100S

[Tony]

Question. What pull force do you get on a winch. Asking as I've never used one and I'm in the process of designing a new set of wings and tail feathers for an unused EMP Algebra fuselage I have as I fancy having a go at the 100S. Does it need to be as strong as the Allegro Lite/Bubble Dancer.

Tony

[satinet]

Hi Tony

It's hard to say, as a lot depends on the wind speed. You can snap line that is say 1.2mm in strong wind (say 120lb strain?) with f3b models.

The times I've seen models blow up and I've done it myself are the bottom of the "bucket".  i.e After you've dived off the line and gained speed through the elasticity of the line you then pull up to get the final height (aka the zoom). The high speed and sharp turn creates a lot of G on the wing.

If you are using f3b spec winches and mono line, yes it wants to be strong if you are going pedal to the metal for max height.

Tom

 

[thermaldoctor]

You can control the amount of force to quite a large extent yourself by having a more forward tow hook position and having a certain amount of down elevator preset in your launch set up. If you then launch and feel the wing is still nearing its breaking point then you can manually feed down elevator in to bring it back to a safe limit and not dive and ping too hard or too sudden.

As Tom says wind speed will also play a large part as well.

If you are thinking of flying in a UK competition, then you must assume you will forced to fly in higher wind speeds. This can load the plane quite dramatically in both bending and torsion. In competition, the adding of down elevator and forward tow hook positions will lose you time on the line and particularly lose you altitude so you won't want to give too much away when you see others getting in the air faster and higher than you.

Strain wise I always estimated that the average pull during launch was in the region of 40kg-50kg. When the wind gets up I estimated this to be more in the region of 60-70kg. This is only an estimate and is based on various 3.8m F3j airframes set up to their absolute optimum. I would think a 100s model would pull significantly less than this especially given the lack of additional launch camber but I would still build one as strong as you can manage especially for UK conditions where additional weight is not necessarily a disadvantage

Hope this helps

Neil

 

[Tony]

Thanks both, so I'll aim for around the 150lb mark