In 1929, an example, developed from the A 17, was built with a BMW VI engine and fitted out for aerial photography and survey work and designated A 21. The cabin was equipped with a darkroom
| Type |
Special aircraft for aerial pfotography |
| Engine |
1 BMW VI u |
| Dimensions |
Length 13.0 m,height 4.00 m, span 20.0 m, wing area 62,5 m2 |
| Weights |
Empty 2700 kg, flying weight 3800 kg, wing loading 61 kg/m2 |
| Performance |
Max. speed 200 km/h, service ceiling 7000 m, range 700 km, landing speed 85 km/h |
| Type |
Werk.Nr |
Registration |
History |
|
54 |
D-1737 |
In Oct. 1929 to DVL e. V., Adlershof |
|
56 |
D-1738 |
|
Use: Photography and surveying purposes.
Wing deck continuous, cantilevered, placed on top of the hull. Wing thickness and depth decreasing towards the ends. A twist-resistant box spar, plywood ribs, plywood planking.
Hull rectangular, with a straight top. Welded tubular steel truss with fabric covering. The cabin floor is open with a width of 0.8 m and a depth of almost 3 m. The opening can be covered by seven floor parts of any size and temporarily closed by a special blind to protect the photographic devices from any dirt during take-off or landing. Both side walls of the cab have openings closed by blinds for inclined shots in a width of almost 2 m, including the entrance opening designed as a sliding door. Behind the cabin there is a darkroom with a drying and a wet work table, a seat for the photographers, windows with sliding colour filters, bottle and equipment cabinet. Driver's cab under flying deck leading edge, separated from cabin by door.
Engine: water-cooled engine in fuselage tip.
Chassis: Axle bearing hinged by V-struts on the lower edges of the fuselage, supported by vertical spring struts to the support deck.
