FT3D EPP with removable wings

Hello everyone!

For my second article on this site, I'd like to present my upgrades on the FT3D.

History :

3 years ago, I had already built a depron version, but it was too fragile and a little bit unstable :

After this crash I rebuilt one with depron again, but it does not stop me to make a third, this time with EPP, in order to make it more durable : It's this last version I will present you today!

Moreover, having built this aircraft in depron several times gave me ideas for improvements :

• The wings will be removables,
  because it is more convenient for transport and storage, even for a small model
• The wings will have a real airfoil (naca 0012) to improve the performances.
• And the access to electronics (ESC, receiver, battery) will be easier thanks to a larger canopy

The construction :

If you want to realize the same kind of project, here is the list of tools I used :

• An automatic hot wire machine for the wings, but you can use a homemade hot wire cutter and custom made balsa templates, like in this video of flite test : https://www.youtube.com/watch?v=fi3CAtpvJJs (/!\ be careful with the EPP and the hot wire : we need the wire moving VERY slowly and NOT overly hot !)
• An electric jigsaw for the ply wood parts
• A modeling knife or a cutter with a new blade
• A hot glue gun to glue the EPP fuselage parts together
• A "5 minutes" epoxy tube to glue the ply wood parts (together and on the epp)
• A pharmaceutical tape for the hinges, but you can use reinforced tape too
• For this model, I used one sheet of 5 mm EPP for the fuselage (900 * 600 mm) and one block of 40 mm for the wings
  

So, here is the result of the automatic hot wire machine for the wings :

Then I cut all the pieces for the fuselage into a sheet of 5 mm EPP :

The build of the fuselage is very close to that of Flite test, except I added a simple ply wood structure in order to rigidify the fuselage, and support almost all the electronics (engine, battery, receiver, ESC) :

In the next picture, you can see that I closed completely the fuselage without doing the canopy of the flite test plan :

Then, I cut the new canopy until the ply wood structure, with my modeling knife.

This canopy is held in place with a piece of depron at the front, and a powerful magnet on the back.

The other magnet is glued below the rear reinforcement.

For the joiner of the wings, it's a simple carbon tube from kites. I cut the holes in the wings using this trick :

And they are kept in position thanks to two hooks and a pen spring :

Finally, here is a picture of the model complete and ready to take off :

Flight and conclusion :

Here is a video of the model flying :

In flight, I was suprised by the behavioral differences between my depron version and the EPP version with the naca airfoil : it's much more precise in the controls, and really pleasant to fly.

I had just one problem : the EPP rudder is a little bit too flexible, so not efficient enough for hard 3d flights. It needs to be reinforced with a piece of carbon for example.

Thank you for reading this article, I hope that you enjoyed.
Sorry again for my english mistakes.

If you have any questions do not hesitate, I'm always interested in your feedback.

Jeanbat.