From: bs464@cleveland.Freenet.Edu (Duncan R. McCoy)
Newsgroups: rec.models.rc
Subject: Re: K&B Help Wanted! (Was Re: Radio Selection)
Date: 17 Nov 1992 23:16:42 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: bs464@cleveland.Freenet.Edu (Duncan R. McCoy)
NNTP-Posting-Host: hela.ins.cwru.edu


In a previous article, ed@kronos.com (Ed Baker) says:

>In article <10328@tetons.idaho.amdahl.com> rbs@sawtooth.idaho.amdahl.com (Bob Smith) writes:
>>In article <1992Nov13.230049.26052@aio.jsc.nasa.gov>, colangel@norm.JSC.NASA.GOV (Michael Colangelo/MDSSC) writes:
>>> 
>>> P.S.  What kind of motor are you using?  Personally, I like the O.S. brand - you
>>> pay a little more - but they are worth it!!  I'd recommend against buying K&B
>>> motors - they suck!  K&B motors always seemed to quit on me at the worst time,
>>> OS motors run like a top.
>>
>>Oh, I wouldn't say they suck!  Inferior, yes, but suck??? :-)  I've owned both,
>>and yes, the OS is definitely a better engine, but for about half the price you
>>can get a K&B BB engine that runs quite adequately.  For comparison, my K&B .40
>>BB turns about 12,000 RPM while my OS .40 SR turns around 13K with the same
>>fuel and prop.  I've had about the same amount of trouble with both of them
>>stopping in the air, and usually this is the result of not having them correctly
>>adjusted.  The OS is a little more forgiving in this regard, but properly
>>adjusted the K&B runs just fine.  The OS is also smoother running, but for a 
>>modeler on a budget I really see nothing wrong with a K&B BB motor.
>
>I've seen the K&B threads before, but I had never encountered an actual
>K&B engine until last week at the flying field.  A new student (1st time)
>showed up with a nice Royal 40-T ARF trainer plane w/ KB 40.  I/We told him
>that we wouldinstruct himm.
>
>I spent most of the day having him start the engine, and taxi the plane to
>the far end of the runway.  I would slowly increase the throttle, and the
>engine would die.
>
>I could not get his engine to run right; it would die on the runway every
>time.  I finally adapted to the engine characteristics, and we had a great
>1st flight!  I had to overcome my insistence that the engine both idle and
>run at full speed, with a transition between the two.  A couple of times I
>let the engine idle for over a minute, and then pushed the trottle up one
>clock only to have it die.  I took that plane out to the far end of the
>runway at least 5 times, only to have the engine die there.  Very amusing
>to my co-fliers :-).
>
>The engine was very consistent; it died every time.  So, to keep it going,
>one had to keep it at very high idle.  It flew just fine, then!
>
>My question is: How do I set this engine so that it both idles and
>                transitions to full throttle without quitting?
>
>>(Now the Sportsters, that's a different matter!).
>
>Maybe this engine is one of these.
>
>>They're also made in the USA, for those of you so inclined

K&B engines are a good deal for the modeler who is a little short
on cash. There are a few things about them that are a little
different than the run "right out of the box" quality of OS and
maybe Magnum.

K&B's need locktite on all screws and need to be broken in very
carefully. You should not use synthetic only fuels. I use a
castor/synthetic blend (Byron Premium Sport Fuel) and it works
very well.

The comment on the K&B .40 running, then quitting could be the
result of two things: (1) tight, new engine overheating and
dying or (2) air leak caused by loose engine screws. The .40
is a ringed engine and not at all tolerant of lean runs. You
can ruin any ringed engine quickly by running too lean. You
want to adjust the main needle so the engine is about 2-4
clicks rich from peak. While breaking the engine in, run about
1/4 turn rich from peak on the bench for about an hour, varying
the rpm's until the engine is loose enough to hold full
tthrottle and the idle settles down. Then put it on the airplane
and run the engine rich until it fully loosens up. This might take
several weeks. If you do it right, the K&B .40 will last for
years. It should swing a 10 X 6 prop at about 12,500 or 13,000.

K&B Sportster engines are, if anything, more needful of proper
breakin than the .40 and .61. They run on plain metal - no bearings,
no sleeves on the crankshaft. They rely on proper fit, careful
run in, and lube. Follow the mfr's recommendations religiously
on breakin. I have a K&B .20 that is four years old and it runs
like new. The sportsters have a lifetime warranty- if something
breaks (not from a crash, though), send the engine back and it
will be repaired or replaced for the cost of shipping. Honest!
  
I also use OS engines and like them a lot. But have found K&B
engines to be reliable, durable and inexpensive.

Duncan R. McCoy
Boulder City, NV

-- 
Duncan R. McCoy
Boulder City, NV
bs464@cleveland.freenet.edu
---------------------------
Newsgroups: rec.models.rc