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Fuselage Size and kN for known speed and altitude and MTOW

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Fuselage Size and kN for known speed and altitude and MTOW

Old 16th Sep 2023, 11:48
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Fuselage Size and kN for known speed and altitude and MTOW

How doth the kN for a set speed change when the size m2 of the fuselage changes though the wingspan (say 14metre) and wing fixed.

Say circular and square and rectangular fuselage section.

Say fuselage diameter 1.5metre, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1. 2.2, 2.3., 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2metre

Say fuselage nose cone for M0.7-M1.5.

Say set speed 400kts 500kts 600kts 700kts 800kts 900kts 1000kts (M0.7-M1.5)

Say altitudes 500ft 1000ft 2000ft 3000ft 4000ft 5000ft....42000ft

Say MTOW 10,000kg 15,000kg 20,000kg 25,000kg 30,000kg 35,000kg

Experience range 30kN-300kN though what the experience and what the calc.

Say 2.5m square centre fuselage, 14m span, 0.3thick wing, cruise at M0.7 M0.8 M0.9 M1.0 M1.1 M1.2 M1.3 M1.4 M1.5
each altitude
each MTOW

what kN to maintain each speed

Say 3.8m square centre fuselage, 14m span, say 0.3metre thick wing root-tip, cruise at M0.7 M0.8 M0.9 M1.0 M1.1 M1.2 M1.3 M1.4 M1.5
each altitude
each MTOW

what kN to maintain each speed

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Old 18th Sep 2023, 15:07
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I suppose you mean drag (=thrust) in kN? I would suggest getting hold of something like this: https://amzn.to/3sVG8Fs and doing a bit of reading.
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Old 19th Sep 2023, 17:00
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kN for chosen Airspeed at different Altitudes with these MTOW

Adding this from the other thread was writing since this pertaining to the same airplane

What kN each MTOW (10,000kg, 15,000kg, 20,000kg, 25,000kg, 30,000kg, 35,000kg) with each Altitude (500ft to 42,000ft in 1000ft increments) to attain each speed (stall to 1200kts at each altitude in 100kts increments)

(They say cruise Thrust = cruise Drag Fd = 0.5 x rho (air density with altitude kg/m3) x A (alleged drag area (m2)) x (speed (m/s) x speed (m/s) at each altitude) and get a number, though doth that equate to the experience of each designing and flying airplanes when calc for req'd kN for cruise and kN for any task, else find Rolls Royce and Pratt and Witney and colleagues brochures available engines with fuel consumption and buy those though how to choose).

(Have done the Fd = 0.5 p A v2 calc, obtained ISA air density with altitude in kg/m3, obtained different possible flat-plate fuselage (yet to add wing etc) metre2, considered Mach 0.7-1.5 in 0.1 increments (M0.7 M0.8 M0.9 M1.0 M1.1 M1.2 M1.3 M1.4 M1.5) thence m/s equivalent speed at Sea Level and 40,000ft (have air density and speed of sound alleged for each altitude hence could consider any of those alleged altitudes kg/m3) , did the numbers, and could thence consider (density-)altitude for each chosen speed if with fixed alleged cruise kN (unknown engine)) though, what the truth in the experience of the TP FTE and aero eng and those that choose the engine and kN of each airplane (kN varied with altitude air density and speed).)

(Useful to know ISA allege that at 2,000ft altitude 1m3 (10 lots of 10cmthick x 1m x 1m of ISA air at 2,000ft weighs 1.0 kg/m3 hence same as 1kg water (0.001m3, 10cm x 10cm x 10cm H20 water) at 15-25degC Sea Level. The air holds the 1m3 air up, hence....could hold airplane up....buoyancy....
If catch 1m3 (ISA air at 2000ft) (= 1kg Sea Level 15-25degC water) x 10,000 (under wings) thence could buoyancy 10,000kg airplane, hence tweak speed (and fiddling factor) catch enough ISA 2,000ft air with that speed (rate of getting 10,000 lots of 1m3 2,000ft ISA air under wings and fuselage) thence buoyancy of airplane.
If 1m3 = 10cmthick (bound ar y layer) x 1m x 1m and wing and fuselage size = such and such m2 thence tweak speed until MTOW equals weight of air under each wing each / (U NIT) time.
Say wing 10m wingspan wing of 1m chord, zero fuselage (why complicate this), 10m wingspan 1m width chord, hence 10 x (10cm x 1m x 1m = 1m3) = 10m3 air density under wing = kg/m3 = 10,000, hence what rate buoyancy on MTOW (kg) equivalent to get a 1,000 of those quickly enough, thence airplane buoyant sitting on 10m3 x 1000 of ISA 2,000ft air, thence what rate (speed) to equate MTOW with air under wing hence buoyancy (and they say airship displace relevant m3 of air hence buoyancy).
Simple Aero Degree calc for lift of any airplane calc if could say what rate of getting air under the wings (as if solid air and of buoyancy mass equivalent to MTOW, parameter the rate of getting the air hence the speed) and what fiddle factor since they only want fiddle factors that need expensive equipment and tests jobs work economy to get answer they dont tell others.
Wing hold airplane up
Air hold airplane up
Hold displacement m3
Wing sit on equivalent density of wing, MTOW 12,000kg on equivalent 12,000kg density medium hold MTOW up
Wing sit on reduced density (air) MTOW 12,000kg sit on 12,00kg equivalent-density air hold MTOW up what rate of getting that air (Airspeed)(and vector if relevant) hence equivalent buoyancy
= Airspeed with each Altitude (Air Density) for each MTOW to stay up by buoyancy. Then compare with (above-wing relative-Vacuum and other) alleged Lift, and see if effects, glide slopes, drag, wing design, ....
ISA 2,000ft EartHA I.R. dens it y 1.0kg each 1m3 (10cm x 1m x 1m) = 1kg (10cm x 10cm x 10cm) non-saline 15-25degC water at sea level.

