REFLECTOR: Jeffco or not?

Mon Jan 28 11:11:13 CST 2008

>> BTW, what are the actual reasons for flipping the airplane over?

I believe it makes it easier to do the lay-ups from the top of the spar to
the top strake skin, and from the aft fuel bulkhead to the top strake skin.
Also makes it easier to do the finish work between the fuselage and the
lower strake skin.  But, I wouldn't know.  I never flipped my plane.  :)

Andy

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Grigore Rosu
Sent: 01-28-2008 11:38
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Jeffco or not?

Thank you, I will then go ahead and order the Jeffco.  In the meanwhile I'll
finish trimming the bulkheads and the buffles (what a job!  and I thought
that trimming to fit the panel was a lot of work ...).

I will soon send a link to my airplane webpage (still have to upload tons of
pictures); that will show how I keep the airplane level: I'm not using
bottle jacks, I have some special-made sawhorses that are quite rigid and do
not let the airplane touch the ground at all.  I measure the three angles
everyday before I start working and nothing changed so far in about one
month since I suspended it.

BTW, what are the actual reasons for flipping the airplane over?  It sounds
to me like a very difficult and risky job, which I'd like to avoid by any
means.  It would have been so useful to have a special section in the manual
explaining what to do when the airplane is upside down!

Grigore

On Jan 28, 2008 9:06 AM, Andy Millin <amillin at sbcglobal.net> wrote:

	Hey Grigore,

	Joe is a pretty savvy builder, and I agree with everything he wrote.

	I too bought my Jeffco from the factory.  They now have a slower
hardener
	that will give you better working time.  The color difference from
the EZ-84
	provides great contrast.  Much easier to tell if you have a thin
spot.

	I did flange the tops of the baffles.  Very grateful to Joe for
sending the
	pics and write-up.  I too was able to complete the strakes without
flipping
	the plane.  I also was fortunate enough to have the strakes hold
pressure
	for 24+ hours.  Whew...

	As for the lower strake/removing the wing question:  I spoke with
Rob
	Johnson some time ago.  Many of the "Old Timers" on the list will
remember
	the Ditch Master.  Rob did not have room to put both wings on in his
garage.
	His solution was to roll the fuselage out of the garage, install the
wings,
	install the lower strakes, remove the wings, and roll it back into
the
	garage to complete the strakes.  He did it all in one weekend!

	Much later when he put the wings on, they were misaligned by about
1/2" on
	each side.  His experience said the strakes are not locked-in until
the
	upper skin is bonded on.  I listened to his experience, and did not
remove
	the wing until the strake was completed.

	I know this method worked.  I have had the wings back on a couple
times
	since then and everything still lines up.  The other thing that we
did not
	get into was wing incidence.  If the strakes were no longer aligned
with the
	wing, then one could reason the incidence of the strake, wing, or
both was
	no longer what was desired.  Brendan had written about this in his
"The Sh*t
	that Flies" column.  A Velocity can fly with things really out of
alignment.
	Almost by definition, it will mean drag and a slower airplane.  One
of the
	best drag reduction favors you can do for yourself is to build a
true
	airframe.

	One small tip on the strakes.  Most of us use a bottle jack on some
type of
	stand on the outboard wing to hold the incidence during strake
construction.
	Bottle jacks are not meant to hold the same position indefinitely.
Some
	know this lesson in a painful way.  They WILL slowly bleed down.  I
used
	hose clamps around the ram of the jack to lock it in place.  There
is a
	picture somewhere on my site.  It worked very well.

	I liked Joe's idea of using a balloon.  I used a simple water
manometer.
	Remember, you are looking for a good seal not a precise measurement
while
	you are checking.  If it can hold pressure for 24 hours, you should
be
	good-to-go.

	Andy

	-----Original Message-----
	From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
On

	Behalf Of Joe Ewen
	Sent: 01-28-2008 8:20
	To: Velocity Aircraft Owners and Builders list

	Subject: Re: REFLECTOR: Jeffco or not?

	Grigore,
	1-I believe the Jeffco is considered the preferred approach.  I
bought mine
	from the factory.

	2-I used a balloon to test my tank.  After sealing the fuel cap with
4"
	masking tape, a balloon was connected to the vent line and air blown
into
	the tank's fuel supply line.  A temporary valve in the supply line
was
	closed.  I tested my tanks individually for 24+ hours.  During that
time the
	balloon contracted due to temperature change, but came back to
original
	inflation when the temperature came back up.  In fact one balloon
burst from
	the higher temp the next afternoon.

	3-I completed one strake then worked on the second.  May be personal
	preference, learn on the first and the second is usually constructed
more
	efficiently.  I left the wings on until the strakes were finished.

	I departed from the manual on a couple of techniques.  One was I
used Ronnie
	Brown's procedure for making the baffle templates (I believe he
outlines the
	process on his web site.)  The other departure was to create flanges
on the
	upper portion of the bulkhead and baffles to eliminate the need for
	inverting the fuselage.  I shared this approach with Andy M, if he
used the
	technique maybe he can comment of his success.

	At the time of construction my strakes tested leak free.  I will be
	retesting now that I am close to completion and hope they are still
leak
	free.

	Joe

	       ----- Original Message -----

	       From: Grigore Rosu <mailto:grigore.rosu at gmail.com>
	       To: Velocity Aircraft Owners and Builders list

	<mailto:reflector at tvbf.org>
	       Sent: Monday, January 28, 2008 1:34 AM
	       Subject: REFLECTOR: Jeffco or not?

	       I'm about to install the bulkheads in my first strake and
therefore
	I'll soon need to worry about the fuel tank.

	       1) Should I use Jeffco or not?  The manual sounds as if
Jeffco is
	optional ...  If I should use it, where can I get it from?  (I can
do a
	random search on the internet, but perhaps there are some better
avenues
	that you may have encountered so far).

	       2) Do I need an altimeter to test the fuel tank?  I have
none, but
	the messages I could find in the reflector archive on this subject
mention
	an altimeter.  BTW, can I test each tank in isolation, or they need
to be
	both installed first and checked together?

	       3) Should I finish the first strake (including installing the
upper
	strake) and then move to the other one, or it is better to also
install the
	lower strake on the other side and its bulkheads, then do both tanks
at the
	same time, and then install both upper strakes at the same time?
Note that
	I can only install one wing at a time in my garage.  The flow-chart
that
	came with my manual says that the wing can be removed once the lower
strake

	is installed ... I'm a bit reluctant to do so though, because I'm
afraid the

	torsion generated by the spar may be too big without the upper
strake.

	       Thank you,
	       Grigore

	________________________________

	       _______________________________________________
	       To change your email address, visit
	http://www.tvbf.org/mailman/listinfo/reflector

	       Visit the gallery!  www.tvbf.org/gallery
	       user:pw = tvbf:jamaicangoose
	       Check new archives: www.tvbf.org/pipermail
	       Check old archives:
	http://www.tvbf.org/archives/velocity/maillist.html

	_______________________________________________
	To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector

	Visit the gallery!  www.tvbf.org/gallery
	user:pw = tvbf:jamaicangoose
	Check new archives: www.tvbf.org/pipermail
	Check old archives:
http://www.tvbf.org/archives/velocity/maillist.html