Analysis of Polymeric Composite Materials application for helicopter airframe design
Design, construction and manufacturing of flying vehicles
1. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
2. Company "Kamov", 26/1, Garshina str., Tomilino, Moscow region, 140070, Russia
The studies conducted in the 1980s of the 20th century by a number of the US aircraft manufacturers under project administration of U.S. Air Force Materials laboratory, has shown that practical application of polymeric composite materials (PCM) in military airplanes and helicopters design results in not only considerable decrease of their weight and cost, but also in higher survivability, maintainability, many other improvements.
In the late 70s of the 20th century the U.S. Government, by request of the Air Force, invested in research work and Advanced Composite Airframe Program (ACAP) to demonstrate helicopter weight and cost reduction potential with maximum wide PСM application in its design. The ACAP program results were extremely successful. S-75 and D-292 demonstrators made clear the advantages of PСM application in the helicopter airframe structure achieved by maximum structure integration and use of large-size three-layered panels with honeycomb core, special shape of external panels to reduce the radar signature, as well as the implementation of the parts highly resistant to battle damages and capable of energy absorption at crash landing.
At about the same time, the helicopter development projects known today as Ka-50, Ka-226, Ka-60/62 were in progress in our country. From the very beginning wide application of PCM in the helicopter structure and, first and foremost, in the airframe was the target goal.
PCM implementation in the fuselage structure purported weight reduction, labor hours and industrialization cost reduction, as well as lifetime and combat survivability increase, and operational costs reduction. This task was successfully solved. Based on world-wide successful results of PCM implementation in primary and secondary helicopter airframe structures, the 90s of the 20th century marked a consistent trend among all key helicopter manufacturers to extensive PCM application in new helicopter airframes. That is why when the development of Ka60/62 helicopter project was initiated in the late 80s, Mr. S.Mikheev, Kamov Company General Designer, set up the task of extending PCM application in the fuselage design up to 60‒70%. The manufacturing technological problems of large-size integral three-layers panels made from PCM were solved successfully. At the same time the manufacturability and costs analysis of the proposed technical solutions led to refusal of PCM application in the critical parts and assembles of Ka-62 fuselage.
Based on the analysis of design and manufacturing experience on helicopter airframe parts made of PCM, the paper offers substantiations and main conclusions on PCM wide-scale implementation in the helicopter design. Advantages and disadvantages of PCM application are demonstrated and main present-day obstacles on the way of wide PCM implementation in Russia in the helicopter design are outlined. Possible ways of their overcoming are suggested as well.
Keywords:composite material, fatigue and static strength, layers laminate structure, energy-adsorbing structures, whole-composite fuselage, integral panels, manufacturability
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