• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.215-223
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• 2010

In order to develop an precision aerial pesticide application system to be attached to an unmanned helicopter which can be applied to small lots of land, this study analyzed the flowing and spraying characteristics of the spray droplets by the main rotor downwash by setting the application conditions at the flight altitude of 3 m, the diameter of main rotor of 3.1 m, the boom length of around 2.8 m, and the spraying rate of 8 L/ha. The results of this study are summarized below. Through analysis of the covering area ratio of the spray droplets by main rotor downwash by nozzle type, boom with tilt angle and height, it was found that the covering area ratio of the twin flat-fan nozzle of around 25% was more uniform than other types of nozzle, also boom with $10^{\circ}$ tilt angle and spraying height of 3 m was shown to be the appropriate conditions for aerial application of pesticides. It was found that the nozzle position to minimize the scattering loss of spray droplets due to vortex phenomenon at both ends of the main rotor was around 10 cm from the end of the main rotor. An application test for the aerial pesticide application system attached to the HUA-ACEI unmanned helicopter developed by the Rural Development Administration showed that the range of covering area ratio of the spray droplets was 10-25%, and the spraying width was approximately 7 m when over 10% of covering area ratio was considered for valid spraying.

• Korean journal of applied entomology
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• v.62 no.1
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• pp.43-48
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• 2023

The efficacy of spinetoram sprayed from an unmanned helicopter to control two insect vectors of pine wood nematodes, Monochamus alternatus and M. saltuarius was assessed. By using a ULV (Ultra Low Volume) sprayer, the mortality rates of phenthoate, bifenthrin, etofenprox, and diflubenzuron, which are registered for use against coleopteran insects, indoxacarb and spinetoram, which are registered for use against lepidopteran insects, were evaluated for efficacy as aerial spraying agents. The ULV test, using 33- and 55-fold dilutions of phenthoate, bifenthrin, indoxacarb, and spinetoram demonstrated a 100% insect mortality rate upon contact and feeding mortality on the third day after treatment, while etofenprox and diflubenzuron exhibited a slightly lower mortality rate than the remaining compounds. Consequently, spinetoram was selected as a candidate pesticide for aerial spraying and its efficacy to control the insect vectors was assessed. The x 33 dilution of spinetoram resulted in a 98.6-100% control efficacy against two insect vectors. However, risk assessment for bees following aerial spraying will be necessary before applying the pesticide to control insect vectors.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.420-430
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• 2005

As the pine wilt disease spread rapidly over Korea in recent, aerial pesticide spraying to the infected pine stands increased abruptly. The increasing aerial pesticide application for control of the disease would result in disturbance of soil ecosystem in pine stands. This study was conducted to assess the disturbance, using field experiment in pine stands of Hongleong experimental forests in Seoul with BACI experimental design with three sprayed plots and three unsprayed plots of $25m^2$. We sprayed fenitrothion of 0.0335 kg a.i./ha over each of the sprayed plots, being the same as the pesticide residues of litters after aerial spraying. The pesticide had been applied on 4 June, 11 June, and 29 June in 2002, comparable with the dates of the aerial spraying in the previous year in Busan. We monitored population of soil organisms including arthropods, fungi, bacteria, and actinomycetes at two sampling days before pesticide application, at two sampling days during the application season, and at three sampling days after last application for two months since late May in 2002. The pesticide applications did not make any significant effect on the population of arthropods, fungi, bacteria, and actinomycetes in soils and on the structure of soil organism community, showing low probability of significant effects of the aerial pesticide application on soil organisms in pine stands.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.403-413
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• 2008

This study was conducted to select excellent tank mix combinations of pesticides for aerial application by manned helicopter. Among 209 pesticide combinations of 3-way tank-mixing for aerial application, a total of 93 recommendable combinations including tricyclazole SC+validamycin-A SL+imidacloprid SL were finally selected for the simultaneous control of key pests on paddy rice such as blast, sheath blight, brown planthopper and moth. The selected combinations were not phytotoxic to rice plants and nearby non-target crops, and excellent in physicochemical properties of ultra low volume (ULV) spray solutions. The efficacies on sheath blight, brown planthoppers and white-backed planthoppers of pesticides sprayed by aerial application were similar to those of pesticides by conventional spraying. Total cost of aerial application in paddy rice was very economical as one fourth level of that of conventional spraying.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.182-187
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• 2006

Aerial application using an unmanned agricultural helicopter can reduce labor and pollution. The development of an agricultural helicopter became urgent for both precise and timely spraying. In this study, a rotor system for unmanned helicopter capable of 20 $kg_f$ payload, was developed and lift capability was evaluated. A lift force over the dead weight of the helicopter was obtained at the pitch angle of $6^{\circ}$. As the pitch angle increased to $8^{\circ}\;and\;10^{\circ}$, the total lift increased to $74{\sim}81\;kg_f\;and\;86{\sim}93\;kg_f$, respectively. A range of engine speed at the rated flight condition, lifting mean payload of 23 $kg_f$ was determined. The data acquired from this study will be used for designing tail system and RF console in the next stage of the research. The rated lift capability was enough for loading 20 liters of spray material including spraying equipments.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.230-236
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• 2007

