The Radius T-T Velomobile

The Radius T-T Velomobile human powered vehicle


Over the past year, [Dave] has been hard at work on his human powered vehicle. One year and six hundred hours of build time later, the Radius T-T Velomobile is complete. This 80 lb. vehicle features a custom body, mirrors, and integrated lights.

The Radius T-T started out as a TerraTrike recumbent tricycle. [Dave] built the body by laying up fiber glass on a foam mold. To that he added a variety of 3D printed accessories such as lights and mirrors. Inside the cockpit, the driver can control turn signals and flashers.

[Dave]’s blog provides a massive amount of documentation on the build. Everything from 3D modelling of the vehicle in Blender to the rear view mirror design is discussed. This great looking build should move along quickly with its lightweight design, but we’re still waiting to hear how fast it goes. Either way, it should be a fun mode of transport which will definitely turn some heads.

22 thoughts on “The Radius T-T Velomobile

    1. The good part is the guy documented his build well.

      If you’ve submitted some well documented builds, good for you, keep it up, if you haven’t maybe you should? Until then you could avoid trolling and offer constructive criticism, you know, like actually suggesting something that would have made it better?

  1. So guy adds 45lbs of unnecessary weight to what was an efficient form of human powered transportation, and it gets featured on HaD?

    Am I missing something here?

    1. ‘efficient form’ that’s arguable, at low speed the extra weight makes acceleration an issue so these things aren’t as good in the cities, but at high speed the aerodynamics of a well designed velomobile should allow it to go faster with less effort. That and any decent project write up probably deserves to be here

      1. I agree with you in principle, but to overcome the weight alone (80lbs overall), you would have to make a power efficiency dividend of 15% according to my napkin calculations, over the bare trike (35lbs). The catch is you have to make that gain at all speeds for it to be worthwhile; drag is the square of velocity, when you’re going up a couple of percent grade not at speed, 15% reduction in power input, made up in drag alone is going to be nigh on impossible to achieve, meanwhile you’re lugging 45lbs of deadweight.

        So, you know, it’s great if you can cruise at 45kph on a 0% grade at all times, but the real world isn’t really like that.

        tl;dr iron-on film over foam ribs and stringers is a heckuva lot lighter than the equivalent amount of fibreglass.

        1. I would have used 2/3 ply of pre-preg carbon as a skin with some very lightweight supports, it would weigh nothing! some of the body panels we made for our formula student car (with little to no tooling cost) weighed about 200g

    2. Yes, you are missing something – with a full canopy you can go with one of these outside even when it’s raining and not get wet. Include an electric power assist (or full electric) and you have a nice machine to get you to work and back any day wihtout getting sweaty, dirty or wet.

      Of course, like everything in life, it also has its disadvantages – added weight, its low profile makes it less visible to the guy in a car behind you, etc. The added weight is not that much of an issue in a recumbent as it would be in a regular bike.

      So, that, plus the cool factor and it’s good enough for me to own one. The problem is that ready-made ones are insanely expensive and I don’t have the time and a garage like this guy to build one. But if you look at other velomobiles on the Internet you wil see that he faired pretty well with his build.

  2. Hello Everyone!
    I have been reading the comments about my velomobile that HAD was kind enough to post about. I agree with some of the comments about the weight of my velo. I thought it was a bit heavy too until I did a little more research online about velo’s that are for sale. I found some to be less then my weight which was expected and a lot more of them much heavier. I saw one that was 110 lbs! The lightest one made of carbon fiber I found was only 44 lbs. But then you get into the cost of that one being around $10,000. All most more than four times the cost for me to build this one. One I’d really love to own is closer to $18,000! Ouch to say the least.
    On my to do list yet for this project….aka next years plan. To add electric assist. This would eliminate the slow take-offs from a standing start and aid in climbing hills. I’ll ride it the rest of this year, get my legs in shape and see how it goes from there. With any project there is always room for improvement. This project is no exception. But with this being the first velo I’ve every built I know the next one will be that much better. Thanks for your comments. Dave Langkamp…The Tinker’s Workshop

  3. Home built. Home learning. And it doesn’t matter what it ‘lacks’ from other peoples point of view, it’s what the builder wanted. And it’s pretty dang slick I think.

    IT HAS STRIPES. And everyone knows that red is the fastest colour.

  4. I think your all missing the most important point here, he took a recumbent trike, the stupidest looking form of transportation man has ever invented and made it look cool, AND IT HAS STRIPES!

  5. he did not build it himself. he bought a trike and put a shell around it. sorry but i have to agree with others wondering as to why this is here other than a shiny coat of paint over the shell. just because the ribs were printed doesn’t mean this was a feat. all that plastic adds weight and I have ridden and built these that adds up quickly. Do it right and shape them in foam and wrap them in carbon fiber and add increased substructure where needed.

    sorry for the rant but just because this is shiny and used a 3d printer doesn’t mean it belongs.

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