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weight and performance calculations for the Benoist XIV

Afbeeldingsresultaat voor Benoist XIV

Benoist XIV

importance : ***

first flight : operational : 1 January 1914

country : United States of America

design : Thomas Benoist

production : 2 aircraft

general information :

On 1 January 1914 the world first scheduled airline service was opened with a heavier-than-air craft. A small Benoist flying boat, named “Lark of Duluth”, piloted by Roger Jannus flew between Tampa and St.Petersburg in Florida, a distance of 34.5 km and taking 1 passenger on each trip. At the first flight the major of St.Petersburg Abraham C. Pheil . The line was profitable, a 2 nd Benoist XIV with the name “Florida” was taken in service. However in April 1914, subsidies ceases, the end of the tourist season and the Mexican war ended the airline operations. In those few months 1205 passengers were carried over 17702 km.

users : Percival E. Fansler’s St.Petersburg – Tampa Airboat Line

crew : 1 passengers : 1

engine : 1 Roberts 6-X liquid-cooled 6 -cylinder inline engine 75 [hp](55.9 KW)

dimensions :

wingspan : 13.41 [m], length : 7.93 [m], height : 2.8[m]

wing area : 41.0 [m^2]

weights :

max.take-off weight : 800 [kg]

empty weight operational : 567 [kg] useful load : 100 [kg]

performance :

maximum speed :103 [km/hr] at sea-level

cruise speed :93 [km/u] op 100 [m]

service ceiling : 1500 [m]

range : 200 [km]

description :

3-bay biplane flying boat

2 (aid) tip floats

two spar upper and lower wing

engine in fuselage drives pusher propellor by chain

Afbeeldingsresultaat voor Benoist XIV

airscrew :

fixed pitch 2 -bladed pusher airscrew with max. efficiency :0.62 [ ]

diameter airscrew 3.05 [m]

angle of attack prop : 12.23 [ ]

fine pitch

reduction : 0.90 [ ]

airscrew revs : 1102 [r.p.m.]

pitch at Max speed 1.56 [m]

blade-tip speed at Vmax and max revs. : 178 [m/s]

calculation : *1* (dimensions)

measured wing chord : 1.63 [m]

mean wing chord : 1.53 [m]

calculated wing chord (square tips): 1.55 [m]

wing aspect ratio : 8.77 []

estimated gap : 1.73 [m]

gap/chord : 1.13 [ ]

seize (span*length*height) : 298 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 2.5 [kg/hr]

fuel consumption(cruise speed) : 16.1 [kg/hr] (22.0 [litre/hr]) at 81 [%] power

distance flown for 1 kg fuel : 5.74 [km/kg] at 750 [m] cruise height, sfc : 358.2 [kg/kwh]

estimated total fuel capacity : 53.91 [litre] (39.52 [kg])

calculation : *3* (weight)

weight engine(s) dry : 125.0 [kg] = 2.24 [kg/KW]

weight reduction gear : 2.8 [kg]

weight 8.7 litre oil tank : 0.74 [kg]

oil tank filled with 0.4 litre oil : 0.4 [kg]

oil in engine 3.1 litre oil : 2.8 [kg]

fuel in engine 0.4 litre fuel : 0.28 [kg]

weight 9.4 litre gravity patrol tank(s) : 1.4 [kg]

weight radiator : 8.0 [kg]

weight exhaust pipes & fuel lines 6.9 [kg]

weight cowling 2.2 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 20.6 [kg]

total weight propulsion system : 173 [kg](21.6 [%])

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fuselage skeleton (wood gauge : 5.18 [cm]): 55 [kg]

fuselage width : 1.12 [m]

cabin layout : pitch : 87 [cm] (1+1) seating

bracing : 3.8 [kg]

plywood/wood covering hull (gauche : 1.4 [cm]): 110 [kg]

Percival E. Fansler, Mayor Abraham C. Pheil, and Antony H. Jannus with the Benoist Type XIV flying boat Lark of Duluth, 1 January 1914. (Florida State Archives, Florida Memory)

Percival E. Fansler, Mayor Abraham C. Pheil, and Tony Jannus , the younger brother of Roger Jannus , with the Benoist Type XIV flying boat Lark of Duluth, 1 January 1914. (State Archives of Florida, Florida Memory)

weight instruments. : 1.1 [kg]

weight lighting : 1.1 [kg]

weight controls : 4.9 [kg]

weight seats : 6.0 [kg]

weight 45 [litre] main fuel tank empty : 3.6 [kg]

weight engine mounts & firewalls : 3 [kg]

total weight fuselage : 188 [kg](23.5 [%])

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weight wing covering (doped linen fabric) : 37 [kg]

total weight ribs (43 ribs) : 48 [kg]

load on front upper spar (clmax) per running metre : 499.4 [N]

