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Getting Air Taxis Off the Ground: An interview with Greg Bruell of Transcend Air Corporation

Inspired by forward-thinking inventions, Vention presents an interview series on product innovation. Our new series will take a behind-the-scenes look at the design and entrepreneurial challenges of groundbreaking ideas in engineering.

Vincent Herman Freelance Writer / Nov 21st, 2018

Transcend Air’s Vy 400 is the modern reimagining of a fifty-year-old concept: the vertical take-off and landing (VTOL) aircraft. Its lightweight carbon-fiber construction will lower operating costs and enhance safety, and it features new advanced avionics and a safety-certified whole-aircraft parachute. The Vy’s tiltwing, fly-by-wire VTOL design makes it three times faster than traditional helicopters, and promises travelers a more affordable and convenient service than conventional airplanes.

Transcend will also launch a new, door-to-door airline service that will transport business travelers between major city centers without the need for airports.

We asked Greg Bruell, co-founder and CEO of Transcend, to talk to us about the exciting technology behind the Vy 400.

How did you get started as an entrepreneur?

My background is in software, and I’ve been involved in startups either as an early member or as a founder for my entire career.

About 6 years ago, I had been doing what I considered fairly run-of-the-mill software and I decided to mix it up. I’d always been interested in planes that took off like helicopters—ever since an early 90s edition of Popular Science featured the Moller M400 on the front cover. Then I found a fellow who had been working on an aircraft. He’d been building models and had a good-looking design, so we decided to make a large, manned version of it, and that’s what we did with Elytron. We took that project as far as we could at the time, but we needed to find a market for an aircraft like that—a small aircraft that took off like a helicopter—and that’s when I landed on the air taxi idea and what became Transcend.

Coming from software, what challenges did you face starting the Transcend project?

There’s always a challenge in building something, regardless of whether it’s software or hardware. Even though I’m building an airplane now, the fact is that there’s tons of software involved.

The biggest leap professionally from the software world into aerospace would have to be the concept of tolerances. We built the gearboxes for our manned aircraft at Elytron and the 2 months we had budgeted for ended up taking 8 months—just because of tolerance issues. The biggest learning curve for me was to always have to be thinking about tolerances as I design or order a part.

The wing on our current 1:5 scale prototype, for instance, is a combination of stock carbon fiber parts wrapped in 3D-printed nylon. Learning about the variances that you get with 3D printing and how to accommodate for that and getting those things to behave in a consistent way has been excellent experience.

Since 2009, Transcend has built and flown 15 prototype VTOL aircraft. Could you tell me about the evolution of Vy’s prototypes?

The first full Vy 400 prototype was a scale model made with standard RC modelling techniques, made from hotwired styrofoam with carbon fiber spars and balsa wood. We had a lot of problems with vibration though, and it was fairly flimsy, with some crashes and significant rebuilds.

With the next version, we made use of quadcopter technology and we went from using helicopter hubs and a collective control to just using motor speed and off-the-shelf, high-end quadcopter motors. The other big evolution in the design was that we actually made a plug and a mold for carbon fiber skins.

The big difference with where we’re at now is having the carbon fiber shells. All of the main structural elements are off-the-shelf carbon fiber tubing, with some stock tubing for landing skids and what we call the “keel” of the aircraft. The spars in the wings are also off-the-shelf carbon fiber, while all of the lifting surfaces and the mountings—all the internal mounting bits for electronics and batteries and such—are 3D-printed.

3D printing has given us a rapid recovery capability, so when you crash a prototype—and you always crash one at the RC scale—you don’t have to spend long rebuilding. The recovery process is “hit print and get a part in the mail.” It also means we can keep spares around instead of building them on demand.

The VTOL concept itself has been around for some time. How has the Vy 400 updated it?

It most closely resembles Canadair’s CL-84, which first flew in the mid- '60s. The lineage for us, though, is that we vector the thrust—that is, change the direction of the thrust during flight—by tilting the whole wing. It’s a tiltwing-derived design.

The other main thread of vectored thrust that’s out there is the tiltrotor, where just the base of the prop rotors on the aircraft are tilted. The Osprey MV-22 and the Leonardo 609 are examples of aircraft from that lineage.

Arthur Young, who ended up working for Bell Helicopters, had patents which go back to the '40s covering much of the major design elements. When you do a tiltwing design, you want to have as much rigidity as possible spanning the entire wing. He came out with a patent for a design where you have this cutout and you’re able to maintain a single leading edge spar for the whole wing, and that design is still the best way to do it.

However, we get to take advantage of all of the material updates since then—carbon fiber especially—so things like driveshafts are much lighter. All of the power-to-weight ratios for the engines have improved over the years, so in some cases we’ve got twice the horsepower for the same weight.

The BRS Airframe Parachute allows us to have a single engine, and that radically changes the design requirements. We have this ability to recover in an emergency—whether it’s engine failure or anything else—that Cirrus first brought to market in the early 2000s, and has proven effective in keeping people safe. All of those innovations have permeated the design of the Vy 400.

Why not use batteries instead of a jet engine?

You can’t do a city-to-city flight economically with batteries—the energy density just isn’t there yet. Jet fuel is one of the most efficient ways of carrying around energy you can get without going nuclear.

I like to talk about our design as being fairly conservative, which is to say that we’ve tried to pick up as many certified, off-the-shelf parts we can, so only the VTOL piece of it is unique. I think we’ll get to market as quickly as possible and reduce our risk by picking up pieces and parts that are already certified and ready to go.

If you look at the very light jet market from about 10–15 years ago, the leader of which was Eclipse, they tried to introduce a lot of new technologies all at once and that made their certification process and their schedule balloon out. Similarly, our eVTOL (Electronic Vertical Take-Off and Landing) brethren have a much higher hill to climb, and they will have a lot more to prove to the FAA than we will.

What’s next for Transcend?

Right now, we’re proving the basics of the design: we fly models and we go into the wind tunnel. That’s all meant to demonstrate what’s called a T-Pattern flight at the fifth scale: take off like a helicopter and convert to a plane, fly like a plane, then convert back to a helicopter and land. The next step is moving to the half scale, and then we’ll go for a full-scale concept.

Coming from the software world, it’s interesting how systematically we have to go through this process of scaling up in order to make sure that the aerodynamics work and that as you make a larger and larger aircraft, that they continue to work. Here, you have to crawl before you can walk, and you have to walk before you can run.

Want to learn more about Transcend?

Watch their official teaser

Or visit to learn more about their project.

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