|Acquisition Program: ||PEO(W) Strike Weapons and Unmanned Aviation (pre-milestone A, ACAT TBD)|
| ||RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is “ITAR Restricted”. The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the “Permanent Resident Card”, or are designated as “Protected Individuals” as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.|| Objective: ||Develop, design and demonstrate alternative flight control systems that can reduce or eliminate the need for fins or wings on high supersonic cruise missiles (Mach = 4 to 5).
|| Description: ||Control surfaces for high speed vehicles greatly complicate the design of a high speed vehicle, due to conflicting design requirements that significantly impact vehicle performance.. At lower speeds, large control surfaces are required to maintain control authority, while at higher speeds control surface effectiveness decreases, so large surfaces are still required. However at high speeds the control surfaces must also be thin to minimize drag. Structurally, this presents a series of challenges as the large thin control surfaces are under significant aerodynamic and heating loads during high speed flight operations and contribute a significant amount of drag to the overall system. Additionally, for tactical missiles, control surfaces often need to be folded or retracted in some manner in order to facilitate integration onto the launch platform (aircraft or launch cell on a ship or submarine).
All of these problems demonstrate the need to develop alternative control systems that can be as effective as typical aerodynamic control systems, but do not over-burden the vehicle in other areas. There are many factors that must be considered in order to develop a useful method for controlling high speed vehicles:
• Often high speed vehicles must have controllability at subsonic speeds during take-off or launch and during acceleration to high speed. An alternative control system must maintain sufficient control authority of a wide speed range (sufficient control authority over a speed range from Mach 0.5 to Mach 4.5 for a representative axi-symmetric missile body with a center-of-gravity at x/L = 0.6).
• Controls for maneuvering and trimming the vehicle need to be considered to make an alternative control system viable.
• The cost to the vehicle system must be considered when developing an alternative control system since most applications will be in expendable vehicles.
• The goal is to have the same or less impact on weight, drag and power required as a conventional fin control system with equivalent control authority.
• Because any reduction in control surface size may assist in the design of a high speed missile (particularly for the volume and weight limited cases), systems that augment conventional aero control surfaces may be applicable if there is benefit to the vehicle as a whole (such as reduced complexity, weight, etc.).
|| ||PHASE I: Develop a concept for an alternative control system that demonstrates control authority at Mach 4 to Mach 5 and over a wide range of speed regimes, from Mach 0.5 to 4.5
|| ||PHASE II: Develop and demonstrate a prototype system that demonstrates desired control authority with reasonable system attributes such that the control system could be integrated into a missile sized vehicle at similar cost to conventional controls (size, weight, power requirements, etc.) at Mach 4 to Mach 5, and over a Mach range from M = 0.5 – M = 4.5.
|| ||PHASE III: Insert the product into a candidate high-speed missile airframe.
PRIVATE SECTOR COMMERCIAL POTENTIAL/|| ||DUAL-USE APPLICATIONS: This system could be applied to any private/commercial subsonic air vehicle or to subsonic/ supersonic unmanned air vehicles. In addition, the same methods of flow control could be applied to several other types of flows such as internal engine flow control, thrust vectoring, or other non-intrusive applications.
|| References: ||1. Rattlrs program fact sheet, http://www.onr.navy.mil/media/extra/fact_sheets/rattlrs.pdf
2. Signal magazine, May 2006, "Missiles Aim for Mach 4 Capability"
3. Massey, K, Silton, S., “Testing the Maneuvering Performance of a Mach 4 Projectile.” AIAA-2006-3649, 24th AIAA Applied Aerodynamics Conference, San Francisco, California, June 5-8, 2006
4. Patel, M, Prince, T, Carver, R, DiCocco, J, and Lisy, F, “Deployable Flow Effectors for Phantom Yaw Control of Missiles at High Alpha.” AIAA-2002-2827, 1st Flow Control Conference, St. Louis, Missouri, June 24-26, 2002
5. Patel, M, Sowle, Z, Ng, T, Toledo, W, “Hingeless Flight Control of a Smart Projectile Using Miniature Actuators.” AIAA-2005-5258, 35th AIAA Fluid Dynamics Conference and Exhibit, Toronto, Ontario, June 6-9, 2005|
|Keywords: ||controls; flight control system (FCS); flow control; unconventional controls; alternative flight controls|