Four days, one garage, a 3-by-8-foot table twelve feet shorter than the airplane, and a Wednesday deadline: drive it three hours to Dayton so about a thousand people can try to knock it out of the sky. It has to come apart, fit in a truck, and weigh under 55 pounds. Eric had also never successfully skinned a wing in his life.
While this was being built in a garage with a hammer found on the side of the road, a hundred engineering teams, startups, defense contractors and universities were landing at Wright-Patterson Air Force Base for a $6.5 million DARPA competition — same weekend, same airfield. Different budgets, same 55-pound conversation.
The outer 6-foot wing sections bolt onto an 8-foot center section; assembled, the airplane does not fit in the building. One side already had a box joiner with top and bottom plates; the other side got the aluminum bars glued in and clamped, minus the wood plates, "and hope for the best." While that dried the motor pods got designed — a little cell that bolts straight to the spar — and cut on the laser as a skeleton, with a second pass where the first didn't quite cut through. Then three more.
Skinning is where a wing stops being a skeleton. Wrap a sheet of foam around the ribs and, if it bonds everywhere it is supposed to, the wing becomes dramatically stronger than the sum of its parts. The catch is "everywhere it is supposed to": the glue only works where the foam actually touches the ribs, and on a 20-foot wing every error is multiplied — a sixteenth of an inch is a gap you can see from across the room. A clamp reaches a few inches in from an edge; the middle of this wing is three feet from any edge. The answer was weights: every heavy object in the building, laid on top for two hours.
The 12-inch wheels came from foam board, because nothing you can buy is both big enough and light enough for a weight-limited airplane. What was needed was a lathe; what was available was an angle grinder and optimism. Hardpoints went in where the wing meets the fuselage — threaded inserts set into wood under the foam, the channel shaped with the Hot Wire Foam Factory battery hot knife and a bendable blade — because that joint is the only thing holding a 20-foot wing onto the airplane. By night the center wing was glued up and the outer-wing ribs were on, tacked with StyroGoo so nothing needed clamping.
Other work could not move, so the plane got far less than planned. The OMTech Maker 2028 kept running beside it, nesting a whole batch of motor-pod parts in one job on the big bed — the reason a machine like that earned its place in the shop.
With one day left, all three wing sections went together for the first time and the problem was immediate: the spacing of the outer wings' joiner tubes was wider than the center section's, and the joint buckled. That became future Eric's problem, because the motor pods had to go on now — each bolted directly to the spar, which was buried under the skin that had just taken two days. Four holes cut into a finished wing, hoping to find the mounting points underneath without destroying the work. Four propellers on one wing pass with about an inch between tips; one crooked pod or a spacing error and they would hit on the first throttle-up. The math was right. They cleared.
Then the weight budget. The airplane already weighed 52.6 pounds; four separate batteries would add another six. Wiring the motors together in pairs runs the whole plane on two batteries and saves about three pounds. That solves it on paper; whether the wiring can reliably power four motors would only show up with the airplane running.
The fit problem got fixed by pulling the middle ribs inward and bracing them with wood to hold the tubes at the right spacing, then sanding the rear spar until the skin could sit flush. Each 6-foot outer wing was skinned in two stages — glue the bottom, test the fit, only then seal the top — because with the top open there was still a way to adjust the tubes, and once it was glued down there was not. One wing finished late at night; the whole process repeated on the other, with a 3D-printed tip for the glue bottle arriving, naturally, on the last section. By the time the second wing was under weights, that was all that could be done.
Departure morning: everything not finished in the shop, with the laser, would take twice as long at the field. Lifting the weights off the last wing, a motor mount broke. Before the airplane ever left the shop it already needed a repair, which confirmed the thing Eric had been trying not to think about: this was not transporting a finished airplane, it was relocating the rest of the build. Spare parts got cut for whatever seemed most likely to break next, plus one part that contributes nothing to flight — a sign explaining what the thing is. Tools, spare materials, and the Bambu Lab H2D (a printer that can also laser-cut, so a forgotten or broken part could be made at the field) all went in the truck around the plane. The elevator almost got left behind. Then: off to Flite Fest 2026.
