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Senior Design > Lab 1 (Loftin) and Intro > Flashcards

Lab 1 (Loftin) and Intro Flashcards

1
Q

What are the three main flight vehicle classifications?

A

Aircraft
Space Access Vehicle
Spacecraft

Lecture 0–Slide 3

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2
Q

What are the three main ways that fixed wing aircraft are categorized with respect to function?

A

Civil
Military
Research

Lecture 0–Slide 4

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3
Q

What are the typical organizational schemes of senior capstone projects for aerospace engineering?

A
  1. Design-Build-Fly
  2. Individual/Team Project
  3. AIAA Design Competition
  4. Industry Sponsored/Monitored Project

Lect 1 – Slide 4

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4
Q

Form follows ______.

A

Function.

Lect 1 – Slide 6

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5
Q

What was the central argument of the Sears-Foa debate?

A

The range of the flying wing and more generally the applicability for military bomber applications.

Lect 1 – Slide 8

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6
Q

The “struggle to harmonize the balance between design proficiency available vs. design proficiency required over a 70-year period” was mentioned with respect to what case study?

A

The Sears-Foa debate over the range of a flying wing.

Lect 1 – Slide 8

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7
Q

Who are William R. Sears and Irving L. Ashkenas?

A

Two engineers for Northrop that worked to develop YB-35 flying wing bomber.

Lect 1 – Slide 8

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8
Q

What was Foa’s concern with respect to the flying wing analysis presented by Ashkenas and Sears?

A

The maximum range proclaimed by Spears and Ashkenas was actually a minimum.

Lect 1–slide 9

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9
Q

What are the four isolated generations of flying wings?

Hint: What companies spearheaded the first four phases of flying wing aircraft design?

A
  1. Horten
  2. Northrop 1
  3. Northrop 2
  4. Airbus/Boeing

Lecture 1 – Slide 15

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10
Q

What are three unique emphasis points of the aerospace capstone?

A
  1. Solution Space Screening
  2. Solution Space Visualization
  3. Multi-Diciplinary risk assessment

Lecture 1 – Slide 16

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11
Q

What are the
“ladder steps” in the capstone learning objectives (from bottom to top)? Which is the most important?

A
  1. Analyze
  2. Integrate
  3. Iterate
  4. Converge (most important)
  5. Screen
  6. Visualize
  7. Assess Risk

Lecture 1 – Slide 17

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12
Q

In terms of the design ladder, undergraduate education primarily focuses on which step?

A

Step 1–Analyze.

Lecture 1–Slide 17

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13
Q

Who founded skunkworks?

A

Kelly Johnson

Lecture 1 – Slide 18

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14
Q

What are the two main classifications of subsonic/transonic commercial airplanes?

A
  1. Prop
  2. Jet

Lecture 1 – Slide 39

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15
Q

What are the two main categories of supersonic commercial aircraft?

A

Supersonic Buisness Jet (SBJ)
Suspersonic commercial transport (SCT)–First Gen, and 2nd gen

Lecture 1 – Slide 50

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16
Q

Give some examples of 1st generation Supsonic commercial transports (SCTs).

A
  1. Concorde
  2. Tupelev Tu-144
  3. Boeing B2707
  4. Douglas AST

Lecture 1– Slide 50

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17
Q

Why does Loftin’s method not require iteration?

A

Due to the way the empty weight formulation is calculated.

Hypersonic Convergence – Slide 3

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18
Q

In Loftin’s approach, empty weight is correlated with __________ instead of _______.

A

Power Loading
TOGW

Hypersonic Convergence – Slide 3

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19
Q

List all six steps for the Roskam design process.

A
  1. Guess TOGW
  2. Determine We from regression
  3. Determine Wf from the trajectory
  4. Calculate Performance constraints
  5. Determine S and T from TOGW_new
  6. Iterate until TOGW is converged

Hypersonic Convergence – Slide 4

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20
Q

Conventional sizing methods for subsonic/supersonic aircraft only _______, leaving the _____ and ____to be sized independently.

A

wing and propulsion system simultaneously

fuselage and empennage

Hypersonic Convergence – Slide 8

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21
Q

To size a hypersonic vehicle, the sizing methodology must _____________.

A

Consider the total integration of the system simultaneously. In other words, all aspects of the design must be considered simultaneously.

Hypersonic Convergence – Slide 8

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22
Q

Explain how hypersonic convergence considers the total integration of the system simultaneously.

A

By explicitly including volume in the convergence logic and defines both the weight and the volume associated with all critical components.

