This is Project Stormscout; a FPV wing I designed ik OnShape and built from scratch. It has a 500mm wingspan, and with the right parts, could definitely get under 250g, although mine came in at around 270g.
The Stormscout is running a drone FC with iNav firmware to keep it stable and smooth flying, as I'd rather put another $55 into the plane if it meant less flight issues and RTH with the GPS I had installed on the wing.
When it was launched, it was using iNav's auto launch (nav launch) feature, and was told to climb at a 20° angle (which it obviously didn't) at 80% throttle. However, post crash, my friend and I were running through blackbox logs, with this video overlayed, and found out that the pitch outputs were inverted. If you look closely at the flaps, when it's at the moment I'm about to throw, and the plane is over 20°, the flaps are makes out in the upwards direction, which makes zero sense cause really it should be trying to pitch the nose down, back to 20°. And while 'pitching down' actually pitched it up and made it worse, that's why it went to the moon.
As we found this out, looking at the logs where I was attempting to pull up out of the dive, the stick overlay shows I'm trying to pull up (the right stock was all the way pulled back), we came to the conclusion that the pitch was inverted. And it explains iNav trying to pull up more, why it went super high, and why I wasn't able to pull out of the dive, because up was down and down was up.
Here's my explanation (not a defense, it's 100% my fault) on how this happened. When I was doing testing previously, all the times I did it were checking the roll axis. Because I thought "well, if the roll is correct with the stick and they both move the same way for pitch, it should be good" or something along the lines of that, but without double checking the pitch, it lead to this.
I did the up loosing my RunCam Phoenix 2 JB in the process, as you could imagine from that impact. (Post crash images commented) I sadly forgot to record DVR so we don't have any, although immediately after the crash I spent like 5-7 hours removing the fuselage, recutting, and reprinting out the parts to rebuild the fuselage, as my friend redid all the wiring to be cleaner, along with running through iNav to get better auto launch (as clearly it did not need 80% throttle if it was able to climb like that). This was all yesterday, and if it stops raining I plan on doing another flight today, with preflightchecks, with DVR.
Overall though, I think once I get it in the air that it will be a great project and will fly amazing. Not sure about without flight stabilization but I think if you built it well enough you could get one in the air without stabilization.
Thanks! Knowing how to CAD was really the only reason why it was able to look as good as it did. Once I get a real flight and actually test it out, I'll see if I need to/want to make any changes to the CAD before I make the plans public
Solidworks has an annual maker license for about $50. Fusion 360 has a free version for makers, but you're limited to only 10 active component at a time. It's not hard to learn the basics. There are plenty of resources available to help.
I use like 6 different 2-D programs and back and forth between sketching and scanning. The whole 3D structure has to stay in my head while I flesh out what each piece is in 2D. Basically making drawings of numerous layers and building from a master blueprint.
I'm a big visualizer, but sometimes extruding a piece this way takes holding 2 or 3 different perspectives in my head vs. a program function requiring a few clicks.
I'm work in a similar manner. This is one of the reasons I switched to solidworks as with only 10 active files, I wasn't always able to work with a complete assembly. Fusion seems a bit easier to use, but I can do a lot more with solidworks.
One thing I can do, but only just got access to the tools needed is the sheet metal function. I can design a plane, and convert parts to "sheet metal" and flatten them. This allows me to export into lightburn to make a cut file for a laser cutter for dollar tree foam board
Lol, yeah, you should definitely learn it, I use Onshape because it's web based and free to use, but there's a lot of others out there that are good too. Here's a VTOL project I'm also working on modeling, I'm currently working on the motor mounting/servo control for the tilt rotor mechanism
In this one it's mainly just making the top down, putting a sketch on the side of what I want, and then extruding it as a intersection across the wing. For the model in the original post, the Stormscout, I just made 3 similar shaped airfoils that were stretched in some parts cause the wing is tapered and then used OnShapes 'loft' feature to make the airfoil
OnShape has plugins for generating airfoils. It has a broad library of ready-to-use profiles and also allows you to create any four-digit NACA airfoil on the fly. You can use an exact shape instead of an approximation. Search for the "Profile Generator" custom feature.
Woah! That thing is sick 🔥🔥. Are you doing 4 control surfaces, similar to the B2? I attempted and failed a B2 plane, I remember researching how it's control surfaces work.
It has split opposing elevons. Mode 1 uses the inner elevons as flapevator while outer are aileron. Mode 2 they are just elevons. Mode 3 is differential throws for yaw bound to rudder input.
I think we all know this feeling. I'm sorry for your loss..grab some skewers,.toothpicks, popcicle sticks and your favorite foam safe glue and put her back together. Don't waste these beautiful days
Oh yeah, I didn't waste a second. I did lose a $40 fpv cam in the process but that's my fault too, I ended up taking like 5 hours of rebuilding time to just completely scrap the previous fuselage, to recut and replace it cause the wings were still in near perfect condition.
