Manoeuvre Response of High Speed Compound Helicopters.
Abstract
The next generation of rotorcraft will have to satisfy the appropriate handling qualities requirements before entering service. Many of these vehicles will operate at significantly greater speeds than the conventional helicopter and will there have different capabilities than current helicopters. Due to the different capabilities of the compound helicopter, it is possible that new Mission Task Elements (MTEs) need to be developed to assess the handling qualities of this type of helicopter. It is also possible that existing MTEs may be suitable without modification. Overall, it seems necessary to review the US Army s current handling qualities specification, ADS-33, and determine the suitability of the current MTEs for compound vehicles. The broad aim of the study is to assess the performance of compound helicopters during manoeuvring flight. More specifically, a simulation study of compound helicopter configurations flying ADS-33 Mission Task Elements. There will be two objectives: firstly the capabilities of the compound vehicle is compared with those of a conventional helicopter, and secondly, the suitability of the current MTEs for compound vehicles is assessed. The aim is achieved by using the flight dynamics tool of inverse simulation. Inverse simulation is the process of inverting the dynamic model to recover the inputs required to produce a desired response (usually in the form of a flight path trajectory). Although the outputs of inverse simulation and controller design are identical, inverse simulation does not require detailed knowledge of the underlying model and is thus extremely effective for investigating performance and control strategies. Using inverse simulation the manoeuvre of interest becomes the input to the simulation, and the vehicle response and pilot control activity required to fly it are computed. The mathematical model used for the research is a 6 degrees of freedom nonlinear model with a disc representation of the main rotor. This is a very well established formulation, which provides valid and usable results over a wide range of flight conditions. Part of the research concentrated on improving the mathematical model, however the main focus of the proposed research is on performance during manoeuvres. The research uses an existing data-set of the UH-60A helicopter, as a starting point. This configuration is used for two primary reasons. Firstly, the data-set is in the public domain thereby allowing dissemination of results. Secondly, the UH-60A helicopter falls into the utility helicopter category, which is the type of helicopter the Joint Multi Role (JMR) programme is targeting. The first phase of the study involved developing and validating the UH-60A mathematical model. This was achieved using the UH-60 flight catalogue document. Next, the UH-60A configuration was converted into compound helicopter configurations using basic design techniques. Thereafter, the inverse simulation algorithm is applied to the compound configurations giving the appropriate control displacements, state time histories along with performance related parameters such as power required. By varying the severity of the manoeuvre, and monitoring the compoundÕs performance, limiting manoeuvres were identified. The results of the research study highlight the capability of compound helicopters in low speed acceleration manoeuvres. These results can be used to redefine low speed acceleration manoeuvres in the new update to the ADS-33 specification. The results also indicate some information about the potential design issues with the compound helicopter.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1510439
Entities
People
- Douglas Thomson
Organizations
- Army Contracting Command
- United States Army
- University of Glasgow