M. K. Bengtson Sopwith Pup 40 Model Instructions - page 7
Sopwith Pup 40” Page 6
Copyright© 2005‐11 M.K. Bengtson All Rights Reserved Rev 09/11
horizontal stabilizer. Glue the horizontal stab/elevator
assembly onto the fuselage. If using pushrods, slip the
elevator control horn onto the wire pushrod end and, with
the servo and the elevator centered, glue the horn into the
slot. Then glue the vertical stabilizer and rudder assembly
into the slot in the horizontal stabilizer. In a similar
fashion as the elevator, slip the rudder control horn onto
the wire pushrod end and, with the servo and the rudder
centered, glue the rudder control horn into the slot.
Pull‐Pull Elevator Set Up
Fitting the Rigging Wires
Use strong thread or Kevlar™ fishing line or elastic
beading cording to simulate rigging wires. Use small
screws, fishing hook eyes, straight pinheads or small
eyelets to attach the lines. These “wires” can add a degree
of strength to your model.
Rigging Wire and Pilot Detail
Windsock Datafile “Sopwith Pup “publication has details
on placement and markings.
Available at
http://www.byrdaviationbooks.com/
Battery hatch
Fashion a battery hatch from 1/32” plywood
Balancing The Model
Balance the model at the point shown. It is best to position
the battery to do this operation.
FLYING
Chris Goodchild’s original maiden report using previous
versionʹs power system:
“Just a short note for now to let you know that this
evening there was a Sopwith Pup on dusk patrol over our
local school playing field!
YES SHE HAS FLOWN!!!!!!
I flew her myself, on my own so unfortunately no flying
pics at the moment but she flew beautifully! This is the
first model I have built where I have not had to dial in
ANY clicks of trim. I had 3 flights in total using 2 950mah
KAN packs and felt very comfortable with her by the end.
I took some final photos at the field ʹjust in caseʹ and then
went through my final checklist before deciding to try a
quick test hop to get the feel of things. So, I pointed her
into the very gently breeze and gradually pushed the
throttle forward whilst holding in some up elevator to
keep the tail down. She picked up speed quite quickly
and only needed a touch of rudder to correct her line
before she rose off the ground. I cut the throttle and she
touched down and gently nosed over onto the cowl
mainly due to the grass being a tad too long. She had
committed aviation!
Now to re‐gather my composure, settle the nerves down
and prepare for a ʹrealʹ flight. Again she headed off a great
pace and was in the air in next to no time. First thing I
noticed was that she was tracking straight and true in the
air without the need for even one click of trim on any
control surface! (Thatʹs a first for me! ). She was flying
beautifully and I throttled back to about 1/3 to maintain
altitude while I did a few circuits to get the feel of her. The
480 motor in a 4:1 gearbox and 10x7 APC slow‐fly prop
were providing ʹbagsʹ of power. I got to a reasonable
height and tried some stall test, which were very un‐
dramatic with no signs of dropping a wing. I then cut the
power to see how rapid the decent was, well one word
says it‐‐GLIDER! She literally glides at a very shallow