Antonov AN-2 Specifications:


The following data applies to all An-2s:


Aircraft was designed by Oleg Konstantinovich Antonov at Kiev for utility transport
use requiring short field performance.

Most were manufactured by PZL-Mielec in Poland.



List of PZL bulletins:



 Power Plant:

WSK-PZL-Kalisz (Wytwornia Sprzetu Komunikacyjnego-PZL-Kalisz)
Shvetsov ASz-62 IR Geared 9 Cylinder 1823 Cu. In. Radial Engine, rated at 1000 HP max,
driving a 4 blade AW-2 Propellor.
    _________________________________________

    Take-Off Power         1000 HP at 2200 RPM        110 gph   5 minutes max.

      Rated Power               820 HP at 2100 RPM

      Max. Continuous          738 HP at 2030 RPM

      75% Power                 615 HP at 1910 RPM

      50% Cruise                  410 HP at 1670 RPM        45 gph
    _________________________________________

      Propellor Gear Ratio              0.637 to 1        11:16
 

      1800 RPM and 800 mm Hg manifold pressure for typical climb.
      1600 RPM and 700 mm Hg for typical cruise.
      Use 100 Octane Aviation Grade minimum.


 Airframe Construction:

Wings are of an unequal span single bay biplane design, all metal construction, with fabric covering.
Fuselage is of all-metal stressed skin semi-monocoque construction. Tail is a braced all metal structure with fabric covering. Wing area is 770 square feet total.
Note: wings have full length leading edge slats and ailerons droop with flap actuation to provide great STOL performance.

Controls:
Ailerons, rudder, and elevators are all manually controlled with pushrods and cables. Flaps and trim electrically operated. Automatic leading edge slats provide excellent slow speed safety and high lift.

Landing Gear:
Conventional configuration (tail wheel design) with split axle, long stroke oleo shock absorbers on the main mounts and a fully castoring and self centering tail wheel. Brakes are pneumatically operated.

Crew: Normally two pilots, may be flown single pilot when no passengers are aboard.

Dimensions:
Length= 41 feet, 9 inches;  Wing Span= 59 feet, 8 inches; Height= 13 feet, 2 inches (tail down).
Total Wing Lift Area=256.6 sq. ft.      156.2 upper     100.4 lower
Cargo compartment= 13.5 feet long by 5 feet wide by 5.9 feet tall (398.25 cubic feet).
Cargo door opening: 4.5 feet wide by 5 feet tall.

Weights:
Empty= 7,600 lbs.; Max Take Off= 12,125 lbs.; Max Landing= 11,574 lbs.;
Max fuel= 2,000 lbs. (312 USG);
Oil Qty.=22 Gallons Max.   (13 Gallons minimum to 18 Gallons normal.)
Useful load with max fuel= 2,525 lbs. (3500 lbs with half fuel carried).



Systems:

Compressed Air System: 8 liter (490 Cu.In.) Air Cylinder at 49 bars (711 PSI) maintained
by engine driven AK-50M compressor and AD-50 relief valve. Pressure gauge is on pilot's
left hand console. A pressure reducer supplies 10 bars (145 PSI) for the main brakes.

The Air Pressure is required for the pneumatic main wheel brakes, but can be used to
charge the landing gear shock absorbing oleo-pneumatic struts when dry nitrogen is
not available. A fitting is also available to fill the tires from this system. The 8 liter
air cylinder can also be charged from appropriate ground support equipment.

Electrical System: 24 VDC battery  with engine driven generator to maintain charge.
Voltmeter and Ammeter on Instrument Panel.
The 28 VDC generator requires at least 900-1000 RPM to kick in.
36 Volt 3 phase 400hz AC power, supplied by two convertors, is used to power the Russian Gyroscopic compass, Artificial Horizon and ADF.

