REFLECTOR:Re: RG vs. Fixed

Chuck Jensen reflector@tvbf.org
Sat, 7 Jun 2003 11:39:41 -0400


I recently bought a Velocity XL RG that was built without transverse bulk
heads. Since the plane was sold as a (0) defect plane, I quizzed the
owner/seller and he, in turn quizzed the Frenchman about the absence.  I did
not fly the plane for two days (over a weekend) until I could talk to the
factory, which I visited with the plane on the following Tuesday.  The
Factory's position, if I may paraphrase, is they are very important, but not
critical for a particular flight.  They advised that the bulkhead be
installed at the very first opportunity.

The Frenchman told the fellow that sold the plane to me that he had built,
and was building an additional two or three RGs, in which no transverse were
installed and that there had been no problems.  I'm am not a structural
engineer (though I stayed at the Holiday Inn last night) but the purpose,
and need, for the transverse bulkhead seems somewhat evident.  

The most obvious event for stressing this area is in event of a hard landing
with simultaneous application brake (say, for sake of discussion, a
correcting rudder on a narrow runway with a gusting crosswind), imparting
maximum torsional force on the gear anchor point.  (Given my piloting
skills, that's not an impossible sequence of events.)

Are the transverse bulkheads necessary?  I guess one never knows until it's
too late, but if you take a look at the retract gear structure and think
about that front bushing floating out there without support, it's not a
comforting vision.  The original design calls for bulkheads to be installed
with three layers of triax; a bit of design overkill if they were only
cosmetic.

In the Frenchman's defense, he indicated the absence of the bulkheads was
not an oversight and was intentional, though he offered to install the
transverse bulkheads at no cost.  Clearly a generous offer, though I'm
concerned since, having left a two phone message and two emails, I've still
not received any response.

Suffice to say, I'm going to install them, however I have to get it done.

Chuck
N27GV, XL RG 300

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Greg Poole
Sent: Saturday, June 07, 2003 4:32 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Re: RG vs. Fixed


I have flush mounted my windows on the same model Velocity (but cannot build
as quickly as Jack obviously has).While routing the lip on the plexiglass
windows was nerve racking (the router continually wants to write it's name
on the rest of the window!), the operation was no big deal and readily easy
to achieve a good result.

In fact, I am likely to have to do  it again if the dark tint glass I
somehow managed to order (I think?)  is too dark for night VFR use.

If this results in the same performance (190kts!!!!!! wow!!!) that Jack
indicates (it was in the back of my mind that this might optimise passage
thru the air) then I am mighty glad I have done it - what is the point of
owning a high performance bird and then tripping it (the bird and the air
flow) up? Jack .....keep passing on the detailed tips - I'll willingly
follow your lead including the flanged front gear doors if I can get 190kts
(looking seriously at 350HP peak power on a turbo'd 13B Mazda).

Did someone say that our French mate isn't installing transverse bulk
heads?????? I'd like to know the reasoning.....

Greg Down Under
Greg Poole
STD RG E
----- Original Message ----- 
From: "jack davis" <n767sd@hotmail.com>
To: <reflector@tvbf.org>
Sent: Saturday, June 07, 2003 1:06 PM
Subject: Re: REFLECTOR:Re: RG vs. Fixed


> 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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> >
> >
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