marston PteroWorks 52" Pterodactyl User manual

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
1
Thank you for purchasing this 52” Pterodactyl kit. It is unlikely that anyone else at your ying eld
has anything like this. It is truly a distinctive design, and yours will no doubt be different from
mine, making it a one of a kind model.
This is not a beginner’s kit, but it does not require expert building skills. The kit is fairly complete,
and if you have built and covered a wood model before you should have no trouble here. Take
your time, be careful and have fun with the build. You will need thin and medium CA to assemble
the airframe. Much of the gluing can be done by getting the wood in position rst and then using
thin CA which will wick into the wood joint. Be sure to dry t pieces rst before applying glue.
This airframe requires some experience to y, but if you have successfully own a plane with
ailerons, you should have no trouble at all launching, ying and landing this bird. The wing loading
is very reasonable, and if set up properly there should be no surprises.
This instruction manual is available as a PDF on line at www.pteroworks.com/ptero_52.htm.
The photos in this manual can be enlarged for greater clarity in the PDF.
Wingspan 52 1/8”
Length 31”
wing area 330 square inches - 2.29 square feet
weight RTF 24-28 oz. (with a 3s 2000 mah li-poly battery)
wing loading 11 oz/square foot
Included in this kit: 15 sheets of laser cut wood (all wood required), 65” x 36” rolled plans, front
and rear carbon wing spars, 1/8” x 3/4” carbon wing locator, 1/2” aluminum wing locator tube,
#6-32 x 2” nylon wing bolts and blind nuts, instructions.
Additional gear required: two small brushless outrunner motors with a kVa of about 1400-1500
rpm/v (Axi 2208 or equal), two 6 x 5.5 props, two 10-20 A ESCs, four mini servos (HS-45HB for tail
and HS-65HB for ailerons) and a 2000 mah 3s Li-poly.
Requires covering material (Ultracote or Oracover recommended).
Instruction Manual for the Marston 52” Pterodactyl
Thanks,
Ron Marston
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Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
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Wing
1. Cut carbon spars to proper length.
forward spar - .240” dia. 41.40”
rear spar - .156” dia. 45.40”
2. Layout all ribs on the plans then carefully feed them
onto the forward spar (.240”).
Do NOT glue yet. (B)
3. Carefully feed rear spar (.156”) onto ribs. Spin spar
as you push to facilitate feeding.
Do NOT glue yet. (C)
4. Attach 4 leading edge pieces. Lay parts on plan to
facilitate alignment. Do NOT glue yet. (C)
5. Glue doubler/connectors to leading edges at the
motor area and at the center of the wing. Then glue
motor mounts after ensuring the hole pattern will
work for your motors. If necessary, use supplied
blank motor mounts and drill appropriate holes for
your motors. Check motor mount incidence angle
for 0 to 1/2 degree of down thrust. (C)
Glue rib (12) in place on left and right sides of wing.
Note: Any twist in the wing should be turned to
create wash-out (trailing edge of wing at tip is
raised compared to trailing edge at root). (D)
6. Glue bottom trailing edge center ply strengthener
along with balsa center bottom trailing edge.
7. Glue remaining bottom trailing edge balsa pieces to
ribs. NOTE: many of the wing sheeting pieces
are different top and bottom. Top pieces are
marked with a “T” and bottom pieces are
marked with a “B”. Assemble with “B”s and “T”s
facing inward to avoid having them show. (D)
8. Sand rough airfoil into wing tip pieces and glue to
rib 12 on left and right sides. Sand about 5 degrees
into face where it mates with rib 12 so the wing tips
angle up slightly.
9. Lay wing on plans and ensure ribs are in proper
position and that there is no twist in the wing. Use
thin CA and glue all ribs to the carbon spars
and the leading edge pieces.
10. Stack both screw tower pieces together and glue in
place at center trailing edge where the screw holes
are. Sand top to match rib 1 prole. (E)
11. Sand then glue top center trailing edge piece to ribs.
A
B
C
D
E

