STONewsArchive: Development of a validation model of a stealth UCAV
Title:
Development of a validation model of a stealth UCAV
Start_Publishing:
17/03/2021
Panel_Page:
SET
Page_ID:
3798
Main_Body_Multi:
NATO SET-252 - Development of a validation model of a stealth UCAV
Dr Harmen van der Ven
NLR – The Netherlands
One of the promises and concerns in today’s air warfare is the rapid development of unmanned combat aerial vehicles (UCAV). The use of UAVs has increased dramatically and the need to know their radar signature has become more and more evident. The electromagnetic scattering characterization of aircraft is one of the most challenging problems in military engineering. The interest in such an analysis is that the scattering characteristics of an aircraft, be it friend or foe, are the basic input for electronic warfare and detection/tracking algorithms. The characteristics can be obtained by both measurements and computations. Synergy between measurements and computations is growing. Measurements may be expensive or impossible to execute for enemy aircraft, or when the aircraft is still in the design phase. Computations require detailed knowledge of the aircraft geometry and materials and full-wave rigorous methods require significant computing times.
For a computational methodology to be useful, validation of the method by comparing with measured data is an essential prerequisite. In the past, methods have been validated for perfectly reflecting objects, both for academic and real-life bodies. Methods for stealth material have mostly been validated for academic bodies such as spheres, and the validation for real-life geometries is lacking. Validation for real-life geometries requires a well-defined (in terms of geometry and materials) validation model which is relevant (that is, the shape is that of an aircraft and materials are feasible). Development of such a model is not straightforward.
The main objective of the SET-252 group is to design and manufacture a validation model of a low-observable UCAV. The model is based on the computational model of AVT-251 and shown in the figure below. Using computational methods, the group has identified the radar signature hot spots and subsequently reduced the signature by application of radar-absorbing materials in inlet and on leading edges. With these theoretical studies, the group provides well-founded estimates on the radar detectability of typical U(C)AVs.
Parallel to the computational activities, the group designed the physical validation model. The validation model has a span of 3 meters (1:5 scale) and is designed for measurements at 10GHz. This corresponds with a real-life frequency of 2GHz, typical of surveillance radars. The midsection with inlet and exhaust accommodates space for a measurement turn table and is 3D printed. The wings are milled in foam. Midsection and wings can be disassembled before transport. Aluminium plates will be screwed to both wings and midsection. The wings will be attached to the midsection using a spring-loaded spar, which ensures that the components are tightly attached and the effect of the edge is minimized. The final design is shown in the figure below. The figure also shows the milled wings and 3D printed parts of the midsection. In 2021 the model will be assembled and coated with metallic paint and radar-absorbing material.
Actual measurements on the model will take place in a follow-on group. Then the measurements can be used to compare with the computations of the current group. Regardless, the pre-cursor computations of the current group already had an impact on the simulation tools of the partners. Cross-plotting of the results revealed the sensitivity of the results for certain numerical parameters for which the default setting is incorrect for the type of radar-absorbing material considered in the model. In this way, the collaboration has improved the tools of the NATO partners.
Page_Intro:
The main objective of the SET-252
group is to design and manufacture a validation model of a
low-observable UCAV. The model is based on the computational model of
AVT-251 and shown in the figure below. Using computational methods, the
group has identified the radar signature hot spots and subsequently
reduced the signature by application of radar-absorbing materials in
inlet and on leading edges. With these theoretical studies, the group
provides well-founded estimates on the radar detectability of typical
U(C)AVs.
HomePageImage:
2021-SET-252-home.jpg
HomePageBodyText:
NATO SET-252 - Development of a validation model of a stealth UCAV
Dr Harmen van der Ven
NLR – The Netherlands
One of the promises and concerns in today’s air warfare is the rapid development of unmanned combat aerial vehicles (UCAV). The use of UAVs has increased dramatically and the need to know their radar signature has become more and more evident. The electromagnetic scattering characterization of aircraft is one of the most challenging problems in military engineering. The interest in such an analysis is that the scattering characteristics of an aircraft, be it friend or foe, are the basic input for electronic warfare and detection/tracking algorithms. The characteristics can be obtained by both measurements and computations. Synergy between measurements and computations is growing. Measurements may be expensive or impossible to execute for enemy aircraft, or when the aircraft is still in the design phase. Computations require detailed knowledge of the aircraft geometry and materials and full-wave rigorous methods require significant computing times.
For a computational methodology to be useful, validation of the method by comparing with measured data is an essential prerequisite. In the past, methods have been validated for perfectly reflecting objects, both for academic and real-life bodies. Methods for stealth material have mostly been validated for academic bodies such as spheres, and the validation for real-life geometries is lacking. Validation for real-life geometries requires a well-defined (in terms of geometry and materials) validation model which is relevant (that is, the shape is that of an aircraft and materials are feasible). Development of such a model is not straightforward.
The main objective of the SET-252 group is to design and manufacture a validation model of a low-observable UCAV. The model is based on the computational model of AVT-251 and shown in the figure below. Using computational methods, the group has identified the radar signature hot spots and subsequently reduced the signature by application of radar-absorbing materials in inlet and on leading edges. With these theoretical studies, the group provides well-founded estimates on the radar detectability of typical U(C)AVs.
Parallel to the computational activities, the group designed the physical validation model. The validation model has a span of 3 meters (1:5 scale) and is designed for measurements at 10GHz. This corresponds with a real-life frequency of 2GHz, typical of surveillance radars. The midsection with inlet and exhaust accommodates space for a measurement turn table and is 3D printed. The wings are milled in foam. Midsection and wings can be disassembled before transport. Aluminium plates will be screwed to both wings and midsection. The wings will be attached to the midsection using a spring-loaded spar, which ensures that the components are tightly attached and the effect of the edge is minimized. The final design is shown in the figure below. The figure also shows the milled wings and 3D printed parts of the midsection. In 2021 the model will be assembled and coated with metallic paint and radar-absorbing material.
Actual measurements on the model will take place in a follow-on group. Then the measurements can be used to compare with the computations of the current group. Regardless, the pre-cursor computations of the current group already had an impact on the simulation tools of the partners. Cross-plotting of the results revealed the sensitivity of the results for certain numerical parameters for which the default setting is incorrect for the type of radar-absorbing material considered in the model. In this way, the collaboration has improved the tools of the NATO partners.
Created at 17/03/2021 13:23 by ad.rodes
Last modified at 17/03/2021 13:23 by ad.rodes
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