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More SG6042 blade testing - 4/13/2002 12:10:26 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		Hi Bill,

I finally got a chance to do a little flying today. I had both the single and dual rotor gyros ready with the SG6042 blades.

I removed the lead shot from the blade tips for the single rotor. I first made two flights with the single rotor using my blades to make sure everything was working OK. I turned the Co-Pilot on and off during flight several times to demonstrate for some spectators on the recovery ability of the Co-Pilot. With the Co-Pilot turned off I rolled the gyro over on it’s back and then turned the Co-Pilot back on and never touched the sticks until after it recovered.

After landing I installed the SG6042 blades. Also want to mention that the windsock was hanging straight down. No wind today so I was using the electric drill to pre-spin the rotor. I pre-spun the rotor with the SG6042 blades and unfortunately it reached the end of the runway and never lifted off. It went into some rough ground and knocked the landing gear off and broke the prop. The rotor blades survived OK. No damage. However, I’m not sure what it didn’t lift off but that was my first attempt using these blades with no wind. The rotor looked like it was spinning up good and it looked like it was starting to lift and a few more feet I think it would have.

I was going to test the dual rotor next but I saw lighting on the horizon so I packed up for the day. I will keep you informed on more testing.

Phil
       Post #: 1

More SG6042 blade testing - 4/14/2002 4:13:56 AM   
billf



Posts: 260
Joined: 2/1/2002
From: Hudson, WI, USA
Status: offline 		Hi Phil...
Thanks for the update and your perserverence! It might be worth trying to shim the 6042 blades to give them a bit more positive incidence. Since you indicated they seemed to be spinning up, perhaps the negative incidence at the roots got them spinning, but there wasn't enough positive at the tips to generate a lot of lift????

I had an idea that someday when the wind IS blowing, it might be instructive to hold the plane aloft, until the blades get into autorotation and see if you can sense the tendency to roll side-to-side. See if there is a difference between your blades and the 6042's.

BTW had a good flight with my Prairie Gyro today which has a 4 bladed rotor, with 6042 blades, but with no twist.

Ah well, the mystery continues!

Regards,
Bill

(in reply to floridagyro)
       Post #: 2

More SG6042 blade testing - 4/14/2002 7:19:17 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		Hi Bill,

Did some flying today with both the single and dual rotor gyros. Not a good day for testing as we had lots of wind and very gusty.

I first made a flight with the single rotor using my blades and turned the Co-Pilot on and off during flight and got everything trimmed out as best that I could with the gusty conditions. I modified the rotor hub, which is just a triangular piece of fiberglass. I removed some of the material on the sides of the triangle hoping that it would allow the blades to flex and possibly increase the coning angle. After landing I installed the SG6042 blades. Because of the wind it just hoped off the ground and immediately started it’s rolling side to side. I made one pass around the field but because of the gusting winds decided to land without any further testing.

I then made a flight with the dual rotor, which I flew at Spring Hill using my blades. Again because of the gusty winds was a handful. I then installed the SG6042 blades. The blades were up to speed before the gyro started a rollout and it just hopped off the ground. I didn’t have any problems flying but the gyro was a lot less stable then with my blades. However, with my blades I had to apply a little right rudder for trim and the SG6042 blades didn’t require any trim, which indicates that I was getting equal lift from both rotors. I will do more testing when the winds are a little more constant.

I mount all of my blades with just one bolt in the center of the blade. Do you think moving the mounting hole toward the leading edge would change anything?

Thanks, Phil

(in reply to floridagyro)
       Post #: 3

More SG6042 blade testing - 4/14/2002 9:01:32 PM   
billf



Posts: 260
Joined: 2/1/2002
From: Hudson, WI, USA
Status: offline 		Hi Phil...
Boy you are persistent! I admire your efforts!
Anyway regarding the question of hole location of the blades, I believe that Steve recommends putting the mounting hole on the point along the chord where the blade would hang vertically. In other words on the line where the chordwise CG is located. This usually falls somewhere around 25-30% of the chord back from the leading edge.

I am still puzzled about the side-to-side rolling! I'm goiing to get going on making a set of non-twisted blades hopefully identical to the three twisted ones except for the twist.

Bill

(in reply to floridagyro)
       Post #: 4

More SG6042 blade testing - 4/15/2002 4:42:35 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		Hi Bill,

I will try moving the mounting hole as Steve does on his blades. I have another Co-Pilot, which I plan on mounting on the Gyrobee and see what happens. Also, I was thinking of trying the Gyrobee blades on my gyro. I still have lots of things to try and it makes flying that much more exciting. Also, with the gusty winds I notice that the Co-Pilot would rock the gyro with my blades but then it would dampen out after a few oscillations. It's going to be interesting to see the results from other gyro flyers after they get a chance to test the Co-Pilot.

Phil

(in reply to floridagyro)
       Post #: 5

More SG6042 blade testing - 4/17/2002 5:18:37 AM   
Steve T.


 

Posts: 88
Joined: 1/7/2002
From: Phoenix
Status: offline 		Is this stuff fun or what?

