Conference vmszoo::rc

    see 1193.8 - Found by the (out of date) keyword directory...
    

    There are electronic ways of doing it, however I would recommend
    using electric motors if at all possible.  The motors are then
    automatically in synch and the chance of an engine outage is almost
    nil.  2-4 engine airplanes while rare at most glo fields have become
    very common at elctric meets.  The simplicity of the installation and
    reliability of the motors gives your multi-engine project a much better
    chance of success.
    
    I know little about glo multis except from observing an excessive
    amount of fussing around and a very poor survival rate often due to
    one engine quitting.  Absolute synchronization of the engines seems
    less important than keeping them all running.
    
    Good luck - I hope to do a multi some day myself, they are really cool!

    Thanks for your replies.
    
    Re. -1: Electric engines are most probably easier to synchronize etc...
    
    This is probably the best thing to do (if only one could add some sort
    of loudspeaker to reproduce the unique sound of 4 glow engines running
    together...)
    
    naief

    Pilot at our field has P-38. Getting the engines in sync is not an
    issue. Getting them to run togather at the same RPM is were he puts all
    his effort. Once he can match the RPM's he is all set to fly. It really
    isn't that difficult with good quality engines. He is using 2 Satio
    150's.
    
    Dennis

    Several companies including Jomar sell throttle synchronizers that
    use speed sensors to keep all engines running at the same speed. 
    Multi-engines are a challange and it takes care to get them all running
    properly.  You lose that challange with electric - not to mention
    having to carry all of that heavy "fuel". :-)  I like the sound of
    multis but I'm not turned on by the challange.  You have to be very
    careful of the props when starting.  It's all to easy to get bit by one
    of the running engines while starting or adjusting another.
    
    Charlie
    

    I found that getting each engine set up independently was the key
    to getting the  twin to run well. Once I got the engine running
    properly, I'd kill it and work on the other one. Then I'd start them
    both and use the knob to sync the RPMs by ear on the high end. The  two
    engines might not be the exact same condition and one might be a few
    hundred RPMs stronger than the other. What you don't want to do is tune
    them with the needle valve. You want to sync them with the throttle
    travel. A computer radio makes that pretty simple and you can get a
    nice transition from sync'd idle to sync'd top end. The key is tuning
    each engine properly alone and then using the throttles to balance
    them. Since I went to this method, I haven't been plagued with engine
    outs. I'm going to a pair of OS .32ABC now so I can get lower idles
    since the airbleed carbs I'm using now are tempermental so I have to
    keep the idle high so the plane doesn't want to slow down enough to
    land.

    JIM,
       You would like this P-38. I haven't seen it fly yet but did help
    with the test of the engines and taxi down the runway. He is using 2
    Satio 150's 4 strokes inverted. Sounds reallllllll nice. The mufflers
    are Davis type and with both engines opened up the noise isn't bad.
    Haven't done a db test but it sounds great. Its a bit unique due to the
    muffler system. It was custom made so it fits in the cowl.
    
    Dennis
    

Yellow has one with a pair of G-38s I keep hearing about. I'd love to see one of
these monsters fly. I'm going to amuse myself with a .20 size for the time being.

Jim

    Thats were this guy started. He took a standard 40 size ARF trainer and
    converted it to a twin. He used 2 OS .25's mounted under the wings.
    Flys great.
    
    Dennis
     
    

>Yellow has one with a pair of G-38s I keep hearing about. I'd love to see one of
>these monsters fly. I'm going to amuse myself with a .20 size for the time being.
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Yeah, Jim, Sure, Jim. And how long have we been working on this project now???

Lotsa 8^)       

    Dan, I didn't say I was actually going to build and/or fly it... just
    amuse myself with it. Looks like I'll amuse you as well 8^)
    
    (the date on the plan tube postage is 10/90 )^8

     Why not put a single engine with flywheel and fan in the middle of
    the airplane body with linkage to each prop. I've been thinking about
    designing one like that for some time.
    
     Jacques
    

    Kress Jets in Long Island, NY has a unit that does exactly that.  Its
    mostly intended for electrics, but the idea is simplicity in getting
    both props to run at the same speed.
    
    -Joe