light passenger aircraft ChAI-1 **** February 1934
AIRCRAFT INVESTIGATION
weight and performance calculations for the ChAI-1
ChAI-1
role : light passenger aircraft
importance : ****
first flight : operational : February 1934
country : Russia
design : Joseph Grigoryevich Neman
production : 43 aircraft
general information :
Nicely smooth design, with very low drag coefficient
users : Aeroflot
crew : 1 passengers : 6
powerplant : 1 Shvetsov M-22 air-cooled 9 -cylinder radial engine 480 [hp](357.9 KW)
normal rating without supercharger
dimensions :
wingspan : 14.8 [m], length : 10.41 [m], height : 3.8 [m]
wing area : 33.17 [m^2]
weights :
max.take-off weight : 2600 [kg]
empty weight operational : 1630 [kg] useful load : 600 [kg]
performance :
maximum speed :313 [km/hr] at sea-level
cruise speed :297 [km/u] op 100 [m]
service ceiling : 6500 [m]
range : 1130 [km]
description :
low-winged monoplane with retractable landing gear with tail wheel
tapered wing with no flaps airfoil : unknown
engine in the nose, fuel tanks in the wing, landing gear attached to the wing
construction : fuselage > semi-monocoque wooden fuselage covered with plywood, wooden wing covered with plywood
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.69 [ ]
estimated diameter airscrew 3.19 [m]
relative pitch (J) : 1.06 [ ]
power loading prop : 112.21 [KW/m]
theoretical pitch without slip : 3.88 [m]
blade angle prop (fixed) : 27.28 [ ]
reduction : 0.75 [ ]
airscrew revs : 1500 [r.p.m.]
aerodynamic pitch at max. continuous speed 3.39 [m]
blade-tip speed at max.continuous speed : 264 [m/s]
propellor noise in flight : 92 [Db]
calculation : *1* (dimensions)
measured wing chord : 2.56 [m] at 50% wingspan
mean wing chord : 2.24 [m]
calculated average wing chord tapered wing with rounded tips: 2.25 [m]
wing aspect ratio : 6.6 []
seize (span*length*height) : 585 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 8.9 [kg/hr]
fuel consumption(cruise speed) : 69.0 [kg/hr] (94.2 [litre/hr]) at 57 [%] power
distance flown for 1 kg fuel : 4.31 [km/kg] at 3250 [m] height, sfc : 336.2 [kg/kwh]
estimated total fuel capacity : 406 [litre] (298 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 395.0 [kg] = 1.10 [kg/KW]
weight 54.4 litre oil tank : 4.62 [kg]
oil tank filled with 2.7 litre oil : 2.4 [kg]
oil in engine 2.0 litre oil : 1.8 [kg]
fuel in engine 2.4 litre fuel : 1.79 [kg]
weight 40.0 litre gravity patrol tank(s) : 6.0 [kg]
weight Burgess type silencers : 7.2 [kg]
weight starter (E.H.I. - Electric Hand Inertia): 8.8 [kg]
weight airscrew(s) incl. boss & bolts : 40.1 [kg]
total weight propulsion system : 468 [kg](18.0 [%])
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fuselage skeleton semi-monocoque (wood gauge : 6.11 [cm]): 166 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 3.0 rows
weight 1 fire extinguisher : 3 [kg]
weight 8 windows : 7.2 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 1.45 [m] cabin length : 3.23 [m] cabin height : 1.70 [m]
weight cabin furbishing : 14.6 [kg]
weight cabin floor : 24.2 [kg]
bracing : 21.8 [kg]
fuselage covering ( 20.5 [m2] plywood 10.8 [mm]) : 132.5 [kg]
fuselage (sound proof) isolation : 5.2 [kg]
weight radio navigation equipment : 6.0 [kg]
weight Sperry gyro auto-pilot - course control equipment : 1.5 [kg]
weight instruments. : 5.0 [kg]
weight lighting : 1.5 [kg]
weight electricity generator : 2.8 [kg]
weight controls : 5.7 [kg]
weight seats : 35.0 [kg]
weight air conditioning : 5 [kg]
weight engine mounts & firewalls : 18 [kg]
total weight fuselage : 451 [kg](17.3 [%])
***************************************************************
weight 3.0 [mm] plywood wing covering : 63 [kg]
total weight wooden ribs (63 ribs) : 155 [kg]
weight fuel tanks empty for total 366 [litre] fuel : 29 [kg]
total weight 4 wooden spars : 194 [kg]
weight wings : 411 [kg]
weight wing/square meter : 12.40 [kg]
cantilever wing without bracing cables
weight fin & rudder (2.5 [m2]) : 31.9 [kg]
weight stabilizer & elevator (3.7 [m2]): 46.5 [kg]
total weight wing surfaces & bracing : 519 [kg] (20.0 [%])
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wheel pressure : 1300.0 [kg]
weight 2 Dunlop wheels (880 [mm] by 135 [mm]) : 49.2 [kg]
weight tailwheel(s) : 5.9 [kg]
weight Bendix wheel-brakes : 2.2 [kg]
weight Dowty shock absorbers : 3.0 [kg]
weight wheel hydraulic operated retraction system : 10.8 [kg]
weight undercarriage with axle 90.7 [kg]
total weight landing gear : 161.8 [kg] (6.2 [%]
