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Technical information






Engine Mount

Gear Configuration

G Loading

Roll Rate


Typical Cost Including Build

*Typical Cost Incl. engine, avionics and propeller, see "PRICING" for more details.

Typical Build Time




Overall Length



Internal Cabin Width




Gross Weight

Empty Weight

Typical Useful Load

-Max Fuel Load

-Useful Load Max Fuel


Lycoming / UL Power

180 hp / 200 hp / 210 hp

Dynafocal / Conical

Tail Wheel / Nose Wheel

+ 6.0, - 4.0

110 deg/sec


US$92,000 / ZAR1,300,000


550 hours




22 ft 6 in / 6.30 m

6 ft 2 in / 1.9 m

26 ft 2 in / 8.00 m

47.2 in / 1,193 mm




2,138 lbs / 970 kg

1,213 lbs / 550 kg

925 lbs / 420 kg

388 lbs / 176 kg

538 lbs / 244kg


Fuel Consumption (1,500ft)


85  kts

106 kts

115 kts

120 kts

136 kts

155 kts - 55% Cruise   

160 kts

176 kts

180 kts





6.16 USG/hr - 23.3 liters/hr

5.10 USG/hr - 19.3 liters/hr

4.76 USG/hr - 18.0 liters/hr

5.46 USG/hr - 20.7 liters/hr

6.87 USG/hr - 26.0 liters/hr

8.61 USG/hr - 32.6 liters/hr

9.80 USG/hr - 37.1 liters/hr

10.38 USG/hr - 39.3 liters/hr

11.15 USG/hr - 42.2 liters/hr





Fuel Capacity

Fuel Consumption ( 55% Cruise, typ)

Fuel Type


Performance at Sea Level (1,500ft)

Lycoming O-360 180HP, 2-Blade Whirlwind GA 200L Propeller.


Top Speed (typ)

Cruise Speed - Sport (typ 75%+ Power)

Cruise Speed - Economy  (typ 55% Power)

Stall Speed

Take Off Ground Roll

Landing Distance

Rate of Climb

Max Operating Altitude

Range (Incl. Reserve, Taxi, Takeoff)

Endurance (Incl. Reserve, Taxi, Takeoff )

63 USG / 240 liters

8.5 USG/hr / 32.17 liters/hr






184 kts / 211 mph / 340 km/h

175 kts / 201 mph / 323 km/h

155 kts / 178 mph / 287 km/h

52 kts / 60 mph / 96 km/h

630ft / 192m

656ft / 200m

1,540 ft/min / 7.82 m/s

25,500 ft / 6,858 m

‪1,137 miles / 1,850 km

6:38 Hours

Download Additional Technical Information

Compare to Other Aircraft

Download Build Manuals

The X350 Gen II is a two seat, cross-country sport aircraft, with a limit load factor of plus 6.0 and minus 4.0g’s.


The wings feature a carbon fiber structure tested to an ultimate load factor of 12.0 g’s. The Gen II’s wing tanks have a total fuel capacity of 63 US gallons, giving a range of 1,000 nautical miles and an endurance of over 6 hours.


The aircraft also has one of the widest interiors on the market today,  featuring leather interior (Optional) and plenty of baggage room making the Gen II perfect for comfortable cross-country trips.


Typical Useful Load - 925lbs / 420kg  |  175kts  |  Range - 1,137miles / 1,830km


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The X350 kit can be completed in +-500 hours depending on your current skill set, when you receive your kit all structural parts and large surfaces will be completed. The kit ships with a base coat already sprayed to insure product quality, and ultimately the finished aircraft quality. The kit ships with 90% built Wings, Horizontal Stab, Rudder, Flaps, Ailerons, Elevators and Fuselage. Within a short time your aircraft will be ready for motor installation.

Building any kit aircraft  is complicated, so it's important to have proper literature and illustrations to carry across what is to be built and completed and in what order. This makes a complicated project less complicated and understandable,  thus making the "build" easy and faster. It was therefor essential for us to meet this criteria and properly illustrate to the builder so to have the builder be well informed and to also get across why a certain technique is used and how to use the techniques correctly.



Want to know more about composite? Check out the X350 Build Manual Chapter 1 - Introduction, to find out more about the materials used in the Gen II.

Available CAD Drawings


All assemblies in the aircraft can be reproduced by the builder using provided CAD drawings should it be required.



Color Illustrated Exploded Views


The build manual features color "exploded" views of all assemblies located in the Gen II.



