Thanks LeRoy for reminding me. I retitled the videos to give credit to Jeff Annis. My apologies. I remember Jeff saying that he had invented the variable pitch prop that's on the model in the video!
--- In Indoor_Construction_at_yahoogroups.com, LeRoy C Cordes <lcordes@...> wrote:
>
> I'll mention it to him Wednesday if he's at Racine.
>
> LeRoy Cordes YOLO
> Chicago, Illinois
> AMA 16974
> In God We Trust
>
> On Thu, 26 Jan 2012 21:39:19 -0000 "Yuan Kang Lee" <ykleetx_at_...>
> writes:
> > That's very interesting to hear. Can you contact him to join the
> > Yahoo! Indoor group?
> >
> > --- In Indoor_Construction_at_yahoogroups.com, LeRoy C Cordes
> > <lcordes_at_> wrote:
> > >
> > > Kang, I know I replied to this before but I just confirmed that
> > the flyer
> > > you asked about in the video was Jeff Annis who Ray Harlan
> > recently
> > > attributed the pioneering work on the VP for indoors. I knew he
> > was a
> > > recent returnee to indoor but didn't know about his credentials
> > other
> > > than his beautiful planes.
> > >
> > > This is the excerpt from Ray Harlan's email:
> > > "The earliest concept of a VP for indoors that I know of is on p.
> > 74 of
> > > the '37 Zaic yearbook (same page as the torque burner). It is by R
> > Hammer
> > > and uses a compression spring and bent wires through the prop hub
> > to
> > > effect what looks to be decreased pitch with increased motor
> > tension.
> > > Perhaps Zaic didn't draw it correctly.
> > >
> > > However, the real pioneer of workable VP props was Jeff Annis. He
> > > puplished the paper "Torque Variable-Pitch Propeller" in the 1975
> > NFFS
> > > Symposium. It shows a mechanically workable design employing the
> > torsion
> > > spring characteristics of the prop shaft. He had tested it prior
> > to
> > > publication and had found 15-30% better duration over a flaring
> > prop in
> > > low ceilings.
> > >
> > > It took quite a while to lead to better designs of the VP prop.
> > The Brits
> > > tried at the '80 WCh, using essentially the Annis design, but
> > couldn't
> > > get it working well (see Aug. '82 INAV). Jim Richmond introduced
> > his VD
> > > prop in'84 in Chicago and used it at the '84 WCh where he won the
> > contest
> > > with it. After a flurry of activity with VD props, only two fliers
> > were
> > > successful with them - Jim Richmond and Rich Doig. Attention
> > returned to
> > > VPs. Ron Higgs tried one with a spiral spring in '85 and set a Cat
> > I
> > > world record. At this point my collection of INAV is a bit thin. In
> > Dec
> > > '90 Bob Randolph set a Cat I record with a VP prop that looks much
> > like
> > > the classic Banks/Brown design. The prop doesn't use a preload
> > adjust
> > > screw, just a high limit screw (May '91 INAV). I don't know who
> > was
> > > first. I thought it was Cezar Banks who finally developed a
> > compact wound
> > > torsion spring design. Steve Brown made the technology accessible
> > with
> > > his excellent article on how to build a VP in the Oct '96 issue of
> > INAV.
> > > The current VP designs are only small variants of this design."
> > >
> > >
> > > On Thu, 19 Jan 2012 19:48:03 -0000 "Yuan Kang Lee" <ykleetx_at_>
> > > writes:
> > > > Nice to see more F1D's flying. May I ask who were the F1D
> > fliers?
> > > >
> > > > -Kang
> > > >
> > > > --- In Indoor_Construction_at_yahoogroups.com, "icefishdiced"
> > > > <icefishdiced_at_> wrote:
> > > > >
> > > > > Here are the videos I took in December
> > > > >
> > > > > http://www.youtube.com/watch?v=NssKBs1d8rY
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > > ------------------------------------
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > > LeRoy Cordes YOLO
> > > Chicago, Illinois
> > > AMA 16974
> > > In God We Trust
> > > ____________________________________________________________
> > > 53 Year Old Mom Looks 33
> > > The Stunning Results of Her Wrinkle Trick Has Botox Doctors
> > Worried
> > > http://thirdpartyoffers.juno.com/TGL3141/4f216bbb85146198b6m03vuc
> > >
> >
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
>
>
> LeRoy Cordes YOLO
> Chicago, Illinois
> AMA 16974
> In God We Trust
> ____________________________________________________________
> 53 Year Old Mom Looks 33
> The Stunning Results of Her Wrinkle Trick Has Botox Doctors Worried
> http://thirdpartyoffers.juno.com/TGL3141/4f24150baffac1d34fm03vuc
>
Received on Sun Jan 29 2012 - 14:19:34 CET