NSL Takes Their Propeller Driven Car To The Drive Through


So what’s the first thing you do after completing your propeller driven land tricycle build? Head on over to the Starbucks drive through and see what kind of response you get from the workers. That’s exactly what the guys from North Street Labs did. You can see the response in the clip after the jump.

Having three wheels and being moved by an electric motor with a propeller led to the name TriFly. The build is their entry in The Deconstruction, a build contest which includes other entries like the Beer pouring machine we featured on Monday. Aside from the fun with the final project, NSL’s well-produced video includes a quick trip through the fabrication process. They did a great job making the machine about 40% street legal and it’s obvious they had a blast while doing so.

103 thoughts on “NSL Takes Their Propeller Driven Car To The Drive Through

    1. Oh yeah, it is a Rite of Passage, taking a stretch limo, or riding mower, farm implement, those have been done, new novelties must be found…
      But don’t try _walking_ through the drive through, you’ll be ridiculed and rejected DAMHIKT
      (Don’t Ask Me How I Know That!)

    1. Great idea, but we are currently sourcing an actual airplane propeller so we can use all the power of our motor at low RPMs, we figured with a bigger prop, a bunch of EMT conduit can be formed into a shroud, and a cage welded to it.

      We actually brought the stuff to shroud the prop, but we simply ran out of time in 48 hours.

  1. It’s hard to see any coolness in this project when there’s such a huge danger. I can live with projects that endanger the owner but taking that thing out in public. Extremely dangerous, especially for little kids that don’t know better.

    Seat belts, yeah sure, should probably have them but it’s not the end of the world in my opinion. But not having a cafe around that prop is just stupid.

          1. slowJim, stop trolling. You can see the connector going across the top of his right leg. It’s not like he was just balancing it there for fun. Never mind the fact that I watched him attach it.

  2. Give the man a break, he obviously didn’t have his coffee yet.

    Neat build, but some forethought should have gone into safety.
    I mean, we all do stupid things from time to time, but usually it doesn’t involve the potential risk of limbs.

  3. Actually the prop arc is kind of small, so sticking random body parts in it is not what most worries me. What most worries me is that it’s a wooden propeller, which have been known to splinter, and fracture and throw a sharp stake out at high velocity.

    In it’s intended use on a model aircraft this risk is dealt with by model clubs having flightline safety procedures, and the fact that most of the time, at full bore the nearest humans are going to be a good distance away from it. It is also going to be up in the air, and not subject to bits of road grit and small stones being flung at it by passing traffic, the highest risk of that on a model aircraft is on landing, when it will be throttled back, or on takeoff, where it would be going away from humans.

    If this contraption is only used to drive around fields and empty parking lots by the occupants the risk is small. If used within 50ft of innocent bystanders regularly, the risk becomes larger.

    1. So a ducted fan would actually be safer, as well as more efficient. Just wrap a cylinder around it and put screens on each end. Simple mod, more thrust and safer.

      (I really like the “cafe” typo…)

    2. RoadWarrior222, thanks for the detailed criticism, this is a lot more serious to us than all the other Danger Mongerers. I wanted to address that our prop tip speed is much lower than that of an RC plane using this prop because our motor tops out at 4100RPM with this battery pack setup. The prop is spinning at 195m/s compared to 340m/s for MACH 1, this means our tip speed is only 1/2 the speed of sound.

      Every time we start the prop check the hardware and propeller condition. At these speeds we have only had minor specs of the polyurethane coating chip away. Easy fixes and nothing deemed dangerous.

      People can hear this thing coming from THREE BLOCKS AWAY, if someone runs into it – That is a Darwin Award in itself.

      The ease of starting and stopping an electric motor allows us to turn it off when people are approaching.

      1. There are a lot of people dissing your build for safety reasons. But I am not one of them. I think this thing is awesome!

        Keep up the good work, and keep building.
        I love the three wheel configuration.

    3. Really? Wooden props pull/push thousands of aircraft through the air on a daily basis, wooden props are waaay lighter than metal ones. Besides, choosing a prop for an application is not a trivial thing. Just because it’s wooden doesn’t mean anything. A cage would have been a good idea. period.

      1. Pilotbuilder, we actually completely agree! We even have the metal! But didn’t manage to build it in the 48 hours allotted. Now that our demonstration video is submitted we are working towards this goal, as well as much more.

      2. Yes and airfields and most of the air, is large and empty. Props on aircraft are inspected on a daily basis and have to pass regulations and official safety approvals and inspections. The thing is, we’ve forgot most of the learning curve stuff that went with that pre 1930ish and in making bigger props for model aircraft or other applications, and may relearn the hard way.

        So, use an FAA approved aircraft prop inspected and maintained to FAA standards on a road vehicle and I won’t worry about it flying apart.

        Have a twin rotax homebuilt where the passenger sits in line with the plane of the prop and you broke one on landing yesterday and carved one out of a random lump of 4×6 overnight…. yah, I think I’ll pass on that joyride thanks.

        1. We are using Hobby propellers here, this isn’t even FAA category yet. But good idea, we already know their standards about routine airplane maintenance before flight (seriously we read everything we could find). We even had an aeronautical engineer in communication with us during the build.

          As far as us CNCing a bigger prop, we have done extensive research, no simple 4×6 can be used. Certain woods offer certain properties in different grain directions, etc,there are truly too may details to list here, we will do a large write up as soon as something gets designed and made. Not to mention if we make our own prop, we will not be using this without a massively strengthened shroud and a thick cage for our own protection.

