REFLECTOR: Jeffco or not?

Grigore Rosu grigore.rosu at gmail.com
Mon Jan 28 10:38:20 CST 2008


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
>
>
>
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