otch i the TSU
back plate.
7.2 To aid i sa di g draw li es o the lower surface a d the
fuselage side ¾” from the sheeti g. Whe sa di g make a eve
tra sitio from li e to li e. Sa d the fuselage cor ers to their
fi ished rou ded shape.
7.4 Glue the two TSU bottom pieces, TSU-L, together. Mark
a li e 1/2” from the back edge as a sa di g guide. Sa d the
TSU bottom pieces from the li e at a co sta t a gle to about
3/32” up from the rou ded edge as show i the picture.
7.6 Glue the four ose blocks together starti g from NB-1 o
the bottom to NB-4 a d glue the assembly to the top of the TSU
back plate agai st F-1.
7.0 OSE AD TSU (TELESCOPIG
SIGHT UIT) ASSEMBLY

AH-1F COBRA—ELECTRIC PAGE # 10
APPROACH EGIEERIG
AH-1F ELECTRIC MECHAICS
7.7 Sa d the ose blocks flush with the top of the cross sheet-
i g o the fuselage ose. Sa d a small radius o the fro t of the
ose block.
7.9 Cut out the TSU sa di g templates from the sticker paper
a d stick to the fro t of the sight u its. Sa d back about 1/4”
arou d the sa di g template.
7.8 Pu ch out six 1/4” balsa telescopi g sight u its. Make two
sets of sight u its by glui g 3 T-2’s together for each side.
7.10 Glue o e T-1 betwee the two TSU assemblies a d o e
T-3 o each side of the assembly. Sa d the glued assembly to
the desired fi ished shape.
7.0 OSE AD TSU (TELESCOPIG
SIGHT UIT) ASSEMBLY
otes:
T-1
T-2