CO2 Fire Extinguishing System with automatic fire detector: Nine fire detectors are located throughout the engine compartment. If the Fire Warning Lamp light, the CO2 system can be activated by breaking the safety seal and pushing the button. The CO2 bottle has an electrically activated pyro-technic cartridge to release the CO2 into the collector.  Portable CO2 Fire Extinguishers are normally installed in the cockpit and cabin as well.

Oil Cooling System: The Oil System consists of a 125 liter (33 gal) Max. permitted
22 gal. tank, suction pump and an external Oil Cooler with electrically controlled shutters.
Use Aeroshell 100 Oil.


                                PERFORMANCE:

The following data applies to all An-2s except float versions which have reduced performance and load capacities.
Data is based on a typical weight of 11,600lbs. in mid-mission.


        Red Line Speed: V-NE  162 kts.
        White Line Flaps: V-FE  70 kts.
        Best Glide:    65 kts.

        Maximum Speed: 139kts. or 160mph. (120kts. more typical)
        Economy Cruise Speed: 100kts. or 115mph. (95kts. more typical)
        Minimum Speed: 49kts. or 56mph.
        Take-Off Speed: 43kts. or 50mph. (15 degrees of flap).
        Landing Speed: 46kts. or 53mph. (30 degrees of flap).
        Stall Speed: 35-40kts. but controlled descents are possible at 25kts. or 30mph.

         Typical SL Take-Off distance to clear 50 foot obstacle: 1600 feet.
         Great STOL performance!
         Minimum SL Take-Off Run: 560 feet.
         (We've done 275 feet roll, empty in 15kt. Head Wind)
         Typical SL Landing distance over 50 foot obstacle: 1400 feet.

         Normal Range: 485nm with 45 min. reserve.
         (550nm max with approx. 6 hours endurance).
         Max SL Rate of Climb: 680 fpm, 30 minutes to 14,425 feet.
         Ceiling: 14,425 feet with 1,100lbs. of cargo.
         (we've managed 9,500 feet with 2500lb. load in Guatemala).

          Note: Tolerable Cross wind component is only 8 kts with full flaps. Aircraft cannot be
          taxied with wind in excess of 20 kts.
 
 




Weight and Balance measurement in 3-point attitude


The manual instructs us to measure the weights on each wheel with the aircraft in a level
attitude and, mathematically, this is the simplest way to determine the center of gravity.

In practice, however, this procedure is difficult and hazardous since the tail wheel must be
lifted about 66 inches off the ground to level the aircraft. ( forcing bulkhead #5 to be vertical.)

Using some mathematics and trigonometry, we can avoid having to jack the AN-2 tail
high into the air. We can get the answer by jacking the tail only a foot or two high.

Summing moments about the tail wheel, the Weight on the Mains must counteract the Total Weight
of the aircraft at the CG. (see figure below).  Total Wt. = Weight on Mains plus Weight on Tail wheel.

The tail wheel is at about bulkhead # 24 (9130mm) so distance to bulkhead #5 (1350mm) = 7780mm
or 306.3 inches.

In three point attitude the distance L1 from tail wheel axle to main gear axle line is 325 inches and
the angle Phi is about 11.5 degrees....  L2 = L1 * Cos(11.5 deg)  = 318.5 inches.

Thus L2 extends from tail wheel axle to 12.2 inches forward of bulkhead #5.

The Aircraft manual defines thebeginning of the Mean Aerodynamic Chord as being 2 inches aft
of Bulkhead #5. The total length of the MAC is 2.269 meters or 89.93 inches.

We also need to know the height of CG as it may not be on the center line of the aircraft.
(From the two aircraft we have measured, it turns out that the cg is very near the aircraft center
line....about 80 inches above the main gear axle... aircraft in level flight attitude.)

The weight on the mains will increase as we lift the tail. The amount of increase is affected by the
height of the CG as well as its distance behind the main gear axle.



Procedure using three scales:

Scales will need to accommodate up to 5000 pounds.

