Turboshaft engine performance comparison between CVT and fixed ratio transmission for a variable speed rotor helicopter
Bibliographic record
Abstract
In a usual turboshaft engine for helicopter applications, the free power turbine (FPT) rotational speed is normally governed ensuring that the rotor speed is as constant as possible for each type of flight maneuver. The main reason for choosing a constant rotational speed is linked to the supposed decrease in engine efficiency at part load (typical variations in speed do not exceed 15% [1]), as well as because variable speed drives trains of resonant frequencies into the airframe [2]. However, recent studies [3],[4] and real implementations bringing up composites into the airframe structure make it possible to successfully accommodate varying speed rotors without hitting resonant frequencies and with even better engine performance [3]. A recent example is the variable speed Pratt & Whitney Canada PW207D turboshaft, a single-stage shrouded power turbine which powers Boeing's A160 Hummingbird and Bell Helicopter's Eagle Eye UAV.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".