Lab 2: Parametric Sizing Process Flashcards
What are the general phases of aircraft development (design)?
- Conceptual Design
- Preliminary Design
- Detail Design
Lab 2 – Slide 4
Give a general definition of “conceptual design.”
Development and evaluation of design alternatives.
Lab 2 – Slide 4
Give a general definition of “preliminary design.”
Development of a baseline specification for manufacturing.
Lab 2 – Slide 4
Give a general definition of “detail design.”
Development, testing, certification.
Lab 2 – Slide 4
The conceptual design process consists of what three distinct steps?
- Parametric Sizing
- Configuration Layout
- Configuration Evaluation
Lab 2 – Slide 4
Parametric sizing gives ___________.
The definition of the gross vehicle design solution space.
Lab 2 – Slide 5
Describe the configuration Layout stage.
Brainstorming and initial sizing of possible configuration concepts.
Lab 2 – Slide 5
Describe the configuration evaluation phase.
Evaluation of initial configuration concepts and trade studies.
Lab 2 – Slide 5
What tools are available to complete the parametric sizing step.
- Standard Design Ladder
- Breguet Range
- Hypersonic Convergence
- Loftin Sizing
- Roskam I sizing
Lab 2 – Slide 6
Out of parametric sizing, configuration layout, and configuration evaluation, which is the “weak link” in conceptual design.
Parametric sizing.
Lab 2 – Slide 6
What tools are available for the completion of the configuration layout step?
- Brainstorming
- Database statistics
- Knowledge Expertise
- Design guidelines/rules
- AI
Lab 2 – Slide 7
Why are design related software applications avoided during parametric sizing?
Because they tend to obscure the design process in a “black box.”
Lab 2 – Slide 10
What variables are plotted on the Loftin convergence chart?
- Climb Criterion
- Take-off field length
- Max Speed
- Stall speed and landing field length
Lab 2 – Slide 10
The match point on the convergence chart is characterized by:
- Size Required
- Resulting weight
- Power required
Lab 2 – Slide 11
What are the design ladder steps? What is the most important item?
- Analyze
- Integrate
- Iterate
- Converge (most important)
- Screen
- Visualize
- Assess Risk
Lab 2 – Slide 11
Modern prop-driven aircraft are usually designed to meet what two performance objectives? What do these objectives entail?
Airport Performance
>Stall Speed
>Ldg/Takeoff length
>Climb perf
Cruise Performance
>Max cruise speed
>range
>payload
Lab 2 – Slide 12
In terms of performance characteristics, the size required is a function of ____ and _______.
wing area
wing loading
Lab 2 – Slide 12
In terms of performance characteristics, the resulting weight is a function of _______ and _______.
empty weight
fuel weight
Lab 2 – Slide 12
In terms of performance characteristics, the power required is a function of _______ and _______.
power
power loading
Lab 2 – Slide 12
What FAR is associated with the certification of GA?
Part 23
Lab 2 – Slide 13
What FAR is associated with the certification of transport aircraft?
Part 25
Lab 2 – Slide 13
True or False
The propulsive efficiency is the product of the prop efficiency and the installation efficiency.
True
Lab 2 – Slide 29
What is the benefit of calculating the power index?
It serves as a constant of proportionality between the total drag coefficient and various aerodynamic and aircraft parameters.
Lab 2 – Slide 34
CL_max depends on what design parameters?
- Airfoil Section
- Flap system
- Wing platform shape
- Wing surface roughness
- Reynolds Number
Lab 2 – Slide 37
True or False
The stall speed of an airplane is independent of wing loading.
False. See Eq. 3.14 on slide 37.
Lab 2 – Slide 37
