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My gyrocopter.

Old 10-30-2014, 03:21 PM
  #1  
soarrich
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Default My gyrocopter.

This is my current project, it's taking about ten times as long as I anticipated, but the end is in sight. It's a electric gyro-copter. I have a 42mm motor, with a 70 amp ESC, 5 cell 5000 mah battery, Orange 2.4 Rx and 7955TG digital with 333oz./.15 sec servos. The main structure is 3/4" aluminum "C" channel filled with pine down the length, but I used oak on the crosspiece due to the way I mounted the landing gear. The seat is also a battery compartment, it's made from a anti-freeze jug. I'll add a fixed stab and a moveable rudder. I have to build the rotor tilt mechanism and the delta rotor head. It's getting heavy so I was concerned if it would move in the grass, so I tested it in the backyard. I don't think that's a problem, this thing will out accelerate any plane I've got!
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Old 10-30-2014, 03:38 PM
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COOL!
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Old 10-31-2014, 03:06 AM
  #3  
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Looking forward to seeing it progress!
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Old 10-31-2014, 04:06 AM
  #4  
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A very interesting build...

Here's a web-site that may provide a few tips that could increase your progress:

http://www.micro-flight.com/MIA%20Autogyros.htm
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Old 10-31-2014, 04:55 AM
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Originally Posted by soarrich View Post
This is my current project, it's taking about ten times as long as I anticipated, but the end is in sight. It's a electric gyro-copter. I have a 42mm motor, with a 70 amp ESC, 5 cell 5000 mah battery, Orange 2.4 Rx and 7955TG digital with 333oz./.15 sec servos. The main structure is 3/4" aluminum "C" channel filled with pine down the length, but I used oak on the crosspiece due to the way I mounted the landing gear. The seat is also a battery compartment, it's made from a anti-freeze jug. I'll add a fixed stab and a moveable rudder. I have to build the rotor tilt mechanism and the delta rotor head. It's getting heavy so I was concerned if it would move in the grass, so I tested it in the backyard. I don't think that's a problem, this thing will out accelerate any plane I've got!
I see a very big problem with your model. No shoulder Harness
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Old 11-18-2014, 11:33 PM
  #6  
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Default Stab, vertical fin and rudder.

Slow progress, I had to put a new door on the garage/workshop.

I built a stab out of 1/4"x3/8" balsa sticks. I pinned the last "rib" on each side with a toothpick, they are the most likely to get hit and damaged. The stab is going to be fixed, because I'm making this a DC gyro, but I had to strengthen it so that I can mount some flying wires to help support the vertical fin. The fin and rudder may seem small, but they are going to be in the prop-blast, so I think the will be big enough. I'm "Old School" after I made the parts I went over all the wood joints with Ambroid glue, the parts seem pretty strong. I've incorporated some mounting points into the rudder for a pull pull system.

The front of the stab will be pinned to the landing gear bar, the centerline will be screwed to the trailing bar.
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Old 11-19-2014, 04:29 AM
  #7  
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Originally Posted by soarrich View Post
Slow progress, I had to put a new door on the garage/workshop.

I built a stab out of 1/4"x3/8" balsa sticks. I pinned the last "rib" on each side with a toothpick, they are the most likely to get hit and damaged. The stab is going to be fixed, because I'm making this a DC gyro, but I had to strengthen it so that I can mount some flying wires to help support the vertical fin. The fin and rudder may seem small, but they are going to be in the prop-blast, so I think the will be big enough. I'm "Old School" after I made the parts I went over all the wood joints with Ambroid glue, the parts seem pretty strong. I've incorporated some mounting points into the rudder for a pull pull system.

The front of the stab will be pinned to the landing gear bar, the centerline will be screwed to the trailing bar.

Looking good BTW, I get to do the Maiden flight on the Gyrocopter, Also, I never Flew a Gyrocopter Before LOL

Last edited by CHELLIE; 11-19-2014 at 12:23 PM.
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Old 12-02-2014, 05:38 AM
  #8  
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I uploaded a video of the gyro in the backyard. I completed then mounted the vertical fin/rudder and stab. While testing it the prop sucked the rudder cables into the blades and cut them. Slow going, good thing I built a HK Skipper, 10 minute build, so I know it's the gyro not me.
http://youtu.be/voPxssbOLgg
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Old 12-10-2014, 05:06 AM
  #9  
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Default rotor-head

This is the rotor-head that I've made. I use plywood with PP5 plastic as a hinge made from a plastic shoebox lid.
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Old 12-10-2014, 05:20 AM
  #10  
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Default Rotor

This is my rotor plate. I'm going to use two blades, the angle cut feathers the blade as it goes up. I use the thickness of the ply to keep the blades from going down, the gap on the top allows the blade to go up. The advancing blade makes more lift than the retreating blade, both blades are held out the same by centifical force and gravity, so the advancing blade is feathered making less lift and speeding the blades up.

