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weight and performance calculations for the REP Monoplane Type N
Minister of War Alexandre Millerand inspects a REP monoplane September 2012 at Velizy-Villacoublay
REP Monoplane Type N
role : two-seat unarmed reconnaissance
importance : ***
first flight : Summer 1912 operational : September 1912
design : Robert Esnault-Pelterie
country : France
production : approximately 30 pieces
general information:
This medium-wing monoplane was a military version of the famous monoplane that Robert Esnault-Pelterie built in 1909. It served until the 1st month of 1915 in 2 French squadrons REP 15 and REP 27. REP 15 aircraft carried out reconnaissance missions during the battle of Charleroi in August 1914. On March 2, 1915, one of them attacked an Aviatik near Lanevin and shot it down with shots from the observer's carbine. The French had the type N in use, The English Navy flew with 12 Type L Pararsols, they had a high-placed wing.
Steering was done by distorting the wing (wing warping)
crew : 2
main users : France, Turkey
armament : no fixed armament
engine : 1 Gnome 7A Monosoupape air-cooled 7 -cylinder Monosoupape rotary engine 80 [hp](58.8 KW)
dimensions :
wingspan : 9.2 [m], length : 6.6 [m], height : 2.66[m]
wing area : 13.5 [m^2]
weights :
max.take-off weight : 495 [kg]
empty weight operational : 270 [kg] bombload : 0 [kg]
performance :
maximum speed : 116 [km/hr] at sea-level
service ceiling : unknown
endurance : 1.5 [hours]
estimated action radius : 78 [km]
description :
shoulder-winged monoplane with fixed landing gear and tail strut
two spar wing
engines, landing gear, fuel and bombs in or attached to the fuselage
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.62 [ ]
estimated diameter airscrew 2.45 [m]
angle of attack prop : 15.60 [ ]
reduction : 1.00 [ ]
airscrew revs : 1200 [r.p.m.]
pitch at Max speed 1.61 [m]
blade-tip speed at Vmax and max revs. : 157 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.47 [m]
calculated wing chord (rounded tips): 1.86 [m]
wing aspect ratio : 6.27 []
gap : 0.00 [m]
gap/chord : 0.00 [ ]
seize (span*length*height) : 162 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 6.5 [kg/hr]
fuel consumption(cruise speed) : 19.3 [kg/hr] (26.3 [litre/hr]) at 79 [%] power
distance flown for 1 kg fuel : 5.42 [km/kg]
estimated total fuel capacity : 45 [litre] (33 [kg])
calculation : *3* (weight)
weight engine(s) dry : 109.4 [kg] = 1.86 [kg/KW]
weight 14 litre oil tank : 1.8 [kg]
oil tank filled with 0.4 litre oil : 0.4 [kg]
oil in engine 0 litre oil : 0.3 [kg]
fuel in engine 0 litre fuel : 0.3 [kg]
weight 11 litre gravity patrol tank(s) : 1.1 [kg]
weight cowling 2.4 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 13.5 [kg]
total weight propulsion system : 127 [kg](25.7 [%])
***************************************************************
fuselage skeleton (wood gauge : 3.78 [cm]): 24 [kg]
houtdikte wordt erg dun !!!!!
