For the rotorheads....

I got something like that for christmas. It was quite fun to hover around. once you crash it into a wall/ceiling fan/or floor a few times it stops flying quite as straight which makes it a little more challenging. of course eventually the thing self destructs like real helicopters :) (jk Bob!)
 
tonycondon said:
I got something like that for christmas. It was quite fun to hover around. once you crash it into a wall/ceiling fan/or floor a few times it stops flying quite as straight which makes it a little more challenging. of course eventually the thing self destructs like real helicopters :) (jk Bob!)
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The lesson here? Just like a real aircraft, it doesnt respond well to crashing into things. Doesnt speak well of the person at the controls.
 
I got something like that for christmas as well. But I could never get the darn thing to hover more than an few inches off the ground. Even tried "adjusting" the pitch of the rotors like the instructions say, but it just wanted to fly about 3-5 inches off the ground. :dunno:
 
tonycondon said:
I got something like that for christmas. It was quite fun to hover around. once you crash it into a wall/ceiling fan/or floor a few times it stops flying quite as straight which makes it a little more challenging. of course eventually the thing self destructs like real helicopters :) (jk Bob!)
Click to expand...
I know. The real thing can do a pretty good job of crashing when you let go of the controls, too ;)

The counter-rotating coaxial rotor concept was tried on at least one helicopter -- the Soviet Kamov-25, the idea being that there would be no torque effects. What I don't know is by what mechanism the pilot can induce yaw in the equivalent of a pedal turn, which uses tail rotor pitch change to induce yaw.

Anyway, it looks like fun, but I still like the real thing :D
 
That's pretty cool, thanks for sharing!

I have a helicopter kite I got as a gift a few years ago. It never flew well for me - operator error I'm sure - but it is a nice decoration to have hanging above my desk. My experience with flying anything but a full scale aircraft has not been exactly good for the equipment.
 
Crap. It's sold out. I would have bought it. I am easily entertained.
 
jangell said:
Crap. It's sold out. I would have bought it. I am easily entertained.
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Yeah, it sold out in a day. I'm going to try to get on their list to be notified when it's back in stock.
 
http://www.aerospaceweb.org/question/helicopters/q0034.shtml

"Yaw control is achieved by increasing the blade pitch on one rotor while decreasing the pitch on the other. The result is a differential in torque, resulting in a yawing motion. The most notable advantage of the twin coaxial arrangement is that it is very compact. Although the twin rotor configuration tends to be rather tall, the lack of a long tail boom results in a very short fuselage that takes up much less space. For this reason, Kamov designs have proven very popular for shipboard use with the Russian Navy. "

http://www.aerospaceweb.org/aircraft/helicopter-m/ka50/

ka50_04.jpg

KA-50 "Hokum"

http://www.globalaircraft.org/planes/ka-25_hormone.pl

ka-25_2.jpg


KA-25 "Hormone"

RotaryWingBob said:
I know. The real thing can do a pretty good job of crashing when you let go of the controls, too ;)

The counter-rotating coaxial rotor concept was tried on at least one helicopter -- the Soviet Kamov-25, the idea being that there would be no torque effects. What I don't know is by what mechanism the pilot can induce yaw in the equivalent of a pedal turn, which uses tail rotor pitch change to induce yaw.

Anyway, it looks like fun, but I still like the real thing :D
Click to expand...
 
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Steve said:
http://www.aerospaceweb.org/question/helicopters/q0034.shtml

"Yaw control is achieved by increasing the blade pitch on one rotor while decreasing the pitch on the other. The result is a differential in torque, resulting in a yawing motion. The most notable advantage of the twin coaxial arrangement is that it is very compact. Although the twin rotor configuration tends to be rather tall, the lack of a long tail boom results in a very short fuselage that takes up much less space. For this reason, Kamov designs have proven very popular for shipboard use with the Russian Navy. "

http://www.aerospaceweb.org/aircraft/helicopter-m/ka50/

ka50_04.jpg

KA-50 "Hokum"

http://www.globalaircraft.org/planes/ka-25_hormone.pl

ka-25_2.jpg


KA-25 "Hormone"
Click to expand...

Interesting post, Steve, thanks. I guess the followup question is how do the controls operate? I suppose the collective would have to act on both rotors. I wonder if yaw is commanded with pedals, and if so, I guess that the pedals must act like collectives, one for each rotor. Or? I have difficulty picturing how this would work since it looks like control inputs are transmitted through two conventional-looking swash plates hooked up in series.
 
Some close up views of rotor system

http://www.kamov.ru/market/encycl/coahe.htm

Pedals are used for yaw control. Instead of feathering the blades of a tail rotor to pivot a helicopter about its yaw axis, the pedals at the feet of the pilot of a coax' alternately feather the blades on both main rotors to yaw the helicopter left or right.

http://www.kamov.ru/market/news/petr11.htm

[rather long explanation of why coaxial is better than tail rotor designs, according to Kamov]
 
Out of curiousity, could you somehow allow the torque of one rotor to overcome the torque of the other in order to turn?
 
Differential pitch of the two rotors. Increase the pitch on one rotor and decrease it on the other. Instant rotor turn.

wbarnhill said:
Out of curiousity, could you somehow allow the torque of one rotor to overcome the torque of the other in order to turn?
Click to expand...
 
Laurie said:
My experience with flying anything but a full scale aircraft has not been exactly good for the equipment.
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This has been my experience too. If anyone saw me try to fly an RC airplane, let alone a helicopter, they would not let me anywhere near the real thing. :eek:

My MS FlightSim skills are sadly lacking too. :rolleyes:
 
Steve said:
Some close up views of rotor system

http://www.kamov.ru/market/encycl/coahe.htm

Pedals are used for yaw control. Instead of feathering the blades of a tail rotor to pivot a helicopter about its yaw axis, the pedals at the feet of the pilot of a coax' alternately feather the blades on both main rotors to yaw the helicopter left or right.

http://www.kamov.ru/market/news/petr11.htm

[rather long explanation of why coaxial is better than tail rotor designs, according to Kamov]
Click to expand...
Good post, thanks Steve!

Sure looks like a lot of stuff to preflight, though :)

That was an interesting article, though I think some of comparisons are exaggerated -- for example the amount of attention the pilot has to give to antitorque in flight -- generally the pedals are only needed when the pilot makes a collective change, and that becomes pretty much automatic over time. On the other hand, it certainly is true that a significant amount of power goes into a tail rotor.
 
Helicopters have always fascinated me. My first ride was in a Bell-47 while in high school that a local rancher used to check his cows and his property. It was like we weren't flying, but the ground dropped away from us. I've also ridden in a Hughes 500C and E, and 300, Bell 206, and an R44.

Coaxial helicopters are very interesting, but that main rotor mast sure looks a might long with all that weight hanging off of it and spinning around it in various directions.

You can always build your own I guess.

http://www.yoshine.com.tw/e-yx24.htm

I have a videotape copy of a documentary entitled "We Were There" released in the mid-50's with interviews of various pioneers of aviation and public figures of the first 50 years after the Wright brothers. One in particular was with Thomas A. Edison pre-WWII in which he comments that airplanes won't amount to much until they can fly like hummingbirds, gesturing up, down, left and right as he speaks.
 
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