PZL M-28 Bryza Skytruck. 1984r. English version

Kraków June 8, 2018
270b Section July 22 1984
PZL Mielec M-28
Transport plane, multi-tasking and highly specialized.


Construction of PZL M-28
The aircraft is produced in serial PZL Mielec. It is a communication plane for transporting passengers and cargo under extreme climatic conditions. It has SLOT properties (short takeoff and landing). A twin-engine, turboprop, high-winged, high-winged, metal-engineered turboprop.

Classic double-girder wings. Divided technologically into three parts. The center wing and outer parts that are attached. The outline of the central part is rectangular and the outer part is trapezoidal. The construction of the caisson type panel. The caisson is created by girders, ribs and working cover. The caissons, both internal and in the attachments, are integral fuel tanks. The outside parts have a rich mechanization. On the leading edge there are two-sectional gills. On the upper surface, two-section chopsticks (slots). At the trailing edge of the flaps and ailerons. The left aileron has a balancing flap. Initially, the shuttlecocks were covered with canvas. This is not the end. Two flaps, left and right and interrupters (slots) were attached to the center wing. All two-slot type flaps. The wingspan is 22.073 m and the largest chord is 1.886 m.

The fuselage of a metal structure consists of a load-bearing cover, stringers, beams and frame. Integral parts of the structure are the frames of the viewports and windows of the crew cabin. In terms of technology, the hull is divided into three parts. A center-plane is attached to the middle part of the two frames in the upper zone. A rudimentary patch was attached to the bottom part of the fuselage, and to its ends, shaving the main landing gear and down the main wings. The floor of the loading cabin is adapted to increased pressure.

Access to the aircraft is provided by the door located in the left side. The crew and passengers enter through it.

Behind the fuselage are loading doors and stairs. Double leaf doors are opened to the outside, and in newer solutions to the inside. The dimensions of the hold: length 5.26 m (17.2 ft), width 1.74 m (5.7 ft), height 1.72 m (5.7 ft). Passenger cabin with 18 + 1 seats. The distance between the seats is 0.72 m (2.36 ft), the passage width is 0.354 m (1.16 ft).

In the rear part of the fuselage, a horizontal tail is attached to the two frames.

The pitch is in the case of the letter H, with a relatively large area. This large surface provides excellent controllability at low and high speeds. Horizontal construction is one-piece, double-girder, fixed with four fittings to the frame of the hull. They are equipped with a two-part rudder with balancing flaps. Vertical height doubled with a division into a rudder and ballasts. Structurally single-girder. Each rudder has a balancing flap. Initially, all the rudders were covered with canvas. As a result of many years of exploitation, it was decided to vertical deviate from the plane of the axis of symmetry by about 2 degrees, in order to compensate for the effect of air flow disturbed by working propellers.

The landing gear of the aircraft allows it to be used at small airports and landing sites with grassy, ​​marshy, snowy, gravel or sandy surfaces. The aircraft is equipped with a fixed chassis with a front wheel. All single wheels. Low pressure tires. The shins of the front chassis are attached to two floor beams. The front wheel is hydraulically controlled to the left-right 50 degrees, unbraked. After detachment from the ground, the front wheel automatically sets itself in a neutral position, offering minimal resistance. The tire size is 595 x 320 mm. The shafts of the main landing gear are attached to the residual patches that ensure sufficient spacing. The main landing gear spacing is 3.405 m, and the chassis base is 4.40 m. Tire size 720 x 320 mm. Braking system of the main hydraulic chassis wheels with anti-slip system (ABS). It is possible to brake each wheel separately. The chassis can be supplemented with skis, which allows it to be used on a thick layer of snow.

PZL-10 S / TWD-10 B engine
The propulsion system provides the aircraft carrying 15-20 passengers at a speed of 300 - 350 km / h, for a distance of 375 - 690 km. The maximum range is 1 300 km. In the event of failure of one of the engines, the aircraft may continue to start and climb at 3.2 m / s.

The drive consists of two PZL-10 S turboprop engines, which are licensed counterparts of TWD-10 B Soviet engines. Manufacturer PZL-Rzeszów. The engine compressor has 6-degree axial and 1-degree radial stress. An annular combustion chamber to which fuel supplies rotating injectors. 2-stage turbine. Power from the drive turbine is transmitted by a high-speed reducer, intermediate shaft, planetary gear reducer.

