Acrolite
The Acrolite was designed as a
good performing entry level aerobatic capable aircraft in a light,
low cost package for those pilots that want a more exciting and
challenging aircraft to fly than the more common type of light and
ultralight aircraft.
Designed by Ron Wilson of Murillo Ontario, it was
the winner of the 1995 Scratch Build Design Contest sponsored by
Aircraft Spruce and Specialty Co. of Fullerton California and hosted
by the Experimental Aircraft Association in Oshkosh Wisconsin. This
design won out over 102 entries from all over the world. Aircraft
Spruce sponsored the cost of building the airframe and the aircraft
was built in one year by Peter Eisenbach of Thunder Bay and Vern
Ennis and Harold Spithoff of Kakabeka Falls Ontario.
It was designed
with strength, ability to take abuse, ease of repair, good short
field performance and stable flight characteristics as the most
important features. The strut braced staggered wing biplane design
affords good visibility and requires a pilot with only average
flying ability but with some experience in high performance taildraggers. The design and basic construction is in accordance
with standard aircraft practices and aircraft grade materials are
used throughout. The aircraft is conservatively stressed for a limit
load of 6 G positive and 4 G negative with a 1.5 safety factor at a
gross weight of 650 lbs.
One of the nice things about small biplanes is
that they can be built in a fairly small area. The largest piece is
the fuselage which is approximately 12 feet long 2 feet wide and 4
feet high. Built on a 12' x 2' table with a minimum of 3 feet of
walk around area it can be built in any 17 foot long room. A single
car garage is more than adequate and the entire aircraft can be
fully assembled in an average 2 car garage. The wing panels are
built standing on edge in a 8 foot long jig.
For the best performance and reliability the
preferred engine is the four cylinder Rotax 912 or 914. The engine
in the prototype is the four cylinder Rotax 912. However the Rotax
582/618 twin cylinder two stroke with a "C" or "E" type gear
reduction drive will give good aerobatic performance at a lower
cost.
The fuselage is constructed of welded 4130 chrome
moly steel tube. A welded steel fuselage is generally considered to
be the most durable, is easy to repair and provides the best
protection against impact damage. Control linkages to the ailerons
and elevator are push-pull rods with bearings on each end. Rudder
and steerable tailwheel control is via a common cable. The tail
assembly is constructed of 6061 aluminium tube riveted together with
2024-T3 aluminium gusset plates.
The wing is of stressed skin wood construction
with a built up box section main spar, built up ribs, plywood
sheeting and fabric covered. The builder will also have the option
of building the wing entirely of 2024-T3 aluminium with a box
section main spar, a channel section rear spar, fully sheeted and
flush riveted with 1/8 inch diameter stainless steel blind rivets.
The airfoil is GA30-212 semi-symmetrical section designed by Harry
Ribblett. This airfoil is noted for its low drag and excellent stall
characteristics. The ailerons are semi-full span aluminium tube,
static balanced. The fuselage, empennage and ailerons are fabric
covered with 1.7 oz PolyFiber fabric.
The landing gear is one piece spring aluminium
clamped and bolted directly to the bottom of the fuselage with four
bolts. This type landing gear has low drag is easy to construct and
handles hard landings and rough ground well. The wheels and tires
are 500 X 5 aircraft type with cable operated drum brakes.
Optionally hydraulic operated disk brakes can also be used. The
tailwheel spring is formed from aluminium flat bar and the tailwheel
swivel unit is welded from chrome moly sheet steel. The 5 inch
diameter tail wheel is moulded hi-impact plastic.
Flying the Acrolite
Aircraft
This airplane is a delight to fly.
Despite the lower range of engine horsepower used, performance is
impressive. The airplane has a three to one speed range (top speed
is three times stall) which is exceptional for a small light
airplane without flaps.
