A few months ago, I was talking to one of the inventors and designers of a new prototype. It was a small scaled model with a rotating wing. We got into a rather robust engineering and technical aerodynamic discussion over all of this, and although it wasn’t a debate, we both had different ideas of how we might build a VTOL (vertical takeoff and landing) version of this contraption. No, this design is not new, even in the 1920s there were plans on the drawing board and real-life prototypes which had crashed and burned.
Nevertheless the concept is valid, it does work, and if done correctly it could solve some problems or the challenges of VTOL flight.
First I’d like to say that the transition between vertical flight and horizontal flight is one of the trickiest dilemmas for an aerospace engineer. This is because you are using one set of aerodynamic forces, and changing to a different parameter and set of aerospace physics as you go through that transitional flight phase.
Now then, let me tell you a little bit about the design that I have in mind. I want to attempt to paint a mental picture for you. You know those quad copters that everyone is using now for vertical takeoff and landing, as well as hovering. Perhaps you’ve seen the UAVs (unmanned aerial vehicles), UASs (unmanned aerial systems), and MAVs (micro air vehicles) of this type. Everyone from NASA and DARPA to the USAF and Unmanned Systems Association has been promoting these – and for good reason too, it is a very stable platform.
Of course, it isn’t so good for horizontal flight, unless you can turn all those ducted fans and rotate them 90-degrees for forward flight. Yes, there are some models and some large almost life size prototypes that are able to do this, but realize they aren’t without stability challenges or dangerous risks. Just take a look at the Moller flying car design. If you are unfamiliar with this I suggest you go watch a YouTube video to better acquaint yourself.
Okay so, what if I took the quad motor UAV design and put four rotating wings along a slender fuselage, two on both sides, forward and aft. What if I then had the two in the back facing the opposite direction? As we transition to forward flight, the two in the back would simply turn themselves on a vertical hinge or spindle and slowly face forward.
There would be absolutely no stability problems or challenges while that transition was taking place if it were done in a reasonable time frame preventing inter-rotating wing wash from creating chaotic turbulence (30-seconds to cross the 90-degree point on the mechanic swiveling sequence). As this occurred the aircraft would start moving forward faster until they were facing the exact same direction as the two in the front. Therefore, transitional flight has been achieved without incident or safety issues. Please consider all this and think on it.
Lance Winslow has launched a new provocative series of eBooks on Future Concepts. Lance Winslow is a retired Founder of a Nationwide Franchise Chain, and now runs the Online Think Tank; http://www.worldthinktank.net
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