[NSRCA-discussion] Ideas?

[Tom Simes]

On Fri, 14 Jul 2006 10:36:47 -0500
Ron Van Putte <vanputte at cox.net> wrote:
   
> HELP!  We leave for the Nats tomorrow.
> 
> BTW, I have been using an OS 1.40 RX in my airplane for the past two  
> seasons and have loved it.

Hi Ron,

You guys have been doing this long enough that you can fix almost
anything, so I won't presume to give you technical advice. 
However, you're short on time so you need to try and be as efficient as
possible in your troubleshooting process.

Rather than attacking this one component or subsystem (leaf) at a time,
start with the whole system (trunk) and divide it into the largest
possible groups you can eliminate at one time.  This also allows you
and John to divide the work/troubleshooting at each branch point.

Start off by dividing the engine from the airframe - do you still have
an engine that is quitting without the glow driver (like the one John
pulled)?  If so, get it on a test stand with known good fuel and see
whether the problem exists external of the airframe.  

Going down the engine branch of the tree, you mentioned changing
glow plugs fixing the problem temporarily so that's a natural branch
point.  Try taking one of the "bad" plugs and running it in another
engine to see if the problem is really the plug itself or is it just a
symptom of something else being out of spec. (after inspecting it for
contamination and obvious damage of course).

>From here you can keep branching until you isolate what the problem
subsystem is.  Good luck!

P.S.  In one of my smaller OS engines, having to diddle with a
previously good idle mixture setting is one sign that it's time for new
bearings.  If it were me and the "bad" plug ran fine in a different
engine, my next branch point in the engine path would be warming up the
oven and getting another set of bearings installed (as Jim mentioned).

Tom
 
======================================================================
   "Z-80 system stack overflow.  Shut 'er down Scotty, the system's
         sucking mud" - Error message on TRS 80 Model-16B

Tom Simes                                       simestd at netexpress.com 
======================================================================