New user looking for advice on getting into the hobby and scratch-building planes

[anaximander]

Hi all! I'm anaximander, and I'm hoping the folks here can give me some pointers on a project of mine.

I've always been interested in RC aircraft, and I've been interested in building a UAV ever since I nearly got the chance to do it for a uni project, back when ArduPilot was still very new and something you ran on an actual Arduino Mega. Now, a fair few years later, I've decided I want to take the plunge and start flying. I have a 3D printer, a rough understanding of the principles of flight and the basics of airframe design, and a background in engineering and software development. Ultimately, I'd like to design my own aircraft, 3D print it, and set it up to fly autonomously and do aerial photography. I realise that's quite ambitious, though, so I may have to start a little smaller.

I figure step one is to get something that flies, and learn to fly it. I was hoping someone could help me make sense of all the parts of the hobby that I know less about. I feel like I know enough to assess an airframe, but I don't really know where to start from an RC point of view. I know I'll need a transmitter, and I know these vary wildly in cost and capabilities. Is it worth going straight for something that can do all the things I'll want later, or should I start cheap and upgrade later? I know that my eventual goal is to build a flying wing - should I start out learning to fly on a more conventional airframe, or do wings fly differently enough that I should try to find a flying wing design to learn on? I have a 3D printer and I'm not afraid of a little self-assembly; are there any good 3D-printable designs that I could practice with? I'm pretty sure the process of learning to fly will involve a few crashes, and I like the idea of being able to print replacement parts to repair crash damage, rather than feeling like I just destroyed an aircraft I spent good money on.

Here's hoping someone can help, and that someday I'll have some cool things to share.

 

[sundown57]

I have tried over and over to 3d print an entire plane. The problem is they are much too heavy. Speed does help some, If you have a heavy plane you might get it airborne but you would need to keep the speed up to keep it airborne.

 

[Vimana89]

The type of foam we use is generally pretty cheap and light(Dollar Store foam board anyway, Depron and stuff's a bit more), so fabricating new parts or a new airframe is cheap enough. Most people that involve 3d printing only use it on select components of the airframe and build mainly with either foam board or other more sophisticated foam like Depron and some other hobby grade types like EPP, EPO, etc.

I have not even gotten into CAD, 3d modeling or printing, or any of that jazz yet(a lot of members are really good with that stuff though), I've been in the hobby since late 2018 just with a straight edge and pencil doing custom designs and scratch builds. I have no background in engineering or aerodynamics, but the hobby has taught me quite a lot about aerodynamics and air frame design.

As far as flying wings, they are a hair less beginner friendly than your standard trainer, but if your goal is to mainly or exclusively fly them, then I'd start with one. There are some more docile and easy-going wings out there. You might want to try a simulator, even one that just uses a keyboard to fly, that offers a variety of planes, so you can get a feel for the characteristics of a flying wing and how it compares and contrasts to other stuff.

Most basic flying wings are 3ch with just throttle and elevons, and maybe it may or may not be best to start with one of these, but to get the full capabilities and performance I'd personally say you want a 4ch that can yaw, be it with rudders or twin engines and thrust differential.

Maybe check out some tutorials or vids on basics to know what you'll need, but it's really pretty simple in terms of electronics.
You'll need a transmitter, receiver, Electronic Speed Controller(ESC), your motors(s), battery, and your servo motors that operate your control surfaces, and the other parts that corelate to the servos(push rods, control horns). You may need servo extensions or other extension cables depending on your parts placement and how far certain stuff is in relation to other parts.

That's the gist of it, if you have more specific questions there's a ton of people here with a wealth of knowledge willing to help.

 

[anaximander]

I've seen a number of successful 3D printed aircraft (for example

and others by the same designers) but I'm having trouble deciding whether any of them would be a good airframe for me to learn to fly with.

 

[JasonK]

Are 3D printed planes interesting? yes
Are 3D printed planes the best performance option? maybe... but I don't think so, as I don't see racers, long distance, etc wing flyers 3D printing and if they were the best, I would expect them to take over those situations.
Are 3D printed planes a good choice to learn on? no... having to reprint a plane for every learning mistake would be lots of filament/time/etc. They also need to go faster (which means less time between turns and worse crashes).

 

[JasonK]

If you want something to learn on, there are multiple FT wing designs. I have flown the Dart and it flew very nice (until one of my props came off its motor mount and ripped the wire right out of the motor). The F-22 (which doesn't look like a wing at first glace, but is one by controls) is even easier to fly and almost all the crash damage ends up on the nose which can be cut off and rebuild fairly easy. I tried building an Arrow, but couldn't get my CG quite right and haven't tried again recently.

 

[Vimana89]

Are 3D printed planes interesting? yes
Are 3D printed planes the best performance option? maybe... but I don't think so, as I don't see racers, long distance, etc wing flyers 3D printing and if they were the best, I would expect them to take over those situations.
Are 3D printed planes a good choice to learn on? no... having to reprint a plane for every learning mistake would be lots of filament/time/etc. They also need to go faster (which means less time between turns and worse crashes).

