Modeling screw propeller aircraft in heliciel
Tutorial design of a screw propeller plane (1)
We will see in this tutorial how to build an airplane screw propeller with HELICIEL. Heliciel allows construction of the geometry and analysis of the screw propeller's performances . A blade design, with profiles and pitch can be edited. A 3D model is also performed and prototyping will be possible, using the IGS blade file in a cad and prototyping machines. This screw propeller project will of course be tested without endangering the safety of persons!

 

Open a model airplane screw propeller in héliciel

ouvrir projet helice

 

Data to collect (here we took a scale model for example) before starting the construction of our screw propeller are:

Enter the "Project specifications"

Tab 1: Project specifications

fluide helice

You should get those fluid parameters:

parametres helices fluides

point de fonctionnement helice

In theTab 2 "Blade geometry" we will enter the dimensions of the blades of the propeller that we wish to build:

 

Tab 2.1 Blades Dimensions:

longueur pale

geometrie pale

Warning: For each modification chord it is imperative to update the distribution of cords by clicking "Linearize". You can then modify this distribution with the cursor. If you want to store a distribution, note the distribution equation, so you can apply it in a future adjustment .....

 

profil naca1408

We could determine the number of blades, but we will study later the number of blades at the optimization of the screw propeller.
Now we just have to rebuild our blade and test its performance by click onhelice heliciel) : This function builds the twist of our propeller blade optimized for the operating point described by the speed and the fluid velocity.
The result pane shows the performance of our propeller and the 3D prototype tab is updated.

vrillage pale

Looking more closely at the performance we will check our our thrust and power correspond to the needs of our aircraft:

performance pale helice

A 120 km / h we estimated that our plane generates a drag of 30 newtons. we found the engine torque curve at 800 rpm was 1.9 Nm With the formula given above we also know that the power of our engine at 8000 rpm is (1,9 X 8000) /9550 =1,59 Kw =1590 watts
We see that our propeller generates a thrust of 22 newtons, with a torque of 1.1 newton and a shaft power of 947 watts.
The calculated thrust ( 22 newtons ) is slightly less than the estimated drag (30 newtons) we estimate that our plane will not reach the required speed, As we have some power margin , engine power (1590 watts), is greater than the shaft power (947 watts), we can try to increase the rotational speed (go to 10 000 rpm) to increase thrust:

helice avion 10 000 rpm

 

And we get our new thrust 33 newtons at 10,000 rpm

performances helice

We note that the power required from the shaft increased to 1456 W and our load torque to the propeller shaft is 1.4 Nm.

We have chosen the way of the power to increase our thrust, We could have may be in these power save period, try to optimize our propeller! We'll see how to optimize our airplane screw propeller in the Tutorial screw propeller aircraft design (2)