Hipp’s Superbirds J-3 Kitten

The J3 Kitten (designed by Jessie Anglin) is exactly what its name suggests: an adorable “kitten” that shares all the DNA of a classic aviation lion.

It is a reduced-scale replica of the most famous plane in history, but designed specifically for the world of ultralights. Its philosophy is not just to evoke nostalgia, but to offer that pure flight experience in a package that fits the lightest legal regulations and can be moved with one hand on the tarmac.

Here are its advantages, focused on its extreme lightness, its sporty agility, and its ability to evolve with modern engines.

1. Smart Hybrid Construction

The Kitten combines the best of two worlds to keep weight low without sacrificing safety.

• Steel Fuselage: It uses a welded 4130 steel tube fuselage. This gives it rigidity and pilot protection (a “safety cage”) that bolted aluminum tube planes rarely match.

• Lightweight Wings: The wings are usually built with aluminum spars and foam or wood ribs, covered with light fabric. This combination saves critical pounds, allowing the plane to stay within the weight limits of the strictest regulations.

• Plan Simplicity: It is a plane built from plans. There are no complex molded parts or weird extrusions. It is “cut, bend, and weld” engineering.

2. Agility and “Sport Flying”

Despite its vintage appearance, the Kitten flies with surprising energy.

• Power-to-Weight Ratio: Being so light, it doesn’t need a giant engine to move freely. The plane doesn’t just climb; it jumps off the ground.

• Control Response: It is known for being sensitive and agile. While large vintage planes feel heavy and slow, the Kitten feels like a small sports car. It responds instantly to your fingers and feet.

• The Fun Factor: It is a plane designed to fly low and slow, with the door open (or no door), enjoying every gust of wind. It is the definition of “recreational flying.”

3. Power: The Revolution of Modern Engines

Originally designed for the 2-stroke engines of the 80s, the Kitten has benefited greatly from current technology.

• The Classic Option (Rotax): It still works wonderfully with traditional Rotax 2-strokes (447/503), which are cheap and light.

• The Modern Update: This is where the plane levels up. Many builders now install high-power modern paramotor engines (like Polini Thor or Simonini) or light industrial 4-stroke engines (V-Twin type Vanguard or modified Honda).

• Modernization Advantages: By using these modern engines, you get ridiculously low fuel consumption, far superior reliability, and less vibration. Furthermore, these current engines offer a brutal power-to-weight ratio, allowing the Kitten to climb like a rocket without adding extra weight to the nose.

4. Statistics and Performance Numbers

The Kitten is a master of slow flight and short fields, and with a modern engine, these figures improve notably.

Dimensions and Weights:

• Wingspan: 9.14 meters (30 feet).

• Empty Weight: If built carefully, it can weigh as little as 110-115 kg (240-254 lbs).

• Maximum Takeoff Weight (MTOW): Around 227-250 kg (500-550 lbs).

Performance (optimized with a modern 40-50 HP engine):

• Cruise Speed: About 95-105 km/h (60-65 mph).

• Stall Speed: Ridiculously low, 38-42 km/h (24-26 mph). Landing is almost like stopping a bicycle.

• Takeoff Distance: It takes off in a breath. It needs barely 30 to 50 meters (100-165 feet) to get airborne. With a high-torque modern engine, takeoff is almost immediate.

• Rate of Climb: Very respectable, often exceeding 300 meters per minute (1,000 fpm) thanks to its low weight.

Considerations (The reality of the ultralight)

• Wind Sensitivity: Being so extremely light, wind affects it a lot. It is not a plane for stormy days or strong crosswinds; it is a machine for calm mornings.

• Interior Space: It is a “Kitten” for a reason. The cockpit is tight. It is cozy, but space is not abundant.

• Engine Choice: If you go the modern route, you will have to adapt the mount and installation yourself, since the original plans contemplated older engines, but the result in performance is totally worth it.

In summary, the J3 Kitten is the perfect option for the pilot who wants the classic aesthetic with current performance. It is agile, cheap to build, and if you give it a modern heart, you will have a plane that sips fuel like a lighter but climbs like a tiger.