Hypersonic Convergence – Slide 8

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23
Q

For a hypersonic vehicle to be capable of useful missions a single blended body must generate/include what main four items?

A
  1. Volume
  2. Lift
  3. Thrust
  4. Control Forces

Hypersonic Convergence – Slide 9

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24
Q

Hypersonic convergence relies on solving how many core equations iteratively?

A

Two equations. The volume budget and the weight budget.

Hypersonic Convergence – Slide 11

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25
Q

In the hypersonic convergence equations, which parameter is integrated until the weight and volume budged equations coverage?

A

The planform area.

Hypersonic Convergence – Slide 11

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26
Q

What is Kuchemanns slenderness parameter?

A

A nondimensional parameter which relates the volume of the vehicle to its planform area.

Hypersonic Convergence – Slide 12

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27
Q

What is the definition (mathmatically) of Kuchemann’s slenderness parameter (tau)?

A

tau = V_tot / S_pln^(3/2)

Hypersonic Convergence – Slide 12

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28
Q

What are the three required initial values for hypersonic convergence?

A
  1. Range of Tau
  2. TOGW
  3. Planform area (S_pln)

Hypersonic Convergence – Slide 14

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29
Q

What does the term K_W refer to in hypersonic convergence methodologies?

A

The ratio of the wetted planform area to the total platform area.

Kw:= S_wet/S_pln

Hypersonic Convergence – Slide 18

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30
Q

What is the analog for Loftin’s performance matching in hypersonic convergence?

A

Constraint analysis

Hypersonic Convergence – Slide 23

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31
Q

And hypersonic convergence what are the primary outputs of constraint analysis?

A

The thrust to weight ratio (T/W).

Hypersonic Convergence – Slide 23

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32
Q

In hypersonic convergence what is the objective of the trajectory analysis?

A

Compute the fuel fraction required to perform the specified mission.

Hypersonic Convergence – Slide 27

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33
Q

In hypersonic convergence trajectory analysis, what is the definition of the fuel fraction?

A

Weight of the fuel divided by the takeoff gross weight.

ff = W_fuel / TOGW

Hypersonic Convergence – Slide 27

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34
Q

What is the “heart” of the hypersonic convergence process?

A

The wight and volume budget.

Hypersonic Convergence – Slide 29

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35
Q

Fundamentally, the hypersonic convergence process can be through of as _____________.

A

The solution of two algebraic equations. The two equations are the weight budget and the volume budget equations.

Hypersonic Convergence – Slide 29

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36
Q

In the hypersonic convergence logic, when is convergence attained?

A

When the initial takeoff gross weight and the new takeoff gross weight are approximately the same.

Hypersonic Convergence – Slide 37

37
Q

From what period what the “time of little change” according to Loftin?

A

1918–1926

Lab Mod 1 – Slide 12

38
Q

During the period between 1918–1926, general aviation in the US consisted of?

A

Barnstormers mostly utilizing surplus Curtiss JN-4D Jenny’s.

Lab Mod 1 – Slide 12

39
Q

During the period between 1918–1926, why was wing loading kept low?

A

To operate out of existing airfields with short runways. Low wing loading corresponds to low stall speeds. This allows pilots to use shorter runways.

Lab Mod 1 – Slide 12

40
Q

What was the first airplane to utilize a wing with greater than 6 to 8 percent thickness ratio?

A

The Fokker Trimotor

Lab Mod 1 – Slide 14

41
Q

During the period between 1918 and 1926, what was the primary driver of airplane development?

A

Air races with high speed aircraft.

Lab Mod 1 – Slide 14

42
Q

From the Loftin study, what period was the “Time of revolution?”

A

1926 to 1939

Lab Mod 1 – Slide 16

43
Q

During the period between 1926 to 1939, what plane popularized the monoplane configuration?

A

The Ryan NYP

Lab Mod 1 – Slide 17

44
Q

What was the first aircraft in the US to employ a smooth all-metal stressed skin semi-monocoque type structure?

A

The Northrop Alpha

Lab Mod 1 – Slide 19

45
Q

What was the first aircraft that allowed airline companies to make a profit off passenger transport and not just the mail?

A

The DC-3.

Lab Mod 1 – Slide 20

46
Q

Why is the Loftin approach still valid today?

A

Because the evolution of prop-driven aircraft has mostly stagnated since the advent of jet aircraft.

Lab Mod 1 – Slide 2

47
Q

What was the education, employment, and position of Lawrence K. Loftin?