In this study, a tail rotor system for an agricultural RF controlled helicopter was developed and tested. This study concluded the mechanical development of the 'Agro-heli' by completing the tail rotor system and its radio console. The RF control system was closely related with the tail system for the control of flying attitude. The thrust of the tail system balance off the reaction torque, created by the main rotor. Lifting tests with and without the tail system were compared for estimating the consumption of power. The tail system would use $4{\sim}5%$ of the total power which was in an acceptable range. Flying performance and attitude was visually inspected. It showed reliable and safe control during the distance flying trials and could be adapted for utilization in aerial applications. Aerial application using an RF controlled agricultural helicopter may make precise and timely spraying possible.

• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.302-309
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• 2010

Aerial application using an unmanned agricultural helicopter would allow precise and timely spraying. The attitude of a helicopter depends on a number of dynamic variables for roll-balanced flight. Laterally tilting behavior of a helicopter is a physically intrinsic phenomenon while hovering and forwarding. In order to balance the fuselage, the rotor should be counter-tilted, resulting in the biased down-wash. The biased spraying toward right side causes uneven spray pattern. In this study, a raised tail rotor system for the roll-balanced helicopter was studied. Thrust of the tail rotor system was measured and theoretically estimated for the fundamental database of the roll-balanced helicopter design. The estimated tail thrust and roll-moment would be used to design the raising height of tail rotor and roll balancing dynamics. The unmanned agricultural helicopter required the tail rotor thrust of about 39.2 N (4.0 kgf) during hovering with a payload of 235.4 N (24 kgf). A raised tail rotor system would compensate for the physical tilt phenomena. A further attitude control system of helicopter would assist roll-balanced aerial spray application.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.95-101
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• 2006

Present chemical application system using a power sprayer has been a labor intensive, ineffective and shirking task in farming. Therefore, a small RF controlled (unmanned) helicopter was suggested to replace the conventional spray system. The aerial application using the unmanned helicopter has been already utilized in Japan, where total area applied up to 704,000 ha in 2005. In this article, the status and cost analysis on the unmanned agricultural helicopter were studied. The aerial application using the agricultural helicopter helps precise and timely spraying and reduces labor intensity and pollution. The field capacity of the helicopter was found to be 60-70 ha a day. The break even point was estimated near the operating area of 750 ha annum. The development of an agricultural helicopter was necessary for taking advantages of both technique and economy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.597-604
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• 2016

The aim of this study was to prevent the decrease in crop output by disease and insect pests and excessive spraying of agricultural pesticides by application uniformity. A 3m height and 15km/h speed is difficult to maintain with an unmanned helicopter for aerial application, which has been affected by the controlling habits and methods or environmental factors, such as changes in the wind. Therefore, in this study, an aerial application system was design to be attached to an unmanned helicopter, which can allow a controlled application width and spray rate automatically and verified experimentally using Rmax of MS-AVIATION. The size of agricultural land was 50 m2 and nine water sensitive cards were arranged at 1.25m intervals in 5 rows with each row having a 10m interval from the position of 5m. The unmanned helicopter was flying at speeds ranging from 7.2km/h to 17.6km/h and heights ranging from 2.32m to 3.47m. The proposed aerial application system allowed application uniformity by making a valid spraying area of 7.5 m2 with 46423 particles distributed on average.

• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.17-29
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• 1989

This study was conducted to evaluate the behavior in the water and the impact on aquatic organisms following aerial application of two insecticides in the forest, cyfluthrin and trichlorfon, to control the alder leaf beetle. As active ingredients, 25g of cyfluthrin and 536g of trichlorfon per ha were diluted seperately into 30L of tap water, and applied with a helicopter to the study areas. A model stream study was also conducted in a stream located adjacent to the study area in order to confirm the impact of insecticides on aquatic invertebrates. Cyfluthrin residues in water were $0.62{\mu}g/L$ (1st. application) and $78{\mu}g/L$ (2nd application) immediately after spraying. and decreased, to a non-detectable level after one day, while trichlorfon residue increased to $30.7{\mu}g/L$ one day after spraying and fluctuated for 22th day depending on precipitation after spraying. Cyfluthrin application rapidly increased the number of some drifting aquatic invertebrates during 24-hour period immediately after spraying, but had no effects on the other aquatic organisms such as fish and zooplankton. The largest increase in the number of drifting organisms following application of cyfluthrin was shown by Ephemeroptera, and followed by Trichoptera, Coleoptera, and Diptera. However, trichlorfon little affected the number of drifting aquatic invertebrates and zooplankton population.