~conceptual design -...
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Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
DR. ZAMRI BIN OMARDepartment of Aeronautical Engineering
Faculty of Mechanical & Manufacturing Eng.
Email : [email protected] : 4537618
Room: C08-01Mobile : 0127220907 (text only!!)
Congratulations…Welcome to UTHMPARIT RAJA….A Place To Be..
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~Conceptual Design
7 Pivot Points in Conceptual Design
� 1. Requirements
� 2. Airplane weight ~ First estimation
� 3. Critical performance parameters
� 4. Configuration layout
� 5. Airplane weight ~ Better estimation
� 6. Performance analysis
� 7. Optimization
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
Conceptual Design ~1) Requirements
� Requirements for a new airplane are unique.
� Generally, for any new airplane design;
motivated by some established requirements
� RFPs by stakeholders, govts, military, etc..
� Customer request.
� Most GAs ~new design set by manufacturers.
� GAs ~ manufactures really studied their
customer needs.
� You, as the potential aircraft designer &
manufacturer ~ is given with this RFP
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
Conceptual Design ~ A Case Study
Design of A Propeller-Driven Airplane
2
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� To design a light, business transport aircraft, pressurized cabin.
� Max level speed at midcruise weight : 250 mi/hr
� No. of passengers : 5 (+pilot)
� Range : 1200 miles.
� Ceiling : 25,000 ft.
� Rate of Climb at sea level: 1,000 ft/min.
� Stalling speed : 70 mi/h.
� Landing distance (to clear 50 ft obstacle) : 2,200 ft.
� Takeoff distance (to clear 50 ft obstacle) : 2,500 ft.
~(1) The Requirement
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� Wc : crew weight (pilots, cabin crews)
� Wp : payload weight. Passengers, luggage, fright, etc..
� Wf : fuel weight.
� We : empty weight. Airframe, engines, avionics, systems, equipments, etc..
~(2) Weight ~1st Estimation
� The takeoff gross weight, Wo;
efpco WWWWW +++=
)W/W(W/W(1
WW
oe)of
pc
−−
+= -------------------------(1)
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� (2.1) Estimation of We/Wo
� Evolutionary of previous existing airplanes � A New Airplane
� Needed : historical, statistical data of previous airplanes (parametric study)
� airplanes from 1930 - 2000Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� For our 1st
estimate, we
choose;
62.0W
W
o
e =
3
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� (2.2) Estimation of Wf/Wo
� Statistics;
Airplane (L/D)max
Cessna 310 13
Beach Bonanza 13.8
Cessna Cardinal 14.2
� Reasonable approx for our
airplane � (L/D)max = 14
� Use Brequet’s range eqn;
159.0)W/W1(06.1W
Wo5
o
f =−= -------------(2)3
2p
W
Wln
D
L
cR
η=
� Based on mission profile;
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� (2.2) Calculation of Wo and Wf
� One-crew airplane � Wc = 170 lb
� Payload; 5 passengers + 20lb baggage per person + pilot baggage;
� � Wp = 5(170)+20(6) = 970 lb.
� From Eqn. (1)
� See the 4.525 amplification factor !
� From eqn (2),
� Weight of avgas is 5.64 lb/gal. So the tank vol should be;
Tank volume = 820 lb/5.64 = 145.4 gal = 661 litres ?
lb 158,5)525.4( 140,10.62-0.159-1
970170W
)W/W(W/W(1
WWo
oe)of
pc==
+==
−−
+
lb. 820lb) (5,158 159.0W159.0W159.0W
Wof
o
f ===⇒=
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (CL)max, (L/D)max, W/S and T/W
� (3.1) Estimation of (CL)max
� Select the wing’s airfoil shape.
� Airfoil data : NACA, Clark, RF, Gottingen, Worthman, etc..
http://www.ae.illinois.edu/m-selig/ads/coord_database.html
� Many GA aircrafts use different airfoils at root and tip.
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.1) Estimation of (CL)max
� We choose ;
� at root : NACA 23018
� at tip : NACA 23012
� Average (Cl)max;
1.7
2
8.16.1)Cl( max
=
+=
4
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.1) Estimation of (CL)max
� To aid TO & Landing; add TE flaps � simple plain flap.
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.2) Estimation of (CL)max
� To aid TO & Landing; add TE flaps � simple plain flap.
