Pilatus PC-21 - HT-Modellbau

Building instruction PC-21 Version 0.5e/ 30.10.2008 

Building instruction 

PC-21 

www.jetarrows.com 

1/32 www.ht-modellbau.ch


Table of contents 

1 Technical Data .........................................................................................................................2 

2 Kit contents: .............................................................................................................................4 

3 Recommended accessories.......................................................................................................5 

4 Fuselage....................................................................................................................................6 

4.1 Frame................................................................................................................................6 

4.2 Wing tube.........................................................................................................................8 

4.3 Turbine assembly .............................................................................................................9 

4.4 Turbine cover .................................................................................................................10 

5 Wing.......................................................................................................................................11 

5.1 Ailerons..........................................................................................................................11 

5.1.1 Ailerons hinges.......................................................................................................11 

5.2 Landing flaps..................................................................................................................13 

5.3 Landing flaps covering...................................................................................................14 

6 Elevators.................................................................................................................................17 

6.1 Elevator hinges...............................................................................................................17 

6.2 Elevator servo.................................................................................................................17 

6.3 Elevator assembly ..........................................................................................................18 

7 Rudder....................................................................................................................................19 

7.1 Rudder hinge ..................................................................................................................19 

7.2 Rudder linking................................................................................................................19 

7.3 Rudder flaps ...................................................................................................................20 

8 Cockpit and cab frame ...........................................................................................................21 

8.1 Cockpit rear wall............................................................................................................24 

8.2 Cockpit attachment.........................................................................................................25 

8.3 Canopy and framework................................................................................................. 26 

9 Landing gear...........................................................................................................................27 

9.1 Nose landing gear cover.................................................................................................27 

9.2 Main landing gear cover.................................................................................................29 

10 Control throws and Centre of gravity.................................................................................31 

10.1 PC-21 1:3.7 (big)...........................................................................................................32 

1 Technical Data 

Scale 1 : 4.8 1:3.7 

Length 2.38m 2.98 m 

Wingspan 1.85m 2.38 m 

Weight From 12kg From 19kg 

Engine 

Turboprop 

JetCat SPT 5 

Controlled functions Ailerons 

Elevator 

Rudder 

Break flap 

Engine 

Front wheel 

Undercarriage 

Wheel breaks 




2 




Kit contents: 

1 x fuselage GRP/CRP 

1 x turbine cover GRP/CRP 

1 x milled plywood stretching set 

2 x wings 

2 x winglets GRP 

1 x wing tubes 

2 x Elevator (GRP or Styro Balsa) 

1 x ruder GRP 

1 x canopy framework GRP 

1 x canopy clear 

1 x Cockpit from ABS with plywood parts 

1 x GRP Spinner 

1 x mounting set 

3 




Recommended accessories 

Function 

Accessories 

Ailerons, Elevator, Rudder 5 x Futaba F-9206 

Nose landing gear servo Futaba F-9202 

Landing gear 

HT-Modellbau (Jet-1A) 

Engine Turboprop JetCat SPT 5 

4 




Fuselage 

All GRP parts has residues from Parting agent and need to be cleaned 

If necessary rework the cut off seam. 

4.1 Frame 

Glue the front undercarriage support like 

the image show. 

picture 1 shows the den nose gear pit 

Cut the front undercarriage cover after the outliner. 

Resins the frame with epoxy mixture (epoxy thickened with micro balloon and cotton flakes) in 

the fuselage like the picture shows. But rough on first the fuselage with sand paper. 

picture 2 shows the glued front 

undercarriage cover 




Insert the front and back turbine frames in the fuselage and check if the positions fit with your 

turboprop engine. 

Then resins the frame with epoxy mixture (epoxy thickened with micro balloon and cotton flakes) 

in the fuselage like the picture shows. But rough on first the fuselage with sand paper. 

picture 3 shows the mounted front turbine 

frame 

picture 4 shows the mounted back turbine 

frame 

4.2 




Wing tube 

Coat the wing tube with separating means. Insert the guide tube at the right position in the 

fuselage and mount the wing tube. Afterwards resins the guide tube with fabric glass-chamfers. 

picture 5 shows the wing tube 

4.3 




Turbine assembly 

First cut out the holes for the two tail pipes (specify position with the turbine). Lay out the cover 

with thermal protection mat. 

picture 6 shows the inserted turbine 

picture 7 shows the turbine cover from the side 

picture 8 Shows the tail pipe 

Downwards 

Note: the tail pipe must be inserted left 

downward, quite upward. (See picture) 

Upwards 

4.4 




Turbine cover 

picture 9 shows the turbine 

cover 

First, bore on both sides of the cover the holes for the two turn closures according to the picture. 

