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weight and performance calculations for the Boeing 307 Stratoliner

Boeing 307 Stratoliner

role : commuter airliner

importance : **

first flight : 31 December 1938 flown by Edmund T.Allen operational : July 1940

country : United States of America

design :

production : 10 aircraft

general information :

Airliner design based on the B-17 bomber but with a wider fuselage.

The prototype crashed during a demonstration to Dutch KLM representatives on 18

March 1939. When performing side-slip test it got in a spin and recovery was not in

time. All 10 people on-board died in the crash, including KLM vice president

P.Guilonard and RLD representative A.G. von Baumhauer .

Tycoon Howard Hughes ordered and received also a 307, registered as NX-19904 to

make a record flight around the world, but the outbreak of WWII prevented this trip

and the 307 was turned into a luxurious VIP plane, named “ The Flying Penthouse ”.

Cargo space below cabin floor for 1816 kg

Fuel capacity : 4826 litre optionally increase to 6435 litre.

First airliner in service with pressurized cabin making it possible to fly at higher

altitude above most of the weather and with more comfort and better economic

performance. Cruising altitude 5790m.

In WWII it was used by the military as C-75 with additional fuel capacity and higher

MTOW for trans-Atlantic flights.

Non-stop flights were made over the North Atlantic between Gander and Prestwick

(3415 km non stop) and the South Atlantic between Natal, Brazil and Accra, Ghana

(4100 km non-stop). It operated remarkably safe and reliable, flying 2.5 years for the

military, total 45000 hours 7.5 million miles (12 mln km, average 266 km/hr) without

trouble or casualty. 267 km/hr was the max.range speed without cabin

pressurization, which was removed from the military aircraft.

They survived the war and as proof of its good design it was taken into civil service

again by TWA who used it until April 1951. They were refurbished by Boeing with

more powerful engines and B-17G wing and now indicated as 307B. Later they were

sold to the French airline Aigle Azur.

users : PanAm, TWA, USAAF, Aigle Azur.

registrations : NX-19901, NX-19904, Panam : NC-19902 “Clipper Rainbow”, NC-19903

“Clipper Flying Cloud”, NC-19910 “Clipper Comet”, TWA : NC-19905 “Comanche”,

NC-19906 “Cherokee”, NC-19907 “Zuni”, NC-19908 “Apache”, NC-19909 “Navajo”.

Aigle Azur : F-BELY, F-BELU, F-BELV, F-BELX, F-BELZ.

crew : 5 passengers : 33

powerplant : 4 Wright GR-1820-G102A Cyclone air-cooled 9 -cylinder radial engine 900 [hp](671.1 KW)

normal rating, supercharged engine, low blower, constant power to height : 2045 [m]

and with 1100 [hp](820.3 KW) available for take-off

dimensions :

wingspan : 32.63 [m], length : 22.6 [m], height : 6.33 [m]

wing area : 138.0 [m^2]

weights :

max.take-off weight : 20420 [kg]

empty weight operational : 13608 [kg] useful load : 4760 [kg]

performance :

maximum speed :387 [km/u] op 1829 [m]

cruise speed :368 [km/u] op 1829 [m]

service ceiling : 7110 [m]

range : 1829 [km]

description :

low-winged monoplane with retractable landing gear with tail wheel

tapered multi-cellular wing with flush-riveted stressed skin

with split flaps airfoil : unknown

engines and landing gear attached to the wings, fuel tanks in the wings

construction : all-metal stressed-skin (Alclad-aluminium) airplane

airscrew :

four Hamilton-Standard constant speed full-feathering 3 -bladed tractor airscrews with

max. efficiency :0.75 [ ]

estimated diameter airscrew 3.43 [m]

relative pitch (J) : 1.16 [ ]

power loading prop : 130.44 [KW/m]

theoretical pitch without slip : 4.52 [m]

blade angle prop at max.speed : 30.20 [ ]

tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency

reduction : 0.69 [ ]

airscrew revs : 1581 [r.p.m.]

aerodynamic pitch at max. continuous speed 3.98 [m]

blade-tip speed at max.continuous speed : 303 [m/s]

propellor noise in flight : 105 [Db]

calculation : *1* (dimensions)

measured wing chord : 4.01 [m] at 50% wingspan

mean wing chord : 4.23 [m]

calculated average wing chord tapered wing with rounded tips: 4.21 [m]

wing aspect ratio : 7.7 []

seize (span*length*height) : 4668 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 37.6 [kg/hr]

fuel consumption(cruise speed) : 626.4 [kg/hr] (854.6 [litre/hr]) at 73 [%] power

distance flown for 1 kg fuel : 0.59 [km/kg] at 3555 [m] height, sfc : 321.5 [kg/kwh]

