Aeronca Champ
by
Budd Davisson
When it comes
to picking their favourite post-war trainer, most folks
fall into line behind one of two airplanes: The Cub or
the Champ. Both have their supporters and detractors,
but all will admit that the little Aeronca Champ is the
only classic of the period to give the Cub a run for its
money in the learning-to-fly game.
The first
lines for the new airplane, the Model 7 Champion, were
laid on vellum early in 1944 and the airplane flew in
May of that year. Chief test pilot Louis Wehrung did the
honours. The official designation of the airplane was
7AC (Model 7, first variation, Champion) and it used the
A-65 Continental.
In laying out
the configuration of the Champ, designer Ray Hermes took
square aim at his primary competition, the J-3 Cub,
which by that time, was nearly a decade old. He made a
list of every one of the Cub's shortcomings and designed
them out of his new airplane. The final lines of the
Champ are the net result of Anti-Cub design goals.
Forward
visibility had always been a Cub weak point and Hermes
solved that in two ways. First, he put the pilot in the
front seat and, second, he raised the seating position
and dropped the nose so the pilot could see straight
ahead while on the ground. This is why a Champ appears
so high in the cabin, when compared to the Cub. The Cub
may have finer, sleeker lines, but the Champ pilot can
not only see where he's going but sits up in real
comfort (relatively speaking).
Cubs also came
in for criticism in the drafty arrangement of the door.
While the split door may be perfect for viewing sunsets
today, when the Cub was working for a living,
instructors and students alike cursed the leaky doors.
The Champion used a hinged, single-piece door not unlike
an automobile.
A little over
8,100 Champs were produced, most of which were the 65 hp
7ACs which ended production in April of 1948 to be
replaced by the 85 hp 7BCM (it was fuel injected and had
a larger dorsal fin, as well) which was ordered by the
military as the L-16A. The military then went to 90 hp
(fuel injected) and the nearest civilian counterpart was
the 7CCM. The most common civilian version to come out
of all of this was a combination of the A and B model
L-16, the 85 hp 7DC which had the larger dorsal and an
additional fuel tank in the right wing. Only 166 7DC's
were built before the final Champ was introduced, the 90
hp 7EC. The final Champ rolled off the Aeronca line in
January of 1951. It was Champ 7EC, SN96, N4749E. Anyone
know where it is today?
A good design
has a way of surviving and the 7EC is one of those. In
1954, Champion Aircraft of Osceola, Wisconsin, put the
7EC back into production where it continued to be
up-graded, eventually becoming the 7ECA Citabria in the
early 1960's.
Mechanical
Description
Champs use the
triangular aft-fuselage Gene Roche originally designed
for his little C-2 in the late 1920s. Because most
Champs have probably spent more time tied down
outside than in hangars, the plywood formers which fair
the fuselage into a square shape have to be considered
suspect. Bad fuselage wood isn't a major safety concern
but it takes time and money to replace it.
Other than
being triangular in cross section, there is little about
a Champ's fuselage structure that presents unique
inspection concerns. All steel tube fuselages share the
same corrosion concerns, especially in the rear of the
fuselage and in the strut carry-through tube under the
floor.
The trim
system is something else that the designer worked at to
make more efficient than that on a Cub. When twisting
the Cub trim crank, the stabilizer is being screwed up
and down while the overhead knob in a Champ, which moves
fore and aft in a slot, runs a trim tab on the elevator.
The arrangement is quicker and easier, although, since
it is located over the front pilot's left shoulder in
the ceiling, it's a stretch to reach from the back seat.
To absorb
landing shocks, the Champ uses an oleo-spring
arrangement in the front leg of the landing gear "V"
frame rather than bungees. In speaking with Buzz Wagner
of the International Aeronca Association, he said the
landing gear is the area in which they see the most
problems, mostly because people don't maintain them or
don't understand the system. The system is designed to
use exactly eight and a half ounces of fluid. Let it get
a half an ounce down and the gear will be damaged.
According to Wagner, the majority of Champs in operation
need the landing gear rebuilt to one degree or another
and the difference in ground handling, when all the worn
parts are replaced, is significant.
There were two
different oleo's installed, the original straight oleo,
and the "no bounce" oleo which came out of the
military's desire for an airplane that could be dropped
from ridiculous heights without damage. The original
oleo is less complicated and easier to handle in a
crosswind. Wagner, among others, has new and rebuilt
replacements for either.
All Champs
prior to the 1954 re-introduction of the 7EC used
mechanical brakes. These brakes, if properly adjusted,
work just fine. There are two distinct different types,
the Van Sickle/Cleveland type which is a traditional
drum and shoe set up where a rotating cam actuates them
and the Goodyear which is a form of mechanical disk
brake. In neither one is there no an adjustment to move
the shoes or pads closer to the drums to compensate for
wear, as in a car. This is a weakness in the design and
adjusting the cable tighter (most mechanics' initial
urge) won't help. All that does is rotate the cam closer
to its limits. Wagner says, if shoe brakes are no longer
holding, replace the shoes. In the calliper brakes,
replace the pads, and if they still don't hold, have the
cam built back to its original dimension by welding.
The post-1954
American Champion 7EC's used hydraulic drum brakes which
eliminates most of the problems. Fortunately, none of
the brake types are expensive to rebuild.
The wings are
a combination of wood spars and formed-aluminium ribs.
There is no rib stitching, as with most fabric
airplanes, as the fabric is screwed or pop-riveted to
the ribs. Generally speaking, Champ wings give little or
no trouble.
The wing
struts are welded closed which makes them less
susceptible to rust than some others. Rust, however, is
still a definite concern and they should be carefully
inspected as per FAA guide lines. The end fittings are
welded bushings, not adjustable forks, so there is no
concern in that area.
