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Old Jan 20, 2013, 10:05 PM
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Originally Posted by Derek_S View Post
Now just waiting on the bearings and glass fiber to arrive in the mail.. All else seems ready except the rotors, which I have made, just not reinforced with piano wire or anything.

I have a question, though: Why 3 blades on the main rotor? Why is this most common? Just curious why are 4 or 2 seemingly less common in models autogyros?
Derek

Four blades can be very smooth and stable but the increase in lift is not proportional , Two blades can be harder to get up to auto rotation , so the happy medium most often used on a trainers and sport models is three. Also the tri plate is simple to fabricate ,but still requires to be done accurately,hence the pdf on the previous page.

Note the wire l/e or other suitable method is required to bring the blade cog in line with the rotor bolt

Tom.
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Old Jan 22, 2013, 11:29 AM
Lets make it remote control!!!
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very very smooth bird looks great
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Old Jan 22, 2013, 01:02 PM
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Just got my glass fiber in the mail, so now I am just waiting on bearings to maiden.

Does anyone have a better picture of how the bearings and the motor mount work on the rotor hub? I have 2 bearings right now (flanged ones on order) so I decided to try and pre-asssemble it, and was not sure how it works.

Do 2 bearings go inside the motor mount, then one on top? Kind of like this diagram?
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Old Jan 22, 2013, 01:36 PM
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Derek.

Just turn the top bearing over (flange at top).

BTW do not use the grub screws supplied with the blue wonder as they will distort the bearings. Also be sure to use a 3mm nyloc nut under the bottom bearing to prevent compressing the bearings when the rotor bolt is tightened up.Ideally the center bearing would have a thrust washer either side ,but I have not used them in any of mine .

Hope that helps.

Tom.
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Old Jan 22, 2013, 02:01 PM
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Maybe my picture was not clear enough, or I am not understanding still. So, I made a better picture.

This is what I thought it should look like, (of course it may vary if needing extra spacer, washer, or locknut to get clearances) in general.

With the pictures in the manual, it is just hard to see exactly.
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Old Jan 22, 2013, 02:21 PM
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Sorry Derek I have so many autogyros! ......the bearing holder is mounted under the plate and the plate center hole is made to fit the top bearing flange so it ends up flush with the plate top. . Just turn the top bearing over ( flange at the top ) Just to confirm two flange and one standard bearing are used with all my blue wonder bearing holders.

I will edit my previous post to avoid confusion. BTW I like your drawings

Tom.
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Old Jan 22, 2013, 02:41 PM
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Able..

http://www.youtube.com/watch?feature...&v=3Pj3c0Xo83s

This link is to the MK 4 better known as the SFH version .The model in your link above is the MK 1 prototype ,which broke all the rules lol.

The hang was five degrees ( nose to short! ) , blades were not balanced, and bolted on at 50% chord via gf tags.
It flew slow and easy but only at one throttle setting. The SFH latest version is more conventional and has a much wider speed range .

Tom.
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Old Jan 22, 2013, 02:43 PM
Lets make it remote control!!!
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Quote:
Originally Posted by Derek_S View Post
Maybe my picture was not clear enough, or I am not understanding still. So, I made a better picture.

This is what I thought it should look like, (of course it may vary if needing extra spacer, washer, or locknut to get clearances) in general.

With the pictures in the manual, it is just hard to see exactly.
nice looking design dont think youll have any problems with some tweaking here and there
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Old Jan 24, 2013, 02:26 PM
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Able..

That's the first time I have ever heard the Crane Fly described as nice looking I thought I was the only one that saw beauty in simplicity .

Tom
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Old Jan 24, 2013, 06:35 PM
Lets make it remote control!!!
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Quote:
Originally Posted by Tom Wright View Post
Able..

That's the first time I have ever heard the Crane Fly described as nice looking I thought I was the only one that saw beauty in simplicity .

Tom
you kiddin i really like them some of what you said their simplicity
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Old Jan 25, 2013, 08:20 PM
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Derek.

Following on from your questions ,the delta plate centre hole needs to be enlarged to 9.5 mm to accept the top bearing flange . Could this have been the omission that prompted your question ?.

Tom.
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Old Jan 26, 2013, 12:29 AM
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I don't know for sure yet Tom. I think maybe if will be more obvious once I have the bearings in hand to mock up the whole assembly (I hear and I forget. I see and I remember. I do and I understand. - Confucius). But yes, I think I am starting to understand the assembly. It was just hard to surmise from the pictures, I guess.

I have also talked to Flying_Flair via pm. We are gonna work out a graphic based on my previous one that better explains the assembly for the ignorant, like me!
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Old Jan 26, 2013, 08:41 AM
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Derek.

I wish to thank you for spotting , what is realy an omission. I understand that you have given permission for your revised drawing to be used to clarify the way the bearing holder is attached to the plate ,thanks again for that great stuff!

My familiarity with the model ,may have lead to making assumptions that the builder would know what to do, so it's certainly not a matter of your ineptitude.

Thanks for your help
Much appreciated.
Tom.
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Old Jan 26, 2013, 03:58 PM
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Rotor Blade Weight.

Hi Tom, first up, thanks for a nice design.

The weather here (Germany) is pretty much like in your neck of the woods at the moment so I decided last night (after a couple of beers ) to knock up a Cranefly, woke up sober this morning and it still seemed like a good idea so off the LHS I went. Not much money later I had most of the wood which I didn't have including 3 lengths of 40 X 10 mm trailing edge stock (I got 3 to make 6 blades, 3 spare, Murphys insurance, what you have you never need ) and started on them first (looks like the most difficult bit). As I was happily sanding away I was thinking about using my new Proxxon bench drill (showing off now) to mill a groove into the nose to glue the 1.5 mm piano wire in. Got me thinking back to when I used to make my own wooden rotor blades for my MFA 500 and then my Morley MXA (my first 2 Helys). I also used to use piano wire in the nose to get the C of G forward and I always bent the rod to make a staple shape at the root to keep it on place. It was not for security when flying as the glue over this length should be enough but in the event of an ‘event’ (crash), it stopped the wire from turning into a guided missile. Not fool proof but in those days I crashed a lot and I never had the wire ‘eject’ from the blade. I will attach a simple (poor) sketch to show what I mean.
Not saying that it is a great idea or a safety must, the effort probably outweighs the safety factor, but even so someone might like the idea.

Paul Bray.
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Old Jan 26, 2013, 05:29 PM
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Hi Paul.
Thanks for the kind comments and taking the time to post your idea.
I do mention returning the l/e wire in the thread notes over on MF, but you drawing would be a nice addition to the pdf ,if you don't mind me using it ?. It's much better than my efforts lol.

Many modern Autogyro blades have a sharp l/e with no under cut to the bottom surface , I call this an Aquilla section as opposed to a Clarke Y ,so if your inset wire does not significantly increase the section nose radius then it will be the same as my blades, which eliminates variables in the design that could change things and make it difficult to comment on any aspect of performance that was subject to a question.
Having said that very few areas could be described as critical ,if the plate is accurate and the rotors follow the approximate section shown, and are of equal weight , and balanced the model should perform as the video indicates.

Thanks again for posting .

Do let us know how the build progresses.

Tom.
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