REFLECTOR:Re: RG vs. Fixed

jack davis reflector@tvbf.org
Fri, 6 Jun 2003 23:06:51 -0400


Yes, I used the triangular GPS calculations as laid out in a Sport Aviation
article.  I've tried it several times to be sure.  I've also made several
long cross-country flights which continually demonstrate I'm getting the
speed I think I'm getting.  Actually, my airspeed indicator use to read low
compared to my ground speeds, but the factory helped me get the static port
straightend out.

The aircraft I have is a Std-RG Elite with a 200 hp Lycoming LIO-360-C1E6
with oversized cylinders, running an MT prop.  Fuel burn at 8500 feet is
usually around 10.5 gph (I usually run a little on the rich side).

I have often told folks that you can get speed gains if you pay attention to
airflow in the boundary layer (typically, the first few millimeters above
the surface).  Lots of articles have been written about minimizing the
"trips" in the boundary layer.  I think my biggest contributor is the flush
mount windows.  This was painstakenly done by routering a grove in the
window glass so that it would fit flush in the fuselage.

Cheers . . .

Jack
----- Original Message -----
From: "Scott Derrick" <scott@tnstaafl.net>
To: <reflector@tvbf.org>
Sent: Tuesday, June 03, 2003 11:54 PM
Subject: Re: REFLECTOR:Re: RG vs. Fixed


> Jack,
>
> Have you flown a fixed triangle course to get these numbers, as GPS
> ground speed will lie unless you average it over a triangle or square
> course?
>
> Thast a very impressive speed, what kind of Velocity, engine, prop are
> you using and what is your fuel burn at that speed?
>
> Scott
>
> jack davis wrote:
> >>I am not really sure what the speed loss >would be with a good fitting
> >
> > farings.  I >think 10kt could be high.  I have a IO->360 @210hpw/
> > 10-1pistons and mt.  I >true at 178kts balls to the wall above >8K.
What
> > about other' fliers REAL no >B.S. #'s.
> >
> > I can honestly say that I get much higher true airspeeds and the GPS
> > confirms what I'm seeing.  I true to about 187-190 KTAS.  Of course, I
have
> > made modifications including flush mounted windows, flanged main gear
doors
> > and tightly fitting nose gear doors, aileron gap seals, low drag oil
cooler
> > ducting, modified cowling, and tight seams everywhere.  I don't know
what
> > any of these things are worth individually.  I am working on a mod that
will
> > completely enclose and streamline the main gear, but don't know if this
will
> > add any more speed.  I can tell you that I love every knot I gain.
> > Aerodynamic efficiencies are so much better than adding more horsepower.
> > When you are flying long cross-countries, a 30 or 40 minute cut in time
is
> > well appreciated.
> >
> > Jack
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