estimated total fuel capacity : 4826 [litre] (3537 [kg])

calculation : *3* (weight)

weight engine(s) dry with reduction gear : 2316.0 [kg] = 0.86 [kg/KW]

weight 317.0 litre oil tank : 26.95 [kg]

oil tank filled with 20.1 litre oil : 18.1 [kg]

oil in engine 15.0 litre oil : 13.4 [kg]

fuel in engine 18.3 litre fuel : 13.42 [kg]

weight 363.3 litre gravity patrol tank(s) : 54.5 [kg]

weight Burgess type silencers : 53.7 [kg]

weight NACA cowling 30.1 [kg]

weight variable pitch control : 35.1 [kg]

weight airscrew(s) incl. boss & bolts : 455.7 [kg]

total weight propulsion system : 2982 [kg](14.6 [%])

***************************************************************

fuselage aluminium frame : 2511 [kg]

cabin layout : pitch : 87 [cm] ( 2+2 ) seating in 8 rows

pax density : 1.21 [m2/pax]

weight two toilets : 16 [kg]

weight 4 fire extinguisher : 12 [kg]

weight pantry : 23.0 [kg]

weight garderobe : 16.5 [kg]

weight 18 windows : 16.2 [kg]

weight door : 5.0 [kg]

passenger cabin max.width : 3.31 [m] cabin length : 9.95 [m] cabin height : 1.90 [m]

weight cabin furbishing : 221.5 [kg]

weight cabin floor : 197.7 [kg]

pressure at cruise height : 0.59 [kg/cm2] cabin pressure : 0.77 [kg/cm2]

weight air pressurization system : 19.0 [kg]

fuselage covering ( 163.5 [m2] duraluminium 3.67 [mm]) : 1590.0 [kg]

fuselage (sound proof) isolation : 64.2 [kg]

weight radio transceiver equipment : 7.0 [kg]

weight artificial horizon : 1.1 [kg]

weight instruments. : 8.0 [kg]

weight lighting : 8.2 [kg]

weight electricity generator : 18.5 [kg]

weight controls : 11.2 [kg]

weight seats : 190.0 [kg]

weight air conditioning : 50 [kg]

total weight fuselage : 4908 [kg](24.0 [%])

***************************************************************

total weight aluminium ribs (247 ribs) : 728 [kg]

weight engine mounts : 134 [kg]

weight fuel tanks empty for total 4462 [litre] fuel : 357 [kg]

weight wing covering (painted aluminium 1.54 [mm]) : 1148 [kg]

total weight aluminium spars (multi-cellular wing structure) : 1276 [kg]

weight wings : 3152 [kg]

weight wing/square meter : 22.84 [kg]

cantilever wing without bracing cables

weight rubber de-icing boots : 35.9 [kg]

weight fin & rudder (12.4 [m2]) : 284.1 [kg]

weight stabilizer & elevator (15.5 [m2]): 355.6 [kg]

weight split flap (6.9 [m2]) : 81.8 [kg]

total weight wing surfaces & bracing : 4400 [kg] (21.5 [%])

*******************************************************************

Can only operate from paved runways

wheel pressure : 10210.0 [kg]

weight 2 Dunlop main wheels (1470 [mm] by 294 [mm]) : 616.2 [kg]

weight tailwheel(s) : 5.9 [kg]

weight hydraulic wheel-brakes : 18.4 [kg]

weight Dowty shock absorbers : 24.5 [kg]

weight wheel hydraulic operated retraction system : 78.5 [kg]

weight undercarriage with axle 433.5 [kg]

total weight landing gear : 1176.9 [kg] (5.8 [%]

*******************************************************************

********************************************************************

calculated empty weight : 13467 [kg](66.0 [%])

weight oil for 6.0 hours flying : 224.4 [kg]

calculated operational weight empty : 13692 [kg] (67.1 [%])

published operational weight empty : 13608 [kg] (66.6 [%])

weight crew : 405 [kg]

weight fuel for 2.0 hours flying : 1253 [kg]

weight catering : 57.5 [kg]

weight water : 23.0 [kg]