A
  1. University of Virginia
  2. NASA Langley
  3. Director of Aeronautical research

Lab Mod 1 – Slide 2

48
Q

According to Loftin, the evolution of the modern aircraft can be characterized by _______________.

A

A series of technological levels which extend over a period of years.

Lab Mod 1 – Slide 2

49
Q

According to Loftin, why was there little a/c development between 1918-1926?

A

The prevailing attitude after WWI was that there would not be another major armed conflict. Aircraft research suffered as a consequence.

Lab Mod 1 – Slide 12

50
Q

What aircraft did Charles Lindbergh fly from New York to Paris?

A

A Ryan NYP

Lab Mod 1 – Slide 16

51
Q

What was the Lockheed Vega’s claim to fame?

A

It had the highest level of aerodynamic efficiency achieved by a high-wing monoplane with fixed landing gear by 1930.

Lab Mod 1 – Slide 17

52
Q

Why was the Lockheed Orion only produced in limited quantities?

A

The Orion was a single-engine aircraft. In the late 1930s, government regulations disallowed the use of single-engine aircraft for scheduled passenger-carrying operations.

Lab Mod 1 – Slide 19

53
Q

The B-17 bomber incorporated the technological advances of the DC-3 and the Boeing 247D but varied in what respect?

A

The B-17 has four engines instead of two.

Lab Mod 1 – Slide 22

54
Q

The first aircraft which assembled most of the advanced design characteristics of the 1930s was the _________.

A

Boeing D47

Lab Mod 1 – Slide 19

55
Q

What were some of the “synergistic” design features of the Boeing 247?

A
  1. Cantilever wings
  2. Retractable landing gear
  3. Radial engines
  4. Variable speed, constant speed props
  5. Single-speed geared turbocharger
  6. All metal stressed skin structure
  7. IFR instrumentation

Lab Mod 1 – Slide 20

56
Q

Why did the Boeing 247 have a low wing loading?

A

Because it did not have any high-lift devices.

Lab Mod 1 – Slide 20

57
Q

True or False
The DC-3 incorporated all the advanced technical features of the Boeing 247 and the Douglas DC-2.

A

True

Lab Mod 1 – Slide 20

58
Q

How many passengers could the DC-3 carry?

A

21

Lab Mod 1 – Slide 20

59
Q

Why does the DC-3 have a higher zero-lift drag coefficient than the Boeing 247?

A

The DC-3 has a larger fuselage. It therefore has a larger ratio of wetted area to wing area.

Lab Mod 1 – Slide 21

60
Q

How do the lift-to-drag ratio values compare between the DC-3 and the Boeing 247?

A

The L/D value for the DC-3 is slightly higher than the Boeing 247 (14.7 vs. 13.5). The higher aspect ratio of the DC-3 accounts for the discrepancy.

Lab Mod 1 – Slide 21

61
Q

What are the three aircraft associated with the so-called “final configuration” of prop-driven aircraft?

A
  1. The Douglas DC-3
  2. The Boeing B-17
  3. The Seversky XP-35

Lab Mod 1 – Slide 22

62
Q

What post-1930 aircraft is generally associated with a low purchase price, operation, and maintenance cost while being easy to fly.

A

The Piper Cub

Lab Mod 1 – Slide 23

63
Q

What airplane represents the stagnation point for Bi-Plane Design?

A

The Beech Staggerwing D-17

Lab Mod 1 – Slide 24

64
Q

What is the distinctive feature of the Beech Staggerwing D-17?

A

The negative stagger of the wings. The top wing is further aft than the bottom.

Notes: The top wing was set back to accommodate stability requirements.

Lab Mod 1 – Slide 24

65
Q

What was the main difference between aeronautical research in WWI vs. WWII?

A

WWI was characterized by experimentation of all types. By WWII, the final form of the prop-driven aircraft had crystallized. The emphasis was now placed on achieving higher performance with the standard design.

Lab Mod 1 – Slide 26 & 27

66
Q

In order to accommodate the aircraft needs of the second world war, what was aeronautical research primarily focused on?

A
  1. Lighter weight
  2. stronger structures
  3. More powerful engines
  4. Detailed aerodynamic refinement

Lab Mod 1 – Slide 27

67
Q

True or False
According to Loftin, “the use of NACA laminar flow airfoil sections has never resulted in any significant reduction in the drag as a result of the achievement of laminar flow.”

