Line Tension
 

Im flying a little control line. One of my favorite planes is a 35 powered flitestreak. Im starting my takeoff crosswind. As I takeoff for the first few feet I have very little line tension. After I get up a litte speed the tension improves and after one lap I have about 2 pounds of tension I would estimate. After the engine dies again the line tension slacks off and if it dies on the upwind part of the circle I sometimes have to back up to maintain tension. I could offset the engine but that wouldn't help when the engine is off. Should I have more rudder?, Tip weight? Will listen to answers.

RE: Line Tension
 

Add a little tip weight first. I always use offset thrust on profiles, usually on full body C/L Stunters, too.
Chris...

RE: Line Tension
 

I'm no great expert, but what you describe sounds normal to me. It's not unusual to have to back-pedal when taking off and after the engine quits. Take-off should always be down-wind so that the first half lap is on the down-wind side.

Tip weight should be enough to balance the weight of the flying lines so that the wings of the plane stay straight out from the lines, upright or inverted.

Line tension under power is influenced by out-thrust, rudder offset and also leadout exit location and CG. It's a balancing act (no pun intended) to get things optimal.

Good luck!

Phil

RE: Line Tension
 

Good advice so far, for sure. But I'll add a bit more. Learn to whip. It's one of the basic control line techniques.

Whipping is actually a rules violation in rat race because it assists the model so much. The description of the rule violation is actually a good way to describe what whipping is to someone who doesn't know about it. If you draw a line from the model to the centerline of the pilot, if the pilot's flying hand is ahead of that line, he is whipping. Basically, you provide energy to the airplane by pulling the lines SIDEWAYS instead of taking up slack by backing across the circle.

In racing events, you can't exactly back out of the center anyway. But leading the airplane with force into the handle helps the airplane deal with the line drag. It also insures that the inside wing isn't getting yawed backward.

It's actually possible to whip fly a control line airplane deadstick for lap after lap. Well, for as long as you've got the strength to do it. That magic act also shows how the downwind side of the circle helps our CL planes fly too. So as suggested, take off downwind to get that help for your takeoffs. It gives the benefit of the acceleration distance gained before the airplane has to start up wind.

Anyway, whipping works. Next time you've got the plane up and at speed, just put some effort into your flying hand. Instead of just letting the handle pull toward the plane, you put some force into it toward the left. It works as good as backing up, and you don't leave the center of the circle, once you get the hang of it.

RE: Line Tension
 

All I would add to Da rock's encouragement to whip, is to learn to identify when your engine is about to quit, and really put your effort into whipping then. It'll give you more control to set the model down pretty much wherever you want or need to.

Good luck mate.

RE: Line Tension
 

You also need to consider line diameter and length. For .35 engines, .015x60' cables are preferred by most flyers.

George

RE: Line Tension
 

R/C guys who watch me fly are often amazed how I land the plane right in front of my gear. They're watching the plane, not me caressing it around the circle by whipping it.

RE: Line Tension
 

Thanks for all the help. Ive added a bit of tip weight and out thrust of about 2 degrees- now I will give it a go and see. Thanks again !!

RE: Line Tension
 

Don't forget, you should take off downwind, it's important on a breezy day.......John

RE: Line Tension
 

Another tidbit related to the advice above is to MAINTAIN AIRSPEED when an engine quits. Some allow the model to slow by allowing the nose to come up or by trying to hold level which is OK if your position so permits.
If you zoom up and slow quickly usually resulting in being over some 30* +/- bank, then you may well turn the model into yourself or at least slide into the circle. When an engine quits, continue flying and keep up the airspeed with a shallow dive until you determine exactly where you are going for.
Enjoy!