and Rockets visitor Wells S. requested this article and plans of the Cardinal, from the February
1972 issue of AAM. The Cardinal, per its designer Dan Santich, was created in order to have a competitive
pattern ship that could not only fly the entire FAI course, but do it gracefully and effortlessly.
A search did not reveal whether he ever went on to win an FAI contest with his Cardinal.
by Dan Santich
Distinctive-Looking American-Designed Plane Created for the FAI Pattern Maneuvers
Tatone engine/nose gear mount used and recommended for balance and heat sink effect.
Other than gear and engine, the profile is clean - offering low drag. Laminar wing allows speed
and needs large maneuvers, but in this case, also permits stable, slow flight.
Someone once said, "What this country needs is a good five-cent cigar." Well, there is a new
saying that goes, "What this country needs is a good FAI Pattern ship." Who said it? Just about
everyone after the FAI Championships two years ago when this model was designed. We do not have
a ship capable of the precision and grace required by the FAI Pattern. Don't get me wrong, we have
plenty of airplanes that will perform the FAI Pattern, but there is quite a big difference between
simply doing the maneuver and doing it correctly. Let's use the takeoff as an example. Just about
anyone can perform this to one degree or another. You just aim it, pour on the coal and unglue it
from earth when it has flying speed. It's simple, right? WRONG!
A good precision takeoff is a difficult maneuver, but a beautiful one if done correctly. It must
track absolutely straight and lift smoothly from the ground in a fairly flat attitude. It takes
a good pilot to do this, but more importantly, a good airplane. If a ship is not set up correctly
one will have problems, even if he is the world's greatest pilot. Let's take another one on the
spin. Get some altitude, head into the wind and cut the power. Bring the nose up, and as it stalls,
hold up elevator and right or left rudder and aileron. It is at this point that the airplane takes
over. All the pilot can do is watch as it rotates. It will either spiral or spin. If it does spin,
how fast does it rotate? I have seen some pattern ships that would spin so fast it was hard to even
count the turns.
Stopping it is something else. If the spin is rapid, the chances that you will stop it right
on heading are remote. So, it follows that the slower the ship spins, the easier it is to stop it
when you want to - not a half turn after you neutralize the sticks. Again, it is the airplane dictating
the maneuver, not the pilot.
The Cardinal is the result of countless hours of research and study, as well as trial and error.
Every aspect of the ship has a planned purpose. Each maneuver in both the AMA and FAI pattern was
analyzed and the ship designed accordingly. It will actually climb while knife edging with full
top rudder. It does not wiggle even the slightest on the double stall turn and will tail slide better
than any ship I have seen. Wind has no adverse effects on it - in fact, it even helps you track
straight in the loops and eights. Takeoffs are absolutely beautiful; it is almost impossible to
tell exactly when the ship leaves the ground, it is that smooth. The spin rate is quite slow and
it stops immediately when the sticks are neutralized. To achieve a faster spin rate and to do the
loop with one and one-half snap, just move the clevis for more elevator throw. It will slow-fly
at near walking speed, which enables you to put it right smack in the center of the circle every
Cut out all fuselage parts and mark with a ball point pen. Epoxy doublers to fuselage sides.
Do not use white glue as it will warp the balsa. Glue stringers to rear half and, when dry, epoxy
bulkheads F3 and F5 in place. Drill F2 for Tatone side nose gear mount, install blind nuts, and
epoxy in place. Wet the nose section forward of F2 and use a 2-in. dia. bottle or can to form the
rounded nose section by sticking the bottle between the wetted sides and wrapping with rubber bands.
When dry, add FIA and epoxy vertical triangle braces to the front and rear of F2. Glue remaining
bulkheads in place making absolutely sure it is aligned properly - the fuselage must be true.
I built mine on a small card table in our apartment here in Japan, and I got it straight, so
you lucky fellows with fabulous workshops and building jigs should have no excuse. Epoxy top nose
block in place (after it has been hollowed out) and glue on upper and lower portion of fuselage.
Use a razor plane to shape after everything has dried. Add F1 and lower nose block with epoxy after
hole is drilled for nose gear to go through. Sand to shape and make cutout for engine. Shape and
glue vertical and horizontal stabs in place, again being very careful of alignment.
Since a foam wing is used, not much explanation is necessary. Select the lightest possible foam
and make sure you epoxy gauze tape on after the wing is sheeted. Add lower portion of fuselage to
bottom of wing. Fit wing to fuselage and add fillets. You will have to form your own main gear due
to its unusual shape and length. Make sure you use good hard wire. The wheel fairings are made from
aluminum stock, but 1/32 plywood could also be used. Strip ailerons are used; however, perhaps the
puritan would prefer the center-hinged, barn-door type. Take your pick. I have found that the rolls
are cleaner by using very large strip-type ailerons, since very little throw is required. They also
make the wing easier to construct.
A word about the "funny airfoil." It is the NACA 64 A215 and although it is a laminar-flow, low-drag
airfoil, it has excellent slow flight characteristics. It has been used on such successful ships
as the Orion, Thunderstormer, and Twister. If you prefer, go ahead and use a fully symmetrical one.
The "easy does it" method of finishing is my favorite and that is how this one is done. It is
light, quick, and very attractive. "What is the "easy does it" method?" you ask. Send off to Hobbypoxy
and they will send you all the poop on how it is done correctly. Here is my "easy does it" method:
I use Sig epoxy because it cures fast. Mix about three oz. each of resin and hardener, thin to a
vodka consistency and brush on the bare wood. Let cure Repeat the same procedure only not so thin
this time. The reason for the very thin first coat is to let it soak into the wood to increase the
strength of the balsa. After the second coat has cured, sand down with coarse sandpaper and remove
all bumps and fuzz. Sand it once again using a finer grade paper this time. Fill all nicks, cracks,
and dents with Epoxolite and after it is cured, scrape it down using a double-edge razor blade.
Do not use stainless steel blades, as the edge goes off almost immediately. At this point the grain
should not show. If it does, add another coat of thinned glue and scrape down again. Wet sand it
and spray on a coat of gray Hobbypoxy (black and white mixed). Wet sand any rough spots and spray
on your color.
Since I have gone into so much detail, there is not much left to say, except try to be selective
in your choice of wood and keep the weight down. Do not try to "beef it up." I learned a long time
ago not to sacrifice weight for strength. Mine tips the scale at just over 6 1/2 pounds.
The AMA Plans Service offers a full-size
version of many of the plans show here at a very reasonable cost. They will scale the plans any size for you. It is always
best to buy printed plans because my scanner versions often have distortions that can cause parts to fit poorly. Purchasing
plans also help to support the operation of the Academy of Model
Aeronautics - the #1 advocate for model aviation throughout the world. If the AMA no longer has this plan on file, I
will be glad to send you my higher resolution version.
Try my Scale Calculator for Model Airplane Plans.
Posted May 20, 2013