Loading...
Please wait, while we are loading the content...
Similar Documents
A wind-tunnel investigation of parameters affecting helicopter directional control at low speeds in ground effect
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Mantay, W. R. Young Jr., W. H. Yeager Jr., W. T. |
| Copyright Year | 1974 |
| Description | An investigation was conducted in the Langley full-scale tunnel to measure the performance of several helicopter tail-rotor/fin configurations with regard to directional control problems encountered at low speeds in ground effect. Tests were conducted at wind azimuths of 0 deg to 360 deg in increments of 30 deg and 60 deg and at wind speeds from 0 to 35 knots. The results indicate that at certain combinations of wind speed and wind azimuth, large increases in adverse fin force require correspondingly large increases in the tail-rotor thrust, collective pitch, and power required to maintain yaw trim. Changing the tail-rotor direction of rotation to top blade aft for either a pusher tail rotor (tail-rotor wake blowing away from fin) or a tractor tail rotor (tail-rotor wake blowing against fin) will alleviate this problem. For a pusher tail rotor at 180 deg wind azimuth, increases in the fin/tail-rotor gap were not found to have any significant influence on the overall vehicle directional control capability. Changing the tail rotor to a higher position was found to improve tail-rotor performance for a fin-off configuration at a wind azimuth of 180 deg. A V-tail configuration with a pusher tail rotor with top blade aft direction of rotation was found to be the best configuration with regard to overall directional control capability. |
| File Size | 14643309 |
| Page Count | 177 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19750003859 |
| Archival Resource Key | ark:/13960/t4tj38w4w |
| Language | English |
| Publisher Date | 1974-11-01 |
| Access Restriction | Open |
| Subject Keyword | Aircraft Design, Testing And Performance Tail Assemblies Helicopters Wind Tunnel Tests Rotor Aerodynamics Ground Effect Aerodynamics Directional Control Aerodynamic Characteristics Helicopter Wakes Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
