The Sikorsky S-35 was one of the most ambitious aircraft projects of the 1920s. Designed by aviation pioneer Igor Sikorsky, the aircraft was built specifically for an attempt to win the famous Orteig Prize by completing the first nonstop flight from New York to Paris.
Although the Sikorsky S-35 never completed its historic mission, the aircraft remains an important chapter in aviation history. Its advanced engineering, bold design, and tragic crash helped shape future long-range aircraft development and highlighted the risks of early transatlantic aviation.
Sikorsky S-35
What Was the Sikorsky S-35?
The Sikorsky S-35 was a three-engine sesquiplane transport aircraft developed in 1926 by the Sikorsky Manufacturing Company. Originally designed as a twin-engine transport aircraft, it was later redesigned into a trimotor aircraft to improve range and reliability for a transatlantic flight attempt.
The aircraft was commissioned for famous French World War I ace René Fonck, who wanted to become the first aviator to fly nonstop across the Atlantic Ocean from the United States to France.
At the time, the aviation world was obsessed with the Orteig Prize — a $25,000 reward offered to the first pilot who could successfully fly between New York and Paris without stopping.
Sikorsky S-35 Specifications
Here are the key specifications of the Sikorsky S-35 aircraft:
Feature
Details
Aircraft Type
Trimotor sesquiplane
Manufacturer
Sikorsky Manufacturing Company
First Flight
August 23, 1926
Engines
3 × Gnome-Rhône Jupiter 9A radial engines
Engine Power
425 hp each
Landing Gear
Fixed tail-skid with auxiliary jettisonable gear
Construction
All-metal frame with fabric covering
Passenger Capacity
Up to 12 passengers
Purpose
Nonstop transatlantic flight attempt
The S-35 featured an enclosed cockpit, a spacious cabin, and an innovative fuel storage system with tanks located in the wings, fuselage, and engine nacelles.
Innovative Design Features
The Sikorsky S-35 was considered technologically advanced for its era. Several features made it stand out among 1920s aircraft:
1. Triple-Engine Reliability
Long-distance flights over the Atlantic were extremely dangerous in the 1920s. By using three engines, Sikorsky aimed to improve safety and allow the aircraft to continue flying even if one engine failed.
2. Auxiliary Landing Gear
Because the aircraft carried massive fuel loads, engineers added detachable auxiliary landing gear to support the heavy takeoff weight. Once airborne, this extra gear would separate from the aircraft.
3. All-Metal Construction
Unlike many aircraft of the era that relied heavily on wood, the S-35 used duralumin metal construction. This made the aircraft stronger and more suitable for long-distance operations.
4. Large Cabin Space
The aircraft included a roomy interior cabin measuring roughly 15 feet long, designed for passengers or cargo. Historical reports even claimed René Fonck insisted on carrying luxury items such as a sofa and refrigerator during the transatlantic attempt.
Test Flights and Early Promise
The Sikorsky S-35 completed its first successful flight on August 23, 1926, from Roosevelt Field in New York. Several additional test flights demonstrated strong performance, including altitude tests, speed evaluations, and cross-country navigation trials.
Pilots and military observers reportedly praised the aircraft for its stability, maneuverability, and surprisingly light controls despite its large size. According to Sikorsky archives, some pilots compared its handling to that of smaller pursuit aircraft.
The Fatal Transatlantic Attempt
On September 21, 1926, the Sikorsky S-35 attempted its historic flight from Roosevelt Field to Paris. However, the aircraft was heavily overloaded with fuel and equipment. Reports indicated it exceeded safe operating weight by approximately 4,000 pounds.
During takeoff, the auxiliary landing gear detached as planned, but the aircraft failed to gain enough lift. The S-35 ran off the runway, crashed, and burst into flames before ever leaving Long Island.
While René Fonck and co-pilot Lawrence Curtin survived, radio operator Charles Clavier and mechanic Jacob Islamoff lost their lives in the accident. The disaster shocked the aviation world and temporarily halted Fonck’s transatlantic ambitions.
Why the Sikorsky S-35 Matters in Aviation History
Even though the aircraft failed in its primary mission, the Sikorsky S-35 played an important role in aviation development.
Lessons in Long-Range Flight
The crash highlighted the dangers of excessive aircraft weight and the limitations of aviation technology during the 1920s. These lessons influenced future aircraft engineering and flight planning.
Contribution to Sikorsky’s Legacy
The project strengthened Igor Sikorsky’s reputation as an innovative designer willing to push aviation boundaries. Sikorsky later became one of the world’s most influential aircraft engineers, particularly in helicopter development.
Connection to Charles Lindbergh
The failure of the Sikorsky S-35 indirectly opened the door for Charles Lindbergh to win the Orteig Prize in 1927 aboard the Spirit of St. Louis. Lindbergh’s successful nonstop flight transformed global aviation history.
Legacy of the Sikorsky S-35
Today, the Sikorsky S-35 is remembered as one of the great “what-if” aircraft in aviation history. While only one example was ever built, its story represents the fearless innovation of the Golden Age of Aviation.
The aircraft demonstrated the determination of early aviators to conquer long-distance flight despite limited technology and enormous risks. Though overshadowed by Lindbergh’s later success, the S-35 remains an important milestone in the evolution of transatlantic aviation.
Conclusion
The Sikorsky S-35 was more than just a failed airplane project. It symbolized the ambition, innovation, and danger that defined early aviation history. From its advanced trimotor design to its tragic crash at Roosevelt Field, the aircraft continues to fascinate aviation enthusiasts and historians nearly a century later.
Its story serves as a reminder that aviation progress was built not only on famous successes but also on daring experiments that pushed technology beyond its limits.
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