In this lesson, we'll learn how to measure physical properties.
After completing this lesson,
you'll be able to apply a physical material and measure mass properties.
Our XStar design is progressing really well at this point.
We know that we're going to have to add
a bit more material because we need to hold the components.
We need all the battery,
the flight controller, all the rest of the components that go along with this design.
But it's never too early to apply some physical materials and start to
understand how much mass we have and how much we're dealing with.
So, we want to start by right clicking on
the XStar Body inside of our bodies folder in
the browser and we want to select physical material.
We have some options here and what we want to look for,
is the plastic folder in the library and we want to scroll down until we see nylon.
So, we're going to be using a nylon
6 and we can either double click on it because we have the body
selected or we can drag it over and drop it onto that body and close.
So now, the XStar body has a physical nylon material applied to it.
The end goal for this part is to be printed with an SLS machine using
a nylon type material whether it's straight nylon
or has glass or carbon reinforcements in it.
It's going to be relatively close to the mass of that nylon 6 material.
So, now we're going to right click on XStar Body and we want to look at the properties.
So, in that same area where we selected physical material,
we're going to select properties and with the body selected,
it's going to bring up the properties.
It's going to show us the area,
the density, the mass,
the volume, the physical material that's applied and the appearance.
There's also some various things such as the location of the center of mass,
the moment of inertia as well,
as the moment of inertia origin.
One of the great things is you can copy all this information directly to
the clipboard or we can simply look at it directly in here.
So, what we want to focus on right now, is the mass.
When we're starting this course,
we looked at the overall mass of our components;
the electronics are about 300 grams,
the batteries range from about 107 a piece to 260 a piece.
So, we have a range of what we want in terms of all the components in the batteries.
The only variable that we really had to play with other than changing batteries out,
was the mass of the body and while the final mass,
the location of supports and all that is really
critical for the engineering side of things.
It's never too early as a designer to consider these in your design.
So, we've done as much as we can to make it as
minimal in terms of the frame, making the eye beam,
making the structure and what we have right now,
is a mass of 225 grams.
And this is really good because our target is about 300 grams.
We don't want to exceed 300 grams and obviously the lighter the better.
It's going to give us better thrust ratio,
we're going to have more maneuverability in the air but there is
a certain point where we're going to either be too light or too heavy.
So, at this point in time being at 225 grams,
giving us about 75 grams to play with,
to add more mass to hold all of our components and
add additional structure is a really good starting point.
This is also a great way for us to evaluate what we have,
make changes and figure out
exactly what those changes mean in terms of the overall design
because of flying design like this quadcopter
is very critical in terms of mass and mass location.
It's a great tool for us to really figure out what those changes mean.
We'll get into more of these changes in the engineering section
where we start to talk about adding more material back,
making it a little bit more structurally sound.
But, again at this point in time,
make sure that you're able to apply the material and evaluate these properties.
Also, note that the center of mass value,
in this case the center of mass is located at zero in terms of the X direction,
Y is 44 which is vertical and that's
okay because if we look at this thing from the front,
remember we're about 76 millimeters up to the top.
So that puts us almost in the middle at 44,
and of course we don't have any components yet.
We don't have the mass of the motors or the batteries or anything like that.
But in terms of the the body itself,
that's a really good point to be in.
If I pull this away,
we can take a look at these values and resize it or again like I mentioned,
we can actually export this to our clipboard.
So, I'm going to go ahead and say okay and take a look at this value on the clipboard.
So, you can see here that the location of our center of
mass and the X is really close to zero.
We're out at four decimal places 0.0001.
So almost exactly zero in the X,
almost exactly zero in the Z and again it's about 45 millimeters up in the Y direction.
So as we look at this from the top,
the X and Z direction,
it's located almost exactly at zero.
Now, out to four decimal places is
negligible especially when we're talking about something like this.
Now, if we were talking about thousands and thousands of pounds,
maybe that would make a bit of a difference but at 200 grams, it's nothing.
It's just potentially a rounding error.
There might be, maybe a difference
in a fillet on the front rather than the back or something like that.
So, everything looks really good here and I'm really happy in the fact that we have
225 grams up to this point that gives us enough of a margin of error,
enough room to add all the extra stuff we need,
and still keep our target weight of about 300 grams.
At this point again, go ahead and save your file and we can move onto the next steps.
