"Whoops! I've been thinking about pusher props above wings.... "

"With all motors in a single plane, you want to find the average thrust line. But this is not what you're asking. Any thrust line above the wing will tend to push the nose down. Any thrust line below the wing will tend to push the nose up.…"

"By the way, 2 part epoxy will harden even in large pieces (you can fill spaces with it). White glue only hardens where it is exposed to air (It makes a bad filler, as the inside doesn't harden.)"

"Craig, Make sure that the center of gravity is about 25% back from the leading edge of the main wing. Make it balance here -- don't rely on this or that size battery to balance it. Without this right, the plane just will not fly. Make sure that…"

"I agree with the comment that this is not a military UAV site. I have reservations about the managerial efficiency of anything overseen by DARPA. I have serious doubts that Boeing or Lockheed or the big aero boys have practical experience building…"

"NO need to be discouraged! Until you've toasted about 3 dozen planes, you have not seen many of the things that can go wrong! The difficult thing is having the guts to learn to fly.   1.  get the basics very close to right before you…"

"What is your flying skill level? (If none, you need to learn how to fly first.) What types of planes are they? (Different types require different skill levels.) Do you have a computer RC flight simulator? (Fly the same type of plane on a simulator…"

"Ducted fans are really inefficient. Go prop, and use the biggest prop possible (lowest rpms. The hobbyking global hawk is a foamy. It is a disposable experiment, but not as reliable as a builtup plane."

"Ailerons make it easier to level a plane for landing. You will get more landing crashes without ailerons. This is a well known curse of beginning fliers (who may want all their controls on one stick).   You cannot create an autopilot to fly…"

"A comment on wing mounted motors --   I tried the nitroplanes UAV (55") and a slightly beefed up 3xx42mm motor. The thrust line was too strongly down, and the plane wanted to fly outside loops.     So even if the pod is big…"

"Oh! I answered the wrong question!  Sorry.   Delta wings (like the Bobcat) and normal wings have very different balances. But if you attached the new wing and made the Bobcat balance at the same CG (right in front of the metal wing tube…"

"Do you mean how would the Bobcat thermal (fly up without power, in a rising column of air), compared to a glider?   The Bobcat will not thermal. The wing loading is too heavy, and the glide ratio (number of feet it goes forward, divided by the…"

"The 51" Bobcat hanging on my wall has a fairly thin airfoil, and semi-symmetrical. It should give some lift, but will have to fly pretty fast to stay in the air. It will not slow down much to land, or cruise. Empty weight is maybe 5.5 lb, which…"

"Speed and efficiency of flight are important. Look at the type of the airfoil (effects flight speed, and glide efficiency), and whether or not you can put a power system on it that is acceptable. For efficient flight, you will need lifting wings…"

"The modern weight would be more like 5lb, for a 3m competition sailplane. I think that a UAV should be going a bit heavier, and a bit more rugged."