This about sums it up. Could you build a successful 3d printed plane eventually? Yeah, I suppose you could. It's just not a very practical option to learn on and also tend to be a bit heavier, which could make a long range/long duration UAV a little less efficient than it could be from mainly foam.

 

[anaximander]

Ok, so this is more or less in line with what I was thinking. I'd tried to estimate some figures for structural mass coefficients of various materials, and while those figures were very fuzzy, 3D printed was not coming out on top (at least in regular PLA; the foaming LW-PLA is a fascinating idea). My interest in it was mostly from the viewpoint of strength, the fact that I already have it on hand, and the ability to produce any shape I can imagine (and model in CAD). For those reasons it's still an attractive option for certain parts of the aircraft, but I had also been thinking of ways to reduce weight.

For that, I was always going to end up looking at foam, either in solid form or as foamboard. Board is probably easier for me to source and to work with, so I think my best bet is probably a foamboard shell, using internal structure that is either made of more foam, or 3D printed, depending on what characteristics I'm after. In places I might look at other things (PLA softens if it gets too warm, so the motor mount may have to be plywood or something). I think I've ruled out heatshrink film; it's super light, so I may keep it in mind if I really need to shave off some weight, but it's also more expensive and more fragile, which is not a great combo.

For the electronics, my rough plan was to find a middle-of-the-road motor and ESC, something I can use with a few different props as needed, and then as I move from kits to modifications to self-designed airframes, I can just move the existing electronics over. The temptation is to keep the first one as cheap as possible, but I suspect that would come back to bite me when I then have to upgrade fairly soon. A similar principle goes for the transmitter; wings and a lot of trainers can be flown on 3 or 4 channels, but if I'm thinking of adding pan/tilt cameras and more advanced flight controllers then I'll need more channels to control those, so perhaps it might be better to get a more capable transmitter up front?

 

[dahacker]

You are focusing on designing and building the end goal plane from the start, or thinking that you will be able to use a cheap plane's part in your dream plane. That is going to have you end up with a pile of broken plane parts and wasted money and you will quickly exit the hobby and just get a DJI Mavic Mini that will take more beautiful aerial video and photos than you will ever build from scratch.

I'm an Engineer too. Don't overthink this. Just build a simple foam FT plane like the Tiny Trainer with power pack A from the start. Learn to build it, learn to fly it. THEN start thinking about what you want to do next based on all the lessons you will learn. As far as what transmitter, charger, batteries, receivers, tools you need for your first trainer plane build, those are the right questions. Most likely all of that "stuff" won't be used in your dream plane.

 

[anaximander]

You are focusing on designing and building the end goal plane from the start, or thinking that you will be able to use a cheap plane's part in your dream plane.

Oh, trust me, I'm doing neither of those things. This will be a long road and I have many questions. This discussion has touched on both where I am now and where I want to end up, but please don't assume that I think those two things are that close together or have all that much in common. When I talk about reusing parts, I mean moving things from my first-ever plane to my second, and maybe my third, but definitely not just buying one set of parts and using them forever. As an engineer I'm fully aware that won't work. I know the ESC and motor from my first ever aircraft won't be the one in the big flying wing I want to build, because the first aircraft will be way lighter, so the motor won't have the power. Likewise, the batteries obviously won't carry over, because the wing is aimed at long endurance, and a small trainer won't lift a battery that heavy. What I am saying, though, is that I'd rather buy a set of stuff that will work for the first three or four planes along my route to that end goal, rather than something I'll outgrow rapidly.

The FT Tiny Trainer is exactly the sort of scale I was thinking for something to learn on - wingspan of 0.5m to 1m, simple controls, nice and stable, and light enough to bounce a bit if (or when) I plow it into the grass. Getting something like that was always the plan - but I was also looking at what I'd be getting after it. The FT kit planes are designed around a few common power packs, which is exactly the mentality I was after: get comfortable with one plane, then grab the plans for something a little less tame, move the electronics over, and move up. Or, in my case, maybe try printing part or all of the plane, put the electronics in that, and see how it compares.

The transmitter is the one part where I probably would look a little further ahead. Even the "cheap" radios aren't all that cheap, and there's no risk of breaking a transmitter in a crash, so I don't see why I wouldn't get a transmitter that will last.

 

[dahacker]

Since you are brand new, I'd heavily recommend to stop worrying about the 2nd, 3rd, 4th plane. Or 3D printing anything for the most part. I've had an excellent 3D printer for four years now in heavy use, and I wouldn't dream of using it to make any part of an RC plane other than a tiny servo horn or something.

Also, the dream of moving electronics from one foam plane to the other generally isn't worth it unless you destroy the originating plane. You'll find that after you've spent a week building something and it flies well, you won't want to dismantle it just to save $80 in parts. This is why people usually have entire collections of planes. These are the lessons that will become apparent when you build your first plane.

One last piece of advice....don't build ANYTHING with landing gear.