emc - mega rubber

NICATO

User
Hello everybody,
I want ask a question:
I bought an elastic from the company emc vega, the long 7.35m diameter of 14.4mm.
I made different measurements and found that the tensile stretching of 15m tested with a dynamometer get to about 17 kg.
I noticed that you can extend more, but for simplicity I stopped at 15m. I now ask:

with this elastic what the maximum weight of gliders that I can run?
With one elastic I can launch a glider 22kg?
to takoff a 12 kg glider just 17/18 kg of traction?
What is the max traction off this rubber?

hi

thanks

Nicola from Bergamo

P. S. sorry for my English, I use google translator:)
 

Merlin

User
Buona sera Nicola,

EMC-Megarubber Scale 4,8 / 14,4 mm
For airplanes from 2200 to 9000 g

Usable stretch is up to 600 %
Force appr. 20,1 / 24,4 / 28,0 kg @i 300 / 400 / 500 % stretch

Typically you need a force 5x the mass of the model. Weight 4kg -> Force 20kg <- 300% Stretch.
But i´m not sure you can hold the plane by yourself

BTW: For what kind of plane do youn want to use the scale-bungee?

Regards,
Bernd
 

NICATO

User
thanks Bernd,
emc vega site I had seen him, but I think to start with the traction 5x the weight of the model is exaggerated.I think that will never come to 600%
I saw take off with a one rubber gliders to 14kg, with a 2 rubber glider to 18kg. But in either cases i think the power was monstrous, so much.
I've never been able to measure the traction.
I wanted to know if anyone tried to use only ONE rubber to start large gliders <18/20 kg.
I have gliders from 10kg to 22 kg; takeoff from mountain.

regards

Nicola
 
It depends on the mode of elastic launch you intend to use:

Classic high-start (like winch-launch) with a long nylon line, where you pull a glider to heights like a kite.
Bungee start, where you accelerate horizontally and catapult a glider capable of high speed to high altitudes.
Launch support at the slope, where you need the bungee simply to accelerate a heavy glider that cannot be safely started by hand to a safe speed and maybe 5 m elevation.

500% force is only required in the second case. There obviously force means acceleration, means speed, means height.
 
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