� When flap deflected 45o �
� Average (Cl)max with 45O flap deflection =1.7 + 0.9 = 2.6
� To account 3D effect of finite wing, Raymer suggests (for AR >5);
�
9.0)Cl( max =∆
2.34
) (2.6 0.9
(Cl) 9.0)CL( maxmax
=
=
=
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
� Here what STOL airplane can do !
~ 2009 STOLcompetition
~ Land & TO on a hill
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.2) Estimation of (L/D)max
� Statistics;
Airplane (L/D)max
Cessna 310 13
Beach Bonanza 13.8
Cessna Cardinal 14.2
� Reasonable approx for our
airplane � (L/D)max = 14
5
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.3) Estimation of wing loading, (W/S)
� W/S affects Vstall, Vmax, RoC, TO & LND distance, turn performance.
�
�
�
�
�
�
�
� FAR 23 : Vstall ≤ 61 kts ( mi/h = km/h)
⇒ρ
=∞ maxL
stall)C(
1
S
W2V -------------(3)maxL
2stall
)C(V2
1
S
W∞ρ=
0,D
0,D2
maxAmaxAmax
C
KC4]W/)T[(S/W](W/)T[(V
∞ρ
−=
-------------(4)
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.3) Estimation of wing loading, (W/S)
� Required; Vstall ≤ 70 mi/h = 102.7 ft/s, ρ∞=0.002377 slug/ft3 (SL)
�
�
�
�
� This W/S is constrained by stall speed.
� How about W/S constrained by landing distance ?
⇒
ρ=
∞ maxLstall
)C(
2
S
W2V -------------(3)maxL
2stall
)C(V2
1
S
W∞ρ=
223 lb/ft 3.29)34.2()ft/s 7.102)(ft/slug 002377.0(2
1
S
W==
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.3) Estimation of wing loading, (W/S)
� W/S constrained by landing distance.
�
�
�
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.3) Estimation of wing loading, (W/S)
� Flight path radius during flare;
� Vf is average flare velocity, Vf=1.23Vstall
�
� Flare height is given by,
� Approach angle is assumed θa=3o for transport aircraft.
�
� Approach distance to clear 50 ft obstacle,
�
� Flare distance,
ft 477,2ft/s 2.32x2.0
ft/s) 7.102x23.1(
g2.0
VR
2
22f ===
ft 4.3)3 cos1(477,2) cos1(Rho
af =−=θ−=
ft 8893tan
ft 4.350
tan
h50S
oa
fa =
−=
θ
−=
ft 1303sin 2,477 sinRSo
af ==θ=
6
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.3) Estimation of wing loading, (W/S)
� At SL, the total ground roll can be approximated as ;
�
� Required : 2,200 ft landing distance,
� From eq. (5),
�
�
� This W/S is greater than Vstall constrained W/S (29.3 lb/ft2).
� Look !, if W/S < 41.5 lb/ft2, we’ll obtain shorter landing distance (<2,200 ft)
� So we choose, W/S = 29.3 lb/ft2
S
W46.18
S
W4.65Sg +=
afgL SSSS ++=
ft 181,1889130200,2SSSS afLg =−−=−−=
-------------(5)
2lb/ft 5.41S
W
S
W46.18
S
W4.65 ft 181,1 =⇒+=
Zamri Omar, UTHM
Design of A Propeller-Driven Airplane ~Conceptual Design
~(3) Estimation of Critical Performance Parameters
� (3.4) Estimation of thrust-to-weight ratio, (T/W)
� T/W affects TO distance, RoC, Vmax
� To obtain the design value of (T/W), need to examine the effect of each
constraint on (T/W).
� Based on TO distance constraint, Total power needed, P ≥ 118.8 hp
� Based on RoC constraint, Total power needed, P ≥ 362.5 hp
� Based on Vmax constraint, Total power needed, P ≥ 303.1 hp
� So to satisfy all requirements, the engine should capable of producing max
power of 362.5 hp or greater.
� Power-to-Weight ratio,
�
� In term of power loading,
�
� (W/P)=14 is typical for GA (Raymer). So ours is very good !
lb/hp07.0lb 5,158
hp 5.362)W/P( ==
lb/hp 3.14hp 362.5
lb 158,5)P/W( ==