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
3
12. Glue remaining top trailing edge pieces to ribs. (F)
NOTE: Wing sheeting is laser cut oversized
to allow for sanding to a perfect t. Soak
sheeting in water for a few minutes rst to
ensure it conforms to compound curves.
13. Glue bottom covering behind motor mounts. Check
t of motors rst to ensure mounting clearance.
Mount motors at this stage if necessary. (G)
14. Glue bottom leading edge sheeting. Sand sheeting
pieces as necessary to get a good t. (G)
15. Glue 1/8” x 3/4” carbon rod wing retainer into gap
at center leading edge of wing. (H)
16. Check servo t and glue in doublers for aileron
servos. Glue or tape servos in place. Servo arms
should extend out on the bottom side of the wing.
Run wires for servos through forward holes in ribs
and be sure to allow about 5” of wire extending
out of the center of the wing. (I)
17. Run wires for motors through same forward holes
in ribs as the servo wire. (note: see ESC wiring
note on last page) (I)
18. Carefully sheet top of wing. Sand pieces as
necessary to ensure a good t. Soak sheeting in
water to ensure sheeting conforms to compound
curves. If you desire, cut access hatches into
sheeting for servos. (J)
19. Glue balsa pieces to rear carbon spar where
ailerons will attach. (J)
20. Use 3/16” wide balsa strips to cap all ribs, top and
bottom. (J)
21. Use scraps of wood to ll gaps around motors, and
anywhere else it’s needed.
22. Sand and ll wing as necessary to make it pretty.
NOTE: Spend time on the sanding - it can
transform a mess into a thing of beauty!
F
G
H
I
J

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
4
Head and Neck
1. Carefully remove all head and neck parts from the
balsa sheets and sand as necessary. (K)
2. Fit 2 head cross pieces to neck sides. (L)
3. Fit 3/16” center neck piece in-between neck sides. Hold
assembly together and wick thin CA into joints. (M)
4. Fit top 3/16” center wing locator piece and glue with
thin CA. (N)
5. Fit, sand and glue shoulder (3) pieces to neck
assembly. (O)
6. Fit and glue top and bottom short-grain neck sheeting. (O)
7. Carefully t shoulder pieces (1) and (2) together, sand
angle and glue. Check t with shoulder (3) pieces. (P)
8. Glue shoulder pieces from step 7 to neck base assembly.
K
L
M
N
P
O

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
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9. Sand diagonal angle into cross pieces that connect
the head to the neck (from step 2) as necessary
and t and glue head sides to diagonal pieces. (Q)
10.Sand and t bottom head sheeting. Glue in place
with thin CA. (Q)
11.Glue about 2 oz. of lead in cross pieces in head
before gluing top head sheeting in place. (Q)
12.Fit and glue top forward sheeting in place, then t
and glue top rear sheeting in place. (Q)
13.Sand assembly until pretty. (R)
Tail
1. Carefully remove all tail parts from the balsa sheets
and sand as necessary. (S)
2. Sand square all surfaces that will but-glue together.
3. Fit and glue base pieces to main tail pieces. (T)
4. Glue trailing edges to main tail pieces. (T)
5. Sand leading edges round, and taper trailing edges.
6. Sand or cut a 50 degree angle into the bottom
forward bases where they will attach to the body.
Be sure to keep track of which will be the left and
right tail pieces. (U)
7. V-tail angle should be 108 to 112 degrees. Use
supplied angle jig to set tail angle on body.
8. Sand assembly until pretty.
2 oz lead here
Head and Neck (cont’d) Q
R
S
T
U