Disclosure: OMTech provided the laser cutter; Hot Wire Foam Factory provided the hot knife and StyroGoo. OMTech, Bambu Lab and Hot Wire Foam Factory links are affiliate links.
| OMTech Maker AF2028-80 CO₂ laser · sponsor-provided | Cut every motor pod and rib in this episode; the large bed nests a whole batch in one job. The OMTech lasers ranked for RC work · code ERICROBBRC for 5% off · what a laser can cut. |
| Bambu Lab H2D | Came to Flite Fest in the truck as the field workshop — printer and laser cutter for parts forgotten or broken. Printers and materials · which printer for RC. |
| Hot Wire Foam Factory hot knife & StyroGoo · sponsor-provided | The battery hot knife with a bendable blade shaped the hardpoint channels; StyroGoo tacked the outer-wing ribs without clamps. Foam tools and adhesives. |
Auto-transcribed from the video, so expect the odd mis-heard word. Here so you can search or skim what was said without watching.
Look at this massive airplane. Well, that's not good. How much of a 20-ft airplane can you build in just 4 days? Cuz that's what I've got. 4 days, one garage, and a table that's 3-ft by 8-ft, which is about 12-ft shorter than the airplane. But, here's the catch. It has to come apart. It has to fit into a truck, and it has to weigh under 55 lb because on Wednesday, I'm driving it 3 hours away to Dayton, Ohio, where about 1,000 people are going to try to knock it out of the sky. I have also never successfully skinned a wing before in my life. Bad idea or bad idea? What are the odds of it working here? Okay, this is crunch time. I recruited my brother. He's helping here. Let's get to work. First, we got to finish up our wing spars. Uh what are wing spars? Oh, glad you
asked. So, wing spars are actually what holds the structure of the wing together. So, the other side we did a box joiner. We put the top and the bottom on. This side, we're just going to glue this in and hope for the best. A lot of hoping for the best. Yeah. The outer 6-ft wing sections bolt onto a center section that's 8-ft wide. Add it up, and you get an airplane that does not fit in this building. Because it would suck if this failed cuz taking this apart would not be fun. It'd basically be rebuilding. Clamps, clamps, clamps. Okay, we got our aluminum bars clamped in place. Hopefully, that's going to be strong enough cuz we did not put our wood plates. Now, since this needs to dry, I just designed up this little motor in a cell for our motor to attach to there, and then this will screw straight to the spar. Go over here on
the laser. You can see it's cutting away. That sucks. It didn't cut through all the way. Do another pass. If it didn't cut through this time, then it's So, here's our motor pod that we made. We got our little like It's not glued together yet. Um but, it's like a skeleton design, so hopefully it's super strong. I guess let's make three more and actually glue them together. Good morning, everyone. We've got a ton of work get done today, so let's jump straight into getting these motor pods all glued up. And if you aren't subscribed already, you know what to do.
Let's get to it. As I'm building this, 100 engineering teams, startups, defense contractors, universities are landing at Wright-Patterson Air Force Base for a $6.5 million DARPA competition. Their aircraft has to weigh 155 lb. Same weekend, same airfield, same 55 lb. I FOUND THIS HAMMER ON THE SIDE OF THE ROAD. I think it works pretty good. Thanks for whoever dropped it. And here I am building a 20-ft airplane in a garage with a hammer I found on the side of the road. We've never really successfully skinned the wing. Successfully. Skinning is where a wing stops being a
skeleton. You wrap a sheet of foam around the ribs, and if it bonds everywhere it's supposed to, the wing gets dramatically stronger than the sum of its parts. So, that's the key. If it bonds everywhere it's supposed to. Getting that contact everywhere is the whole problem. I don't know about this whole skin thing here, but we're trying our best. See how it works. The glue only works where the foam actually touches the ribs. And there's a lot of wing here for it to not touch. Every error gets multiplied by 20 ft. A 16th of an inch is a gap you can see from across the room. Normally, you'd clamp this, but a clamp only reaches a few inches in from the edge. In the middle of this wing, it's 3 ft from any
edge. Okay, how are we going to clamp this? Weights. So, the answer is weights. Every heavy object in the building laid on top of it for 2 hours. Just we're just taking a little bit off. Yeah, just And just like kind of cleaning it up a little bit. How fast? Slow as you can. That might do it as long as it Go faster. Just try to go to consistent speed. This guy is going to owe me a dollar now. And while the wing dries, I can't touch it. So, wheels. I need 12-in ones and nothing you can buy is both big and light enough to be worth putting on a weight-limited airplane.
