Paul Janssens, who
is known to many of us as a leading continental PSS
model designer and flyer, has contributed this article
on what may well turn out to be a most popular PSS model
for beginners. Construction is quite straight forward
and Paul has a plan and canopy available for intended
builders.
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The Skyraider is one of
the last prop driven warplanes. It’s an
amazing aircraft, it was built around the
most powerful engine available at that time,
a 3350Hp Wright. This engine was also used
in the Lockheed Constellation. The ‘Spad’,
as pilots called the Skyraider, didn’t see
much of WWII but was reintroduced in Korea,
where it proved to excel in ground strafing
missions. It was fast, could carry more
than its own weight in payload and could
take lots of damage and keep on flying. One
pilot even managed to take off from an
island with the wings still folded, but the
flight was only a short one. Both crew
members survived. The first Skyraider flew
in March 1945, 3180 were built and they
didn’t retire until 1968, an impressive
service life! |
I saw my first Spad when a Belgian
Army Colonel bought one, he flies it occasionally, but
the cost of 200 litres of high octane fuel plus 50
litres of oil per hour keeps him grounded most of the
time. In La Ferte Alais I saw a Skyraider in
maintenance and the shear size of the thing inspired me
to draw up this plan. Those who build my Spad will
agree that it’s a good and easy flyer. I love my
Skyraider.
The building method seems complex at
first, but if you stay with these instructions things
will start falling into place very soon. You can build
this model in about 50 hours.
The wing is the classic foam/veneer
construction. Cut the foam to shape using the top view
and both wing section templates, then cover the foam
with obechi or balsa veneer. The aileron torque rods
can be fitted before or after covering. Glue the balsa
leading edges and wing tips into place and sand to
shape. Join both wings to the correct dihedral, as
shown on the plan, then strengthen with a band of
fibreglass. Install the hardwood dowel and glue into
place the ply reinforcement for the nylon bolt. Cut out
the ailerons and sand to shape.
To build the engine cowling and gear
wells, start by reproducing all templates on thin
cardboard, such as a Corn Flake box. All templates,
except for the engine cowling aft template need to be
reproduced in duplicate. Use pins to fix the gear well
side views on either side of a foam block and cut out.
Remove the side views, fix the top views on and cut
again. Repeat this to make two gear wells. Sand all
foam blocks to shape using 150 grit paper and smooth
with 600 grit paper.
Cover moulds with Solarfilm or brown
parcel tape, this tape can be heat shrunk with an iron
at low temperature. Make sure no resin can make it
through the tape, as this will dissolve your foam
mould. Apply a coat of de-moulding wax and put on 2
layers 160g/sq m glass cloth and resin, then a final
layer of 80g/sq m glass cloth. An hour later you can
put on a thick coat of resin and micro balloons
mixture. The next day, cut away the edges and sand the
parts to shape using 150 grit paper. The micro balloons
will give lot of dust, so protect yourself. Thanks to
the micro balloons you will get a quick result and you
wont have to sand into the glass fibre to get a smooth
shape. Finally, smooth with 600 grit and water. The
glass parts can be painted later or covered with
Solarfilm, try this method out, you’ll get a smooth,
easy and light finish and scratches are no longer a
problem!
Make the propeller hub from balsa,
cover it and glue into position on the engine cowling.
The fuselage is built on a blue foam
core, which needs to be lightened by hollowing it out.
You can pass a hot bicycle spoke through to make the
first hole, then pass your cutting wire through,
reconnect and cut. Use epoxy to join the fuselage
sections. Now you have to put all the balsa on,
starting at the front of the fuselage. Use contact
adhesive such as Copydex for this job to keep things
light and to get the job done fast. Reglue all balsa to
balsa seams with thin cyano and sand the fuselage to
shape.
The canopy is moulded from a hardwood
block sanded to shape, or can be ordered from me.
Install a seat and a pilot, as this will add
considerably to the realism of the model.
The stabilizers and fin are
conventional, use light balsa to keep the weight of the
tail section as low as possible. Install the engine
cowling onto the fuselage then smooth the wing and the
fuselage and cover with Solarfilm. If you cant find the
right colour, lightly sand the surface of the film and
spray paint the model to your taste. Make the arrestor
hook out of plastic tube, heated and bent to shape at
the end. You will find that inspite of the radio gear
being forward, you have to add ballast to the nose to
get the centre of gravity in the right spot. This is no
problem as the prototype was a bit on the light side, at
1.4kg the model is a floater that needs some ballast to
penetrate in very strong winds.
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The Skyraider was a success from the first
flight, no surprise, as this is a classic
glider shaped aircraft. The model is an
ideal first aileron model, with very stable
flight and docile stall behaviour. On
approach to the stall the model will start
wallowing but all controls remain effective,
even when the nose drops. Normal flight is
resumed with a height loss of about 10
feet. Aerobatics are fairly slow, which is
true to scale for this model. Rolls are
nice and straight and inverted flight needs
only a slight push on the stick. Approaches
and landings are a simple formality, as the
model has enough inertia to penetrate
turbulence undisturbed and she responds to
corrections without protest. |
A friend volunteered to build a
powered Spad from the plan and this model is now one of
the eye-catchers at our club. The airframe is like the
one on the plan, but with a ply firewall and the engine
and radio gear in classic configuration. There is ample
space inside the fuselage, so he included underwing drop
tanks – an idea I might copy for my PSS Skyraider.
Enjoy this docile beast – I know you’ll love her!
The Finished
model spans 134cm (53") and is 100cm (40") in length.
Plan and Canopy available from:
Paul Janssens
Gasthuisstraat 29, GEEL, 2440
BELGIUM
(see PSSA Plans page
for more details)