After I took the picture I realized I had assembled it wrong, the angle needs to go the other way to work.
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Old 12-17-2014, 04:53 AM
  #11  
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Default New rotor hub.

I decided to get a rotor and blades from http://www.flyingbalsa.com/
So now it has three blades rather than two. I made the blades 26.5" which works out to about 2200 sq in of rotor disk.

The rotor-head built easily. I changed the bearing to fit a 1/4" rotoshaftr, I then made the aluminum stand-off you can just see under the rotor head, it tapers to just touch the inner bearing race.

I added a power switch because I'm chicken.
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Old 12-17-2014, 09:33 AM
  #12  
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These Gyros are neet, I have a Question, why does the rotor blades have about a - 3 degree incidence to them, it look like there is a wood shim to give the rotor blade a neg incidence, I have read where some rotor blade are set at a 3 to 5 degree neg incidence and some are set at a positive incidence, I would think that the rotor copter would not want to get off the ground with a Neg Incidence to the blades, maybe the blades bend and change angle under a load, I dont know, thats why I am Asking, Take care and have fun, Chellie

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Old 12-17-2014, 10:57 AM
  #13  
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The lift is from the airfoil effects. A "wing" (rotor is just a rotary wing) for a glider will typically be at slight negative incidence in level flight. Part of the lift is then pulling forward and part is holding the aircraft in the air.

A gyrocopter's rotor sort of works on the same principal. Part of the lift is pulling the blades forward.

Gyrocopters prove that the Bernouli explanation for lift does explain PART of the lift of an asymmetrical airfoil.

If it was a fully symetrical airfoil the negative incidence would drive the gyrocopter down instead of up.
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Old 12-17-2014, 03:39 PM
  #14  
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SG6042 airfoil zero lift angle is -5, so setting them at -2 still makes lift. Like fhhuber wrote part of the lift lifts the gyro, the other part spins the blades, without the negative pitch angle there would be no reason for the blades to spin forwards, they would in fact spin backwards because of the drag created. It's hard to tell which way the blades are spinning in a video, but by looking at the blades you can tell which way they will spin. When you see flat rotor-blades they will always turn backwards, airfoiled blades are designed to turn forwards. The reason they are spinning and the gyro is flying is they are making lift in a deferent way. The flat plate blades are stalled and are flying like a kite, lots of drag and some lift. The airfoiled blades are not stalled and are flying like an airplane's wing, some of the lift is used to lift the gyro, some to overcome drag and pull the blade forward. When the blade goes forward it makes more lift, making it go forward even faster making even more lift, on and on. On a airfoiled gyrocopter you can actually hear when it gets in this mode, it sounds like helicopter, like the blades are powered. This works the same as Iceboats that can sail 120mph in a 40mph wind, even a regular sailboat you see this as the apparent wind is pulled forward as you gain speed.
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Old 12-18-2014, 12:14 AM
  #15  
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Default First attempt at flight.

http://youtu.be/SNr7BslX65o



I think I have too much pitch control, and might need a little nose weight.

Last edited by Don Sims; 12-18-2014 at 01:04 AM.
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Old 12-18-2014, 01:03 AM
  #16  
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I've always been fascinated by these birds but never got one. I'm going to watch this thread. Great job so far. Looks like it's all going to come down to a little tweaking to get it to be a nice flyer.

Joe
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Old 12-18-2014, 06:18 AM
  #17  
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I've watched this over and over, this is what I've come up with:

The model needs just a little more nose weight.
The rotor needs a little more lean back.
The pitch control needs less movement.


When I was going away on the grass at 32 seconds I think it should have lifted off by itself, it had the rotor speed. When I pulled back on the stick, the gyro jumped off the ground, that tells me I need more lean back on the rotor. My reflex was to give it a little nose down, but it dove, so I think I have too much throw in pitch and not forward enough CG.
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Old 12-18-2014, 07:48 AM
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Originally Posted by fhhuber View Post
The lift is from the airfoil effects. A "wing" (rotor is just a rotary wing) for a glider will typically be at slight negative incidence in level flight. Part of the lift is then pulling forward and part is holding the aircraft in the air.

