Efficiency of a prop goes up with larger diameter. So better make a bigger
2 blade prop (or even 1 blade) than a smaller 3 blade prop.
2014-02-11 19:51 GMT+01:00 Phedon Tsiknopoulos <phedon21t_at_yahoo.com>:
>
>
> How about a 3-bladed prop to reduce the unwinding speed, and head for 50
> minutes.
>
> Sent from my iPhone
>
> On Feb 11, 2014, at 5:21 AM, "mkirda_at_sbcglobal.net" <mkirda_at_sbcglobal.net>
> wrote:
>
>
>
> Slobodan Midic has a design that does that already, as well as Dr. Drela's
> info posted here. There is still a lot of room for experimentation and
> optimization with those designs. Drela's design has one drawback in that it
> applies torque a typical design may not be able to overcome. Offsetting the
> wing further may help, as may limiting the largest diameter a bit more. The
> hinges are also critical. Spring design for closing also becomes critical
> as the change comes over 160 degrees.
>
> By all means, experiment with these designs.
>
> Regards.
> Mike Kirda
>
> --- In Indoor_Construction_at_yahoogroups.com, Tapio Linkosalo
> <tapio.linkosalo_at_...> wrote:
> >
> > On Tue, Feb 11, 2014 at 12:36 PM, Phedon Tsiknopoulos
> > <phedon21t_at_...>wrote:
> >
> > >
> > >
> > > What if we have variable pitch as well as variable diameter?
> > >
> > >
> >
> >
> > Also that has been tried (change the pitch along changing diameter), but
> no
> > break-through on that either. Probably you would need to have variable
> > pitch distribution (VPD) prop for making the 50 mins.
> >
> >
> >
> > -Tapio-
> >
>
>
>
Received on Thu Feb 13 2014 - 03:20:40 CET