Wind Tunnel Test Results for a 0.2 Scale 4-Bladed Tiltrotor Aeroelastic Model
Bibliographic record
Abstract
A 0.2 scale 4-bladed stiff inplane tiltrotor aeroelastic model was tested at the NASA Langley Transonic Dynamics Tunnel (TDT) in October and November 2011. This aeroelastic model included a novel stepover control mechanism designed to improve whirl flutter stability boundaries for a 4-bladed tiltrotor. The stepover control mechanism provides the rotor kinematic control coupling necessary for stability but is designed to fit within the limited space of a 4-bladed rotor hub. Airplane mode stability boundaries with and without the stepover control mechanism installed were measured during the wind tunnel test. Stability test results show that the stepover mechanism provides as much or more stability to the 4-bladed rotor as the conventional control system provided for the 3-bladed rotor. With the stepover control mechanism removed (i.e. reverting to a conventional control system design), the 4-bladed configuration was found to be unstable at significantly lower airspeeds. In addition, a GPC (Generalized Predictive Controller) active stability control algorithm was tested and shown to significantly increase the subcritical damping of the 4-bladed aeroelastic model with a conventional control system installed. Rotor loads and vibrations were measured at various nacelle angles and trim conditions. For direct comparison with the 4-bladed rotor, rotor loads were also measured on a 0.2 scale 3-bladed V-22 rotor. Differences in the dynamic behavior and loads of the two rotor configurations are explored.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".