JavaProp - Tips, Tricks and Errors
- The best performance in the design point is achieved by selecting the
maximum L/D of the selected airfoils, but the off design performance
may be poor.
- To get wider blades, you have to decrease the lift coefficient (resp.
angle of attack) or the rpm value. To get wider tips, decrease the
angle of attack at the tip only.
- For better low speed, off design performance, you should select a lower
design Cl for the inboard section. This will reduce the
blade angle in this region and create a design with wider blades, delaying the
stall when the flight speed is decreasing.
- To calculate the thrust of your prop/engine combo under different
operating conditions, you need coefficients of the propeller and also the
engine performance curve (power vs. velocity of rotation).
[for more info: look here]
- To design a hydroprop, you have to consider the different fluid
properties.
[for more info: read this]
Conversion Hints
| Power |
1 hp |
= |
745.7 W |
|
1000 W |
= |
1.341 hp |
| Force |
1 lbf |
= |
4.448 N |
|
1 N |
= |
0.2248 lbf |
| Mass |
1 lbm |
= |
0.4536 kg |
|
1 kg |
= |
2.205 lbm |
| Length |
1 foot |
= |
0.305 m |
|
1 m |
= |
3.281 feet |
| Length |
1 inch |
= |
0.0254 m |
|
1 m |
= |
39.37 inches |
| Speed |
1 mph |
= |
0.4469 m/s |
|
1 m/s |
= |
2.237 mph |
I will leave the conversion factors for those, who are
measuring the propeller diameter in townships or teaspoons,
mass in scruples and force in kips as an example for the
reader...