ARAPA: AIrcraft Selection, Airfoil research and Lift
Your task in this and the following modules’ project activities is to systematically investigate and document the performance characteristics of a specific propeller-driven general aviation (GA) aircraft. As a team, please select a single-engine, monoplane aircraft (i.e., no twin-engine, no bi-plane, no jet).
To provide some ideas, consider the following example aircraft:
- Cessna (150, 152, 162, 172, or 182)
- Piper (Cub, SuperCub, Comanche, or Cherokee)
- Cirrus (SR20 or SR22)
- Beechcraft (Bonanza or T-6)
- Mooney (M20)
- Pilatus (PC-6, PC-7, PC-9, PC-12, or PC-21)
- Diamond (DA-20, DA-40, or HK-36)
- Vans (any RV)
Note: Engineering, unmanned systems, and mixed student groups are permitted to investigate a model-sized version of a single-engine monoplane if proposed to and approved by their instructor.
Once you selected your team’s project aircraft, please review the “2.3.1 – ARAPA: Resources and Inputs” page.
For this assignment, your task will be to collaboratively create an instructional team wiki (Canvas page within your group work space – see again ARAPA Overview Page for instructions) that explains how to find key airfoil aspects and related attributes of lift production for your selected aircraft. All provided answers must exemplify the concepts with specific numbers/values for your aircraft (for example, we are not looking for the stall speed as given in the POH or on Wikipedia but want to see how you derived at a calculated stall speed based on your airfoil data, the particulars of your selected aircraft, and the application of the lift equation). Therefore, you will need to research some additional information and/or use your formula knowledge from this week’s readings to derive all the variables necessary to solve the lift equation.
As a starting point and the minimum content to cover, a short list of considerations and discussion points is provided below and can be directly copied into your team’s wiki to be completed in the process.
- Main airfoil for your selected aircraft
- Stall AOA and associated CLmax
- Zero-lift AOA
- Comparison of your main airfoil to a symmetric airfoil
- Resultant attribute discussions for your selected aircraft
- Calculated stall speed
- How does lift change with airspeed if a constant AOA and altitude are held? (provide specific examples)
- How does lift change with altitude if a constant AOA and airspeed are held? (provide specific examples)
- How do the required CL and AOA for your specific aircraft (at a specific weight) change with changes in airspeed? (provide specific examples)
- What happens if the required CL is larger than CLmax of your airfoil, and what speed regime is usually associated with that condition?
The key to answering some of the questions is to provide specific calculation examples for your aircraft that showcase the points made. There are various forms in which you could do so, including self-generated tables and graphs or comparisons of key cases (e.g., comparing a low, medium, and high altitude case). You will notice that all such calculations are ultimately based on repeated but different applications of the lift equation. Therefore, in order to apply the lift equation, a couple of aspects about your aircraft have to be known (i.e., researched) or assumed (i.e., detailed in your explanations). These parameters include:
- Wing configuration (may include wing span, wing area, aspect ratio, average chord, etc. – keep in mind that the lift equation ultimately requires wing area to calculate with.)
- The weight of the aircraft (probably somewhat assumed but should definitely fall between the empty and max weight of the aircraft)