IVL K.1 Kurki

IVL K.1 Kurki
The Kurki in Suomenlinna in March 1927.
Role	Trainer / Utility aircraft
National origin	Finland
Manufacturer	Ilmailuvoimien lentokonetehdas (IVL)
Designer	Asser Järvinen
First flight	20 March 1927
Introduction	1927
Status	Retired
Primary users	Finnish Air Force
Number built	1

IVL K.1 Kurki (Crane) is a Finnish four-seat trainer and utility aircraft developed by the Ilmailuvoimien lentokonetehdas (Aircraft Factory of the Air Force, IVL) in 1926-1927. Only one example was built, and briefly tested by the Finnish Air Force. The aircraft was also known as Järvisen laatikko (Järvinen's Box) after the designer, Asser Järvinen.

History

The Kurki's development began in 1926 after civilian aircraft had been requested from the IVL, and the factory needed more work. Asser Järvinen and Kurt Berger proposed building a civilian trainer, utility and sport aircraft in August 1926. The Finnish Air Force considered the Kurki to be also suitable for military liaison and training duties, and gave funds for building a prototype in January 1927. By that time the prototype was actually almost finished, as Järvinen and Berger had ordered the construction to start without the Air Force's permission.

The Kurki made its first "flight" on 20 March 1927, but at first only short hops of 100 to 1,000 m were made, as the there were engine problems and the aircraft was severely overweight and nose-heavy, although loading ice into the rear fuselage helped somewhat. Modifications made to the tail allowed the Kurki to really fly, but it was still unstable and prone to so-called dutch rolls. The original ski landing gear was switched for wheels in April.

The wheels were replaced with floats in May 1927, but with abysmal results. Now the Kurki could barely take off, even with light load. The test flights ended on 12 September 1927, after a total of just 13 hours and 19 minutes of flying time. The aircraft had never received a FAF registration code. The test pilot Georg Jäderholm suspected the underpowered 120 hp Siemens-Halske engine, short fuselage and high wing mounting to have crippled the aircraft. Extensive modifications proposed by Järvinen were never carried out.

The Kurki was restored in 2019 and is now on display at the Päijänne Tavastia Aviation Museum in Asikkala.

Specifications

• Crew: 1-4
• Length: 7,53 m (24 ft 8​¹⁄₂ in)
• Wingspan: 12,3 m (40 ft 4 in)
• Height: 2,5 m (8 ft 2 in)
• Wing area: 24 m² (258 ft²)
• Empty weight: 800 kg (1,764 lbs)
• Gross weight: 1,200 kg (2,646 lbs)
• Powerplant: 1 × Siemens-Halske Sh 12 nine-cylinder radial engine; 120 hp (89 kW)

• Maximum speed: app. 142 km/h (88 mph)
• Stall speed: 94 km/h (58 mph)
• Service ceiling: 2,950 m (9,680 ft, never tested)