I have start to build a model which is a 40 cm rotor with four wings. It is a Darrius-varint expected to start itself. It shall have wings of 20 mm pipes and
airfolds attached, which is simply a plate bent over the pipe and formed a shape like a waterdrop. The airfolds in the model shall be easy to remove given possibility to test some shapes. The airfolds will be fixed. I estimate two weeks before I can show a picture of the model. I have tried put the design so it is expected to have help of winds facing a roof or a hill. I will test on a roof facing the main winds which here is east and west. The project spending is up to the model is done USD 50 (as I have to hire somebody for part of the work I am not able to do).