So, we can make them out of foam board. They're round or just not the right shape tires yet. But at this pace, I don't know if we're making them look more or less like tires. [clears throat] And at this point, we don't know what
we're doing. What we needed was a lathe. What we had was an angle grinder and optimism. We've got half of the wing glued up here. We've got that side completely done. This side, the bottom is glued on. We just got to wrap the top around it, as you can see, like that. And that'll complete our airfoil. And I think this wing's actually turning out really good so far. Laser cutter's been doing fantastic. We got some ovals going on here.
Oh, these weren't helpful? And while we continue to let the wing dry, we need to get the wing ready to bolt to the airplane. We need to add hard points where the wing meets the fuselage cuz that's the only thing holding a 20-ft wing onto the airplane. So, I'm setting threaded inserts into the wood and setting that underneath of the foam. This is the battery-powered industrial hot knife from Hot Wire Foam Factory and I've got a bendable blade in it right now so I can actually shape the channel that I'm cutting out to the perfect size. If you want a new tool in your shop, check out the link in the description below. And just like that, the center wing is all glued up. You see that right there? Hello. But before we can call it a night, we have just one more job to do. We need to
get all the ribs glued onto the outer wing section so we can have it ready to skin tomorrow. I'm using the Styro Glue to glue all these ribs on and because of its instant tack feature, I don't have to clamp all of this in place, which makes it super nice to be able to do this super fast cuz we don't got a lot of time left. We've only got 2 days left before I leave for Flight Fest. So, we are officially in crunch time. There's still a ridiculous amount of work to do left, but unfortunately, I had other work today that I couldn't simply move. That meant I didn't get as nearly as much done on the airplane as I wanted
to, but while I handled everything else, I was still able to keep my OMTech Maker 2028 running beside me cutting out all the parts for these motor pods. And honestly, this is exactly why having a machine like this is so useful. Whether you're building a giant RC airplane, making props, signs, engraving tumblers, or working on something completely different, the possibilities are nearly endless. This 90-W CO2 laser can cut through thick materials including clear acrylic, but one of my favorite things about this machine is its large cutting bed. Instead of splitting these ribs up into a bunch of smaller jobs, I can nest the entire batch together and cut them all at once. The OMTech makes some fantastic machines. They have options for almost every kind of maker from compact 45-W desktop lasers all the
way up to 150-W production machines. If you want to check them out, use the link in the description and enter code Eric Robb RC at checkout to save 5%. Any purchase made using my code also supports my channel and makes crazy projects like this possible. Thank you guys for supporting me in that way and thank you to Om Tech for being such a great partner. I don't know what I'm going to do. I'm going to get a flight test and not have my laser cutter. I'm genuinely going to miss it so much. With one day remaining until I leave for flight test, I'm finally ready to assemble all three wing sections together to see what it looks like. And I quickly realized we have a major problem. Well, that's not good. So, I just attached this wing here and I noticed the spacing on the outer two wings is larger than the spacing on the inner
wing. So, when it connects, it's making this all buckle. Did I mention I'm not a professional and never done this before? But that's going to be a problem for future me cuz I need to get these motor pods and motors mounted right now. So, let's see if we can cut open the wing and get them installed on the plane. Because each pod needs to be bolted directly to this spar. But the spar was now buried deep underneath the skin I just spent two days installing. Is that long enough? There was no way around it. I had to cut four holes into the finished wing and hope I could find the mounting points underneath without destroying what I had just built. Getting the pods mounted was only half the problem though. With four propellers on one wing, the tips pass with about an inch between each other. If one pod was slightly crooked or my spacing was wrong, the propellers could hit each other during the first throttle
up. That's what I wanted to see right there. My math is correct. Okay, so now we've got this soldered on this side. We've got ESCs on your motors mounted. I've got the wiring all tucked in. This will go to the battery which is right underneath of here. And somehow they cleared, but getting the motors mounted created another problem. Powering them without destroying my weight budget. The airplane already weighed 52.6 lb and with four separate batteries would add another 6 lb. By wiring the motors together in pairs, I could run the entire plane on two batteries instead of four, saving about 3 lb. And that solved the problem on paper. Whether the wiring could reliably power the four motors was something I wouldn't know until the airplane was running.
