Conference vmszoo::rc

    I wonder if Al has really flown a twin?  Probably one of Dan Parson's
    if he has.
    
    Charlie
    
    Good to hear his name bantered about
    

    When I spoke with him on twins he used the "WE" sevral times when
    talking about drawing up the flight rules for twins.
    
    
    BTW I believe that a gyro is a must for a twin. You can set up a host
    of switches to give you right or left rudder in an engine out
    situation, but this is only any good if you know which engine is dead.
    A gyro will apply all the CORRECT rudder it can to correct an engine out 
    yaw.
	
    Seems like a winner to me.
    
    
    E x E.

    Even better is an engine speed control.  Jomar makes one that monitors
    the engines and keeps them matched.  If one quits, the other will
    throttle back unless you override it.  Could save a spin.  I like to
    watch twins but I have no desire to have one.  
    
    Charlie
    
    BTW, A Gyro might help but it won't prevent a spin on engine out.
    

    
  >>  BTW, A Gyro might help but it won't prevent a spin on engine out.
    
     Did I open pandora's box here?.
    
    I do and don't agree with you Charlie.
    
    I Agree - Where a twin has a design that cannot handle an engine-out 
    situation then a gyro will have no affect.
    
    I Dissagree - Where a twin has a design that can fly with an engine
    out. The use of a current gyro here will be a winner. 
    
    The modern gyro, if aplied to a rudder control, would try to apply 
    rudder to correct yaw up to the full throw of the available amount.
    The rudder will be held in, in the correct direction, and will only be
    a problem after touchdown whereupon it will have to be overridden by
    the rudder contol from the pilot or dissengaged.
    
    Planes like DC3's Mosquitos and Hornets will fly like this. Lightnings,
    for example, may not?. 
    
    The plane is slower and draggier in an engine-out-rudder-counter-yaw 
    flight configuation and care will have to be taken not to stall and 
    spin. but the plane will stay flyable and the pilot will not have to
    worry about holding in a bootfull of rudder or which direction to hold
    it!.
     
    I hope I have explained the use of the gyro clearly?.
    
    Regards,
      
    E.
    

    Wouldn't you know it?. I was just reading my K-factor and there in black
    and white was a reference to the fact that David Von linslowe was
    planning to fly an electric at the FAI world championships.
    
    There were two reasons why he did not fly it. The first was that he
    only just got it ready and the second was that it did not quite have
    the verticals that he needed for FAI world class competition.
    
    Bearing in mind that he flys a wicked powefull 120 on the front of his
    regular, Nats winning, ship I imagine that he had almost cracked the
    code on pattern electrics.
    
    I also read that one plane did fly with volts instead of methanol.
    
    As soon as there is affordable, equivalent or better power, longevity
    etc. from an electric pattern plane I will try it.
    
    
    Regards, 
    
    EVL-1.
    

If you go back in the P-38 topic that I started years ago while Al was 
still in here, you'll find that he did fly a Royal P-38. You'll also 
find out how he came to own it in 1002.3 (found through the directories 
in 11.* and the P-38 keyword 8^)

Al also talks about rudder gyros in scale (he was against them) in 
the scale and P-38 topics.

    OK, I got a comment about loss of an engine on a twin. Get ready, this
    is a "he doesn't know what he's talking about so he thinks it's easy"
    comment.
    
    I haven't flown a twin, but it seems to me that if an engine flames
    out, all you need to do is throttle back to reduce the yaw force and 
    land it as if it was dead stick. You could even kill the remaining
    engine to force a true dead stick landing. And we all have experience
    landing without power, so that isn't major trauma. If you can't make
    the field, couldn't you apply just a little power, holding in
    compensating rudder (just like a slip landing), and nurse it back to
    the field? There must be some important factor I'm not considering.
    
    OK, rip into me...
    
    Dave
    

You're always flying "engine out" 8^)

From my experience flying the GremTwin (to practice just this kind of 
thing before building my P-38) I can say that light travels faster than
sound. I will see the twin spinning before I hear the engine get sick 
(if the plane is away from me). The rudder compensation of a gyro might 
give me enough time to throttle back. One flight at Quinopoxit last fall
I did land single engine because I heard the engine in trouble and 
throttled back in time. That was also before I added the outthrust on 
the pods (3 degrees). The other place where I had problems was loosing 
an engine on a "go around". It really is interesting to see a cartwheel 
start BEFORE ground contact!

    Jim is right about "seeing/hearing". Only if you know which engine
    is out can you correct for it.
    
    I researched quite a few model twins when I was designing the F7F and
    found a lot of outthrust in all of the designs. The engine that turned
    the top of the blade into the fuselage had less sidethrust because the 
    torque helps keep the plane level. With the F7F I opted for opposite   
    rotating engines and had them both turning the top of the prop in
    toward the fuselage.
    
    If I ever complete the F7F project it will have a gyro on the rudder. 
    
    Regards,
    
    E.

    I think you're giving the Gyro too much credit!  Throttling back the
    good engine is the only thing that'll save most twins on engine out
    except at full speed where the rudder authority might be enough to keep
    it from getting into a spin.  
    