Flight
Characteristics
It takes about
ten seconds in a Champ's cockpit to decide that all of
Chief Designer Hermes' Anti-Cub design goals were met
and then some. Some argue the Champ cockpit is too
modern. Too civilized. Those are usually Cub pilots
speaking.
Once on board,
the immediate impression will be of visibility and a
cheerful airiness. The wing and skylight is so high and
the pilot sits so far forward, there is none of the "Man
trapped in an airplane" feeling of so many of the
Champ's contemporaries. This is definitely the airplane
for a big person.
One of the
cockpit's niceties is that all of the major engine
controls, i.e. carb heat, fuel on/off, mags are in a
panel by the pilot's left hip. This makes them available
from both seats, although the front seat pilot has to
squirm around a bit to get a hand down there.
Incidentally,
the later airplanes have most of the fuel in the wings
and do away with the fuselage tank, while the original
airplanes have a fuel gage peeking out of the top of the
boot cowl for the fuselage tank.
If it's a 7AC,
you'll be doing the "Brakes! Contact!" routine with an
Armstrong starter. If a 7EC, there's a "T' handled on
the right half of the instrument panel that eases the
starting chores.
In most areas,
there's a big handling difference between the A and E
models because of the difference in weight. An original,
lightly finished A model with its 65 hp Continental
weights about 710-725 pounds or about the same as a Cub.
The 90 hp E models sometimes weigh as much as 200 pounds
more because of electrical, interior, tanks, etc.
There's some
difference of opinion as to how to start a take-off in a
Champ, stick forward or stick back. A lot of the flight
schools that used later 7ECs with the No-Bounce gears
routinely started the takeoff roll with the stick full
forward. Presumably, this was done to get the tail up as
soon as possible to keep the oleos from extending. If
the pilot waits too long to pick the tail up, the weight
will come off the oleos while in a three-point position
allowing them to extend. When they're extended, they
have little to no resistance so they'll compress easily.
When one compresses, even though the airplane is headed
straight, the illusion is that the airplane is turning
and pilots often poke in rudder that's not needed
causing a swerve where there was none. Bear in mind,
however, that all of this is happening in slow motion as
the airplane will fly-off somewhere in the neighbourhood
of 45 mph.
Theoretically,
the bigger engine Champs will climb better than the
lowly 7AC, but not by much. The books say an AC is
supposed to give 500 rpm and the EC 800 rpm. In real
life, the difference isn't that great. Because of its
lighter weight, the 7AC floats off the ground compared
to the 7EC which feels more like it's on rails. Only the
very lightest 7AC, however, has the feather-like feeling
of a Cub when it separates.
Most of the
Cub's resemblance to a feather is probably because the
Cub has just enough more wing area that its wing loading
at gross is a little lower, 6.8 lb/sq. ft to 7.1 lb/sq.
ft. The books say a 7EC weighs 890 pounds empty (1450
pounds gross, more than a C-140) compared to a 7AC at
710 pounds (1220 pounds gross, about the same as a Cub).
Note that the
7EC, despite its much bigger engine has about the same
useful load as the 7AC.
Once up to
cruising speed, the 7AC (65 hp) can generally be
depended on to be 5-8 mph faster than the similarly
powered Cub, or a good solid 85-90 mph. The 7ECs seem to
run about 90-95 mph.
Ask any who
fly a Champ and they'll all say its a "...rudder
airplane...". That's because its adverse yaw is so
pronounced, you either coordinate with rudder or slip
and slide around on the seat. It's much more noticeable
than in a Cub. This makes it a superb trainer.
When you start
trying to compare things like roll rate and aileron
pressures between airplanes like Cubs and Champs, you're
dealing more with perceptions than actual differences.
For one thing, the Cub control stick juts up higher,
especially in the front seat, and has an innately
"bigger" feel to it. The mechanical advantage means the
stick moves further than a Champ's in the same
situation, but the response is probably close to being
the same. The pressures, also, are close, but it is very
difficult to say. The perception is that Cub controls
are heavier, when they really aren't.
There is,
however, a difference to the overall "feel" of the
controls. Somehow, a Cub feels a little more precise and
a touch quicker. We're splitting some very slow-speed
hairs at this point, but that seems to be the general
opinion.
Compared to a
C-152, the roll performance will seem leisurely at best.
The pressures are slightly lighter than a Citabria and
the roll rate about the same.
The Champ
stalls normally, with just a tiny bit of edge to it.
Release the stick and it's flying again. Kick a rudder
hard and it rotates into a surprisingly comfortable spin
that stops as soon as you release back pressure and
punch a rudder. Just letting go will bring it out almost
as quickly as doing something deliberate.
Depending on
the model, a Champ is happy to approach at just about
any speed, but keeping it under 60 cuts down the float.
Three-point landings happen almost automatically once
you get used to a nose that's not in the way. The sight
picture isn't that much different than landing a C-152
on its mains and holding the nose off. Actually, you can
probably see more out of the Champ.
In a no-wind
situation, the airplane will track perfectly straight.
Given a good cross wind, the pilot will have to work a
little harder but the airplane will handle it as long as
the pilot keeps the wing down and the nose straight.
Wheel landings
are also automatic and probably easier than in any other
type of taildragger. Just don't force it on. Let it find
the ground, pin it in place and the landing is over.
The
controversy between those who love the Cub and those who
swear by the Champ will never be resolved. The important
thing to remember is they are both terrific airplanes
and the Champ wouldn't have survived as long as it has
if it hadn't had the Cub as a role model.
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