********************************************************************

operational weight empty: 15430 [kg](75.6 [%])

weight 33 passengers : 2541 [kg]

weight luggage : 403 [kg]

weight cargo : 1816 [kg]

operational weight loaded: 20190 [kg](98.9 [%])

fuel reserve : 229.9 [kg] enough for 0.37 [hours] flying

operational weight fully loaded : 20420 [kg] with fuel tank filled for 42 [%]

published maximum take-off weight : 20420 [kg] (100.0 [%])

calculation : * 4 * (engine power)

power loading (Take-off) : 7.61 [kg/kW]

power loading (operational without useful load) : 5.75 [kg/kW]

power loading (Take-off) 1 PUF: 10.14 [kg/kW]

total power : 2684.5 [kW] at 2300 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 5.7 [g] at 1000 [m]

limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.0 [g]

design flight time : 3.48 [hours]

design cycles : 6672 sorties, design hours : 23236 [hours]

operational wing loading : 1097 [N/m^2]

wing stress (3 g) during operation : 144 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -1.30 ["]

max. angle of attack (stalling angle) : 14.22 ["]

angle of attack at max. speed : 0.89 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° : 0.11 [ ]

lift coefficient at max. speed : 0.19 [ ]

lift coefficient at max. angle of attack : 1.32 [ ]

max.lift coefficient full flaps : 1.42 [ ]

induced drag coefficient at max.speed : 0.0019 [ ]

drag coefficient at max. speed : 0.0245 [ ]

drag coefficient (zero lift) : 0.0226 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW loaded : 19794 [kg]): 150 [km/u]

stalling speed at sea-level with full flaps (normal landing weight): 135 [km/u]

landing speed at sea-level (normal landing weight : 17065 [kg]): 155 [km/hr]

max. rate of climb speed : 165 [km/hr] at sea-level

max. endurance speed : 168 [km/u] min.fuel/hr : 316 [kg/hr] at height : 610 [m]

max. range speed : 290 [km/u] at cruise height : 5791 [m]

cruising speed : 368 [km/hr] at 3555 [m] (power:88 [%])

max. continuous speed : 377.32 [km/hr]

maximum speed : 387 [km/hr] at 1829 [m] (power:112 [%])

climbing speed at sea-level (loaded) : 385 [m/min]

climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 303 [m/min]

climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 108 [m/min]

calculation : *9* (regarding various performances)

take-off speed : 183.2 [km/u]

emergency/TO power : 1100 [hp] at 2543 [rpm]

static prop wash : 199 [km/u]

high wheel pressure, can only take off from paved runways

take-off distance at sea-level concrete runway : 304 [m]

take-off distance at sea-level over 15 [m] height : 412 [m]

landing run : 302 [m]

lift/drag ratio : 14.21 [ ]

climb to 1000m with max payload : 2.74 [min]

climb to 2000m with max payload : 5.56 [min]

climb to 3000m with max payload : 9.30 [min]

practical ceiling (operational weight empty 15430 [kg] ) : 7500 [m]

practical ceiling fully loaded (mtow- 30 min.fuel:20107 [kg] ) : 6000 [m]

calculation *10* (action radius & endurance)

published range : 1829 [km] with 5 crew and 3206.8 [kg] useful load and 88.1 [%] fuel

range : 917 [km] with 5 crew and 4760.0 [kg] useful load and 44.2 [%] fuel

range : 1983 [km] with 33.0 passengers with each 12.2 [kg] luggage and 95.5 [%] fuel

Available Seat Kilometres (ASK) : 65455 [paskm]

max range theoretically with additional fuel tanks total 9068.5 [litre] fuel : 4094 [km]

useful load with range 500km : 5795 [kg]

useful load with range 500km : 33 passengers

production (theor.max load): 2131 [tonkm/hour]

production (useful load): 1750 [tonkm/hour]

production (passengers): 12132 [paskm/hour]

combi aircraft mail/freight/passengers

oil and fuel consumption per tonkm : 0.31 [kg]

fuel cost per paskm : 0.055 [eur]

crew cost per paskm : 0.025 [eur]

economic hours : 12775 [hours] is less then design hours

time between engine failure : 396 [hr]

can continue fly on 3 engines, low risk for emergency landing for PUF

writing off per paskm : 0.072 [eur]

insurance per paskm : 0.003 [eur]

maintenance cost per paskm : 0.138 [eur]

direct operating cost per paskm : 0.293 [eur]

direct operating cost per tonkm (max. load): 1.666 [eur]

direct operating cost per tonkm (normal useful load): 2.028 [eur]

33 pax layout

Literature :

Piston-engined airliners page 42,44,45

Praktisch handboek vliegtuigen deel 5 page 25,26,27

Jane’s fighting aircraft WWII page 211

Jane’s all the world aircraft 1938 page 253c

Boeing 307 Stratoliner - Wikipedia

Nieuwe Haarlemsche Courant | 20 maart 1939 | pagina 2 - Krantenviewer Noord-Hollands Archief

Boeing 307 Stratoliner (aviation-history.com)

Boeing 307 Stratoliner "Clipper Flying Cloud" | National Air and Space Museum (si.edu)

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/

content please mail to below mail address

(c) B van der Zalm 22 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4

notes :