the prop fits over a nut so i use the 3mm locknut in there. on the top and the bottom, i use a regular 3mm nut and tighten it against the prop. kinda like putting a tripple lock nut assembly on a four stroke. as the tightening nuts the nylock oneswon't do much good. i used the nylock on the propeller becuase it has more side area and the prop fits over better. it is tough to fly a draganfly oriented craft without gyros. becuase of the design, it is far more sensitive to radio glitches, wind etc and the gyros help correct it. the real draganflyer has gyros too. as far as the rudder goes, you can use tilt rotor, but it is probably going to cost more to have the gimbals manufactured than to buy the veetails. (the vtail method electronically mixes the motors so that one rotating pair speeds up and the other pair that counterrotates the other slows down causing torque to turn the model) it is much lighter and has no mechanical possibility of failing in flight. however, the gimbals would prevent it from becoming unstable when too much rudder is applied. that shouldn't be much of a problem however as the rudder in this type of thing is more of a correction than anything. either way is good. i just prefer the electronic way because it can't fail in flight or be affected by vibration and it weighs only about 1.5 oz for all three mixers. the real draganflyer uses highly geared 280s i think. you might want to go to www.spectrolutions.com and email mike. i think he was the electrical engineer. the props spin no more than 1000 rpm, so they are very undercambered and flimsy and the pitch on the props is also inconsistant from blade to blade so higher rpms won't work very well at all. if you plan to gear it down to those rpms, do note you aren't going to get much thrust. the real draganflyer weighs about 1 lb (half as much as mine but mine is bigger) so the thrust-weight ratio is probably anywherre between 1.5:1 and 2:1. i understand it doesn't have too much power. however, because of the steeply undercambered blades pitch and roll response is more sluggish but more effective (because of the lighter rotor disk loading) than my design. as far as technical specs you could again ask mike. if he does not know he probably knows someone who does. his website is very out of date but you can also get some draganflyer parts there. it has been so long that they may have stopped carrying it. also, www.draganfly.com might have technical specs or contact info for you. oh one more thing about the gimbals. in a model airplane news magazine, i noticed an article about a guy who did it wiht 2 props instead of four and used gimbals to do it. you can look over his stuff at www.gressaero.com and look around. you can contact the guy, he is very nice. you might be able to ask him about the gimbals. gimbals or electronic method is really a matter of preferance and what is most available to you.
cheers