Micro Mini Air Vehicles: MAVs – Fantastic Fairy Flyers Sprint Courses 1. Sailor of the Southern Skies   1 hour seminar - public invitational Intro To Lift, Drag, Power, Flight Dynamics and Control 2. The Raven’s Way   3. Design of Ultra Light Structure   4. Response of Small Flight Systems in Turbulence Group members Meetings

 

Micro Mini Air Vehicles: MAVs – Fantastic Fairy Flyers

 

The whole business of small unmanned radio control aircraft has literally (a word I try to use correctly) taken off.  Flight systems of less than 10 cm wingspan with weights in the 10-2.5 gram range and endurances of ten minutes can be bought, Ready to Fly (RTF), for less than $150 and flown right out of the box.  Because of the square–cube relationship, and graphite airframes they are incredibly strong, and can hammer into objects, inflicting more damage than they suffer themselves.  I hold patents (1980) on one of the first professional small military Unmanned Air Vehicles, the Pointer FQM 151-A. Squadrons of Pointers are in service now with the US forces. They seem to be indestructible! We couldn’t break that aircraft.  When one flew into trees or bushes, pieces of foliage came busting out but the Pointer relentlessly bored on.  It was equipped with color TV cameras and recorders, GPS, no ailerons, a deep stall recovery system and an inclined gyro stabilizer (the main basis for my patent).  Armed services loved it. It was the smallest of its time, but, at 2 m and 4 kg, gigantic by current standards.

 

The funny thing about these micros is that any wacky configuration seems to fly just fine. Configurations looking like hamburgers, plastic dishes, Snoopy Type doghouses, watermelons, birds, bees, butterflies have all been made and flown with elegance.  Even ornithopters, notoriously unstable little buggers, can be handled without too much embarrassment.  A’course, thanks to micro electronic magic they are all wonderfully overpowered and have dominating control authority – the two features, as  I know from personal  experience, that are  adored by any test pilot.  Amazingly, hobbyists continually find new ways of developing light weight control servos, current actuators are in the 0.025 gm range, and the rest follows.

 

It would be enjoyable to have a sorta MAV “gentlemen’s” club here in Santa Fe.  Name it in Spanish, sumpin like the diminutive of raven, or mosquito!  A small indoor space for flight is desirable and some rudimentary equipment – a few benches, some micro electronics tools and gages, a thrust dynamometer and (praises be) a small wind tunnel.  I know roughly how to do these things, and in the Dark Ages supervised a professional group doing this for big $.  The most useful thing about such a group would be the information exchange. Someone always has the answer to your personal problem.  One could invite the local youth and students, say Saturdays, to let them have at it, but I despair of the intelligence and perseverance of young people these days.  For my part, I would enjoy giving a few informal one hour lectures on Aerodynamics, Structures, Flight Dynamics and Control and Atmospheric Turbulence.  I do know something about the above, and was once well paid to teach them.  The R/C, electronic features and electric power are not my bag, but I’m sure someone could do this.

 

General idea would be to buy a few RTF kits first (fixed wing and orniflopper), and have at the skies.  Let everyone have a go.  This would then degenerate into people’s assuming they could do better (Santa Fe folks seem to take that for granted) and doing their own designs.  I personally want to build an R/C flapping flight replica of Leonardo’s 1504 Fiesole Flyer.  Yeah, I know, I know, he almost certainly never did, but one can dream! 

 

Sprint Courses

 

1. Sailor of the Southern Skies

 

1 hour seminar - public invitational

This is a theoretical scientific seminar of the methods by which the southern albatross

(Diomedea  Exulans) extracts energy from the oceanic boundary layer, as first noted by Lord Rayleigh and, poetically, by Coleridge in “The Ancient Mariner”.  This great bird flies many thousands of kilometers on stationary, silent wings.  The primeval flight energy extraction procedure makes its existence possible. The analysis involves optimization of nonlinear, extreme angle flight mechanics in a spatially varying wind field, and some simple variational techniques.  The results are supported by a short VCR clip, showing the process.