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
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Body
1. Carefully remove all body parts from the balsa
sheets and sand as necessary. (V)
2. Fit and glue Head/Neck assembly to one side
then the other of the main body. Check alignment
against plans and make sure both sides of the
body are square before gluing. (W)
3. Glue top rear (long grain) piece to the body sides,
taking care to align the top of the surface ush
with the top of the sides. (X)
4. Glue 3/32” center doubler to long grain rear piece
from previous step. (X)
5. Fit and glue 3/16” screw hole doubler to under side
of top rear piece. (X)
6. Fit and glue 3/16” thick rectangle pieces, starting
with the shortest piece in the groove at the bottom
of the shoulders to form the bottom of the body.
Gently bend pieces to get some curvature to match
the body. (Y)
7. Fit and glue 3/32” thick sheeting at the rear
bottom of the body. (Z)
8. Sand or cut a 50 degree angle into the sides of the
body at the top rear where the tail pieces will rest
on them. Fit the tail pieces and sand until the angle
and alignment are good, then glue tail pieces in
place. Check with the wing in its saddle to ensure
everything sill be square. (Z)
9. Check t of wing to body and alignment of bolt
holes. Fit and glue #6-32 blind nuts under the wing
screw down holes.
10.Sand assembly until pretty.
V
W
X
Y
Z

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
7
Final Assembly
1. Sand ailerons and rudder-vators to a nice taper
at the trailing edges. Also sand an angle where
surfaces will attach to wing and tail to allow for
downward deection.
2. Glue supplied control horns into all 4 control
surfaces. (This may be better to do after covering).
3. Check the t of the wing in its saddle and sand if
necessary.
4. Fit and glue 1/8” ID aluminum tube into notch in
neck. Be sure it mates well with 1/8” carbon rod on
wing and that the wing lays at in its saddle.
5. Assemble horns for the head (don’t glue to head
until after covering).
6. Mount the tail servos in the rear of the body.
Use small HS-45B or equivalent servos. Run the
linkage out the rear of the body (see a, b, c).
7. Sand everything until pretty.
8. Cover the Pterodactyl. Allow yourself at least two
days to do this. Go slow and take your time, you
will be happy you did later. Because of the unique
nature of this airframe, some parts of it will be a
challenge to cover well. The neck and leading edge
of the wing have compound curves. A trim iron will
be helpful to cover these areas.
I STRONGLY recommend using Ultracote or
Oracover or a similar stretchy material. I do NOT
recommend using Monocote, as it does not stretch
as well. Balsarite can be used to facilitate the
adherance of the covering to the wood.
9. Cut two #6-32 x 2” nylon screws to proper length
and use to secure the wing to the body.
10. Use a good lightweight hinge tape (like
Graupner’s) and tape the control surfaces to
the airframe.
11. Hook up the servos to the control surfaces.
Use .050”-.060” Z-bend wire for the ailerons, and
something light-weight in a housing for the
tail surfaces (rudder-vators).
a
b
c
d

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
8
Final Assembly pictures

Copyright © 2012 Ron Marston all rights reserved rev. D 2/12
9
Flying the Marston 52” Pterodactyl
The Center of Gravity should be set to the center of the forward (.240” diameter) spar, plus or minus
1/8”. Do not attempt to y with the C/G outside of this range. One to two ounces of lead in the head
will likely be required to achieve this. Even with the lead, the completed airframe should weigh no more
than 28 ounces with a 2000 mah 3S Lipoly battery. The wing loading is in the parkyer range, so you
should have no surprises with the ight characteristics.
Control surface throws should be high for the ailerons and low for the elevator (rudder-vators). Set
differential (more up travel than down) for the ailerons to about 50%. Aileron throw should be 3/4”
- 7/8” up and 3/8” down, measured at the inside edge. You can set up spoilerons for shortening the
landing, if your transmitter allows for it. Both ailerons should rise to about 3/4 of their total up travel. A
small amount of down elevator compensation (about 5%) should be mixed in with the spoilerons.
Because the tail surfaces are short coupled (not very far behind the wing) the Pterodactyl does not need
large elevator throws. Set the travel to about 1/2” up and 3/8” down. Use exponential of about 20% for
smoother pitch control.
I recommend putting some clear packing tape on the
belly to protect the covering during landings.
NOTE: When using two speed controls with BECs
(Battery Elimination Circuits), be sure to disable one
of them, by removing the red (positive) wire from
one of the speed controller’s receiver connector
(see diagram at right).
Good luck, have fun and happy ying!
connect to receiver
or Y harness disable positive lead on one ESC
connect to battery
Motor
controllers (ESC)
with BEC
Motor
brushless motors with two ESCs