Few Composite Layups


No need to worry about extensive layups, quick, simple, clean.





Primed and ready to go, all composite parts is pre primed so to minimize body work done by the builder, saving crucial time and funds.



Build at Home, Trailer to Hangar


Build your Gen II in your garage, when completed, trailer your aircraft to your hangar and finish her off.



Build Assist Program


Customizable builder assist at your facility. First to build in your region? We'll cover half the builder assistance costs!


Download a sample build manual.

Download Build Manuals


The X350 has been designed with the pilot in mind, sounds cliché right? Well its true, from small things such as wheel spats that have access to inflate the tires, stowage space in the cockpit to keep all items tidy on a busy flight, and various pilot and passenger safety elements. All these features result from the X350 aircraft design, while at the same time allowing a build time of approximately 500 hrs (can built in a two car garage) and meets the FAA 51% rule.


Key Design Features:


Passive Safety Elements  | Computer Aided Finite Element Analysis | Built and Tested to Certified Aircraft Standards (FAR 23).

All Composite Airframe


Composite carbon fiber construction, vacuum bagged for lightness, then post cured for stiffness and strength. Carbon fiber main spars and spar-box for extreme G-loading conditions.



Corrosion Resistance


Composites do not corrode. Any aircraft owner close to the coast will caution you to the horrors of corrosion on metal aircraft and metal parts, the X350 has no such issues as 95% of the aircraft is built using composite.



Large Aluminum Avionics Panel


The large avionics panel supports up to 11" EFIS screens and a traditional radio stack.



Adjustable rudder pedals


Adjust your rudder pedal independently for maximum comfort.



Independently Adjustable Seats


Adjustable semi-reclined seats, offering a wider range of comfort.



Large Canopy


The large acrylic canopy allows for spectacular views from within the aircraft throughout your journey. The large canopy also has a unique rearward tilt opening mechanism to allow for easy ingress or egress.



Canopy Air System


The canopy has fresh air integrated into its frame so to allow hot or cool air to the canopy glass and crew, perfect for those hot, or cool days.



Engine Cooling Plenum


No complicated air baffling required. The plenum allows for easy access to the spark-plugs and keeps the engine at optimum operational temperature.



Large Storage Bay


The two seats fold forward so to easily load up to two golf bags, your fishing rods and camping equipment all with ease.




Long Range Fuel Tanks


The X350 Gen II sports two large wing tanks with a combined 63USG / 240 liters worth of fuel and with a range of 1,180 miles / 1,900 km or fuel what you need and increase your useful load more,




500 Hours Build Time


The X350 kit can be completed in +-500 hours depending on your current skill set, when you receive your kit all structural parts and large surfaces will be completed, the kit ships with a base coat already sprayed to insure product quality and ultimately the finished aircrafts quality.

Trailer-able Within Minutes


Easily removable horizontal stabilizer, and wings. Have your aircraft ready to be trailered or stored  within 15 minutes.



Cockpit Stowing Space


Over 200l worth of stowage space, space for books, iPads, cellphones, pens, keys, and anything else you can fit, finally cleaning up the copilots seat or lap from clutter.



Tri-Gear or Tail Dragger





Internally Balanced


All control surfaces are internally balanced, leaving no exposed elevator leading edges vulnerable to small stone damage and paint chips.



Rear Windows


Optional rear windows for increased visibility.



No Rivets


Smooth skin for pearlescent paint or vinyl wrap to express your artistic side or advertise your company.





Few aircraft can be as easily customized as the Gen II, with many options ranging from landing lights, seat changes, full interior modifications, cowl modifications. Factory support is available for these types of changes, so your X350 is built just as you want it.






Structures are easily repaired; composite has a straightforward procedure to

repair almost any and all damage quickly, easily and safely. Factory support is available for replacement of large structural parts.



Wide Cockpit


One of the widest 2 place aircraft cockpits available on the market today.

Internal Cabin Width - 47.2 in / 1,200 mm


Wide CG Range


A wide center of gravity range (9.1" to 17.6") means easier loading for those long trips and offers the builder more latitude in engine and propeller weights.



Custom Engine Support


As engine technology evolve we constantly see new engines come to the market. Whisper and our design team are dedicated to assist a builder and offers full factory support should the builder be willing to install a new engine into their X350 Gen II.



Whisper Aircraft is committed to safety, it is for this reason that we design, build and test to high standards, from the type of fuel senders we use to the type of composites and resin system.

