Morphing Airframe rotor disc control

davh12

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Back from the filed and clean again. Finishing the tilt mechanism on the mock up this week-end, video tomorrow, and the tail rotor on the CF prototype.

Dave
 

davh12

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Still waiting for parts.................postal service.

Dave
 

All_In

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Still waiting for parts.................postal service.

Dave
Dave don't worry, it will be here in.... (wait for it) .... 'TWO WEEKS'?:wacko:
 

davh12

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All In,

Thanx...............I'll get through it, but the week-ends are the only days that I can get things done. last few weeks of the cycle for these new Lieutenants. Little breathing room then. At least for a few weeks.

Regards,

Dave
 

Resasi

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Dave very interesting to see and follow your build thread as you work your way through the problems you encounter.

A flying machine's a flying machine no matter what the scale.
 

davh12

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Resasi,
Thanks. I just wished that I had more time. I enjoy the mechanical problem solving. Keeps my head clear to focus on just that and all of the others issues that botherd me throughout the day dissolve. Take care.
Dave
 

davh12

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Fabricated a new rotor hub to fit the blades; no issues with balance. Shortened the titanium rotor mast and mounted the hub to the mast with one of the first rubber grommets (upper) that will allow the hub to teeter flex. The blade bending should negate most of the dissymmetry of lift. Tail rotor mounted and wiring for the motor is "rough in" and not yet soldered. New mast bearing will be 11/64". Now I must re solder a new receiver antenna as some one came into my apartment while I was in the field, went through my stuff, pulled the antenna out of the receiver and went through some of my miliatry records. Seems like I can never win. The Apartment maintenance people were in the apartments changing filters. Should have the bearings mounted next week-end or the week-end after, I think I can solder the antenna this week-end. More to follow.

Dave





 

RotorTom

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Dave,

I have been following your thread from he beginning. No doubt you have skills when it comes to designing and crafting ... but I have a basic question that no one has asked: Why?

You call it a morphing airframe for rotor control but I can see no advantage over conventional rotor controls.

The airframe morphs on the ground when compared to stable ground, but when in the air there is no stable base and therefore it seems the morphing is just around a CG? Isn't that what conventional controls do anyway?

Can you give a basic explanation (for "dummies") as to what you are trying to accomplish and why is has advantages over conventional flight controls?

Thanks very much!

Tom
 

davh12

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Rotor Tom,

Maintenance costs...........and an attempt to make it easier to fly with fewer parts. No one seems to ever question "is there a better way?" Perhaps there is not, but I'm crossing the "line in the dirt". If it works, all the better. If not, no issues from my point of view. I'm just willing to try. Look up on Youtube the "GEN H4" helicopter. The concept works, but the GEN H4 is fixed pitch with no "auto" capabilities. The whole gimbaled airframe is the only morphing part. The CG (in theory) flexes rather than a lateral shift as seen in Charles Seibel's helo. Most of my design is an attempt to improve and humbly "do it better than the GEN H4, Airscooter, and Seibels craft. Push the limits. My wife says I have OCD, but mechanical in nature. Rotorcraft are my favorite, but anything that questions the "usuall method" intrigues me.

You're right about the CG with most helos, but even from my limited experience, it appears as if conventional helo CGs are manipulated with the respective controls, but from one point atop the rotor mast within a static airframe. The ideal area for CG manipulation is lower down the rotor mast for better stability...like a pendulum...in theory..lol. The only way to do that is allow the airframe to change mechanically in flight and tie the weight of the pilot in with it as well. It's not as easy to see in small scale. Larger scale (full collective) there would be some what of a swashplate, but for collective pitch control only. I'm still in the crawl phase. I could be complety wrong, but what if I'm right? At any rate, I'm enjoying the process and I have no committments to anyone. Just my efforts. Thanks for asking. I do enjoy the feedback. We'll see what happens. First tethered flight is in a couple of weeks.

Look at the Baldwin aircraft Mono Tilt Rotor:

www.baldwintechnology.com/

Baldwin takes advantage of weight distribution at a distance farther from the hub and incorporates mechanical morphing.

The R22 uses a longer mast for better control and stability for a larger rotor disc area.

Dave
 

joe nelson

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BRAVO Dave!!!!
 

All_In

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Nice work Dave!!!

It's looking good Joe!
 

davh12

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Rock Island IL
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Few UAS on the "govy" side
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none, except as LZ passenger and vertical "rope" descents
Thanx....................hope everyone else is wrapped up in their respective projects. Just enjoying things working a little faster now. Getting hot here in Georgia.

Dave
 

davh12

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Messages
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Location
Rock Island IL
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Few UAS on the "govy" side
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none, except as LZ passenger and vertical "rope" descents
Lower mast bearing mounted, mast attached, main drive motor mounted. Picture below, airframe is inverted allowing the glue to dry for the lower bearing housing. Still on track for tethered flight tomorrow.

Dave
 

davh12

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Joined
Jun 11, 2010
Messages
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Location
Rock Island IL
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Few UAS on the "govy" side
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none, except as LZ passenger and vertical "rope" descents
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Ok.............tether flight did not go as well as I had hoped. I had a problem with torsional flex in the vertical struts of the lower airframe causing the airframe as a whole to vibrate, but the biggest problem was that the motor, battery and receiver are up a little too high. When the helicopter gets light on it's frame just before it lifts off the surface, it wants to tip over. So, I at least know what to fix and adjust now. On a better note: the forward and aft tilt work well. I can hold the helicopter with 2 fingers and it will hover on it's "own", but some changes need to be made. In an effort to cut weight, I left out the lateral support struts on the vertical struts. They would have eliminated some of the torsional flex, but we learn from trial and error. Titanium has a bit more "spring flex to it and that also coulc have caused an issue. The video below is after the tether flight. During the tether flight I realized my "skevies" were showing so I left that clip out.....lol. The helicopter would lift up a bit and roll laterally. I have some work to do, but I'm not discouraged. As you can see in this video clip, the mast tilt seems to be ok.

Dave


YouTube - Tether (Ipod Video).mov
 
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