A gyrocopter's rotor sort of works on the same principal. Part of the lift is pulling the blades forward.

Gyrocopters prove that the Bernouli explanation for lift does explain PART of the lift of an asymmetrical airfoil.

If it was a fully symetrical airfoil the negative incidence would drive the gyrocopter down instead of up.
Originally Posted by soarrich View Post
SG6042 airfoil zero lift angle is -5, so setting them at -2 still makes lift. Like fhhuber wrote part of the lift lifts the gyro, the other part spins the blades, without the negative pitch angle there would be no reason for the blades to spin forwards, they would in fact spin backwards because of the drag created. It's hard to tell which way the blades are spinning in a video, but by looking at the blades you can tell which way they will spin. When you see flat rotor-blades they will always turn backwards, airfoiled blades are designed to turn forwards. The reason they are spinning and the gyro is flying is they are making lift in a deferent way. The flat plate blades are stalled and are flying like a kite, lots of drag and some lift. The airfoiled blades are not stalled and are flying like an airplane's wing, some of the lift is used to lift the gyro, some to overcome drag and pull the blade forward. When the blade goes forward it makes more lift, making it go forward even faster making even more lift, on and on. On a airfoiled gyrocopter you can actually hear when it gets in this mode, it sounds like helicopter, like the blades are powered. This works the same as Iceboats that can sail 120mph in a 40mph wind, even a regular sailboat you see this as the apparent wind is pulled forward as you gain speed.
Thank you for the Explanation The Neg Pitch had me wondering Take care, Chellie
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Old 12-18-2014, 07:49 AM
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Originally Posted by soarrich View Post
I've watched this over and over, this is what I've come up with:

The model needs just a little more nose weight.
The rotor needs a little more lean back.
The pitch control needs less movement.


When I was going away on the grass at 32 seconds I think it should have lifted off by itself, it had the rotor speed. When I pulled back on the stick, the gyro jumped off the ground, that tells me I need more lean back on the rotor. My reflex was to give it a little nose down, but it dove, so I think I have too much throw in pitch and not forward enough CG.
Good Try Just need to get it Tweaked in Now, Take care, Chellie
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Old 12-19-2014, 12:35 AM
  #20  
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The link I previously posted here discusses that issue and provides some tips.......
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Old 12-19-2014, 05:30 AM
  #21  
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Originally Posted by pizzano View Post
The link I previously posted here discusses that issue and provides some tips.......
Yea, I had looked at that, I just went back and looked at it again. Knowing what I know now other than the fixes I said I'm going to do the only thing I would do differently is I would not have backed off the throttle, I would have let it climb however much it could for 3 or 4 seconds.
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Old 12-21-2014, 03:06 AM
  #22  
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Default Second attempt at flight.

http://youtu.be/X8hF8CP-fK8

I'm looking for suggestions.
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Old 12-21-2014, 03:21 AM
  #23  
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Bummer. Hope you get it sorted soon. Could C.G. maybe be hyper critical on this type of bird? I have an Andy Lennon book around here somewhere and I thought there was something in there on gyro-copters. I'll see if I can find that book.

Joe
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Old 12-22-2014, 02:36 PM
  #24  
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Joe
I think I found the problem. I bought a new rotor-head and blades from FlyingBalsa and built them, but the instructions where for the normal blades they put on the rotor-head, not the larger blades I used. I found that the blades are at about -5 which is the zero lift angle of the airfoil. I'm going to change the angle of the blades and try again.
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Old 12-23-2014, 01:06 AM
  #25  
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Originally Posted by soarrich View Post
Joe
I think I found the problem. I bought a new rotor-head and blades from FlyingBalsa and built them, but the instructions where for the normal blades they put on the rotor-head, not the larger blades I used. I found that the blades are at about -5 which is the zero lift angle of the airfoil. I'm going to change the angle of the blades and try again.
Hi I found this Info on RCG on rotor copter CG / Hang Angle,Hope That helps, Take care and have fun, Chellie


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Hi...presuming the gyro is of the tractor type? we don not use the termanolgy of CoG..this is for fixed wing and could become very confusing. If the gyro is held from the top of its rotor mast the nose should hang down..we call this 'the hang angle'. If you measure the hang angle from the horizontal.. most gyros have between 10 and 18 degrees of hang. The more hang angle you have the more rearward tilt you will need on your rotor disc for a level flight path, the less you have the more unstable in pitch it will become. No 2 gyros are the same and each gyro has to be trimmed to suit...its always better to start with more hang angle and go from there.


Regards Rich
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