Solar boat prop build problems


#1

We are 2 students working on the new propellors of our solar boat. Our goal is to design new props that are as efficient as possible.

The specs of our boat are:

Motor: PMG-132 on 30V
Max diameter: 420mm
Design velocity: 3,5 m/s
Number of blades: 2
RPM: 850 1/min

It is an 8 meter long solar boat which has 5 panels that deliver 950 Watt on average to the propellers with peaks up to 1.6kW when sunny and dips to 500 Watt when clouded. This is the multi analysis card in Javaprop:

We made a design in JavaProp with the airfoils of the designer of Javaprop.
We used the following Airfoils and angles of attack:
r/R=0,00 - airfoil: MH126 - AoA: 7*
r/R=0,333 - Airfoil: MH112 - AoA: 3,75*
r/R=0,667 - Airfoil: MH114 - AoA: 3,5*
r/R=1,00 - Airfoil: MH116 - AoA: 4,5*

The problem with the design is that it came out too thin and has a very small chord so we won’t be able to manufacture the props. We tried various things to get a thicker and bigger blade but to no avail.
Can somebody help us with this? We are a bit stuck here and hope that maybe you guys could help us. Does somebody know what the problem is or what we are doing wrong?

We would like to hear your thoughts on this.


#2

Sorry to ask an obvious question but did you switch the program from “air” to “water”?
From VEFOIL on a previous post: http://www.diy-electric-hydrofoil.com/java-prop/#!/up


#3

Yes we did, with air the lift coefficient is too low to work with.