A single-stage axial turbine drives the propeller through a high-speed gear reducer, an intermediate shaft and a propeller planetary reducer forward. The aircraft aggregate drive box is moved by a high speed gear reducer. The propeller reducer is additionally driven by the propeller speed controller and the speed controller of the power turbine.

Three-blade propellers, rearranged AW-24 AN. The adjustment of propellers takes place to a large extent. By setting in the flag to the negative string.

The power unit is also included; airplane aggregate drive box, oiling and venting system, power supply system and automatic engine adjustment and propeller pitch regulation, anti-icing system, electrical system.

The engine units are driven from a drive box, cinematically coupled to the turbocharger.
The engine is equipped with an anti-pumping system, which consists of an air release valve after the 6th stage of the compressor and two bleedings on the combustion chamber hull.

Fuel supply only in wings of 1 960 liters, which is 516 US gal. The capacity of the tanks in the centrifuge is 620 liters (163 US gal), and in the extreme parts 1 340 liters (353 US gal). A cross-type fuel system that powers each engine independently. The system allows all fuel to be delivered to one engine. In the event of failure of fuel pumps, you can continue to supply engines with fuel, but only from tanks located in the outer parts of the wings. The tanks can be filled individually, through upper infusions or pressurized through the central infusion. A tank overflow protection system was used, with the option of manually controlling the filling level of tanks.

The engine lubrication system consists have two circuits; the turbocharger circuit and the drive turbine circuit. Each of the circuits has its own assembly including a discharge pump and a suction pump assembly.

The engine's advantage is; low unit fuel consumption, current control of the engine condition, continuous vibration measurement and signaling their permissible overrun, automatic protection against exceeding the permissible gas temperatures behind the turbine turbine, automatic protection against exceeding the maximum turbine revolutions, easy access to individual components.

Together with the engine license, Poland obtained new technologies; precise casting of the working vanes and guide vanes. Rolling of working vanes. Surface hardening of working blade blades by vibration method. Automatic welding in an argon shield. Electron beam welding.

The basic data of the engine and propeller are;
- engine type - turboprop with a free turbine and extended propeller reducer.
- Starting power on the propeller shaft 705 kW (960 hp).
- Nominal power on the propeller shaft 574 kW (780 hp).
- Ambient temperature from minus 50 degrees C to plus 40 degrees C.
- Pulling propeller with automatic and involuntary changeable pitch, set in a flag and reverse.
- 2.8 m in diameter.

At the end of the 90-ties, 5-blade propellers from Hartzell were started for PZL-10 S engines. Such a drive was used in many Polish military M-28 Bryza.

PT6A-65B engine. 1993.

Poland wanted to sell M-28 aircraft to capitalist countries. To make this possible, other engines had to be used. The choice fell on Pratt-Whitney from Canada. With Pratt-Whitney, Poland has been cooperating for many years. The engine designated PT6A-65B was selected. The engines have a capacity of 2 x 809 kW (2 x 1 100 HP) and a nominal 2 x 736 kW. For the engines there are dedicated 5-blade HC-B5MP propellers from Hartzell. The first flight with these M-28 engines was made in 1993.

Pratt & Whitney Canada PT6 engines are one of the most popular turboprop engines in the world. PT6 motors have gained recognition thanks to reliability. The repair intervals are 3 600 or 9,000 hours, and the parts of the hot engine are 1 800 - 2,000 hours. The engines have power from 500 hp to 1,600 hp. These engines are also built for helicopters.

Pratt & Whitney Canada began working on turboprop engines in 1956. The need was foreseen to replace piston engines with engines with a much better power to weight ratio. A small budget of $ 100,000 was given to the program. The program was developing very slowly. In 1958, a 450 hp engine project was created. In February 1960, the first prototype was launched. Flight tests began in May 1961. The serial production began in 1963. By 2010, over 40,000 PT6 engines were built.

