3D printing a Plane (the struggles of a high school senior)

[RyanAlexander]

Hi all, Im new here, and ive been designing a plane and 3D Printing it. I've been working at this well over 4 months, as im on Version 14 haha (originally was a glider that slowly morphed into a full powered airplane). But im looking for outside help. The plane is just about 20 inches long, with a 33 inch wingspan. It has a 5 degree dihedral, and the normal control surfaces. For electronics, im using everything from the Power Pack B, small fixed wing aircraft with the 10 inch propeller. With previous versions, Ive made the wings out of 1/4 inch balsa shafts and ive wrapped them in plastic wrap and shrunk them. The plane would taxi great, as it was light(er) than now, with a 200 ft hallway. With previous versions, it would take off from the ground, but would always roll left or right, and crash (the hallways at my school at 10ft or so wide) But ive come to the conclusion that as my first plane, i should have ailerons. Making wings the same old way wont work, as you cant really mount servos on plastic wrap and I started to print wing segments. Each completed wing is 15 inches. Now, with the added weight, the motor cant simply pull up the weight. As a test, i held the plane vertically and put full throttle, and it came clear that it was too heavy. At the moment of this post, I have (hopefully) a lighter wing segment printing, as the infill density has been decreased dramatically. If there is nothing that can be done about the weight of the plane, what motor and esc can i upgrade to? As being new to this hobby, i know very little about matching ESC's, Motors, and batteries. The electronics im using are all in the Power Pack B. I know that the ailerons are on the smaller side, and in the future I will make them bigger, but Im more concerned about getting off the ground that anything else haha

Any help or input would be amazing!

 

[Hai-Lee]

Firstly there is a requirement for the motor to angled with respect to the planes centre axis. The angle called side thrust angle is required to overcome a phenomena called "P" factor. The result of the propeller providing thrust is that you also generate a spiral of high speed air, this results in a sideways push on the fuselage and the vertical fin. The side thrust is required to reduce the sum of forces attributed to the "P" factor to as close to zero as is possible.

I am not sure of your current design but most flying 3D printed birds are normally printed hollow like a vase with a lattice or geodetic structural component where required. If you are seeking a very light structure research geodetics and cover the craft with as light a covering as is possible. A classic geodetic design was the wellington bomber for your reference.

More info on your design would be appreciated!

have fun!

 

[FDS]

Printed wing segments will be very heavy. Plus there is no way you can fly in a hallway, not with fixed wing. You will need a very large gym or calm day and a field.
Your three channel design sounds like it was a much better proposition, you just need more room to test it to see how it can be improved.
If you are dead set on ailerons remember you can have a servo mounted in the body with the ailerons controlled by linkage, which might be easier to put into your nice light wing.

 

[Arcfyre]

If you are dead set on ailerons remember you can have a servo mounted in the body with the ailerons controlled by linkage, which might be easier to put into your nice light wing.

@FDS said exactly what I was going to recommend, that being a single fuselage mounted servo to control ailerons. This setup would allow you to use a lighter wing and help get your plane off the ground with the B pack.

 

[FDS]

There are pictures of this set up being used on FT minis, an example here, which mentions a pre built linkage option.
You could also consider a foamboard wing, there’s several mini designs that might work well with a very light fuselage, they often have mounts for 5g servos incorporated into the design. You will need to print the fuselage as a honeycomb with absolutely minimal infil or go to a larger wing. The Tiny Trainer 3ch wing is a good one for stability and lift. If your fuselage is heavy then something like the explorer 4 channel might be worth a look.

 

[mrjdstewart]

go to 3dLabprints and follow their printing instructions. it should be very, very thin with almost no infill.

good luck,

me

 

[RyanAlexander]

Firstly there is a requirement for the motor to angled with respect to the planes centre axis. The angle called side thrust angle is required to overcome a phenomena called "P" factor. The result of the propeller providing thrust is that you also generate a spiral of high speed air, this results in a sideways push on the fuselage and the vertical fin. The side thrust is required to reduce the sum of forces attributed to the "P" factor to as close to zero as is possible.

I am not sure of your current design but most flying 3D printed birds are normally printed hollow like a vase with a lattice or geodetic structural component where required. If you are seeking a very light structure research geodetics and cover the craft with as light a covering as is possible. A classic geodetic design was the wellington bomber for your reference.

More info on your design would be appreciated!

have fun!

The fuselage, nose, and empenage are formed from a solid shape, and is 1/10 thick. Ive never had a part break from one impact, although the nose did break after one after noon of slams. The horizontal stabilizers are solid (i think). The default infill setting is 10%, and I printed a new wing segment with 3% infill. It was lighter, although the top was flexing. I could try printing them again with the new infill setting, but i assume they'd be very fragile.