Modeling of the Blackbird Wind-Powered Ground Vehicle
Bibliographic record
Abstract
View Video Presentation: https://doi.org/10.2514/6.2023-0910.vid The Blackbird vehicle is a wind-powered ground vehicle purported to be capable of propelling itself directly downwind faster than the wind. This capability, demonstrated in 2010, has proven to be controversial because it is difficult to understand how a vehicle travelling faster than the surrounding air can collect energy from that air. This paper presents a mathematical model and corresponding simulation of the Blackbird vehicle. Our simulation results demonstrate that this vehicle should, indeed, be capable of travelling directly downwind much faster than the ambient wind speed. The simulation results show good correspondence with the few available experimental results. The simulation is also used to provide pointers to further improve the vehicle's performance. It is found that using variable gearing could improve the vehicle's acceleration, though would not significantly improve its terminal velocity. A sensitivity analysis is performed on the losses (rolling resistance, air drag and transmission efficiency) and it is found that improvement in the transmission efficiency would lead to the greatest increase in terminal velocity.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
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".