    I still say a speed control would be very worth while for a big twin.
    
    I doubt that anything would save a Gremtwin in an engine out.
    
    
    On electric pattern ships one advantage is that there are no rules on
    electric power yet so you can do what you can to get maximum
    performance.  A YS120 will look cheap next to a pattern electric system
    though.
    
    Charlie
    

    RE: -5 Pattern Electrics
    
    Keith Shaw on Pattern Electric - "The development of a truly competitve
    electric F3A pattern machine is still a little way off, but most sport
    modelers wouldn't be interested anyway.  However, electric power can
    provide the level of aerobatic performance seen at most club fields."
    
    Keith Shaw on future battery technology - "Many people are waiting
    for the magic, featherweight, high capacity cell to arrive before
    entering electrics.  I believe it will be a LONG way into the future.
    I try to keep abreast of battery technology in the scientific
    literature, and all the hoped-for "saviors" have some pretty severe
    drawbacks."
    
    I agree with Shaw on both points, except that I think a competitive
    electric FAI pattern ship is a long way off.
    
    
    Re: 1573.11 The Cost of an Electric Pattern Ship
    
    The following costs are typical for electric components that would be
    suitable for an electric pattern plane:
    
    Astro Pattern Wind 60 motor -   $200
    28 1400 mah cells @$3.50    -   $98
    Astro 205 Speed Control -       $105
    Astro peak detecting charger -  $113
    Misc connectors/wire -          $10
                                   ********
                                    $526
    
    *Quite a few "European designs" utilize smaller motors running on less
    cells(14-20).  This type of plane would reduce the cost by $100 - $150.
    
    
                                                           Regards,
    
                                                           Jim
    
                 

    The problem with twins is that if you loose an engine, you'll generally
    be in trouble before you know you lost the engine.
    
    Some sort of speed controller that would automatically throttle the
    working engine back if the other dies is probably the best defense
    against going out of control being as how your ONLY defense is to
    chop the working engine.
    
    The NEXT best thing is a gyro that will give opposite rudder if you 
    loose an engine. It might not allow the plane to continue to fly
    straight, but it would give you another second or two to perceive that
    you had lost an engine.
    
    I would imagine that if you all of a sudden saw your plane flying with
    tons of adverse yaw, or yawing off to one side and you can't stop it,
    you would eventually determine that you had lost an engine. At least
    at that point, the plane is still flyable and you can throttle back.

                                        
      Dave,
    
         You are correct, that if you are flying with sufficient speed and
    altitude, you can just throttle back and land. I have been able to
    accomplish this once (out of about 6 engine failures ). Unfortunatly when
    doing low passes, climb outs, touch and go's, etc, you are rarely in
    a good position to have an engine out. I could significantly reduce my
    risk of a crash after an engine failure if I flew the twin 200' high
    the whole flight, but it just ain't no fun! :).
    
        Having flown full scale multi engine planes, I can say it can be
    tough enough to identify the "bad" engine, even when you are sitting in
    the plane, never mind from several hundred feet away!
    
        I agree with Steve, in that the engine sensor would be best, with
    a Gyro coming in a weak second (I'll leave mine in my chopper, thanks!)
    Having both props turning inward to the fuselage would be a big help too!
    
        The one thing I believe that Al Casey has absolutely right is the
    method of he states of getting both engines adjusted independent of
    each other, and let them synch up later. Engines should be synched with
    the throttles, and NOT by changing the mixtures when ever possible.
    The mixes on the 347 make this fairly easy.
                                                    
                                                        DW2

    Here is more of the article on twins by Dan Parsons:
    
                  "Don't kick in Rudder"
    
    "When you lose an engine, don't worry which engine quit.  Believe me,
    you probably won't know which engine you've lost for quite a while, so
    don't even think about kicking in opposite rudder or rudder trim.
    
    In the surprise, excitement, fear and tension following the loss of an
    engine, especially if the plane does an immediate whoop-dee-do, i can
    guarantee you won't know which engine went out, much less which rudder
    and/or rudder trim you think ought to be put in.  And if you kicked
    in the wrong rudder, you may well do your plane in right then and 
    there.(Pilots of full-scale craft have shut down and feathered the good
    engine, and their sitting in the plane!).
    
    There's nothing wrong with turning into the dead engine, as long as you
    keep the turn gentle. In fact turning into the dead engine is the
    natural inclination for your twin.  It may well be easier than 
    turning into the running engine, which will probably require forceful
    use of rudder, which will create more drag and slow you down."

    Airspeed is your savior if you lose an engine.  However, as Dan said,
    you're in trouble if you're going vertical or on takeoff and haven't
    achieved enough airspeed.  Guess when you're most likely to lose an
    engine?  Not when you are flying fast straight and level!  If one's set
    too lean, you will lose it at the worst possible time when you are
    taking off or pulling vertical.
    
    
    Speed control is the way to go.  I wouldn't consider a big scale twin
    without one.
    
    Charlie