NachtJagerX

[Data Sheet] Laz-7

laz7-4.jpg

 

 

Model: Lazarov Laz-7 trainer/light night bomber
 
Technical Description:  Single-engine, two-seat monoplane of mixed construction.

 

Short History: Development began after Yugoslavia announced a competition for a new trainer aircraft with a maximum engine power of 160 hp. Documentation was sent to Yugoslavia in 1946. The Laz-7 was placed second in the contest, and funding plus an order for a prototype were sent to Bulgaria. In September 1948, the Laz-7.1 prototype was sent to Yugoslavia for testing, where during one of the test flights, after an overload of 4.9 Gs (and a suspected sabotage of the plane), one of the wings broke off, leading to a crash. The test pilot died. Structural and cockpit visibility problems were fixed on the Laz-7.2 prototype, however it never got sent to Yugoslavia, as the relations between it and the Bulgarian People's Republic worsened. However, the Bulgarian Air Force saw the plane as a suitable trainer and light night bomber, and production of the Laz-7, based on the Laz-7.3 prototype was approved. The plane was liked by the pilots, and it served with the Air Force until the end of the 1950s, and with various aero clubs until the end of its technical resource.
 

Configuration: bomber

 

Production Status

First flight: 1948
Introduction year: 1949

Status: serially produced

Number built: 160


Crew Data
Number of crew: 2
Roles of crew: pilot and instructor-observer
 
Engine Data
Manufacturer: Walter Aircraft Engines
Name: Minor 6-III
Number of engines: 1
Number of cylinders: 6

Configuration: inline

Cooling: air-cooled
Supercharger / Turbo:
Fuel: 80-octane
Dry weight: 128.5 kg
Gear ratio: 
 
Fuel Data
Fuel tanks: 
Fuel consumption:

  • at 160 hp: 53 l/h
  • at 125 hp: 38 l/h

 
Power Data
WEP
Take Off Power: 
Maximum Power: 160 hp, 2500 RPM
Cruising Power: 125 hp, 2300 RPM
 
Propellor Data
Manufacturer: ДСФ Ловеч
Type: fixed-step
Number of blades: 2
Blade diameter: 2.10 m

Material: wood
 
Basic Geometric Data
Length: 8.20 m
Wing span: 10.60 m
Wing area: 16.40 m2

Wing profile: 

  • at fuselage: NACA 23015
  • mid section: 23012
  • at tips: 23009

Height: 2.32 m
Flap area: 1.33 m2

Flap deflection angles: 00 to -480
Elevator area:

Horizontal stabilizer span: 3.00 m

Horizontal stabilizer area: 2.25 m2
Rudder area

Fin area: 1.70 m2
Aileron area1.33 m2
 
Weight Data
Empty weight: 765 kg
Loaded weight:

  • variant A (2 pilots, no bombs): 1120 kg
  • variant B (1 pilot, 6x12 kg bombs): 1130 kg

 
General Performance Data
Maximum speed: 

  • at 0 m: A: 222 km/h ; B: 204 km/h
  • at 500 m: A: 216 km/h ; B: 199 km/h
  • at 1000 m: A: 210 km/h ; B: 195 km/h
  • at 2000 m: A: 194 km/h ; B: 181 km/h

Cruising speed:

  • at 0 m: A: 196 km/h ; B: 190 km/h
  • at 500 m: A: 193 km/h ; B: 188 km/h
  • at 1000 m: A: 190 km/h ; B: 194 km/h
  • at 2000 m: A: 181 km/h ; B: 173 km/h

Minimum speed:

  • at 0 m: A: 97 km/h ; B: 105 km/h
  • at 500 m: A: 98 km/h ; B: 105 km/h
  • at 1000 m: A: 99 km/h ; B: 106 km/h
  • at 2000 m: A: 104 km/h ; B: 110 km/h

Landing speed: 94 km/h

Service ceiling: 

  • variant A: 3700 m
  • variant B: 3500 m

Range: 604-805 km

Flight endurance: 

  • at 500 m: A: 4 h 20 min ; B: 3 h 35 min
  • at 1000 m: A: 4 h 1 min ; B: 3 h 48 min
  • at 2000 m: A: 3 h 51 min

Rate of Climb:

  • at 0 m: A: 2,27 m/s ; B: 1,68 m/s
  • at 500 m: A: 2,04 m/s ; B: 1,52 m/s
  • at 1000 m: A: 1,80 m/s ; B: 1,34 m/s
  • at 2000 m: A: 1,32 m/s ; B: 1,01 m/s
  • at 3500 m: A: 0,60 m/s ; B: 0,50 m/s

 

Armament

  • 2x7.92 mm MG 17, 250 RPG, wing mounted
  • optional/proposed MG 15 for the observer
  • 6x10/20 kg bombs
  • 2x50 kg bombs

Ammunition:

 

Misc:

  • Revi C12D gunsight
  • "Zavod 14" bombsight (refer to the pictures section)


Notes

 

21.12.2014: updated with additional info

29.01.2015: added photos of cockpit and schematics

23.05.2015: updated flight performance data


Sources


1. Aircraft Manufacture in Bulgaria, Dimitar Nedialkov, 2009, p.158-165

2. Лаз-7 Лястовицата, Иван Бориславов, Даньо Йотов, Ретросалон, кн. 7/1999, издава "Еър груп 2000"

3. TYPE CERTIFICATE DATA SHEET No. 2417/59 

 

Additional images

 

0ihGVU7.jpg

 

laz-17.jpg

 

Pilot's cockpit

 

dVYEJiM.jpg

 

Observer cockpit

 

9emiUIW.png

 

 

Schematics

 

KC7HZaa.jpg

 

"Zavod 14" bomb sight

Edited by NachtJagerX
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Good work, any chance that you can find out at what RPM those power values are?

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Trainers will have a hard time getting onto the game.

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It's not a pure trainer, the armed version (the one shown here) was also a light night bomber.

still the armament and bombload is very bad.

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