Unmanned Aerial Vehicle (UAV)

16 Foot Wingspan Flying Wing


Christopher Good
Lead Avionics Engineer for Shadow 200 UAV,
AAI Corporation, Unmanned Aerial Vehicles Division
Graduate Student, Master of Science, Mechanical Engineering
Department of Mechanical Engineering
University of Nevada, Las Vegas

Home email: chrisgood@comcast.net
Work email: good@aaicorp.com  


Description and Overview

This Master's Project is an on-board autopilot program running on microcontroller that will control a dynamic system; an aircraft in flight.  The aircraft is a 16 foot wingspan flying wing modeled on the Northrop N-9M flying wing.  Three aircraft have been built, an 11 foot testbed, a proof of concept half scale 8 foot aircraft, and the full size 16 foot wingspan aircraft with the computer on-board.  The onboard computer has an autopilot program. Eventually, a RF modem will be used to downlink real-time telemetry to a ground computer and uplink flight commands from a ground computer.

The N-9M flying wing was itself a scaled down version of the XB-35 long range bomber designed by Jack Northrop and his engineers in the 1940's.  The XB-35 eventually became the YB-49 medium range bomber.  It lost out in competition to the B-36 Peacemaker after some unusual circumstances surrounding its showing to the government at Andrews AFB. To see more of the only remaining real N-9M, go to the Planes Of Fame Museum.  If you want to learn more about flying wings, go to the Nurflugel site.  It is an excellent site that has details on just about every true flying wing that has ever flown. Airfoils, airfoil analysis software, and links can be had at my Software Page - airfoil section. The pictures below are all thumbnails - click on the picture to see a full size photo.


N-1M


N-9M


XB-35


YB-49


B-2 Spirit

YB-49_card_front_tn.jpg (9722 bytes) YB-49_card_back_tn.jpg (12370 bytes) Brigadier General Robert Cardenas was the chief test pilot for the Northrop YB-49 Flying Wing.  I worked with his son on the Army's Extended Range Multi Purpose unmanned aerial vehicle, a derivative of the Predator.  His son gave me this card, from his father, when he learned I was working on a flying wing UAV.
uav_wing_1_before_flight_attempt_tn.jpg (11955 bytes) Update September 2006:  Flight was attempted during August and September 2006, but my club's paved runway is only 150 feet long.  The plane would begin to rotate but could not get off the ground before running into the grass off the other end.  Several attempts were made with extra pushes and run-ups before the pavement.  I then swapped in the OS 91 VR-DF engines and fans from my SR-71, and got the same results. I need a longer runway. Here is a shot from before the attempt at flight.

wing_7oct07_tn.jpg (11566 bytes)    wing_preflight_7oct07_tn.jpg (16050 bytes)   takeoff_run_start_7oct07_tn.jpg (7469 bytes)   flyby_7oct07_tn.jpg (4170 bytes)

Update October 2007:  IT FLIES!  My club's runway was extended to 325 feet during the last week of September 2007, and I took the wing to the field on October 7, 2007 to try again.   After using a lot of the runway, I kept pulling back and found that I needed full back on the elevator stick to gain altitude.  I made three patterns around the field and came in for a very nice landing. I need to do three modifications to make it fly better: increase the size of the elevons, remove nose weight to move the CG back, and move the main landing gear back to accomodate the new CG.

Update November 2007:  I originally had 4 pounds of lead in the nose, and have now removed 2 pounds of lead.  This moved the CG back about 1.75".  I also moved the main landing gear back 2.5" and increased the elevon throws at the radio from 100% to 150%.  November 4, 2007 was the fist chance I had to fly it again in calm winds.  It flies much better now!  It only used about half the runway.   It still required a little up elevator for level flight, but I was able to dial that in with just the radio trim. It then flew hands off straight and level.  It flew for many laps around the field, until one engine died and I brought it in for an even better landing than the first flight.  I will remove another 1/2 pound of nose weight, and possibly add adjustable needle valves to each engine.

             

Update April 2009: I proved the wing would fly powered by ducted fan engines, but they are so loud I could only fly it a few times a year. I removed the OS 91 VR-DF engines and fans and installed a Super Tigre 3000 30cc engine.  The new version takes off in about 50 feet, and flies easily at 1/3 to 1/2 throttle.  Look at the last video below. I flew the wing twice on 5 Apr 09.