As regards the Woodcomp (nee Kremen), performance data is shown at:
http://www.sebestair.de/sebnav/frameset_prop.htm
However, the cruise speed of the Europa puts the operating point way off to
the top right of the diagram, well beyond the range of data presented. Of
course, with the eye-of-faith one can project ruthlessly the data, but to
any conclusion you like!
It does perhaps show that the original design was meant for slower aircraft.
However, users of the prop in the UK report good results; don't they Bryan?
Bryan??
Duncan McF.
----- Original Message -----
From: "Fred R. Klein" <fklein@orcasonline.com>
Subject: Re: Europa-List: Arplast info please? Was prop balancing (+ Advert)
<fklein@orcasonline.com>
>
> Brian,
>
> I forward the following info on Arplast props plus some of the info I've
> uncovered in my own prop qwest:
>
> >> - Jerry Davis @ Lyndhurst Touchdown Services, reps for Arplast
Propellers:
>
> >> this unit is being used in several Europas; blade profiles & twist
unknown.
> >> PV50 propellers are designed for use on experimental and similar
aircraft.
> >> They are not certified. There are around 250 propellers fitted to 912,
912S
> >> and 914 engines. We now offer a constant speed controller designed and
> >> manufactured in the UK. Prices are as follows:
> >>
> >> Propeller less controller is 2700 Euros $3500
> >> Paint option 130 Euros $170
> >> Standard controller is 150 Euros $195
> >> Constant Speed controllers is 475 Pounds $880
> >> Optional manifold pressure sensor is 55 Pounds $100
> >>
> >> All plus shipping. Prices in dollars are approximate. For a CS version
with
> >> MAP sensor and black blades price would be around $4480 + shipping.
> >>
> >> Propellers are available in Black, Red, White and Grey. For the non
black
> >> props the backs of the blades are painted matt black with an aerosol.
This
> >> matt black is not very durable so for the paint option extra the back
of the
> >> blade can be painted in a two pack Satin black polyurethane paint which
is
> >> durable. The black blades do not require this option.
> >
> >> best regards Jerry Davis
> >>
> >> Managing Director
> >> Lyndhurst Touchdown Services Ltd
> >> jerry@ban-bi.com
>
> My decision on propellers (as yet undetermined) is being influenced by
some
> info and concern about blade design which I share as follows:
>
> > - THE WARPDRIVE BLADES
> >
> > The WarpDrive blade is a quality product w/ many fine characteristics;
> > however, it suffers in a high-cruise-speed situation. All WarpDrive
blades are
> > from the same mold and blade length is varied by trimming. Consequently,
> > for a given application, it is not possible to optomise and provide the
> > correct amount of blade area, disc area, pitch, pitch distribution etc,
etc.
> > The design was optimised for 72" to 84" prop diameters, engines in the
80-100
> > hp range, flying at 100-125 mph cruise speeds. At full length the blades
have
> > a twist of 20 degrees; when cut down for the 64" dia. Europa
application, the
> > blade twist reduces to 13 degrees.
> >
> > - quote from Glenn Crowder, Europa pilot, Golden, CO
> >
> >> The twist is important on your application because as you approach the
fast
> >> part of the flight envelope, the inboard sections of the prop begin to
go
> >> into beta mode. This means the air is being accelerated over the lower
> >> camber faster than over the upper camber, essentially making reverse
thrust
> >> (or at least making enough drag to be the main factor in acheiving
> >> equilibium - no more acceleration). For airplanes in the 135 mph
> >> range, a proper design might have about 40 - 50 degrees of twist from
the
> >> tip to the most inboard definable sections. A Warp, at 64" has about 13
> >> degrees. So, the lack of twist on the Warp and the resulting drag on
the
> >> inboard stations is certainly slowing you down but there is NO off the
shelf
> >> design out there yet that can well accomodate your plane.
> >
> > - quote from Stuart Gort, President, PowerFin Props
> >
>
> I queried Airmaster in this regard as follows:
> >
> >> Hi Martin,
> >>
> >> As I've proceeded w/ various threads of enquiry as to prop selection
for my
> >> Europa XS mono, I've been given some disappointing comments about the
Warp
> >> Drive blades; namely, that they have insufficient twist which imparts
> >> negative
> >> thrust along the inner portions of the blades when the pitch controller
sets
> >> the coarse pitch for max. efficiency and fuel economy (i.e., min.
propeller
> >> rpm) in the higher speed ranges.
> >>
> >> One Europa flyer/owner claims that this drawback of the Warp Drive
blades was
> >> evident when he switched to a fixed pitch, 3 bladed, 64 x 62 wood prop
and
> >> achieved a 20 mph increase in speed at cruise, other conditions being
equal.
> >> (This example did not involve the Airmaster hub, but rather an NSI hub
w/ WD
> >> blades).
> >>
> >> Do you think this is a fair criticism of the Warp Drive blades?..and,
if so,
> >> was it something you considered and felt you could live with given the
other
> >> excellent characteristics of the WD blades?
> >>
> >> Fred
> >>
> >> - hoping to achieve the Europa-advertised 200 mph!
> >
>
> I received the following response from Airmaster:
>
>
> >> Dear Mr Klein
> >>
> >> The issue of blade design is an interesting one and I am sure you will
find
> >> a variety of opinions on it.
> >>
> >> I do not doubt that the WD design could be improved apon if sufficient
> >> knowledge and money was applied to it. However the performance from
them is
> >> not as bad as you may have been told.
> >>
> >> I know that Europa have always favoured the WD blades even when they
had
> >> many other types to choose from. I would question the ability of a
fixed
> >> pitch prop to gain 20 mph over the Airmaster.
> >>
> >> Tests we conducted with Europa USA using a monowheel 914 with the
Airmaster
> >> compared to a Whirlwind 2 blade. The two blade was designed
specifically to
> >> compete on the Europa and so should be as good as it gets.
> >>
> >> There was no reported difference between the two at sea level up to
5000 ft
> >> (where most of your flying is done) and a few knots at 15000ft due to
the
> >> Whirlwinds comparatively large blades.
> >>
> >> In all other regards the WD have been outstanding in terms of
reliability
> >> and wear.
> >>
> >> We may test other blades in the future but for the present we have been
> >> asked to stick with Warpdrive.
> >>
> >> Regards
> >> Martin Eskildsen
> >> General Manager
> >>
> >> Airmaster Propellers Ltd
>
> Brian...I believe but cannot confirm that the twist in the blade design on
> the Arplast prop is greater than that of the WarpDrive blade.
>
> Fred
> A194
>
> on 3/15/05 12:36 PM, EuropaXSA276@aol.com at EuropaXSA276@aol.com wrote:
>
> >
> > In a message dated 3/15/2005 1:02:25 AM Central Standard Time,
> > combined.merchants@virgin.net writes:
> > I then changed my prop for an Arplast PV50 VP prop and the
> > vibration was much worse, so I had a go at dynamically balancing it by
trial
> > and error by placing washers under the spinner screws and judging
whether
> > Hi William:
> > Where can I find information on this Arplast PV50 VP? I just Googled it
and
> > all that really turns up are Europa related sites. It appears that a
number of
> > Europas may have this baby installed. Is this a 3 blade design?
Electric?
> >
> > Seeking Europa XS performance information when bolted to a 912ULS.
> >
> > Happy trails.
> >
> > Brian Skelly
> > Texas
>
>
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