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Old Feb 08, 2013, 10:31 PM
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Malaysia, Selangor, Kajang
Joined Jun 2009
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Next we build the metal bits.

This is my first attempt at a pig tail bearing. I didn't have enough wire to do the method in the video so I did it freehand. It's not as easy as it looks. My first attempt was a failure. My second attempt was a bit better.

One difference between how I do it and the video is that I build the front of the bearing inwards. This means that when I trim the excess wire the sharp bit is on the side that is not facing the prop. This means I don't need to grind it flat. Spring steel is not easy to grind.

One word of warning when working with guitar string. The diameter of a guitar string is almost a needle point. It's very sharp. I hurt myself several times wiping the table clean with my bare hands. So if possible keep track of every piece you cut or trim off. I have a wad of tissue that I trim the wire into so that pieces don't go flying everywhere.
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Old Feb 08, 2013, 10:58 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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Ahhh, can't wait for the next instalment. Part 4 can't come soon enough.
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Old Feb 09, 2013, 12:29 AM
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Malaysia, Selangor, Kajang
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Quote:
Originally Posted by Jimmy JFlyer View Post
Ahhh, can't wait for the next instalment. Part 4 can't come soon enough.
Good news. Part4 is here!

Actually I just took a break from typing and had lunch. Writing this up is more work than the actual building. Completed almost everything last night. The only thing left is building the prop. But I need the prop to get the CG.

Now we build all the attachment points for the flying surfaces.
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Old Feb 09, 2013, 07:23 AM
yes, its a flying lamb :)
draganbt's Avatar
Bitola, Republic of Macedonia
Joined Apr 2009
532 Posts
A very enjoyable detailed build thread!

Thank you
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Old Feb 09, 2013, 04:22 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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Quote:
Originally Posted by slebetman View Post
Good news. Part4 is here!.
Sweet! Can't wait for part 5! Very curious to see how you move wing around to get the desired cg.
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Old Feb 09, 2013, 07:14 PM
more balsa please!
dcloin's Avatar
Princeton, In
Joined Jul 2007
788 Posts
I'm really enjoying following your build. I know it takes a lot of time to complete, thanks for making the effort and sharing.
Darvin
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Old Feb 10, 2013, 03:43 PM
TheyreComingToTakeMeAway!
derk's Avatar
USA, ID, Coeur D'Alene
Joined Dec 2003
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i found a similar plane on a german forum: http://www.rc-network.de/forum/showt...=1#post1758667
his plane is a 190mm span and the box is 165 x 85 x 30 mm
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Old Feb 12, 2013, 12:52 PM
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Malaysia, Selangor, Kajang
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Sorry for taking a long time to post this. Writing this up is a lot more work than I thought it would be. The original build was only a single afternoon but this build has taken almost a week to complete. I got kind of tired of writing (in fact, for the past 20 minutes I've been avoiding writing this by watching youtube )

OK, on to building the prop and finding the CG. But first I'd like to mention that the plan isn't final yet. I changed the airfoil from the original to a (hopefully) more efficient one but doing that changed the trim of the plane completely. So the CG location isn't final until I've fully trimmed the plane. Currently the CG is at 5.5cm (roughly 92% MAC).

I also need to update the angles of the wing joiners and length of the wing posts.

Also, I forgot to mention previously that I used 1.5mm balsa (approx. 1/16") for the wing posts instead of 1mm.

Now on to the build. The original had plastic cup props. Check out my flying wing thread for a description of building the plastic prop: http://www.rcgroups.com/forums/showt...3#post23757838

This time around I'm building a tracing paper prop. Partly because it's an alternative to people who can't source good (crappy/cheap) thin plastic cups. Partly because it's 100mg lighter than the plastic prop. Oh, another thing: the prop template in the plan is too narrow. A wider prop should be better at absorbing the torque from the rubber.
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Old Feb 12, 2013, 12:54 PM
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Malaysia, Selangor, Kajang
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For glide tests I simply attach the wings onto the motor stick using small bits of masking tape. Unfortunately I forgot to take a picture of it before gluing the post onto the stick.
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Old Feb 12, 2013, 04:56 PM
For us He died, in me He lives
Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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Very very cool. Thx so much for taking the time to do all this work. I say again, I can not wait to try this guy.
Wonderful job on the build log.
Jimmy
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Old Feb 12, 2013, 08:56 PM
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Jimmy JFlyer's Avatar
United States, MI, Saint Clair Shores
Joined Dec 2008
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So I am looking closely at your prop build. What material would you suggest if I can not find trace paper? I am assuming that trace paper is a bit stiff, and will hold the curve on it's own?
I too would like to use something other than plastic in the interest of saving weight.
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Old Feb 12, 2013, 11:22 PM
TheyreComingToTakeMeAway!
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USA, ID, Coeur D'Alene
Joined Dec 2003
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if you guys want a way of making thin wood for props or other items, i came up with a nifty way of doing it here: http://www.hippocketaeronautics.com/...c,13783.0.html
its worked well so far, and saves time from having to sand down sheet wood, which i find very frustrating at times.
i will try and get some of the pictures up into that thread soon also.
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Old Feb 13, 2013, 01:27 AM
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Malaysia, Selangor, Kajang
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Balsa shavings is the ultimate of course. I don't know if you know him Derk but Shadow from hippocketaeronautics gave me one of his balsa shavings and it's thin enough to be almost transparent. He used a razor plane to make the shavings.

Approximate weights of 5 inch props from different materials:

Thin plastic cup: 0.3g
Tracing paper: 0.2g
70gsm A4 paper: 0.16g
Very thin balsa shavings: 0.08g
Balsa sanded down to approx 1/64": 0.2g

So, you can use regular A4 paper, which would be lighter but would be a bit more fragile and less stiff. You can also shave balsa down to almost paper thin 1/64 or less. A prop without camber works quite well actually. There is in fact an AMA class called the A6 where the rules state that the prop must be made from 1/32 balsa with flat plate airfoil. And my friend's A6 outperforms my plane.
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Old Feb 17, 2013, 09:15 PM
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Just a bump to say that I'm still working on this. Just been a bit busy with other projects and real-world work lately. I'm rebuilding the motor stick because I found that I don't really like the pig tail bearing. I'm going back to my original L shaped bearing.

I'm also in the process of taking measurements and updating the plans. I'll probably finish that tomorrow.

Sorry for the really slow progress. I'll make up for it this week.
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Old Feb 18, 2013, 07:50 AM
For us He died, in me He lives
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United States, MI, Saint Clair Shores
Joined Dec 2008
5,103 Posts
Excited to see the bump!
Thx for the update. I'm dieing to see how this next guy turns out.
So if I may ask, when you get a free moment, (i know this is hard to come buy these days, believe me I do) how would you describe why you prefer your bearing vs the pigtail?

I saw some of Shadow's work and comments in the Hip Pocket forum. I joined the other night and have been reading through all sorts of stuff.
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