Then resin a support with the help of stick. After hardening of the turn closures can be mounted. 

Afterward mount the linkage (a1) for the fixation of the pins B treat it with parting agent and then 

resins in together with the bowden cable. This gives the attachment of the cover. 

picture 10 shows the turbine cover 

cover 

B 

A 

(a2) 

55 

C 

(a1) 

20 

225 

110 

Bowden cable 

Bowden cable 

fuselage 

Bore afterwards the ∅ 3 mm holes for the pin C in the fuselage. Parting agents the fuselage and 

bore the two holes in the fuselage for the pins B somewhat more largely than the pins, so that the 

cover fits. The same with the two holes for the pins C, but bore this time the holes in the cover 

more largely! Grinding the pins (C to sticking in the cover and B in the fuselage). Install the 

cover with pins and Bowden cable and examine if it fit. 

If everything fits, stick both pins C in the cover and B in the fuselage with Epoxy resin mixture. 

At the same time also the piece Bowden cable pipe for the attachment will be glued. 

For this assemble the linkage (a2) and align it. After hardening curing the linkage (a2) at the end 

with a black felt-tip pen mark, mount the cover and close the shutter so that the black colour is 

painted to the fuselage. Now bore the two holes for it. 

5 




Wing 

5.1 Ailerons 

5.1.1 Ailerons hinges 

small middle big 

2x Ailerons outside 2x Ailerons middle 2 x Ailerons inside 

8 x Elevator 

3 x Rudder 

Put the fuselage upside on a table, mouth the wings and fix them. Insert the landing flaps and 

positioning ½ mm distance between flap and wings. Hold the ailerons and mark the position for 

the hinges. Afterward you can cut the slots. To glue put slightly below resin mixture, and mouth 

the aileron with mounted hinges (Approximately 1.2-1.5mm distance between ailerons and wing), 

and fix it at each transition with screw fixation, so that the rudder are equal. Then the landing 

flaps hinges can be glued with resin mixture. After curing remove the wings and glue the hinge 

definitely in the wings. 

At the elevator and rudder exactly the same approach. 

picture 11 Fix the aileron during gluing 




picture 12 Cross section of the rudder hinge 

5.2 

www.jetarrows.com 12/32 www.ht-modellbau.ch


Landing flaps 

For the landing flap hinges on the cuts in 

the wing are already made. On the two 

flaps they must be cited as shown in the 

picture. 

picture 13 shows the landing flap hinge 

with the servo 

M2x10 countersunk 

When you have wood wings, the servo 

fixation is done in the same way as for the 

elevator. 

For the CSF wings they are already 

finished. 

Please note that the linkage is mounted as 

shown in the picture. 


with the servo 

The hinges assemble (with screw store varnish secure). 





5.3 Landing flaps covering 

The landing flap hinges can be switched after 

covering or squirting with the settled ABS parts 

as in the illustration. 

picture 16 shows the cover of the landing flap 

hinges 

picture 17 shows the cover of the landing flap 

hinges 




Near the linkage 

1mm plywood 

Near the linkage M2.5 x 10 

countersunk screw 

Fixatio n and 

Cuttin g near the linkage 

Near the linkage 

2mm + 6mm plywood 

picture 18 shows the landing flap covering 



Place for the linkage 

13 mm 

6 mm 8 mm 

1 mm 

3 mm 

picture 19 shows the landing flap covering from the top on the linkage 

13 mm 

3.5 mm 

3.5 mm 

5.5 mm 

5.5 mm 

picture 20 shows the landing flap covering from the top 

6 




Elevators 

6.1 Elevator hinges 

The countersinks fort he rudder hinges are already done. Glue the elevator hinges like the one on 

the ailerons. 

6.2 Elevator servo 

The servo fixations is already resins in the elevator (prepared for Futaba servos) 

picture 21 Shows the Servo fixation 

After the installation of the Servos using rubber 

sleeves (a servo component) cut out the GRP 

servo cover after the outline. Leave the cover 

part for the linkage as in the picture somewhat 

longer. Bore afterwards the holes for the 

attachment and the cover with screws 2,5x12 

install. 

picture 22 shows the servo cover 

6.3 




Elevator assembly 

The elevator is installed with aluminium putting pipe and with both CRP pegs. First the two pegs 

on a page sharpen. Install afterwards the elevator for control. If everything fits bonds the two 

pegs with resin mixture into the elevators. 

