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Old Mar 09, 2002, 03:21 PM
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Sikorsky CYPHER

Check this out for ref.

For as cool as this thing is, I'm surprised that it seems so hard to find info on it, and that it doesn't seem to be discussed much when the ideas for VTOL craft are batted around.

It seems that when people talk about non-helicopterish VTOL RC models, people look to the Hiller flying platform when talking about single axis craft, or multi axis designs like the Draganfly, the Vectron Blackhawk.

Has anyone ever seen or built a RC model that follows the CYPHER design?

Has anyone seen any sources that give more detail on how the guts of the CYPHER work?

Obviously I'm not interested in building in the stuff like thermal imaging, automatic target detection, or battlefield managment right off the bat!

Another question on the CYPHER is on THIS page toward the bottom 1/3:

What is "coaxial advancing blade concept (ABC) rotor system"? I can figure out what a few of the words mean ( ) but I'm curous about what is implied by the way they are strung together. Specfically the implication of the "advancing blade" bit.

This place is so full of bright people that seem so willing to help out goofballs like me that I'm sure someone will help me!

Thanks in advance.
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Old Mar 10, 2002, 01:02 AM
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Hi!

Look here for info about the Advancing Blade Concept.

http://www.synchrolite.com/0891.html

Nick
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Old Mar 10, 2002, 01:58 AM
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This is interesting the links suggest that these contra rotating coaxiall rotors would work better if more rigid. The nature of materials suggest that the smaller you make this design the better it would work Hmmmm
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Old Mar 10, 2002, 03:21 AM
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Quote:
Originally posted by nullman
Hi!

Look here for info about the Advancing Blade Concept.

http://www.synchrolite.com/0891.html

Nick
Cool! Thank you.

I'm not sure I'd wanna fly in THIS though!
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Old Mar 10, 2002, 03:28 AM
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I saw an RC project just like it back in the 70's.

It was the same platform of your project with an IC motor. The wash was vectored by fins under the prop. I never saw it fly but it would be much easier to now with comp radios and gyros.

With todays batteries and BL motors it seems very workable.
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Old Mar 10, 2002, 03:37 AM
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Quote:
Originally posted by Fred Bronk
I saw an RC project just like it back in the 70's.

It was the same platform of your project with an IC motor. The wash was vectored by fins under the prop. I never saw it fly but it would be much easier to now with comp radios and gyros.

With todays batteries and BL motors it seems very workable.
Here's a naive question...

Why would a design like that need gyros at all? It seems that the counter rotating blades would provide the anti-roll stabality. What would the gyros control as there would be no cyclic ability, and in a FP design, no collective either?
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Old Mar 10, 2002, 01:29 PM
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Quote:
Originally posted by Monkeyfarm


Here's a naive question...

Why would a design like that need gyros at all? It seems that the counter rotating blades would provide the anti-roll stabality. What would the gyros control as there would be no cyclic ability, and in a FP design, no collective either?
Ah well... in fact contra rotating blades actually dont have a gyro effect because the gyro moments cancel out. Also there is no reason other than complexity why you could not use cyclic control. The links posted above lead on to descriptions of cyclic versions. however as Fred Bonk says fins an also be used to vector the thrust. The three dimensional CG must be critical though or the effect would be to amplify any movement whchever way the fins tilted. If so the cg despite the appearace in the piics must be below the vectoring arrangmment. One can imagine a slight tilt wiith a higher cg... the vectorfins move to compensate and instead increase the tilt if they move the otherway they accelerate the motion!
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Old Mar 10, 2002, 02:17 PM
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Thanks Aubrey!

Using what is availible now it is very workable at a reasonable price.

If you want to do it the same way they are, you will be on virgin ground and it will get expensive!
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Old Mar 10, 2002, 10:31 PM
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Quote:
Originally posted by Aubrey


Ah well... in fact contra rotating blades actually dont have a gyro effect because the gyro moments cancel out.
What's the difference between contra and counter rotating when referring to blades?

Or is this just one of those deals where the biggest thing seperating the old English Empire is a common language?

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Old Mar 11, 2002, 08:02 AM
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Probably! although contra seems to be popular in America too some chaps called Reagan and North had a problem with a "contra revolutionary force" as I recall
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Old Mar 11, 2002, 08:44 PM
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"Ah well... in fact contra rotating blades actually dont have a gyro effect because the gyro moments cancel out."

I haven't given thus much thought, but it seems that its not that simple. Imagine this: 2 gyros counter-rotating on top of each other, call them cw and cc. From the top view, I you push on the right, cw's top will come towards you, and cc's will want to go away from you. So no matter where the force is applied, the combined gyro will only feel the force along its axis of rotation. So you will still have gyroscopic stability, without unsymetric FFF effect such as the dreaded "pitch up effect" on the Piccolo.
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Old Mar 11, 2002, 08:47 PM
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One more thing its interesting that this type of aircraft would control altitude and yaw by varying collective and torque on each rotor.
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Old Mar 11, 2002, 10:05 PM
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>>I haven't given thus much thought, but it seems that its not that simple. Imagine this: 2 gyros counter-rotating on top of each other, call them cw and cc. From the top view, I you push on the right, cw's top will come towards you, and cc's will want to go away from you. So no matter where the force is applied, the combined gyro will only feel the force along its axis of rotation. So you will still have gyroscopic stability,<<

Your right its not that simple it takes about a two pages of math to prove. much depends on riigidity and how well coupled the gyros are but the net effect is complete cancelatiion of the gyro effect. The thng is if you look at your statement above you will see you're not thinkng it through. When you push on the right CC wants to go away and CW come toward. BUT cc is therefor pushing CW away whiich makes it want to go right and vice versa and so on adinffinitum. The net result is close coupled contra rotating flywheel pair feels like a brick. the magiical gyro feel disapears.

BTW I have several patents on gyros including micropiezo gyros but feel free to test it for yourself.

Try a toy gyro on an "eifel tower" let it precess atthe near horizontal then stop the precession with a pencil the gyro will drop like a brick. If instead of your pencil the gyro precesssion was stopped by an equal and opposite precession force the result is equally brick like.

You are right there is no gyro pitch up effect iin acotra rotatiion Although there may be other sorces of piitchuup. I myself forgot about the gyro effect re piitch up in another thread as I was concentrating on the aerodynamiics. Obviously if you had a steep cone angle on the rotor that wouldd tend to pitch up gyro or no.
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Old Mar 13, 2002, 06:41 PM
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Right. What I meant is that you would not have the moment phased at 90 degrees but you would still have the damping effect aka stability. What # are your patents, I'd like to have a quick look. I think that this model would be a fun project....maybe in a year or so.
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Old Mar 13, 2002, 10:07 PM
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here is the link to my plasticpiiezo gyro patent.
http://www.delphion.com/details?pn=US04689992__
This patent is lapsed as it was flled wiith respect to a military project that was discontinued. the idea was taken up in several later patents for optical dampling systems for cameras and binoculars and this method or Tehons original "tuning fork" method from1970 form the basis of nearly all miicro gyros today. The Tehon method is better where fast response is more important than sensitivity and the Strachan method where accuracy and linearity are important. I would have kept the patent in force but unfortunately was in hospital recovering from a broken spine and had to sell my company.

feel free to use the original concept if you wish, you can make a sub gram gyro for a few dollars if you are reasonably handy with cyano and fairly simple circuitry in surface mount. Most producton piiezos use crystal or thick film as it is easier to mass produce and so are heavier and less sensitiive than a hand made one.
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