Afbeeldingsresultaat voor Benoist XIV

load on rear upper spar (vmax) per running metre : 159.9 [N]

total weight 8 spars : 50 [kg]

weight wings : 135 [kg]

weight wing/square meter : 3.29 [kg]

weight 12 interplane struts & cabane : 24.8 [kg]

weight cables (93 [m]) : 7.3 [kg] (= 79 [gram] per metre)

diameter cable : 3.6 [mm]

weight fin & rudder (2.1 [m2]) : 7.2 [kg]

weight stabilizer & elevator (3.9 [m2]): 13.2 [kg]

total weight wing surfaces & bracing : 187 [kg] (23.4 [%])

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weight 2 tip floats : 11 [kg] (1.4 [%])

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calculated empty weight : 560 [kg](70.0 [%])

weight oil for 2.6 hours flying : 6.5 [kg]

weight cooling fluids : 12.1 [kg]

calculated operational weight empty : 578 [kg] (72.3 [%])

published operational weight empty : 567 [kg] (70.9 [%])

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weight crew : 81 [kg]

St. Petersburg-Tampa Airboat Line timetable. (Smithsonian Institution National Air and Space Museum)

weight fuel for 2.0 hours flying : 32 [kg]

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operational weight empty: 692 [kg](86.5 [%])

weight 1 passengers : 77 [kg]

weight luggage & freight : 23 [kg]

operational weight loaded: 792 [kg](86.5 [%])

fuel reserve : 7.2 [kg] enough for 0.45 [hours] flying

possible additional useful load : 1 [kg]

operational weight fully loaded : 800 [kg] with fuel tank filled for 100 [%]

published maximum take-off weight : 800 [kg] (100.0 [%])

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calculation : * 4 * (engine power)

power loading (Take-off) : 14.30 [kg/kW]

power loading (operational without useful load) : 12.37 [kg/kW]

total power : 55.9 [kW] at 1225 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 2.0 [g] at 1000 [m]

limit load : 3.5 [g] ultimate load : 5.2 [g] load factor : 2.3 [g]

design flight time : 1.73 [hours]

design cycles : 579 sorties, design hours : 1000 [hours]

operational wing loading : 165 [N/m^2]

wing stress (3 g) during operation : 151 [N/kg] at 3g emergency manoeuvre

Afbeeldingsresultaat voor Lark of Duluth

calculation : *6* (angles of attack)

angle of attack zero lift : -1.14 ["]

max. angle of attack (stalling angle) : 11.91 ["]

angle of attack at max. speed : 2.67 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° :0.10 [ ]

lift coefficient at max. angle of attack : 1.14 [ ]

lift coefficient at max. speed : 0.33 [ ]

induced drag coefficient at max. speed : 0.0072 [ ]

drag coefficient at max. speed : 0.0590 [ ]

drag coefficient (zero lift) : 0.0518 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW): 55 [km/u]

stalling speed at sea-level (MTOW): 60 [km/u]

landing speed at sea-level: 65 [km/hr]

min. drag speed (max endurance) : 65 [km/hr] at 750 [m](power :46 [%])

min. power speed (max range) : 74 [km/hr] at 750 [m] (power:51 [%])

max. rate of climb speed : 64.4 [km/hr] at sea-level

cruising speed : 93 [km/hr] op 750 [m] (power:73 [%])

design speed prop : 98 [km/hr]

maximum speed : 103 [km/hr] op 100 [m] (power:99 [%])

climbing speed at sea-level : 149 [m/min]

Afbeeldingsresultaat voor Lark of Duluth

calculation : *9* (regarding various performances)

take-off speed : 71.5 [km/u]

static prop wash : 89 [km/u]

take-off distance at sea-level : 78 [m]

lift/drag ratio : 8.65 [ ]

climb to 1000m with max payload : 11.39 [min]

climb to 2000m with max payload : 30.40 [min]

climb to 3000m with max payload : 63.24 [min]

published ceiling (1500 [m]

practical ceiling (operational weight) : 4068 [m] with flying weight :692 [kg] line 3385

practical ceiling fully loaded (mtow- 30 min.fuel) : 3328 [m] with flying weight :792 [kg]

max. dive speed : 235.1 [km/hr] at 2328 [m] height

turning speed at CLmax : 76.9 [km/u] at 50 [m] height

turn radius at 50m: 28 [m]

time needed for 360* turn 8.3 [seconds] at 50m

load factor at max. angle turn 1.92 ["g"]

calculation *10* (action radius & endurance)

published range : 200 [km] with 1 crew and 105.8 [kg] useful load and 88.1 [%] fuel

range : 233 [km] with 1 crew and 100.0 [kg] useful load and 102.8 [%] fuel

max range theoretically with additional fuel tanks for total 191.8 [litre] fuel : 807.8 [km]

useful load with range 500km : 54 [kg]

production : 4.97 [tonkm/hour]

oil and fuel consumption per tonkm : 3.76 [kg]

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Literature :

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 05 February 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4