Conference vmszoo::rc

    Jeff,
    
    As long as it can be made to fit (physically), my belief has always
    been that there is "no such thing" as TOO much power!...as I've
    said frequently, you can ALWAYS throttle back.
    
    Installing .60's in .40 size ships is fairly common practice out
    here in the "pucker-brush."  Middle/Sweet-Stiks, many of the E-Z
    variety of ARF's, etc. are frequently seen with .60 engines aboard.
    As a rule, we're talking about mild/friendly handling, non-schneurle
    type .60's (like yer' K&B) which produce the most noticeable diff-
    erence NOT so much is speed as in vertical performance.
    
    The only thing to consider in the building/engine-installation phase
    is proper CG.  If possible, moving the firewall (engine) back 3/4"
    or so will assist in attaining the correct CG without having to
    add a lot of ballast in the tail.  Other than that, just eyeball
    the structure, i.e. wing center-section, firewall, landing-gear
    mount, etc. to assure it will handle the extra load/weight.  Most
    of the mod's I've seen required NO extra beefing-up whatever.
    
    Adios,	 Al

    Thanks Al,
    
    Any other experiences???
    
    Cheers,
    jeff
    

    Jeff,
    
    Well, yes...now that you asked.  Back a few years when the Webra
    .90 was brand new, Bob Freay and Kent Walters both bought one for
    their scale ships but neither of them had anything flyable to break
    the engines in on.  I volunteered my (then) 13-year old Jensen Ugly-
    Stik, then powered by a Webra Black-head .61.
    
    We simply hung the brute .90 on the nose and made no other changes/ad-
    justments except to lengthen the throttle linkage...no tail-weight,
    no nuthin'!
    
    Believe it or don't, the straight and level speed wasn't significantly
    faster than with the .60 but, pull the nose up and WOW!!!  That
    crazy thing would go straight up as far as you couls see to keep
    it climbing vertically...literally out-of-sight! Both engines were
    sucessfully broken-in in this manner and Kent's is still in his
    SBD-3 Dauntless to this day.  Bob's finally shelled-out at last
    years Masters after "many hundreds" of flights over 9-year's service.
    
    The only special consideration I had to make was prop clearance...I
    had to take off from a 3-point attitude (and land the same way)
    to avoid getting the 14" prop in the dirt.  I forgot to mention
    to you that this is another physical consideration you'll want to
    check in yer' application...if it's close, larger wheels will likely
    take care of things.
    
    
    

You will always know when you have too much powwwwwwer.

YOU OPEN THE THROTTLE; THE ENGINE STAYS STILL AND THE MODEL ROTATES AROUND THE
PROP. 

As already stated weight and physical size are the only limitation on engines. 
Too little power will break more models than too much.

John

    
    If the engine were way oversized you might have trouble with low
    speed performance (high wing loading), but a .61 on a .40-sized
    plane isn't way over.
    	One thing you might want to consider though -  is it an
    old engine?  If you ever need to replace it are you willing to buy
    another one the same size (since the plane will be built for it)?
    
    Bill
    

    One definite consideration to overpowering is the control surface
    design.  I have one Ugly Stik powered with an OS 61 FSR ABC.  At
    full power the speed builds up until ailerons leave the wings. 
    Luckily, only one rips off at a time.  I do what I would consider
    an excellent job of applying control surfaces but they are note
    designed to fly at such speed.  1/2 power works just fine.
    
    Regards,
    NCMWVX::VOSS

    Just walked back into the office after standing in the parking lot
    and watching six F/A-18's called the Blue Angels practice for the 
    Pennsylvania International Air Show here this weekend...
                                  
    I concluded:
                  
    There is NO SUCH THING as too much power !!!

    I too am building a SS40.  One problem you will have is building
    the engine into the nose.  If you have already done the nose, a
    larger engine will require you to do some mods to get it to fit.
    I had this problem with my SS20 that I am currently flying.  I built
    it for a 25FP and then decided to try to put in a 25FSR.  I gave
    up when I realized I would have to lengthen the nose almost 3/8
    of an inch to get the longer (Ball Bearing) engine in there.  I
    am now flying with the 25FP.  I am putting a 45FSR in my SS40.
    The other consideration you will have if you put a 60 size engine
    in is the fuel tank size.  You will need at least 12 oz and really
    a 16 oz tank would be better.  Good luck fitting that in a SS40
    with adequate vibration isolation of the tank.  Anything over 8
    or 10 oz will be a tight fit in this bird.
    

    
       In keeping with the tradition of previous planes such as the OS .91
    powered Ace 4-40, an OS .32 powered "mini" gremlin, a Magum .45 powered
    Gremlin, and (2) Twin Gremlins powered by .40FPs, the latest concoction
    from the Nashua "Skunkworks" is almost ready to emerge, a Conquest VI
    ( .60 sized pattern ship) retro-fitted with a YS 1.20SC.  
       The airplane had previously been retrofitted with a YS.91, but as
     of late, the .91 just hadn't had the muscle needed. This gave me a
    few options:
    
        1. Fix the .91
        2. Replace it with a new .91
        3. Upgrade to an engine way to big for the plane
    
       Option 3 was the obvious choice and by far the most fun and
       expensive! :)
    
    
         The retrofit has involved pulling out the elevator linkage and
       retrofitting it with a dual servo setup postioned close to the
       tail of the airplane ( to help balance the monster up front ). In 
       addition I needed to use a BIG shoehorn and a lot of vasoline to get 
       the 1.20 in place! :) Since I am using a 14/14 prop, ground clearance
       is still adaquate and did't require any lenthening of the retracts.
    
