Conference vmszoo::rc

Jim,

I was in the queue behind a guy trying to get a consistant run out of a ST3000
once because I was on his frequency. I think the definition of "set up properly"
is that it DOESN'T quit so, no, it doesn't happen once set up properly. The real
questyion is how much does it take to get it set up and, once set up is it
stable over time. I think a lot of this is a matter of proper break in. I see
people take engines out of the box and tweak them to the max RPM and then wonder
why they're quitting. The guy with the ST3000 didn't have a clue on what was
causing his problem (turned out to be fuel feed and a tank problem) and was
pretty upset. I've also seen engines that start first or second flip and run
perfect every flight. I don't think it's a classification issue as much as a
familiarity with the engine and being able to diagnose and solve running
problems. Recognizing that an engine is overheating or going lean or loading up
on idle can make a big difference regardless of type or size. I think you can
get either engine type to be reliable. Which do you want to deal with at the
field... methanol or gasoline? I would prefer glow, personally.

    re: -1
    
    Jim,
    
       What you are saying makes sense and is what I basicaly hear - "If
    you know what you're doing they all run O.K."
    
    That being said, not one person in all the inquiring I have done in
    this conference and at the field has recommended an ST25/30/4500 or the
    O.S. BGX-1.
    
    The only guy running an ST3000 at my field is a bumbler who has
    problems with everything, so I can't say if his problems with the
    ST3000 are real or self inflicted.
    
    I have heard rumours of fuel draw problems with the BGX-1.  A guy had
    one for sale new in the box last year at my field for $200.  Why was he
    selling it so cheap?
    
    I would really like to hear at least one person say - "I own an ST3000
    and it's a great running engine."
    
    I have not heard a positive recommendation for any large glo engine
    from anyone.  After the O.S. 1.08 every engine you talk about raises a
    lot of questions.

    
       When I was investigating what sort of engine to buy for an Ultimate
    Kit I have ( estimated completion date, 1 week after Jim Reith finishes
    his P-38 :) The conclusion I reached ( in 1992 ) was that the ST2500
    is a rock solid, well designed engine, the ST3000 really needs an
    ignition to make it reliable, and at the time, the BGX was an unknown
    quantity.
       I did not investigate Gas alternatives due to the weight, and having
    to deal with gas.
       A downside was the cost of the glo fuel, 1 oz a minute(+) with
    the ST3000.
    

    
       I forgot to mention, I was looking at an inverted application for
    the ST3000, and thats why the ignition was recommended.

Jim,
there's lots of big birds flying at my field. With a few exceptions they're all
running gas. The exceptions either run one of the Super Tigers or the BG1.  

I'd think with your tow plane you'd want a strong reliable engine that you 
didn't have have to fuss with. That makes the gas engines a strong candidate 
from my point of view. You can probably get a better power to weigth ratio 
with a glow engine but I don't think a tow plane is the kind of application
where you want to be on the leading edge.

    Re: -1
    
    Dan,
    
       Thanks for the input.  I actually would like to go with a gas engine
    due to the reliability.  There are a couple of problems, the first
    being the weight of the G-38.  My plane needs about 58 oz. up front to
    balance.  The G-38 weighs about 71 oz. without spring starter,
    backplate, and isolation mount.
    
    The next problem is the cost which will probably exceed $400 with the
    above mentioned accessories.
    
    Tonight I will see if the plane would balance with a 75-80 oz. motor by
    moving the 2000mah rx pack as far back as is practical.  The nice light
    tailfeathers I meticulously built are now proving a detriment to gas
    engine operation!
    
    I would very much like to hear your impression of the vibration of a
    G-38.  How does is compare to say a 1.20 2-stroke?
    
    One option I am considering is buying a Super Tiger 3000($209) and if
    it does not prove reliable, I could purchase a Pro-Spark Ignition
    system($189) and not have any more invested than the G-38 would have
    cost.  
    
    In many respects my application does not fit the situations that seem
    to give the glo engines problems.  My plane will have the engine
    totally exposed(no cowl), and no vertical or aerobatics will be done.
    The engine will be run full throttle from takeoff to the release of the
    sailplane and then throttled back to idle until it is landed.  the
    motor will be mounted upright.  I wil run it quite rich as absolute
    peak rpm is not necessary for my application.  So maybe the S.T. would
    work fine operated in this manner.

    Jim,
    
    I've got a new, never run OS BGX with an ignition system that I will
    make you a deal on if your interested.  Since this is my last day a DEC
    call me at 319 373 5433 if your interested.
    
    Will

    Well I just ordered an ST3000 for my new towplane.  Both Tower and OMNI
    had the engines on backorder.  INDY had 2 left at $209, so I got it
    from them.
    
    I decided on ST3000 for a couple of reasons - price and hopefully parts
    availabilty.  If money was not an issue I would have gone with the Moki
    1.8, but the ST is at least $100 cheaper.
    
    I hope this engines runs as well as my O.S. 1.08.  As usual I will
    report how things go.
    

    I have bench run the ST3000.  With about 1 gal. of fuel through it, it
    is spinning a 20x6 Zinger at 6800 RPM(needle is set very rich).  I
    figure it will get into the low 7000 RPM range when it is fully broken
    in and I lean it out some.  I am using a J-tech Snuffler muffler.
    
    I had considerable difficulty getting the engine to run well.  The
    problem turned out to be the fuel.  The motor would not run reliably on
    standard Red Max fuel(10% nitro).  Switching to Red Max Super Tigre
    fuel(10% oil) completely cured the problem.
    
    The carburetor has proved a bit fussy compared to the O.S. 1.08.  The
    engine does start very easily by hand, but likes to run backwards.  It
    appears the ST3000 is about 15% weaker than the Moki 1.8 and about
    equal to the Zenoah G-38.   Vibration level is quite low!
    
    If I can get the ST3000 to run near 7500 RPM with the 20x6 Zinger, I
    will be very happy with the engine.
    
    I will post static thrust within the next two weeks.

    An update on the ST3000.  The best performance I was able to obtain was
    7000 RPM with either a 20x6 Zinger or an 18x8 Zinger.  The static
    thrust was around 14 lbs(no better than the O.S. 1.08).
    
    The towplane now has a new O.S. BGX-1 on it.  I will report the thrust
    and how the motor handles(starting, idling, reliability, etc).

    I ran the BGX-1 last night straight out of the box.  It hand started
    on the 2nd flip.  I ran three 24 oz. tanks of fuel through it.  IT
    STARTS, RUNS, and IDLES FLAWLESSLY!  Best reading was 7400 RPM with a
    20x6 Zinger.
    
    I was warned and had to learn the hard way.  Again I heartily recommend
    O.S. engines.  The three 1.08's and now the BGX-1 I have seen, run
    wonderfully without any hassle.
    
    It's ashame thst the other manufacturers can't get it right, it
    certainly makes the hobby a lot more tedious.

    We towed all weekend with the BGX-1.  It ran flawlessly, no deadsticks,
    and idles ridiculously low.  It does a much better job of pulling up
    the 1/4 scale gliders.  We are using a 22x8 Zinger and getting 19 lbs
    of static thrust. Vibration is also quite low.
    
    This is an excellent motor and only $50 more than the ST3000.