Focke-Wulf GL 18

Focke-Wulf GL 18
Focke-Wulf GL 18 "Helgoland" ( D-967 , W.Nr. 28) from Luft Hansa
Type:	Experimental and commercial aircraft
Design country:	German Empire
Manufacturer:	Focke-Wulf
First flight:	August 9, 1926
Number of pieces:	3

The Focke-Wulf GL 18 is a German airliner from the 1920s.

history

The GL 18 was the second model developed by Focke-Wulf after the company was founded in 1924. The contract to build a twin-engine aircraft was placed by Junkers in 1925 , who in turn received it from the Turkish government, but for various reasons could not perform. The pattern was intended to be used for experimentation in order to research the flow behavior of the tail unit in multi-engine aircraft in various flight conditions. The motors of GL 18 should therefore be kept adjustable to the longitudinal axis in order to make the flow angle changeable.

Henrich Focke took over the fuselage of the A 16 for the construction and equipped it with an enlarged tail unit with horn compensation and a wing with a larger span. Two air-cooled L-1-a motors from Junkers were used as propulsion , which were placed under the wings. When the GL 18 flew in, which took place in 1925, several problems arose. When the engine power was reduced, there was a stall in the rear of the engine and the resulting top-heaviness with the associated sudden loss of altitude. The cause of the problem was identified and eliminated from the shape of the engine cowling. However, the examinations had taken a long time, so that although the test results were handed over to Junkers on November 25, 1925, together with a price proposal of RM 36,000, the official acceptance did not take place until August 10 and 11, 1926 at the DVL in Adlershof took place. The flights were also restricted by difficulties with the engines developed in 1925. Regardless of this, the model was successfully demonstrated and was adopted by Junkers as the GL 18 a .

Focke-Wulf then built another aircraft called the GL 18 a . An A 16 a with a lengthened and widened fuselage served as the starting model, so that the number of passengers increased from three to four. Two Sh-11 motors from Siemens served as the drive. The last to appear in 1926 was the enlarged GL 18 c with a closed cockpit, twin controls and more powerful Sh 12 engines . It was used by DVS with the registration number D – 1097 . As a further development, the GL 22 appeared in 1927 .

Technical specifications

The GL 18 data were flown by Focke-Wulf in 1925 and handed over to Junkers together with the cost estimate on November 5, 1925. The data flown with the aircraft subsequently designated by Junkers as the GL 18 a can be found in the second column.

Sketch of the GL 18 from 1927

Parameter	GL 18	GL 18 a (Junkers)	GL 18 a (Focke-Wulf)	GL 18 c
crew	1
Passengers	3		4th
length	8.50 m		9.10 m
span	16.00 m
height	2.30 m		2.60 m
Wing area	32.00 m²		34.50 m	32.00 m²
Wing extension	8.00		7.40	8.00
Preparation mass	890 kg	915 kg	1100 kg
Payload	296 kg	220 kg	290 kg
Payload	460 kg	496 kg	550 kg
Takeoff mass	1350 kg	1411 kg	1650 kg
Wing loading	42.18 kg / m²	44.09 kg / m²	47.43 kg / m²	51.56 kg / m²
Engines	two Junkers L 1 a		two Siemens & Halske Sh 11	two Siemens & Halske Sh 12
power	55 kW (75 PS) each		60 kW (82 PS) each	79 kW (107 PS) each
Top speed close to the ground	150 km / h	160 km / h	140 km / h
Cruising speed close to the ground	135 km / h	145 km / h	127 km / h
Rate of climb	1.50 m / s	1.40 m / s	1.85 m / s	2.20 m / s
Service ceiling	3000 m		4000 m	5000 m
Range	400 km	580 km	380 km
maximum flight time	3 h	4 h	3 h
Take-off / landing runway	160 m / 100 m	170 m / 150 m	160 m / 100 m

literature

• Wolfgang Wagner: Der Deutschen Luftverkehr - The Pioneering Years 1919–1925 (=  Die deutsche Luftfahrt . Volume 11 ). Bernard & Graefe, Koblenz 1987, ISBN 3-7637-5274-9 , pp. 185-189 .

Web links

Commons : Focke-Wulf GL 18  - Collection of images, videos and audio files

• Photos and dates. Retrieved January 8, 2016 . 

Remarks

1. ↑ The official first flight date, which refers to the start of the acceptance flights at the DVL in Adlershof. Unofficially, however, the GL 18 was flown in at Focke-Wulf in Bremen the year before.