Hand Launched Glider - A summer project

SteveOBHave · 17 Jun 2009 at 19:10

Small update.

I got the razor plane today so I put it to good use and flattened out the bottom of the wing since it wasn't entirely flat due to wood warping. It was a slightly nervous experience because I've already invested quite a bit of time into the wing, I didn't want to have to start again. End result:

The other thing I did was cut out and sand down the tail - it will be a 'V' shaped tail both because the plan says so and because it will be lighter and the less weight on the back the less I will need to balance it out on the front.

I've layed it out in the basic configuration with the carbon fibre tube running down the middle. It's next to a DVD for scale.

YZFAndy · 18 Jun 2009 at 11:48

I have several gliders and mostly slope fly, using updraft to stay up for hours and no need for any kind of motor power.

A nice bit of care gone into that wing section very impressed but the is a couple of things.
The wing section is very thin which isn't a bad thing but will make it fly very fast.
The other thing is without ailerons and a total flat wing it will equal want to fly on it side as the right way up. Most wings without ailerons will need quite a bit of dihedral in them to come back to a level. You will notice the glider you have picture has a split wing that is a slight V angle. This split and v angle is your dihedral and because of the large wing spans of most of these have this allows you to split the wings in two for east transport.

Maybe look at cutting the wing in two, and having a small v brace to join them.

SteveOBHave · 18 Jun 2009 at 11:57

YZFAndy said:
I have several gliders and mostly slope fly, using updraft to stay up for hours and no need for any kind of motor power.

Yeah I'd love to get into a bit of slope soaring but because of my current living situation, i.e. in the middle of London, both slopes and storage space are at something of a premium.

YZFAndy said:
A nice bit of care gone into that wing section very impressed but the is a couple of things.
The wing section is very thin which isn't a bad thing but will make it fly very fast.

The other thing is without ailerons and a total flat wing it will equal want to fly on it side as the right way up. Most wings without ailerons will need quite a bit of dihedral in them to come back to a level. You will notice the glider you have picture has a split wing that is a slight V angle. This split and v angle is your dihedral and because of the large wing spans of most of these have this allows you to split the wings in two for east transport.

Maybe look at cutting the wing in two, and having a small v brace to join them.

As you will see with the plans posted at the start of the thread not only does it call for the thin wing section but it also has provision for dihedral. I'm actually thinking of altering the plans a little to make it a double dihedral, one at the wing root and the other further out similar to this as I think it looks a little more graceful than the one the plan calls for:

Cheers for the comments - I appreciate the positive feedback from someone in the know

Monkey Puzzle · 18 Jun 2009 at 12:04

Looks very elegant.

SteveOBHave · 18 Jun 2009 at 12:06

Monkey Puzzle said:
Looks very elegant.

Yeah it does - now all I need to do is get mine looking like that

SteveOBHave · 28 Jun 2009 at 21:38

Update:

I've done more work on the wing and it's closer to being finished. Weight wise it's quite even and I think airfoil wise it works fairly well. The only thing I can think of that might be an issue is that it's quite thick and as a result possibly heavier than ideally desired.

I've also spent a bit of time sculpting the body of the glider. I'm completely playing it by ear and it's not quite what I am thinking of as a final shape.

It's constructed from 3 sheets of balsa wood glued together. I'm not entirely sure why but it's something that is repeated in plans quite often. Initially I used the razor plane to carve it up and then sanded it to refine the shape. For a first attempt I'm fairly happy with the result but there are a couple of things I need to take into account. One is that there needs to be provision for weighting in the nose, and two that there is provision for mounting the carbon fiber rod into the back of the body. My initial impulse is to take a drill to it but that is still a little further down the line.

So things left to do - I need to create the dihedral in the wing to create stability in the glider which will be a nervous time because I will have to cut it in half. It would be a shame to wreck it.