AE-705: Introduction to Flight GLIDING CLIMBING CEILING Udit Vohra Aerospace Engineering Department PEC University of Technology, Chandigarh AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Layout Gliding Flight • Climbing flight • Operative Ceilings • AE-705 Introduction to Flight Lecture No. 13 Chapter-07
GLIDING FLIGHT AE-705 Introduction to Flight Lecture No. 13 Chapter-07
What is gliding flight ? Art of silent flight Flight without any Thrust Forces involved in gliding flight Horizontal θ W θ Smallest value of θ gives the flattest glide AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Range in a Glide Range = distance traversed by an aircraft • Range when θ or ( L D) max AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Sink Rate during Glide Sink Rate = rate of reduction in altitude = dh • dt Min. sink rate max endurance • 1 From L = 2 ρV 2 S C L = WCos θ 2WCosθ V = • CLρS dh dt = -Vsin θ = - Cos θ ( 𝑀 𝐸 ) 2WCosθ 1 • CLρS AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Min. Sink Rate 𝐞( dh/dt) Cos θ ~ 1 = 0 𝐞𝐃 𝐌 dh dt = -Vsin θ = - Cos θ ( L C L 2WCosθ 1 D = ) L D CLρS C D dt = - ρS ( CD 3 2 ) dh 2W CL AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Sink Rate of Schweizer SGS 1-26 Glider http://www.5c1.net/Glider%20Performance%20Airspeeds.htm AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Gliding & Soaring Maintain Altitude in the air Without flapping wings or engine power Three methods of launching Winch launch Aerotow Motor Gliding AE-705 Introduction to Flight Lecture No. 13 Chapter-07
What can happen when engine fails? So what else can happen The aircraft can Certainly this is not glide… going to happen Lets see how AE-705 Introduction to Flight Lecture No. 13 Chapter-07
AIR CANADA 143 https://www.youtube.com/watch?v=oKbpR28l9xM AE-705 Introduction to Flight Lecture No. 13 Chapter-07
CLIMBING FLIGHT AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Climb position A320 Thrust levers https://www.google.com/search?q=thrust+levers+a320&source=lnms&tbm=isch&sa=X &ved=0ahUKEwjg6MXJ-MHUAhVCO48KHdX9D_8Q_AUIBigB&biw=1570&bih=748 AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Some Important Considerations Aerodynamics of climbing flight differs from gliding flight Thrust comes into consideration Climb differs for different a/c Depends on engine type http://amileofrunway.blogspot.in/2015/07/hang-gliding-over-new-zealands.html AE-705 Introduction to Flight Lecture No. 13 Chapter-07
ENGINE RATINGS MTT MCL MCR MCT max thrust that the maximum thrust thrust allowable maximum thrust engine can deliver that the engine for unlimited flight certified for en- for five minutes at can deliver with no duration at the route climb standard SL time limit design altitude atmosphere AE-705 Introduction to Flight Lecture No. 13 Chapter-07
EQUATIONS OF MOTION Forces involved in climb L T Climb angle φ horizontal D φ W AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Steady Climb (R/C) is the vertical component of the TAS • Affected by the climb angle • sin φ = (T – D) / W R/C = TAS · sin φ TAS R/C φ AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Drag vs. TAS DRAG THRUST (JET) D MIN TAS AE-705 Introduction to Flight Lecture No. 13 Chapter-07
http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node100.html AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Typical Climb Profile for Transport Jets CLIMB AT CONSTANT IAS/MACH The climb at a const. IAS until a certain MACH Climb is continued at const. MACH no Climb profile for an A320 is: 250kt / 300kt / M.78 Below FL100 Above FL100 until Until the end of (due to ATC) reaching M.78 climb (crossover altitude) AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Two parts of Climb First part of the climb (const. IAS), TAS as the aircraft climbs Second part of the climb (constant MACH), TAS as the aircraft climbs PA PA TROPOPAUSE 9% 30% Theoretical R/C Real R/C 25% TAS R/C AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Why Planes fly at a specific altitude? AE-705 Introduction to Flight Lecture No. 13 Chapter-07
