A Ring Around Your Wings
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A Ring Around Your Wings
Take eight light blades, surround them with a ring of a chosen weight and shape and we have a very high inertia low total weight system. Such a system would obviously be more costly than a simple two bladed teetering head device, but the cost would be outweighed by the safety. The application would be particularly applicable to light rotorcraft or even a 22. Thoughts??
Given the number of little plastic toys on the market that share this very design feature, I'm guessing that a number of aeronautical engineers have examined and discarded this design on multiple occasions already.
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>Given the number of little plastic toys on the market that share this very design feature, I'm guessing that a number of aeronautical engineers have examined and discarded this design on multiple occasions already.
Or maybe a liability issue with little fingers in rotating blades......
Or maybe a liability issue with little fingers in rotating blades......
Wouldn't restricting lead and lag cause tremendous vibrations? How would the blades feather? Or cone? What if the track and balance isn't perfect? What about the aerodynamic effects that this ring would have? At the least, it would cause a lot of drag.
What is the advantage over just stuffing some weights into the blade tips (see Robinson)?
What is the advantage over just stuffing some weights into the blade tips (see Robinson)?
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a ring around your wings
Tests have shown that there are in fact less vibrations within a contained blade. The blades feather just as per normal as they are allowed to pivot within the ring. Track and balance needs to be perfect as does any rotor system. Aerodynamics show positive results when evaluated by FDA. Increased drag is compensated for by increased eficiency around blade tips Due to improved tip loss factor. Stuff more weight on the tips of Robinson blades, and they will depart from the hub unless the hub if beefed up. Heavier hub, more power required to lift. Bug.
How will the blades flap to equality?
The rings will be a royal pain to store in a hangar, unable to move the blades around to mesh the machines in tighter.
The ring will possess some unwanted gyroscopic properties, perhaps?
Balancing will be a trick, too, with 360 degrees of different places to shove a weight. But perhaps more accurate.
Will the ring be fitted when the blades are flapped up? Or level? Because when the spinning stops, the blades want to sag down, but the ring will stop that, causing some compression stresses - blades are usually only stressed for expansion stresses.
The rings will be a royal pain to store in a hangar, unable to move the blades around to mesh the machines in tighter.
The ring will possess some unwanted gyroscopic properties, perhaps?
Balancing will be a trick, too, with 360 degrees of different places to shove a weight. But perhaps more accurate.
Will the ring be fitted when the blades are flapped up? Or level? Because when the spinning stops, the blades want to sag down, but the ring will stop that, causing some compression stresses - blades are usually only stressed for expansion stresses.
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Bug, have you discussed a project with Robinson (for example)? You might be able to persuade them to lend you a development machine, and give you access to their engineering department. If you convince the engineers (and you seem serious enough to me) then the engineers will convince the MD to take trials further.
Perhaps a better route would be to talk to some of the engineering teams developing rotorwing UAVs and suggest that you can provide some expertise for the rotor system development. Working on your own is always going to leave you idea as an outsiders.
Just my £0.02.
Perhaps a better route would be to talk to some of the engineering teams developing rotorwing UAVs and suggest that you can provide some expertise for the rotor system development. Working on your own is always going to leave you idea as an outsiders.
Just my £0.02.
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a ring around your wings
Having consumed a number of glasses of wine, i am not in a condition to answer questions regarding technical aspects of this innovative rotor system. However when of clear mind i will respond. I do have the answers to all of the questions put foreward so far. The picture above was in fact last years model. A new machine designed to accomodate a full size rotor system was displayed at Helidays this year albeit with a mock up full size rotor system. Bug.
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A sobering thought; 
- Place a shaft inside your hollow mast.
- Drive this shaft in the opposite direction from that of the mast.
- Locate a planetary gear-set at the top of the mast.
- The shaft drives the sun gear.
- The hollow mast drives the planetary gear holder.
- A circular mass is attached to the outside of the ring gear by a universal joint.
- A strong swashplate is attached to the bottom of the circular mass.
- Two rod extends down from this swashplate to the root of each of the two blade.
- The blades are given hub-springs.
- The circular mass provides the increased inertia.
- Plus;
- The weight of the inertia can be lighter because of its very high rotational speed.
- Plus, Plus;
- The craft now has greater cyclic control due to the moments created by the hub-spring on the rotor and the teetering of the rotating mass.
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a ring around your wings
Dave. Whilst still not clear of mind, are you suggesting a contra rotating double ringy thingy. How much inertia can a chap handle? Bug
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Bug,
The circular mass will rotate in the same direction as that of the rotor.
The following line should have been included when typing up the previous list;
In other words there are 4/rev sinusoidal moments, at approximatly 90-degrees, applied to the mast when the pilot has his cyclic stick off center. This moment is in addition to the force at the top of the mass due to the pull of the tipped rotor disk.
If the above is confusing, try here. This is the same concept but it is more confusing because the 'rotating mass' is the electric motor that powers the rotor.
Dave
The circular mass will rotate in the same direction as that of the rotor.
The following line should have been included when typing up the previous list;
- Two additional rods, which are located with a 90-degree azimuthal offset from the previously mentioned two, extend down from this 'strong swashplate' to the mast.
- The hub springs are located between the teetering rotorhead and the mast. When the rotorhead teeters it imparts a 2/rev sinusoidal moment to the mast 90-degrees after the azimuth of maximum teetering rate. This contributes to the 'tipping' of the craft.
- When the rotorhead teeters it also imparts a 2/rev sinusoidal moment to the the rotating circular mass, and this imparts a 2/rev sinusoidal moment to the mast 90-degrees after the azimuth of maximum teetering rate. This, also contributes to the 'tipping' of the craft.
In other words there are 4/rev sinusoidal moments, at approximatly 90-degrees, applied to the mast when the pilot has his cyclic stick off center. This moment is in addition to the force at the top of the mass due to the pull of the tipped rotor disk.
If the above is confusing, try here. This is the same concept but it is more confusing because the 'rotating mass' is the electric motor that powers the rotor.
Dave
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At the risk of getting technically boring........
Bug,
If the previous post doesn't have your head spinning, here is an additional idea that you might like to consider. It's yours to patent if it's any good.
Reduce or eliminate the tail-rotor???
The central shaft is rotating in the opposite direction to that of the mast. In addition, this shaft has a rotational velocity that is 4 to 5 times the mast's velocity.
This shaft could possibly drive a rigid propeller (small rotor) that might counteract some or all of the torque generated by the main rotor.
Dave
If the previous post doesn't have your head spinning, here is an additional idea that you might like to consider. It's yours to patent if it's any good.
Reduce or eliminate the tail-rotor???
The central shaft is rotating in the opposite direction to that of the mast. In addition, this shaft has a rotational velocity that is 4 to 5 times the mast's velocity.
This shaft could possibly drive a rigid propeller (small rotor) that might counteract some or all of the torque generated by the main rotor.
Dave