M. K. Bengtson Sopwith Pup 40 Model Instructions - page 2
Sopwith Pup 40” Page 1
Copyright© 2005‐11 M.K. Bengtson All Rights Reserved Rev 09/11
Sopwith Pup
Thank you for purchasing the 1/8
th
scale Sopwith Pup
model for electric flight.
THE MODEL
A semi scale adaptation of the Sopwith Pup, this model is
designed to be easy to build and exciting to fly.
Sopwith Pup Finished Model
Model Specifications
Scale:
1/8
Channels:
R/E/A/T
Wingspan:
40ʺ
Wing Area:
550 sq in
Weight:
30 oz ready to fly
Power System: AXI 2217/20
Prop:
10x7
Wheels:
Balsa & plywood, Neoprene foam tires
Airfoil Type: Flat bottomed
Cowl:
Built up balsa and plywood
Covering:
Litespan or Polyspan
Decals:
Available on the website
BUILDING THE MODEL
Before Starting
A note about the photos: The photos were taken of an
earlier version prototype and the parts supplied may look
slightly different from them. Also the model has been
upgraded to include a dummy motor to house a brushless
outrunner. However, the concepts illustrated are the
same.
COWLING
The cowling is of built up construction using C1 and C2.
Assemble the Cowling
Construct front cowl ring by wrapping C1’s with 1/32”
thick plywood. The grain in the plywood should be
parallel to the short axis. To reduce weight, the inner C1
may be shaved or sanded down after cowl construction is
finished. Align the inside of the parts for proper
construction. Glue two C2s in three pairs and laminate
together. Then glue them to the previously assembled C1s
and plywood. Sand the C2 balsa to shape.
Cowl Assembly Detail
The cowl should now be sealed, sanded and primed until
no wood grain is left showing. Baby (Talcum) powder in
clear dope makes an excellent balsa sealer. Talcum
powder mixed in white glue makes excellent filler for
gaps or gouges. Sand down filler after it has dried.
WINGS
Wing Construction
Pin down, over the plan, the t/e, spars and wing tip,
gluing as required.
Top Wing Center Section