Thanks, both Phil & Bill for keeping us posted on all your experiments. Lots of folks are reading your threads.


_____________________________

Best of Autorotation,

(in reply to floridagyro)
       Post #: 6

SG6042 Blades - 4/17/2002 8:53:56 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		You are right Steve. This is great fun.

Hi Bill,

Another good day of test flying the SG6042 blades on both single and dual rotor autogyros. Today was windy but steady which made almost perfect flying conditions. No doubt about it! After flying with both single and dual rotor and changing back and forth from my blades to the SG6042, my blades provided a much more stable autogyro. After making some slow low passes it became obvious that on the single rotor gyro the coning angle with the SG6042 blades was two or three times greater than my blades using the same triangle fiberglass hub.

After many flights and observations I think I figured out what is going on. The SG6042 blades seem to provide about the same lift as my blades. However, I think they are providing this lift at a much lower RPM than my blades. That would account for large coning angle due to lower G force on the blades. Also, without the G force, stability would also be lacking. Any other guesses?

Come to think of it, somebody did suggest checking the RPM of the blades. Was that you Steve? Some of us are slooooow learners!

Phil

(in reply to floridagyro)
       Post #: 7

More SG6042 blade testing - 4/17/2002 9:56:14 PM   
billf



Posts: 260
Joined: 2/1/2002
From: Hudson, WI, USA
Status: offline 		Good Morning Phil...
Yesterday here it was 80, today it's 50 and a bit too windy to fly.

Your latest results truly are puzzling (disregard my personal e-mail, I hadn't read you post here.) Here are a list of thoughts, from me and others.

1. Steve says rotor rpm that is too slow leads to less gyroscopic stability...Could be a good explanation of why the SG6042's are "squirrely"

2. Using your calculations about centrifugal forces it appears the the heavier 6042's SHOULD have a lower coning angle for the same weight aircraft, assuming they are at the same rpm as your blades. But as you say they may well be spinning at lower rpm.

3. Now, here is another input. When I Florida, Steve flew my Prairie Gyro which has a 4 blade rotor using no-twist SG6042's. It appeared rock stable and Steve even commented it was a "*****cat..or words to that effect. Since he flew it, I have had a number of successful flights, both hand launched and take-offs with no indication of roll instability.

Now another question: Have you detected any differences with the 6042's on your dual rotored aircraft vs 'standard' blades? I recall you mentioned that in one instance the blades were spinning, but you ran out of runway befrore lift-off.

Non-twisted 6042's now out of the vacuum, finishing steps to begin shortly!

Regards,
Bill

(in reply to floridagyro)
       Post #: 8

More SG6042 blade testing - 4/17/2002 10:00:35 PM   
billf



Posts: 260
Joined: 2/1/2002
From: Hudson, WI, USA
Status: offline 		Hi Phil...

I just re-read my recent post. I used the word for *****cat that began with a "p". Apparently the moral censors wouldn't allow publicaton of that word!! Wow are we "pure".

Bill

(in reply to floridagyro)
       Post #: 9

More SG6042 blade testing - 4/18/2002 12:12:25 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		Hi Bill,

Yes, I did hold the blades by hand just to check for spin-up but didn't think to look at the coning angle. One thing that I didn't mention. After flying around for awhile with the 6042 blades the coning angle got so bad that I couldn't sustain flight and had to land. Apparently after awhile the fiberglass gets flexed so much it allowed too much coning. On about the last past in front of me I notice the blades were singing way up. However, after landing I put my blades on the same piece of fiberglass hub and made several flights without any problem.

I have made several flights with the dual rotor gyro. I can fly it OK but it just lacks stability. While making a turn with the 6042 it just wants to roll over. I'm convinced that it's due to slow rotor RPM.

I'm going out to do more testing now.

Phil

(in reply to floridagyro)
       Post #: 10

More SG6042 blade testing - 4/18/2002 12:14:55 AM   
floridagyro



Posts: 511
Joined: 2/24/2002
From: Wimauma, FL, USA
Status: offline 		I think the jury is in! I don't have any wind but I did some half run/walk while holding the blades by hand and checking the blade RPM with a tack. The highest with the SG6042 was about 460 RPM. I then tried my blades the same way and they immediately went to 800 to 900 RPM. I then tried the blades from the Gyrobee, (Steve Tillson design) and they went over 800 RPM. The higher RPM blades kind of whistle and the SG6042 is a whoooooshing sound. Do you think the shape or the width contributes to a slower RPM?

If nothing else, I'm getting in better physical condition.

Phil

(in reply to floridagyro)
       Post #: 11

More SG6042 blade testing - 4/18/2002 8:41:37 PM   
soarrich



Posts: 2470
Joined: 2/1/2002
From: Middletown, NJ, USA
Status: offline 		Phil
If you shim the 6042's to a lower angle of attack wouldn't that increase the RPM?

It was my understanding that the blades will go as fast as they have to make the lift to fly.

I just started my blades today, so far so good.

_____________________________

Rich Border

(in reply to floridagyro)
       Post #: 12

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