CLIMB SPEEDS AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Climb Speeds CLIMB AT MAXIMUM ANGLE SPEED altitude to be reached over the shortest distance CLIMB AT MAXIMUM R/C SPEED altitude to be reached within the shortest time http://www.experimentalaircraft.info/flight- planning/aircraft-performance-3.php AE-705 Introduction to Flight Lecture No. 13 Chapter-07
V x v/s V y V x : Best Climb angle speed R/C V y : Best R/C speed TAS V x V y AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Climb Speeds CLIMB AT CONSTANT IAS As an aircraft climbs TAS Drag & R/C Results in a long and inefficient climb % Climb FL330 capability 50 FL290 60 FL250 70 FL200 80 90 100 IAS AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Power vs. TAS POWER power required Max diff. for jet max diff. for piston Min power req (jet) Min power req (piston) V xP V yP V xJ V yJ TAS AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Important Points V x = Best Angle of Climb Speed V y = Best Rate of Climb Speed V x < V y V x (jet) > V x (piston) V y (jet) > V y (piston) V x and V y change with altitude ! AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Optimum Climb Speed Optimum Climb Speed (OCS) In terms of efficiency and operative costs Usually higher than the best R/C speed (V y ) Factors affecting OCS: OCS ↑ when weight ↑ Fuel price ↑ OCS ↓ Maintenance and crew costs ↑ OCS ↑ Why ? Find out yourselves and upload on Moodle ! AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Climb Gradient Altitude gain per 100ft of horizontal distance Ratio of horizontal distance to vertical distance Climb gradient is affected by wind Climb gradient is improved with a headwind and reduced with a tailwind http://slideplayer.com/slide/1540042/ AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Factors Affecting Climb Climb gradient ↓ Pressure Altitude ↑ Rate of climb ↓ How does it happen ? Climb gradient ↓ Find out Temperature ↑ yourself..!! Rate of climb ↓ Report on Moodle Climb gradient ↓ Weight ↑ Rate of climb ↓ AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Step Climb Impractical to perform a continuous and slow climb during Cruise Why ?? Solution – Step Climb ATC !! AE-705 Introduction to Flight Lecture No. 13 Chapter-07
What is a Ceiling ? Ceiling is the altitude at which R/C has reached some minimum value Propulsion Absolute Service Design Combat Based on Based on Propulsive and structural R/C properties AE-705 Introduction to Flight Lecture No. 13 Chapter-07
What is a Ceiling ? Ceiling is the altitude at which R/C has reached some minimum value Propulsion Absolute Service Design Combat Based on Based on Propulsive and structural R/C properties AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Operative Ceiling ABSOLUTE CEILING The aircraft cannot climb above the absolute ceiling It is determined by the aerodynamic & propulsive properties of the aircraft R/C = 0 http://www.boldmethod.com/learn-to-fly/performance/vx-vy-altitude-and-where-they-meet/ AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Other Ceilings PROPULSION CEILING The altitude that the available thrust provided by the engines permits to reach It is usually lower than the absolute ceiling SERVICE CEILING At this altitude the aircraft has a maximum ROC of 100 fpm DESIGN CEILING Maximum altitude that the aircraft can reach due to structural limits We will see this later on in V-n diagram AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Ceilings based on max R/C Absolute ceiling: R/C MAX = 0 fpm Service ceiling: R/C MAX = 100 fpm Cruise ceiling: R/C MAX = 300 fpm Combat ceiling: R/C MAX = 500 fpm Combat ceilings are basically meant for highly maneuverable a/c Eg – MiG 29, F-16 http://joeclarksblog.com/?p=2929 AE-705 Introduction to Flight Lecture No. 13 Chapter-07
Next Class on Wednesday 4 th October SUSTAINED LEVEL TURN + PULL UP AE-705 Introduction to Flight Lecture No. 13 Chapter-07
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