  4. If I was working that drive-thru, I’d have dropped his lunch into the prop just to prove a point. The point being it’s not just themselves being aware of the prop that they should be worried about. Very irresponsible.

    1. Your “idea” of throwing stuff at the spinning prop is the kind of stuff that’ll cause people to get hurt.

      Also, you should know the girls in the Starbucks were aware – one of them helped us build it. Everyone around was aware of what was coming through, including the cops inside.

  5. You could use it as a Bassomatic where ya just toss the food into the prop for all those behind you to enjoy :)
    /Still want to build that vacuum cleaner car from the back of Boys Life lol

    1. Haha, yes GOOD EYE, Ryan helped us build, clean, and coffee us!

      Right now our top speed is only ~20 mph on smooth road, with two people it is nearly half.

      This is because we are running a prop designed for higher RPMs than our motor can output. at 4100 rpms we can acheive 83.03lbs of thrust (our top thrust), but at only 5700RPM we can get 160lbs of thrust! So we are currently trying to source, or CNC, a 48″ prop to better match the RPMs of our motor, and that will get us up to 250lbs of thrust (scary time)

      1. Steve also forgot to mention the fact that we are using enormous inefficient wheels. The rear drum brake is dragging too. Frankly, I’m surprised it goes as fast as it does. A few minor tweaks, and this thing will be crazy fast.

  6. I’m a thinking if you geared the prop down and used one the width of the vehicle, (with a shroud) you could park it faced into the wind with your brakes on and it might do something to keep the batteries topped up :-D or go the whole hog and put a fully swiveling power head on, with a tail to direct it into the wind, that you can unlock when you park.

  7. Steve,

    Don’t let the turkeys get ya down! As an aero engineer, I can tell you that it’s a whole lot easier to critique someone else’s design than it is to invent and build one yourself! Ya done good here. Just keep evolving the design, (including anything good from the “feedback,”) and someday you’ll own a company selling bunches of them. Google Tennessee Props for a decent wooden one, or IvoProp.com for adjustable pitch composite ones. Also consider a ducted fan, which can be more efficient.

    1. Prop atm. imho is least pf the issues on the design, whole frame is steel, that seems rather heavy, really wide small tires, that seems the opposite of good design. if they want to make just “something”, they achieved it. bot to the efficient cool design there is a long way.Btw, we have saying around here, “with engine and prop big enough everything will fly” – (about efficient designs)

      1. Bobby,

        We really agree with you, but considering the build started after all the metal suppliers closed for the weekend, we had no choice. We also had two broken golf carts donated to us by the local university, and very little money to spare. We set out to do something that many doubted would even work, using a small hobby R/C prop to propel people in the most inefficient form imaginable! But it worked, and it was fun.

  8. K, I’m shocked… The moment you took that POS out in public you demonstrated your mental worthlessness (do you guys have any common sense? I’d expect that old man would know better). You guys are idiots; kretins.

      1. Apologies, I was upset, but everyone should ridicule these people even more (so they won’t do something this irresponsible again). Maiming people is not cool, dude. Impaling people with wooden propeller fragments is not cool, dude. They took a risk on someone else’s life… is it even legal to drive that thing on a public street?

  9. jesus f christ. Prop cage. everyone has said it, and it can’t be said enough. First thing I thought of when i saw that pic at the start of the article,

    Secondly, yes, wooden props are used in massive numbers of light aircraft around the world. But, they are not used 18″ off the ground on unswept roads and streets for their entire lifetime. You will be getting prop strikes from gravel and small chunks of loose asphalt, not to mention stray litter.

    Ok, so it doesn’t crack the prop right there on the street. Where’d the rock go that hit the prop? Oh ya, on a semi-random trajectory at stupidly high speeds. What could possibly go wrong? You need a front grill on the prop, or you will put a dime sized rock through someone’s more interesting body parts at several hundred feet per second.

  10. I can’t understand how all these idiots have to say is “it was a 48hr build”!

    Use 1 of those hours to make the damn thing safe, seriously this cannot be said enough, If you are going to make something that is around others “play safe” not “retarded”. Yes this is name calling but they deserve it, I could go on about how they could have used a lighter frame or different wheels but no that doesn’t matter if this thing can take someone’s hand off.


  11. They say that the police were well aware that they were using this thing at the drive through and by extension I assume the police knew they’re using this on public roads. Would be great if we could file a complaint against the officers that let this happen.

  12. What is the Deconstruction? It is a game about re-thinking the world as we know it, taking it apart, making a few adjustments, then putting it back together a little awesomer-er. It’s a light-hearted competition, but it’s really more of a large-scale collaboration between friends, participants, and the public. The concept is to make the world a slightly better, more fun, and more interesting place over 48 hours.

    1. It really was a good time. We were used to having 72 hours to work with, so this one seemed way more fast paced. We borrowed our build site from Steve’s work. We had to drive out an hour away from the site just to make any essential CNC machine cuts. Then we had to clean up the whole build site, rest, film, and edit our final video by the next day. We REALLY wanted to go with a ducted fan setup because it dramatically increases static thrust (and safety), but we were working with inexpensive hobby RC parts with time constraints. It was also a “math” vs “gut” challenge. We had a LOT of doubters (assorted friends, family, and coworkers) who felt it wouldn’t work, and even I started to doubt myself until the first test… and man was that a relief. It’s also hilarious to feel gale force winds while traveling 20 mph.

  13. hi
    i really like your car, it was an very cool idea
    i want to build this propeller car as my college project, so the persons who build this car can help me in making this car again.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.