The PT6 engine uses the main spool technology with an additional so-called free turbine. The air flow through the engine is from the rear of the engine to the front. The engine is built from two main sections, thanks to which the engine can be easily separated and renovated. The air to the engine falls after the 180 degree turn in relation to the direction of flight. Here is a compressor with 3 stages (or depending on the version with 4 stages) axial and one-degree radial. Compressed air goes to the annular combustion chamber where another 180 degree turn occurs. Some of the air falls into the flame insert and the rest is used to cool the cartridge. Once again, the return is 180 degrees. The exhaust gases are closer to the main shaft. Now the gases are sent to a single-stage turbine that drives the compressor. The main spool has a rotational speed of 45,000 rpm. Now, the exhaust gas goes to a free turbine, which is 30,000 rpm and drives the propeller through the shaft and reducer. The free turbine is one-stage or in stronger versions 2-stage. The propeller rotates at speeds from 1,900 rpm to 2,200 rpm. The flue gas escapes through the two side collectors once again changing direction by 180 degrees. The main transmission is of the planetary type in the reducer. Some aircraft powered by PT6 engines have engines facing backwards, which means that the propeller is of the pusher type.

Comparing the PT6 engine with the PZL-10 S engine is more advantageous for the first. The PT6 engine has a much more compact design, which means it has less mass. Despite the smaller compressor, it achieves higher rotational speeds. There is a higher temperature in the combustion chamber. It hasn't long shaft that needs to transfer torque to the rear of the engine.

A version PT6A-65B was installed on the PZL M-28. It was 1993 and two new PZL M-28 planes with SP-DDF and SP-DFB registrations. 5-blade propellers from Hartzell were also installed. Each engine has a power of 1 100 hp.

Control system.
The aircraft is adapted to be controlled by two pilots. The control system was initially mechanical. The control system in the 80's has undergone some evolution. Finally, the control system ensures, when deflecting the flaps, automatic deflection of the ailerons, by an angle proportional to the angle of release of the flaps. The indicator located in the cockpit's cabin informs about the position of the flaps. Rudder, rudder, left aileron have electrically controlled balancing flaps. Interrupt control is hydraulic. Control of the flaps by means of a hydraulic jack through a mechanical system. The aircraft received a system that reduces the asymmetry of the thrust in the event of a defect in one of the engines. Then automatic interrupters are swiveled on the side of the running engine.

Hydraulic installation
The hydraulic system moves the front wheel, brakes the wheels of the main chassis, opens and closes the valves, opens the interrupters. The working pressure in the installation is 14.7 MPa.

Electrical installation.
Three-phase alternating current with a 200/115 V cut provides two generators. Three-phase alternating voltage 36 V provides two emergency generators. The emergency and start-up power supply consists of two cadmium-nickel batteries with a capacity of 25 Ah and a voltage of 27 V.

Anti-icing installation.
The anti-icing installation is very extensive. It starts automatically via sensors or manually. The hot air from the engine compressor is used for de-icing slots, the leading edge of the center wing, the tail, the air grip of the oil cooler and the air conditioning grip. Engine anti-icing systems heats engine air intakes and engine starters. The air inlets that are the walls of the oil tanks are heated by the hot oil of the oil system. Electrically de-iced; shovels and hubcaps of propellers and crew cabin windows.

Avionics of the early versions of An-28 / M-28
The aircraft is capable of flying in difficult weather conditions during the day and at night. It can take off and land without ground visibility. It is provided by groups of devices;
Mechanical - two speedometers, two altimeters, two complex instruments composed of a variometer, a turn indicator, a clinometer.
Navigation - two artificial horizons, the third reserve, two pilot navigational instruments cooperating with the magnetic heading system.
Radio navigation - two radiocompasses, a radio altimeter, a signaling device above the beacon.
The on-board telephone is used to maintain communication between crew members, inform passengers, and listen to radio sets in the crew's earphones.
VHF radio is used for communication with the ground and other airplanes. At a flight altitude of 1,000 m it has a range of 100 km.
Emergency VHF radio is used for communication of the crew with rescue groups after emergency leaving the aircraft. It has a range of 100 km.
VOR / ILS apparatus with a range of 100 km.
Radiometer of small height. It determines the actual height from the ground.
Security and data registration system. Works without crew intervention. Records the technical condition of all basic aircraft devices. Records crew's business data, activities, current date and time. It automatically sends response signals to the call of the radiolocation station, stating, among other things, the aircraft number. Thanks to this, the plane is easy to locate and identify. He constantly controls the altitude of the flight, automatically giving the signal too low. It triggers an alarm signal about a possible threat on board.

