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By flyingcat
#406351
When coming for landing and pushing out with authority on zero wind conditions, how much force do you all think that one is putting on with your arms/shoulders/back muscles? your whole body weight + that of the harness + that of the glider + air resistance? or how one would go about calculating that?








User avatar
By DMarley
#406360
The only sure way of obtaining accurate data on each landing would be to put strain gauges at the pilot's flaring hand positions on the DT's, then if using cylindrical DT's, it would be reasonably easy to calculate the force applied. Slightly more complicated with aero DT's.
You could also use pressure sensitive pads as well, that might be a bit easier to calculate, especially with aero DT's. All strain gauges / pressure pads would be connected to a microcontroller to read and store the data.
The flaring force would be unique to the glider model, glider tuning (including VG setting), glider size, DA, the slope of the ground, pilot skill and mass, etc. But I think it would be much less than what you appear to be thinking. I'll guesstimate less than 20 lbf (89 N) total for nearly any modern glider landing on flat ground. Perhaps less than half that (5-10 lbf?) for many gliders, especially well-tuned gliders and those with higher aspect ratios and less washout.
User avatar
By miraclepieco
#406362
Sounds like one of those inane theoretical exercises concocted by people who are busy finding excuses to do other things than actually fly. I'll bet Manfred Ruhmer frets over this question constantly.

Everything in the system is on a flexible central pivot using the leverage of downtubes so surprisingly little force is required to flare. I'll go out on a limb and say 18.2 lbs, or 8.55 kg. Wanna bet if someone actually puts gauges on their glider that this WAG is pretty close?
Sounds like a project for Steve Aden, the only person I know who flies AND calculates all this technical stuff.

You're welcome, glad I could help. Now go fly and write us a thrilling story of your exciting adventure instead of this didactic Pagen-esque ANAL-ysis.
User avatar
By DMarley
#406366
miraclepieco wrote:
Sat Jan 26, 2019 4:12 pm
Sounds like one of those inane theoretical exercises concocted by people who are busy finding excuses to do other things than actually fly. I'll bet Manfred Ruhmer frets over this question constantly.
Have you noticed where flyingcat is from? It's quite possible that the weather there is not flyable. At least not as often as where Mikey lives and flies. My flying sites are crap this time of year. The wind rarely if ever cooperates here in the winter months, so I have plenty of time for dreaming of flying and concocting other means of achieving flight. If you're not questioning things, then you're merely accepting the status quo.
Everything in the system is on a flexible central pivot using the leverage of downtubes so surprisingly little force is required to flare. I'll go out on a limb and say 18.2 lbs, or 8.55 kg. Wanna bet if someone actually puts gauges on their glider that this WAG is pretty close?
Pounds and kilograms are not units of force, Mike.
Sounds like a project for Steve Aden, the only person I know who flies AND calculates all this technical stuff.

You're welcome, glad I could help. Now go fly and write us a thrilling story of your exciting adventure instead of this didactic Pagen-esque ANAL-ysis.
Why is Mike so pherking negative and condescending all the time? Not enough flying perhaps?
User avatar
By Karl_A
#406539
Geometry is always a factor: how long the pilot's torso and arms are as well as upright hang height.

Force is less of a factor with higher aspect ratio gliders because they have less pitch stability and pitch damping.

Flare geometry is easier to measure than force.
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