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Wolfy: Your prop on the 912uls, what make, diameter & # of blades?

You guys mustering have always had my admiration for how many hrs. spent & skills developed from doing so!
 
Smooth rotor judging by the freedom from stick shake in the video clips above.

I can see why those critters would get mean and nasty, having to find something to eat in that scrub land. I guess they mean it when they say Australia is the second driest continent on Earth.
 
Smooth rotor judging by the freedom from stick shake in the video clips above.

I can see why those critters would get mean and nasty, having to find something to eat in that scrub land. I guess they mean it when they say Australia is the second driest continent on Earth.
Certainly a contrast to the footage I have seen of Florida Chuck, I reckon these cattle would die of shock if they were dropped in a Florida paddock. But to be honest there is a lot more feed than it looks on these videos, of the little bit of footage I have got there is not much footage of the good country.

Those rotors were pretty good really, not as good as the light rotors that have been on it but good enough. You may recall I'm setting up a new gyro with a round 4130 mast, I am hoping it will be at least as smooth as that last machine. I did the first hang checks yesterday and it's looking good, with a 7 degree mast and the teeter bolt pretty much aligned with the mast it should be a good thing. Ideally I would like to put some light tip weighted rotors on the new build, but we are down to one manufacturer in Oz now very good blades but not light.

wolfy
 
Chuck if you remember our conversations regarding sweedish yoke's etc, My last post to you came across extremely arrogant.
My apologies mate that was not my intention, but rather was trying to say that I agreed with what you were saying. Sometimes hard to say via typing.

Cheers wolfy
 
Wolfy, if you were arrogant, I must have missed it. Sorry
I’ve been to Oz, but just to the East Coast and must say it didn’t look all that dry but I realize how little rain falls on the interior.
 
I have limited experience with round masts, but I found that the round titanium tubing I used was far more flexible that the square tubing (and also less damped) and I might suggest you make the seat angle attachment from the mast to the front keel a bit higher than with square tubing and also make it possible to adjust up and down a bit to allow for some frequency tuning. I made my 3rd gyro with a welded titanium round tube frame and would have liked to have been able to move that attachment for tuning. I believe optimal tuning will change for gyros as a result of rotor weights, rotorheads, and prerotators making total mass at the mast head different.
 
I have limited experience with round masts, but I found that the round titanium tubing I used was far more flexible that the square tubing (and also less damped) and I might suggest you make the seat angle attachment from the mast to the front keel a bit higher than with square tubing and also make it possible to adjust up and down a bit to allow for some frequency tuning. I made my 3rd gyro with a welded titanium round tube frame and would have liked to have been able to move that attachment for tuning. I believe optimal tuning will change for gyros as a result of rotor weights, rotorheads, and prerotators making total mass at the mast head different.
Hi, can you, please, elaborate a little bit on "far more flexible than the square tubing (and also less damped). Thank you. Georgi.
 
I could watch your videos all day long. I suspect many would love to see musters at work.
Is there a chance I could post them on PRA's Youtube channel?
Two ways to do that I can give you a Dropbox link and you can upload them and I will put them on our page.
Or give me a link to your Youtube channel and I can capture them and then upload them to PRA's channel.
 
Hi, can you, please, elaborate a little bit on "far more flexible than the square tubing (and also less damped). Thank you. Georgi.
Flexible as in how much the tubing bends for a given amount of force. Round tubing is the same in all directions and square tubing is stiffer along the faces or planes as opposed to corner to corner. The Titanium tubing I used was 2 1/4" x .058 wall and was more flexible for the same force as square aluminum tube is along the face. Much of it depends on MOI or simply diameter. Larger diameter with thinner wall is stiffer than smaller diameter with thicker wall for a given mass until buckling becomes a problem. Materials have different damping depending on shape and material condition. Damping can be thought of as the opposite of ringing. Something that rings when tapped is less damped that something that thuds.
I still think Titanium is an excellent material for a gyro, it just has different strengths and weaknesses that need to be taken into consideration in the design.
 
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Flexible as in how much the tubing bends for a given amount of force. Round tubing is the same in all directions and square tubing is stiffer along the faces or planes as opposed to corner to corner. The Titanium tubing I used was 2 1/4" x .058 wall and was more flexible for the same force as square aluminum tube is along the face. Much of it depends on MOI or simply diameter. Larger diameter with thinner wall is stiffer than smaller diameter with thicker wall for a given mass until buckling becomes a problem. Materials have different damping depending on shape and material condition. Damping can be thought of as the opposite of ringing. Something that rings when tapped is less damped that something that thuds.
I still think Titanium is an excellent material for a gyro, it just has different strengths and weaknesses that need to be taken into consideration in the design.
Thank you. I was not clear in my question. Sorry. I know the meaning of those definitions. I wanted to know how those properties manifested themself in flight. Your sensation as a pilot. "Stick feel"
 
I have limited experience with round masts, but I found that the round titanium tubing I used was far more flexible that the square tubing (and also less damped) and I might suggest you make the seat angle attachment from the mast to the front keel a bit higher than with square tubing and also make it possible to adjust up and down a bit to allow for some frequency tuning. I made my 3rd gyro with a welded titanium round tube frame and would have liked to have been able to move that attachment for tuning. I believe optimal tuning will change for gyros as a result of rotor weights, rotorheads, and prerotators making total mass at the mast head different.
Thanks John. My thinking with wanting to go to a round mast is like everyone else, I wanted it to be as flexible as possible. I wanted to keep my seat/forward brace as low as practical to let the mast flex, but never thought of making it adjustable to tune the frequency. That's possibly a very good idea. At one stage I had concerns about maybe my mast being too flexible, so I put it to Chuck. The way I read Chucks response was that there is almost no such thing as too flexible (in this situation) providing your not near the tube design limits. Maybe your method of tuning the frequency is needed after all, but maybe not so much for tuning frequency but rather to keep just within the limits.

wolfy
 
I could watch your videos all day long. I suspect many would love to see musters at work.
Is there a chance I could post them on PRA's Youtube channel?
Two ways to do that I can give you a Dropbox link and you can upload them and I will put them on our page.
Or give me a link to your Youtube channel and I can capture them and then upload them to PRA's channel.
Thanks John, your welcome to use them mate. I have no idea how to give you a link but my channel is just my name Jim Wolfe.
There is more videos coming as I slowly upload them.

wolfy
 
Mast stiffness:

It is not so much a matter of tuning as it is of keeping the inplane resonant frequency of the rotor as high as possible and avoiding resonance at the rotor RPM. This requires both a soft rotorhead mount and high inplane stiffness of the rotor.

Bensen is partly to blame for the 2/rev problem as a result of necking the rotor down to a width of 2.5” at its center. Wide hub rotors such as SkyWheels have fewer problems with 2/rev vibration.
 
Bensen is partly to blame for the 2/rev problem as a result of necking the rotor down to a width of 2.5” at its center. Wide hub rotors such as SkyWheels have fewer problems with 2/rev vibration.

Chuck, been wanting to ask this for ages.

Why the neck down to 2.5"? Why the SkyWheels solution of putting the extra width outboard of the towers? Why not just a wider hub bar?



Miles
 
Chuck, been wanting to ask this for ages.

Why the neck down to 2.5"? Why the SkyWheels solution of putting the extra width outboard of the towers? Why not just a wider hub bar?



Miles

Of course a wider hub would work but would require a wider rotorhead if not going outside like SkyWheels.
 
Of course a wider hub would work but would require a wider rotorhead if not going outside like SkyWheels.

Don't want to hijack this marvelous video thread, but what is the problem with a wider head?

Miles
 
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