Unfortunately, not all accidents can be avoided. Passive Safety features help minimize the probability and degree of injuries.



Passive safety elements include:


Structural integrity of the cabin under crash-loads | Effective occupant restraint | Unobstructed Head Strike Zones | Stainless Steel Braided Fuel Lines


The best accident protection is to avoid them in the first place.



Very High Ultimate Wing and Airframe Strength


The Gen II wings and empennage have been tested to FAR 23 (Aerobatics) standards. The Gen II have a ultimate G loading of 12 G's and a limit load of 6G's.



Magnetic Field Fuel Senders


CiES Fuel Level Senders, Only the best in fuel sensing technology, know exactly what your fuel level is accurately.



Lightning Strike Protection - Optional


The Gen II has a optional lightning protection layer to aid lightning to pass through the aircraft and continue to the ground.



AN Hardware


The Gen II only uses the best quality hardware throughout the aircraft. Why settle for something else only to save a few bucks?



Effortless Inspection


Easily inspect all major control assemblies without opening any covers.



Designed, Tested


From full 3D CAD modeling, FEA testing on structural components, and physical testing; all conducted under strict guidance of FAR 23.


Survivable accidents should be exactly that – survived.





Ballistic Chute Ready




Stainless Steel Braided Fuel Lines


Whisper takes special measures to minimize the probability of post-crash fires. Aluminum fuel lines typically used in many other aircraft, rupture easily in a crash when supporting structures are deformed. To help prevent this, we use tough and flexible stainless steel braided high-pressure fuel lines that move with the deforming structure and have a vastly superior strength and rupture resistance.



Fire Retardant Cowling


Increased protection for an unexpected engine fire.



Robust Gear


Landing Gear has been designed and drop tested according to strict FAR 23.725 standards.





12.0g, 11,023lbs (5,000kg) “Ultimate Load” Test (Factor of Safety 2.0 for Limit Load of 6.0g)

 © D Michie 2019

From Top Left -  3D Render of Complete Aircraft Assembly with Cowl Open, Finite Element Analysis (FEA) of Main Spar, 3D Render of Complete Aircraft Assembly with Wing Exposed, Computer Aided Optimization of Avionics Panel and Center Console, Engine Cooling Plenum,  Surface Plot with Overlaid Flow Trajectories

*Picture illustrates a standard quick build kit, note each kit differ slightly due to customer features and requests.

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Comparing aircraft is a crucial step, before purchasing your dream aircraft, this is why we present the comparisons here, for your convenience.


Shown aircraft is the most popular aircraft from the United States, Europe and South Africa, similarly they fall into the same price category and for the most part have similar performance. All these aircraft is also presented as kits.


While comparing the various aircraft keep what has been learned about the X350 Gen II in mind.





Still Not Convinced?

Download the Kit Aircraft Score Sheet.

