REFLECTOR: Balanced Injectors

[Richard Riley]

Someone out there is selling the same kind of 
website to aviation businesses - look at Barret 
Performance Aircraft - http://www.bpaengines.com/  Incredibly irritating.

I've done business with Airflow Performance for 
about 12 years.  Superior service, wonderful 
products, terrific prices.  Add any superlatives 
you might think of, they're all accurate.

At 08:08 AM 8/15/05, you wrote:
>Scott,
>
>I had the same impression.  The only reason I 
>stuck with it was Ronnie's and a couple other's 
>recommendation.  Some website designer forgot 
>that 'flash and dash' is okay from an artistic 
>perspective, but we want information, not cutesy graphics.
>
>So, don't be misled by the marginal website.  In 
>the end, you want someone that to do injector 
>balancing, not website design for you.  I'd 
>suggest giving a call..that'll be much more satisfactory.
>
>Chuck
>
>Scott Derrick...
>
>Airflow's web site was certainly a dissapointment.  All that flash and
>glitz takes so much time to load and play you never get to the info your
>looking for.  They should take a lesson from Google,   keep it simple
>and blazingly fast and people keep coming back for more.
>
>Never could find the information about there balanced injector system..
>Gave up.
>
>Scott
>
>Scott Derrick wrote:
>
> > Chuck,
> >
> > Great story and kudo's for Airflow. I was planning on doing the GAMI
> > thing on my TSIO520 once its flying. I thought GAMI was the only game
> > in town.
> >
> > I will give serious consideration to Airflow...
> >
> > thanks again,
> >
> > Scott
> >
> > Chuck Jensen wrote:
> >
> >> A few weeks ago, I posted a request for a recommendation on getting
> >> injectors in an IO-540 balanced. I related that I had done the GAMI
> >> routine, but after a year, the lowest spread achieved was 1.5 gph.
> >> One of the best, if still not great, settings after multiple GAMI
> >> injectors change outs was to run #3 and #6 LOP and the other four
> >> ROP. Not ideal but it kind of worked. When pressed about why the
> >> tuned injectors weren't tuned after innumerable lean test runs and
> >> injector change outs, GAMI said "huh, that's odd" but never solved
> >> the problem.
> >>
> >> Following the suggestion of Ronnie and a couple others, I contacted
> >> Air Flow Performance in Spartanburg, SC. After a couple missed
> >> appointments due to schedule and weather, we hooked up on Saturday
> >> (yes, they volunteered to come in on Saturday to accommodate my
> >> schedule). From the baseline flight of 1.5 gph spread, the next set
> >> of restrictors dropped it to 1.2, then 0.8, then less than 0.4--done!
> >>
> >> In 4-5 hours, I'd resolved the issue that I'd been piddling with for
> >> over a year. Now, in all fairness to GAMI, they were very patient and
> >> persistent. Over the year, they sent a LOT of injectors. Of course,
> >> each required cowl removal, injector change out, then a new set of
> >> lean tests, just to find out they really didn't change anything.
> >>
> >> After the second flight at Airflow, a 5 minute explanation finally
> >> made sense of why the GAMI injector change outs never changed
> >> anything. It turns out the Flow Divider opening pressure is around
> >> 1.5 PSI. Since our test points were around 12 GPH that resulted in a
> >> nozzle back pressure of around 1.7 PSI. What was happening was that
> >> even though a larger nozzle was being installed in cylinder #6 the
> >> Flow Divider was influencing the division of flow to the nozzles. The
> >> solution was counter intuitive, but eminently sensible when
> >> understood. To make #6 rich, the other cylinders were 'cinched down'
> >> with smaller restrictors, which caused the nozzle back pressure to
> >> increase driving the Flow Divider more open so that it would not
> >> influence the division of flow to the nozzles. With more fuel being
> >> pushed to #6 and they dialed right in.
> >>
> >> Now, I assume GAMI is probably that smart also, but the advantages of
> >> hands-on problem analysis and immediate retesting are inestimable,
> >> something that GAMI, due to geography couldn't do.
> >>
> >> More important than the 0.5-0.8 gph fuel savings was the smoothness
> >> factor. The canard, which is an excellent tell-tale for vibration,
> >> was dead calm throughout the ROP area and displayed only a small
> >> vibration when I went into the LOP region. That small vibration
> >> vibration is still less than anything I'd achieved with the GAMI
> >> injectors in either ROP/LOP operations.
> >>
> >> Finally, I note there is a difference between GAMI and Airflow for
> >> making injector adjustments. GAMI changes out the whole injector
> >> whereas Airflow uses an injector body, then they just swaps out the
> >> restrictor inserts, which only requires removal of the fuel line nut,
> >> relatively easy to do even when we have to work around/through the
> >> Velo plenum. With the GAMIs, I was never enthused about screwing
> >> multiple injectors into the cylinders. The odds of cross-threading
> >> and screwing up the injector or cylinder is low, but still there.
> >>
> >> Whether you bring the plane to Spartanburg (SPA) or do it remotely,
> >> I'm guessing you'll come away smarter and with as good or better
> >> results than from some of their competitors. The office walls are
> >> plastered with all the show pilots they tune, including Patti
> >> Wagstaff, Tucker, et al.
> >>
> >> And the best part; the total cost for the Airflow injector balancing,
> >> including new injectors, was about ½ the cost of the GAMIs...and I
> >> didn't have to do all the work.
> >>
> >> So, as you might guess, I'm sold. Without reservation on cost,
> >> service or results, Airflow gets my vote.
> >>
> >> Chuck
> >>
> >> Disclosure: I don't own or have an interest in Airflow...but I wish I did.
> >>
> >> ------------------------------------------------------------------------
> >>
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