Line Tension ... Help Please!

[Robin_Holden]

Greetings guys and advice please .

One of my favourite models is my Sig Banshee , equiped with a terrific Byron Barker [ real gent !] modified Tower 40.

It has , as we all know , fixed leadouts. I cannot change the tip weight either !

Now my question is : Can I increase the line tension by changing props ? Does an increase in pitch increase line tension ?

Any suggestions would be really appreciated fellas ,

Much obliged , love this forum .... A godsend to a 'returnee' to Stunt.

Robin [ ex-pat Brit in the Charente full of ex-pat Brits ]

[Dennis Moritz]

Check alignments. Make sure the vertical tail, fuse, aren't offset, even slightly towards the center. Also check for wing warps or misalignment's between the stab and wing. Wing warps can be twisted out of a Banshee (or Twister) fairly easily. Since the wing isn't a D or C tube. If you're flying outboard wing high, upright and inverted, slit the wing tip and glue in tip weight. You can either mount a tip weight box by cutting and patching the outboard wing, or simply slit the covering on the wing tip, glue in weight and seal the slit with clear packing tape. Once you've got the trim right. You can patch the slit with silkspan or monokote. If your stab is off alignment, either cocked up or down, or misaligned looking down from the top view, wing tip/stab tip closer on one side or the other, cut the stab loose and re-glue. You can add engine offset with either offset wedges (Brodak has them) or washers under the front mounting screws. Lead outs can also be adjusted, if need, by slitting the covering and re-gluing the lead out location. I've never seen a pristine Banshee. Don't be afraid to scar your pride and joy, while making improvements to trim. Adds character.

[Chris Gilbert IRL-1638]

My limited understanding of this is yes, but.

The "but" is that what you are really doing is changing the model speed and making the model fly faster or slower ain't going to fix any inherent alignment/trim problems. If anything its going to make trim problems worse.

Tip weight, CG and maybe rudder offset are your friends here, though what you're doing with all of these is trying to make aerodynamic centre of the airplane line up correctly with the leadouts, not the other way around.

Cutting and retrofitting a tip weight box, tail weight box and a lead out guide (assuming your leadouts are long enough) is the way to go here in my opinion.

[james dean]

Hello Robin,

Increasing the diameter of the prop will help, also, increasing the tip width of the prop will both help line tension above 45 Deg.

I run my LA .40s and .46s in a 2-2  fashion w/flat pitch props in the 4 in. range w/Randy Smith tube mufflers.

This gives me a great engine run that will not gain speed in the wind during manuvers.  Your .40 is similar to the LA .40 if not a direct copy.  It will want 5 to 71/2 % nitro w/22/24% oil 1/2 castor 1/2 synthetic.

Try a APC 10.5 X 4.5 on this and you will be happy.  Launch at 10.2k rpm.   

James

[Robin_Holden]

Just a word to thank the fellas for their advice and contributions.

I'm very much obliged ,

Robin.

[Larry Fulwider]

. . . I cannot change the tip weight either !
 . . .
Robin [ ex-pat Brit in the Charente full of ex-pat Brits ]

Robin --

A handy stick-on weight is lead golf club tape. It is used by golfers to adjust swing weight, and if it stays on a golf club through impact, it will stay on a wing during a square corner. I've used it with no problems as a "temporary" trim adjustment (for a whole season  )

You can buy the tape at a specific grams / inch (or cm), so even with no scale handy, you can add precise amounts. It is not particulary decorative, tho.

     Larry Fulwider