Engineering topics

Santman, D. M.

Publications and source records attributed to Santman, D. M..

3 records

NASA NTRS1980

Some effects of cruise speed and engine matching of supersonic inlet design

An analytical study was conducted to determine the impact of flight Mach number on inlet type selection for a supersonic cruise aircraft. External and mixed-compression axisymmetric and two-dimensional inlets were considered. The internal contraction of the mixed-compression inlets was limited to achieve self-starting. At Mach 2.0, the axisymmetric mixed-compression inlet provided the best aircraft range. At Mach 2.3, the two-dimensional mixed-compression inlet was the most attractive if enough variable geometry were incorporated to minimize spillage during subsonic cruise. Increases in takeoff-to-cruise air flow ratio gave lower aircraft range.

Bangert, L. H.↗

NASA NTRS1980

Effects on inlet technology on cruise speed selection

The impact of cruise speed on technology level for certain aircraft components is examined. External-compression inlets were compared with mixed compression, self starting inlets at cruise Mach numbers of 2.0 and 2.3. Inlet engine combinations that provided the greatest aircraft range were identified. Results show that increased transonic to cruise corrected air flow ratio gives decreased range for missions dominated by supersonic cruise. It is also found important that inlets be designed to minimize spillage drag at subsonic cruise, because of the need for efficient performance for overland operations. The external compression inlet emerged as the probable first choice at Mach 2.0, while the self starting inlet was the probable first choice at Mach 2.3. Airframe propulsion system interference effects were significant, and further study is needed to assess the existing design methods and to develop improvements.

Bangert, L. H.↗

NASA NTRS1976

Transonic performance of Mach 2.65 auxiliary flow axisymmetric inlet

Transonic experimental performance for a large scale Mach 2.65 axisymmetric inlet model with auxiliary airflow systems are presented. The inlet model incorporated both centerbody and cowl auxiliary airflow systems. When the centerbody system was fully open the performance at the simulated compressor face was such that, at 0.10 total pressure distortion the total capture mass flow ratio increased 0.055 and 0.051 and the total pressure recovery increased 0.015 and 0.012 at Mach 0.9 and 1.3, respectively. Flow separation on the centerbody resulted in supercritical centerbody auxiliary throat flow prior to attainment of choked main duct throat flow. Cowl auxiliary airflow had a detrimental effect on compressor-face performance. To overcome the detrimental effect, alternate cowl auxiliary airflow systems are described for efficient merging of auxiliary and main duct airflows and for providing similar auxiliary and main duct throat choking characteristics.

Santman, D. M.↗