          Still a lot of work left, but the goalis to have it ready to
       fly at CMRCM on Sunday after the pattern contest.
                                                             

    I can't wait for this!
    

    
     I think this is a two grunter!!

    Wow - all that mass being braked with a 14/14? 
    How the heck are you gonna land this beast at CMRCM - pop a drogue
    chute or drop an anchor?
    
    I only wish I wasn't heading to the Cape - I'd like to see this as
    well!
    
    A more serious question: do you have the 120 soft mounted - and if so,
    what'd you use?

Dan, with that power-to-weight ratio, why not just leave the landing gear off, 
and hand launch it!!??!  8^]   

You could just hold the nose up and let go ...  simpler even than a Gremlin!!

Landings might be a bit dicey, but the prescribed method would be to kill 
power on final and bellywhap it dead-stick like a Gremlin.

Go for it.  Wish I could see this one.

Regards,
Joe

                   
    
       Actually, it may be tamer than originally expected. The finished
     weight looks to be 9 pds 7 oz. That is the weight of a light 1.20
     sized pattern ship. It will have solid vertical, but nothing
     outrageous. But, that is what you want when flying pattern. 
        The wing loading will increase, but the only place that will really
     effect me is landing. I will prabably just have to apprach slightly
     hotter. I don't anticipate any major problems landing at Central
     Mass.
    
       The engine is soft-mounted via a modified J-Tec mount/Dave Brown
    glass filled mount. Soft mounted is relative though, it will be
    pretty stiff, just the the .91 was when it was installed in this
    plane. 
    
       Charlie Watt and Ifinished most of the work last evening and
    a Sunday flight definately looks doable if I can get the few remaining
    steps done.  
       

    Something like this HAS to be "cought on tape". 8^) Geez, why don't
    you just drop a 120 in the Shuttle while your at it. See ya Sunday.

    
    
      Yesterday after the CMRCM Pattern contest, we had two maiden flights
    of "high-powered" airplanes. The first was a new .60 sized "jet-type"
    airplane designed by Jack Zimmanck and CHarlie Watt and the second was
    the Conquest 6/1.20 descibed in the previous replies.
    
        The "jet" was designed to use .61 long stroke engines/tuned pipe
    combo. The .61 is being superseded in pattern flying by the big
    4-strokes and there are a lot of them laying around, so Jack ( after
    much encouragment )designed a fast airplane to use them. He had 
    previously designed a .40 sized version which he installed a YS.45/pipe
    in. The .40 sized was hand lauched and landed on its belly and flies
    at 150 mph. The new .60 sized has retracts, but is designed to be 
    just as fast.
        SInce the engine was already broken in, it was just a matter of
    setting it up to run faster ( 14,500 rpm! ).  After as radio check and
    making sure the engine was all set, it was time for a flight.
        The take-off was uneventful, and after a couple of trim clicks,
    it flew like it was on rails ( very fast rails! ). CHarlie did the
    flight ( it was his plane ) and he took it somewhat easy on the
    first flight, but it was clear that it has unlimited vertical and
    is VERY fast. The problem came on landing. He can in hot, hit a bump,
    and the VERY short gear ripped right out of wing, so its back to the
    repair shop and design board. Other than the retracts though, a very
    successful first flight of a new design.
       One interesting note: When the wing was removed, there was some
    charring on the plywood wing hold-down plate on the fuselage. This was
    from "wood to wood" vibration from the bolts being slightly loose while
    the engine was vibrating the fuselage @ 14,500!. I had never seen 
    anything like it! ( I guess the rubbing two sticks together thing does
    work! :)
    
        After the test flight of the "jet", it was time for the Conquest.
    After a couple of tanks worth of engine tweaking by Charlie Watt, it 
    was time for a test flight. It was still running rich but responded 
    well to throttle, so it was time to fly.
        The plane took off fine, only required minor trim, and it was time
    to enjoy the new bird! I was absolutlely delighted with its new
    performance and it flys as well as ever ( Tim Taylor "male grunts"
    could be heard for several yards! :). It isn't a "rocket ship", but
    has solid vertical performance. The engine seems very much at home in
    the plane and doesn't give any hint that its too big. It responded
    perfectly EVERY time when I throttled up and back even after prolonged
    idling. The added bonus was it lands even BETTER now. For some reason,
    this weight, engine, and prop combo makes for a very stable, slow,
    controllable approach and landing. I made (3) full stall "greasers" 
    in the (3) flights I flew (on two, the tail wheel touched first! )   
        The new elevator linkage worked great and literally everything
    worked as planned. The YS was VERY thirsty running at it's current "rich"
    setting and I limited my flights to (5) minutes on a (12) oz tank. Once
    it is leaned out, the fuel usage should go back to acceptable. I could
    even detect decreased fuel consumption after just (3) flights. As
    another added bonus, the 1.20 /pipe combo sounds much better than the 
    .91 did with a muffler setup
       
        I ended up adding at least 12 oz to the plane in the retrofit and
    it flys BETTER than before! How often does that happen! I am very happy
    with the current performance of the YS and things can only get better
    once it gets broken-in and leaned out! Another dozen flights and the
    real fun will begin! :)
    
          Can you sense that I am pleased with the results? :)