Whisper X350 Generation II
{{Use dmy dates|date=May 2020}}
{{Use South African English|date=May 2020}}
{{short description|South African kit aircraft design}}
| {{Infobox Aircraft Begin
| name=X350 Generation II | image= | caption= }}{{Infobox Aircraft Type | type=Amateur-built aircraft | national origin=South Africa | manufacturer=Whisper Aircraft | designer= | first flight= | introduced= | retired= | status=In production (2020) | primary user= | more users= | produced= | number built= | program cost= | unit cost= US$55,000 (unassembled kit, 2019) | developed from= Whisper Aircraft Whisper | variants with their own articles= }} |
The Whisper X350 Generation II is a South African amateur-built aircraft, designed in 2015 and produced by Whisper Aircraft of Mossel Bay. The aircraft was developed from the 2004-designed Whisper Aircraft Whisper motorglider. The X350 Generation II is supplied as a kit for amateur construction.{{cite web|url = https://www.avweb.com/features/kitplanes-flight-review-whisper-x350-gen-ii/|title = Kitplanes Flight Review: Whisper X350|access-date = 13 May 2020|last = Cook|first = LeRoy|work = Kitplanes|date = 12 May 2020|archiveurl = https://web.archive.org/web/20200513141104/https://www.avweb.com/features/kitplanes-flight-review-whisper-x350-gen-ii/|archivedate =13 May 2020|url-status= live}}{{cite web|url = https://www.whisperaircraft.com/index.html|title = X350 Gen II|access-date = 13 May 2020|author=Whisper Aircraft |work = whisperaircraft.com|year=2019|archiveurl = https://archive.today/20200519213548/https://www.whisperaircraft.com/index.html|archivedate = 19 May 2020|url-status= live}}
The X350 Generation II designation indicates a design top speed goal of {{convert|350|km/h|kn|0|abbr=on}}, with the larger engine fitted.
Design and development
The aircraft features a cantilever low-wing, a two-seats-in-side-by-side configuration enclosed cockpit that is {{convert|47.2|in|cm|1|abbr=on}} wide, under an acrylic plastic articulated lift-up bubble canopy. It has fixed optionally tricycle landing gear or conventional landing gear and a single engine in tractor configuration.
The aircraft is predominately made from vacuum-bagged, post-cured carbon fibre composites, with E-glass used for non-structural parts, including the engine cowling, aircraft fairings, wing and tail tips. The structure is 10% anodized aluminum and cadmium-plated steel, with the landing gear legs made from steel.
The design's {{convert|26.17|ft|m|1|abbr=on}} span wing has an area of {{convert|122|sqft|m2|abbr=on}} and mounts plain flaps and features a cruciform tail. The aircraft's recommended engine power range is {{convert|160|to|200|hp|kW|0|abbr=on}} and standard engines used include the {{convert|160|hp|kW|0|abbr=on}} Lycoming O-320, the {{convert|180|hp|kW|0|abbr=on}} Lycoming O-360, the {{convert|200|hp|kW|0|abbr=on}} Lycoming IO-390, or the {{convert|180|to|200|hp|kW|0|abbr=on}} ULPower UL520i four-stroke powerplants.
The fuel capacity is {{convert|32|u.s.gal}} in two fuselage tanks, although future production kits will have {{convert|63|u.s.gal}} in a wet wing.
The design has a single centre console-mounted side-stick or optional individual centre stick controls. The ailerons are actuated via push rods, while the elevator has push rods to the tailcone and then cables. The rudder is cable-actuated. There is no elevator trim tab system, but it may be included as a future factory option. Evaluation flights indicated neutral longitudinal stability, however, reducing the need for one. The left seat is equipped with toe-brakes.
The 51% compliant kit includes a mated fuselage and pre-closed wing structures. The aircraft can be constructed in a two-car garage. Construction time from the supplied kit is estimated by the manufacturer as 500 hours.
The design as load factors of +6/-4 g, but is not designed for aerobatics. The instrument panel is made from aluminum. The seats and rudder pedals are independently adjustable. There are optional rear fuselage windows for improved visibility, LED navigation lights and strobe lights on the wing tips and tail. Lightning protection is a factory option.
Operational history
By May 2020 one example had been registered in the United States with the Federal Aviation Administration.{{cite web|url = https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=181WA|title = Make / Model Inquiry Results|accessdate = 13 May 2020|author = Federal Aviation Administration|date = 13 May 2020}}
In a 2020 review, Kitplanes writer LeRoy Cook stated, "the Whisper is a sharp-looking side-by-side two-seater, particularly when perched on tailwheel landing gear. Tricycle gear will probably be a popular option, out of necessity for tamer handling and greater tolerance of gusty winds." Cook noted from his evaluation flight, "from my brief sampling, I’d like to see a little more cockpit ventilation, more foot room after the wing fuel system is installed, and enhanced stability with an elevator trim system. I’d also like to revisit it with tricycle gear." He concluded, "there’s a lot to like about the Whisper X350 Gen II: its sleek looks, the blazing cruise speed, a roomy cockpit, and an apparent ease of assembly."
Specifications (X350 Gen II)
{{Aircraft specs
|ref=Kitplanes and manufacturer
|prime units?=met
|genhide=
|crew=one
|capacity=one passenger
|length m=
|length ft=22
|length in=6
|length note=
|span m=
|span ft=26
|span in=2
|span note=
|height m=
|height ft=
|height in=
|height note=
|wing area sqm=
|wing area sqft=122
|wing area note=
|aspect ratio=
|airfoil=
|empty weight kg=
|empty weight lb=1213
|empty weight note=(typical)
|gross weight kg=
|gross weight lb=2138
|gross weight note=
|fuel capacity={{convert|63|u.s.gal}} in three fuselage tanks
|more general=
|eng1 number=1
|eng1 name=Lycoming O-360
|eng1 type=four-cylinder, air-cooled, four-stroke, horizontally-opposed, piston aircraft engine
|eng1 kw=
|eng1 hp=180
|prop blade number=2
|prop name=Whirl Wind Propellers GA 220L, ground adjustable
|prop dia m=
|prop dia ft=
|prop dia in=
|prop note=
|perfhide=
|max speed kmh=
|max speed mph=
|max speed kts=184
|max speed note=
|cruise speed kmh=
|cruise speed mph=
|cruise speed kts=175
|cruise speed note=at 75% power
|stall speed kmh=
|stall speed mph=
|stall speed kts=52
|stall speed note=flaps down
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|range km=
|range miles=1137
|range nmi=
|range note=
|endurance=6.6 hours
|ceiling m=
|ceiling ft=25500
|ceiling note=
|g limits=+6/-4
|roll rate=
|glide ratio=
|climb rate ms=
|climb rate ftmin=1540
|climb rate note=
|time to altitude=
|sink rate ms=
|sink rate ftmin=
|sink rate note=
|lift to drag=
|wing loading kg/m2=
|wing loading lb/sqft=17.67
|wing loading note=
|power/mass=
|thrust/weight=
|more performance=
|avionics=
}}
References
{{reflist}}
External links
- {{Official website|https://www.whisperaircraft.com/index.html}}