Fly 1/2 A, then you could get back to having engine problems!    

Thanks for the help Larry, times like this you find out who your friends are.   Larry didn't you say the lap speeds were around 4.5 seconds?  I am not sure about the offset, the engine appears to be pointed stright ahead but it is not centered on the firewall.  The template they give for the ST 51 intentionally mounts it off center this may produce the same effect as engine off set.  I agree it must be line rake and I will continue to play with it but I just may take up 1/2A, heaven forbid!
Andy

Andrew, I don't know what prop you are using, but I'd suggest more diameter and possibly less
pitch.  You need to try and get a 2-4 break as well.  What will this help??-  If you are running
the motor with very little break, ie: flat out in a steady speed, when the Score goes above 45
degrees the motor gives no more power then in level flight.  If the motor is set richer, ie: in a
4 cycle in level flight, the model will fly slower and with less pull.  Then, when you go above
45 degrees, more or less, the motor will break into a 2 cycle and give you more tension
exactly where it's needed.  Adding diameter to the prop will give you more tension without
more speed, given the same pitch, and will load the motor much more - so you will have to
set the needle for a breaking 2-4 or it will overheat and sag in maneuvers.
   This is easier to understand if you think about doing exactly the opposite- set the needle leaner
and use a high pitch prop and less diameter...  Doing this would cause the same problems
you are experiencing. -Lots of pull in level flight, but will want to fall out of the sky
when flying maneuvers.  
   Less pitch will help the model accelerate, you wouldn't want to use 5th gear to climb a steep hill
when you're driving would you?  
   It takes some experimentation with different props and setting the needle to give the
right performance.  I do not use a ST51, so I am not super familiar with how it performs in stock
form, but I do know many send theirs in to be re-timed to give a better 2-4 break.  
   Moving the leadouts should also help, but I think a prop change is needed, as well as a
richer needle at takeoff.  I'd also suggest a uniflow tank if you are not using one, and
LESS nitro if you are not using 5%, and decent oil content.  Good fuel helps the 2-4 break.
If the oil content is low and the nitro too high, the engine will not run cool enough to
return to a 4 cycle after breaking into a 2 after a stunt and return to level flight.
   You need to give us more info on EVERYTHING about your setup to give a more
definitive diagnosis.

Stan Bidowski  

I dont mean to sound like a broken record , a St .51 is not nearly enough power to the Score well. 65oz + Try


a .60 with 13x6 prop or Saito. This is a heavy draggy plane!

Lap time was about 4.7 seconds.

I am seeing a common thread here.  Pulls like a freight train in level flight and at 45 degrees the lines get very light.  Also the one answer to this problem is more power.  I will give the 13x4 a try but if that does not show improvement I will move up to more horsepower.  I may move to a 4-cycle .60.
Andy

In my experience, I think you would be well advised to try to get more consitant line tension around the hemisphere before you think about more power. If you didnt have enough power tension would be light all over. Light overheads and heavy level flight is classic symptoms of leadouts to far back, perhaps even excessive rudder offset and engine offset. I dont disagree that proper prop selection will help. But I really think you should explore the leadout position first. That comes right of the magic trim chart.

My Score has been a "work in progress".  It is a big draggy plane, but it turns so well!!

I am running a Tom Dixon ST 51 w/APC 12x6, Powermaster 10/22 on 65' eye to eye, lap times 5.1 or so, take off RPM ~8100/8200. 

After adding some nose weight, to improve level flight tracking, I had LOTS of tension in level flight and little tension above 45*.  I moved the rear leadout forward about 1/8 inch and was rewarded with great line tension every where.

As usual, YMMV........

Cheers,
Jim 

When the TF Tutor II ARF was last offered by Tower, that Chicom 51 was offered with it as a combo, however, I dallied and dithered, and then they were all gone.   But through the kindness of a fellow "Hangarite" here, I did get the plane.  However, instead of that newer 51, I have two of the Italian V-51s to play at aerobatics with.  While I was hunting those down, a V-60 also came my way, but I don't need that for anything I have, other than an unbuilt Magnum.   