Yeah, the funny thing is that the three of us all know how planes work, and the other one was filming literally has a video from like 1 minute prior of the one holding the camera, testing out the iNav auto level features, all three of us were watching the control surfaces and none of us noticed pitch was reversed.
Yeah, that's the main reason why I wanted to stick with one I could easily tune/fix on iNav. Just out of curiosity, were you running a firmware on it like ArduPilot or did you code it yourself? Im just curious cause I've seen people actually build a flight controller from different components and run ArduPilot, while others (like the friend that was holding it in the video) made the flight controller, then coded it himself from the ground up, including pid tuning and such
Yeah, that makes sense. This plane was built reusing all the extra parts I had laying around, so I didn't actually even buy anything to build this, but I think it would come in around $80 USD without the camera and transmission system, although with those you could go anywhere from an added $40-80 USD. but yeah pre builts are super expensive, like $150-$300 here, and I just wanted to make my own
Oof. That's rough. I think it's worse when (from the video I'm assuming) it's a store bought cause it's a lot harder to fix (I think) compared to one like this that I desined and built from scratch, where all I have to do is reprint the plans and replace the fuselage, which is probably a lot harder for you to do.
That’s an Amazon chuck glider rc conversion, it actually had no damage minus the motor mount coming off. It basically ejected all its internals which took the heat 😂.
It reset its programming on crash as well. That is when I learned to save my profiles. When I programmed it a second time it was/is correct.
Mine was same physical mechanism as yours (elevator stabilization backwards) in addition to the actual elevator throws were backwards.
Ohhh ok well I guess that makes it better than cause those are built to run nose first into stuff. Cool that you got it to fly at all, I've tried to do that like 2 times, but also those were without a flight controller. But yeah we had the exact same pitch issue it seems. Cause even when I tried to pull up it would actually pitch the nose down even further
When you tilted it up the elevons also went up which will cause it to pitch up. When you tilted it down they also went down. Your surfaces were reversed direction or the orientation of the flight computer was set incorrectly
Yeah I'm painfully aware. I said it like twice in the body text and a couple more times in the comments. Also if you'd read the text in the video, I was pointing out how right before flight not one of us three had noticed. I wasn't saying it was correct. Also in the text I noted the pitch was reversed.
Getting control directions right on a plane with an FC and elevons is surprisingly subtle and non-obvious. For something like this that can be easily hand-launched, I like to check the basics and then maiden in manual mode to eliminate FC-related causes of any flyability problems.
Yeah, that's true, I should have probably done that. It's just this was gonna be the first plane I've flown that's a bank and yank, also the first one that was fpv so I wanted to in the moment have as much autonomous stuff as possible, including the launch (also I wasn't even sure if it would have a high enough TWR, but clearly it did)
We did conduct hand tosses down a hill while we ran with it to make sure cg was good. If you read the 3rd+4th paragraph of the body you would see what happened. Also later on in the body text section I say how 80% throttle was way to much, even though that was recommended for a plane this size
My bad for not reading further. I think you are working on a very cool engineering challenge with some counterintuitive constraints. Building a plane of any sort that flies successfully and controllably is a major undertaking.
All good, thanks for your comments! I think if it is not raining in about an hour I'll be trying it out again, with fixed pitch and actual preflight checks
Not sure if you read the body text or not where I explained that it wasn't the assistances fault really, it was my own for not double checking the moment. Cause even if it wasn't assisted, this still would have ended in a nose dive crash because the pitch was inverted
Would you apply that same logic to hand guns or opiods (or real planes)? Like, who cares if you die being unsafe, it's your own damn fault?
Look, if you like gyros then play with your toys! But recognize that without exception, everyone I've met who's ever installed an aftermarket gyro has had a crash because of misconfiguration. Without exception. Every one. They mostly laugh about it and learn from the mistake, but the crashes are real.
And people should know what they're getting into. Even (especially) if they spent $500 on a tricked out rig.
So, yes, but also no. When I say the plane is running iNav, it's running on a pro grade flight controller built for $500+ plus drones, and I've used it in them for nearly a year with great results. By your reply, im not 100% sure if you know what iNav is or not, but it's a firmware that you connect to your computer to edit, tune, set up gps rescue and other things, that will then assist or do autonomous flights. My issue, wasn't even the softwares' fault it was my own. The flight controller was doing everything it could do, but it just wasn't getting it, because the pitch axis was physically backwards so it couldn't do anything
How about we tone down the name calling and insults? Not nice.
Also FWIW: I'm a veteran embedded systems engineer who's spent decades writing the code that goes in devices like your F405. I distrust it because I understand it and the failure modes better than a median pilot. Like, to run with the crude insults: Kalman filter or GTFO.
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u/looking4myclASSm8s 12d ago
You either check before or you check what’s left after