Aerodynamics and ice tolerance of the large passenger aircraft advanced rear end forward swept horizontal tailplane with leading edge extension
Why this work is in the frame
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Bibliographic record
Abstract
• Large passenger aircraft empennage three-dimensional inflight icing simulation. • Three-dimensional CFD of large passenger aircraft empennages with ice. • Iced forward swept horizontal tail aerodynamics and lifting performance. • Effect of forward sweep on iced forward swept horizontal tail lift. • Effect of leading edge extension geometry on iced forward swept horizontal tail lift. The advanced rear end (ARE) forward swept horizontal tail (FSHT) has been proposed to allow a more compact empennage to reduce weight, drag, and, thus, fuel burn. Large passenger aircraft (LPA) empennages are typically sized up to satisfy performance and handling requirements under critical icing conditions. One such requirement is sufficient low speed (negative) lifting performance for the roundout manouevre following 45 minutes of flight in a holding pattern in icing conditions. The FSHT geometry has the possibility to include a leading edge extension (LEX) in the droplet shadow zone of the fuselage contraction where it could have some protection from icing and, thus, reduce tail size. This paper addresses the topics of the use of three-dimensional inflight icing simulation and CFD of iced tails in the industrial environment, inflight icing of the FSHT with LEX, and lifting performance and aerodynamics of the iced FSHT with LEX. The practice and feasibility of using three-dimensional multishot icing simulation in the LPA design environment are described and demonstrated. First, full aircraft air flow and droplet calculations were carried out using the finite element method with solution error-based anisotropic mesh adaptation, on a single geometry, to calculate inlet and outlet condition profiles for an empennage-only icing simulation domain. Full aircraft-representative, three-dimensional, multishot icing simulations were then carried out to calculate 45 minutes of ice accretion in a holding pattern in Appendix C glaze icing conditions for eight different geometries. Three dimensional CFD with the k-ω SST turbulence model was then used to calculate lifting performance and aerodynamics of each, with and without ice, in a roundout flight condition from 0° to -15° AoA. Analysis is presented for three variations in FSHT forward sweep with a fixed gothic LEX geometry, three variations in LEX chord with a 10°FSHT geometry, and three variations in LEX span with a 10°FSHT geometry. Iced lifting performance is found to correlate positively with forward sweep and LEX chord and have a more minor positive correlation with LEX span. In addition to the expected LEX vortex, a tip leading edge vortex is identified as a key ice tolerant FSHT lifting flow mechanism. Detailed flow field analysis provides insight into the complex interplay between the two flow mechanisms and the implications for iced lifting performance.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it