The Development of the the SA102.5 Cavalier
& Other Cavalier Models


GY-20 Minicab

The original inspiration for the SA102.5 Cavalier was the GY-20 Minicab.

GY-20 Minicab

GY-20 Minicab owned by Mr Ron Feenaghty

 

The GY-20 Minicab is a small side by side, two seat monoplane originally conceived in France by Yves Gardan. It is constructed of wood with a fabric skin originally powered by a 65HP Continental engine. The prototype first flew in 1949. Eventually, the plans were translated from French to English and made available for amateur builders.

 
 

Cavalier SA102.5

The SA102.5 Cavalier is a much modified and refined development of the GY-20 Minicab. It is in the same French tradition, as the Jodels, the Emeraudes, and other fine wooden aircraft from Europe, but designed in Western Canada by Stan McLeod. The first flight of the prototype SA 102 was made in 1964 and subsequent development (such as the addition of tip tanks) lead to the first flight of the SA 102.5 in February 1971.

 

102.5 Cavalier

 

Basically, a SA102.5 Cavalier is a two-seat (side by side) cantilever low-wing monoplane. The wing section is a NACA 23015 at the root and NACA 23012 at the tip. The wing structure consists of a single wooden box spar, plywood leading edge, and an auxiliary rear spar to carry the flaps and ailerons. The centre section and leading edge of the wing is plywood covered, the remainder covered with fabric. The fuselage is a wooden truss type structure of spruce and birch ply construction. The cockpit doors and canopy are of fibreglass. The rear decking is fabric covered as are the control surfaces. The standard aircraft has a fixed tricycle under-carriage with spring steel gear legs. Fuel is carried in wing tip tanks of up to 22 Imperial gallons capacity. Engine options range from 85 hp to 135 hp.

Specifications with a 125 hp Lycoming O-290 engine :  
 
Span27' 4"
Length22' 0"
Wing Area118 sq.ft
Weight empty900 lb
Weight loaded1,500 lb
Wing loading12.7 lb/sq.ft
Max. speed150 mph
Cruise speed130 mph
Stall speed50 mph
Climb1,000 fpm
Range715 miles
 
 

Some Notes from the Designer - Mr Stan McLeod (April 2004)


SA102, SA102.5, SA 103, SA104 Cavaliers and SA105 Super Cavalier

The Cavalier started life as the SA102 Cavalier and the prototype; built by Forest Fenton of Calgary, flew with 135 hp Lyc in 1963. This was a fairly basic machine by present day standards but was the aircraft that proved the "Rod Nose Gear" could be made to work (others had tried and failed). The original prototype just plain wore out, was rebuilt and I believe still exists. Could use engines from 85 to 135hp, could be built as tri gear or tail dragger and was easily convertible from one to the other.
NOTE: the tail dragger turned out to be around 15 mph SLOWER than the tri gear and didn't handle rough fields any better than the tri gear; however both offered excellent handling on the ground. Some builders demanded retractable gear for the Cavalier and this was not practical so I spent some 4-5000 hrs designing a new airplane with retractable gear - the SA105 Super Cavalier.

SA105 Super Cavalier (1968)

This airplane follows the same basic construction pattern as the SA102.5 but is beefed up to;
1) take larger engines and variable pitch props from 125 to 200 hp, including auto conversions
2) withstand the higher gross weights necessary
3) withstand the higher stresses of the higher cruising speeds
4) enlarged cockpit
    a) to house two people comfortably for long cross country flying
    b) more radios and instruments for x country and IFR flying
    c) provide room for the retracted nose wheel and pilots/pass, legs
    d) added baggage space necessary for x country travel
5) fuselage is 4" wider and 4" taller than the 102.5 and 7" longer
6) wing structure is beefed and modified to accept retractable gear and mechanism
7) tricycle landing gear is all spring steel and manually retracted similar to the early Mooneys. hydraulic retraction can be adapted quite easily
8) streamlined fibreglass tip tanks are added to remove all fuel from the cockpit and increase the aspect ratio and wing area (these tanks produce lift and reduce drag).

SA102.5 Cavalier "1/2- SA102 and 1/2- SA105" (1969-70)

I purchased an almost complete SA102 (which incidently was mostly built in the basement of an hotel in Banff Alberta, by Merton Eldridge who was the accountant in the hotel) and produced the SA102.5 Cavalier prototype.

SA102.5 Cavalier Prototype

SA102.5 Cavalier Prototype


The SA102 is restyled to incorporate;
1) the Tip Tanks from the SA105
2) windows behind the seat
3) various simplifications and construction improvements
4) elimination of the tail dragger option (due to low speed and no better ground handling, or rough field capability)

Styling Revisions (1972);
1) revised landing gear mounting to eliminate/simplify fittings and make legs easier to make
2) revised nose gear mount to allow the aircraft to be moved on it's gear with the engine removed and to simplify the engine mount

Major Styling Revisions (1988);
1) restyled tip tanks
2) flaps changed from split to "simple" type 15,30,45,60 deg.down and -8 to -12 deg. reflex capability for up to 15% higher cruise
3) restyled stabilisor and fin tips
4) "Fighter Canopy" - all new, front hinged, lift up canopy with fibreglass frame - 2 styles to choose from

SA103 & SA104 Cavaliers (1988)

SA103 is a "Fixed, spring steel gear Tail Dragger", aircraft, based on the SA105 airframe
SA104 is a fixed spring steel Tri Gear aircraft based on the SA105 airframe
The SA103 and SA104 can use aircraft or automotive engines from 125 to 200 hp.
All four Cavalier aircraft "appear" very similar and are hard to tell apart visually.

For those interested in building, plans or finding out more about Cavaliers (SA102, SA103, SA104 or SA105 Super Cavaliers),
Stan McLeod's address is:


Box 929
Coleman
Alberta
"Uniquely Western Canada"

Email:   mcleodsk@shaw.ca

Or take a look at the Official Cavalier site:   K & S Aircraft






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