Morphing Airframe rotor disc control

davh12

Newbie
Did the first power up over the week-end. Rotor blades still have too much flex. Excessive coning & lose lift. I will switch over to a CF blade. The chord width was about .50" less than what is required as well about the same length with regard to span. Additional mast bearing needed as well as a thrust bearing. More to follow.

Dave
 

davh12

Newbie
Machined a new rotor hub using industrial nylon. Got the new rotor blades, trimmed down rebalanced, and rebalanced again after attaching to hub. They have a metal leading edge spar. Good blade. I need to machine a new rotor mast. The 1/8" stainless steel mast apparently bent right at the cross pin gear lock area from the torque during the last power up. My fault. Using titanium rod now. Minor set back. More to follow.
Dave



 

davh12

Newbie
Finished the titanium rotor mast. I may need to replace the redcution gear due to an increase in mast diameter, which in turn I may need a motor with a bit more torque. The weight is the same as the smaller stainless, so no increase in overall weight. Waiting on additional bearings.....again, so I started work on the aluminum mockup so it reflects the updated tilt mech.





 

davh12

Newbie
Replaced the off-set axises gimbal joint with a spherical bearing. Also shortened the vertical down tube to lower the upper airframe for attachment to the lower sliding spherical bearing assembly.

 

davh12

Newbie
New mast bearings are in. Working on a different reduction gear. Diameter is .5mm smaller than the first one, it's a bit thinner and lighter, but the pitch guage is the same. Just need center spindle.

Dave
 

davh12

Newbie
Been a while since I worked on my CF prototype. Had foot operation/shock wave treatment to treat bone spur.....too much Infantry stuff and years of humping a ruck sack. I'm having issues with the gear hub.......fabing one...miss having my lathe. So, took a break from it and went back to the mock up again. Shortened the vertal fin and horizontal stab and drilled the tail boom to make it lighter. Working 3 projects at one time so I am way behind. A friend of mine who served in Iraq with me is working with me on an "Anti Torque Recovery System" (ATRS) for tail rotor failure. The particulars are going to be kept in the dark for a while. It's an idea that I came up with a couple of years ago and he was always a "trusty worthy" person I could show my ideas to. He made a suggestion about one part, so I made him a co-inventer. He's at Purdue getting schooled in aerodynamics, but his knowledge and input for this design was prior to his attending Purdue. He's also racking some flight time in fixed wing. More to follow.

 

davh12

Newbie
Working on replacing the singular vertical down tube w/ a dual down tube set up as reflected in the patent. I'm so far behind on the CF prototype as well. Boxing it up and trying to finish it over X mas leave. More to follow.

Dave
 

Friendly

Platinum Member
Its good to see composites being used. I think we will have more of this in the future. nice work and good photos.
 

davh12

Newbie
Freindly,

Thanx and I agree with you about the use of composites. I'm starting to think that I should have used a gas/nitro power plant set up over electric. Trying to keep the weight down and it's such a small airframe. A micro nitro engine has crossed my mind............those little Cox engines about the size of a couple of quarters. We'll see.

Dave
 

davh12

Newbie
Going back to the off set axis gimbal fulcrum which will have about 3 degrees of lateral movement, giving the rotor disc about 5 to 7 degrees of lateral tilt as the hub/disc are a bit higher on the mast above the gimbal fulcrum; finished the dual down tube/struts and rid myself of the single tube; started the tilting mechanism, but only got the lateral tilt plate w/o bearing blocks and the sperical w/o it being attached to the pylon which I have yet to machine out of industrial nylon. The logitudinal lever that attaches to the tilt mechanism spherical pylon is not machined yet. The linear bearing that will allow the lever to have a telescopic motion as the upper airframe tilts forward/aft is not ordered. Wow is it expensive! for one 1/4" ID linear bearing. All changes reflect the design in the patent.






 

davh12

Newbie
Joe,

Yep.spent 3 days last week out in the field. Behind on everything. Went to IL and then to New Jersey to see my wife's family. Tired from traveling, but I got new gears for the "yet to fly" prototype. Hope to have those mounted by the end of this week-end.
Best to you an yours this new year. Enjoy your time with your son.

Dave
 

joe nelson

Senior Member
Thanks Dave, We're counting down the days until his R&R. There's about 20 more days to go until he starts home. I'm not sure how long it will take but we're sure anxious!

I'm glad your project is coming along...mine is in the last 10% that takes 90% of the time,lol.
 

davh12

Newbie
New updates at my web site. Gear mounted on titanium mast......now I need a new electric motor w/ larger spur gear.
 

davh12

Newbie
Joe,

Thanx....still does not fly yet. I need to resolve the reduction gear issue. I know electric motors turn faster than gas engines, but it still does not turn fast enough with the current motor and gear. The diameter and length of the mast increased, so I need more kick. I managed to keep the weight down by using the titanium for the mast. Still a bit of machining to do on it.
 

davh12

Newbie
New electric motor. Thought my wife was going to kill me after she found out the cost was $50 bones. I'm more familiar with auto and house electrical wiring....is the blue wire a ground? I more acustom to green or bare ground wires.

Dave


 

Jazzenjohn

Gold Supporter
Dave, what you have is a brushless motor for a ducted fan. If so, to use it will require a 40 amp brushless motor controller for speed control. The previous motor appeared to me to be a typical permanent magnet motor. The two motors would not use the same motor controller. The pictured motor is for 10-12 volts and can put out over 1/3 hp at nearly 40,000 rpm.

My opinion is that you see if it would be possible to return the motor and work on the model all the way to the point that it would only need the speed control and motor to fly. At that point, then weigh the model and try to determine what blades/motor/controller combo would be best. Alternatively you might find that the large gears you were using before might happen to be near the reduction you need.
 

davh12

Newbie
Jazzenjohn,

Yep...I need the extra kick. It may take additional gear change outs or install a speed controller to keep it down. The mast is titanium, and longer and even though I used carbon fiber, the airframe is heavier than the RC helo that I canibalized for the parts. I also need to increase the batt carriage to fit the larger battery...tweak tweak and still more tweking to do. But I do appreciate your input. If smacks the wall of my apartment. I'll post the video clip..lol
Thanx again

Regards,

Dave
 
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