Rotary Wing Platforms Research Articles

Nature-inspired in-flight foldable rotorcraft

The paper presents a novel rotary wing platform, that is capable of folding and expanding its wings during flight. Our source of inspiration came from birds’ ability to fold their wings to navigate through small spaces and dive. The design of the rotorcraft is based on the monocopter platform, which is inspired by the flight of Samara seeds. The wings are constructed by applying origami techniques to fold them in flight. Two configurations are presented, featuring active or passive mechanisms for wing-folding depending on specific application requirements. The two configurations can reduce their overall footprint by approximately 39% and 69% while in flight. A cyclic controller is implemented for controlling the translational motion, where the direction is controlled by pulsing the motors at a specific instance during each cycle of rotation. We have presented experimental results to prove the control of our platform in different modes while in flight. The presented platforms enhance the practical uses of the monocopter platform by providing it with the ability to reduce its footprint while in flight actively, or by allowing them to dive through the air without any additional actuator.

Acoustic Impact of Hybrid-Electric DEP Aircraft Configuration at Airport Level

The Italian research project PROSIB (PROpulsione e Sistemi IBridi per velivoli ad ala fissa e rotante), is a 30-month initiative funded by the Italian Ministry of University and Scientific Research (MIUR) and coordinated by the Leonardo company. The project is aimed to investigate configurations for regional aircraft and rotary wing platforms and architectures for propulsion systems, and is dedicated to the identification of the best strategy for their use, given different on-board energy sources. The reduced environmental impact is the key for the success of the new hybrid/electric aircraft configurations. This not only considers the chemical pollution introduced in the atmosphere, but also the noise produced on the surrounding area of airports. The present paper describes the acoustic impact assessment resulting from the inclusion of new propulsion technologies and new configurations of regional aircraft (ATR42 pax) in a reference airport area.

NSOF AND ROTARY-WING PLATFORMS – INTEGRATED OR JOINT?

Abstract: There is today a burgeoning discussion about how Romanian Naval Special Operations Forces (RNSOF) is supported in maritime operations by the conventional means of the Romanian Navy rotary-wing platforms. As part of this approach, we set out to analyze the regulatory framework for ensuring the support of naval aviation in the execution of NSOF missions. Thus, we will study the evolution of the cooperation of the ROU Navy Helicopter Group and NSOF from the perspective of regulations on cooperation, training, common standard operating procedures, references on standardization and safety in the execution of training and missions in the maritime environment. This research addresses an aspect of special operations that has yet to be explained adequately. To achieve this goal, we will describe how these operations are conducted in NATO countries, which have integrated maritime aviation in support of naval forces for special operations in the maritime environment. According to the specified causes to achieve our objectives, we will search for solutions to compensate or reduce the gap between necessity and reality. Through comparative analysis and documentation on the strategies used by foreign military forces, with similar roles and missions, we will provide solutions that will cover an area that can vary from adapting procedures to establishing the need to develop certain regulations. Our study is addressed to persons involved or interested in the military field and special naval operations and aims to highlight the importance of developing the NSOF capacity to cooperate with integrated maritime aviation and adjusted to the requirements of the execution of special maritime operations. Taking these recommendations into account will increase the effectiveness of NSOF maritime operations with the support of rotary-wing platforms while ensuring the transition to a robust/ real joint NSOF capability in response to existing threats in the Black Sea.

Investigation of the influence of optical turbulence on DIRCM laser’s jamming effectiveness: A wave-optics approach

Due to their exceptionally large jam-to-signal ratios (J/S), Directed Infrared Countermeasure (DIRCM) systems are the most efficient means for defeating heat seeking missiles. Although many studies have investigated DIRCM systems, the influence of optical turbulence on the jamming code effectiveness is mostly ignored. However, due to optical turbulence caused by the exhaust plume of the air platform and the atmosphere, a DIRCM laser’s beam may be exposed to time-varying intensity fluctuations, which may dramatically reduce the effective J/S at the seeker’s aperture compared to the one at the platform. In addition, previous studies have generally focused on the signal processing stages of seeker heads while ignoring diffractive and aberrative properties of the missile optics. In this study, we employ a wave-optics approach for estimating the jamming code effectiveness under turbulence. Specifically, we investigate time-varying influence of several degrees of optical turbulence on DIRCM laser beams with specified beam quality factors (M2) that are modulated with various jamming patterns. In our model, the DIRCM laser beam first passes through a highly turbulent region, which is caused by the rotor downwash of the exhaust plume of a rotary-wing platform. Next, the DIRCM laser beam propagates in an atmospheric turbulence region for much longer distances (on the order of few km’s) until it reaches the missile. Laser beam propagation in both turbulence regimes is simulated using the split-step method. Subsequently, using the ZEMAX software and its wave-optics-based Physical Optics Propagation (POP) package, we employ a generic model for the optical system of a first-generation spin-scan seeker and obtain the time-dependent intensity profiles of the laser beam at the focal point. Generic models for an uncooled lead-sulfide detector and the following signal processing stages have also been included in the model.

Trajectory optimization under kinematical constraints for moving target search

Various recent events in the Mediterranean sea have shown the enormous importance of maritime search-and-rescue missions. By reducing the time to find floating victims, the number of casualties can be reduced. A major improvement can be achieved by employing unmanned aerial systems for autonomous search missions. In this context, the need for efficient search trajectory planning methods arises. Existing approaches either consider K-step-lookahead optimization without accounting for kinematics of fixed-wing platforms or propose a suboptimal myopic method. A few approaches consider both aspects, however only applicable to stationary target search. The contribution of this article consists of a novel method for Markovian target search-trajectory optimization. This is a unified method for fixed-wing and rotary-wing platforms, taking kinematical constraints into account. It can be classified as K-step-lookahead planning method, which allows for anticipation to the estimated future position and motion of the target. The method consists of a mixed integer linear program that optimizes the cumulative probability of detection. We show the applicability and effectiveness in computational experiments for three types of moving targets: diffusing, conditionally deterministic, and Markovian. This approach is the first K-step-lookahead method for Markovian target search under kinematical constraints.

