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        Discussion Scratch Single-Rotor 23" 6.5 Ounces

#1 sr71fan Feb 27, 2009 06:18 PM

Scratch Single-Rotor 23" 6.5 Ounces
 
11 Attachment(s)
After watching and flying Michael Connally's modified Twirl a couple of weeks ago, the autogyro bug bit me again.

This one has a Bluecor fuselage, Protection Board III tailfeathers, and Depron blades. A 1300KV Blue Wonder motor on 2S 460 and a 9/4.7 prop is twice the power it needs to fly.

Since the wind always blows here, I had to wait 'til almost Midnight to get in a test-flight. A local church parking lot seemed like a good place. I was pleasantly surprised when it lifted off gently and began to climb. Lots of trimming, and a CG adjustment (battery) later, I put on my hat camera for some video. This is flight #3...

Can't wait to try it out in calm daylight air!

Gary

AutoGyro Test-Flight at Night (1 min 47 sec)

#2 Norfolk Flyer Feb 28, 2009 03:05 AM

Nice one Gary!

Stability looks impressive, where did your CG end up?

Please post video of a daylight flight when you can.

John

#3 SafeLandings Feb 28, 2009 03:42 AM

Gary ,
I agree with John 'well done'!..is that a clockwise spinning rotor you have on there?..it looked like it didnt want to turn to the left? I like the simple roll control, hinging the whole mast! I suppose with the weight of blue foam and depron the torque needed for roll is really not an issue.
Looking forward to some more footage ;) ..great video :D


Regards Rich

#4 sr71fan Feb 28, 2009 09:00 PM

John,

The CG is just behind the rotor shaft. 5mm maybe. I'll post if I ever get to fly in good air.

Rich,

Yes, it's clockwise when viewed from above. I expected it to turn right, but it wants to turn left. Maybe because the battery is on the left side. I'll center it, and perhaps move the battery forward, and see what happens.

Thank you both for your comments.

Gary

#5 Norfolk Flyer Mar 01, 2009 03:09 AM

Gary,

I am fairly new to autogyros, having just completed and flown my DAG R1, but one thing I have discovered from this forum, and in practice is that a counter clockwise rotor (as on the DAG) makes the model want to roll right due to rotor coning, so I assume that a clockwise rotor (as on yours) will presumably induce a left roll, is this what you are experiencing?

I have tried to understand this by reading the sticky threads from Mickey, but can't get my head round it yet!

Alternative explanation anyone?

John

#6 JochenK Mar 01, 2009 04:23 AM

Gary,

very nice flying for a submarine. I suggest that you put your c.g. in front of the rotor thrust line instead of behind it. This usuallly gives you a more stable flight and will probably reduce the tendency to turn left.

Jochen

#7 SafeLandings Mar 01, 2009 04:58 AM

Quote:

Originally Posted by Norfolk Flyer
Gary,

I am fairly new to autogyros, having just completed and flown my DAG R1, but one thing I have discovered from this forum, and in practice is that a counter clockwise rotor (as on the DAG) makes the model want to roll right due to rotor coning, so I assume that a clockwise rotor (as on yours) will presumably induce a left roll, is this what you are experiencing?

I have tried to understand this by reading the sticky threads from Mickey, but can't get my head round it yet!

Alternative explanation anyone?

John

John,
I think its just purely down to the direction of rotation, watching the video it seemed to turn easier to the right. Exactly the opposite to our anti clockwise rotating gyros..I cant understand why your DAG wants to turn right easier :confused: all mine are the opposite and are biased to left hand circuits..still as long as they fly thats all that matters ;) ..I suppose they all have there own flying characteristics.

Regards Rich

#8 mnowell129 Mar 01, 2009 07:36 AM

Quote:

Originally Posted by Norfolk Flyer
I have tried to understand this by reading the sticky threads from Mickey, but can't get my head round it yet!

If you start a thread asking this question, I will try to explain. There is an explanation. I don't want to hijack this thread.

#9 sr71fan Mar 02, 2009 12:21 PM

2 Attachment(s)
I moved the rotor tilt hinge line up toward the hub, moved the battery forward, and centered the battery. Maybe this will tame it down a bit. It wanted to turn left really bad. I was flying right circles because it would turn violently left if I let go of the stick. Still haven't had a chance to fly again, but I'm sure it's gonna be a lot better. I guess the left turn was from coning; following Mickey's explanation. Thanks everyone!

Gary

#10 sr71fan Mar 03, 2009 10:32 AM

1 Attachment(s)
Finally had a chance to fly in daylight!. Mods really helped. Got it to trim hands-off at half throttle. This is gonna be lots of fun indoors. Thanks to everyone for the suggestions!

Gary

AutoGyro 2 First Daytime Flight (1 min 25 sec)


AutoGyro2 Short Test Hop (0 min 35 sec)

#11 Norfolk Flyer Mar 04, 2009 10:11 AM

Thanks for the new videos Gary,
You must be really pleased with the way it's turning out.

Glad you're following Mickey's coning explanation. I am certainly learning a lot.

Regards
John (UK)

#12 SafeLandings Mar 04, 2009 10:58 AM

John,
It kind of goes over the top of my head sometimes and I have to read the explanations many times before it sinks into my thick head..LOL. I understand the theory but in practice they just dont react the same (in my experiences)..to what the theory states.
If it flies I tend not to worry too much...I test, trim, fly and forget! there is always away around a particular problem using trims or weight shifting etc.
Gary ..well done on an excellent flying gyro, I look forward to seeing more video footage.

Regards Rich

#13 ampmaker Mar 05, 2009 01:41 PM

To SR71FAN

I really like the simplicity of your design. Would it be possible for you to supply some of the details as follows:

1. Rotor tilt angle relative to fuselage center line.

2. Rotor disk height relative to fuselage center line

3.Amount of motor down thrust

4.Approximate vertical fin area

5. Approximate horizontal stabilizer area.

I would really like to build an autogyro and your design seems like a great starter build. The answers to the 5 questions would be a big benefit.

Thanks,

Ampmaker

#14 sr71fan Mar 05, 2009 11:39 PM

Ampmaker,

1. 15 degrees
2. 5 inches
3. 7 degrees
4. 25 sq in
5. 50 sq in

Have fun!

Gary

#15 ampmaker Mar 06, 2009 10:02 AM

Gary,

Thanks for the info. It looks like I have a new weekend project. I will post pictures to show my progress.

Hugh


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