 

Many of the discussions of this topic on the web, and in ornithological literature, including a recent authoritative volume by Oxford Univ. Press,  are incorrect.

 

The lecture has been presented at American Instit. of Aero- and Astronautics, NASA, Caltech, Stanford, USC, UNM and other places.

 

Intro To Lift, Drag, Power, Flight Dynamics and Control

 

 

 

2. The Raven’s Way

 

This is a theoretical scientific seminar on the methods by which birds

extract energy from atmospheric turbulence.  The flight techniques are enthusiastically exploited by the great American Raven (Corvus Corax) and  can be observed ubiquitously in the  Santa Fe skies

 

This work formed the basis of a recent Ph.D. thesis by Chinmay Patel at Stanford University for which the author was an advisor.  The analysis methods involve complex flight mechanics with feedback from atmospheric turbulence.  It involves optimization of nonlinear, extreme angle flight mechanics.

 

Patel flew a 2 m model R/C glider, with computer controlled feedback response, and was able to maintain altitude, unpowered, in mild turbulence in flight test.  A book on his thesis is being published.

 

The author and Dr. Patel have presented seminars on this at AIAA, Stanford and other places.

 

 

3. Design of Ultra Light Structure

 

This is an 18 hour short course designed for engineers to acquire skills in  stochastic load definition, modern load path analysis, and advanced composite materials.  It is intended for aero engineers with the usual academic engineering background, who have worked in traditional aerospace design.   Interest has been intensified by the recent awarding of a number of contracts from DARPA for the new Vulture Program.

 

The course has been given at AeroVironment, USC, Lockheed Skunk Works (California), Lockheed Martin, Fort Worth and is scheduled for other high technology corporations in the future.

 

 

4. Response of Small Flight Systems in Turbulence

 

This study is being conducted privately for a Washington agency, and is aimed at determining why small vehicles are so prone to atmospheric upsets.  The topic is of importance because of the utility of small unmanned air vehicles for various military and civilian missions.

 

In the natural world the smaller flyers start walking at various wind speeds:  butterflies at 1 m/s; gnats and midges at 2 m/s; bees, beetles, wasps and swallows at 7 m/s.  Indeed, even very large light aircraft, like the human-powered Gossamer Condor could not be flown at winds speeds exceeding 4 m/s.

 

The study analyzes the lateral response of vehicles of low relative mass, and calculates their behavior in low altitude wind fields, at less than 5 m height.  Comparison with various legendary low speed rough air flyers, including the jackdaw and raven, the Fieseler Fi. 165 Storch, (the well-known Luftwaffe VSTOL flyer) and the AeroVironment Pointer, a hand launched unmanned air vehicle, used currently by the US forces.

 

The analysis involves the interaction of the wind field and the vehicle flight dynamics, as well as the probabilistic nature of atmospheric turbulence.  Insights into the airframe design features, and active damping controls, that will minimize the upset probability are derived. This work is in progress, and has not been presented publicly.

 

The Presenter

 

Peter Lissaman has a Ph.D. in aeronautics from Caltech, and advanced degrees in Math from Cambridge Univ., in ME from Natal University and an Honorary Ph.D. in engineering design from Natal University. He was awarded the Longstreth Gold Medal by the US Franklin Society (previous recipients were Orville Wright and Thomas Edison) and the Kremer medal from the Royal Aeronautical Society.  He has taught many students, from Navy test pilots to Grad students at Caltech, USC, and Stanford.  Some of his students went far – two to the moon!  He is a designer of operating aircraft, sailboats, wind turbines and automobiles, and has published more than 160 papers on subjects ranging from wing theory and bird flight to turbulence.

 

 

Group members

 

• Peter Lissaman (Project Director)

               Da Vinci Ventures, Santa Fe  plissaman@earthlink.net

• Robert Holmes
• Stephen Guerin
• Frank Wimberly
• Simon Mehalek
• Shawn Barr
• add your name

 

 

Meetings

 

To Be Determined