REFLECTOR: Jeffco or not?
Grigore Rosu
grigore.rosu at gmail.com
Mon Jan 28 13:59:12 CST 2008
Hi Andy,
Thank you for your elaborate answer.
Just a clarification regarding your answer:
You said:
"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..."
I saw your pictures on the web and they are nice. However, if not
absolutely necessary, I'd prefer to go with the standard approach to save
time, hoping that my tanks will not leak. Have these flanges had anything
to do with flipping the airplane over? It seems to me that these are two
ortoghonal issues, but better check.
Is it true than that the main reason for flipping the airplan is to more
easilly install the BID layups between the upper strake and the spar? In
theory, I can see some solutions to that part without flipping the airplane;
as usual, the practice will be the decisive part.
Grigore
On Jan 28, 2008 11:11 AM, Andy Millin <amillin at sbcglobal.net> wrote:
> >> 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
>
>
>
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>
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>
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