Praga E-40

The Praga E-40 was a single engine, two seat, biplane basic trainer, built in Czechoslovakia in the mid-1930s.

Praga E-40
Role Basic trainer
National origin Czechoslovakia
Manufacturer ČKD-Praga
First flight c.1936
Number built 1?

Design and development

The E-40, one of several Praga trainer designs, was a single-bay biplane with open, tandem cockpits. The swept wings had twin wooden spars and a mixture of plywood and fabric covering. Ailerons were fitted to the lower wing and the upper wing had a cut-out on its trailing edge to enhance visibility from the forward cockpit. The N-form interplane struts were steel and the bay braced with streamlined wires. A pair of vertical N-form struts joined the wing centre section to the upper fuselage. The fixed tail surfaces were wood framed and plywood covered; the tailplane was strut braced from below. Elevators and rudder were fabric covered over steel frames. The rudder had a trim tab.[1]

The fuselage of the E-40 was a steel structure, rigidly braced at the front and wire braced aft. The nose and the upper decking were covered with detachable steel panels; fabric covering was used elsewhere. Fuel and engine oil tanks were in the fuselage. The E-40 was powered by a four-cylinder 63/71 kW (85/95 hp) Walter Minor air-cooled, inverted piston engine driving a two-blade propeller. It had a split type main undercarriage with wheels on V-form legs mounted just forward of the wing leading edge. Rubber-in-compression spring units were mounted in extended hubs; the pistons of these units were held in place on a shallow, inverted V strut, itself attached to the lower fuselage via a steel tube pyramid. The tailwheel castored and had rubber springing within the rear fuselage.[1]

Operational history

There are no records of the E-40 entering production and it is possible that only the prototype, OK-EDA,[2][3] was built.

Specifications

Data from Jane's All the World's Aircraft 1938[1]

General characteristics

  • Crew: 2
  • Length: 8.15 m (26 ft 9 in)
  • Wingspan: 9.0 m (29 ft 6 in)
  • Height: 2.85 m (9 ft 4 in)
  • Wing area: 20.6 m2 (222 sq ft)
  • Empty weight: 470 kg (1,036 lb)
  • Gross weight: 720 kg (1,587 lb)
  • Powerplant: 1 × Walter Minor 4-cylinder inverted air-cooled, 63 kW (85 hp)
  • Propellers: 2-bladed

Performance

  • Maximum speed: 165 km/h (103 mph, 89 kn)
  • Cruise speed: 135 km/h (84 mph, 73 kn)
  • Range: 500 km (310 mi, 270 nmi)
  • Service ceiling: 4,000 m (13,000 ft)
  • Time to altitude: 16 min to 2,000 m (6,560 ft)


gollark: Git stands for GIT Is Tremendous.
gollark: The stages of git clone are: Receive a "pack" file of all the objects in the repo database Create an index file for the received pack Check out the head revision (for a non-bare repo, obviously)"Resolving deltas" is the message shown for the second stage, indexing the pack file ("git index-pack").Pack files do not have the actual object IDs in them, only the object content. So to determine what the object IDs are, git has to do a decompress+SHA1 of each object in the pack to produce the object ID, which is then written into the index file.An object in a pack file may be stored as a delta i.e. a sequence of changes to make to some other object. In this case, git needs to retrieve the base object, apply the commands and SHA1 the result. The base object itself might have to be derived by applying a sequence of delta commands. (Even though in the case of a clone, the base object will have been encountered already, there is a limit to how many manufactured objects are cached in memory).In summary, the "resolving deltas" stage involves decompressing and checksumming the entire repo database, which not surprisingly takes quite a long time. Presumably decompressing and calculating SHA1s actually takes more time than applying the delta commands.In the case of a subsequent fetch, the received pack file may contain references (as delta object bases) to other objects that the receiving git is expected to already have. In this case, the receiving git actually rewrites the received pack file to include any such referenced objects, so that any stored pack file is self-sufficient. This might be where the message "resolving deltas" originated.
gollark: UPDATE: this is wrong.
gollark: > Git uses delta encoding to store some of the objects in packfiles. However, you don't want to have to play back every single change ever on a given file in order to get the current version, so Git also has occasional snapshots of the file contents stored as well. "Resolving deltas" is the step that deals with making sure all of that stays consistent.
gollark: A lot?

References
  1. Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. p. 95c. ISBN 0-7153-5734-4.
  2. "GoldenYears". Archived from the original on 2012-02-19. Retrieved 2010-02-27.
  3. "E-40 image". Retrieved 2011-10-13.


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