Flyer Mk. 1a Modifications

Base on experiments and suggestions that I have received from discussion forums (particularly the rcgoups.com 'Free Flight ' forum), I have designed some improvements to my Flyer Mk. 1 design, which I am now referring to as the Flyer Mk. 1a. I have had some decent flights with this new version of my plane, and you can see some of them at https://youtu.be/U_MD9a3IsKE.

The Flyer Mk. 1a modifications consist of three new wings and two new propellers. The three new wings for the Mk. 1a have the same size and airfoils as the Mk. 1 wings, but the spar structure is different. The Mk. 1 wing spars extend from the bottom surface of the wing, but are not bonded very well to the top surface of the wings. This decreases the rigidity of the wings, especially for the wing design with the thin, under-cambered airfoil. The Mk. 1a wing spars extend in 5 mm long alternating sections from both the top and the bottom of the wings. This makes the spar bind to both the top and bottom wing surfaces, which increases the stiffness (and hopefully the strength) of the wings. This is especially noticeable with the thin, under-cambered wing design.

The two new propellers have steeper pitches than the original Flyer Mk. 1 propeller. The original Flyer Mk. 1 propeller has a pitch of 260 mm, and a diameter of 200 mm, which gives this propeller a pitch/diameter ratio of 1.3. Both of the Mk. 1a propellers are also 200 mm diameter, but one has a pitch of 300 mm (for a P/D ratio of 1.5), and the other has a pitch of 340 mm (for a P/D ratio of 1.7).

I encourage you to experiment with different combinations of wings and propellers. The combination that seems to work best for me is the thin, flat-bottomed wing with the 200 mm dia. x 300 mm pitch propeller.

The attached files only include the STL files for the new wings and propellers. To print and build the rest of the airplane download the files for the Flyer Mk. 1 design at https://cults3d.com/en/3d-model/various/flyer-mk-1. If you want to explore these files in your CAD system, I have included STEP files for these new wings and propellers as well. There is also a PDF instruction document which includes detailed printing, assembly, and flying instructions.

I am really looking forward to seeing someone else print and fly one of these airplanes. AFAIK, I am the first and only one in the world to successfully print and fly a 3D-printed rubber-powered model airplane. Who will be the second?

For full printing instructions, please refer to the instruction document included in the files for this design. In order to make these parts as light as possible, you will need to print them with a 0.3 mm nozzle on your printer. The wings are to be printed from Colorfabb Natural White LW-PLA in vase mode (or, with 'spiralize outer contour' turned on in Cura). The propeller is to be printed from conventional PLA, but I recommend you use one of the 'PLA+' filaments to make the propeller as tough as possible, since it will have to survive some hard landings. (I find that eSun's PLA+ works well for me. It has been a while since I have broken a propeller blade.) For further information, refer to the instruction document.