AboutPaul Soderman Expertise Aeronautics, Fluid Mechanics, Aeroacoustics, Noise Control, Muffler Design, Wind Tunnel Research.... I know nothing about India - do not ask about schools, jobs, application requirements, career choices, etc. for India. Please, no text message verbiage; I prefer full words in full sentences. Thanks.
Experience 38 years as research engineer at NASA
Publications AIAA, NASA
Education/Credentials B.S. and M.S. Aeronautical Engineering - U. of Washington
Graduate work Standford U.
Awards and Honors AIAA Associate Fellow (American Institute of Aeronautics and Astronautics)
Thanks for being willing to answer questions. To help with inspiration for the fictional heavy cargo aircraft design that I am doing as a thought experiment, I have been looking at other people's fictional ideas. This has led to some questions that I can't answer, so I would like to ask you for help.
For example, the upper picture shows a fictional idea for a mid-21st century high end luxury business jet. Since I am not trained in aeronautics, I wondered if you could give the upper picture a once-over for any opinions on what characteristics you think it would have if it were real. Would it be stable and safe to use? I look at the dorsal and ventral C/L antennas, and worry that in real life, they would be sheared off. The plane looks a bit like a Rutan Quickie, but much larger. Am I right that it would be stable in roll axis, but that in real life it would be slow, and turn poorly? I am puzzled by interesting details like the weird configuration of jet engine inlets and outlets, and I don't understand the third engine aperture, which is on the side -- why, and for what service ceiling? The things that look like roll stabilizers on the rear airfoils for some reason make me think of the A-10 Warthog, but why have two stabilizers on each wing? Perhaps there are not really two, but instead maybe the wingtips have been split, and set off at 45° from each other, appearing like a second, smaller pair of stabilizers? I think I've heard of a design like that, but I can't remember. And what on earth are those enclosures near each wingtip, pointing aft? Would wings like those perhaps be more at home on a big cargo plane than on a big business jet?
Much simpler questions about the lower picture. What are the reasons for the spiky projections marked by circles? Are those that point upward also roll stabilizers, like those in the upper picture? And the two horizontal things that the tilt-rotors are connected through, which have driveshafts inside, are they properly called "wings," or just "airfoils?" Also, would an aircraft that had more than two pairs of tilt-rotors technically count as a tandem-wing aircraft? Finally, it seems like tandem-wing aircraft always need to have wings of different spans, fore versus aft, and the wings with longer span need to be the ones behind. Is this true? I ask because I have seen other three-view drawings of the proposed V-44, and they all seem to show the aft span greater than the forward span.
Thanks very much, I am extremely grateful for your help.
Answer Julian
I wouldn't put much credence in an artist concept aircraft. We can't say much about performance just from the picture, but it seems to me that there are too many vertical stabilizers in the design. And I certainly wouldn't want to stick one in the middle of the wing. I can't make out the engine geometry - if the intakes go over and under the wing one has to wonder why. And the canard seems overly big. I wouldn't want to enter that door with the engines running.
The VTOL machine seems to have winglets and antenna that are circled. The aft wing span is large so that the wake from the forward propellers miss the aft propellers more or less. There is no other rule for tandem wing size that I know of. The propellers or rotors are mounted to wing sections that rotate. The spikey projections aft of the wing are unknown. It looks like a clumsy hybrid that is part helicopter part aircraft. But I guess almost anything can be made to fly with enough power and control.
Paul
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