500 Size 3D Printed SA-341 Gazelle

Despite having around 10 projects running in parallel, I recently started another one, a 500 size 3D printed Gazelle from Mastercraft. The Gazelle has always been a difficult one to figure out due to the small fenestron, but I wanted to try out a few things. First, it was a chance to try a 3D printed airframe. Second, I wanted to try a direct motor driven fixed pitch tail. Recent props from cinewhoops have had increasing numbers of blades and even had 8 blade props available. As soon as I saw those, I wanted to use one to mimic the look of a fenestron without the complexity of a traditional one.

I threw together a quick test bed to try out the concept. Started with a beater Trex 500 and removed the tail gears and belt, then 3D printed a fenestron housing and motor mount from PLA. While I didn’t have a spare 3 blade head, I did have an extra Align 4 blade. I figured more torque would be more conservative, so I fitted it to test bed as well. Setup of the motor driven tail was easy. I just used the Brain2’s option for motor tails, and put the tail ESC in airplane mode.

After a few tuning flights I was very impressed. The tail had excellent performance. No authority issues, and minimal (if any) impact on flight time. I also ballast the aircraft up to max gross weight where it could barely hover, loaded down with a 6S 4000mah pack (flight battery) and a 6S 5800mah pack (ballast). I then did collective pulses. The tail didn’t even waver. Next steps are to obtain a 3 blade head, and keep printing, sanding, and painting the fuselage. Planning on finishing the model in an RAF Red/White Training paint scheme.

Here’s the components I used for the tail:
Motor: MqExA5i6JcPojZygJivjs_6sqlYv238zixmAnhs1PvZZSDaTLj SU
Prop: https://www.racedayquads.com/collect...6MMtKVih8IRY4Q tMSft-vqz8VlxwSZbzDx0PA
ESC: HobbyWing V4 60A Platinum (massive overkill)

Link to the parts that I designed for the test bed: https://grabcad.com/library/trex-500...hVr3kJRBzcMRIb BQZOBm9EmrYMIIrR-pWY

A few more updates on the Gazelle. Have been busy with a lot of priming, filling, and sanding to get a smooth finish over the last few weeks. Also ended up doing a lot of modding to the original aircraft. The H-stabs were too far forward as printed, so I relocated them to the scale position. I also cut off the oversized tail rotor drive shaft and used an aluminum tube to make a smaller, more scale version with resin printed bearings. In addition, I fabricated some skids from brass tubing that were substantially more scale than the included 3D printable versions. Finally making progress. Next will be doing the rivet detail.

More progress on the 500 size 3D printed Gazelle. Riveting is complete. First coat of each color is on, and the windshield sections have been formed. Need to print a new nose section, but it’s slowly getting there! The extended main shaft is being turned, and I’ve got the 3 blade head on the way.

Continuing to make slow progress on the Gazelle. All of the windshield plastics are finally glued in place, and the motor driven fenestron is installed. Starting to work on the interior and experimenting with some ways to get the battery farther forward and not interfere with the panel or pilots. Finished modeling the panel, and will be printing a test version soon.

Finally finished up the exterior of the fuselage with all of the markings. Next will be the interior details and panel

Finally finished up the 3D printed Gazelle this morning, and flew it in the afternoon. Finally has pilots and an interior. The direct drive fenestron performs quite well, even in though winds.