bracing : 1.1 [kg]
fuselage covering ( 8.2 [m2] doped linen fabric) : 2.6 [kg]
weight controls + indicators: 5.5 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 34 [litre] main fuel tank empty : 3.2 [kg]
weight engine mounts & firewalls : 3 [kg]
total weight fuselage : 51 [kg](10.2 [%])
***************************************************************
weight wing covering (doped linen fabric) : 9 [kg]
total weight ribs (28 ribs) : 29 [kg]
load on front upper spar (clmax) per running metre : 302.5 [N]
load on rear upper spar (vmax) per running metre : 153.2 [N]
total weight 4 spars : 15 [kg]
weight wings : 53 [kg]
weight wing/square meter : 3.91 [kg]
weight cables (37 [m]) : 4.5 [kg] (= 122 [gram] per metre)
diameter cable : 4.5 [mm]
weight fin & rudder (1.0 [m2]) : 4.0 [kg]
weight stabilizer & elevator (1.5 [m2]): 6.0 [kg]
total weight wing surfaces & bracing : 67 [kg] (13.6 [%])
*******************************************************************
weight armament : 0 [kg]
********************************************************************
good soft ground capabilities
wheel pressure : 247.5 [kg]
weight 2 wheels (720 [mm] by 85 [mm]) : 14.7 [kg]
weight tailskid : 0.8 [kg]
weight undercarriage with axle 6.5 [kg]
total weight landing gear : 22.0 [kg] (4.5 [%]
*******************************************************************
REP type N at St.Dizier, 24 August 1913 – photo Delcampe
********************************************************************
calculated empty weight : 267 [kg](54.0 [%])
weight oil for 1.8 hours flying : 11.7 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 280 [kg] (56.6 [%])
published operational weight empty : 270 [kg] (54.5 [%])
---o---
"
weight crew : 162 [kg]
weight fuel for 1.5 hours flying : 29 [kg]
********************************************************************
operational weight : 471 [kg](95.2 [%])
bombload could not be carried with fuel for 2 hours flying time
weight camera : 20 [kg]
operational weight photo mission : 491 [kg]
fuel reserve : 4 [kg] enough for 0.20 [hours] flying
possible additional useful load : 0 [kg]
operational weight fully loaded : 495 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 495 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 8.01 [kg/kW]
total power : 58.8 [kW] at 1200 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.2 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.5 [g]
design flight time : 1.20 [hours]
design cycles : 242 sorties, design hours : 290 [hours]
operational wing loading : 357 [N/m^2]
wing stress (3 g) during operation : 274 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.25 ["]
max. angle of attack (stalling angle) : 12.93 ["]
angle of attack at max. speed : 5.53 ["]
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 : 0.54 [ ]
induced drag coefficient at max. speed : 0.0200 [ ]
drag coefficient at max. speed : 0.1305 [ ]
drag coefficient (zero lift) : 0.1105 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 80 [km/u]
landing speed at sea-level (OW without bombload): 96 [km/hr]
min. drag speed (max endurance) : 92 [km/hr] at 1000 [m](power :61 [%])
min. power speed (max range) : 92 [km/hr] at 1000 [m] (power:61 [%])
cruising speed : 104 [km/hr] op 1000 [m] (power:74 [%])
design speed prop : 110 [km/hr]
maximum speed : 116 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 204 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 207 [m]
lift/drag ratio : 5.78 [ ]
max. practical ceiling : 4500 [m] with flying weight :370 [kg]
practical ceiling (operational weight) : 2975 [m] with flying weight :471 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 2900 [m] with flying weight :476 [kg]
published ceiling (0 [m]
climb to 1500m (without bombload) : 8.77 [min]
max. dive speed : 243.6 [km/hr] at 1900 [m] height
load factor at max. angle turn 1.44 ["g"]
turn radius at 500m: 76 [m]
time needed for 360* turn 17.2 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 0.15 [hours] with 2 crew and 50 [kg] useful (bomb)load and 8.7 [%] fuel
published endurance : 1.50 [hours] with 2 crew and possible useful (bomb) load : 24 [kg] and 88.1 [%] fuel
action radius : 89 [km] with 2 crew and 20[kg] photo camera or bombload
max range theoretically with additional fuel tanks for total 184 [litre] fuel : 732 [km]
useful load with action-radius 250km : 43 [kg]
production : 4.47 [tonkm/hour]
oil and fuel consumption per tonkm : 5.76 [kg]
I--°°=/
°
literature :
praktisch handboek vliegtuigen deel 1 page 162
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 23 March 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4
notes :
There is not to much information on internet and in the literature regarding weight and dimensions. Dimensions are deducted from the 3-view drawing and MTOW is a estimation based on the empty weight + 2 crew + fuel for 1.5 hrs