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Old Feb 03, 2013, 11:02 PM
CSU Chico, Flight Club
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United States, CA, Chico
Joined Sep 2012
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Originally Posted by cwleveck View Post
I read about a third of a way into this discussion then skipped to the end.... so forgive me if this has already been said.
If you used a linkage that had a running sliding fit for its attachment to the aircraft an arm could self adjust to your cg by being attached at the cog.
In other words, let the arm self level. As it picks up weight it moves within its attachment with a bearing, let gravity do the work. Just don't get it swinging and you should be ok.
i need a pic, i m not following you explanation...
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Old Feb 04, 2013, 04:56 AM
Mosquito 6
Joined Jun 2012
483 Posts
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Originally Posted by rimshotcopter View Post
I love these servos and spent many nights dreaming about them. Just never made the investment. Then I came upon the Arduino with the MWC firmware, then there was no need for them.
Glad you found an elegant solution. Yeah, they're kinda pricey, but I'm gonna build a gimbal that doesn't look like something of a contraption from the movie "Wild Wild West" Pani ZS20 only about 205 grams.

Gotta say .. I find the Duct-Shroud part of this thread most interesting. I guess maybe 4 layers of 2.9 oz CF might do it .. and a precision mold/form. I've never worked with it .. gotta be lighter than the cardboard tube I'm guessing..

Cheers ..
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Old Feb 04, 2013, 05:10 AM
Mosquito 6
Joined Jun 2012
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Originally Posted by Test Pilot Mafia View Post
ok very cool vid...

i need capabilites that the quads cant provide...
- a lift arm, to pick stuff up with out over flying the object.
- a full forward view for a special color seeking camera.
- a mostly unobstructed view for my lidar, at least 270'

also bicopters can:
- have fewer peices to break. (Half as many props escs, and motors)
- have fewer but stronger structures

but yes they are more trouble to build and figure out.
You could build an H-43 Huskie .. twin rotor .. lidar on the roof in front of the rotors. The lift arm is gonna be a problem for any aircraft. Need some balancing mechanism like used in tower cranes.

Cheers ..
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Old Feb 04, 2013, 10:22 AM
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United States, OR, Salem
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Thats what i said! I need to upload a napkin drawing.....
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Old Feb 04, 2013, 10:32 AM
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4 layers is a bunch. dont underestimate the strength of the stuff. Also it can be really easy or very difficult to work with depending on what you want it to look like when your done. When I first started doing it you not only used it for strength but also for asthetics (sp?)
So the idea was you would use beautiful fibers in a clear epoxy and your finish depended on two things:
1. the finish quality of the mold to make the outside glossy finish.
2. you had to get all the fibers lined up and somehow add resin without disturbing them.
Imagine gift wrapping a present and you want it to be perfect but all you have is hair and syrup. Now make sure you get even coverage as thin as you can so the hair can be seen through the syrup when your done, and while your at it paint it on in such a way that all the hair is perfectly straight, no wavy lines. and keep it consistent around corners...

Today you can get structural stuff and pre impregnated cloth. I would stay away from the prepreg because its hard to squeeze the epoxy out to make anything light.
Id use one layer of heavier cloth and like i said in yesterdays post find a plastic container to use as a mold.
A final note. It seems to me that the most important factor in getting the duct to work more efficiently is the shape of the blades, which should be VERY different, so I don't think just using our props inside the duct is going to help as much, and also the size of the duct in relation to the turbine blades.
And I quote " By sizing the ductwork appropriately, the designer can adjust the air velocity through the fan to allow it to operate more efficiently at higher air speeds than a propeller would."
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Old Feb 04, 2013, 10:37 AM
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looking for a knapkin but picture a counterbalanced crain and now make the arm slide in a cradle under your center of gravity. The idea is that as you pick up something with the arm it could pull in or out with a counterbalance that would keep you balanced in level flight. By allowing the arm to pull closer the counterweight is extended which should make that end heavier and compensate for the load.
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Old Feb 14, 2013, 03:25 PM
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United States, CA, Los Angeles
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Got around to doing the first park test with the new weight shifting mechanics, much improved over the last park test. She still requires some PID tuning and some YAW refinements but she is progressing nicely. I am a very slow builder and never rush anything because I don't have allot of resources. One crash can set me back months, so I take my time making sure each step are complete.

I am very hopeful the next Park test will be with the props rotated to about 20', not sure if I will attempt this rotation in air or do a running take off. I am almost sure it will be the rolling takeoff because I can shut down quickly if things do not go as planned.

Mollie VTOL - Weight Shifting Park 02 (2 min 35 sec)
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Old Feb 14, 2013, 03:31 PM
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Going to order one 5S battery with the same or close to the same weight as my 4S 5000mah battery for testing.
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Old Feb 14, 2013, 03:47 PM
Will fly for food
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Weight is our enemy, isn't it?
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Old Feb 14, 2013, 03:49 PM
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Just increase power, simple.
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Old Feb 14, 2013, 04:19 PM
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Note: Unlike a Quad with four motors, we have two. So we have room to expand. On my other copters, I have some much larger motors (42mm diameter) and will be installing 15" props.
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Old Feb 14, 2013, 04:22 PM
Will fly for food
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Originally Posted by rimshotcopter View Post
Just increase power, simple.
Haha -

I believe this is what we call a race condition.
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Old Feb 14, 2013, 04:23 PM
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Originally Posted by ilektron View Post
Haha -

I believe this is what we call a race condition.
What are you talking about?
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Old Feb 14, 2013, 04:56 PM
Will fly for food
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Originally Posted by rimshotcopter View Post
What are you talking about?
Oops, a race condition is something different. What I meant was a 'runaway' condition. Such as an arms race. Although this is a power/weight race.

Next thing you know you'll be figuring out how much thrust a nuclear reactor can produce... (I'm looking at you, Avengers)
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Old Feb 14, 2013, 05:02 PM
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Originally Posted by ilektron View Post
Oops, a race condition is something different. What I meant was a 'runaway' condition. Such as an arms race. Although this is a power/weight race.

Next thing you know you'll be figuring out how much thrust a nuclear reactor can produce... (I'm looking at you, Avengers)
Maybe you will but I will not. have no need for one. Ha!
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