This procedure should  be carried out for an EMPTY aircraft.

(1) After calibrating and placing scales under each wheel, measure distance from tail wheel axle
to main gear imaginary common axle. This is L1 and it should be approximately 325 inches.
(varies slightly with strut fill)

(2) Measure angle of bulkhead #5 which separates cockpit from cabin. It should be approximately
11.8 degrees off of vertical. (varies slightly with main strut lengths)

(3) Sum the weights on the Mains to get Wm. Record this number and the weight on tail, Wt.
   Sum all three weights to get W.

(4) Now jack the tail up until the sum of the  weight on the main gear increases by 100 pounds
 this required a height of 19 inches in our example. Record the new weight on the mains and
the height that the tail wheel was raised above the  tail scale.

(5) Enter the data into the AN-2 Center of Gravity Calculator excel sheet and it will calculate
the cg location and the % mean aerodynamic chord.

Click here to Down load the AN-2 CG Calculator Excel sheet
 

Empty CG should be between 17 and 24 %  MAC.....
Fully loaded CG should be between 20 and 30 % MAC    (Do not attempt parachute mode descent
.. full flaps, full elevator....  with CG aft of 30 %!)

Fwd. CG limit = 17 % MAC!           Aft CG absolute limit = 32 % MAC
 



M = 82 in. x Tan(phi)   approx. 16.7 inches..





Removing the Oil from the previous calculations:

Using Bulkhead 5 as reference:
                                       Weight       Arm          Moment
Aircraft with Oil             7587         + 19.45   =  +147567
removing Oil                   -120         -  63.0    =   +    7560
_____________________________________________
                                        7467                           +155127                155127 / 7467 = 20.77 in. arm

Hence N71AN empty baseline is:

Using Bulkhead 5 as reference:
                                       Weight       Arm          Moment
Empty Aircraft               7467         +20.77    = + 155127


Once the Center of Gravity has been determined for the EMPTY aircraft, weight and balance
calculations for the loaded aircraft can be calculated.

Assume this Aircraft has empty weight of 7465 lbs.  and CG is 20 inches aft of bulkhead 5.
This is equivalent to a typical AN-2 utility aircraft ( 20.15 % MAC EMPTY)

Bulkhead #5, the bulkhead separating the cockpit from the main cabin, is used as the point of
reference in these calculations.   Fwd of # 5 will be negative...  Aft of #5 will be positive.



Use 6 lbs/gallon for weight of fuel.......... 1200 liters = 317 gallons  = 1902 lbs. max fuel

Use 7.5 lbs/ gallon for weight of Oil .....  100 liters = 26.42 gallons  = 198 lbs.

TABLE:                                weights        inches from #5         Moment
___________________________________________________________
Typical Empty AN-2              7465 lbs.            +20             + 149,300 in.lbs.
Crew                                        380 lbs.            -13.2             -     5,016
Oil        (16 gal.)                      120 lbs.            - 62.4            -     7,488
Fuel      (200 gal.)                  1200 lbs.           + 37              +   44,598
Cargo                                     1000 lbs.           +100             + 100,000
____________________________________________________________
                                             10,165 lbs.                               + 281,394

        CG = Sum of Moments / Sum of Weights    = 281,394 / 10,165  =  27.68  inches aft of #5

        Note: beginning of chord is 2 inches aft of bulkhead #5... so we subtract 2 inches...

     % MAC = 27.68 - 2 / 89.33   = 25.68 / 89.33 =  0.2875 or 28.75 % MAC

Limits are 17% to 32 %
Recommended range is between 23% and 27%......



Note for Sky Diving Clubs:  Clustering together at the exit door can shift the center of gravity
far enough aft to make the AN-2 unmanageable!

Weight and Balance measurements with aircraft tail jacked up to level............

Excel worksheet for AN-2 in level attitude.

This figure is useful in determining location of aircraft loads.....

       This page still under development...............