Crew cockpit equipment.
Two speedometers, two altimeters, two combined devices (variometer, turn indicator, clinometer). Navigation instruments; two artificial horizons, one artificial horizon, two pilot-navigational instruments cooperating with the magnetic-level system, two radio compasses, a radio altimeter. The signaler over the beacon.

The advantages of the aircraft.
The plane has excellent pilot properties. It to start need a grassy (ground) runway with a length of only 525 m. The takeoff speed is only 135 km / h, and landings 125 km / h. Cruising altitude is 3,000 m. Typical climb velocity is 8 m / s, and descent is 4 m / s, but in emergency situations control at 25 m / s can fall.

Basic differences between PZL An-28 and PZL M-28 B Bryza.
The aircraft has been given the option of suspending the undercarriage trunk with streamlined shapes, capable of lifting up to 300 kg.

The rear ramp was rebuilt several times. Two versions were created. The first modeled on the ramp system on the An-26 aircraft. It opens by dropping down and during the flight it can also move under the hull. Such doors have received versions typically for paratroopers. The second one is a two-part door (double leaf). They are divided like in An-28, along. They hydraulically open to the inside of the aircraft, which also allows parachute landing. Or, manually open them outside. It is basically emergency opening, from the outside. In addition to the door there are also separate stairs. This type of door has transport versions.

Avionics PZL M-28 Skytruck
Radio navigation equipment Honeywell / Bendix King
- area navigation system
- GPS satellite receiver
- DME radiodalay
- weather radar
- radiokompas
- AHRS platform
- exchange system No. 2
- IFF transponder
- radio altimeter
- marker receiver
- two radio stations
- two intercoms
- automatic remote control
- flight parameter recorder (black box)
- voice recorder (black box)

Avionic M-28 B Bryza / M-28 B1R Bryza-1R.
- Honeywell KLN-90B / 900 GPS receiver with the Griebień course system.
- KFC-325 autopilot.
- KNS-81 area navigation receiver.
- Chelton's exploration system.
- radio compass ARK-15 or ADF-806.
- IFF SC10D2 transponder of the Supraśl system.
- RS6113 or AN / ARC-210 radio stations.
- RDR-2000 weather radar.
- Some aircraft have VOR / ILS and TACAN KTU-709 receivers installed.

Avionics M-28 B1E.
- KT-76A transponder.
- Honeywell KX-155 navigational radio station with the Griebień course system.
- RS-6113 radio.

Avionic M-28 B1R Bryza-1R bis.
- Bendix King RNAV Gold Crown avionics.
- KLN-900 GPS receiver.
- KFC-325 autopilot.
- RDS-82VP / RDR-2000 weather radar.
- VOR / ILS KNR-634A system.
- INS LTN-101 system.
- KDF-806 radio compass.
- KNS-660 flight system.
- DM-441B radio modem.
- EFIS-50 indication system.
- LNS-92 laser gyro-compass.

Specialist equipment M-28 B1R Bryza-1R.
- MSC-400 radiolocation observation system (ARS-400 radiolocation station, with IFF receiver).
- CSS-400 command system, or ŁS-10M - the airborne element of the Łeba-2 command system.
- life rafts.
- illuminating bomb ejectors (SAB-100-75, SAB-100-55, SAB-100MW).

Specialist equipment M-28 E Bryza-1E.
- Ericsson MSS-5000 system (IR / UV scanner, SLAR system - two side radars, photo system (DCS620 camera), video (DCR-VX1000 camera).

Specialist equipment M-28 B1R Bryza-1R bis.
- SRM-800 system (ARS-800 radar, MAG-10 magnetometer, HYD-10 buoys, IFF APX-113 system, ŁS-10M console, ESM-10 radio identification system).
- life rafts.
- illuminating bomb ejectors (SAB-100-75, SAB-100-55, SAB-100MW).
- FLIR AN / AAQ-22 Star Safire II.

