Powerplant Sizing
Description
This page will include refined sizing and major dimensions of your concept based on the performance parameters previously determined. It will also include details about the engines that will be used for the design and the required power.
Sizing Refinement
What are the major dimensions now required for the wings after performance matching? Are they different than they were before? Have any other sizing parameters changed?
Refined dimensions
| Parameter | Imperial | Metric |
|
Wing Span |
41.8 ft | 12.74 m |
|
Wing Area |
286.348 ft2 | 26.6 m2 |
|
Wing Aspect Ratio |
6.101 | - |
|
Wing Sweep Angle |
4.8 Degrees | - |
|
Leading-Edge Sweep |
7.3 Degrees | - |
|
Trailing-Edge Sweep |
2.8 Degrees | - |
|
Mean Chord Length |
5.989 ft | 1.825 m |
|
Horizontal Stabilizer Location |
20.9 ft | 6.37 m |
|
Vertical Stabilizer Location |
20 ft | 6.1 m |
|
Horizontal Stabilizer Area |
45.61 ft2 | 4.24 m2 |
|
Vertical Stabilizer Area |
24.77 ft2 | 2.30 m2 |
|
Aircraft Wetted Area |
1305 ft2 | 121.24 m2 |
Engines and Power
According to the performance matching, the maximum power loading for the aircraft to perform VTOL is 4lb for every horsepower. Considering the aircraft was estimated to have a maximum take-off weight of 8767 lb, this means that the aircraft would require a total power of roughly 2191.9 hp. To provide sufficient power, a pair of Pratt and Whitney PT6A - 67F was chosen to power the aircraft. the engine has the following engine specifications as obtained from the European Union Aviation Safety Agency [1].
P&W PT6A - 67F
| Parameter | Imperial | Metric |
| Overall Length | 75.31 inches | 1913.1 mm |
| Overall Diameter | 18.35 inches | 466.1 mm |
| Dry Weight | 571.66 lb | 259.3 kg |
| Max Continuous Power | 1700.416 hp | 1268 kW |
| MAX Turbine output RPM | 1700 RPM | 1700 RPM |
| MAX Torque Continuous | 5252.2 lb/ft | 7121 Nm |
As seen in the table, a single turbine engine can produce roughly 1700 hp. In the application of the "Niska" however, two of the specified engine is required to be installed on the aircraft. Overall, with two turbine engines, the aircraft would produce roughly 3400 hp which meant the aircraft would have a power loading of 2.68 lb/hp. While this may initially seem to be overpowered for the aircraft, these engines are necessary especially considering the VTOL requirement of the aircraft. With the power available, it allows the aircraft to directly take off vertically without relying upon most of its lift from ground effect.
Figure 1, PT6A 67F turbine engine [2].
References
[1] European Union Aviation Safety Agency, “PT6A-67 Series Engine TYPE-CERTIFICATE DATA SHEET,” 2019. [Online].
[2] “PT6A-67F Capabilities,” euravia. [Online]. Available: https://www.euravia.aero/engine-detail/pt6a-67f?locale=en. [Accessed: 23-Jun-2021].