There it is right there. All the motor pods are on. I think they'll be super solid here. Dude, this thing's so cool. The motors were mounted, but the airplane still wasn't structurally finished. Both outer wings were only skeletons, and without their skins, they were not going to be able to fly. The last time we tried putting the wing together, the aluminum tubes would not slide into the center section. They were slightly too far apart, and once we add the skins, the spacing will be locked in permanently. So, to try and fix that, we pulled the middle ribs inwards and temporarily braced them with wood to hold the tubes at the right spacing. But, let's slide it in and see if that actually worked. Got to pick it up slightly.
Pretty close. You see these pink like spacers there? Think that could go. With the tube spacing corrected, we still had to sand the rear spar until the skin could sit completely flush. Any gap here would keep the skin from bonding properly. We were skinning each 6-ft wings in two stages. Glue the bottom first, test the fit, and only then seal the top. We're deciding whether it's better to have the wing stuck on there and we can't get it off, build it separate and
then we can't get it on. Because this was the important part. With the top still open, we could still make another adjustment if the tubes were wrong. Once the top skin was glued down, there was no easy way back in. Now, I can be like working late into the nights. It's dark outside. One wing section was finished, but we couldn't stop there for the night. We had to repeat that entire process on the other 6-ft wing section.
It's dripping. It's dripping. It's dripping. And we finally got smart and 3D printed a tip for this glue. Of course, it was on the last section. Yeah, we're waiting down. I got to tell them. We got to tell the people. Tell them we're waiting. We're waiting. Yep. Now, we just wait. It's glue all over my hand. Yeah. So, if any of you want to build a 20-ft airplane on a 3-ft by 8-ft table, it is possible. Just wanted to let you know. Yep. It's all I got. Let's do this. Get that. Manly energy.
By the time we got the second wing under weight, that was all we could get done. Everything else had to wait until departure morning. Good Wednesday morning, everyone. We're trying to get this wing finished up cuz everything I don't finish up here where I have space to do it in the laser cutter, it's going to take me twice as long to do while I'm at Flight Test. Last night, we got that wing skinned. We got that outer wing skinned. So, I just got to take all that weight off of there. This center wing is looking great. These are pretty heavy.
My foot. Well, that's not good. The motor mount broke. Hopefully I don't have to be worried about the reliability of those in the future. Before the airplane even left the shop, the airplane already needed a repair. That confirmed what I had already been trying to not think about. I wasn't transporting a finished airplane. I was relocating the rest of the build. And after doing some last-minute soldering and final touch-ups, I think we're ready to go. We've got the laser cutter going. I've got some final touch-ups done on the wing. I think I'm going to get the truck. We're going to load it up. We're going to get it headed off to Flight Fest. There was no way to know
what would break next. So, I cut back up to the parts I thought we were going to most likely need. I also made one part that contributed almost nothing to getting the airplane airborn. A sign explaining what this thing was, cuz if we actually got it assembled, people were going to have some questions. The only problem was, how do you pack for problems you haven't discovered yet? The answer was bring enough tools, spare materials, and equipment that hopefully solve whatever came up. I got most of the tools loaded up in there. Now, we just got to grab the plane, stick it in there. Hopefully we'll have enough room.
And of course I was taking my Bambu Lab X2 D. It's both a 3D printer and a laser cutter, which meant if I forgot a part or broke one, I could manufacture another one at Flight Fest. It took up a lot of valuable space, but leaving it behind would have been a terrible game. Packing everything else up, I almost the elevator. You better get that packed in there. We are off to Flight Fest 2026. Wish me luck, and I'll see you guys in the next one.
