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RC Aircraft Flying
Posted: 24 Apr 2006, 09:00
by KODIAK
http://www.freefalcon.com/forum/viewtopic.php?t=13654
Thought the links in this thread might interest a few people here. SOme serious flying here.
Posted: 24 Apr 2006, 22:09
by BlackHawk*K
woot now you hit a subject close to my heart. i havnt flown in YEARS! ( way before marriage and kids lol ) i wasnt realy great at it, and sitll have a few beat up gliders in serious need of repair left out in the garage. ( along with 3 boats, about 10 RC cars, mostly in peices ) i didnt get into planes much, what snaged me were the heli's at one time i owned 3 of em. i had about 1k in one of them, a trainer model. the most expensive thing is the radio. the ones for helies have the tail rudder mixed in with throtle responce. and also the gyro that helps in case of sudden gusts. the bad things about heli's are you have to learn the very hardest thing first. that is hovering. i just got to the point where i could hover and walk behind my heli and do a decent job of it. unfortunatly i sold it due to hard times. havnt been able to afford one since. but ive been searching the web off and on to see whats out there and ran across this intersting page ( makes me wish i had a radio i could do this with!!! )
http://www.angelfire.com/blues/heli_project/
Posted: 25 Apr 2006, 17:43
by Mooseman
here's a question, that may be bordering on the very stupid, but how is some of that stuff possible, and i don't mean just for RC stuff.
E.G. as i understand the way heli's and planes attain lift, they create a pressure difference between the bottom and top of the wing (or rotor blade) which is in essence sucked up. Now on heli's the upside down flying (i can only assume) is possible by a 180 degree switch of the rotor pitch, to generate lift when it's upside down (tho i think that's only possible in 1 real, full-size heli). But how do planes achieve inverted flight. I'd gave thought that even use of elevators et al wouldn't change the wing cross section enough to reverse the lift effect....obviously i'm wrong, because it's possible, but does anyone know how?
Posted: 25 Apr 2006, 17:46
by Hammer
might be a good question for Gator...
Posted: 25 Apr 2006, 18:09
by BlackHawk*K
@ moose.
im not sure exactly all the technical details. but in R/C aircraft, simply the power of the engine can do it. even though the uplift of the wing is reversed, if the nose is pointed up, it will still achieve a climb vs gravity.
its basikly the same principle behind the gyro plane. ( the helicopter looking thing that has to have foward movment to work. )
also its similiar to stunt planes that hover, the power of the engine equals gravity. well you can use the wings at high speed angled upwards to maintain enough lift with a weaker engine. so i think thats how it works ;)
Posted: 25 Apr 2006, 22:23
by BlackHawk*K
Posted: 26 Apr 2006, 05:15
by KODIAK
Smaller wings creating smaller lift (which is essentially what you have in an upside down aircraft) require more thrust to attain the same amount of lift. Thrust is not necessarily equal to speed, but speed in itself is obviously a large factor. The lower your forward speed the more lift will be required from your wings so you will have a greater angle of attack. Hence the reason you see high alpha passes being performed really only at lower speeds.
A pilot flying any aircraft in inverted flight is very likely to be making stick-forward (nose 'down') inputs though.
Posted: 26 Apr 2006, 06:11
by Jedi Master
All that stuff you've read in the starter manuals about pressure on wings is largely extraneous. While the curvature makes the wings more efficient, it doesn't mean you can't fly without it. Several planes have had wings with little or no curvature. The wings themselves are usually not level with the plane ie when looking from the side you can see the leading of the wedge is higher than the trailing edge--this is called incidence. The B-52 has a MASSIVE amount of it, so much that the plane flies itself off the runway once sufficient velocity is reached--no need to pull back on the stick and rotate! Of course, that makes landing a little trickier. ;)
Anyway, the old adage is "you can make a barn door fly with a big enough engine" and it's 100% correct. So a plane in inverted flight generally needs its nose at a higher pitch angle than when right side up...while you can fly at almost 0 degrees that way, upside down you'd likely have to have a good 10-15 degrees nose-up pitch to compensate.