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calculated empty weight : 1599 [kg](61.5 [%])
weight oil for 4.6 hours flying : 40.8 [kg]
calculated operational weight empty : 1640 [kg] (63.1 [%])
published operational weight empty : 1630 [kg] (62.7 [%])
___o___
"
weight crew : 81 [kg]
weight fuel for 2.0 hours flying : 138 [kg]
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operational weight empty: 1859 [kg](71.5 [%])
weight 6 passengers : 462 [kg]
weight luggage & freight : 138 [kg]
operational weight loaded: 2459 [kg](94.6 [%])
fuel reserve : 141.0 [kg] enough for 2.04 [hours] flying
operational weight fully loaded : 2600 [kg] with fuel tank filled for 94 [%]
published maximum take-off weight : 2600 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (Take-off) : 7.26 [kg/kW]
power loading (operational without useful load) : 5.19 [kg/kW]
total power : 357.9 [kW] at 2000 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 5.5 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.2 [g]
design flight time : 3.04 [hours]
design cycles : 7061 sorties, design hours : 21468 [hours]
operational wing loading : 550 [N/m^2]
wing stress (3 g) during operation : 133 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.35 ["]
max. angle of attack (stalling angle) : 12.69 ["]
angle of attack at max. speed : 0.12 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.11 [ ]
lift coefficient at max. speed : 0.12 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
induced drag coefficient at max.speed : 0.0009 [ ]
drag coefficient at max. speed : 0.0199 [ ]
drag coefficient (zero lift) : 0.0190 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 2531 [kg]): 118 [km/u]
landing speed at sea-level (normal landing weight : 2005 [kg]): 121 [km/hr]
max. rate of climb speed : 184 [km/hr] at sea-level
max. endurance speed : 161 [km/u] min.fuel/hr : 47 [kg/hr] at height : 610 [m]
max. range speed : 233 [km/u] at cruise height : 4267 [m]
cruising speed : 297 [km/hr] at 3250 [m] (power:77 [%])
max. continuous speed : 305.18 [km/hr]
maximum speed : 313 [km/hr] at 100 [m] (power:110 [%])
climbing speed at sea-level (loaded) : 302 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 143.3 [km/u]
static prop wash : 77 [km/u]
take-off distance at sea-level gras field : 798 [m]
take-off distance at sea-level over 15 [m] height : 950 [m]
landing run : 184 [m]
lift/drag ratio : 14.28 [ ]
climb to 1000m with max payload : 4.59 [min]
climb to 2000m with max payload : 10.72 [min]
climb to 3000m with max payload : 19.77 [min]
practical ceiling (operational weight empty 1859 [kg] ) : 6500 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:2565 [kg] ) : 4700 [m]
calculation *10* (action radius & endurance)
published range : 1130 [km] with 1 crew and 616.7 [kg] useful load and 88.1 [%] fuel
range : 1202 [km] with 1 crew and 600.0 [kg] useful load and 93.7 [%] fuel
range : 1538 [km] with 6.0 passengers with each 10 [kg] luggage and 119.9 [%] fuel
Available Seat Kilometres (ASK) : 9227 [paskm]
max range theoretically with additional fuel tanks total 1199.3 [litre] fuel : 3662 [km]
useful load with range 500km : 763 [kg]
useful load with range 500km : 6 passengers
production (useful load): 227 [tonkm/hour]
production (passengers): 1784 [paskm/hour]
oil and fuel consumption per tonkm : 0.34 [kg]
fuel cost per paskm : 0.034 [eur]
crew cost per paskm : 0.066 [eur]
I=I°_°°°°/
economic hours : 12775 [hours] is less then design hours
time between engine failure : 845 [hr]
in case of engine failure only option is emergency landing
unreliable engine, high risk of PUF
writing off per paskm : 0.041 [eur]
insurance per paskm : 0.009 [eur]
maintenance cost per paskm : 0.164 [eur]
direct operating cost per paskm : 0.314 [eur]
direct operating cost per tonkm : 3.140 [eur]
Literature :
Piston-engined airliners page 41
DISCLAIMER Above calculations are based on published data, they must be
regarded as indication not as facts.
Calculated performance and weight may not correspond with actual weights
and performances and are assumptions for which no responsibility can be taken.
Calculations are as accurate as possible, they can be fine-tuned when more data
is available, you are welcome to give suggestions and additional information
so we can improve our program. For copyright on drawings/photographs/
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(c) B van der Zalm 22 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4