REFLECTOR: Running LOP

Sid Knox sbjknox at earthlink.net
Sun Dec 17 09:14:44 CST 2006


When I modified my injectors, I used one of those small, round file-like 
tools (I don't know the official name) that are used for cleaning the tips 
of an Oxy-Accl torch.
I had not thought of using small drill bits ( I have a bunch of small 
carbide printed circuit board drills) but it sounds like they will do a good 
job also.
The first injector I opened-up, being cautious and not wanting to take out 
too much, I took a few light strokes and collected the tiny filings on a 
piece of paper so that I could see how much brass I was removing and how 
aggrssively I could safely wield the "file".  Then, make a flow measurement 
on the flow-bench.  Repeat until I had the flow that I had calculated I 
needed for that particular injector.  Then, re-assemble, fly, take data, and 
repeat as required for all three injectors.  Three, because one of the four 
will be the "reference" injector.... the one that is running the richest and 
therefore need not have its orfice enlarged ... unless I screw-up and go too 
far with one of the others.  Then it becomes the reference and the other 
three have to be re-done.  Fortunately, I did not have that happen.

Not a difficult process but quite  tedious ... especially the removal and 
replacement of the cowling... but well worth the effort to be able to run 
cool and clean and *economical*...  at 50 or 60 deg F  LOP.

Sid Knox
Oklahoma

Velocity  173 RG  N199RS
Starduster  N666SK
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----- Original Message ----- 
From: "Dave Philipsen" <velocity at davebiz.com>
> I've had my injectors out and I experimented with some miniature drill
> bits just to see how they fit without actually drilling the orifice.  In
> doing so, I did find out that some of the injectors fit the drill bit
> snugly as I slid it in and others had notably more "play" indicating
> that they weren't all *exactly* the same size.  I would imagine the
> difference was less than .001 inch though.
 



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