Attention: Peg first with parting agent treats! 

picture 23 shows the elevator 

If everything is dried, the drilling for fixing bolt can take place. Indicate in addition the position 

of aluminium to putting pipe at the elevator and the drilling for the screw make. Afterwards 

elevators again install and into the putting pipe through the drilling make. Bore afterwards a M4 

threads. 

picture 24 shows the elevator attachment 

45mm 

7 




Rudder 

7.1 Rudder hinge 

The 3 slots for the hinges in the rudder are already done. 

Glue the hinges like on the ailerons 

7.2 Rudder linking 

Insert the servo into the rudder and the position of the rudder horn and linkages mark. After 

milling out, resins the rudder horn with resin mixture. Mill out a slotted hole in accordance with 

the design for the linkage. To the linkage the servo with the yoke begins screws in. Screw now 

the linkage through the hole on the yoke. Screw in best completely, since no lock nut can be 

installed with screw Loctite to secure. 

picture 25 shows the position of the rudder servo 

25 

picture 26 shows the position of the rudder servo 




Putting pipe in front with wood peg from above push in and by the fuselage bore From downside 

with a plastic plug fasten. The pipe either sticks together in the vertical stabilizer or with the 

servo pit bolt. 

165 mm 

parallel 

12 mm 

Putting pipe 

Wood peg 

picture 27 shows the rudder attachment 

Plastic plug 

7.3 Rudder flaps 

Cut the slots for the rudder flaps as shown in the picture and glue them in. 

8 




Cockpit and cab frame 

Cut put both cockpit tubes, stick together and strengthen with plywood parts. 

picture 28 shows the cockpit 

picture 29 shows the cockpit floor 

Stick seats and instrument panel in accordance with the illustrations. 

picture 30 shows the seat 

picture 31 shows instrument panel 


21/32 www.ht-modellbau.ch


Spray the cockpit with spray box dark grey or black. Bond the Seat. 

picture 32 shows the sprayed cockpit 




8.1 




Cockpit rear wall 

Glue the cockpit rear wall from the 3 ABS together 

picture 33 shows the cockpit rear wall 

Glue the plywood mounting stuck in the fuselage and fixes the rear wall with double tape or a 

screw. 

picture 34 shows the fixation of the cockpit rear wall 

8.2 




Cockpit attachment 

For the attachment of the cockpit in the rear part of the cut-out a plywood board is bonded at a 

value of 185mm. Fasten the cockpit with klett catch to the board and in front. 

185 mm 

picture 35 shows the Cockpit attachment 

150 mm 

Brett 

8.3 




Canopy and framework 

Canopy frameworks of the outline out with the 

friction disk cut out. 

Transparent hood cut out and with the cab frames 

stick together. 

Cab frame attachment 

picture 36 shows the cab attachment 

9 




Landing gear 

9.1 Nose landing gear cover 

Cut the cover in the middle longitudinal. Then make the cut-outs for the hinges in the fuselage. 

picture 37 Shows the closed nose landing gear cover 

Cut-outs in the fuselage for 

the hinges 

2/3 

1/3 

~5mm 

~5mm 

M3x10 

countersunk 

After bonding the hinge (on the fuselage, they can be screwed) glue 6 screws with Flexzap like 

shown in the picture (previously rubbing). 

Then install three silicone tubes between the two covers according to the photos. 

picture 38 Shows the nose landing gear cover 




picture 39 Shows the silicon tubes on the nose landing gear cove 

9.2 



Main landing gear cover 

The holes in the main landing gear cover are already drilled. 

M2x5 countersunk screw 

Stopp nut M2 

27 mm 

picture 40 shows the main landing gear cover 




168 mm 

picture 41 shows the cover fixation on the main landing gear 




10 Control throws and Centre of gravity 




10.1 PC-21 1:3.7 (big) 

Aileron 

+20, -15 mm (based on the wing outside) 

Elevators 

± 25 mm 

Rudder 

± 40 mm 

Landing flaps Pos 1 15 mm (measured with the fuselage) 

Pos 2 65 mm 

Expo aprox. 30 – 40 % depending upon taste. 

The batteries should be place in front as far as 

possible (receiver, valves on servo board of 

the nose gear), the emphasis is measured 200- 

210 mm from the wing front edge. With the 

installation of the servo cables on the fact it 

respects that they are distant from the battery 

and automatic controller as far as possible. 

The antenna should be shifted outside of the 

fuselage. 

200 – 210 mm

Pilatus PC-21 - HT-Modellbau

Create successful ePaper yourself

Delete template?

Save as template?