1996: 108 Jefferson Ave, Des Moines. IA, USA.
LSA builder
1996: 108 Jefferson Ave, Des Moines. IA, USA.
LSA builder
1998:
Via Ajaccio 14
I-00198 Roma
Italy
LSA builder

The full sized aeroplane is 16′ x 16′.

The 24 Bis (that’s what they call the example you see in the images) is a tribute to Alberto Santos Dumont.
The Winchester Skonkwerks Ultralight Research and Development Facility —shortened to Skonkwerks — represents a team from Larsen, Wisconsin. Skonkwerks honored Alberto by first building a 23 Bis and later the 24 Bis. The group describes itself as a “loosely knit organization of friends, flyers, and fanatics… tinkerers, builders, and bullsh###rs. We are engineers, designers, and dreamers hanging out in a little hangar screwing stuff together and making it fly.”

Lee Fischer was the founder of this group of tinkerers that formed after he first showed a highly modified Robertson B1-RD. So much interest was shown in the Demoiselle style of aircraft that he decided to build a 23 Bis. At AirVenture 2015, his friend Mark Solper hinted that it would be “great project to build a pair of ‘evolved’ Demoiselles for a subsequent AirVenture.” This suggestion led to the 24 Bis.
Mark, Lee, and the whole merry band machined and welded the airframe and sewed Dacron wings, all the while learning both new skills and an appreciation for what Santos Dumont and his associates had done more than a hundred years earlier.
The aircraft was flown into Oshkosh.

Weight — 240 pounds
Wing Span — 32 feet
Wing Area — 192 square feet
Never Exceed Speed — 45-50 mph
Stall Speed — 14-16
Engine — Rotax 447
Build Time — December 21, 2014 through June 21, 2015

The Winchester Skonkwerks Ultralight Research and Development Facility — let’s shorten that to Skonkwerks — represents a team from Larsen, Wisconsin. Skonkwerks honored Alberto Santos Dumont by first building a 23 Bis and later the 24 Bis. The group describes itself as a “loosely knit organization of friends, flyers, and fanatics… tinkerers, builders, and bullsh###rs. We are engineers, designers, and dreamers hanging out in a little hangar screwing stuff together and making it fly.”
Lee Fischer was the founder of this group of tinkerers that formed after he first showed a highly modified Robertson B1-RD. So much interest was shown in the Demoiselle style of aircraft that he decided to build a 23 Bis. At AirVenture 2015, his friend Mark Solper hinted that it would be “great project to build a pair of ‘evolved’ Demoiselles for a subsequent AirVenture.” This suggestion led to the 24 Bis
Weight: 240#
Wing Span: 32′
Length: 19′
Wing Area @ Chord: 176 sq. ft.
Wing Area @ Camber: 192 sq. ft.
Wing Construction: Tube and Sewn Dacron
The original spelling is currently being used in Winchester Township Wi. Where a hanger was dubbed “The Skonkworks” by a neighbor in the early years. Used by a loosely knit informal organization of like-minded engineers/designers/tinkerers/builders/neighbors and fliers known as the “Lone Buzzerds” an ultralight club, operating out of the “Winchester Skonkworks” or sometimes “Squirrelworks” hanger in Larsen, Wi.
To avoid copyright infringement “Kelly Johnson’s” serious looking “skunk” was changed to a comical, whimsical black and white squirrel looking mascot wearing a red crash helmet and giving a smiling “thumbs up.”
The designation “skunk works”, or “skunkworks”, is widely used in business, engineering, and technical fields to describe a group within an organization given a high degree of autonomy, unhampered by bureaucracy; tasked with working on advanced or secret projects. In this case the spelling “Skonkworks” but in most cases; “Skonkwerks” is being used in jest to project an aura of something outside of the norm being worked on, developed or flown; while staying in touch with meager roots. The term fits well within the ultralight community as there is no direct oversight by any government organization, in addition ultralighters generally operate at the bottom of the aviation financial food chain. Not unlike “Li’lAbner” making “moonshine” from an odd variety of items, or whatever they had on hand.

The SD-27 Corriedale two-seat touring and training lightplane was offered for sale since 1998 (first flown 1992).
Engine: Rotax 912, 80 hp
Seats: 2

Bert Sisler, of Barnsville, Minnesots, second design was the mid-wing Whistler. The two-seat craft is convertible from tailwheel to tri-gear configuration. The fuselage is tubular steel and fabric, the wings and tail are of wood geodetic construction with fabric covering. The baggage compartment has a 70 lb capacity.

The SF-2 Whistler N5549 built in 1973 was improved to become the SF-2A Cygnet circa 1977.
Designed by Burt Sisler, USA, the two-place, plans-built, VW powered Cygnet has geodesic wing construction, offers excellent short-field performance, good climb rate and ease of control. It can handle two 175-pound people and 80 lbs of baggage. This is a United States designed side by side 2 seater being designed for STOL operations. The Cygnet features folding wings and is designed for running on Mogas. Early United States mac¬hines were powered by a 60 hp HAPI engine, providing a 100 mph cruise and 350 mile range.
The Cygnet Model SF-2A in 2008 was available from:
Viking Aircraft
333 Sunny Hill Dr
Elkhorn, Wisconsin 55312
SF-2 Whistler
Engine: 70 hp Baker VW1834
Wingspan: 30’0″
Length: 19 ft
Height: 5 ft 9.5 in
Empty weight: 645 lb
Useful load: 500 lb
Baggage capacity: 70 lb
Max speed: 95 mph
Cruise: 86 mph
Stall: 43 mph
Landing speed: 42 mph
Landing roll: 300 ft
ROC solo: 700 fpm
Seats: 2
SF-2A Cygnet
N191S
Engine: 62hp Barker-VW 1834cc
Wingspan: 30’0″
Length: 19’0″
Useful load: 515 lb
Max speed: 108 mph
Cruise: 100 mph
Stall: 48 mph
Seats: 2
SF-2A Cygnet
Engine: 1835cc HAPI VW conversion
HP range: 60-82
Speed max: 108 mph
Cruise: 90-100 mph
Range: 390 sm
Stall: 41 mph (solo), 48 mph (dual)
ROC: 580 fpm
Take-off dist: 700 ft
Landing dist: 700 ft
Fuel cap: 15 USG
Weight empty: 585 lbs
Gross: 1100 lbs
Height: 5.83 ft
Length: 19 ft
Wing span: 30 ft
Wing area: 125 sq.ft
Seats: 2
Landing gear: tail wheel
Cygnet SF-2A
Engine: 1835 60HP VW
Span: 30 ft
Empty Weight: 585 lbs
Useful Load: 515 lbs
Seats: 2 Side by Side
Stall: 48 mph
Landing Speed: 60 mph
Cruise: 100 mph
Rate of Climb: 580 fpm
Built during the 1970s, the two seat Sisler SF-1 Pipit was sold before the formation of the Sisler Aircraft Co.
(A M Bert) Sisler Aircraft Co,
Bloomington MN.
USA
Airline captain Bert Sisler built and sold Pipit 2-seater, formed Sisler Aircraft Co. and built SF-2 Whistler (EAA award 1973) and later marketed plans for improved version SF-2A Cygnet high-wing 2-seater.