I seem to have two things to try the next time I take the Score out.  Replace the 12x5 with the 13x4 and move the cables forward.  Given the amount of pull in level flight it seems hard to grasp the engine power being the problem.  I certainly will listen to the advise that's been given and if a .60 is needed a .60 it will be.
Thanks everybody for you help.
Andy

Master Airscrew doesn't list a 12-5 wood, so the prop is probably a standard Zinger (pretty much guaranteed to not work). I'd suggest trying a ProZinger 12-5 (with some hand work),  12.25 x 3.75, 12-4 & 12-5 APC's, Graupner 12-5 and Thunder Tiger's 12.5 x 5.5 (probably trimmed or repitched or both). I have had wonderful increases in overhead line tension, just with a prop change, so don't give up hope on the G.51 yet! Moving the LO's forward may also be required, of course. Keep after it, and be careful with it, until you get it right. Trimming can be a slow process, but worth it. Patience, Grasshopper!  Steve

The ST .60bb's should be great, if you can stiffen up the nose to withstand the vibration. I'd put in a crutch per Randy Aero or WindyU, and slide the tank in through the engine bay. The .56bb would be worth trying, but the ST.51bb's were said to be weak sisters. They'd all interchange, so you should try them all and see. With aluminum pads, you can also try your various G.51's.  Avoid the engine and rudder offsets. The fin/rudder is too ugly, anyway.    Steve

Is that enya a drop in for the newer G51 or older v case 51?

Hi Gordon:

The ST51 I have is the current Chinese-made version. I did have to drill out the holes in the plastic/glass RC-type mounts to use larger (6-32?) mounting bolts but the bolt pattern is the same. I had to enlarge the fiberglas cowl openings for the slightly different exhaust (using Randy Smith tube muffler) stack location and the needle valve is also different (one could say in the "right" place) on the Enya compared to the ST. Prop shaft length is also very close to same, so no problem with prop/cowl clearance.

The 61CXS Pro looks very well made and starts first flip when propped backwards against compression. Look forward to more test flights and trying different props. Currently using Zinger Pro 12-5, 9400 revs at launch.

61CXS Pro

For the heck of it I went over to Enya to look at this engine.  It seems the 61CXS Pro is very popular engine, "Sold Out".   

Check with Randy Smith and Kaz Minato and the dude in the Canary Islands...all stock Enya stunt engines.  I've heard good things about the service from all three.  Steve

Got my Enyas from all three sources and the best service was from  Kaz Minato and Randy Smith. The third guy took a little longer but acceptiable.

Wow.... I just bought a Score.. and a new ST51 (China)... read the instructions which stated that the T/F folks flew theirs with OS 46LA.... and it flew fine.. they stated a 51 may overpower the plane... I Was thinking about using my italian ST46 G21..... now Im totally confused...    Andrew.. keep me posted as to how this works out.. I havent Installed any engine yet... Thanks...

Chris

Only played with a couple of the Tiger 51 and after lots of different props the Thunder tiger 12.5 by 5.5 was the best on both planes . Didn't try any of the high priced Bolly or Eather they might be better? Ran the engined in a hared four stroke and would break to two going up hill. Ran pantie hose filter on 5% nitro 22% oil half and half. Andrew if you can take some flap out of the plane do so, they work very well but slow it down in turns. If weight dictates you you need them, like if it stalls in turns, you cant take some out but only use what you need of them.

I flew the 64 oz. Score with the Tom Dixon ST 51 today; Zinger 12x5, both sq. tip and Zinger Pro. 
Sig 15 % nitro/20% oil with take of rpm set to 9100.  Sixty five X .018 lines, 5.1 lap times.  Wind was about
5 to 13 mph.

The biggest problem was some wind-up during the inside and outside rounds; and the guy at the handle....

I think the ST was doing about all it can do, and the plane would perform better with an engine that wasn't running flat out all the time. At the 9100 rpm setting, there is a little needle left, but not much.

So, time to get out the hammer and saw........

Cheers,
Jim

  Just to clarify what I typed here earlier, a 4.5 sec lap time is flying too fast, 5.2 or slower is more
like it.  At 4.5 sec lap times, a heavy model will pull hard, especially in level flight.  Also, remember
it was stated a MACS muffler, which is a mini PIPE, was being used.  Using a mini PIPE will demand
the use of a lower pitch prop.