Special equipment of SAR varieties
- multi-function SAR patrol radar
- FLIR thermal imaging camera
- a radio direction recorder system
- data transmission system (DATA LINK)
- hydro acoustic system with sono-buoy ejector
- magneto metric system
- ESM passive defense system

Avionics of the latest versions of M-28 Bryza
The latest versions of PZL M-28 B / PT have a very modern avionics. The aircraft is equipped with pilot and radio-navigation equipment. They allow flights according to VFR and IFR regulations, day and night. The navigation equipment includes: two multifunctional navigation receivers (VOR / ILS / MLS / GPS), a DME receiver, a TACAN receiver, two ADF receivers, one radio altimeter, an AHRS platform and two EGI platforms. The communication system consists of two V / UHF radios, one HF radio station and one 503-14 emergency radio station. The safety and surveillance system consists of: weather radar, GPWS, TCAS together with two transponders IFF and XPDR.

Pilot and navigation displays are displayed on four MFD displays. External displays play the role of basic PFD pilot devices, while internal MFD displays placed on the central instrument panel work as a system of indication of engine operation parameters and EICAS crew warning and an interactive multi-functional IMDF indicator. Instrument illumination and instruments in the pilot's cabin are adapted for flights in night vision goggles. In order to secure basic ground handling at airports beyond the fixed homing site, basic ground equipment should be mounted on the aircraft, i.e. tug, ladder, tool bag and two wheel stands. For flights over water spaces there is also space for emergency and rescue equipment (rafts, life jackets).

Specification An-28. (Data T-T) 1984
Span 22.073 m (72,41 ft)
Length 13.10 m (43 ft)
Height 4.90 m (16 ft)
Own weight 3 750 kg
Weight max 6 500 kg
Load weight 1 750 kg
Fuel 1,567 kg
Speed max 350 km / h
Cruising speed 335 km / h
Safe minimum speed 165 km / h (89 KTS)
Landing speed 125 km / h
Stall speed 123 km / h (66 KTS)
Lifting speed 8 m / s
Range up to 1 365 km
Range with a maximum load of 560 km
Ceiling 6,000 m
Runway 340 m
Run 490 m
PZL-10 S engines with a capacity of 2 x 705 kW

Specification M-28 B. (Data T-T) 1992
Span 22.06 m (72.4 ft)
Length 13.10 m (43 ft)
Height 4.90 m (16 ft)
Own weight 4 350 kg
Weight max 7,000 kg
Load weight 1 750 kg
Fuel 1,567 kg
Speed max 365 km / h
Cruising speed 335 km / h
Safe minimum speed 165 km / h (89 KTS)
Landing speed 135 km / h
Stall speed 123 km / h (66 KTS)
Lifting speed 8 m / s
Coverage up to 1 230 km
Range with a maximum load of 560 km
Ceiling 6,000 m
Runway 340 m
Run 490 m
PZL-10 S engines with a capacity of 2 x 705 kW

Specification M-28 B / PT (Data T-T) 1993
Span 22.06 m (72.4 ft)
Length 13.10 m (43 ft)
Height 4.90 m (16 ft)
Own weight 4,090 kg
Own weight rescue version (SAR) 5 415 kg
Weight max 7,500 kg
Load weight 2,300 kg + 300 kg in the boot
Fuel 1,766 kg (2,280 liters)
Speed max 365 km / h
Speed max VMO 355 km / h (192 KTS)
Transfer 330 km / h
Safe minimum speed 160 km / h
Speed patrol for rescue version (SAR) 165 km / h
Landing speed 135 km / h
Stall speed 120 km / h
Lifting speed 9 - 11 m / s
The climb speed is 2 360 ft / minute
Range of max. 1,420 - 1,500 km at a cruising altitude of 3,000 m with a margin of 45 minutes of flight
Range with a maximum load of 1,000 km
Time flights 4 hours 50 minutes
Ceiling 6 200 m (with oxygen masks)
Runaway 325 m (1,065 ft)
Runway rescue version (SAR) 440 m
It is 560 m long
Emergency version (SAR) of 330 m
Engines PT 6 A-65 B with a capacity of 2 x 809 kW (2 x 1 100 hp)


Written by Karol Placha Hetman