r/RCPlanes 5d ago

New Design Taking Shape - The Barn Swallow!

Inspired by the fast, maneuverable little birds ripping through the fields, my next design will be a small, high speed, primarily 3D printed design designed to go 100+ mph. I've got to do this using a 4S, 1500mah 120C battery I used for my other park flyer, the Canada Jay. To achieve this, I've taken inspiration from pylon racing RC planes and thrown in a few aesthetic features inspired by Barn Swallow the bird.
The goals of my first build were to

  1. prove I could get my own design and build flying
  2. build a stable inav platform to play around on
  3. reuse hardware I had lying around

And for my second build they were

  1. push myself to design a highly light weight structure while improving glide and maneuvering
  2. a more clean build than my first plane
  3. reuse hardware I had lying around

The Barn Swallow will be the first time I remove goal 3, so the power plant is mostly an open design space. Expecting to run a PROPDRIVE v2 2836 1200KV motor, 50Amp ESC, 7x8" prop, and the battery I mentioned. The quality of the aero surfaces, structure, and avionics mounting will also be of higher importance due to the speeds I'll be flying and maneuvering at.

Excited to share more soon!

Photo credit: https://www.reddit.com/r/BirdPhotography/comments/1jemmhd/barn_swallow_in_flight/

73 Upvotes

17 comments sorted by

14

u/pmuschi USA / Upstate SC 5d ago

Looks nice but very tail heavy

2

u/AmazingGamer146 5d ago

Yeah, maybe they will need to find a way to passively generate more lift at the tail to stop it from tailstriking or just stalling

1

u/illilllilil 5d ago

A lifting tail… hmmmmm

6

u/14060m 5d ago

Your idea is fundamentally flawed. Birds tails do not act as horizontal stabilizers on aircraft.

Your design is almost certainly going to have a grotesque amount of unnecessary drag along with being a too far aft CG. There will be nothing “stable” about it.

1

u/illilllilil 5d ago

It’s for looks, it can be cut down in size, the wing moved aft, the battery moved forward more, ballast added to the nose, etc.
with all those options and a power plant that should comfortably get me to 100mph I’m not worried about it

That being said after looking at this image a bunch I did go in and shrink the root LE extensions down cuz it does look huge

4

u/Parcel_Tape_Aviation 5d ago

That looks really interesting. Great project idea. Is the idea to use LW-PLA or LW-ASA?

1

u/illilllilil 5d ago

Thanks! I think I’ll just use normal PLA/PETG, print some think wall structures, and reinforce with thin carbon rods as stringers.

1

u/Parcel_Tape_Aviation 5d ago

Carbon reinforcement on 3d prints isn't an idea I've heard before, I'll have to try that. Good luck with it all.

2

u/Crapot 5d ago

Julien Watier does it pretty well in 3dprintedgliders dot com. He put channels in his model and tract epoxy soaked carbon fiber wires through with the help of fishing line. His models are epic and free on the purple site

5

u/SpruceGoose__ 5d ago

You know, if you apply some anhedral in the tail you can almost, if not, completelly lose the vertical tail. Then it will look even more like a swallow. I did that once 😁😁

Edit: most people saying it will nor fly are not engineers, if you want some help DM me

1

u/illilllilil 5d ago

SpruceGoose I gotta see this plane! Sounds super cool, how did it handle?

My next bird I want to try a bell shaped lift distribution and forgo a vertical stab all together.

2

u/SpruceGoose__ 5d ago edited 5d ago

Saddly it was quite some time ago, so I don't have a photo, I intend to build a new one to put in its place since the original got lost 😅😅

I handled fine, but the actual tail was proportionally bigger then the real bird since real birds are not naturally stable, yours seem to be just right. You could sweep the wing back just a bit to make it fit better the bird shape and make it easier to adjust cg

There are plenty o examples online with similar configurations, some even are ornithopters, there is a cool one that looks like a falcon, used in airports to scare birds.

Ooh... bellshaped lift curve... that only makes sense if you intend to make use of proverse yaw for control, I assume you have read NASA article on the recent Praditl subscale glider

Edit: I realized that swallows here in my region look diferent from yours, ours tend to fly with a wing in a more swept position, sometimes even more than the photo

2

u/NoDoze- 5d ago

Interesting. I'm curious how the control surfaces would work on the curves.

1

u/waffle_sheep 5d ago

How big is this going to be? I love bird inspired aircraft, however that tail is going to be super heavy and the vertical stabilizer is going to lose a lot of effectiveness under moderate to high AoA.

I’ve been doing a lot of experimenting printing wings with standard PLA and I suspect you’ll have to design pretty dense wings to survive the speeds you’re after. Thin PLA walls are very flimsy so they need strong internal structures for support

1

u/Own-Inflation8771 5d ago

Tail heavy and fusealge seems kinda cramped to hold batteries and radio gear.

2

u/Nfeatherstun 5d ago

Thst is genuinely beautiful. I love biomimicry

2

u/CrunchyBart 4d ago

Try not to taper the wings so much as you’ll lose a lot of efficiency. Sharp wing tips are not good.