General                              X350 Gen II


Seats                                                     2

Engine                                                  Lycoming

Horsepower                                        180 hp


Typical Cost Including Build           $92,000+  / R1,300,000+

Typical Build Time                             550 hrs


Wing Loading                                    17.50 lb/sq ft

Power Loading                                   11.88 lb/hp

G Loading                                            +6.0, -4.0 @ Gross


Tail Dragger Option                          Yes

Construction                                       Composite





Overall Length                                   22 ft 6 in / 6.30 m

Height                                                  6 ft 2 in / 1.9 m

Wingspan                                            26 ft 2 in / 8.00 m

Internal Cabin Width                       47.2 in / 1,200 mm




Gross Weight                                      2,138 lbs / 970 kg

Empty Weight                                    1,213 lbs / 550 kg

Useful Load                                         926 lbs / 420 kg

-Max Fuel Load                                  388 lbs / 176 kg

-Useful Load Max Fuel                     538 lbs / 244 kg




Fuel Capacity                                      63 USG / 240 liters

Fuel Consumption @ 55% Cruise    8.5USG /hr, 32.17 L/hr

Fuel Type                                              AVGAS





Cruise speed 75% Power                 175 kts / 323 km/h @1500ft

Cruise speed 55% Power                 155 kts /  287 km/h @1500ft

Stall Speed                                          52 kts / 96 km/h

Take Off Ground Roll                        630ft / 192 m

Landing Distance                              656 ft / 200m

Rate of Climb                                      1,540 ft/min / 7.82 m/s

Max Operating Altitude *                25,500 ft / 6,858 m

Range (with reserves)                      1,137 miles / 1,830 km @55%






180 hp


$85,000+ / R1,709,000+

1200 hrs


14.8 lb/sq ft

10.00 lb/hp

+6.0, -4.0








20 ft 4 in / 6.22 m

7 ft 10 in / 2.16 m

25 ft  / 7.62 m

43 in / 1,092 mm




1,800 lbs / 816 kg

1130 lbs / 512 kg

670lbs / 304 kg

253 lbs / 115 kg

417 lbs / 189 kg




42 USG / 159 liters







171 kts / 317 km/h @8000ft

154 kts /  285 km/h

50 kts / 93 km/h

575 ft / 175 m

500 ft / 152 m

1,600 ft/min / 8.13 m/s

19,500 ft / 5,944 m

940 miles / 1,513 km






210 hp


$98,000+ / R1,840,000+

1200 hrs


16.25 lb/sq ft

9.76 lb/hp

+6.0, - 3.0 @ 1900lbs








21 ft 1 in / 6.43 m

8 ft 2 in / 2.5 m

27 ft / 8.00 m

46.0 in / 1,168 mm




2050 lbs / 930 kg

1,240 lbs / 563 kg

810 lbs / 367 kg

300 lbs / 136 kg

510 lbs / 231 kg




50 USG / 189 liters







168 kts / 311 km/h @8000ft

147 kts / 272 km/h

51 kts / 94km/h

630 ft / 192 m

715 ft / 217 m

1,500 ft/min / 7.62 m/s

18,000+ ft / 5,486 m

1,080 miles / 1,738 km


Lancair Barracuda




310 hp


$230,000+ / R3,500,000+

1120 hrs


23 lb/sq ft

7.0 lb/hp

+4.4, -2.2 (utility)








22 ft / 6.70 m


25 ft 5 in / 7.77 m

43.5 in / 1,105 mm




2,200 lbs / 998 kg

1,450 lbs / 658 kg

750 lbs / 340 kg

360 lbs / 163 kg

390 lbs / 177 kg




65 USG / 246 liters

14 USG/hr / 52 L/hr






223 kts / 413 km/h @12,000ft


52 kts / 96 km/h

800 ft / 244 m

900 ft / 274 m

2,700 ft/min / 13.7 m/s -solo


1,093 miles / 1,759 km


   Sling 2




115 hp


$109,000+ / R1200,000+

850 hrs




+4.4, -2.2 (utility)








21 ft 10 in / 6.67 m

8 ft / 2.45m

30 ft 1 in / 9.17 m

43.8 in / 1,11 mm




1,543 lbs / 700 kg

847 lbs / 384 kg

697 lbs / 316 kg

238 lbs / 108 kg

459 lbs / 208 kg




39.6 USG / 150 liters

3.8 USG/hr, 14.38 L/hr






130 kts / 240 km/h


46 kts / 85 km/h

460 ft / 140 m

295 ft / 90 m

900 ft/min / 4.57 m/s

16,000 ft / 4,876 m

805 miles / 1,296 km @75%



* Above specifications were current when publishing this website, for updated specifications visit above compared aircraft respective websites to verify information. This comparison is shown only for convenience.

* Max Operating Altitude is Max Theoretical Operating Altitude.


Dynamic WT9




100 hp


$‪131,506+ /  R1,900,000+‬

850 hrs




+4.4, -2.2








21 ft / 6.40 m

6.56 ft / 2.00 m

29 ft 52 in / 9.00 m

45.3 in / 1,15 mm




1,323 lbs / 600 kg

595 lbs / 270 kg

728 lbs / 330 kg

198 lbs / 90 kg

529 lbs / 240 kg




33 USG / 125 liters

4.54 USG/hr, 17.2 L/hr






130 kts / 240 km/h

100 kts / 185 km/h

42 kts / 78 km/h



1190 ft/min / 6.05 m/s


767 miles / 1,234km



The pricing shown is intended as a budgeting aid only and is not a guarantee of pricing or availability. Prices are based on the best available information however are subject to change without notice.


Have a friend that might join you in building their own X350? Special pricing for United States and International orders for 2 or more kits.

For a formal quote fill out the form below.

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Whisper X350 Gen II

X350 Gen II is Personalized to Suit Your Taste



Click on the little aircraft for more information.

*Distance and time indicated are for guidance only and should not be used for flight planning purposes. Air traffic, weather and other factors are not taken into consideration. Shown range estimates apply to standard equipped aircraft and can change without notice.



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