A

True

Lab Mod 1 – Slide 28

68
Q

To accomodate high wing loading while maintaining low stall speeds, aerodynamic research center on _______.

A

High lift devices.

Lab Mod 1 – Slide 28

69
Q

True or False
The leading edge flap was a German development and data was only made available after the war.

A

True

Lab Mod 1 – Slide 28

70
Q

What are some reasons why the “ideal” zero-lift drag coefficient is not attainable in practice?

A
  1. Projections of outside items
  2. Roughness/unevenness of the surface
  3. Leakage of air through the structure
  4. Utilization of air for cooling purposes

Lab Mod 1 – Slide 29

71
Q

True or False
During the development period of WWII, it was often the case that reductions in drag were more a function of good design rather than a different configuration.

A

True

Lab Mod 1 – Slide 29

72
Q

What ultimately limits the use of propeller aircraft?

A

The compressibility limits when approaching and reaching the critical Mach number.

Lab Mod 1 – Slide 30

73
Q

How do aircraft compressibility problems typically manifest themselves on airplanes?

A
  1. Limited speed
  2. Large changes in stability and trim characteristics
  3. Loss of control effectiveness
  4. Loss of propulsive efficiency
  5. Aircraft oscillation and general lack of control

Lab Mod 1 – Slide 30

74
Q

What “flying qualities” did the 1941 NACA report suggest?

A
  1. Longitudional Stability/Control
  2. Lateral Stability/Control
  3. Stalling Characteristiics

Lab Mod 1 – Slide 32

75
Q

What aircraft is commonly associated with the highest level of technical refinement ever achieved in a prop-driven fighter aircraft?

A

The P-51 mustang.

Lab Mod 1 – Slide 33

76
Q

Who is credited for the design of the P-51 mustang?

A

Edgar Schmued

Lecture Notes

77
Q

What WWII era aircraft had a speed higher than the P-51 Mustang?

A

The Dornier Do 335 Pfiel (tractor and push props)

Lab Mod 1 – Slide 36

78
Q

True or False
New propeller-driven aircraft manufactured since 1945 have largely exceeded the capabilities of WWII-era craft.

A

False. New propeller-driven aircraft designed since WWII are of the same general layout, and their aerodynamic qualities have not greatly improved.

Lab Mod 1 – Slide 39

79
Q

What is likely the most significant improvement to prop aircraft since WWII?

A

The supercharger for reciprocating engines and pressurized cabins.

Lab Mod 1 – Slide 39

80
Q

What two aircraft hold the seaplane and land-based prop-driven speed records, respectively?

A

Seaplane = Macchi M.C.72
Land Based = F8F Bearcat Rare Bear

Lab Mod 1 – Slide 39

81
Q

What two families of aircraft dominated passenger transport until jet transport became available?

A

The DC-6 and DC-7 and the Lockheed Constellation series.

Lab Mod 1 – Slide 40

82
Q

The Lockheed L.1049G Super Constellation was known for what qualities?

A
  1. About 15% of total engine power was attributed to recycled exhaust velocity.
  2. “Probably” the lowest specific fuel consumption of any reciprocating aircraft engine.

Lab Mod 1 – Slide 41

83
Q

What are the pros and cons of a turbo-prop vs regular reciprocating engine?

A

Per unit weight, the turboprop offers 2 to 3 times the shaft horsepower provided by a reciprocating engine but has a significantly higher specific fuel consumption.

Lab Mod 1 – Slide 41

84
Q

What was the largest passenger-carrying turboprop aircraft to date?

A

The Tupolev Tu-114

Lab Mod 1 – Slide 42

85
Q

In terms of executive aircraft, what aircraft is considered one of the most exceptional aircraft?

A

Piaggio P180 Avanti

Lab Mod 1 – Slide 43

86
Q

The Piaggio P180 Avanti is known for what characteristics?

A

The Three surface configuration (TSC). This reduces the drag at any c.g. location.

Lab Mod 1 – Slide 43

87
Q

What are the key performance parameters provided by Loftin?

Hint: There are 8

A
  1. Maximum Speed
  2. Stall Speed
  3. Wing Loading
  4. Maximum Lift coefficient
  5. Power Loading
  6. Zero lift drag coefficient
  7. Skin friction coefficient
  8. Maximum L/D

Lab Mod 1 – Slide 47

88
Q

What are the three phases of aircraft design development?

A
  1. Conceptual Design
  2. Preliminary Design
  3. Detailed Design

Lab 2 – Slide 4

Senior Design (13 decks)

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