Unlike most small biplanes the Acrolite is a very
easy airplane to fly. Ground handling is excellent and in the air it
is very responsive yet stable. Control feel is light but firm enough
that there is little tendency to over control the aircraft. Stall
occurs at a little less than 45 mph (72.5 kph). straight ahead with
just a little shudder to let you know what has happened. There is no
tendency for it to fall off one wing and the ailerons work right up
through the stall. An intentional spin is almost impossible. The
Acrolite has to be forced into a spin. Recovery is immediate after
releasing the controls. The Acrolite was designed for entry level or
fun aerobatics. Loops, rolls, hammer head turns, Immelman turns and
Cuban eights are no problem with a little practice. This is a very
honest airplane with absolutely no vices in the air or on the
ground. Flying the Acrolite is a real ball, when you move the
controls you are rewarded with a smooth quick response and the
airplane goes precisely where you want it to. It behaves a lot like
a high performance sports car in the air.
While the Acrolite was not intended for cross
country use it performs very well at it. It is rock solid and steady
in cruise and flies straight and level with minimum control
corrections. With the Rotax 912 engine, cruise speed at 5000 rpm is
over 110 mph (177 kph). and the engine burns less than 4 U.S.
gallons (15.4 litres) an hour. With the main tank, range is limited
to about 200 miles(322 kilometres), plenty enough for short cross
country use.
Type: Single Place light
sport biplane, strut braced.
Construction: Welded steel tube
fuselage, riveted aluminium tube tail group, full sheeted box spar
wing.
Engine |
80
hp Rotax 912 |
75
hp Rotax 618 |
65
hp Rotax 582 |
Reduction |
2.43
to 1 |
2.58
to 1 |
2.58
to 1 |
Propeller |
68 x
48 |
66 x
46 |
64 x
44 |
Airfoil |
GA30U-212 |
|
|
Wingspan |
20
ft. x 2 |
|
|
Wing area |
133
sq. ft. |
|
|
Aspect ratio |
9 to
1 |
|
|
Length |
17
ft. |
|
|
Height |
6
ft. |
|
|
Tail length |
10
ft. |
|
|
Fuselage frontal area |
6
sq. ft. |
|
|
Fuselage eff drag area |
2.8
sq. ft. |
|
|
Total eff drag area |
4.4
sq. ft. |
|
|
Horizontal tail area |
19.5
sq. ft. |
|
|
Vertical tail area |
11
sq. ft. |
|
|
Elevator area |
9
sq. ft. |
|
|
Rudder area |
4
sq. ft. |
|
|
Aileron area |
15.5
sq. ft. |
|
|
Horiz. tail volume coef |
.331
|
|
|
Vert.
tail volume coef |
.028
|
|
|
Fuel capacity |
9
gal U.S. |
|
|
Wheel & tire size |
500
X 5 |
|
|
Empty weight |
500
lbs |
480
lbs |
480
lbs |
Gross weight |
800
lbs |
750
lbs |
750
lbs |
Span loading |
20.0
lb./ft |
18.7
lb./ft |
18.7
lb./ft |
Wing loading |
6.0
lb./sq. ft. |
5.6
lb./sq. ft. |
5.6
lb./sq. ft. |
Power loading |
10
lb/bhp |
10
lb/bhp |
11.5
lb/bhp |
Aircraft Performance Specifications
Power off stall speed |
45
mph |
42
mph. |
|
Power on stall speed |
40
mph |
38
mph |
|
Landing speed |
55
mph |
53
mph |
|
Maneuvering speed |
85
mph. |
|
|
Maximum level speed |
130
mph |
125
mph |
110
mph |
Never exceed speed |
150
mph |
|
|
Cruise speed |
@ 5000 rpm 110
mph. |
@ 5600 105 mph. |
90
mph |
Best glide speed |
75
mph |
|
|
Best rate of climb |
1800
fpm |
1900
fpm |
1400
fpm |
Best
climb rate speed |
80
mph |
|
|
Best
climb angle speed |
70
mph. |
|
|
Range |
250
sm. |
|
|
Take off distance |
500
ft. |
|
|
Landing distance |
500
ft. |
|
|
|