KD 285 reviewed

Report KD 285 about the Gö 711 airfoils has been reviewed. A new chapter 4 has been added in which the moment coefficient Cmh is given around point H which is lying at 0.3 * c from the airfoil nose and half way the blade thickness.

KD 463 reviewed

Report KD 463 in which the aerodynamic characteristics of four Gö airfoils are given, has been changed. The Cm0.2-alfa curve has been added to figure 14 about the Gö 623 airfoil. A new chapter 5 has been added and figure 15 out of this chapter gives the curves for the Gö 624 airfoil.

KD 503 reviewed

Report KD 503 is reviewed in which an alternative 4-pole, PM-generator for the VIRYA-3 or the VIRYA-3B3 is described. A new chapter 4 has been added in which it is investigated if in stead of an Indian motor housing, it is possible to use a housing according to IEC norm. I is possible but only if a new stainless steel shaft is used.

KD 683 reviewed

Chapter 5 of report KD 683 has been reviewed. Three alternative armature constructions are given in this chapter.

KD 690 added

Report KD 690 has been added to the menu KD-reports. The tittle of this report is: “Ideas about a 4-pole permanent magnet generator for the VIRYA-2S windmill using the housing of a 4-pole, 3-phase, 0.75 kW asynchronous motor frame size 80 and 4 neodymium magnets size 80 * 20 * 10 mm. Design report of the rotor (lambda design = 4.5, B = 3, stainless steel blades)”.

Advantages of these generator are that the magnet costs are rather low (about € 28) and that the maximum torque level is that high that the generator can be used as a brake in combination with the VIRYA-2S rotor and the hinged side vane safety system.

KD 679 reviewed

Report KD 679 about the 8-pole VIRYA-1 PM-generator has been reviewed. The generator measurements and the discussion about the measurements which were originally given in report KD 678 are now also given in chapter 9 and 10 of report KD 679. So the drawings of the generator and the measurements are now available in the same report.

KD 678 reviewed

A new chapter 8 has been added to report KD 678 about the VIRYA-1.02. In this chapter, an alternative stator is described for which the coils have no front and back flange. The coils are therefore thinner and the air gap in between the magnets and the steel stator disk can be reduced by 2 mm. This results in a stronger magnetic flux through the coils. The Pmech-n curve of the generator will therefore shift to the left resulting in a better matching in between rotor and generator and in a higher maximum power.

KD 439 reviewed

Report KD 439, in which the pendulum safety system with a torsion spring is described, has been reviewed. The chapter in which the moment equations are derived for a steel rotor with blades with a 7.14 % cambered airfoil, is cancelled because such a rotor will be too heavy. A new chapter 6 has been added in which the use of the VIRYA-5.2 rotor and generator is investigated.

KD 377 reviewed

Report KD 377 from 2008 describes the pendulum safety system. Chapter 6 of this report, in which alternatives are described, has been changed somewhat.

KD 684 added

Report KD 684 has been added at the menu KD-reports. The tittle of this report is: “Derivation of the formula for the cone angle epsilon for a constant chord blade which is connected to the hub by a hinge”. The formula for the cone angle epsilon was already derived in report R 409 D from 1980 but as this report is written in Dutch and no longer available, the derivation is now given in this public report KD 684. The formula is used to calculate the bending stress at the blade root of for instance the VIRYA-3B3 rotor as described in chapter 8 of report KD 484.