Control of the center of gravity?
Control of the center of gravity?
08-04-2014, 07:28 PM
#13
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Best ive used ok up to and incl1/4 scale cub i have.Sturdy well made accurate.
i tried fingers, vanessa rigs and home made balancers but none are as consistent across a wide range of high, low wings elec to 120 glow that i have
http://www.hobbyking.com/hobbyking/s...airplanes.html
i tried fingers, vanessa rigs and home made balancers but none are as consistent across a wide range of high, low wings elec to 120 glow that i have
http://www.hobbyking.com/hobbyking/s...airplanes.html
08-05-2014, 03:20 AM
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Depends on the size of the model.
If it's under 15 Lbs or so.... 2 fingers, and a helper.
If it bigger... I use a stool, and a section of pipe. The stool allows clearance for the landing gear to hang down... and you can roll the model back and forth on the pipe to find the CG. (And it can rock back and forth on the pipe)
I guess if it got very big or heavy, that wouldn't work... but I've been doing it that way for +30 years now.
If it's under 15 Lbs or so.... 2 fingers, and a helper.
If it bigger... I use a stool, and a section of pipe. The stool allows clearance for the landing gear to hang down... and you can roll the model back and forth on the pipe to find the CG. (And it can rock back and forth on the pipe)
I guess if it got very big or heavy, that wouldn't work... but I've been doing it that way for +30 years now.
08-05-2014, 05:21 AM
#17
There is some really good info at JPO's website:
http://www.jetpilots.org/
Go to "Members" section, then click on "Weight and Balance"
I've done the pendulum method as well myself, and had good results. Put a line around the nose, and the tail, bring them to a common point above the plane, then hang a plumb bob under that same point. Adjust the line going to the nose and tail such that the plane hangs with a slight nose down angle, and your plumb bob will be pointing at the balance point on the plane. Where you put the line around the nose and tail really doesn't matter.
Good luck,
Lance
http://www.jetpilots.org/
Go to "Members" section, then click on "Weight and Balance"
I've done the pendulum method as well myself, and had good results. Put a line around the nose, and the tail, bring them to a common point above the plane, then hang a plumb bob under that same point. Adjust the line going to the nose and tail such that the plane hangs with a slight nose down angle, and your plumb bob will be pointing at the balance point on the plane. Where you put the line around the nose and tail really doesn't matter.
Good luck,
Lance
08-05-2014, 12:23 PM
#23
I have on occasion built hard points into the fuse at the recommended cg. than drilled small holes on that positionyou can bend some piano wire into an L shape ..slide it in the holes and lift it all by the wires...just another technique I haven't seen mentioned. yet
08-05-2014, 01:34 PM
#24
Build a wing former out of 1-2 mm carbon fibre or fibreglass sheet drill a number of holes where the C of G is located, slide formers on and wings on and hang from solid object. ( roof truces)
If you have small hooks on the rope or cable you can easily move these to the different holes you have drilled on the former to get an exact C of G.
Good luck trying to use your fingers on a 15+ kg plane.
If you have small hooks on the rope or cable you can easily move these to the different holes you have drilled on the former to get an exact C of G.
Good luck trying to use your fingers on a 15+ kg plane.
