Line Tension

[James Mills]

I finally got some time to fly last Saturday (first time since first part of June).  It's a new plane, only about 10 flights or so.  There was almost no wind and I was having a big problem with line tension at or above 45*, level was okay.  The plane is one of Allen Brickhaus' designs, Mirada (about 650 sq, PA 61/pipe, 12.25 X 4 3 blade, 68.5 ounces{way to heavy I know}.  RPM at realease was 10100-10300 lap times around 5.4.

The last flight the wind picked up a little and the tension improved.

So my question is how to trim for those rare lite wind days (I know to step back with the plane), but what are some of the other tricks of the trade?

Thanks,

James

[Bill Little]

Elevated and/or overhead tension is increased through airplane speed, tip weight (maybe) and moving the leadouts forward.

Bill <><

[Ron King]

James,

If you want more line tension overhead, move the leadouts FORWARD about 1/8". This may reduce your line tension in level flight and you may have to compromise a bit.

My advice would be to get used to the 5.4 lap time. You will probably be better off in the long run. I've always flown faster, but learned at the FCM contest that the slower plane lets me do better maneuvers.

Take care,

Ron

[Jim Kraft]

( Slower plane lets me do better manuevers)  Ain't that the truth.

[peabody]

Ty:
I certainly cannot qualify as a good flyer, but can attest that moving the leadouts forward significantly increases line tension about 45* in almost every case that I have seen.....

Try it, you'll loike it.

[RC Storick]

( Slower plane lets me do better maneuvers)  Ain't that the truth.

While at the NATS this year and flying the S6B, I had gotten a little rich engine run but not too bad. I went through the pattern and did a fair job. After landing (I can't remember the name) a guy walks over and says did I read the watch right? 6.2 seconds. I said yep ain't it great! MOTOR OFFSET!

[Bill Little]

Sparky,

I build everything 0-0 (with an adjustable rudder usually) except the engine.  It always gets a degree or two of offset. 

If the rudder gets any offset, it is for the glide on landing, or something got messed up during construction that I didn't/couldn't find.

Bill <><

[Bill Little]

One thing in CLPA that has changed dramatically over the past is the custom of offsetting everything to get line tension.  Because of excessive wing panel asymmetry, engine offset, and rudder offset, plus a lot of tip weight, we end up with a ship that crabs through the air.  This really can kill tension when the plane gets higher on the hemisphere and speed slows down.  We want the airplane to fly as tangent (is that the correct term??) to the circle as possible, so as to not kill off airspeed in manuevers.  It is really surprising to a lot of people as to how "soft " the tension can be yet still have (even better) control of the plane.  If it pulls like a Mack truck, it is probably not trimmed effectively.  All the tension that is needed is for the plane to stay controllable at all times.  Excessive tension usually means that something is out of whack.

Bill <><

[L0U CRANE]

Many of the posts to your question seem tied up in general rules of thumb, which may or may not apply to the model you are trying to dial in.

A properly laid out model will fly well at a great range of airspeeds/(laptimes). Imposing the wrong set of "standard practice' guidelines on a model that is a bit different is no help at all.

Where a lot of the suggestions WILL help you is in where they indicate that this is "too little" or that is "too much" by how the model responds. Try to cull that out of the comments. Think about it. Form a test in your mind. If the power system is solid, and all else is well-centered, you can take the cues mentioned and use them positively.

It is worth it! Dialing a model to where you are confident, comfortable and assured feels great! And your flight scores WILL reflect it.

Go for it...

[john e. holliday]

As Lou says think about what you are doing and go one step at a time.  Still working on the trim of the Accentor with the RO-Jet 40 BSRE.  That is one sweet engine.  I now have leadouts a good 1/4 inch ahead of the starting point  on the plan.  Am running the reccomended prop for the engine.  Last time out I was getting comfortable with it.  DOC Holliday