Field and en route resuscitative endovascular occlusion of the aorta: A feasible military reality?

Severe noncompressible torso hemorrhage remains a leading cause of potentially preventable death in modern military conflicts. Resuscitative endovascular occlusion of the aorta (REBOA) has demonstrated potential as an effective adjunct to the treatment of noncompressible torso hemorrhage in the civilian early hospital and even prehospital settings-but the application of this technology for military prehospital use has not been well described. We aimed to assess the feasibility of both field and en route prehospital REBOA in the military exercise setting, simulating a modern armed conflict. Two adult male Sus Scrofa underwent simulated junctional combat injury in the context of a planned military training exercise. Both underwent zone I REBOA in conjunction with standard tactical combat casualty care interventions-one during point of injury care and the other during en route flight care. Animals were sequentially evacuated to two separate forward surgical teams by rotary wing platform where the balloon position was confirmed by chest x-ray. Animals then underwent different damage control thoracic and abdominal procedures before euthanasia. The first swine underwent immediate successful REBOA at the point of injury 7 minutes and 30 seconds after the injury. It required 6 minutes total from initiation of procedure to effective aortic occlusion. Total occlusion time was 60 minutes. In the second animal, the REBOA placement procedure was initiated immediately after take off (17 minutes and 40 seconds after the injury). Although the movements and vibration of flight were not significant impediments, we only succeeded to put a 6-French (Fr) sheath into a femoral artery during the 14 minutes flight due to lighting and visualization challenges. After the sheath had been upsized in the forward surgical team, the REBOA catheter was primarily placed in zone I followed by its replacement to zone III. Both animals survived to study completion and the termination of training. No complications were observed in either animal. Our study demonstrates the potential feasibility of REBOA for use during tactical field and en route (flight) care of combat casualties. Further study is needed to determine the optimal training and utilization protocols required to facilitate the effective incorporation of REBOA into military prehospital care capabilities.

Blood pressure monitoring in aeromedical care

We often wonder if we should place an arterial line before transporting a patient by air, so we were very interested to read the study by McMahon et al. 1 that found poor agreement between invasive and non-invasive mean and systolic arterial blood pressure readings, but with no clear diminution of accuracy during flight compared with measurements taken before transport. Perhaps, as could be inferred from the results, aeromedical transport per se is not an indication for invasive arterial pressure monitoring. However, we should like more details before being sure of this conclusion. Two hundred and fifty-one patients were eligible for the study by virtue of having arterial catheters in place. Of these, only 56 (22%) were included in the analysis. Patients were excluded if simultaneous measurements of intra-arterial (IABP) and non-invasive (NIBP) blood pressure were not possible for the duration of the transfer. Therefore, 195 patients presumably had one or other monitor ‘fail’. Knowing more about these patients and the modes of such failures would be very helpful. Could it be that NIBP measurement simply does not work in flight in more than 75% of patients? Secondly, the patients were transported by either fixed or rotary wing platforms. Vibration in each platform type is quite different, so it would be useful to analyse the data stratified by platform type. Even if McMahon's dataset is too small for definitive conclusions, this would facilitate a better subsequent study. It would be useful to know a little more of the statistical analysis that concluded no significant difference between pre-flight and in-flight readings. The data presented in Fig. 4 of the paper seem to show that in-flight NIBP readings were somewhat more random. For example, was there a difference in the proportion of readings that exceeded a clinically unacceptable threshold? It was also unclear how unwell these patients were. This might easily be analysed by reporting how many patients were receiving vasoactive medication. Vasopressors are known to affect the accuracy of radial vs femoral invasive pressures 2, 3. The authors have assumed that IABP is the ‘gold standard’ measurement, which is not unreasonable. In many parts of the world, invasive pressure monitoring is standard-of-care for patients requiring inotrope infusions, so the comparison of IABP and NIBP in transport becomes moot. Even if we still have little idea of optimal blood pressure targets in critical illness 4, the reference point by which this question might be answered will be IABP. However, there is some evidence that clinicians can recognise a poorly-representative arterial pressure waveform, and when they supplement their therapeutic judgments with non-invasive measurements, their patients receive fewer blood transfusions, vasopressor infusions and antihypertensive medications, without worse outcomes 5. Finally, it was unclear where the arterial catheters were sited. Radial artery catheters commonly over- or under-read femoral arterial pressure 2, 3 and if McMahon's patients had a mixture of catheter sites the variable correlation with NIBP they observed is less surprising. In summary, we think Mc Mahon et al. present an important question with immediate practical implications, but an incomplete answer suggesting the need either for further analysis of their data or a larger study with prespecified stratification.

Tactical Evacuation: Extending Critical Care on Rotary Wing Platforms to Forward Surgical Facilities

Tactical Evacuation: Extending Critical Care on Rotary Wing Platforms to Forward Surgical Facilities

Tactical Evacuation: Extending Critical Care on Rotary Wing Platforms to Forward Surgical Facilities

Tactical Evacuation: Extending Critical Care on Rotary Wing Platforms to Forward Surgical Facilities