I recently became interested in DLG gliders after a friend showed me some YouTube videos of the Alula glider and his attempt to build one from scratch. Alula (Flight Test Review)
I built a super simplified version of the Alula and had decent success with it, able to do some slope soaring on a local hill, and also able to ‘discus launch’ it to a decent height. It is not nearly as good as a commercial plane, but I just wanted to try it out without spending over $100. The balance point is very sensitive on this wing, but by using a V-tail I was able to make it much more controllable (ie. less unintentional flipping).
I decided I had to try building a bigger DLG, so using an old carbon fiber golf club and the dimensions of a 1500mm DLG I found on the web I built this in about 2 hours. The wing is a single piece of foam board cut in half. (Parts cost was $3 for club, $1.25 for foam board, used scrap coroplast for body and tail, so I will guess another $2)
It flies really nicely, staying in the air much longer than the small DLG, but the foam wings could not withstand my bad flying skills and broke after a hard nose landing caused by a very bad discuss launch. I replaced the foam wing with a coroplast wing, and it is now a lot heavier but still flies good and seems nearly indestructible after many very bad crashes. The coroplast body and tail slide along the ground really well and never seem to take any damage even when I nosed in hard. I am going to try to lighten the wing by drilling many holes out of the wing and covering the holes with packing tape. Here is the current iteration (weighing 584g, pretty heavy for a glider but ok for slope soaring)
With a hard regular hand launch it will glide over 50 meters. It is also extremely tough, having cartwheeled and nosed-in a few times with no damage. I haven’t gotten very good at doing the discus launch yet, I think that without dihedral it is almost impossible.
Building these two planes has been a lot of fun, can’t wait to try slope soaring it.