Check out previous issues of Stunt News, were the MACS mini pipe was used with a .40 ( FP or was it
an LA 40 ?).  A low pitch prop was used with good success.  A stock .51 engine is being used, not a re timed
one, and not a ST .46 which requires nothing, no rework, and run fine on a 12 x 6.  Sorry, NOT a good
comparison to a 'PIPED' STOCK ST .51 . 

   Another option is to try flying the Score with out the 'muffler pipe', and a 5 or 6 pitch prop, like others
have here have used with success.  BUT once you add the MACS Muffler ( which is a mini pipe ), you
should be using a low pitch prop, and try to run as much diameter as the motor will turn. 

Stan Bidowski

Try this...saito 62a,65 foot lines,Apc 13-6 prop,20 20 powermaster 4 stroke fuel,line guides way foreward,engine straight on center line.What I got is 5.0 sec laps,great line tension everywhere and the best flying learning machine i've had to date.8400 Rpm at launch leaves a nice contrail againt the tree line.I have the same set up on my Magnum and it's a great flyer too.   JIM

I really thought the TF Score would be the plane I would be able to make serious progress in taking the pattern to the next level.  Truth is it just isn't happening.  I cannot get the trim sorted out.  At stright and level flight the Score darn near pulls my arm out of the socket, but at 45 degrees the pull falls off by more than half.  Overhead eights, verticle eights and hourglass range from  problematic at best to down right scary. 

    That's usually a sign of too much yaw angle, either rudder offset, or line sweep, or both. I think the procedure to use to get it close is pretty well documented, but if that doesn't fix it, it would help tremendously if you could get a local expert to look at it carefully. If it pulls hard in level flight, and the power doesn't grossly drop off overhead, it should pull pretty good overhead, too, if everything is nice and square.

    I haven't been very impressed with the Score. It looks like it ought to be pretty good from the parts,  if a bit heavy, but for whatever reason I haven't seen one that looked very good from the outside, and the two I have flown were really handfuls. Eric Rogers has an electric version that looked pretty decent when he flew it, but Ted flew it and seemed to have his hands full in level flight. I got a chuckle out of that, until I flew it and almost crashed in level flight at almost the same point in the flight he had trouble. I should have known better, if Ted can't make it look good, I haven't got much of a chance.

     Brett

     

I wouldn't give up on the Score.. Several "Experts" have flown mine and were actually quite impressed. Maybe I just got lucky or could be the care I took making sure everything was straight and true when I assembled it. It doesn't hum and with the 4 stroke I'm sure I would hear it, do have to say I believe allot of it's good qualities are due to the brute power of the Saito 56 in the nose.

  I have to admit to not having spent a lot of time trying to figure out what the problem was with the models I flew. I am reasonably sure that there isn't anything intrinsically wrong with the airplane design, but as you say, the details are what matters. I tend to agree with the observation of needing a fair bit of power to fly well, not surprising given that they are frequently in the 75-80 oz range. I would think the Saito 56 is near the bottom of the scale for that weight airplane, even granting that you seem to have a better setup than most. Certainly an ST51 is marginal unless you really lean on it.

     Brett

Brett, I will bring mine up to Woodland this spring and you can try one with an Enya 61CXS at 65 ounces. Certainly I am not in your league of piloting skills but it seems pretty darn good, squares the corners well and (to me) grooves well too. All controls replaced with ball links and carbon pushrods, proper hinges, the works. Once leadouts were adjusted the line tension is good but not excessive at all points on the hemisphere. The controls are too fast (used a 3" bellcrank, what was I thinking) but maybe good combined with my slower reflexes!

 
    I'll certainly give it a try!   A 60 certainly seems like the right kind of power.

     Brett

Hi Martin:

This is good information! I am still in the early stages of experimenting with props on the 61CXS and welcome anyone else's input and experiences. It runs fine with the 12x5 Zinger Pro but I want to try some larger props. I don't know if this is an engine that wants to run fast on a flat prop, or slower on a higher pitch prop. I am kind of splitting the difference. I fly off a fairly rough field that is death on $50 carbon props so I will stick to wood and plastic for now. The APC 13x4W sounds interesting; I will order one and a 13x5 (if they make one) and give it a go.