Big Drak VTOL Conversion

There's now a Facebook group to discuss builds, successes and problems. Come join at https://www.facebook.com/groups/vtolhangout

Oct 5 2022: Added a nacelle and motor mount with an cutout for a 3x6x2.5 bearing on each side to avoid wear and tear on the printed part. Use a 3mm rod for the hinge.

The Nano Drak VTOL has been a success and I had a few requests for a Mini Drak version. The Mini Drak version has been around for a while now so next comes the Big Drak. I'm sharing these files but I haven't actually built one of these but others have and I will list a working spec below. I printed the wing mount portion and it fits the wings well. The tail mount is a beefier version of the one for the mini drak. Hopefully its beefy enough. Feedback welcome. There are 2 versions for metal or ABS plate depending which you have on your Drak.

The nacelles have a hole on the end that allows for an M4 bolt that sits just behind the spar.

The motor in the rendering above is 42.5mm wide and tall. The prop pictured is a 9x6x3 (though I would recommend less pitch).

These are big prints. They may be a challenge to print. The nacelles are just under 250mm long. They may only print on a diagonal on your print bed. I can fit it horizontally on my 250mm bed without a skirt.

Credit for the tilt-rotor design goes to Steve Carlson who designed a fantastic fully 3d-printed plane. Check it out here: https://hackaday.io/project/175286-minihawk-vtol

The motor mounts are designed for 28xx or 31xx or 35xx motors with 19x19 and 25x25 bolt pattern and max bell diameter of about 46mm.

Print using Pet-G for its strength. 20% infill (50% or more for the tail). The nacelles and tilt motor mounts are laid out on their sides. I've had good success printing them in that orientation with full supports. Requires some cleanup with needle nose pliers afterward but supports come out pretty well. Mirror for the other side.

Check out the nano drak for videos and Ardupilot param files: https://www.thingiverse.com/thing:5387189

Here's the Nano Drak maiden video: https://www.youtube.com/watch?v=42L8vE7RcWE

And a Nano Drak build walkthrough video: https://youtu.be/8DG942hFIpE

And a basic Ardupilot setup video: https://youtu.be/4e3JP7eEZIU

Check out my series on the Heewing for a lot of build tips: https://www.thingiverse.com/thing:5348919

Parts needed:

Big Drak

6s battery (suggested)

Specs below from a working setup:

Flight Controller: Matek H743-WLITE

GPS: Matek M8Q-5883

RX: TBS Crossfire Nano RX Pro

VTX: DJI FPV Air Unit

PDB: Matek XClass PDB FCHUB-12S

AirSpeed: Matek Digital Airspeed Sensor ASPD-4525

Front:

Sunnysky X3520-6 KV 720 14-8 Prop

2x HobbyWing XRotor Pro 50Amp

Back:

UAVS BD4112 380KV 14-6 Prop

HobbyWing Platinum 60A V4

Align BL815 tilt servos on 7.2v

Align DS820 Elevon servos on 7.2v

2-56 smooth rod for hinge mechanism, (may have to drill out hole with 5/64” drill bit)

e-z connector like https://www.dubro.com/collections/e-z-connectors/products/e-z-connector

to lock hinge rod in place (bend other side)

4-40 swivel ball link .. 4-40 linkage for the tilt servo.

Category: R/C Vehicles