Twas writing of vibration in another thread for the same Airplane

They say that vibration with low-level flying is significant (and consider air turbulence/movement normal to the trajectory of the airframe)

They say that a narrow (short chord) thin (high aspect ratio) wing is the choice when low-level flying since that reduces vibration experienced by the pilot and airframe (less wing for the (vector normal relative to trajectory of the airframe) air to grab), though the centre fuselage oscillates with the length of those (aspect ratio) long narrow (short chord) wings (with without damping and vibration with engines, fuel), and ALLEGED less skin friction with short chord (though longer span).

The Panavia Tornado shifts from low aspect ratio wing swept (say around 8.5m span) to relatively high aspect ratio narrow-chord wing spread (say around 14m span) when low-level flying at relevant speeds, and one of the reasons is reducing vibration experienced by the pilots and(ing) the airframe and loads (catch less air to buffet wing thence transmit less vibration, and vibration filter-amplifier). And the weight of the centre fuselage then oscillates relative to the wingtips, from hugging low aspect ratio wings, to wings spread wide, different vibration amplitude and phase and frequency spectra of centre load relative to different spans (and structures), and with without wing fuel engines loads.

If a design doesnt want to use a long narrow (short chord) wing and instead wants to use a short (say 14m wingspan) solid (could be louvre) wing that gets 90-120m2, those designing want consider whether the vibration significant, without having that wing available to test thus-far.

If, say, flying that at 300kts low level acceptable, though 500kts low level teeth digestive system jarring, and the transition from 378-423kts hence saying what that wing choice thence what flying (lack of)qualities, who can say, from experience.

Hence, say, if a 14m wingspan 0.3m thick solid wing of 90-120m2, say 1 ton load each wing tip, 5m tip chord, say around 11-12m root chord, flying low-level, centre fuselage jet/rocket propulsion, stall-->1200kts low level, what the vibration experienced by the pilot, crew, those in the airplane, and the airframe, and hence what that wing arrangement (lack of) flying qualities hence choice.
Is Calvin & Hobbes Calvin on loads of Cereal Sugar Caffeine trying to read instruments else calm (though Airframe on Caffeine too much Sugar) else... all smooth at 400kts 30ft altitude 500kts 600kts 700kts 800kts 900kts 1000kts 1100kts 1200kts

How does Aspect Ratio, wing shape and span and m2 (ft2), and thickness, relate to acceptable and non-acceptable, comforting and noncomforting, tolerable and non-tolerable, smooth, terrible, vibration (Amplitude and Spectra), at relevant altitudes and speeds, hence those that design (nonstandard) airplane get a feel of that at the start.

What are pilot and TP and FTE experiences with each airplane, and preferences of airplane (and airfoil). What are aero eng and structural calc design experiences methods.
They say (wood and metal) DeHavilland Vampire smooth and long glide though semi low aspect ratio at 300-450kts low level.
They say Blackburn Buccaneer preferable to Panavia Tornado if low level flying.

What was asked was, say
MTOW 10,000kg 15,000kg 20,000kg 25,000kg 30,000kg 35,000kg
Wing fixed 14m span (and consider fixed16m span and fixed 18m span max) and thick 0.3m and need 90-120m2 if effective enough with lift and tight turns/moshing-flight and MTOW
Relatively low Aspect Ratio (14m span), 5m tip chord (can consider 4m tip chord), say around 11-12m root chord (and those that want say, which has more drag, equivalent 90-120m2 long high-aspect-ratio narrow short-chord wing or 14m relatively low-aspect-ratio wing of 11-12m root chord)

(Isn't mushing flight. It moshing flight, like when front lot of audience head bang and jump and dance at music gig, moshing)

Velocities from stall to 1200kts (100kt increments) at all altitudes (0-42,000ft (from 500ft in 1000ft increments))

Say +/- 6g and fully aerobatic (and could consider the +9g -2g norm)

Altitudes (each choice of kts from stall to 1200kts at each altitude) from 500ft to 42,000ft in 1,000ft increments

Structural and Exterior Material Wood (natural wood, plywood, Duramold), else Carbon Fibre Composite, else Metal

Wing Tip with fixed (here on Pprune website unspecified) load (say each wingtip 1 ton)

Centre fuselage jet/rocket engine(s) though consider any relevant propulsion method,

Consider centre fuselage propulsion, and pilot TP FTE and aero experience of airplane with wing-mount engines and fuselage-mount engines, and preferences, feelings, of airfoil, wing shape, (with MTOW and speed and altitude), and which pleasure to fly and which teeetttthhhhdddiiigggeesssttttiivvveeessyyysstteemmmjjjjjaaa rrrrinnng

Haven't any money for responses hence consider

Did work at Boscombe Down some while ago, so could use their flim flam lingo if obliged (12,375 rounds of report signing (FIRE DOFF) before DESIRABLE and ESSENTIAL released when could have done it all in 30.327 secs), though colloquial here
ChrisAirplane is offline  

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